X-Git-Url: https://plomlompom.com/repos/berlin_corona.txt?a=blobdiff_plain;f=ledger.py;h=2b2a80764104057ccf3e03ef62a29ecd291c15b1;hb=fb98793f5731cb56c3122ce813ea85158040abed;hp=27675da2778e2d7cd94c0354fa7c93848b6eef05;hpb=255b10fbe4b0c688828d510868017565af50b57f;p=misc

diff --git a/ledger.py b/ledger.py
index 27675da..2b2a807 100755
--- a/ledger.py
+++ b/ledger.py
@@ -1,8 +1,9 @@
 from http.server import BaseHTTPRequestHandler, HTTPServer
-import sys
 import os
 import html
-import jinja2 
+import jinja2
+import decimal
+import datetime
 from urllib.parse import parse_qs, urlparse
 hostName = "localhost"
 serverPort = 8082
@@ -12,11 +13,6 @@ class HandledException(Exception):
     pass
 
 
-def handled_error_exit(msg):
-    print(f"ERROR: {msg}")
-    sys.exit(1)
-
-
 def apply_booking_to_account_balances(account_sums, account, currency, amount):
     if not account in account_sums:
         account_sums[account] = {currency: amount}
@@ -26,60 +22,6 @@ def apply_booking_to_account_balances(account_sums, account, currency, amount):
         account_sums[account][currency] += amount
 
 
-def add_taxes(lines):
-    import decimal
-    bookings, _ = parse_lines(lines)
-    _, account_sums = bookings_to_account_tree(bookings)
-    expenses_so_far = -1 * account_sums['Assets']['€']
-    needed_income_before_krankenkasse = expenses_so_far
-    ESt_this_month = 0
-    left_over = needed_income_before_krankenkasse - ESt_this_month
-    too_low = 0
-    too_high = 2 * needed_income_before_krankenkasse 
-    E0 = 10908
-    E1 = 15999 
-    E2 = 62809 
-    E3 = 277825 
-    while True:
-        zvE = 12 * needed_income_before_krankenkasse
-        if zvE < E0:
-            ESt = decimal.Decimal(0)
-        elif zvE < E1:
-            y = (zvE - E0)/10000
-            ESt = (decimal.Decimal(979.18) * y + 1400) * y
-        elif zvE < E2:
-            y = (zvE - E1)/10000
-            ESt = (decimal.Decimal(192.59) * y + 2397) * y + decimal.Decimal(966.53)
-        elif zvE < E3:
-            ESt = decimal.Decimal(0.42) * (zvE - decimal.Decimal(62809))  + decimal.Decimal(16405.54)
-        else: 
-            ESt = decimal.Decimal(0.45) * (zvE - decimal.Decimal(277825)) + decimal.Decimal(106713.52) 
-        ESt_this_month = ESt / 12
-        left_over = needed_income_before_krankenkasse - ESt_this_month
-        if abs(left_over - expenses_so_far) < 0.1:
-            break
-        elif left_over < expenses_so_far:
-            too_low = needed_income_before_krankenkasse
-        elif left_over > expenses_so_far:
-            too_high = needed_income_before_krankenkasse
-        needed_income_before_krankenkasse = too_low + (too_high - too_low)/2
-    line_income_tax = f'  Reserves:Einkommenssteuer  {ESt_this_month:.2f}€ ; expenses so far: {expenses_so_far:.2f}€; zvE: {zvE:.2f}€; ESt total: {ESt:.2f}€; needed before Krankenkasse: {needed_income_before_krankenkasse:.2f}€'
-    kk_minimum_income = 1096.67 
-    kk_factor = decimal.Decimal(0.189) 
-    kk_minimum_tax = decimal.Decimal(207.27)
-    # kk_minimum_income = 1131.67 
-    # kk_factor = decimal.Decimal(0.191) 
-    # kk_minimum_tax = decimal.Decimal(216.15)
-    # kk_factor = decimal.Decimal(0.197) 
-    # kk_minimum_tax = decimal.Decimal(222.94)
-    kk_add = max(0, kk_factor * needed_income_before_krankenkasse - kk_minimum_tax)
-    line_kk_minimum = f'  Reserves:Month:Krankenkassendefaultbeitrag  {kk_minimum_tax:.2f}€  ; assed minimum income {kk_minimum_income:.2f}€ * {kk_factor:.3f}'
-    line_kk_add = f'  Reserves:Month:Krankenkassenbeitragswachstum {kk_add:.2f}€  ; max(0, {kk_factor:.3f} * {needed_income_before_krankenkasse:.2f}€ - {kk_minimum_tax:.2f}€)'
-    final_minus = expenses_so_far + ESt_this_month + kk_minimum_tax + kk_add 
-    line_finish = f'  Assets  -{final_minus:.2f}€'
-    return [line_income_tax, line_kk_minimum, line_kk_add, line_finish]
-
-
 def bookings_to_account_tree(bookings):
     account_sums = {}
     for booking in bookings:
@@ -124,9 +66,8 @@ def bookings_to_account_tree(bookings):
     return account_tree, account_sums
 
