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Improve todo accounting script.
[misc] / todo.py
diff --git a/todo.py b/todo.py
index 8c911fb1a9247325fcd603a2e65ed6b9269f41d0..3ea09b0d7b7e42b4893c15b7274b7de85c7343bf 100644 (file)
--- a/todo.py
+++ b/todo.py
@@ -5,388 +5,795 @@ from datetime import datetime, timedelta
 from urllib.parse import parse_qs
 from jinja2 import Environment as JinjaEnv, FileSystemLoader as JinjaFSLoader 
 from urllib.parse import urlparse
+from os.path import split as path_split
 db_path = '/home/plom/org/todo_new.json'
 server_port = 8082
 DATE_FORMAT = '%Y-%m-%d'
 j2env = JinjaEnv(loader=JinjaFSLoader('todo_templates'))
 
-class Task:
 
-    def __init__(self, db, title_history=None, tags_history=None, default_effort_history=None, links_history=None):
-        self.db = db
-        self.title_history = title_history if title_history else {}
-        self.tags_history = tags_history if tags_history else {}
-        self.default_effort_history = default_effort_history if default_effort_history else {}
-        self.links_history = links_history if links_history else {}
-        self.visible = True
 
-    def _set_with_history(self, history, value):
-        keys = sorted(history.keys())
-        if len(history) == 0 or value != history[keys[-1]]:
-            history[str(datetime.now())[:19]] = value
+def today_date(with_time=False):
+    length = 19 if with_time else 10
+    return str(datetime.now())[:length]
 
-    def _last_of_history(self, history, default):
-        keys = sorted(history.keys())
-        return default if 0 == len(history) else history[keys[-1]]
 
-    @classmethod
-    def from_dict(cls, db, d):
-        return cls(
-               db,
-               d['title_history'],
-               {k: set(v) for k, v in d['tags_history'].items()},
-               d['default_effort_history'],
-               {k: set(v) for k, v in d['links_history'].items()})
 
-    def to_dict(self):
-        return {
-            'title_history': self.title_history,
-            'default_effort_history': self.default_effort_history,
-            'tags_history': {k: list(v) for k,v in self.tags_history.items()},
-            'links_history': {k: list(v) for k,v in self.links_history.items()},
-        }
+class AttributeWithHistory:
 
-    @property
-    def default_effort(self):
-        return self._last_of_history(self.default_effort_history, 1)
+    def __init__(self, default_if_empty, history=None, then_date='2000-01-01', set_check=None, alt_get=None):
+        self.default = default_if_empty
+        self.then_date = then_date
+        self.history = history if history else {}
+        self.set_check = set_check
+        self.alt_get = alt_get 
 
-    @default_effort.setter
-    def default_effort(self, default_effort):
-        self._set_with_history(self.default_effort_history, default_effort)
+    def set(self, value):
+        if self.set_check:
+            self.set_check(value)
+        keys = sorted(self.history.keys())
+        if len(self.history) == 0 or value != self.history[keys[-1]]:
+            self.history[today_date(with_time=True)] = value
 
-    def default_effort_at(self, queried_date):
-        ret = self.default_effort_history[sorted(self.default_effort_history.keys())[0]]
-        for date_key, default_effort in self.default_effort_history.items():
+    def at(self, queried_date):
+        if self.alt_get:
+            ret = self.alt_get('at', queried_date)
+            if ret is not None:
+                return ret
+        if 0 == len(self.history):
+            return self.default
+        ret = self.history[sorted(self.history.keys())[0]]
+        for date_key, item in self.history.items():
             if date_key > f'{queried_date} 23:59:59':
                 break
-            ret = default_effort
+            ret = item
         return ret
 
     @property
-    def current_default_effort(self):
-        return self.default_effort_at(self.db.selected_date)
+    def now(self):
+        if self.alt_get:
+            ret = self.alt_get('now')
+            if ret is not None:
+                return ret
+        keys = sorted(self.history.keys())
+        return self.default if 0 == len(self.history) else self.history[keys[-1]]
 
     @property
-    def title(self):
-        return self._last_of_history(self.title_history, '')
+    def then(self):
+        if self.alt_get:
+            ret = self.alt_get('then')
+            if ret is not None:
+                return ret
+        return self.at(self.then_date)
 
-    @title.setter
-    def title(self, title):
-        self._set_with_history(self.title_history, title)
 
-    def title_at(self, queried_date):
-        ret = self.title_history[sorted(self.title_history.keys())[0]]
-        for date_key, title in self.title_history.items():
-            if date_key > f'{queried_date} 23:59:59':
-                break
-            ret = title
-        return ret
 
-    @property
-    def current_title(self):
-        return self.title_at(self.db.selected_date)
+class Task:
 
-    @property
-    def tags(self):
-        return self._last_of_history(self.tags_history, set())
+    def __init__(self,
+            db,
+            id_,
+            title_history=None,
+            tags_history=None,
+            default_effort_history=None,
+            subtask_ids_history=None,
+            comment=''):
+        self.db = db
+        self.id_ = id_
+        self.title = AttributeWithHistory('', title_history, self.db.selected_date)
+        self.tags = AttributeWithHistory(set(), tags_history, self.db.selected_date)
+        self.default_effort = AttributeWithHistory(0.0, default_effort_history, self.db.selected_date, alt_get=self.subtasks_sum_maker())
+        self.subtask_ids = AttributeWithHistory(set(), subtask_ids_history, self.db.selected_date, set_check=self.subtask_loop_checker())
+        self.comment = comment
 
-    @tags.setter
-    def tags(self, tags):
-        self._set_with_history(self.tags_history, set(tags))
+        self.visible = True
 
-    @property
-    def links(self):
-        return self._last_of_history(self.links_history, set())
+    @classmethod
+    def from_dict(cls, db, d, id_):
+        t = cls(
+               db,
+               id_,
+               d['title_history'],
+               {k: set(v) for k, v in d['tags_history'].items()},
+               d['default_effort_history'],
+               {k: set(v) for k, v in d['subtasks_history'].items()},
+               d['comment'])
+        return t
 
-    @links.setter
-    def links(self, links):
-        self._set_with_history(self.links_history, set(links))
+    def to_dict(self):
+        return {
+            'title_history': self.title.history,
+            'default_effort_history': self.default_effort.history,
+            'tags_history': {k: list(v) for k, v in self.tags.history.items()},
+            'subtasks_history': {k: list(v) for k, v in self.subtask_ids.history.items()},
+            'comment': self.comment,
+        }
 
