#   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 Flask, g
import toml
app = Flask(__name__)
app.config.from_file('config.toml', load=toml.load)

from flask_sqlalchemy.record_queries import get_recorded_queries

from .database import db
from .models import Amount, Metadata, Transaction, reporting_commodity
from .plugins import init_plugins, transaction_providers
from .statements.models import StatementLine

from datetime import datetime, timedelta
import time

app.config['SQLALCHEMY_RECORD_QUERIES'] = app.debug
db.init_app(app)

def limit_query_dt(query, field, start_date=None, end_date=None):
	"""Helper function to limit the query between the start and end dates"""
	
	if start_date and end_date:
		return query.where((field >= start_date) & (field <= end_date))
	if start_date:
		return query.where(field >= start_date)
	if end_date:
		return query.where(field <= end_date)
	return query

def all_transactions(start_date=None, end_date=None, join_postings=True):
	"""Return all transactions, including from DB and API"""
	
	# All Transactions in database between start_date and end_date
	query = db.select(Transaction)
	query = limit_query_dt(query, Transaction.dt, start_date, end_date)
	if join_postings:
		query = query.options(db.selectinload(Transaction.postings))
	
	transactions = db.session.scalars(query).all()
	
	transactions.extend(api_transactions(start_date=start_date, end_date=end_date))
	
	return transactions

def api_transactions(start_date=None, end_date=None):
	"""Return only transactions from API"""
	
	transactions = []
	
	# Unreconciled StatementLines
	query = db.select(StatementLine).where(StatementLine.reconciliation == None)
	query = limit_query_dt(query, StatementLine.dt, start_date, end_date)
	transactions.extend(line.into_transaction() for line in db.session.scalars(query).all())
	
	# Plugins
	for transaction_provider in transaction_providers:
		transactions.extend(transaction_provider(start_date=start_date, end_date=end_date))
	
	return transactions

def all_accounts():
	# TODO: Can this be cached?
	return sorted(list(set(p.account for t in all_transactions() for p in t.postings)))

def eofy_date():
	"""Get the datetime for the end of the financial year"""
	
	return datetime.strptime(Metadata.get('eofy_date'), '%Y-%m-%d')

def sofy_date():
	"""Get the datetime for the start of the financial year"""
	
	dt = eofy_date()
	dt = dt.replace(year=dt.year - 1)
	dt += timedelta(days=1)
	return dt

from . import views
from .journal import views
from .statements import views

init_plugins()

@app.cli.command('initdb')
def initdb():
	"""Initialise database tables"""
	
	db.create_all()
	
	# FIXME: Need to init metadata

@app.cli.command('recache_balances')
def recache_balances():
	"""Recompute running_balance for all postings"""
	
	# Get all Transactions in database in correct order
	transactions = db.session.scalars(db.select(Transaction).options(db.selectinload(Transaction.postings)).order_by(Transaction.dt, Transaction.id)).all()
	
	accounts = {}
	
	for transaction in transactions:
		for posting in transaction.postings:
			if posting.account not in accounts:
				accounts[posting.account] = Amount(0, reporting_commodity())
			
			# FIXME: Handle commodities better (ensure compatible commodities)
			accounts[posting.account].quantity += posting.amount().as_cost().quantity
			
			posting.running_balance = accounts[posting.account].quantity
	
	db.session.commit()

@app.context_processor
def add_reporting_commodity():
	return dict(reporting_commodity=reporting_commodity())

if app.debug:
	@app.before_request
	def before_request():
		g.start = time.time()
	
	@app.after_request
	def after_request(response):
		diff = time.time() - g.start
		if response.response and response.status_code == 200 and response.content_type.startswith('text/html'):
			response.set_data(response.get_data().replace(b'__EXECUTION_TIME__', bytes(format(diff * 1000, '.1f'), 'utf-8')))
		return response
	
	@app.context_processor
	def add_dbtime():
		def dbtime():
			queries = get_recorded_queries()
			total_duration = sum(q.duration for q in queries)
			return format(total_duration * 1000, '.1f')
		return dict(dbtime=dbtime)