"""Tool to help identify unreconciled postings.

Run like this:

  python conservancy_beancount/reconcile/helper.py \
    --beancount-file=$HOME/conservancy/beancount/books/2021.beancount \
    --prev-end-date=2021-05-13 --cur-end-date=2021-12-31 \
    --account="Liabilities:CreditCard:AMEX"

In the spirit of bc-reconcile-helper.plx (the original Perl code)

Not implemented:
 - --report-group-regex
 - git branch selection from bean-query-goofy-daemon.plx

"""
import argparse
import csv
from dateutil.relativedelta import relativedelta
import datetime
import decimal
import io
import tempfile
import textwrap
import typing
from typing import List
import os

from beancount import loader
from beancount.query.query import run_query


def end_of_month(date: datetime.date) -> datetime.date:
    """Given a date, return the last day of the month."""
    # Using 'day' replaces, rather than adds.
    return date + relativedelta(day=31)


def format_record_for_grep(row: typing.List, homedir: str) -> typing.List:
    """Return a line in a grep-style.

    This is so the line can be fed into Emacs grep-mode for quickly jumping to
    the relevant lines in the books.
    """
    file = row[0].replace(homedir, '~')
    return [f'{file}:{row[1]}:'] + row[2:]


def max_column_widths(rows: List) -> List[int]:
    """Return the max width for each column in a table of data."""
    if not rows:
        return []
    else:
        maxes = [0] * len(rows[0])
        for row in rows:
            for i, val in enumerate(row):
                length = len(str(val))
                maxes[i] = max(maxes[i], length)
        return maxes


def tabulate(rows: List, headers: List=None) -> str:
    """Format a table of data as a string.

    Implemented here to avoid adding dependency on "tabulate" package.
    """
    output = io.StringIO()
    if headers:
        rows = [headers] + rows
    widths = max_column_widths(rows)
    for row in rows:
        for i, col in enumerate(row):
            width = widths[i]
            if col is None:
                print(' ' * width, end=' ', file=output)
            elif isinstance(col, str):
                print((str(col)).ljust(width), end=' ', file=output)
            else:
                print((str(col)).rjust(width), end=' ', file=output)
        print('', file=output)
    return output.getvalue().strip()


def reconciliation_report(account, end_date, bank_account_balance, uncleared, prev_end_date, our_account_balance, prev_uncleared):
    *_, account_name = account.rpartition(':')
    # end_date_iso = end_date.isoformat()
    # prev_end_date_iso = prev_end_date.isoformat()
    output = io.StringIO()
    w = csv.writer(output)
    w.writerow([f'title:{end_date}: {account_name}'])
    w.writerow(['BANK RECONCILIATION', 'ENDING', end_date])
    w.writerow([f'  {account}'])
    w.writerow([])
    w.writerow(['DATE', 'CHECK NUM', 'PAYEE', 'AMOUNT'])
    w.writerow([])
    w.writerow([end_date, '', 'BANK ACCOUNT BALANCE', bank_account_balance])
    w.writerow([])
    for trans in uncleared:
        w.writerow(trans)
    w.writerow([])
    w.writerow([end_date, '', 'OUR ACCOUNT BALANCE', our_account_balance])
    if prev_uncleared:
        w.writerow([])
        w.writerow(['Items Still', 'Outstanding On', prev_end_date, 'Appeared By', end_date])
        w.writerow([])
        for trans in prev_uncleared:
            w.writerow(trans)
    return output.getvalue()


def reconciliation_report_path(account, end_date):
    *_, account_name = account.rpartition(':')
    return f'Financial/Controls/Reports-for-Treasurer/{end_date}_{account_name}_bank-reconciliation.csv'


# Parse all the arguments
parser = argparse.ArgumentParser(description='Reconciliation helper')
parser.add_argument('--beancount-file', required=True)
parser.add_argument('--account', help='Full account name, e.g. "Liabilities:CreditCard:AMEX"', required=True)
parser.add_argument('--prev-end-date', type=datetime.date.fromisoformat)
parser.add_argument('--cur-end-date', type=datetime.date.fromisoformat)
parser.add_argument('--month', help='YYYY-MM of ending month. Use with --period.')
parser.add_argument('--period', help='Months in the past to consider. Use with --month.', type=int, choices=[1, 3, 12])
parser.add_argument('--statement-match')
parser.add_argument('--cost-function', default='COST')
parser.add_argument('--grep-output-filename')
# parser.add_argument('--report-group-regex')
args = parser.parse_args()
if args.month or args.period:
    if not (args.month and args.period):
        parser.error('--month and --period must be used together')
    parsed_date = datetime.datetime.strptime(args.month, '%Y-%m').date()
    preDate = end_of_month(parsed_date - relativedelta(months=args.period)).isoformat()
    lastDateInPeriod = end_of_month(parsed_date).isoformat()
    month = args.month
else:
    if not (args.cur_end_date and args.prev_end_date):
        parser.error(' --prev-end-date and --cur-end-date must be used together')
    preDate = args.prev_end_date
    lastDateInPeriod = args.cur_end_date.isoformat()
    month = args.cur_end_date.strftime('%Y-%m')
grep_output_file: typing.IO
if args.grep_output_filename:
    grep_output_file = open(args.grep_output_filename, 'w')
else:
    grep_output_file = tempfile.NamedTemporaryFile(prefix='bc-reconcile-grep-output_', mode='w', delete=False)
beancount_file = args.beancount_file
account = args.account
cost_function = args.cost_function
statement_match = args.statement_match if args.statement_match else month

QUERIES = {
    f"00: CLEARED BAL ENDING DAY BEFORE {preDate}":
    # $CONLEDGER -V -C -e "$preDate" bal "/$acct/"
    f"""SELECT sum({cost_function}(position)) AS aa WHERE account = "{account}"
        AND date < {preDate} AND META('bank-statement') != NULL""",

    f"01: ALL TRANSACTION BAL ENDING DAY BEFORE {preDate}":
    # $CONLEDGER -V -e "$preDate" bal "/$acct/"
    f"""SELECT sum({cost_function}(position)) AS aa WHERE account = "{account}"
        AND date < {preDate}""",

    f"02: ALL TRANSACTION BAL, ending {lastDateInPeriod}":
    # $CONLEDGER -V -e "$date" bal "/$acct/"
    f"""SELECT sum({cost_function}(position)) AS aa WHERE account = "{account}"
    AND date <= {lastDateInPeriod}""",

    f"03: UNCLEARED TRANSACTIONS, ending {lastDateInPeriod}":
    f"""SELECT date, {cost_function}(position) as amt, ANY_META('check-id') as chknum, narration, payee, ENTRY_META('code') as code
    WHERE account = "{account}"
    AND date <= {lastDateInPeriod} AND META('bank-statement') = NULL
    ORDER BY date, payee, narration""",

    "04: UNCLEARED TRANSACTION FILE, SUITABLE FOR GREP":
    # $CONLEDGER -w -F "%(filename):%(beg_line): %(date) %(code) %(payee) %(amount)\n" --sort d -U -e "$date" reg "/$acct/" > "$TMPDIR/unreconciled-lines"
    f"""SELECT  ENTRY_META('filename') as file, META('lineno') as line, date,
    {cost_function}(position) as amt, ANY_META('check-id') as chknum, narration, payee, ANY_META("entity") as entity, ENTRY_META('code') as c
    WHERE account = "{account}"
    AND date <= {lastDateInPeriod} AND META('bank-statement') = NULL
    ORDER BY date, payee, narration""",

    f"05: CLEARED BALANCE ending {lastDateInPeriod}":
    # $CONLEDGER -V -C -e "$date" bal "/$acct/"
    f"""SELECT sum({cost_function}(position)) AS aa WHERE account = "{account}"
    AND date <= {lastDateInPeriod} AND META('bank-statement') != NULL""",

    f"06: CLEARED SUBTRACTIONS on {month}'s statement":
    # $CONLEDGER -V -C --limit "a > 0 and tag(\"Statement\") =~ /$statementSearchString/" bal "/$acct/"
    f"""SELECT  sum(number({cost_function}(position))) AS aa
    WHERE account = "{account}"
    and META("bank-statement") ~  "{statement_match}" and number({cost_function}(position)) < 0""",

    f"07: CLEARED ADDITIONS on {month}'s statement":
    # $CONLEDGER -V -C --limit "a < 0 and tag(\"Statement\") =~ /$statementSearchString/" bal "/$acct/"
    f"""SELECT  sum(number({cost_function}(position))) AS aa
    WHERE account = "{account}"
    and META("bank-statement") ~  "{statement_match}" and number({cost_function}(position)) > 0""",
}

# Run Beancount queries.
print(f"START RECONCILIATION FOR {account} ENDING {lastDateInPeriod} (previous end date {preDate})")
entries, _, options = loader.load_file(beancount_file)
uncleared_rows = []  # Hack to capture results of query 03.
cleared_balance = decimal.Decimal('0')
all_trans_balance = decimal.Decimal('0')
for desc, query in QUERIES.items():
    rtypes, rrows = run_query(entries, options, query, numberify=True)
    if not rrows:
        print(f'{desc:<55} {"N/A":>11}')
    elif desc.startswith('04'):
        homedir = os.getenv('HOME', '')
        print(f'{desc}\n   See {grep_output_file.name}')
        grep_rows = [format_record_for_grep(row, homedir) for row in rrows]
        print(tabulate(grep_rows), file=grep_output_file)
    elif len(rrows) == 1 and isinstance(rrows[0][0], decimal.Decimal):
        result = rrows[0][0]
        print(f'{desc:<55} {result:11,.2f}')
        if desc.startswith('02'):
            all_trans_balance = result
        if desc.startswith('05'):
            cleared_balance = result
    else:
        headers = [c[0].capitalize() for c in rtypes]
        if desc.startswith('03'):
            uncleared_rows = rrows
        print(desc)
        print(textwrap.indent(tabulate(rrows, headers=headers), '    '))

uncleared = [(r[0], r[2], r[4] or r[3], r[1]) for r in uncleared_rows]
report_path = os.path.join(os.getenv('CONSERVANCY_REPOSITORY', ''), reconciliation_report_path(account, lastDateInPeriod))
with open(report_path, 'w') as f:
    f.write(reconciliation_report(account, lastDateInPeriod, cleared_balance, uncleared, '1900-01-01', all_trans_balance, []))
print(f'Wrote reconciliation report: {report_path}.')