     @property
-    def id_(self):
-        for k, v in self.db.tasks.items():
-            if v == self:
-                return k
+    def subtasks(self):
+        subtasks = []
+        for id_ in self.subtask_ids.now:
+            subtasks += [self.db.tasks[id_]]
+        return subtasks
+
+    def subtask_loop_checker(self):
+        def f(subtask_ids_now):
+            loop_msg = "can't set subtask, would create loop"
+            for id_ in subtask_ids_now:
+                if id_ == self.id_:
+                    raise PlomException(loop_msg)
+                elif id_ in self.db.tasks.keys():
+                    subtask = self.db.tasks[id_]
+                    f(subtask.subtask_ids.now)
+        return f 
+
+    def subtasks_sum_maker(self):
+        def f(f_name, queried_date=None):
+            subtask_ids_to_check = getattr(self.subtask_ids, f_name)
+            if queried_date:
+                subtasks = [self.db.tasks[id_] for id_ in subtask_ids_to_check(queried_date)]
+            else:
+                subtasks = [self.db.tasks[id_] for id_ in subtask_ids_to_check]
+            if len(self.subtasks) > 0:
+                summe = 0
+                for subtask in self.subtasks:
+                    if queried_date:
+                        to_add = getattr(subtask.default_effort, f_name)
+                        summe += to_add(queried_date)
+                    else:
+                        summe += getattr(subtask.default_effort, f_name)
+                return summe
+            return None
+        return f
+
+    def matches(self, search):
+        if search is None:
+            return False
+        else:
+            return search in self.title.now or search in self.comment or search in '$'.join(self.tags.now)
 
 
 class Day:
 
-    def __init__(self, db, todos=None, comment=''):
+    def __init__(self, db, date, comment=''):
+        self.date = date 
         self.db = db
-        self.todos = todos if todos else {}
         self.comment = comment
         self.archived = True
+        self.linked_todos_as_list = []
+        self.todos = {}
 
     @classmethod
-    def from_dict(cls, db, d):
-        todos = {}
+    def from_dict(cls, db, d, date=None):
         comment = d['comment'] if 'comment' in d.keys() else ''
-        day = cls(db, todos, comment)
-        for uuid, todo_dict in d['todos'].items():
-            day.add_todo(uuid, todo_dict)
+        day = cls(db, date, comment)
+        for id_ in d['linked_todos']:
+            day.linked_todos_as_list += [db.todos[id_]]
         return day
 
     def to_dict(self):
-        d = {'comment': self.comment, 'todos': {}}
-        for task_uuid, todo in self.todos.items():
-            d['todos'][task_uuid] = todo.to_dict()
+        d = {'comment': self.comment, 'linked_todos': []}
+        for todo_id in self.linked_todos.keys():
+            d['linked_todos'] += [todo_id]
         return d
 
-    def add_todo(self, id_, dict_source=None):
-        self.todos[id_] = Todo.from_dict(self, dict_source) if dict_source else Todo(self)
-        return self.todos[id_]
+    @property
+    def linked_todos(self):
+        linked_todos = {}
+        for todo in self.linked_todos_as_list:
+            linked_todos[todo.id_] = todo
+        return linked_todos
 
     def _todos_sum(self, include_undone=False):
         s = 0
-        for todo in [todo for todo in self.todos.values() if todo.done]:
-            s += todo.effort
-        if include_undone:
-            for todo in [todo for todo in self.todos.values() if not todo.done]:
-                s += todo.day_effort if todo.day_effort else 0
+        for todo in [todo for todo in self.linked_todos.values()
+                     if self.date in todo.efforts.keys()]:
+            day_effort = todo.efforts[self.date]
+            if todo.done:
+                s += day_effort if day_effort else todo.task.default_effort.at(self.date)
+            elif include_undone:
+                s += day_effort if day_effort else 0 
         return s
 
     @property
     def todos_sum(self):
         return self._todos_sum()
 
-    @property
-    def todos_sum2(self):
-        return self._todos_sum(True)
-
-    @property
-    def date(self):
-        for k, v in self.db.days.items():
-            if v == self:
-                return k
-
 
 class Todo:
 
-    def __init__(self, day, done=False, day_effort=None, comment='', day_tags=None, importance=1.0):
-        self.day = day
-        self.done = done
-        self.day_effort = day_effort
+    def __init__(self,
+                 db,
+                 id_,
+                 task,
+                 done=False,
+                 comment='',
+                 day_tags=None,
+                 importance=1.0,
+                 efforts=None,
+                 child_ids=None):
+        self.id_ = id_
+        self.db = db 
+        self.task = task 
+        self._done = done
+        self._efforts = efforts if efforts else {}
         self.comment = comment
         self.day_tags = day_tags if day_tags else set()
         self.importance = importance
+        self.child_ids = child_ids if child_ids else [] 
+
+        self.parents = [] 
 
     @classmethod
-    def from_dict(cls, day, d):
-        return cls(day, d['done'], d['day_effort'], d['comment'], set(d['day_tags']), d['importance'])
+    def from_dict(cls, db, d, id_):
+        todo = cls(
+                db,
+                id_,
+                db.tasks[d['task']],
+                d['done'],
+                d['comment'],
+                set(d['day_tags']),
+                d['importance'],
+                d['efforts'],
+                d['children'])
+        return todo
 
     def to_dict(self):
-        return {'done': self.done, 'day_effort': self.day_effort, 'comment': self.comment, 'day_tags': list(self.day_tags), 'importance': self.importance}
+        return {
+                'task': self.task.id_,
+                'done': self.done,
+                'comment': self.comment,
+                'day_tags': list(self.day_tags),
+                'importance': self.importance,
+                'efforts': self.efforts,
+                'children': self.child_ids}
+
+    @property
+    def parent(self):
+        return self.parents[0] if len(self.parents) > 0 else None 
+
+    @property
+    def title(self):
+        return self.task.title.at(self.earliest_date)
+
+    @property
+    def children(self):
+        return [self.db.todos[id_] for id_ in self.child_ids]
+
+    @children.setter
+    def children(self, children):
+        self.child_ids = [child.id_ for child in children]
 
     @property
     def default_effort(self):
-        return self.task.default_effort_at(self.day.date)
+        return self.task.default_effort.at(self.earliest_date)
 
     @property
-    def effort(self):
-        if self.day_effort:
-            return self.day_effort
+    def done(self):
+        if len(self.children) > 0:
+            for child in self.children:
+                if not child.done:
+                    return False
+            return True
         else:
-            return self.day_effort if self.day_effort else self.default_effort
+            return self._done
+
+    @done.setter
+    def done(self, doneness):
+        self._done = doneness
 
     @property
-    def task(self):
-        for k, v in self.day.todos.items():
-            if v == self:
-                return self.day.db.tasks[k]
+    def efforts(self):
+        if self.children:
+            efforts = {} 
+            for date in self._efforts.keys():
+                efforts[date] = None
+            for child in self.children:
+                to_add = None 
+                for date, effort in child.efforts.items():
+                    if not date in efforts.keys():
+                        efforts[date] = None 
+                    if effort is not None:
+                        to_add = effort
+                    elif child.done:
+                        to_add = child.task.default_effort.at(date)
+                if to_add is not None:
+                    if efforts[date] is not None:
+                        efforts[date] += to_add
+                    else:
+                        efforts[date] = to_add
+            return efforts
+        else:
+            return self._efforts
+
+    @efforts.setter
+    def efforts(self, efforts_dict):
+        self._efforts = efforts_dict
 