 
-def parse_lines(lines):
+def parse_lines(lines, validate_bookings=True):
     import datetime
-    import decimal
     inside_booking = False
     date_string, description = None, None
     booking_lines = []
@@ -134,6 +75,7 @@ def parse_lines(lines):
     bookings = []
     comments = []
     lines = lines.copy() + [''] # to ensure a booking-ending last line
+    last_date = ''
     for i, line in enumerate(lines):
         prefix = f"line {i}"
         # we start with the case of an utterly empty line
@@ -144,7 +86,7 @@ def parse_lines(lines):
                 # assume we finished a booking, finalize, and commit to DB
                 if len(booking_lines) < 2:
                     raise HandledException(f"{prefix} booking ends to early")
-                booking = Booking(date_string, description, booking_lines, start_line)
+                booking = Booking(date_string, description, booking_lines, start_line, validate_bookings)
                 bookings += [booking]
             # expect new booking to follow so re-zeroall booking data
             inside_booking = False
@@ -170,6 +112,9 @@ def parse_lines(lines):
                 datetime.datetime.strptime(date_string, '%Y-%m-%d')
             except ValueError:
                 raise HandledException(f"{prefix} bad date string: {date_string}")
+            if last_date > date_string:
+                raise HandledException(f"{prefix} out-of-order-date")
+            last_date = date_string
             try:
                 description = toks[1]
             except IndexError:
@@ -235,11 +180,10 @@ def parse_lines(lines):
                             raise HandledException(f"{prefix} amount has multiple dots: {value}")
                         dots_counted += 1
                     amount_string += c
-            if len(amount_string) == 0:
-                raise HandledException(f"{prefix} amount missing: {value}")
             if len(currency) == 0:
                 raise HandledException(f"{prefix} currency missing: {value}")
-            amount = decimal.Decimal(amount_string)
+            if len(amount_string) > 0:
+                amount = decimal.Decimal(amount_string)
         booking_lines += [(account_name, amount, currency)]
     if inside_booking:
         raise HandledException(f"{prefix} last booking unfinished")
@@ -248,13 +192,15 @@ def parse_lines(lines):
 
 class Booking:
 
-    def __init__(self, date_string, description, booking_lines, start_line):
+    def __init__(self, date_string, description, booking_lines, start_line, process=True):
         self.date_string = date_string
         self.description = description
         self.lines = booking_lines
         self.start_line = start_line
-        self.validate_booking_lines()
-        self.account_changes = self.parse_booking_lines_to_account_changes()
+        if process:
+            self.validate_booking_lines()
+            self.sink = {}
+            self.account_changes = self.parse_booking_lines_to_account_changes()
 
     def validate_booking_lines(self):
         prefix = f"booking at line {self.start_line}"
@@ -275,7 +221,7 @@ class Booking:
         if empty_values == 0:
             for k, v in sums.items():
                 if v != 0:
-                    raise HandledException(f"{prefix} does not sum up to zero")
+                    raise HandledException(f"{prefix} does not add up to zero / {k} {v}")
         else:
             sinkable = False
             for k, v in sums.items():
@@ -303,6 +249,7 @@ class Booking:
         if sink_account:
             for currency, amount in debt.items():
                 apply_booking_to_account_balances(account_changes, sink_account, currency, -amount)
+                self.sink[currency] = -amount
         return account_changes
 
 
@@ -326,31 +273,175 @@ class Database:
     def get_lines(self, start, end):
         return self.real_lines[start:end]
 
