# Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and Contributors
# License: GNU General Public License v3. See license.txt


import frappe
from frappe import _
from frappe.query_builder.functions import Sum
from frappe.utils import add_days, cstr, flt, formatdate, getdate

import erpnext
from erpnext.accounts.doctype.accounting_dimension.accounting_dimension import (
	get_accounting_dimensions,
	get_dimension_with_children,
)
from erpnext.accounts.report.financial_statements import (
	filter_accounts,
	filter_out_zero_value_rows,
	set_gl_entries_by_account,
)

value_fields = (
	"opening_debit",
	"opening_credit",
	"debit",
	"credit",
	"closing_debit",
	"closing_credit",
)


def execute(filters=None):
	validate_filters(filters)
	data = get_data(filters)
	columns = get_columns()
	return columns, data


def validate_filters(filters):
	if not filters.fiscal_year:
		frappe.throw(_("Fiscal Year {0} is required").format(filters.fiscal_year))

	fiscal_year = frappe.get_cached_value(
		"Fiscal Year", filters.fiscal_year, ["year_start_date", "year_end_date"], as_dict=True
	)
	if not fiscal_year:
		frappe.throw(_("Fiscal Year {0} does not exist").format(filters.fiscal_year))
	else:
		filters.year_start_date = getdate(fiscal_year.year_start_date)
		filters.year_end_date = getdate(fiscal_year.year_end_date)

	if not filters.from_date:
		filters.from_date = filters.year_start_date

	if not filters.to_date:
		filters.to_date = filters.year_end_date

	filters.from_date = getdate(filters.from_date)
	filters.to_date = getdate(filters.to_date)

	if filters.from_date > filters.to_date:
		frappe.throw(_("From Date cannot be greater than To Date"))

	if (filters.from_date < filters.year_start_date) or (filters.from_date > filters.year_end_date):
		frappe.msgprint(
			_("From Date should be within the Fiscal Year. Assuming From Date = {0}").format(
				formatdate(filters.year_start_date)
			)
		)

		filters.from_date = filters.year_start_date

	if (filters.to_date < filters.year_start_date) or (filters.to_date > filters.year_end_date):
		frappe.msgprint(
			_("To Date should be within the Fiscal Year. Assuming To Date = {0}").format(
				formatdate(filters.year_end_date)
			)
		)
		filters.to_date = filters.year_end_date


def get_data(filters):
	accounts = frappe.db.sql(
		"""select name, account_number, parent_account, account_name, root_type, report_type, lft, rgt

		from `tabAccount` where company=%s order by lft""",
		filters.company,
		as_dict=True,
	)
	company_currency = filters.presentation_currency or erpnext.get_company_currency(filters.company)

	if not accounts:
		return None

	accounts, accounts_by_name, parent_children_map = filter_accounts(accounts)

	min_lft, max_rgt = frappe.db.sql(
		"""select min(lft), max(rgt) from `tabAccount`
		where company=%s""",
		(filters.company,),
	)[0]

	gl_entries_by_account = {}

	opening_balances = get_opening_balances(filters)

	# add filter inside list so that the query in financial_statements.py doesn't break
	if filters.project:
		filters.project = [filters.project]

	set_gl_entries_by_account(
		filters.company,
		filters.from_date,
		filters.to_date,
		min_lft,
		max_rgt,
		filters,
		gl_entries_by_account,
		ignore_closing_entries=not flt(filters.with_period_closing_entry),
	)

	calculate_values(accounts, gl_entries_by_account, opening_balances)
	accumulate_values_into_parents(accounts, accounts_by_name)

	data = prepare_data(accounts, filters, parent_children_map, company_currency)
	data = filter_out_zero_value_rows(
		data, parent_children_map, show_zero_values=filters.get("show_zero_values")
	)

	return data


def get_opening_balances(filters):
	balance_sheet_opening = get_rootwise_opening_balances(filters, "Balance Sheet")
	pl_opening = get_rootwise_opening_balances(filters, "Profit and Loss")

	balance_sheet_opening.update(pl_opening)
	return balance_sheet_opening


def get_rootwise_opening_balances(filters, report_type):
	gle = []

	last_period_closing_voucher = frappe.db.get_all(
		"Period Closing Voucher",
		filters={"docstatus": 1, "company": filters.company, "posting_date": ("<", filters.from_date)},
		fields=["posting_date", "name"],
		order_by="posting_date desc",
		limit=1,
	)

	accounting_dimensions = get_accounting_dimensions(as_list=False)