     @property
-    def title(self):
-        return self.task.title_at(self.day.date)
+    def all_days_effort(self):
+        total = 0
+        for effort in self.efforts.values():
+            total += effort if effort else 0
+        if self.done:
+            total = max(total, self.task.default_effort.at(self.latest_date))
+        return total
+
+    def matches(self, search):
+        if search is None:
+            return False
+        else:
+            return search in self.comment or search in '$'.join(self.tags) or search in self.title
+
+    def is_effort_removable(self, date):
+        if not date in self.efforts.keys():
+            return False
+        if self.efforts[date]:
+            return False
+        if self.done and date == self.latest_date:
+            return False
+        return True
+
+    @property
+    def path(self):
+        path = ''
+        if self.parent:
+            path = f'{self.parent.path}{self.parent.title}:'
+        return path
 
     @property
     def tags(self):
-        return self.day_tags | self.task.tags
+        return self.day_tags | self.task.tags.now
+
+    @property
+    def day_effort(self):
+        return self.efforts[self.db.selected_date]
+
+    @property
+    def day(self):
+        return self.db.days[self.earliest_date]
+
+    @property
+    def sorted_effort_dates(self):
+        dates = list(self.efforts.keys())
+        dates.sort()
+        return dates
 
-    def internals_empty(self):
-        return len(self.comment) == 0 and len(self.day_tags) == 0
+    @property
+    def earliest_date(self):
+        return self.sorted_effort_dates[0]
+
+    @property
+    def latest_date(self):
+        return self.sorted_effort_dates[-1]
 
 
 class TodoDB(PlomDB):
 
-    def __init__(self, prefix, selected_date=None, t_filter_and = None, t_filter_not = None, hide_unchosen=False, hide_done=False):
+    def __init__(self,
+            prefix,
+            selected_date=None,
+            t_filter_and = None,
+            t_filter_not = None,
+            hide_unchosen=False,
+            hide_done=False):
         self.prefix = prefix
-        self.selected_date = selected_date if selected_date else str(datetime.now())[:10]
+        self.selected_date = selected_date if selected_date else today_date()
         self.t_filter_and = t_filter_and if t_filter_and else []
         self.t_filter_not = t_filter_not if t_filter_not else []
         self.hide_unchosen = hide_unchosen
         self.hide_done = hide_done
+
         self.days = {}
         self.tasks = {}
         self.t_tags = set()
+        self.todos = {}
         super().__init__(db_path)
 
+    # savefile I/O
+
     def read_db_file(self, f):
         d = json.load(f)
-        for date, day_dict in d['days'].items():
-            self.days[date] = self.add_day(dict_source=day_dict)
-        for day in self.days.values():
-            for todo in day.todos.values():
-                for tag in todo.day_tags:
-                    self.t_tags.add(tag)
-        for uuid, t_dict in d['tasks'].items():
-            t = self.add_task(id_=uuid, dict_source=t_dict)
-            for tag in t.tags:
+        for id_, t_dict in d['tasks'].items():
+            t = self.add_task(id_=id_, dict_source=t_dict)
+            for tag in t.tags.now:
+                self.t_tags.add(tag)
+        for id_, todo_dict in d['todos'].items():
+            todo = self.add_todo(todo_dict, id_)
+            self.todos[id_] = todo 
+            for tag in todo.day_tags:
                 self.t_tags.add(tag)
+        for date, day_dict in d['days'].items():
+            self.add_day(dict_source=day_dict, date=date)
+        for todo in self.todos.values():
+            for child in todo.children:
+                child.parents += [todo]
+            for date in todo.efforts.keys():
+                if not date in self.days.keys():
+                    self.add_day(date)
+                if not todo in self.days[date].linked_todos_as_list:
+                    self.days[date].linked_todos_as_list += [todo]
         self.set_visibilities()
 
-    def set_visibilities(self):
-        for uuid, t in self.tasks.items():
-            t.visible = len([tag for tag in self.t_filter_and if not tag in t.tags]) == 0\
-                    and len([tag for tag in self.t_filter_not if tag in t.tags]) == 0\
-                    and ((not self.hide_unchosen) or uuid in self.selected_day.todos.keys())
-        for day in self.days.values():
-            for todo in day.todos.values():
-                todo.visible = len([tag for tag in self.t_filter_and if not tag in todo.day_tags | todo.task.tags ]) == 0\
-                    and len([tag for tag in self.t_filter_not if tag in todo.day_tags | todo.task.tags ]) == 0\
-                    and ((not self.hide_done) or (not todo.done))
-
     def to_dict(self):
-        d = {'tasks': {}, 'days': {}}
+        d = {'tasks': {}, 'days': {}, 'todos': {}}
         for uuid, t in self.tasks.items():
              d['tasks'][uuid] = t.to_dict()
         for date, day in self.days.items():
             d['days'][date] = day.to_dict()
+            for todo in day.todos.values():
+                d['todos'][todo.id_] = todo.to_dict()
+        for id_, todo in self.todos.items():
+            d['todos'][id_] = todo.to_dict()
         return d
 
-    @property
-    def selected_day(self):
-        if not self.selected_date in self.days.keys():
-            self.days[self.selected_date] = self.add_day()
-        return self.days[self.selected_date]
-
     def write(self):
         dates_to_purge = []
         for date, day in self.days.items():
-            if len(day.todos) == 0 and len(day.comment) == 0:
+            if len(day.linked_todos) == 0 and len(day.comment) == 0:
                 dates_to_purge += [date]
         for date in dates_to_purge:
             del self.days[date]
         self.write_text_to_db(json.dumps(self.to_dict()))
 
-    def add_task(self, id_=None, dict_source=None, return_id=False):
-        t = Task.from_dict(self, dict_source) if dict_source else Task(self)
+    # properties 
+
+    @property
+    def selected_day(self):
+        if not self.selected_date in self.days.keys():
+            self.days[self.selected_date] = self.add_day(date=self.selected_date)
+        return self.days[self.selected_date]
+
+    # table manipulations 
+
+    def add_day(self, date, dict_source=None):
+        day = Day.from_dict(self, dict_source, date) if dict_source else Day(self, date)
+        self.days[date] = day 
+        return day
+
+    def add_task(self, id_=None, dict_source=None):
         id_ = id_ if id_ else str(uuid4())
+        t = Task.from_dict(self, dict_source, id_) if dict_source else Task(self, id_)
         self.tasks[id_] = t
-        if return_id:
-            return id_, t
-        else:
-            return t
+        return t
 
-    def add_day(self, dict_source=None):
-        return Day.from_dict(self, dict_source) if dict_source else Day(self)
+    def update_task(self, id_, title, default_effort, tags, subtask_ids, comment):
+        task = self.tasks[id_] if id_ in self.tasks.keys() else self.add_task(id_)
+        task.title.set(title)
+        task.default_effort.set(default_effort)
+        task.tags.set(tags)
+        task.subtask_ids.set(subtask_ids)
+        task.comment = comment 
 