-    def replace(self, start, end, lines):
+    def write_db(self, text, mode='w'):
         import shutil
         if os.path.exists(self.lock_file):
             raise HandledException('Sorry, lock file!')
-        if os.path.exists(self.db_file):
-            shutil.copy(self.db_file, self.db_file + ".bak")
         f = open(self.lock_file, 'w+')
         f.close()
-        total_lines = self.real_lines[:start] + lines + self.real_lines[end:]
-        text = '\n'.join(total_lines)
-        with open(self.db_file, 'w') as f:
+
+        # always back up most recent to .bak
+        bakpath = f'{self.db_file}.bak'
+        shutil.copy(self.db_file, bakpath)
+
+        # collect modification times of numbered .bak files
+        bak_prefix = f'{bakpath}.'
+        backup_dates = []
+        i = 0
+        bak_as = f'{bak_prefix}{i}'
+        while os.path.exists(bak_as):
+            mod_time = os.path.getmtime(bak_as)
+            backup_dates += [str(datetime.datetime.fromtimestamp(mod_time))]
+            i += 1
+            bak_as = f'{bak_prefix}{i}'
+
+        # collect what numbered .bak files to save
+        to_save = []
+        datetime_len = 19
+        now = str(datetime.datetime.now())[:datetime_len]
+        while datetime_len > 2:
+            for i, date in reversed(list(enumerate(backup_dates))):
+                if date[:datetime_len] == now:
+                    if i not in to_save:
+                        to_save += [i] 
+                        break
+            datetime_len -= 1 
+            now = now[:datetime_len]
+
+        # remove redundant backup files 
+        j = 0
+        for i in reversed(to_save):
+            if i != j:
+                source = f'{bak_prefix}{i}'
+                target = f'{bak_prefix}{j}'
+                shutil.move(source, target)
+            j += 1
+        for i in range(j, len(backup_dates)):
+            try:
+                os.remove(f'{bak_prefix}{i}')
+            except FileNotFoundError:
+                pass
+
+        # 
+        shutil.copy(self.db_file, f'{bak_prefix}{j}')
+        with open(self.db_file, mode) as f:
             f.write(text);
         os.remove(self.lock_file)
 
