from __future__ import annotations

from typing import overload, Optional, TYPE_CHECKING

import tcod.event

from actions import Action, BumpAction, EscapeAction, WaitAction

if TYPE_CHECKING:
    from engine import Engine

MOVE_KEYS = {
    # Arrow keys
    tcod.event.K_UP: (0, -1),
    tcod.event.K_DOWN: (0, 1),
    tcod.event.K_LEFT: (-1, 0),
    tcod.event.K_RIGHT: (1, 0),
    tcod.event.K_HOME: (-1, -1),
    tcod.event.K_END: (-1, 1),
    tcod.event.K_PAGEUP: (1, -1),
    tcod.event.K_PAGEDOWN: (1, 1),

    # Numpad keys
    tcod.event.K_KP_1: (-1, 1),
    tcod.event.K_KP_2: (0, 1),
    tcod.event.K_KP_3: (1, 1),
    tcod.event.K_KP_4: (-1, 0),
    tcod.event.K_KP_6: (1, 0),
    tcod.event.K_KP_7: (-1, -1),
    tcod.event.K_KP_8: (0, -1),
    tcod.event.K_KP_9: (1, -1),

    # Vi keys
    tcod.event.K_h: (-1, 0),
    tcod.event.K_j: (0, 1),
    tcod.event.K_k: (0, -1),
    tcod.event.K_l: (1, 0),
    tcod.event.K_y: (-1, -1),
    tcod.event.K_u: (1, -1),
    tcod.event.K_b: (-1, 1),
    tcod.event.K_n: (1, 1),
}

WAIT_KEYS = {
    tcod.event.K_PERIOD,
    tcod.event.K_KP_5,
    tcod.event.K_CLEAR,
}


class EventHandler(tcod.event.EventDispatch[Action]):
    def __init__(self, engine: Engine):
        self.engine = engine

    def handle_events(self, context: tcod.context.Context) -> None:
        for event in tcod.event.wait():
            context.convert_event(event)
            self.dispatch(event)

    def ev_mousemotion(self, event: tcod.event.MouseMotion) -> None:
        if self.engine.game_map.in_bounds(event.tile.x, event.tile.y):
            self.engine.mouse_location = event.tile.x, event.tile.y

    def ev_quit(self, event: tcod.event.Quit) -> Optional[Action]:
        raise SystemExit()

    def on_render(self, console: tcod.Console) -> None:
        self.engine.render(console)


class MainGameEventHandler(EventHandler):
    def handle_events(self, context: tcod.context.Context) -> None:
        for event in tcod.event.wait():
            context.convert_event(event)

            action = self.dispatch(event)

            if action is None:
                continue

            action.perform()

            self.engine.handle_enemy_turns()
            self.engine.update_fov()

    def ev_keydown(self, event: tcod.event.KeyDown) -> Optional[Action]:
        action: Optional[Action] = None

        key = event.sym

        player = self.engine.player

        if key in MOVE_KEYS:
            dx, dy = MOVE_KEYS[key]
            action = BumpAction(player, dx, dy)
        elif key in WAIT_KEYS:
            action = WaitAction(player)

        elif key == tcod.event.K_ESCAPE:
            action = EscapeAction(player)
        elif key == tcod.event.K_v:
            self.engine.event_handler = HistoryViewer(self.engine)

        # No valid key was pressed
        return action


class GameOverEventHandler(EventHandler):
    def handle_events(self, context: tcod.context.Context) -> None:
        for event in tcod.event.wait():
            action = self.dispatch(event)

            if action is None:
                continue

            action.perform()

    def ev_keydown(self, event: tcod.event.KeyDown) -> Optional[Action]:
        action: Optional[Action] = None

        key = event.sym

        if key == tcod.event.K_ESCAPE:
            action = EscapeAction(self.engine.player)

        # No valid key was pressed
        return action


CURSOR_Y_KEYS = {
    tcod.event.K_UP: -1,
    tcod.event.K_DOWN: 1,
    tcod.event.K_PAGEUP: -10,
    tcod.event.K_PAGEDOWN: 10,
}


class HistoryViewer(EventHandler):
    """Print the history on a larger window which can be navigated."""

    def __init__(self, engine: Engine):
        super().__init__(engine)
        self.log_length = len(engine.message_log.messages)
        self.cursor = self.log_length - 1

    def on_render(self, console: tcod.Console) -> None:
        super().on_render(console)  # Draw the main state as the background.

        log_console = tcod.Console(console.width - 6, console.height - 6)

        # Draw a frame with a custom banner title.
        log_console.draw_frame(0, 0, log_console.width, log_console.height)
        log_console.print_box(
            0,
            0,
            log_console.width,
            1,
            "┤Message history├",
            alignment=tcod.CENTER
        )

        # Render the message log using the cursor parameter.
        self.engine.message_log.render_messages(
            log_console,
            1,
            1,
            log_console.width - 2,
            log_console.height - 2,
            self.engine.message_log.messages[: self.cursor + 1],
        )
        log_console.blit(console, 3, 3)

    def ev_keydown(self, event: tcod.event.KeyDown) -> None:
        # Fancy conditional movement to make it feel right.
        if event.sym in CURSOR_Y_KEYS:
            adjust = CURSOR_Y_KEYS[event.sym]
            if adjust < 0 and self.cursor == 0:
                # Only move from the top to the bottom when you're on the edge.
                self.cursor = self.log_length - 1
            elif adjust > 0 and self.cursor == self.log_length - 1:
                # Same with bottom to top movement.
                self.cursor = 0
            else:
                # Otherwise move while staying clamped to the bounds of the history log.
                self.cursor = max(0, min(self.cursor + adjust, self.log_length - 1))
        elif event.sym == tcod.event.K_HOME:
            self.cursor = 0  # Move directly to the top message.
        elif event.sym == tcod.event.K_END:
            self.cursor = self.log_length - 1  # Move directly to the last message.
        else:  # Any other key moves back to the main game state.
            self.engine.event_handler = MainGameEventHandler(self.engine)