-    def show_day(self, task_sort=None):
-        task_sort = task_sort if task_sort else 'title' 
-        current_date = datetime.strptime(self.selected_date, DATE_FORMAT)
-        prev_date = current_date - timedelta(days=1)
-        prev_date_str = prev_date.strftime(DATE_FORMAT)
-        next_date = current_date + timedelta(days=1)
-        next_date_str = next_date.strftime(DATE_FORMAT)
-        task_rows = []
-        for uuid, task in self.tasks.items():
-            if not task.visible:
-                continue
-            todo = None
-            if uuid in self.selected_day.todos.keys():
-                todo = self.selected_day.todos[uuid]
-                if not todo.visible:
-                    continue
-            task_rows += [{'uuid': uuid, 'task': task, 'todo': todo}] 
-        if task_sort == 'title':
-            task_rows.sort(key=lambda r: r['task'].title)
-        elif task_sort == 'default_effort':
-            task_rows.sort(key=lambda r: r['task'].default_effort, reverse=True)
-        elif task_sort == 'done':
-            task_rows.sort(key=lambda r: 0 if not r['todo'] else r['todo'].day_effort if r['todo'].day_effort else r['task'].default_effort if r['todo'].done else 0, reverse=True)
-        elif task_sort == 'importance':
-            task_rows.sort(key=lambda r: 0.0 if not r['todo'] else r['todo'].importance, reverse=True)
-        elif task_sort == 'chosen':
-            task_rows.sort(key=lambda r: False if not r['todo'] else True, reverse=True)
-        elif task_sort == 'comment':
-            task_rows.sort(key=lambda r: '' if not r['todo'] else r['todo'].comment, reverse=True)
-        return j2env.get_template('day.html').render(db=self, action=self.prefix+'/day', prev_date=prev_date_str, next_date=next_date_str, task_rows=task_rows, sort=task_sort)
+    def add_todo(self, todo_dict=None, id_=None, task=None, efforts=None):
+        id_ = id_ if id_ else str(uuid4())
+        if todo_dict:
+            todo = Todo.from_dict(self, todo_dict, id_)
+        elif task and efforts:
+            todo = Todo(self, id_, task, efforts=efforts)
+            children = []
+            for child_task in task.subtasks:
+                children += [self.add_todo(task=child_task, efforts=efforts)]
+            todo.child_ids = [child.id_ for child in children]
+        self.todos[id_] = todo 
+        return todo
+
+    def _update_todo_shared(self, id_, done, comment, importance):
+        todo = self.todos[id_]
+        todo.done = done
+        todo.comment = comment 
+        todo.importance = importance 
+        return todo
+
+    def update_todo_for_day(self, id_, date, effort, done, comment, importance):
+        todo = self._update_todo_shared(id_, done, comment, importance)
+        todo.efforts[date] = effort 
+
+    def update_todo(self, id_, efforts, done, comment, tags, importance, children):
+        todo = self._update_todo_shared(id_, done, comment, importance)
+        if len(efforts) == 0 and not todo.children:
+            raise PlomException('todo must have at least one effort!')
+        todo.children = children
+        todo.efforts = efforts 
+        for date in todo.efforts:
+            if not date in self.days.keys():
+                self.add_day(date=date) 
+            if not self in self.days[date].linked_todos_as_list:
+                self.days[date].linked_todos_as_list += [todo]
+        todo.day_tags = tags
+
+    def delete_todo(self, id_):
+        todo = self.todos[id_]
+        dates_to_delete = []
+        for date in todo.efforts.keys():
+            dates_to_delete += [date]
+        for date in dates_to_delete:
+            self.delete_effort(todo, date, force=True)
+        for parent in todo.parents:
+            parent.child_ids.remove(todo.id_)
+        del self.todos[id_]
+
+    def delete_effort(self, todo, date, force=False):
+        if (not force) and len(todo.efforts) == 1:
+            raise PlomException('todo must retain at least one effort!')
+        self.days[date].linked_todos_as_list.remove(todo)
+        del todo.efforts[date]
+
+    # views
 