+    def replace(self, start, end, lines):
+        total_lines = self.real_lines[:start] + lines + self.real_lines[end:]
+        text = '\n'.join(total_lines)
+        self.write_db(text)
+
     def append(self, lines):
-        import shutil
-        if os.path.exists(self.lock_file):
-            raise HandledException('Sorry, lock file!')
-        if os.path.exists(self.db_file):
-            shutil.copy(self.db_file, self.db_file + ".bak")
-        f = open(self.lock_file, 'w+')
-        f.close()
-        with open(self.db_file, 'a') as f:
-            f.write('\n\n' + '\n'.join(lines) + '\n\n');
-        os.remove(self.lock_file)
+        text = '\n\n' + '\n'.join(lines) + '\n\n'
+        self.write_db(text, 'a')
+
+    def add_taxes(self, lines, finish=False):
+        ret = []
+        bookings, _ = parse_lines(lines)
+        date = bookings[0].date_string
+        acc_kk_add = 'Reserves:KrankenkassenBeitragsWachstum'
+        acc_kk_minimum = 'Reserves:Month:KrankenkassenDefaultBeitrag'
+        acc_kk = 'Expenses:KrankenKasse'
+        acc_est = 'Reserves:Einkommenssteuer'
+        acc_assets = 'Assets'
+        acc_buffer = 'Reserves:NeuAnfangsPuffer:Ausgaben'
+        last_monthbreak_assets = 0
+        last_monthbreak_est = 0
+        last_monthbreak_kk_minimum = 0
+        last_monthbreak_kk_add = 0
+        buffer_expenses = 0
+        kk_expenses = 0
+        est_expenses = 0
+        months_passed = -int(finish) 
+        for b in self.bookings:
+            if date == b.date_string:
+                break
+            acc_keys = b.account_changes.keys()
+            if acc_buffer in acc_keys:
+                buffer_expenses -= b.account_changes[acc_buffer]['€']
+            if acc_kk_add in acc_keys:
+                kk_expenses += b.account_changes[acc_kk_add]['€']
+            if acc_kk in acc_keys:
+                kk_expenses += b.account_changes[acc_kk]['€']
+            if acc_est in acc_keys:
+                est_expenses += b.account_changes[acc_est]['€']
+            if acc_kk_add in acc_keys and acc_kk_minimum in acc_keys:
+                months_passed += 1
+                if finish:
+                    last_monthbreak_kk_add = b.account_changes[acc_kk_add]['€']
+                    last_monthbreak_est = b.account_changes[acc_est]['€']
+                    last_monthbreak_kk_minimum = b.account_changes[acc_kk_minimum]['€']
+                    last_monthbreak_assets = b.account_changes[acc_buffer]['€']
+        old_needed_income = last_monthbreak_assets + last_monthbreak_kk_add + last_monthbreak_kk_minimum + last_monthbreak_est
+        if finish:
+            ret += [f'  {acc_est}  {-last_monthbreak_est}€ ; for old assumption of needed income: {old_needed_income}€']
+        _, account_sums = bookings_to_account_tree(bookings)
+        expenses_so_far = -1 * account_sums[acc_assets]['€'] - old_needed_income
+        needed_income_before_kk = expenses_so_far
+        ESt_this_month = 0
+        left_over = needed_income_before_kk - ESt_this_month
+        too_low = 0
+        too_high = 2 * needed_income_before_kk
+        E0 = decimal.Decimal(10908)
+        E1 = decimal.Decimal(15999)
+        E2 = decimal.Decimal(62809)
+        E3 = decimal.Decimal(277825)
+        while True:
+            zvE = buffer_expenses - kk_expenses + (12 - months_passed) * needed_income_before_kk
+            if finish:
+                zvE += last_monthbreak_assets + last_monthbreak_kk_add + last_monthbreak_kk_minimum
+            if zvE < E0:
+                ESt = decimal.Decimal(0)
+            elif zvE < E1:
+                y = (zvE - E0)/10000
+                ESt = (decimal.Decimal(979.18) * y + 1400) * y
+            elif zvE < E2:
+                y = (zvE - E1)/10000
+                ESt = (decimal.Decimal(192.59) * y + 2397) * y + decimal.Decimal(966.53)
+            elif zvE < E3:
+                ESt = decimal.Decimal(0.42) * (zvE - decimal.Decimal(62809))  + decimal.Decimal(16405.54)
+            else:
+                ESt = decimal.Decimal(0.45) * (zvE - decimal.Decimal(277825)) + decimal.Decimal(106713.52)
+            ESt_this_month = (ESt + last_monthbreak_est - est_expenses) / (12 - months_passed)
+            left_over = needed_income_before_kk - ESt_this_month
+            if abs(left_over - expenses_so_far) < 0.001:
+                break
+            elif left_over < expenses_so_far:
+                too_low = needed_income_before_kk
+            elif left_over > expenses_so_far:
+                too_high = needed_income_before_kk
+            needed_income_before_kk = too_low + (too_high - too_low)/2
+        ESt_this_month = ESt_this_month.quantize(decimal.Decimal('0.00'))
+        ret += [f'  {acc_est}  {ESt_this_month}€ ; expenses so far: {expenses_so_far:.2f}€; zvE: {zvE:.2f}€; ESt total: {ESt:.2f}€; needed before Krankenkasse: {needed_income_before_kk:.2f}€']
+        kk_minimum_income = 1131.67
+        if date < '2023-02-01':
+            kk_minimum_income = decimal.Decimal(1096.67)
+            kk_factor = decimal.Decimal(0.189)
+            kk_minimum_tax = decimal.Decimal(207.27).quantize(decimal.Decimal('0.00'))
+        elif date < '2023-08-01':
+            kk_factor = decimal.Decimal(0.191)
+            kk_minimum_tax = decimal.Decimal(216.15).quantize(decimal.Decimal('0.00'))
+        else:
+            kk_factor = decimal.Decimal(0.197)
+            kk_minimum_tax = decimal.Decimal(222.94).quantize(decimal.Decimal('0.00'))
+        kk_add = max(0, kk_factor * needed_income_before_kk - kk_minimum_tax)
+        kk_add = decimal.Decimal(kk_add).quantize(decimal.Decimal('0.00'))
+        if finish:
+            ret += [f'  {acc_kk_add}  {-last_monthbreak_kk_add}€  ; max(0, {kk_factor:.3f} * {-(old_needed_income - last_monthbreak_est):.2f}€ - {kk_minimum_tax}€)']
+        else:
+            ret += [f'  {acc_kk_minimum}  {kk_minimum_tax}€  ; assumed minimum income {kk_minimum_income:.2f}€ * {kk_factor:.3f}']
+        ret += [f'  {acc_kk_add}  {kk_add}€  ; max(0, {kk_factor:.3f} * {needed_income_before_kk:.2f}€ - {kk_minimum_tax}€)']
+        diff = - last_monthbreak_est + ESt_this_month - last_monthbreak_kk_add + kk_add
+        if not finish:
+            diff += kk_minimum_tax
+        final_minus = expenses_so_far + old_needed_income + diff
+        ret += [f'  {acc_assets}  {-diff} €']
+        ret += [f'  {acc_assets}  {final_minus} €']
+        year_needed = buffer_expenses + final_minus + (12 - months_passed - 1) * final_minus 
+        ret += [f'  {acc_buffer}  {-final_minus} € ; assume as to earn in year: {acc_buffer} + {12 - months_passed - 1} * this = {-year_needed}']
+        return ret
 
