/// Active gameplay screen for the Flutter host.
library;

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:wolf_3d_dart/wolf_3d_engine.dart';
import 'package:wolf_3d_dart/wolf_3d_renderer.dart';
import 'package:wolf_3d_flutter/wolf_3d_flutter.dart';
import 'package:wolf_3d_renderer/wolf_3d_ascii_renderer.dart';
import 'package:wolf_3d_renderer/wolf_3d_flutter_renderer.dart';
import 'package:wolf_3d_renderer/wolf_3d_glsl_renderer.dart';

enum _RendererMode {
  software,
  ascii,
  glsl,
}

/// Launches a [WolfEngine] via [Wolf3d] and exposes renderer/input integrations.
class GameScreen extends StatefulWidget {
  /// Shared application facade owning the engine, audio, and input.
  final Wolf3d wolf3d;

  /// Creates a gameplay screen driven by [wolf3d].
  const GameScreen({
    required this.wolf3d,
    super.key,
  });

  @override
  State<GameScreen> createState() => _GameScreenState();
}

class _GameScreenState extends State<GameScreen> {
  late final WolfEngine _engine;
  _RendererMode _rendererMode = _RendererMode.software;
  AsciiTheme _asciiTheme = AsciiThemes.blocks;

  @override
  void initState() {
    super.initState();
    _engine = widget.wolf3d.launchEngine(
      onGameWon: () {
        _engine.difficulty = null;
        widget.wolf3d.clearActiveDifficulty();
        Navigator.of(context).pop();
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    return PopScope(
      canPop: _engine.difficulty != null,
      onPopInvokedWithResult: (didPop, _) {
        if (!didPop && _engine.difficulty == null) {
          widget.wolf3d.input.queueBackAction();
        }
      },
      child: Scaffold(
        body: LayoutBuilder(
          builder: (context, constraints) {
            return Listener(
              onPointerDown: (event) {
                widget.wolf3d.input.onPointerDown(event);
              },
              onPointerUp: widget.wolf3d.input.onPointerUp,
              onPointerMove: widget.wolf3d.input.onPointerMove,
              onPointerHover: widget.wolf3d.input.onPointerMove,
              child: Stack(
                children: [
                  _buildRenderer(),

                  if (!_engine.isInitialized)
                    Container(
                      color: Colors.black,
                      child: const Center(
                        child: Column(
                          mainAxisSize: MainAxisSize.min,
                          children: [
                            CircularProgressIndicator(color: Colors.teal),
                            SizedBox(height: 20),
                            Text(
                              "GET PSYCHED!",
                              style: TextStyle(
                                color: Colors.teal,
                                fontFamily: 'monospace',
                              ),
                            ),
                          ],
                        ),
                      ),
                    ),

                  // A second full-screen overlay keeps the presentation simple while
                  // the engine is still warming up or decoding the first frame.
                  if (!_engine.isInitialized)
                    Container(
                      color: Colors.black,
                      child: const Center(
                        child: CircularProgressIndicator(color: Colors.teal),
                      ),
                    ),

                  Positioned(
                    top: 16,
                    right: 16,
                    child: Text(
                      'TAB: ${_modeLabel(_rendererMode)}   T: ${_asciiTheme.name}   `: FPS ${_engine.showFpsCounter ? 'On' : 'Off'}',
                      style: TextStyle(
                        color: Colors.white.withValues(alpha: 0.5),
                      ),
                    ),
                  ),
                ],
              ),
            );
          },
        ),
      ),
    );
  }

  Widget _buildRenderer() {
    // Keep all renderers behind the same engine so mode switching does not
    // reset level state or audio playback.
    switch (_rendererMode) {
      case _RendererMode.software:
        return WolfFlutterRenderer(
          engine: _engine,
          onKeyEvent: _handleRendererKeyEvent,
        );
      case _RendererMode.ascii:
        return WolfAsciiRenderer(
          engine: _engine,
          theme: _asciiTheme,
          onKeyEvent: _handleRendererKeyEvent,
        );
      case _RendererMode.glsl:
        return WolfGlslRenderer(
          engine: _engine,
          onKeyEvent: _handleRendererKeyEvent,
          onUnavailable: _onGlslUnavailable,
        );
    }
  }

  void _handleRendererKeyEvent(KeyEvent event) {
    if (event is! KeyDownEvent) {
      return;
    }

    if (event.logicalKey == LogicalKeyboardKey.tab) {
      setState(_cycleRendererMode);
      return;
    }

    if (event.logicalKey == LogicalKeyboardKey.backquote ||
        event.character == '`') {
      setState(_toggleFpsCounter);
      return;
    }

    if (event.logicalKey == LogicalKeyboardKey.keyT ||
        event.character == 't' ||
        event.character == 'T') {
      setState(_cycleAsciiTheme);
    }
  }

  void _cycleRendererMode() {
    switch (_rendererMode) {
      case _RendererMode.software:
        _rendererMode = _RendererMode.ascii;
        break;
      case _RendererMode.ascii:
        _rendererMode = _RendererMode.glsl;
        break;
      case _RendererMode.glsl:
        _rendererMode = _RendererMode.software;
        break;
    }
  }

  void _onGlslUnavailable() {
    if (!mounted || _rendererMode != _RendererMode.glsl) {
      return;
    }
    setState(() {
      _rendererMode = _RendererMode.software;
    });
  }

  void _toggleFpsCounter() {
    _engine.showFpsCounter = !_engine.showFpsCounter;
  }

  void _cycleAsciiTheme() {
    _asciiTheme = AsciiThemes.nextOf(_asciiTheme);
  }

  String _modeLabel(_RendererMode mode) {
    switch (mode) {
      case _RendererMode.software:
        return 'Software';
      case _RendererMode.ascii:
        return 'ASCII';
      case _RendererMode.glsl:
        return 'GLSL';
    }
  }
}