     def show_calendar(self, start_date_str, end_date_str):
         self.t_filter_and = ['calendar']
         self.t_filter_not = ['deleted']
         self.set_visibilities()
+        start_date_obj, end_date_obj = self.get_limit_days_from_date_strings(start_date_str, end_date_str)
         days_to_show = {}
-        todays_date = str(datetime.now())[:10]
-        target_start_str = start_date_str if start_date_str else sorted(self.days.keys())[0]
-        target_start = todays_date if target_start_str == 'today' else target_start_str
-        target_end_str = end_date_str if end_date_str else sorted(self.days.keys())[-1]
-        target_end = todays_date if target_end_str == 'today' else target_end_str
-        start_date = datetime.strptime(target_start, DATE_FORMAT)
-        end_date = datetime.strptime(target_end, DATE_FORMAT)
-        for n in range(int((end_date - start_date).days) + 1):
-            current_date_obj = start_date + timedelta(n)
-            current_date = current_date_obj.strftime(DATE_FORMAT)
-            if current_date not in self.days.keys():
-                days_to_show[current_date] = self.add_day()
+        for n in range(int((end_date_obj - start_date_obj).days) + 1):
+            date_obj = start_date_obj + timedelta(n)
+            date_str = date_obj.strftime(DATE_FORMAT)
+            if date_str not in self.days.keys():
+                days_to_show[date_str] = self.add_day(date_str)
             else:
-                days_to_show[current_date] = self.days[current_date]
-            days_to_show[current_date].weekday = datetime.strptime(current_date, DATE_FORMAT).strftime('%A')[:2]
-        return j2env.get_template('calendar.html').render(db=self, days=days_to_show, action=self.prefix+'/calendar', today=str(datetime.now())[:10], start_date=start_date_str, end_date=end_date_str)
-
-    def show_todo(self, task_uuid, selected_date, referer):
-        if selected_date not in self.days.keys():
-           self.days[selected_date] = self.add_day() 
-        if task_uuid in self.days[selected_date].todos:
-            todo = self.days[selected_date].todos[task_uuid]
-        else:
-            todo = self.days[selected_date].add_todo(task_uuid)
-        return j2env.get_template('todo.html').render(db=self, todo=todo, action=self.prefix+'/todo', referer=referer)
-
-    def update_todo_mini(self, task_uuid, date, day_effort, done, importance):
-        if date not in self.days.keys():
-           self.days[date] = self.add_day() 
-        if task_uuid in self.days[date].todos.keys():
-            todo = self.days[date].todos[task_uuid]
+                days_to_show[date_str] = self.days[date_str]
+            days_to_show[date_str].month_title = date_obj.strftime('%B') if date_obj.day == 1 else None 
+            days_to_show[date_str].weekday = datetime.strptime(date_str, DATE_FORMAT).strftime('%A')[:2]
+
+        return j2env.get_template('calendar.html').render(
+                selected_date=self.selected_date,
+                days=days_to_show,
+                start_date=start_date_str,
+                end_date=end_date_str)
+
+    def show_do_todos(self, sort_order=None):
+        prev_date_str, next_date_str = self.neighbor_dates()
+        todos = [t for t in self.selected_day.linked_todos_as_list
+                 if t.visible
+                 and not t.children]
+        if sort_order == 'title':
+            todos.sort(key=lambda t: t.task.title.then)
+        elif sort_order == 'done':
+            todos.sort(key=lambda t: t.day_effort if t.day_effort else t.default_effort if t.done else 0, reverse=True)
+        elif sort_order == 'default_effort':
+            todos.sort(key=lambda t: t.default_effort, reverse=True)
+        elif sort_order == 'importance':
+            todos.sort(key=lambda t: t.importance, reverse=True)
+        return j2env.get_template('do_todos.html').render(
+                day=self.selected_day,
+                tags=self.t_tags,
+                filter_and=self.t_filter_and,
+                filter_not=self.t_filter_not,
+                prev_date=prev_date_str,
+                next_date=next_date_str,
+                todos=todos,
+                sort=sort_order,
+                hide_done=self.hide_done)
+
+    def show_todo(self, id_, return_to, search, start_date, end_date):
+        todo = self.todos[id_]
+        start_day, end_day = self.get_limit_days_from_date_strings(start_date, end_date)
+        if start_day < datetime.now() - timedelta(days=2):
+            end_day = start_day + timedelta(days=3)
+            end_date = end_day.strftime(DATE_FORMAT)
+        legal_dates = []
+        for n in range(int((end_day - start_day).days) + 1):
+            day = start_day + timedelta(n)
+            legal_dates += [day.strftime(DATE_FORMAT)]
+        filtered_todos = [t for t in self.todos.values()
+                          if t.visible
+                          and t != todo
+                          and (len(search) == 0 or t.matches(search))] 
+        date_filtered_todos = [] 
+        for date in legal_dates:
+            for filtered_todo in filtered_todos:
+                if filtered_todo in date_filtered_todos:
+                    continue
+                if date in filtered_todo.efforts.keys():
+                    date_filtered_todos += [filtered_todo]
+        return j2env.get_template('todo.html').render(
+                filter_and=self.t_filter_and,
+                filter_not=self.t_filter_not,
+                tags=self.t_tags,
+                todo=todo,
+                filtered_todos=date_filtered_todos,
+                child_todos=todo.children,
+                return_to=return_to,
+                start_date=start_date,
+                end_date=end_date)
+
+    def show_task(self, id_, return_to='', search=''):
+        task = self.tasks[id_] if id_ else self.add_task()
+        selected = task.id_ in self.selected_day.todos.keys()
+        filtered_tasks = [t for t in self.tasks.values()
+                          if t.visible
+                          and t != task
+                          and (t not in task.subtasks)
+                          and (len(search) == 0 or t.matches(search))] 
+        return j2env.get_template('task.html').render(
+                search=search,
+                tags=self.t_tags, 
+                filter_and=self.t_filter_and,
+                filter_not=self.t_filter_not,
+                filtered_tasks=filtered_tasks,
+                task=task,
+                return_to=return_to)
+
+    def show_tasks(self, expand_uuid):
+        expanded_tasks = {}
+        if expand_uuid:
+            for uuid in self.tasks[expand_uuid].subtask_ids.now:
+                expanded_tasks[uuid] = self.tasks[uuid]
+        return j2env.get_template('tasks.html').render(
+                db=self,
+                filter_and=self.t_filter_and,
+                filter_not=self.t_filter_not,
+                expand_uuid=expand_uuid,
+                expanded_tasks=expanded_tasks)
+
+    def show_pick_tasks(self, search, hide_chosen_tasks, sort_order=None):
+        prev_date_str, next_date_str = self.neighbor_dates()
+
+        chosen_todos = self.selected_day.linked_todos_as_list
+
+        relevant_todos = []
+        for todo in self.todos.values():
+            if todo.done\
+                    or (not todo.visible)\
+                    or (not todo.matches(search))\
+                    or todo.earliest_date >= self.selected_date:
+                continue
+            relevant_todos += [todo] 
+
+        tasks = []
+        chosen_tasks = [todo.task for todo in self.selected_day.linked_todos_as_list]
+        for uuid, task in self.tasks.items():
+            if (not task.visible)\
+                    or (not task.matches(search))\
+                    or (hide_chosen_tasks and task in chosen_tasks):
+                continue
+            tasks += [task]
+
+        if sort_order == 'title':
+            chosen_todos.sort(key=lambda t: t.title)
+            relevant_todos.sort(key=lambda t: t.title)
+            tasks.sort(key=lambda t: t.title.then)
+        elif sort_order == 'effort':
+            chosen_todos.sort(key=lambda t:
+                              t.day_effort if t.day_effort else (t.default_effort if t.done else 0),
+                              reverse=True)
+            relevant_todos.sort(key=lambda t: t.all_days_effort, reverse=True)
+            tasks.sort(key=lambda t: t.default_effort.then, reverse=True)
+
+        return j2env.get_template('pick_tasks.html').render(
+                sort=sort_order,
+                tags=self.t_tags,
+                chosen_todos=chosen_todos,
+                filter_and=self.t_filter_and,
+                filter_not=self.t_filter_not,
+                day=self.selected_day,
+                prev_date=prev_date_str,
+                next_date=next_date_str,
+                tasks=tasks,
+                hide_chosen_tasks=hide_chosen_tasks,
+                relevant_todos=relevant_todos,
+                search=search)
+
+    # helpers
+
+    def set_visibilities(self):
+        for uuid, t in self.tasks.items():
+            t.visible = len([tag for tag in self.t_filter_and if not tag in t.tags.now]) == 0\
+                    and len([tag for tag in self.t_filter_not if tag in t.tags.now]) == 0\
+                    and ((not self.hide_unchosen) or uuid in self.selected_day.todos.keys())
+        for todo in self.todos.values():
+            todo.visible = len([tag for tag in self.t_filter_and if not tag in todo.day_tags | todo.task.tags.now ]) == 0\
+                and len([tag for tag in self.t_filter_not if tag in todo.day_tags | todo.task.tags.now ]) == 0\
+                and ((not self.hide_done) or (not todo.done))
+
+    def get_limit_days_from_date_strings(self, start_date_str, end_date_str):
+        todays_date_obj = datetime.strptime(today_date(), DATE_FORMAT) 
+        yesterdays_date_obj = todays_date_obj - timedelta(1)
+        def get_day_limit_obj(index, day_limit_string):
+            date_obj = datetime.strptime(sorted(self.days.keys())[index], DATE_FORMAT)
+            if day_limit_string and len(day_limit_string) > 0:
+                if day_limit_string in {'today', 'yesterday'}:
+                    date_obj = todays_date_obj if day_limit_string == 'today' else yesterdays_date_obj
+                else:
+                    date_obj = datetime.strptime(day_limit_string, DATE_FORMAT)
+            return date_obj
+        start_date_obj = get_day_limit_obj(0, start_date_str)
+        end_date_obj = get_day_limit_obj(-1, end_date_str)
+        return start_date_obj, end_date_obj
+
+    def neighbor_dates(self):
+        current_date = datetime.strptime(self.selected_date, DATE_FORMAT)
+        prev_date = current_date - timedelta(days=1)
+        prev_date_str = prev_date.strftime(DATE_FORMAT)
+        next_date = current_date + timedelta(days=1)
+        next_date_str = next_date.strftime(DATE_FORMAT)
+        return prev_date_str, next_date_str
+
+
+
+class ParamsParser:
+
+    def __init__(self, parsed_url_query, cookie_db):
+        self.params = parse_qs(parsed_url_query)
+        self.cookie_db = cookie_db
+
+    def get(self, key, default=None):
+        boolean = bool == type(default) 
+        param = self.params.get(key, [default])[0]
+        if boolean:
+            param = param != '0' 
+        return param 
+
+    def get_cookied(self, key, default=None):
+        param = self.get(key, default)
+        if param == '-':
+            param = None
+            if key in self.cookie_db.keys():
+                del self.cookie_db[key]
+        if param is None and key in self.cookie_db.keys():
+            param = self.cookie_db[key]
+        if param is not None:
+            self.cookie_db[key] = param
+        return param
+
+    def get_cookied_chain(self, key, default=None):
+        params = self.params.get(key, default)
+        if params == ['-']:
+            params = None 
+            if key in self.cookie_db.keys():
+                del self.cookie_db[key]
+        if params is None and key in self.cookie_db.keys():
+            params = self.cookie_db[key]
+        if params is not None:
+            self.cookie_db[key] = params
+        return params
+
+
+class PostvarsParser:
+
+    def __init__(self, postvars):
+        self.postvars = postvars
+
+    def has(self, key):
+        return key in self.postvars.keys()
+
+    def get(self, key, on_empty=None):
+        return self.get_at_index(key, 0, on_empty)
+
+    def get_at_index(self, key, i, on_empty=None):
+        if self.has(key) and len(self.postvars[key][i]) > 0:
+            return self.postvars[key][i] 
+        return on_empty 
+
+    def get_float_if_possible(self, key):
+        s = self.get(key)
+        if s is not None:
+            return float(s)
         else:
-            todo = self.days[date].add_todo(task_uuid)
-        todo.day_effort = day_effort
-        todo.done = done
-        todo.importance = importance
-        return todo
+            return None
+
+    def get_all(self, key, on_empty=None):
+        if self.has(key) and len(self.postvars[key]) > 0:
+            return self.postvars[key] 
+        return on_empty
 