 
 class MyServer(BaseHTTPRequestHandler):
@@ -363,109 +454,166 @@ th, td { text-align: left }
 input[type=number] { text-align: right; font-family: monospace; }
 .money { font-family: monospace; text-align: right; }
 .comment { font-style: italic; color: #777777; }
+.meta { font-size: 0.75em; color: #777777; }
 .full_line_comment { display: block; white-space: nowrap; width: 0; }
 </style>
 <body>
-<a href="/ledger">ledger</a>
+<a href="/">ledger</a>
 <a href="/balance">balance</a>
 <a href="/add_free">add free</a>
 <a href="/add_structured">add structured</a>
 <hr />
+"""
+    booking_tmpl = jinja2.Template("""
+<p id="{{nth}}"><a href="#{{nth}}">{{date}}</a> {{desc}} <span class="comment">{{head_comment|e}}</span><br />
+<span class="meta">[edit: <a href="/add_structured?start={{start}}&end={{end}}">structured</a>
+/ <a href="/add_free?start={{start}}&end={{end}}">free</a>
+| copy:<a href="/copy_structured?start={{start}}&end={{end}}">structured</a>
+/ <a href="/copy_free?start={{start}}&end={{end}}">free</a>
+| <a href="/balance?stop={{nth+1}}">balance after</a>
+]</span>
+<table>
+{% for l in booking_lines %}
+{% if l.acc %}
+<tr><td>{{l.acc|e}}</td><td class="money">{{l.money|e}}</td><td class="comment">{{l.comment|e}}</td></tr>
+{% else %}
+<tr><td><div class="comment full_line_comment">{{l.comment|e}}</div></td></tr>
+{% endif %}
+{% endfor %}
+</table></p>
+""")
+    add_form_footer = """
+<input type="hidden" name="start" value={{start}} />
+<input type="hidden" name="end" value={{end}} />
+<input type="submit" name="save" value="save!">
+</form>
 """
     footer = "</body>\n<html>"
 
     def do_POST(self):
-        db = Database()
-        length = int(self.headers['content-length'])
-        postvars = parse_qs(self.rfile.read(length).decode(), keep_blank_values=1)
-        parsed_url = urlparse(self.path)
-        lines = []
-        add_empty_line = None 
-        if '/add_structured' == parsed_url.path and not 'revert' in postvars.keys():
-            date = postvars['date'][0]
-            description = postvars['description'][0]
-            start_comment = postvars['line_0_comment'][0]
-            lines = [f'{date} {description} ; {start_comment}']
-            if 'line_0_add' in postvars.keys():
-                add_empty_line = 0
-            i = j = 1
-            while f'line_{i}_comment' in postvars.keys():
-                if f'line_{i}_delete' in postvars.keys():
-                    i += 1
-                    continue
-                if f'line_{i}_add' in postvars.keys():
-                    add_empty_line = j
-                account = postvars[f'line_{i}_account'][0]
-                amount = postvars[f'line_{i}_amount'][0]
-                currency = postvars[f'line_{i}_currency'][0]
-                comment = postvars[f'line_{i}_comment'][0]
-                i += 1
-                new_main = f'{account} {amount} {currency}'
-                if '' == new_main.rstrip() == comment.rstrip():  # don't write empty lines
-                    continue
-                j += 1
-                new_line = new_main
-                if comment.rstrip() != '':
-                    new_line += f' ; {comment}'
-                lines += [new_line]
-            if 'add_taxes' in postvars.keys():
-                lines += add_taxes(lines)
-        elif '/add_free' == parsed_url.path:
-            lines = postvars['booking'][0].splitlines()
-        start = int(postvars['start'][0])
-        end = int(postvars['end'][0])
         try:
-            _, _ = parse_lines(lines)
+            parsed_url = urlparse(self.path)
+            length = int(self.headers['content-length'])
+            postvars = parse_qs(self.rfile.read(length).decode(), keep_blank_values=1)
+            start = int(postvars['start'][0])
+            end = int(postvars['end'][0])
+
+            db = Database()
+            add_empty_line = None
+            lines = []
+            if '/add_structured' == parsed_url.path and not 'revert' in postvars.keys():
+                date = postvars['date'][0]
+                description = postvars['description'][0]
+                start_comment = postvars['line_0_comment'][0]
+                lines = [f'{date} {description} ; {start_comment}']
+                if 'line_0_add' in postvars.keys():
+                    add_empty_line = 0
+                i = j = 1
+                while f'line_{i}_comment' in postvars.keys():
+                    if f'line_{i}_delete' in postvars.keys():
+                        i += 1
+                        continue
+                    elif f'line_{i}_delete_after' in postvars.keys():
+                        break 
+                    elif f'line_{i}_add' in postvars.keys():
+                        add_empty_line = j
+                    account = postvars[f'line_{i}_account'][0]
+                    amount = postvars[f'line_{i}_amount'][0]
+                    currency = postvars[f'line_{i}_currency'][0]
+                    comment = postvars[f'line_{i}_comment'][0]
+                    i += 1
+                    new_main = f'  {account}  {amount}'
+                    if '' == new_main.rstrip() == comment.rstrip():  # don't write empty lines, ignore currency if nothing else set
+                        continue
+                    if len(amount.rstrip()) > 0:
+                        new_main += f' {currency}'
+                    j += 1
+                    new_line = new_main
+                    if comment.rstrip() != '':
+                        new_line += f'  ; {comment}'
+                    lines += [new_line]
+                if 'add_sink' in postvars.keys():
+                    temp_lines = lines.copy() + ['_']
+                    try:
+                        temp_bookings, _ = parse_lines(temp_lines)
+                        for currency in temp_bookings[0].sink:
+                            amount = temp_bookings[0].sink[currency]
+                            lines += [f'Assets  {amount:.2f} {currency}']
+                    except HandledException:
+                        pass
+                if 'add_taxes' in postvars.keys():
+                    lines += db.add_taxes(lines, finish=False)
+                elif 'add_taxes2' in postvars.keys():
+                    lines += db.add_taxes(lines, finish=True)
+            elif '/add_free' == parsed_url.path:
+                lines = postvars['booking'][0].splitlines()
+
+            if ('save' in postvars.keys()) or ('check' in postvars.keys()):
+                _, _ = parse_lines(lines)
+
             if 'save' in postvars.keys():
                 if start == end == 0:
                     db.append(lines)
+                    redir_url = f'/#last'
                 else:
                     db.replace(start, end, lines)
-                self.send_response(301)
-                redir_url = '/'
-                self.send_header('Location', redir_url)
-                self.end_headers()
-            else:
+                    nth = 0
+                    for i, b in enumerate(db.bookings):
+                        if b.start_line == start:
+                            nth = i
+                            break
+                    redir_url = f'/#{nth}'
+                self.send_code_and_headers(301, [('Location', redir_url)])
+            else:  # implicit assumption: this only happens on /add_structured flows
                 page = self.header + self.add_structured(db, start, end, temp_lines=lines, add_empty_line=add_empty_line) + self.footer
-                self.send_response(200)
-                self.send_header("Content-type", "text/html")
-                self.end_headers()
-                self.wfile.write(bytes(page, "utf-8"))
+                self.send_HTML(page)
         except HandledException as e:
-            self.send_response(400)
-            self.send_header("Content-type", "text/html")
-            self.end_headers()
-            page = f'{self.header}ERROR: {e}{self.footer}'
-            self.wfile.write(bytes(page, "utf-8"))
+            self.fail_400(e)
 
