#   DrCr: Web-based double-entry bookkeeping framework
#   Copyright (C) 2022  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 abort, redirect, render_template, request

from .. import AMOUNT_DPS
from ..database import db_session
from ..webapp import app
from .models import StatementLine, StatementLinePosting, StatementLineTransaction

@app.route('/statement-lines')
def statement_lines():
	if 'account' in request.args:
		statement_lines = StatementLine.query.filter_by(source_account=request.args['account']).all()
	else:
		statement_lines = StatementLine.query.all()
	
	return render_template('statements/statement_lines.html', statement_lines=sorted(statement_lines, key=lambda l: l.dt))

@app.route('/statement-lines/charge', methods=['POST'])
def statement_line_charge():
	statement_line = db_session.get(StatementLine, request.form['line-id'])
	if not statement_line:
		abort(404)
	
	# Delete existing postings
	statement_line.delete_postings()
	
	transaction = StatementLineTransaction(
		dt=statement_line.dt,
		description=statement_line.description,
		postings=[
			StatementLinePosting(statement_line=statement_line, account=statement_line.source_account, quantity=statement_line.quantity, commodity=statement_line.commodity),
			StatementLinePosting(account=request.form['charge-account'], quantity=-statement_line.quantity, commodity=statement_line.commodity)
		]
	)
	
	db_session.add(transaction)
	db_session.commit()
	
	return 'OK'

@app.route('/statement-lines/edit-transaction', methods=['GET', 'POST'])
def statement_line_edit_transaction():
	statement_line = db_session.get(StatementLine, request.args['line-id'])
	if not statement_line:
		abort(404)
	
	if request.method == 'GET':
		if len(statement_line.postings) == 0:
			return render_template('statements/statement_line_edit_transaction.html', statement_line=statement_line, transaction=None)
		
		if len(statement_line.postings) > 1:
			# NYI
			raise Exception('Cannot display a StatementLine with >2 postings')
		
		# Get existing transaction
		return render_template('statements/statement_line_edit_transaction.html', statement_line=statement_line, transaction=statement_line.postings[0].transaction)
	
	# Delete existing postings
	statement_line.delete_postings()
	
	if len(request.form.getlist('charge-account')) == 1:
		# Simple transaction
		postings = [
			StatementLinePosting(statement_line=statement_line, account=statement_line.source_account, quantity=statement_line.quantity, commodity=statement_line.commodity),
			StatementLinePosting(account=request.form['charge-account'], quantity=-statement_line.quantity, commodity=statement_line.commodity)
		]
	else:
		# Complex transaction, multiple postings
		postings = [
			StatementLinePosting(statement_line=statement_line, account=statement_line.source_account, quantity=statement_line.quantity, commodity=statement_line.commodity)
		]
		
		for charge_account, charge_amount_str in zip(request.form.getlist('charge-account'), request.form.getlist('charge-amount')):
			charge_quantity = round(float(charge_amount_str) * (10**AMOUNT_DPS))
			if statement_line.quantity >= 0:
				# If source is debit, charge is credit
				charge_quantity = -charge_quantity
			postings.append(StatementLinePosting(account=charge_account, quantity=charge_quantity, commodity=statement_line.commodity))
	
	transaction = StatementLineTransaction(
		dt=statement_line.dt,
		description=request.form['description'],
		postings=postings
	)
	transaction.assert_valid()
	
	db_session.add(transaction)
	db_session.commit()
	
	return redirect('/statement-lines')

@app.route('/statement-lines/reconcile-transfer', methods=['POST'])
def statement_line_reconcile_transfer():
	line_ids = request.form.getlist('sel-line-id')
	if len(line_ids) != 2:
		raise Exception('Must select exactly 2 statement lines')
	
	line1 = db_session.get(StatementLine, line_ids[0])
	line2 = db_session.get(StatementLine, line_ids[1])
	
	# Check same amount
	if line1.quantity != -line2.quantity or line1.commodity != line2.commodity:
		raise Exception('Selected statement line debits/credits must equal')
	
	# Delete existing postings
	line1.delete_postings()
	line2.delete_postings()
	
	transaction = StatementLineTransaction(
		dt=line1.dt,
		description=line1.description,
		postings=[
			StatementLinePosting(statement_line=line1, description=line1.description, account=line1.source_account, quantity=line1.quantity, commodity=line1.commodity),
			StatementLinePosting(statement_line=line2, description=line2.description, account=line2.source_account, quantity=line2.quantity, commodity=line2.commodity)
		]
	)
	db_session.add(transaction)
	db_session.commit()
	
	return redirect('/statement-lines')