-    def collect_tags(self, tags_joined, tags_checked):
+    def get_defined_tags(self, joined_key, key_prefix):
         tags = set()
+        tags_checked = []
+        for k in self.postvars.keys():
+            if k.startswith(key_prefix):
+                tags_checked += [k[len(key_prefix):]]
+        tags_joined = self.get(joined_key, '')
         for tag in [tag.strip() for tag in tags_joined.split(';') if tag.strip() != '']:
             tags.add(tag)
         for tag in tags_checked:
             tags.add(tag)
         return tags
 
-    def update_todo(self, task_uuid, date, day_effort, done, comment, day_tags_joined, day_tags_checked, importance):
-        day_effort = float(day_effort) if len(day_effort) > 0 else None
-        importance = float(importance)
-        todo = self.update_todo_mini(task_uuid, date, day_effort, done, importance)
-        todo.comment = comment
-        todo.day_tags = self.collect_tags(day_tags_joined, day_tags_checked) 
-
-    def show_task(self, id_, referer=''):
-        task = self.tasks[id_] if id_ else self.add_task()
-        return j2env.get_template('task.html').render(db=self, task=task, action=self.prefix+'/task', referer=referer)
-
-    def update_task(self, id_, title, default_effort, tags_joined, tags_checked, links):
-        task = self.tasks[id_] if id_ in self.tasks.keys() else self.add_task(id_)
-        task.title = title
-        task.default_effort = float(default_effort) if len(default_effort) > 0 else None
-        task.tags = self.collect_tags(tags_joined, tags_checked) 
-        task.links = links 
-        for link in links:
-            borrowed_links = self.tasks[link].links 
-            borrowed_links.add(id_)
-            self.tasks[link].links = borrowed_links 
-
-    def show_tasks(self):
-        return j2env.get_template('tasks.html').render(db=self, action=self.prefix+'/tasks')
-
+    def set(self, key, value):
+        self.postvars[key] = [value]
 
 
 class TodoHandler(PlomHandler):
@@ -405,158 +812,202 @@ class TodoHandler(PlomHandler):
         return 'todo', {'cookie_name': 'todo_cookie', 'prefix': default_path, 'cookie_path': default_path}
 
     def do_POST(self):
-        self.try_do(self.config_init)
         self.try_do(self.write_db)
 
     def write_db(self):
         from urllib.parse import urlencode
-        app_config = self.apps['todo'] if hasattr(self, 'apps') else self.config()
-        length = int(self.headers['content-length'])
-        postvars = parse_qs(self.rfile.read(length).decode(), keep_blank_values=1)
+        config = self.apps['todo'] if hasattr(self, 'apps') else self.config_init()
         parsed_url = urlparse(self.path)
-        db = TodoDB(prefix=app_config['prefix'])
-        params_to_encode = []
+        site = path_split(parsed_url.path)[1]
+        length = int(self.headers['content-length'])
+        postvars = PostvarsParser(parse_qs(self.rfile.read(length).decode(), keep_blank_values=1))
+
+        db = TodoDB(prefix=config['prefix'])
+        redir_params = []
+        # if we do encounter a filter post, we repost it (and if empty, the emptying command '-')
         for param_name, filter_db_name in {('t_and', 't_filter_and'), ('t_not', 't_filter_not')}:
             filter_db = getattr(db, filter_db_name)
-            if param_name in postvars.keys():
-                for target in postvars[param_name]:
+            if postvars.has(param_name): 
+                for target in postvars.get_all(param_name, []):
                     if len(target) > 0 and not target in filter_db:
                         filter_db += [target]
                 if len(filter_db) == 0:
-                    params_to_encode += [(param_name, '-')]
-            params_to_encode += [(param_name, f) for f in filter_db]
-
-        def collect_checked(prefix, postvars):
-            tags_checked = []
-            for k in postvars.keys():
-                if k.startswith(prefix):
-                    tags_checked += [k[len(prefix):]]
-            return tags_checked
+                    redir_params += [(param_name, '-')]
+            redir_params += [(param_name, f) for f in filter_db]
+        if site in {'calendar', 'todo'}:
+            redir_params += [('end', postvars.get('end', '-'))]
+            redir_params += [('start', postvars.get('start', '-'))]
+        if site in {'todo', 'task', 'pick_tasks'}:
+            redir_params += [('search', postvars.get('search', ''))]
+            redir_params += [('search', postvars.get('search', ''))]
+            redir_params += [('search', postvars.get('search', ''))]
+        if postvars.has('filter'): 
+            postvars.set('return_to', '')
         