	if last_period_closing_voucher:
		gle = get_opening_balance(
			"Account Closing Balance",
			filters,
			report_type,
			accounting_dimensions,
			period_closing_voucher=last_period_closing_voucher[0].name,
		)
		if getdate(last_period_closing_voucher[0].posting_date) < getdate(
			add_days(filters.from_date, -1)
		):
			start_date = add_days(last_period_closing_voucher[0].posting_date, 1)
			gle += get_opening_balance(
				"GL Entry", filters, report_type, accounting_dimensions, start_date=start_date
			)
	else:
		gle = get_opening_balance("GL Entry", filters, report_type, accounting_dimensions)

	opening = frappe._dict()
	for d in gle:
		opening.setdefault(
			d.account,
			{
				"account": d.account,
				"opening_debit": 0.0,
				"opening_credit": 0.0,
			},
		)
		opening[d.account]["opening_debit"] += flt(d.opening_debit)
		opening[d.account]["opening_credit"] += flt(d.opening_credit)

	return opening


def get_opening_balance(
	doctype, filters, report_type, accounting_dimensions, period_closing_voucher=None, start_date=None
):
	closing_balance = frappe.qb.DocType(doctype)
	account = frappe.qb.DocType("Account")

	opening_balance = (
		frappe.qb.from_(closing_balance)
		.select(
			closing_balance.account,
			Sum(closing_balance.debit).as_("opening_debit"),
			Sum(closing_balance.credit).as_("opening_credit"),
		)
		.where(
			(closing_balance.company == filters.company)
			& (
				closing_balance.account.isin(
					frappe.qb.from_(account).select("name").where(account.report_type == report_type)
				)
			)
		)
		.groupby(closing_balance.account)
	)

	if period_closing_voucher:
		opening_balance = opening_balance.where(
			closing_balance.period_closing_voucher == period_closing_voucher
		)
	else:
		if start_date:
			opening_balance = opening_balance.where(closing_balance.posting_date >= start_date)
			opening_balance = opening_balance.where(closing_balance.is_opening == "No")
		opening_balance = opening_balance.where(closing_balance.posting_date < filters.from_date)

	if (
		not filters.show_unclosed_fy_pl_balances
		and report_type == "Profit and Loss"
		and doctype == "GL Entry"
	):
		opening_balance = opening_balance.where(closing_balance.posting_date >= filters.year_start_date)

	if not flt(filters.with_period_closing_entry):
		if doctype == "Account Closing Balance":
			opening_balance = opening_balance.where(closing_balance.is_period_closing_voucher_entry == 0)
		else:
			opening_balance = opening_balance.where(
				closing_balance.voucher_type != "Period Closing Voucher"
			)

	if filters.cost_center:
		lft, rgt = frappe.db.get_value("Cost Center", filters.cost_center, ["lft", "rgt"])
		cost_center = frappe.qb.DocType("Cost Center")
		opening_balance = opening_balance.where(
			closing_balance.cost_center.in_(
				frappe.qb.from_(cost_center)
				.select("name")
				.where((cost_center.lft >= lft) & (cost_center.rgt <= rgt))
			)
		)

	if filters.project:
		opening_balance = opening_balance.where(closing_balance.project == filters.project)

	if filters.get("include_default_book_entries"):
		opening_balance = opening_balance.where(
			(closing_balance.finance_book.isin([cstr(filters.finance_book), cstr(filters.company_fb), ""]))
			| (closing_balance.finance_book.isnull())
		)
	else:
		opening_balance = opening_balance.where(
			(closing_balance.finance_book.isin([cstr(filters.finance_book), ""]))
			| (closing_balance.finance_book.isnull())
		)

	if accounting_dimensions:
		for dimension in accounting_dimensions:
			if filters.get(dimension.fieldname):
				if frappe.get_cached_value("DocType", dimension.document_type, "is_tree"):
					filters[dimension.fieldname] = get_dimension_with_children(
						dimension.document_type, filters.get(dimension.fieldname)
					)
					opening_balance = opening_balance.where(
						closing_balance[dimension.fieldname].isin(filters[dimension.fieldname])
					)
				else:
					opening_balance = opening_balance.where(
						closing_balance[dimension.fieldname].isin(filters[dimension.fieldname])
					)

	gle = opening_balance.run(as_dict=1)

	return gle


def calculate_values(accounts, gl_entries_by_account, opening_balances):
	init = {
		"opening_debit": 0.0,
		"opening_credit": 0.0,
		"debit": 0.0,
		"credit": 0.0,
		"closing_debit": 0.0,
		"closing_credit": 0.0,
	}

	for d in accounts:
		d.update(init.copy())