     def do_GET(self):
-        self.send_response(200)
-        self.send_header("Content-type", "text/html")
+        try:
+            parsed_url = urlparse(self.path)
+            params = parse_qs(parsed_url.query)
+            start = int(params.get('start', ['0'])[0])
+            end = int(params.get('end', ['0'])[0])
+            db = Database()
+            page = self.header
+            if parsed_url.path == '/balance':
+                stop = params.get('stop', [None])[0]
+                page += self.balance_as_html(db, stop)
+            elif parsed_url.path == '/add_free':
+                page += self.add_free(db, start, end)
+            elif parsed_url.path == '/add_structured':
+                page += self.add_structured(db, start, end)
+            elif parsed_url.path == '/copy_free':
+                page += self.add_free(db, start, end, copy=True)
+            elif parsed_url.path == '/copy_structured':
+                page += self.add_structured(db, start, end, copy=True)
+            else:
+                page += self.ledger_as_html(db)
+            page += self.footer
+            self.send_HTML(page)
+        except HandledException as e:
+            self.fail_400(e)
+
+    def fail_400(self, e):
+        page = f'{self.header}ERROR: {e}{self.footer}'
+        self.send_HTML(page, 400)
+
+    def send_HTML(self, html, code=200):
+        self.send_code_and_headers(code, [('Content-type', 'text/html')])
+        self.wfile.write(bytes(html, "utf-8"))
+
+    def send_code_and_headers(self, code, headers=[]):
+        self.send_response(code)
+        for fieldname, content in headers:
+            self.send_header(fieldname, content)
         self.end_headers()
-        db = Database()
-        parsed_url = urlparse(self.path)
-        page = self.header + ''
-        params = parse_qs(parsed_url.query)
-        start = int(params.get('start', ['0'])[0])
-        end = int(params.get('end', ['0'])[0])
-        if parsed_url.path == '/balance':
-            page += self.balance_as_html(db)
-        elif parsed_url.path == '/add_free':
-            page += self.add_free(db, start, end)
-        elif parsed_url.path == '/add_structured':
-            page += self.add_structured(db, start, end)
-        elif parsed_url.path == '/copy_free':
-            page += self.add_free(db, start, end, copy=True)
-        elif parsed_url.path == '/copy_structured':
-            page += self.add_structured(db, start, end, copy=True)
-        else:
-            page += self.ledger_as_html(db)
-        page += self.footer
-        self.wfile.write(bytes(page, "utf-8"))
 