-        if parsed_url.path == app_config['prefix'] + '/calendar':
-            params_to_encode += [('start', postvars['start'][0] if len(postvars['start'][0]) > 0 else '-')]
-            params_to_encode += [('end', postvars['end'][0] if len(postvars['end'][0]) > 0 else '-')]
-
-        elif parsed_url.path == app_config['prefix'] + '/todo':
-            task_uuid = postvars['task_uuid'][0]
-            date = postvars['date'][0]
-            params_to_encode += [('task', task_uuid), ('date', date)]
-            db.update_todo(task_uuid, date, postvars['day_effort'][0], 'done' in postvars.keys(), postvars['comment'][0], postvars['joined_day_tags'][0], collect_checked('day_tag_', postvars), postvars['importance'][0])
-
-        elif parsed_url.path == app_config['prefix'] + '/task':
-            id_ = postvars['id'][0]
-            params_to_encode += [('id', id_)]
-            if 'title' in postvars.keys():
-                db.update_task(id_, postvars['title'][0], postvars['default_effort'][0], postvars['joined_tags'][0], collect_checked('tag_', postvars), collect_checked('link_', postvars))
-
-        elif parsed_url.path == app_config['prefix'] + '/day':
-            # always store the two hide params in the URL if possible … TODO: find out if really necessary
-            if 'expect_unchosen_done' in postvars.keys():
-                params_to_encode += [('hide_unchosen', int('hide_unchosen' in postvars.keys()))] + [('hide_done', int('hide_done' in postvars.keys()))]
-
-            if 'selected_date' in postvars.keys():
-                db.selected_date = postvars['selected_date'][0]
-                if 'day_comment' in postvars.keys():
-                    db.selected_day.comment = postvars['day_comment'][0]
-                params_to_encode += [('selected_date', db.selected_date)]
-
-                # handle todo list updates via task UUIDs
-                if 't_uuid' in postvars.keys():
-                    for i, uuid in enumerate(postvars['t_uuid']):
-                        task = db.tasks[uuid]
-                        old_todo = None if not uuid in db.selected_day.todos.keys() else db.selected_day.todos[uuid]
-                        selects_as_todo = 'choose' in postvars and uuid in postvars['choose']
-                        too_much_keepworthy_data = ('done' in postvars and uuid in postvars['done']) or postvars['day_effort'][i] != '' or (old_todo and not old_todo.internals_empty())
-                        if old_todo and too_much_keepworthy_data and not selects_as_todo:
-                            raise PlomException('cannot deselect task as todo of preserve-worthy values')
-                        elif old_todo and not selects_as_todo:
-                            del db.selected_day.todos[uuid]
+        if 'todo' == site:
+            todo_id = postvars.get('todo_id')
+            redir_params += [('id', todo_id)]
+            old_todo = db.todos[todo_id] if todo_id in db.todos.keys() else None
+            efforts = {}
+            for i, date in enumerate(postvars.get_all('effort_date', [])):
+                if '' == date:
+                    continue
+                try:
+                    datetime.strptime(date, DATE_FORMAT)
+                except ValueError:
+                    raise PlomException(f'bad date string')
+                efforts[date] = None
+                if not (old_todo and old_todo.children):
+                    efforts[date] = postvars.get_at_index('effort', i, None) 
+            if postvars.has('delete'): 
+                has_day_effort = len([e for e in efforts.values() if e is not None]) > 0
+                if postvars.has('done')\
+                        or postvars.get('comment')\
+                        or len(postvars.get_defined_tags('joined_day_tags', 'day_tag_')) > 0\
+                        or has_day_effort:
+                    raise PlomException('will not remove todo of preserve-worthy values')
+                db.delete_todo(todo_id) 
+                if not postvars.get('return_to'):
+                    postvars.set('return_to', 'calendar')
+            elif postvars.has('update'):
+                if postvars.has('delete_effort'):
+                    for date in postvars.get_all('delete_effort'):
+                        db.delete_effort(old_todo, date)
+                        del efforts[date]
+                children = [db.todos[id_] for id_ in postvars.get_all('adopt_child', [])] 
+                db.update_todo(id_=todo_id,
+                               efforts=efforts,
+                               done=postvars.has('done'),
+                               comment=postvars.get('comment', ''),
+                               tags=postvars.get_defined_tags('joined_day_tags', 'day_tag_'),
+                               importance=float(postvars.get('importance')),
+                               children=children)
+
+        elif 'task' == site:
+            task_id = postvars.get('task_id')
+            if postvars.has('update'):
+                db.update_task(
+                        id_=task_id,
+                        title=postvars.get('title', ''),
+                        default_effort=postvars.get_float_if_possible('default_effort'), 
+                        tags=postvars.get_defined_tags('joined_tags', 'tag_'),
+                        subtask_ids=postvars.get_all('subtask', []),
+                        comment=postvars.get('comment', ''))
+            redir_params += [('id', task_id)]
+
+        elif 'pick_tasks' == site:
+            redir_params += [('hide_chosen_tasks', int(postvars.has('hide_chosen_tasks')))]
+            if postvars.has('update'):
+                db.selected_date = postvars.get('date')
+                todos_to_shrink = []
+                todos_to_delete = []
+                for todo in db.selected_day.linked_todos_as_list:
+                    if todo.visible and not todo.id_ in postvars.get_all('chosen_todo', []):
+                        if len(todo.comment) > 0\
+                                or len(todo.day_tags) > 0\
+                                or not todo.is_effort_removable(db.selected_date):
+                            raise PlomException('will not remove effort of preserve-worthy values')
+                        if len(todo.efforts) > 1:
+                            todos_to_shrink += [todo]
                         else:
-                            done = ('done' in postvars) and (uuid in postvars['done'])
-                            day_effort_input = postvars['day_effort'][i]
-                            day_effort = float(day_effort_input) if len(day_effort_input) > 0 else None
-                            importance = float(postvars['importance'][i])
-                            if old_todo and old_todo.done == done and old_todo.day_effort == day_effort and old_todo.importance == importance:
-                                continue
-                            db.update_todo_mini(uuid, db.selected_date, day_effort, done, importance)
-
-        if 'referer' in postvars.keys() and len(postvars['referer'][0]) > 0:
-            homepage = postvars['referer'][0]
-        else:
-            encoded_params = urlencode(params_to_encode)
-            homepage = f'{parsed_url.path}?{encoded_params}'
+                            todos_to_delete += [todo]
+                for todo in todos_to_shrink:
+                    db.delete_effort(todo, db.selected_date)
+                for todo in todos_to_delete:
+                    db.delete_todo(todo.id_)
+                for id_ in postvars.get_all('choose_task', []):
+                    db.add_todo(task=db.tasks[id_], efforts={db.selected_date: None})
+                for id_ in postvars.get_all('choose_todo', []):
+                    db.todos[id_].efforts[db.selected_date] = None
+
+        elif 'do_todos' == site:
+            redir_params += [('hide_done', int(postvars.has('hide_done')))]
+            if postvars.has('update'): 
+                db.selected_date = postvars.get('date') 
+                redir_params += [('date', db.selected_date)]
+                db.selected_day.comment = postvars.get('day_comment', '') 
+                for i, todo_id in enumerate(postvars.get_all('todo_id')):
+                    old_todo = None if not todo_id in db.todos.keys() else db.todos[todo_id]
+                    done = todo_id in postvars.get_all('done', [])
+                    day_effort_input = postvars.get_at_index('effort', i, '') 
+                    day_effort = float(day_effort_input) if len(day_effort_input) > 0 else None
+                    comment = postvars.get_at_index('effort_comment', i, '') 
+                    importance = float(postvars.get_at_index('importance', i))
+                    if old_todo\
+                            and old_todo.done == done\
+                            and old_todo.day_effort == day_effort\
+                            and comment == old_todo.comment\
+                            and old_todo.importance == importance:
+                        continue
+                    db.update_todo_for_day(
+                            todo_id,
+                            db.selected_date,
+                            day_effort,
+                            done,
+                            comment,
+                            importance)
+
+        homepage = postvars.get('return_to')
+        if not homepage:
+            encoded_params = urlencode(redir_params)
+            homepage = f'{site}?{encoded_params}'
         db.write()
         self.redirect(homepage)
 
