"""Window loop and script runner for Dream Chat Engine."""

from __future__ import annotations

import queue
import threading
import time
import tkinter as tk
from collections import OrderedDict
from pathlib import Path
from typing import Any, Sequence

from PIL import Image, ImageTk

from .actions import Ask, Generate, GeneratedReply, Hide, Say, SetBackground, Show
from .assets import AssetManager
from .character import CharacterSprite
from .config import EngineConfig
from .dialogue import DialogueState
from .renderer import SceneRenderer

ScriptAction = SetBackground | Show | Hide | Say | Generate | Ask


class DreamChatEngine:
    def __init__(
        self,
        script: Sequence[ScriptAction],
        project_root: str | Path,
        config: EngineConfig | None = None,
        voice_manager: object | None = None,
    ) -> None:
        self.script = list(script)
        self.config = config or EngineConfig()
        self.assets = AssetManager(project_root)
        self.dialogue = DialogueState(text_speed=self.config.text_speed)
        self.renderer = SceneRenderer(self.config)
        self.voice_manager = voice_manager
        self.background: Image.Image | None = None
        self.characters: OrderedDict[str, CharacterSprite] = OrderedDict()
        self.variables: dict[str, str] = {}
        self.history: list[dict[str, str]] = []

        self._index = 0
        self._active_ask: Ask | None = None
        self._generation_queue: queue.Queue[dict[str, Any]] | None = None
        self._generation_thread: threading.Thread | None = None
        self._speech_handle: Any | None = None
        self._demo_finished = False
        self._last_tick = time.perf_counter()

        self._root: tk.Tk | None = None
        self._canvas: tk.Canvas | None = None
        self._photo: ImageTk.PhotoImage | None = None

    def run(self) -> None:
        self._root = tk.Tk()
        self._root.title(self.config.title)
        self._root.geometry(f"{self.config.width}x{self.config.height}")
        self._root.minsize(self.config.min_width, self.config.min_height)

        self._canvas = tk.Canvas(self._root, highlightthickness=0, bg="black")
        self._canvas.pack(fill=tk.BOTH, expand=True)
        self._canvas.focus_set()

        self._root.bind("<Key>", self._on_key)
        self._root.bind("<Button-1>", self._on_click)
        self._canvas.bind("<Button-1>", self._on_click)

        self._advance_script()
        self._tick()
        self._root.mainloop()

    def _tick(self) -> None:
        now = time.perf_counter()
        delta = now - self._last_tick
        self._last_tick = now
        self.dialogue.update(delta)
        self._drain_generation_queue()
        self._maybe_auto_advance()
        self._render()

        if self._root is not None:
            delay_ms = max(1, int(1000 / self.config.fps))
            self._root.after(delay_ms, self._tick)

    def _render(self) -> None:
        if self._canvas is None:
            return

        width = max(1, self._canvas.winfo_width())
        height = max(1, self._canvas.winfo_height())
        if width <= 1 or height <= 1:
            width, height = self.config.width, self.config.height

        frame = self.renderer.compose(
            (width, height),
            self.background,
            self.characters.values(),
            self.dialogue,
        )
        self._photo = ImageTk.PhotoImage(frame)
        self._canvas.delete("all")
        self._canvas.create_image(0, 0, anchor=tk.NW, image=self._photo)

    def _advance_script(self) -> None:
        self._active_ask = None
        self._speech_handle = None

        while self._index < len(self.script):
            action = self.script[self._index]
            self._index += 1

            if isinstance(action, SetBackground):
                self.background = self.assets.load_background(action.image)
                continue

            if isinstance(action, Show):
                tag = action.tag or action.name
                self.characters[tag] = CharacterSprite(
                    tag=tag,
                    name=action.name,
                    image=self.assets.load_character(action.image),
                    position=action.position,
                )
                continue

            if isinstance(action, Hide):
                self.characters.pop(action.tag, None)
                continue

            if isinstance(action, Say):
                speaker = self._format(action.speaker)
                text = self._format(action.text)
                self.dialogue.start_say(speaker, text)
                self._record_line(speaker, text)
                self._speech_handle = self._speak(speaker, text)
                return

            if isinstance(action, Generate):
                self._start_generated_reply(action)
                return

            if isinstance(action, Ask):
                self._active_ask = action
                self.dialogue.start_input(
                    self._format(action.speaker),
                    self._format(action.prompt),
                )
                return

        if self.config.end_message is not None and not self._demo_finished:
            self._demo_finished = True
            self.dialogue.start_say(self.config.end_speaker, self.config.end_message)
        else:
            self.close()

    def _on_click(self, _event: tk.Event) -> None:
        if self.dialogue.mode == "input":
            return
        self._continue_or_skip()

    def _on_key(self, event: tk.Event) -> None:
        keysym = event.keysym

        if self.dialogue.mode == "input":
            self._handle_input_key(event)
            return

        if keysym in {"space", "Return"}:
            self._continue_or_skip()

    def _continue_or_skip(self) -> None:
        if self.config.auto_advance or self.dialogue.mode == "loading":
            return
        if not self._speech_is_done():
            return
        if self.dialogue.mode != "say":
            return

        if not self.dialogue.is_complete:
            self.dialogue.reveal_all()
            return

        self._advance_script()

    def _handle_input_key(self, event: tk.Event) -> None:
        keysym = event.keysym

        if keysym == "Return":
            self._submit_input()
        elif keysym == "BackSpace":
            self.dialogue.backspace()
        elif keysym == "Delete":
            self.dialogue.delete()
        elif keysym == "Left":
            self.dialogue.move_caret(-1)
        elif keysym == "Right":
            self.dialogue.move_caret(1)
        elif keysym == "Home":
            self.dialogue.move_caret_home()
        elif keysym == "End":
            self.dialogue.move_caret_end()
        elif event.char:
            self._insert_input_text(event.char)