		# add opening
		d["opening_debit"] = opening_balances.get(d.name, {}).get("opening_debit", 0)
		d["opening_credit"] = opening_balances.get(d.name, {}).get("opening_credit", 0)

		for entry in gl_entries_by_account.get(d.name, []):
			if cstr(entry.is_opening) != "Yes":
				d["debit"] += flt(entry.debit)
				d["credit"] += flt(entry.credit)

		d["closing_debit"] = d["opening_debit"] + d["debit"]
		d["closing_credit"] = d["opening_credit"] + d["credit"]

		prepare_opening_closing(d)


def calculate_total_row(accounts, company_currency):
	total_row = {
		"account": "'" + _("Total") + "'",
		"account_name": "'" + _("Total") + "'",
		"warn_if_negative": True,
		"opening_debit": 0.0,
		"opening_credit": 0.0,
		"debit": 0.0,
		"credit": 0.0,
		"closing_debit": 0.0,
		"closing_credit": 0.0,
		"parent_account": None,
		"indent": 0,
		"has_value": True,
		"currency": company_currency,
	}

	for d in accounts:
		if not d.parent_account:
			for field in value_fields:
				total_row[field] += d[field]

	return total_row


def accumulate_values_into_parents(accounts, accounts_by_name):
	for d in reversed(accounts):
		if d.parent_account:
			for key in value_fields:
				accounts_by_name[d.parent_account][key] += d[key]


def prepare_data(accounts, filters, parent_children_map, company_currency):
	data = []

	for d in accounts:
		# Prepare opening closing for group account
		if parent_children_map.get(d.account):
			prepare_opening_closing(d)

		has_value = False
		row = {
			"account": d.name,
			"parent_account": d.parent_account,
			"indent": d.indent,
			"from_date": filters.from_date,
			"to_date": filters.to_date,
			"currency": company_currency,
			"account_name": (
				"{} - {}".format(d.account_number, d.account_name) if d.account_number else d.account_name
			),
		}

		for key in value_fields:
			row[key] = flt(d.get(key, 0.0), 3)

			if abs(row[key]) >= 0.005:
				# ignore zero values
				has_value = True

		row["has_value"] = has_value
		data.append(row)

	total_row = calculate_total_row(accounts, company_currency)
	data.extend([{}, total_row])

	return data


def get_columns():
	return [
		{
			"fieldname": "account",
			"label": _("Account"),
			"fieldtype": "Link",
			"options": "Account",
			"width": 300,
		},
		{
			"fieldname": "currency",
			"label": _("Currency"),
			"fieldtype": "Link",
			"options": "Currency",
			"hidden": 1,
		},
		{
			"fieldname": "opening_debit",
			"label": _("Opening (Dr)"),
			"fieldtype": "Currency",
			"options": "currency",
			"width": 120,
		},
		{
			"fieldname": "opening_credit",
			"label": _("Opening (Cr)"),
			"fieldtype": "Currency",
			"options": "currency",
			"width": 120,
		},
		{
			"fieldname": "debit",
			"label": _("Debit"),
			"fieldtype": "Currency",
			"options": "currency",
			"width": 120,
		},
		{
			"fieldname": "credit",
			"label": _("Credit"),
			"fieldtype": "Currency",
			"options": "currency",
			"width": 120,
		},
		{
			"fieldname": "closing_debit",
			"label": _("Closing (Dr)"),
			"fieldtype": "Currency",
			"options": "currency",
			"width": 120,
		},
		{
			"fieldname": "closing_credit",
			"label": _("Closing (Cr)"),
			"fieldtype": "Currency",
			"options": "currency",
			"width": 120,
		},
	]


def prepare_opening_closing(row):
	dr_or_cr = "debit" if row["root_type"] in ["Asset", "Equity", "Expense"] else "credit"
	reverse_dr_or_cr = "credit" if dr_or_cr == "debit" else "debit"

	for col_type in ["opening", "closing"]:
		valid_col = col_type + "_" + dr_or_cr
		reverse_col = col_type + "_" + reverse_dr_or_cr
		row[valid_col] -= row[reverse_col]
		if row[valid_col] < 0:
			row[reverse_col] = abs(row[valid_col])
			row[valid_col] = 0.0
		else:
			row[reverse_col] = 0.0