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Improve ledger.py code.
[misc] / ledger.py
1 from http.server import BaseHTTPRequestHandler, HTTPServer
2 import sys
3 import os
4 import html
5 from urllib.parse import parse_qs, urlparse
6 hostName = "localhost"
7 serverPort = 8082
8
9
10 class HandledException(Exception):
11     pass
12
13
14 def handled_error_exit(msg):
15     print(f"ERROR: {msg}")
16     sys.exit(1)
17
18
19 def apply_booking_to_account_balances(account_sums, account, currency, amount):
20     if not account in account_sums:
21         account_sums[account] = {currency: amount}
22     elif not currency in account_sums[account].keys():
23         account_sums[account][currency] = amount
24     else:
25         account_sums[account][currency] += amount
26
27
28 def parse_lines(lines):
29     import datetime
30     import decimal
31     inside_booking = False
32     date_string, description = None, None
33     booking_lines = []
34     start_line = 0
35     bookings = []
36     comments = []
37     lines += [''] # to ensure a booking-ending last line
38     for i, line in enumerate(lines):
39         prefix = f"line {i}"
40         # we start with the case of an utterly empty line
41         comments += [""]
42         stripped_line = line.rstrip()
43         if stripped_line == '':
44             if inside_booking:
45                 # assume we finished a booking, finalize, and commit to DB
46                 if len(booking_lines) < 2:
47                     raise HandledException(f"{prefix} booking ends to early")
48                 booking = Booking(date_string, description, booking_lines, start_line)
49                 bookings += [booking]
50             # expect new booking to follow so re-zeroall booking data
51             inside_booking = False
52             date_string, description = None, None
53             booking_lines = []
54             continue
55         # if non-empty line, first get comment if any, and commit to DB
56         split_by_comment = stripped_line.split(sep=";", maxsplit=1)
57         if len(split_by_comment) == 2:
58             comments[i] = split_by_comment[1]
59         # if pre-comment empty: if inside_booking, this must be a comment-only line so we keep it for later ledger-output to capture those comments; otherwise, no more to process for this line
60         non_comment = split_by_comment[0].rstrip()
61         if non_comment.rstrip() == '':
62              if inside_booking:
63                  booking_lines += ['']
64              continue
65         # if we're starting a booking, parse by first-line pattern
66         if not inside_booking:
67             start_line = i
68             toks = non_comment.split(maxsplit=1)
69             date_string = toks[0]
70             try:
71                 datetime.datetime.strptime(date_string, '%Y-%m-%d')
72             except ValueError:
73                 raise HandledException(f"{prefix} bad date string: {date_string}")
74             try:
75                 description = toks[1]
76             except IndexError:
77                 raise HandledException(f"{prefix} bad description: {description}")
78             inside_booking = True
79             booking_lines += [non_comment]
80             continue
81         # otherwise, read as transfer data
82         toks = non_comment.split()  # ignore specification's allowance of single spaces in names
83         if len(toks) > 3:
84             raise HandledException(f"{prefix} too many booking line tokens: {toks}")
85         amount, currency = None, None
86         account_name = toks[0]
87         if account_name[0] == '[' and account_name[-1] == ']':
88             # ignore specification's differentiation of "virtual" accounts
89             account_name = account_name[1:-1]
90         decimal_chars = ".-0123456789"
91         if len(toks) == 3:
92             i_currency = 1
93             try:
94                 amount = decimal.Decimal(toks[1])
95                 i_currency = 2
96             except decimal.InvalidOperation:
97                 try:
98                     amount = decimal.Decimal(toks[2])
99                 except decimal.InvalidOperation:
100                     raise HandledException(f"{prefix} no decimal number in: {toks[1:]}")
101             currency = toks[i_currency]
102             if currency[0] in decimal_chars:
103                 raise HandledException(f"{prefix} currency starts with int, dot, or minus: {currency}")
104         elif len(toks) == 2:
105             value = toks[1]
106             inside_amount = False
107             inside_currency = False
108             amount_string = ""
109             currency = ""
110             dots_counted = 0
111             for i, c in enumerate(value):
112                 if i == 0:
113                     if c in decimal_chars:
114                         inside_amount = True
115                     else:
116                         inside_currency = True
117                 if inside_currency:
118                     if c in decimal_chars and len(amount_string) == 0:
119                         inside_currency = False
120                         inside_amount = True
121                     else:
122                         currency += c
123                         continue
124                 if inside_amount:
125                     if c not in decimal_chars:
126                         if len(currency) > 0:
127                             raise HandledException(f"{prefix} amount has non-decimal chars: {value}")
128                         inside_currency = True
129                         inside_amount = False
130                         currency += c
131                         continue
132                     if c == '-' and len(amount_string) > 1:
133                         raise HandledException(f"{prefix} amount has non-start '-': {value}")
134                     if c == '.':
135                         if dots_counted > 1:
136                             raise HandledException(f"{prefix} amount has multiple dots: {value}")
137                         dots_counted += 1
138                     amount_string += c
139             if len(amount_string) == 0:
140                 raise HandledException(f"{prefix} amount missing: {value}")
141             if len(currency) == 0:
142                 raise HandledException(f"{prefix} currency missing: {value}")
143             amount = decimal.Decimal(amount_string)
144         booking_lines += [(account_name, amount, currency)]
145     if inside_booking:
146         raise HandledException(f"{prefix} last booking unfinished")
147     return bookings, comments
148
149 class Booking:
150
151     def __init__(self, date_string, description, booking_lines, start_line):
152         self.date_string = date_string
153         self.description = description
154         self.lines = booking_lines
155         self.start_line = start_line
156         self.validate_booking_lines()
157         self.account_changes = self.parse_booking_lines_to_account_changes()
158
159     def validate_booking_lines(self):
160         prefix = f"booking at line {self.start_line}"
161         sums = {}
162         empty_values = 0
163         for line in self.lines[1:]:
164             if line == '':
165                 continue
166             _, amount, currency = line
167             if amount is None:
168                 if empty_values > 0:
169                     raise HandledException(f"{prefix} relates more than one empty value of same currency {currency}")
170                 empty_values += 1
171                 continue
172             if currency not in sums:
173                 sums[currency] = 0
174             sums[currency] += amount
175         if empty_values == 0:
176             for k, v in sums.items():
177                 if v != 0:
178                     raise HandledException(f"{prefix} does not sum up to zero")
179         else:
180             sinkable = False
181             for k, v in sums.items():
182                 if v != 0:
183                     sinkable = True
184             if not sinkable:
185                 raise HandledException(f"{prefix} has empty value that cannot be filled")
186
187     def parse_booking_lines_to_account_changes(self):
188         account_changes = {}
189         debt = {}
190         sink_account = None
191         for line in self.lines[1:]:
192             if line == '':
193                 continue
194             account, amount, currency = line
195             if amount is None:
196                 sink_account = account
197                 continue
198             apply_booking_to_account_balances(account_changes, account, currency, amount)
199             if currency not in debt:
200                 debt[currency] = amount
201             else:
202                 debt[currency] += amount
203         if sink_account:
204             for currency, amount in debt.items():
205                 apply_booking_to_account_balances(account_changes, sink_account, currency, -amount)
206         return account_changes
207
208
209
210 class Database:
211
212     def __init__(self):
213         db_name = "_ledger"
214         self.db_file = db_name + ".json"
215         self.lock_file = db_name+ ".lock"
216         self.bookings = []
217         self.comments = []
218         self.real_lines = []
219         if os.path.exists(self.db_file):
220             with open(self.db_file, "r") as f:
221                 self.real_lines += f.readlines()
222         ret = parse_lines(self.real_lines)
223         self.bookings += ret[0]
224         self.comments += ret[1]
225
226     def get_lines(self, start, end):
227         return db.real_lines[start:end]
228
229     def replace(self, start, end, lines):
230         import shutil
231         if os.path.exists(self.lock_file):
232             raise HandledException('Sorry, lock file!')
233         if os.path.exists(self.db_file):
234             shutil.copy(self.db_file, self.db_file + ".bak")
235         f = open(self.lock_file, 'w+')
236         f.close()
237         text = ''.join(self.real_lines[:start]) + '\n'.join(lines) + ''.join(self.real_lines[end:])
238         with open(self.db_file, 'w') as f:
239             f.write(text);
240         os.remove(self.lock_file)
241
242     def append(self, lines):
243         import shutil
244         if os.path.exists(self.lock_file):
245             raise HandledException('Sorry, lock file!')
246         if os.path.exists(self.db_file):
247             shutil.copy(self.db_file, self.db_file + ".bak")
248         f = open(self.lock_file, 'w+')
249         f.close()
250         with open(self.db_file, 'a') as f:
251             f.write('\n' + '\n'.join(lines) + '\n');
252         os.remove(self.lock_file)
253
254
255 class MyServer(BaseHTTPRequestHandler):
256     header = """<html>
257 <meta charset="UTF-8">
258 <body>
259 <a href="/ledger">ledger</a>
260 <a href="/balance">balance</a>
261 <a href="/add_free">add free</a>
262 <a href="/add_structured">add structured</a>
263 <hr />
264 """
265     footer = "</body>\n<html>"
266
267     def do_POST(self):
268         length = int(self.headers['content-length'])
269         postvars = parse_qs(self.rfile.read(length).decode(), keep_blank_values=1)
270         parsed_url = urlparse(self.path)
271         if '/add_structured' == parsed_url.path:
272             n_lines = int(len(postvars) / 4) 
273             date = postvars['date'][0] 
274             description = postvars['description'][0]
275             start_comment = postvars['line_0_comment'][0]
276             lines = [f'{date} {description} ; {start_comment}']
277             for i in range(1, n_lines):
278                 account = postvars[f'line_{i}_account'][0]
279                 amount = postvars[f'line_{i}_amount'][0]
280                 currency = postvars[f'line_{i}_currency'][0]
281                 comment = postvars[f'line_{i}_comment'][0]
282                 new_main = f'{account} {amount} {currency}'
283                 if '' == new_main.rstrip() == comment.rstrip():  # don't write empty lines
284                     continue
285                 lines += [f'{new_main} ; {comment}'] 
286         elif '/add_free' == parsed_url.path:
287             lines = postvars['booking'][0].splitlines()
288         start = int(postvars['start'][0])
289         end = int(postvars['end'][0])
290         try:
291             _, _ = parse_lines(lines)
292             if start == end == 0:
293                 db.append(lines)
294             else:
295                 db.replace(start, end, lines)
296             self.send_response(301)
297             self.send_header('Location', '/')
298             self.end_headers()
299         except HandledException as e:
300             self.send_response(400)
301             self.end_headers()
302             page = f'{self.header}ERROR: {e}{self.footer}'
303             self.wfile.write(bytes(page, "utf-8"))
304
305     def do_GET(self):
306         self.send_response(200)
307         self.send_header("Content-type", "text/html")
308         self.end_headers()
309         db = Database()
310         parsed_url = urlparse(self.path)
311         page = self.header + ''
312         params = parse_qs(parsed_url.query)
313         start = int(params.get('start', ['0'])[0])
314         end = int(params.get('end', ['0'])[0])
315         if parsed_url.path == '/balance':
316             page += self.balance_as_html(db)
317         elif parsed_url.path == '/add_free':
318             page += self.add_free(db, start, end)
319         elif parsed_url.path == '/add_structured':
320             bonus_lines = int(params.get('bonus_lines', ['0'])[0])
321             page += self.add_structured(db, start, end)
322         else:
323             page += self.ledger_as_html(db)
324         page += self.footer
325         self.wfile.write(bytes(page, "utf-8"))
326
327     def balance_as_html(self, db):
328         account_sums = {}
329         for booking in db.bookings:
330             for account, changes in booking.account_changes.items():
331                 for currency, amount in changes.items():
332                     apply_booking_to_account_balances(account_sums, account, currency, amount)
333         account_tree = {}
334         def collect_branches(account_name, path):
335             node = account_tree
336             path_copy = path[:]
337             while len(path_copy) > 0:
338                 step = path_copy.pop(0)
339                 node = node[step]
340             toks = account_name.split(":", maxsplit=1)
341             parent = toks[0]
342             if parent in node.keys():
343                 child = node[parent]
344             else:
345                 child = {}
346                 node[parent] = child
347             if len(toks) == 2:
348                 k, v = collect_branches(toks[1], path + [parent])
349                 if k not in child.keys():
350                     child[k] = v
351                 else:
352                     child[k].update(v)
353             return parent, child
354         for account_name in sorted(account_sums.keys()):
355             k, v = collect_branches(account_name, [])
356             if k not in account_tree.keys():
357                 account_tree[k] = v
358             else:
359                 account_tree[k].update(v)
360         def collect_totals(parent_path, tree_node):
361             for k, v in tree_node.items():
362                 child_path = parent_path + ":" + k
363                 for currency, amount in collect_totals(child_path, v).items():
364                     apply_booking_to_account_balances(account_sums, parent_path, currency, amount)
365             return account_sums[parent_path]
366         for account_name in account_tree.keys():
367             account_sums[account_name] = collect_totals(account_name, account_tree[account_name])
368         lines = []
369         def print_subtree(lines, indent, node, subtree, path):
370             line = f"{indent}{node}"
371             n_tabs = 5 - (len(line) // 8)
372             line += n_tabs * "\t"
373             if "€" in account_sums[path + node].keys():
374                 amount = account_sums[path + node]["€"]
375                 line += f"{amount:9.2f} €\t"
376             else:
377                 line += f"\t\t"
378             for currency, amount in account_sums[path + node].items():
379                 if currency != '€' and amount > 0:
380                     line += f"{amount:5.2f} {currency}\t"
381             lines += [line]
382             indent += "  "
383             for k, v in sorted(subtree.items()):
384                 print_subtree(lines, indent, k, v, path + node + ":")
385         for k, v in sorted(account_tree.items()):
386             print_subtree(lines, "", k, v, "")
387         content = "\n".join(lines)
388         return f"<pre>{content}</pre>"
389
390     def ledger_as_html(self, db):
391         lines = []
392         line_sep = '<br />'
393         for comment in db.comments:
394             line = f'; {comment}' if comment != '' else ''
395             lines += [line + line_sep]
396         for booking in db.bookings:
397             i = booking.start_line
398             suffix = lines[i]
399             lines[i] = f'<p>{booking.date_string} {booking.description}{suffix}'
400             for booking_line in booking.lines[1:]:
401                 i += 1
402                 if booking_line == '':
403                     continue
404                 suffix = f' {lines[i]}' if len(lines[i]) > 0 else ''
405                 value = f' {booking_line[1]} {booking_line[2]}' if booking_line[1] else ''
406                 lines[i] = f'{booking_line[0]}{value}{suffix}'
407             lines[i] = lines[i][:-len(line_sep)] + f"""</p>
408 edit:
409 <a href="/add_structured?start={booking.start_line}&end={i+1}">structured</a>
410 / <a href="/add_free?start={booking.start_line}&end={i+1}">free</a>
411 <br />"""
412         return '\n'.join(lines)
413
414     def header_add_form(self, action):
415         return f"<form method=\"POST\" action=\"/{action}\">\n"
416
417     def footer_add_form(self, start, end):
418         return f"""
419 <input type="hidden" name="start" value={start} />
420 <input type="hidden" name="end" value={end} />
421 <input type="submit">
422 </form>"""
423
424     def add_free(self, db, start=0, end=0):
425         content = html.escape(''.join(db.get_lines(start, end)))
426         return f'{self.header_add_form("add_free")}<textarea name="booking" rows="8" cols="80">{content}</textarea>{self.footer_add_form(start, end)}'
427
428     def add_structured(self, db, start=0, end=0, bonus_lines=10):
429         lines = db.get_lines(start, end) 
430         bookings, comments = parse_lines(lines) 
431         if len(bookings) > 1:
432             raise HandledException('can only edit single Booking')
433         input_lines = ''
434         last_line = 0
435         def inpu(name, val=""):
436             safe_val = html.escape(str(val))
437             return f'<input name="{name}" value="{safe_val}" />'
438         if len(bookings) == 0:
439             input_lines += f'{inpu("date")} {inpu("description")} ; {inpu("comment")}<br />' 
440             last_line = 1 
441         else:
442             booking = bookings[0]
443             last_line = len(comments) 
444             input_lines += f'{inpu("date", booking.date_string)} {inpu("description", booking.description)} ; {inpu("comment", comments[0])}<br />' 
445             for i in range(1, len(comments)):
446                 account = amount = currency = ''
447                 if i < len(booking.lines) and booking.lines[i] != '':
448                     account = booking.lines[i][0]
449                     amount = booking.lines[i][1]
450                     currency = booking.lines[i][2]
451                 input_lines += f'{inpu("line_{i}_account", account)} {inpu("line_{i}_amount", amount)} {inpu("line_{i}_currency", currency)} ; {inpu("line_{i}_comment", comments[i])}<br />' 
452         for j in range(bonus_lines):
453             i = j + last_line 
454             input_lines += f'{inpu("line_{i}_account")} {inpu("line_{i}_amount")} {inpu("line_{i}_currency")} ; {inpu("line_{i}_comment")}<br />'
455         return f'{self.header_add_form("add_structured")}{input_lines}{self.footer_add_form(start, end)}'
456
457
458 db = Database()
459 if __name__ == "__main__":     
460     webServer = HTTPServer((hostName, serverPort), MyServer)
461     print(f"Server started http://{hostName}:{serverPort}")
462     try:
463         webServer.serve_forever()
464     except KeyboardInterrupt:
465         pass
466     webServer.server_close()
467     print("Server stopped.")