    def _insert_input_text(self, text: str) -> None:
        max_chars = self.config.max_input_chars
        if self._active_ask is not None and self._active_ask.max_chars is not None:
            max_chars = self._active_ask.max_chars

        if self._active_ask is not None and self._active_ask.input_rule == "letters":
            text = "".join(ch for ch in text if ch.isalpha())

        self.dialogue.insert_text(text, max_chars)

    def _submit_input(self) -> None:
        if self._active_ask is None:
            return

        response = self.dialogue.submit_input()
        if len(response) < self._active_ask.min_chars:
            self.dialogue.start_input(
                self._format(self._active_ask.speaker),
                self._format(self._active_ask.prompt),
            )
            return

        if not response:
            response = "..."

        self.variables[self._active_ask.variable] = response
        response_speaker = self._active_ask.response_speaker or self._active_ask.speaker
        speaker = self._format(response_speaker)
        self.dialogue.start_say(speaker, response)
        self._record_line(speaker, response)
        self._speech_handle = self._speak(speaker, response)
        self._active_ask = None

    def _start_generated_reply(self, action: Generate) -> None:
        speaker = self._format(action.speaker)
        self.dialogue.start_loading(speaker)
        self._speech_handle = None
        self._generation_queue = queue.Queue()

        variables = dict(self.variables)
        history = [dict(item) for item in self.history]

        def worker() -> None:
            try:
                reply = action.producer(variables, history)
                if isinstance(reply, str):
                    raw_text = reply
                else:
                    raw_text = "".join(str(chunk) for chunk in reply if chunk)

                generated = self._postprocess_generated(action, raw_text, variables, history)
                prepared_audio = self._prepare_speech(speaker, generated.text)
                self._generation_queue.put(
                    {
                        "text": generated.text,
                        "actions": list(generated.actions),
                        "variables": dict(generated.variables),
                        "prepared_audio": prepared_audio,
                    }
                )
            except Exception as exc:
                self._generation_queue.put(
                    {
                        "text": f"I must pause. {exc}",
                        "actions": [],
                        "variables": {},
                        "prepared_audio": None,
                    }
                )

        self._generation_thread = threading.Thread(target=worker, daemon=True)
        self._generation_thread.start()

    def _drain_generation_queue(self) -> None:
        if self._generation_queue is None:
            return

        try:
            payload = self._generation_queue.get_nowait()
        except queue.Empty:
            return

        speaker = self.dialogue.speaker
        text = str(payload.get("text") or "").strip()
        if not text:
            text = "We will discuss that in due time."

        self.variables.update(payload.get("variables") or {})
        self.insert_actions(payload.get("actions") or [])

        self.dialogue.start_say(speaker, text)
        self._record_line(speaker, text)
        self._speech_handle = self._speak(
            speaker,
            text,
            prepared_audio=payload.get("prepared_audio"),
        )
        self._generation_queue = None
        self._generation_thread = None

    def _postprocess_generated(
        self,
        action: Generate,
        raw_text: str,
        variables: dict[str, str],
        history: list[dict[str, str]],
    ) -> GeneratedReply:
        text = raw_text.strip()
        if action.postprocess is None:
            return GeneratedReply(text=text)

        processed = action.postprocess(text, variables, history)
        if isinstance(processed, GeneratedReply):
            return processed
        return GeneratedReply(text=str(processed).strip())

    def insert_actions(self, actions: Sequence[ScriptAction]) -> None:
        if not actions:
            return
        self.script[self._index : self._index] = list(actions)

    def _maybe_auto_advance(self) -> None:
        if not self.config.auto_advance:
            return
        if self.dialogue.mode != "say":
            return
        if not self.dialogue.is_complete:
            return
        if not self._speech_is_done():
            return
        self._advance_script()

    def _record_line(self, speaker: str, text: str) -> None:
        self.history.append({"speaker": speaker, "text": text})

    def _prepare_speech(self, speaker: str, text: str) -> Any | None:
        if self.voice_manager is None:
            return None
        prepare = getattr(self.voice_manager, "prepare", None)
        if prepare is None:
            return None
        try:
            return prepare(speaker, text)
        except Exception:
            return None

    def _speak(self, speaker: str, text: str, prepared_audio: Any | None = None) -> Any | None:
        if self.voice_manager is None:
            return None
        speak = getattr(self.voice_manager, "speak", None)
        if speak is None:
            return None
        try:
            return speak(speaker, text, prepared_audio=prepared_audio)
        except Exception:
            return None

    def _speech_is_done(self) -> bool:
        if self._speech_handle is None:
            return True
        is_done = getattr(self._speech_handle, "is_done", None)
        if is_done is not None:
            try:
                return bool(is_done())
            except Exception:
                return True
        done = getattr(self._speech_handle, "done", None)
        if done is not None:
            return bool(done)
        return True

    def close(self) -> None:
        if self.voice_manager is not None:
            stop = getattr(self.voice_manager, "stop", None)
            if stop is not None:
                try:
                    stop()
                except Exception:
                    pass
        if self._root is not None:
            self._root.destroy()
            self._root = None

    def _format(self, value: str) -> str:
        try:
            return value.format_map(_SafeVariables(self.variables))
        except (KeyError, ValueError):
            return value


class _SafeVariables(dict[str, str]):
    def __missing__(self, key: str) -> str:
        return "{" + key + "}"