-    def balance_as_html(self, db):
+    def balance_as_html(self, db, until=None):
+        bookings = db.bookings[:until if until is None else int(until)]
         lines = []
-        account_tree, account_sums = bookings_to_account_tree(db.bookings)
+        account_tree, account_sums = bookings_to_account_tree(bookings)
         def print_subtree(lines, indent, node, subtree, path):
             line = f"{indent}{node}"
             n_tabs = 5 - (len(line) // 8)
@@ -488,66 +636,48 @@ input[type=number] { text-align: right; font-family: monospace; }
         return f"<pre>{content}</pre>"
 
     def ledger_as_html(self, db):
-        single_c_tmpl = jinja2.Template('<span class="comment">{{c|e}}</span><br />')
-        booking_tmpl = jinja2.Template("""
-<p>{{date}} {{desc}} <span class="comment">{{head_comment|e}}</span>
-[edit: <a href="/add_structured?start={{start}}&end={{end}}">structured</a> 
-/ <a href="/add_free?start={{start}}&end={{end}}">free</a> 
-| copy:<a href="/copy_structured?start={{start}}&end={{end}}">structured</a>
-/ <a href="/copy_free?start={{start}}&end={{end}}">free</a>]
-<table>
-{% for l in booking_lines %}
-{% if l.acc %}
-<tr><td>{{l.acc|e}}</td><td class="money">{{l.money|e}}</td><td class="comment">{{l.comment|e}}</td></tr>
-{% else %}
-<tr><td><div class="comment full_line_comment">{{l.comment|e}}</div></td></tr>
-{% endif %}
-{% endfor %}
-</table></p>
-""")
+        single_c_tmpl = jinja2.Template('<span class="comment">{{c|e}}</span><br />')  ##
         elements_to_write = []
-        last_i = i = 0
-        for booking in db.bookings:
-            i = booking.start_line
-            elements_to_write += [single_c_tmpl.render(c=c) for c in db.comments[last_i:i] if c != '']
+        last_i = i = 0  ##
+        for nth, booking in enumerate(db.bookings):
             booking_end = last_i = booking.start_line + len(booking.lines)
             booking_lines = []
+            i = booking.start_line  ##
+            elements_to_write += [single_c_tmpl.render(c=c) for c in db.comments[last_i:i] if c != '']  ##
             for booking_line in booking.lines[1:]:
-                i += 1
-                comment = db.comments[i] 
-                if booking_line == '':
-                    booking_lines += [{'acc': None, 'money': None, 'comment': comment}]
-                    continue
-                money = ''
-                if booking_line[1]:
-                    money = f'{booking_line[1]} {booking_line[2]}'
-                account = booking_line[0] 
-                booking_lines += [{'acc': booking_line[0], 'money':money, 'comment':comment}] 
-            elements_to_write += [booking_tmpl.render(
+                 i += 1  ##
+                 comment = db.comments[i]  ##
+                 if booking_line == '':
+                     booking_lines += [{'acc': None, 'money': None, 'comment': comment}]  ##
+                     continue
+                 account = booking_line[0]
+                 money = ''
+                 if booking_line[1] is not None:
+                     money = f'{booking_line[1]} {booking_line[2]}'
+                 booking_lines += [{'acc': booking_line[0], 'money':money, 'comment':comment}]  ##
+            elements_to_write += [self.booking_tmpl.render(
+                nth=nth,
                 start=booking.start_line,
                 end=booking_end,
                 date=booking.date_string,
                 desc=booking.description,
                 head_comment=db.comments[booking.start_line],
                 booking_lines = booking_lines)]
-        return '\n'.join(elements_to_write) 
+        elements_to_write += [single_c_tmpl.render(c=c) for c in db.comments[last_i:] if c != '']  #
+        return '\n'.join(elements_to_write)
 
     def add_free(self, db, start=0, end=0, copy=False):
         tmpl = jinja2.Template("""
-<form method="POST" action="{{action}}">
+<form method="POST" action="{{action|e}}">
 <textarea name="booking" rows=10 cols=80>
 {% for line in lines %}{{ line }}
 {% endfor %}
 </textarea>
-<input type="hidden" name="start" value={{start}} />
-<input type="hidden" name="end" value={{end}} />
-<input type="submit" name="save" value="save!">
-</form>
-""")
+""" + self.add_form_footer)
         lines = db.get_lines(start, end)
         if copy:
             start = end = 0
-        return tmpl.render(start=start, end=end, lines=lines) 
+        return tmpl.render(action='add_free', start=start, end=end, lines=lines)
 