     def do_GET(self):
-        self.try_do(self.config_init)
         self.try_do(self.show_db)
 
     def show_db(self):
-        app_config = self.apps['todo'] if hasattr(self, 'apps') else self.config()
-        cookie_db = self.get_cookie_db(app_config['cookie_name'])
+        config = self.apps['todo'] if hasattr(self, 'apps') else self.config_init()
         parsed_url = urlparse(self.path)
-        params = parse_qs(parsed_url.query)
-
-        def get_param(param_name, boolean=False, chained=False):
-            if chained:
-                param = params.get(param_name, None)
-            else:
-                param = params.get(param_name, [None])[0]
-            if (not chained and param == '-') or (chained and param == ['-']):
-                param = None
-                if param_name in cookie_db.keys():
-                    del cookie_db[param_name]
-            if param is None and param_name in cookie_db.keys():
-                param = cookie_db[param_name]
-            if param is not None:
-                if boolean:
-                    param = param != '0'
-                    cookie_db[param_name] = str(int(param))
-                else:
-                    cookie_db[param_name] = param
-            elif param is boolean:
-                param = False
-            return param
+        site = path_split(parsed_url.path)[1]
+        cookie_db = self.get_cookie_db(config['cookie_name'])
+        params = ParamsParser(parsed_url.query, cookie_db)
 
         selected_date = t_filter_and = t_filter_not = None
         hide_unchosen = hide_done = False
-        referer = params.get('referer', [''])[0]
-        if parsed_url.path in {app_config['prefix'] + '/day', app_config['prefix'] + '/tasks'}:
-            selected_date = get_param('selected_date')
-        if parsed_url.path in {app_config['prefix'] + '/day', app_config['prefix'] + '/tasks', app_config['prefix'] + '/task'}:
-            t_filter_and = get_param('t_and', chained=True)
-            t_filter_not = get_param('t_not', chained=True)
-        if parsed_url.path == app_config['prefix'] + '/day':
-            hide_unchosen = get_param('hide_unchosen', boolean=True)
-            hide_done = get_param('hide_done', boolean=True)
-        db = TodoDB(app_config['prefix'], selected_date, t_filter_and, t_filter_not, hide_unchosen, hide_done)
-        if parsed_url.path == app_config['prefix'] + '/day':
-            task_sort = get_param('sort')
-            page = db.show_day(task_sort)
-        elif parsed_url.path == app_config['prefix'] + '/todo':
-            todo_date = params.get('date', [None])[0]
-            task_uuid = params.get('task', [None])[0]
-            page = db.show_todo(task_uuid, todo_date, referer)
-        elif parsed_url.path == app_config['prefix'] + '/task':
-            id_ = params.get('id', [None])[0]
-            page = db.show_task(id_, referer)
-        elif parsed_url.path == app_config['prefix'] + '/tasks':
-            page = db.show_tasks()
-        elif parsed_url.path == app_config['prefix'] + '/add_task':
+        return_to = params.get('return_to', '')
+        if site in {'do_todos', 'pick_tasks', 'calendar'}:
+            selected_date = params.get_cookied('date')
+        if site in {'do_todos', 'pick_tasks', 'task', 'todo'}:
+            t_filter_and = params.get_cookied_chain('t_and')
+            t_filter_not = params.get_cookied_chain('t_not')
+        if 'do_todos' == site:
+            hide_done = params.get('hide_done', False) 
+        db = TodoDB(config['prefix'], selected_date, t_filter_and, t_filter_not, hide_unchosen, hide_done)
+        if site in {'todo', 'task'}:
+            id_ = params.get('id')
+        if site in {'todo', 'task', 'pick_tasks'}:
+            search = params.get('search', '')
+        if site in {'do_todos', 'pick_tasks'}:
+            sort_order = params.get_cookied('sort')
+        if site in {'calendar', 'todo'}:
+            start_date = params.get_cookied('start')
+            end_date = params.get_cookied('end')
+        if 'do_todos' == site:
+            page = db.show_do_todos(sort_order)
+        elif 'pick_tasks' == site:
+            hide_chosen_tasks = params.get('hide_chosen_tasks', False)
+            page = db.show_pick_tasks(search, hide_chosen_tasks, sort_order)
+        elif site == 'todo':
+            page = db.show_todo(id_, return_to, search, start_date, end_date)
+        elif 'task' == site:
+            page = db.show_task(id_, return_to, search)
+        elif 'tasks' == site:
+            expand_uuid = params.get('expand_uuid')
+            page = db.show_tasks(expand_uuid)
+        elif 'add_task' == site:
             page = db.show_task(None)
-        elif parsed_url.path == app_config['prefix'] + '/unset_cookie':
+        elif 'unset_cookie' == site:
             page = 'no cookie to unset.'
             if len(cookie_db) > 0:
-                self.unset_cookie(app_config['cookie_name'], app_config['cookie_path'])
+                self.unset_cookie(config['cookie_name'], config['cookie_path'])
                 page = 'cookie unset!'
         else:
-            start_date = get_param('start')
-            start_date = start_date if start_date else 'today'
-            end_date = get_param('end')
             page = db.show_calendar(start_date, end_date)
-        if parsed_url.path != app_config['prefix'] + '/unset_cookie':
-            self.set_cookie(app_config['cookie_name'], app_config['cookie_path'], cookie_db)
+
+        if 'unset_cookie' != site:
+            self.set_cookie(config['cookie_name'], config['cookie_path'], cookie_db)
         self.send_HTML(page)