from decimal import Decimal, InvalidOperation

from django.template.loader import render_to_string
from liveview import liveview_handler, send

from app.yearly.models import PlannedExpense


MONTH_LABELS = [
	"January",
	"February",
	"March",
	"April",
	"May",
	"June",
	"July",
	"August",
	"September",
	"October",
	"November",
	"December",
]


def _render_planned_tables(year, editing_id=None):
	months_data = []
	for m in range(1, 13):
		items = PlannedExpense.objects.filter(year=year, month=m)
		total = sum(i.amount for i in items)
		months_data.append(
			{
				"month": m,
				"label": MONTH_LABELS[m - 1],
				"items": items,
				"total": total,
			}
		)
	grand_total = sum(md["total"] for md in months_data)

	# Clone years
	available_years = (
		PlannedExpense.objects.exclude(year=year)
		.values_list("year", flat=True)
		.distinct()
		.order_by("-year")
	)

	return render_to_string(
		"pages/yearly/partials/planned_tables.html",
		{
			"months_data": months_data,
			"year": year,
			"grand_total": grand_total,
			"editing_id": editing_id,
			"clone_years": list(available_years),
		},
	)


@liveview_handler("add_planned_expense")
def add_planned_expense(consumer, content):
	form = content.get("form", {})
	year = int(form.get("year", 0))
	month = int(form.get("pe_month", 0))
	concept = form.get("pe_concept", "").strip()
	amount_raw = form.get("pe_amount", "").replace(",", ".")

	if not concept or not amount_raw or not year or not month:
		return

	try:
		amount = Decimal(amount_raw)
	except (InvalidOperation, ValueError):
		return

	PlannedExpense.objects.create(
		year=year, month=month, concept=concept, amount=amount
	)

	html = _render_planned_tables(year)
	send(consumer, {"target": "#planned-expenses", "html": html})


@liveview_handler("edit_planned_expense")
def edit_planned_expense(consumer, content):
	data = content.get("data", {})
	pe_id = data.get("data_id", "")
	year = int(data.get("data_year", 0))

	if not pe_id or not year:
		return

	html = _render_planned_tables(year, editing_id=int(pe_id))
	send(consumer, {"target": "#planned-expenses", "html": html})


@liveview_handler("save_planned_expense")
def save_planned_expense(consumer, content):
	form = content.get("form", {})
	pe_id = form.get("pe_id", "")
	year = int(form.get("year", 0))
	month = int(form.get("pe_month", 0))
	concept = form.get("pe_concept", "").strip()
	amount_raw = form.get("pe_amount", "").replace(",", ".")

	if not pe_id or not concept or not amount_raw or not year or not month:
		return

	try:
		amount = Decimal(amount_raw)
		pe = PlannedExpense.objects.get(id=pe_id)
		pe.month = month
		pe.concept = concept
		pe.amount = amount
		pe.save()
	except (InvalidOperation, ValueError, PlannedExpense.DoesNotExist):
		return

	html = _render_planned_tables(year)
	send(consumer, {"target": "#planned-expenses", "html": html})


@liveview_handler("cancel_edit_planned_expense")
def cancel_edit_planned_expense(consumer, content):
	data = content.get("data", {})
	year = int(data.get("data_year", 0))

	if not year:
		return

	html = _render_planned_tables(year)
	send(consumer, {"target": "#planned-expenses", "html": html})


@liveview_handler("delete_planned_expense")
def delete_planned_expense(consumer, content):
	data = content.get("data", {})
	pe_id = data.get("data_id", "")
	year = int(data.get("data_year", 0))

	if not pe_id or not year:
		return

	PlannedExpense.objects.filter(id=pe_id).delete()

	html = _render_planned_tables(year)
	send(consumer, {"target": "#planned-expenses", "html": html})


@liveview_handler("clone_planned_expenses")
def clone_planned_expenses(consumer, content):
	form = content.get("form", {})
	source_year = int(form.get("clone_pe_source", 0))
	year = int(form.get("year", 0))

	if not source_year or not year:
		return

	source_items = PlannedExpense.objects.filter(year=source_year)
	for item in source_items:
		PlannedExpense.objects.create(
			year=year, month=item.month, concept=item.concept, amount=item.amount
		)

	html = _render_planned_tables(year)
	send(consumer, {"target": "#planned-expenses", "html": html})