     def add_structured(self, db, start=0, end=0, copy=False, temp_lines=[], add_empty_line=None):
         tmpl = jinja2.Template("""
@@ -555,6 +685,8 @@ input[type=number] { text-align: right; font-family: monospace; }
 <input type="submit" name="check" value="check" />
 <input type="submit" name="revert" value="revert" />
 <input type="submit" name="add_taxes" value="add taxes" />
+<input type="submit" name="add_taxes2" value="add taxes2" />
+<input type="submit" name="add_sink" value="add sink" />
 <br />
 <input name="date" value="{{date|e}}" size=9 />
 <input name="description" value="{{desc|e}}" list="descriptions" />
@@ -563,11 +695,12 @@ input[type=number] { text-align: right; font-family: monospace; }
 <br />
 {% for line in booking_lines %}
 <input name="line_{{line.i}}_account" value="{{line.acc|e}}" size=40 list="accounts" />
-<input type="number" name="line_{{line.i}}_amount" value="{{line.amt}}" size=10 />
+<input type="number" name="line_{{line.i}}_amount" step=0.01 value="{{line.amt}}" size=10 />
 <input name="line_{{line.i}}_currency" value="{{line.curr|e}}" size=3 list="currencies" />
-<textarea name="line_{{line.i}}_comment" rows=1 cols={% if line.comm_cols %}{{line.comm_cols}}{% else %}20{% endif %}>{{line.comment|e}}</textarea>
 <input type="submit" name="line_{{line.i}}_delete" value="[x]" />
+<input type="submit" name="line_{{line.i}}_delete_after" value="[XX]" />
 <input type="submit" name="line_{{line.i}}_add" value="[+]" />
+<textarea name="line_{{line.i}}_comment" rows=1 cols={% if line.comm_cols %}{{line.comm_cols}}{% else %}20{% endif %}>{{line.comment|e}}</textarea>
 <br />
 {% endfor %}
 {% for name, items in datalist_sets.items() %}
@@ -577,20 +710,15 @@ input[type=number] { text-align: right; font-family: monospace; }
 {% endfor %}
 </datalist>
 {% endfor %}
-<input type="hidden" name="start" value={{start}} />
-<input type="hidden" name="end" value={{end}} />
-<input type="submit" name="save" value="save!">
-</form>
-""")
-        import datetime
+""" + self.add_form_footer)
         lines = temp_lines if len(''.join(temp_lines)) > 0 else db.get_lines(start, end)
-        bookings, comments = parse_lines(lines)
+        bookings, comments = parse_lines(lines, validate_bookings=False)
         if len(bookings) > 1:
             raise HandledException('can only edit single Booking')
         if add_empty_line is not None:
             comments = comments[:add_empty_line+1] + [''] + comments[add_empty_line+1:]
             booking = bookings[0]
-            booking.lines = booking.lines[:add_empty_line+1] + [''] + booking.lines[add_empty_line+1:] 
+            booking.lines = booking.lines[:add_empty_line+1] + [''] + booking.lines[add_empty_line+1:]
         action = 'add_structured'
         datalist_sets = {'descriptions': set(), 'accounts': set(), 'currencies': set()}
         for b in db.bookings:
@@ -607,8 +735,8 @@ input[type=number] { text-align: right; font-family: monospace; }
         desc = head_comment = ''
         if len(bookings) == 0:
             for i in range(1, 3):
-                booking_lines += [{'i': i, 'acc': '', 'amt': '', 'curr': '', 'comment': ''}]
-            date=today 
+                booking_lines += [{'i': i, 'acc': '', 'amt': '', 'curr': '€', 'comment': ''}]
+            date=today
         else:
             booking = bookings[0]
             desc = booking.description
@@ -622,25 +750,25 @@ input[type=number] { text-align: right; font-family: monospace; }
                     amount = booking.lines[i][1]
                     currency = booking.lines[i][2]
                 booking_lines += [{
-                        'i': i, 
+                        'i': i,
                         'acc': account,
-                        'amt': amount, 
-                        'curr': currency if currency else '',
+                        'amt': amount,
+                        'curr': currency if currency else '€',
                         'comment': comments[i],
                         'comm_cols': len(comments[i])}]
         content += tmpl.render(
-                action=action, 
+                action=action,
                 date=date,
                 desc=desc,
-                head_comment=head_comment, 
+                head_comment=head_comment,
                 booking_lines=booking_lines,
                 datalist_sets=datalist_sets,
                 start=start,
-                end=end) 
-        return content 
+                end=end)
+        return content
 
 
-if __name__ == "__main__":    
+if __name__ == "__main__":  
     webServer = HTTPServer((hostName, serverPort), MyServer)
     print(f"Server started http://{hostName}:{serverPort}")
     try: