"""pgt TUI application loop."""

from __future__ import annotations

from pathlib import Path

from pyratatui import Frame, Terminal

from pygittools.tui.git_colors import init_tui_color_theme, status_bar_style
from pygittools.tui.pages.home import HomePage, home_page
from pygittools.tui.pages.no_repo import NoRepoPage
from pygittools.tui.repo import try_open_page_context
from pygittools.tui.status_bar import render_status_bar, split_content_status
from pygittools.tui.tabs import init_tab_colors
from pygittools.tui.types import Page, PageAction, PageContext, PageResult


def run_tui(repo_path: Path | None = None) -> int:
	start = (repo_path or Path.cwd()).resolve()
	ctx = try_open_page_context(start)
	initial: Page = home_page() if ctx is not None else NoRepoPage(start)
	stack: list[Page] = [initial]

	with Terminal() as term:
		term.hide_cursor()
		try:
			init_tui_color_theme(ctx.repo if ctx is not None else None)
			init_tab_colors()

			if ctx is not None:
				stack[0].on_enter(ctx)

			while stack:
				page = stack[-1]

				def ui(frame: Frame, _page: Page = page) -> None:
					content, status = split_content_status(frame.area)
					_page.draw(frame, content)
					render_status_bar(frame, status, _page.status_text(), status_bar_style())

				term.draw(ui)

				try:
					ev = term.poll_event(timeout_ms=100)
				except KeyboardInterrupt:
					break
				if ev is None:
					on_idle = getattr(page, "on_idle", None)
					if callable(on_idle):
						on_idle()
					continue

				result = page.handle_key(ev)
				ctx, stack = _apply_result(stack, ctx, result)
				if result.action == PageAction.QUIT:
					break
		except KeyboardInterrupt:
			pass
		finally:
			_persist_commit_draft(stack, ctx)

	return 0


def _persist_commit_draft(stack: list[Page], ctx: PageContext | None) -> None:
	if ctx is None:
		return
	for page in reversed(stack):
		if isinstance(page, HomePage):
			page.changes.persist_commit_draft(ctx.repo)
			return


def _apply_result(
	stack: list[Page],
	ctx: PageContext | None,
	result: PageResult,
) -> tuple[PageContext | None, list[Page]]:
	if result.switch_repo is not None:
		_persist_commit_draft(stack, ctx)
		new_ctx = try_open_page_context(result.switch_repo)
		if new_ctx is not None:
			ctx = new_ctx
			init_tui_color_theme(ctx.repo)
			init_tab_colors()

	match result.action:
		case PageAction.REPLACE:
			if result.next_page is None:
				return ctx, stack
			if ctx is not None:
				result.next_page.on_enter(ctx)
			return ctx, [result.next_page]
		case PageAction.PUSH:
			if result.next_page is None:
				return ctx, stack
			if ctx is not None:
				result.next_page.on_enter(ctx)
			return ctx, [*stack, result.next_page]
		case PageAction.POP:
			if len(stack) <= 1:
				return ctx, stack
			stack = stack[:-1]
		case _:
			pass

	if result.switch_repo is not None and ctx is not None and stack:
		stack[-1].on_enter(ctx)

	return ctx, stack