#   DrCr: Web-based double-entry bookkeeping framework
#   Copyright (C) 2022–2024  Lee Yingtong Li (RunasSudo)
#
#   This program is free software: you can redistribute it and/or modify
#   it under the terms of the GNU Affero General Public License as published by
#   the Free Software Foundation, either version 3 of the License, or
#   (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU Affero General Public License for more details.
#
#   You should have received a copy of the GNU Affero General Public License
#   along with this program.  If not, see <https://www.gnu.org/licenses/>.

from flask import redirect, render_template, request, url_for

from .database import db
from .models import AccountConfiguration, Amount, Balance, Posting, TrialBalancer, reporting_commodity
from .plugins import account_kinds, advanced_reports, data_sources
from .reports import balance_sheet_report, income_statement_report
from .webapp import all_transactions, api_transactions, app

from datetime import datetime
from itertools import groupby

@app.route('/')
def index():
	return render_template('index.html', data_sources=data_sources, advanced_reports=advanced_reports)

@app.route('/chart-of-accounts')
def chart_of_accounts():
	#accounts = sorted(db.session.execute(db.select(Posting.account)).unique().scalars().all())
	accounts = sorted(list(set(p.account for t in all_transactions() for p in t.postings)))
	
	# Get existing AccountConfiguration's
	account_configurations = AccountConfiguration.get_all()
	
	# Preprocess account kinds
	account_kinds_by_plugin = {v: list(g) for v, g in groupby(account_kinds, key=lambda k: k[0][:k[0].index('.')])}
	account_kinds_map = {name: label for name, label in account_kinds}
	
	# TODO: Handle orphans
	return render_template(
		'chart_of_accounts.html',
		accounts=accounts,
		account_configurations=account_configurations,
		account_kinds_by_plugin=account_kinds_by_plugin,
		account_kinds_map=account_kinds_map
	)

@app.route('/chart-of-accounts/add-kind', methods=['POST'])
def account_add_kind():
	for account in request.form.getlist('sel-account'):
		account_configuration = AccountConfiguration(account=account, kind=request.form['kind'])
		db.session.add(account_configuration)
	
	db.session.commit()
	
	return redirect(url_for('chart_of_accounts'))

@app.route('/general-ledger')
def general_ledger():
	return render_template(
		'general_ledger.html',
		commodity_detail=request.args.get('commodity_detail', '0') == '1',
		transactions=sorted(all_transactions(), key=lambda t: t.dt, reverse=True)
	)

@app.route('/trial-balance')
def trial_balance():
	dt = datetime.strptime(request.args['date'], '%Y-%m-%d') if 'date' in request.args else None
	
	balancer = TrialBalancer.from_cached(end_date=dt)
	balancer.apply_transactions(api_transactions(end_date=dt))
	
	total_dr = Amount(sum(v.quantity for v in balancer.accounts.values() if v.quantity > 0), reporting_commodity())
	total_cr = Amount(sum(v.quantity for v in balancer.accounts.values() if v.quantity < 0), reporting_commodity())
	
	return render_template('trial_balance.html', accounts=dict(sorted(balancer.accounts.items())), total_dr=total_dr, total_cr=total_cr)

@app.route('/account-transactions')
def account_transactions():
	# FIXME: Filter in SQL
	transactions = [t for t in all_transactions() if any(p.account == request.args['account'] for p in t.postings)]
	
	if request.args.get('commodity_detail', '0') == '1':
		# Pre-compute running totals
		# At the level of individual transactions
		running_totals = {}
		running_total = Balance()
		for transaction in sorted(transactions, key=lambda t: t.dt):
			for posting in transaction.postings:
				if posting.account == request.args['account']:
					running_total.add(posting.amount())
			
			running_totals[transaction] = running_total.clone()
			running_total.clean()
		
		return render_template(
			'transactions_commodity_detail.html',
			account=request.args['account'],
			running_totals=running_totals,
			transactions=reversed(sorted(transactions, key=lambda t: t.dt))
		)
	else:
		# Pre-compute running totals
		# There can be more than one posting per account per transaction, so track the running total at the level of individual postings
		running_totals = {}
		running_total = Amount(0, reporting_commodity())
		for transaction in sorted(transactions, key=lambda t: t.dt):
			for posting in transaction.postings:
				if posting.account == request.args['account']:
					running_total += posting.amount().as_cost()
					running_totals[posting] = running_total
		
		return render_template(
			'transactions.html',
			account=request.args['account'],
			running_totals=running_totals,
			transactions=reversed(sorted(transactions, key=lambda t: t.dt))
		)

@app.route('/balance-sheet')
def balance_sheet():
	report = balance_sheet_report()
	return render_template('report.html', report=report)

@app.route('/income-statement')
def income_statement():
	if 'end_date' in request.args:
		start_date = datetime.strptime(request.args['start_date'], '%Y-%m-%d') if 'start_date' in request.args else datetime.min
		end_date = datetime.strptime(request.args['end_date'], '%Y-%m-%d')
		
		print(end_date)
	else:
		start_date, end_date = None, None
	
	report = income_statement_report(start_date=start_date, end_date=end_date)
	return render_template('report.html', report=report)