#!/bin/env python3

import argparse
import csv
import datetime
import decimal
import getpass
import sys

import triad.client

argparser = argparse.ArgumentParser(description='Beitragsrechnungen für ein Jahr erzeugen')
argparser.add_argument('-u', '--username', help='Tryton-Benutzername', default='fgrimpen')
argparser.add_argument('-p', '--password', help='Tryton-Passwort')
argparser.add_argument('-U', '--url', help='Tryton-URL', default='https://kasse.verein.ccchb.de/tryton/')
argparser.add_argument('--reference-date', help='Referenzdatum für Zahlungsbedingung', type=datetime.date.fromisoformat)
argparser.add_argument('--claims-account', help='Forderungskonto', default='12001')
argparser.add_argument('--fee-account', help='Beitragskonto', default='40000')
argparser.add_argument('--default-payment-term', default='1m')
argparser.add_argument('--csv-format', type=lambda x: x.split(",") if isinstance(x, str) else list(x), default='party_id,monthly_fee,payment_term,yearly_fee', help='CSV format specification')
argparser.add_argument('-n', '--dry-run', action='store_true')
argparser.add_argument('year', help='Beitragsjahr', type=lambda s: datetime.date(int(s), 1, 1))
argparser.add_argument('csvfile', nargs='?', type=argparse.FileType('r'), default='-')

args = argparser.parse_args()

if not args.password:
    args.password = getpass.getpass(f"Password for {args.username}@{args.url}: ")

def calculate_reference_date(date):
    today = datetime.date.today()
    if today >= date:
        date = today
    while date.day >= 10:
        date += datetime.timedelta(days=1)
    while date.day != 15:
        date += datetime.timedelta(days=1)
    return date

if not args.reference_date:
    args.reference_date = calculate_reference_date(args.year)

csvreader = csv.DictReader(args.csvfile, fieldnames=args.csv_format)

PAYMENT_TERMS_MAPPING = [
    ({'1m'}, 'Beitrag monatlich/jährlich'),
    ({'3m'}, 'Beitrag quartalsweise/jährlich'),
    ({'6m'}, 'Beitrag halbjährlich/jährlich'),
    ({'1y', '12m'}, 'Beitrag jährlich/jährlich')
]

def load_payment_terms(session, invoicing_client):
    ret = {}
    for keys, payment_term_name in PAYMENT_TERMS_MAPPING:
        payment_term = invoicing_client.PaymentTerm.find([('name', '=', payment_term_name)])[0]
        ret.update({key: payment_term for key in keys})
    return ret


def create_invoice(party, payment_term, monthly_fee, yearly_fee, claims_account, fee_account, invoicing_client, reference_date, year):
    invoice = invoicing_client.Invoice()
    invoice.type = 'out'
    invoice.party = party
    invoice.description = f"Beiträge {year.year}"
    invoice.account = claims_account
    invoice.payment_term = payment_term
    invoice.payment_term_date = reference_date
    if monthly_fee:
        invoice_line = invoicing_client.InvoiceLine()
        invoice_line.description = f"Monatsbeiträge Januar--Dezember {year.year}"
        invoice_line.account = fee_account
        invoice_line.quantity = decimal.Decimal(12) # Months
        invoice_line.unit_price = decimal.Decimal(monthly_fee)
        invoice.lines.append(invoice_line)
    if yearly_fee:
        invoice_line = invoicing_client.InvoiceLine()
        invoice_line.description = f"Jahresbeitrag {year.year}"
        invoice_line.account = fee_account
        invoice_line.quantity = decimal.Decimal(1)
        invoice_line.unit_price = decimal.Decimal(yearly_fee)
        invoice.lines.append(invoice_line)
    invoice.state = 'draft'
    return invoice

with triad.client.Session.start(args.url, args.username, args.password) as session:
    party_client = triad.client.PartyClient.from_session(session)
    invoicing_client = triad.client.InvoicingClient.from_session(session)
    accounting_client = triad.client.AccountingClient.from_session(session)

    claims_account = accounting_client.get_account_by_code(args.claims_account)
    print(f"Claims account: {claims_account.code}  {claims_account.name}", file=sys.stderr)
    fee_account = accounting_client.get_account_by_code(args.fee_account)
    print(f'Fee account: {fee_account.code}  {fee_account.name}', file=sys.stderr)
    payment_terms = load_payment_terms(invoicing_client, invoicing_client)
    for key, payment_term in payment_terms.items():
        print(f"Payment term {key}: {payment_term.name}", file=sys.stderr)
    print(f'Fee year: {args.year}', file=sys.stderr)
    print(f'Reference date: {args.reference_date}', file=sys.stderr)
    for member in csvreader:
        party = party_client.get_party_by_code(member['party_id'])
        print(f"Party: {party.code}  {party.name}", file=sys.stderr)
        try:
            payment_term = payment_terms[member['payment_term']]
        except KeyError:
            payment_term = payment_terms[args.default_payment_term]
        print(f"\tPayment term: {payment_term.name}", file=sys.stderr)
        try:
            monthly_fee = decimal.Decimal(member['monthly_fee'])
        except:
            print(f"\tInvalid monthly fee: {member['monthly_fee']}", file=sys.stderr)
            monthly_fee = None
        else:
            print(f"\tMonthly fee: {monthly_fee}", file=sys.stderr)
        try:
            yearly_fee = decimal.Decimal(member['yearly_fee'])
        except:
            print(f'\tInvalid yearly fee: {member['yearly_fee']}', file=sys.stderr)
            yearly_fee = None
        else:
            print(f'\tYearly fee: {yearly_fee}', file=sys.stderr)
        invoice = create_invoice(party, payment_term, monthly_fee, yearly_fee, claims_account, fee_account, invoicing_client, args.reference_date, args.year)
        if not args.dry_run:
            invoice.save()
        print(f'\tInvoice: {invoice.id}  {invoice.description}', file=sys.stderr)
        for line in invoice.lines:
            print(f'\tLine: {line.description}  {line.quantity} * {line.unit_price}', file=sys.stderr)
        print(f'\tYearly fee: {invoice.total_amount}', file=sys.stderr)
        print(f"{member['party_id']},{invoice.id},{invoice.total_amount},{payment_term.name}")