import 'dart:math' as math;

import 'package:flutter/material.dart';
import 'package:flutter/scheduler.dart';
import 'package:wolf_dart/classes/coordinate_2d.dart';
import 'package:wolf_dart/classes/matrix.dart';
import 'package:wolf_dart/features/difficulty/difficulty.dart';
import 'package:wolf_dart/features/entities/collectible.dart';
import 'package:wolf_dart/features/entities/door_manager.dart';
import 'package:wolf_dart/features/entities/enemies/enemy.dart';
import 'package:wolf_dart/features/entities/entity.dart';
import 'package:wolf_dart/features/entities/entity_registry.dart';
import 'package:wolf_dart/features/input/input_manager.dart';
import 'package:wolf_dart/features/map/wolf_map.dart';
import 'package:wolf_dart/features/player/player.dart';
import 'package:wolf_dart/features/renderer/raycast_painter.dart';
import 'package:wolf_dart/features/renderer/weapon_painter.dart';
import 'package:wolf_dart/features/ui/hud.dart';
import 'package:wolf_dart/sprite_gallery.dart';

class WolfRenderer extends StatefulWidget {
  const WolfRenderer({
    super.key,
    required this.difficulty,
    this.showSpriteGallery = false,
    this.isDemo = true,
  });

  final Difficulty difficulty;
  final bool showSpriteGallery;
  final bool isDemo;

  @override
  State<WolfRenderer> createState() => _WolfRendererState();
}

class _WolfRendererState extends State<WolfRenderer>
    with SingleTickerProviderStateMixin {
  final InputManager inputManager = InputManager();
  final DoorManager doorManager = DoorManager();

  late Ticker _gameLoop;
  final FocusNode _focusNode = FocusNode();
  late WolfMap gameMap;
  late Matrix<int> currentLevel;

  final double fov = math.pi / 3;

  late Player player;

  bool _isLoading = true;

  double damageFlashOpacity = 0.0;

  List<Entity> entities = [];

  @override
  void initState() {
    super.initState();
    _initGame(demo: widget.isDemo);
  }

  Future<void> _initGame({bool demo = true}) async {
    gameMap = demo ? await WolfMap.loadDemo() : await WolfMap.load();
    currentLevel = gameMap.levels[0].wallGrid;

    doorManager.initDoors(currentLevel);

    final Matrix<int> objectLevel = gameMap.levels[0].objectGrid;

    for (int y = 0; y < 64; y++) {
      for (int x = 0; x < 64; x++) {
        int objId = objectLevel[y][x];

        if (objId >= 19 && objId <= 22) {
          double spawnAngle = 0.0;
          switch (objId) {
            case 19:
              spawnAngle = 3 * math.pi / 2;
              break;
            case 20:
              spawnAngle = 0.0;
              break;
            case 21:
              spawnAngle = math.pi / 2;
              break;
            case 22:
              spawnAngle = math.pi;
              break;
          }
          player = Player(
            x: x + 0.5,
            y: y + 0.5,
            angle: spawnAngle,
          );
        } else {
          Entity? newEntity = EntityRegistry.spawn(
            objId,
            x + 0.5,
            y + 0.5,
            widget.difficulty.level,
            gameMap.sprites.length,
          );

          if (newEntity != null) {
            entities.add(newEntity);
          }
        }
      }
    }

    for (int y = 0; y < 64; y++) {
      for (int x = 0; x < 64; x++) {
        int id = currentLevel[y][x];
        if ((id >= 1 && id <= 63) || (id >= 90 && id <= 101)) {
          // Leave walls and doors solid
        } else {
          currentLevel[y][x] = 0;
        }
      }
    }

    _bumpPlayerIfStuck();
    _gameLoop = createTicker(_tick)..start();
    _focusNode.requestFocus();

    setState(() {
      _isLoading = false;
    });
  }

  @override
  void dispose() {
    _gameLoop.dispose();
    _focusNode.dispose();
    super.dispose();
  }

  void _bumpPlayerIfStuck() {
    int pX = player.x.toInt();
    int pY = player.y.toInt();

    if (pY < 0 ||
        pY >= currentLevel.length ||
        pX < 0 ||
        pX >= currentLevel[0].length ||
        currentLevel[pY][pX] > 0) {
      double shortestDist = double.infinity;
      Coordinate2D nearestSafeSpot = Coordinate2D(1.5, 1.5);

      for (int y = 0; y < currentLevel.length; y++) {
        for (int x = 0; x < currentLevel[y].length; x++) {
          if (currentLevel[y][x] == 0) {
            Coordinate2D safeSpot = Coordinate2D(x + 0.5, y + 0.5);
            double dist = safeSpot.distanceTo(player.position);

            if (dist < shortestDist) {
              shortestDist = dist;
              nearestSafeSpot = safeSpot;
            }
          }
        }
      }
      player.x = nearestSafeSpot.x;
      player.y = nearestSafeSpot.y;
    }
  }

  bool _isWalkable(int x, int y) {
    if (currentLevel[y][x] == 0) return true;
    if (currentLevel[y][x] >= 90) {
      return doorManager.isDoorOpenEnough(x, y);
    }
    return false;
  }

  // --- ORCHESTRATOR ---
  void _tick(Duration elapsed) {
    // 1. Process intentions and receive movement vectors
    final inputResult = _processInputs(elapsed);

    doorManager.update(elapsed);

    // 2. Explicit State Updates
    player.updateWeaponSwitch();

    player.angle += inputResult.dAngle;

    // Keep the angle neatly clamped between 0 and 2*PI
    if (player.angle < 0) player.angle += 2 * math.pi;
    if (player.angle >= 2 * math.pi) player.angle -= 2 * math.pi;

    _applyMovementAndCollision(inputResult.movement);
    _updateEntities(elapsed);

    // Explicit reassignment from a pure(r) function
    damageFlashOpacity = _calculateScreenEffects(damageFlashOpacity);

    // 3. Combat
    player.updateWeapon(
      currentTime: elapsed.inMilliseconds,
      entities: entities,
      isWalkable: _isWalkable,
    );

    // 4. Render
    setState(() {});
  }

  void _takeDamage(int damage) {
    player.takeDamage(damage);
    damageFlashOpacity = 0.5;
  }

  // Returns a Record containing both movement delta and rotation delta
  ({Coordinate2D movement, double dAngle}) _processInputs(Duration elapsed) {
    inputManager.update();

    const double moveSpeed = 0.16;
    const double turnSpeed = 0.12;

    Coordinate2D movement = const Coordinate2D(0, 0);
    double dAngle = 0.0;

    if (inputManager.requestedWeapon != null) {
      player.requestWeaponSwitch(inputManager.requestedWeapon!);
    }

    if (inputManager.isFiring) {
      player.fire(elapsed.inMilliseconds);
    }

    // Calculate intended rotation
    if (inputManager.isTurningLeft) dAngle -= turnSpeed;
    if (inputManager.isTurningRight) dAngle += turnSpeed;

    // Calculate intended movement based on CURRENT angle
    Coordinate2D forwardVec = Coordinate2D(
      math.cos(player.angle),
      math.sin(player.angle),
    );

    if (inputManager.isMovingForward) {
      movement += forwardVec * moveSpeed;
    }
    if (inputManager.isMovingBackward) {
      movement -= forwardVec * moveSpeed;
    }

    if (inputManager.isInteracting) {
      doorManager.handleInteraction(
        player.x,
        player.y,
        player.angle,
      );
    }

    return (movement: movement, dAngle: dAngle);
  }

  void _applyMovementAndCollision(Coordinate2D movement) {
    const double margin = 0.3;

    // Calculate the intended new position
    Coordinate2D newPos = player.position + movement;

    // Check X axis independently (allows for sliding along walls)
    if (movement.x != 0) {
      int checkX = (movement.x > 0)
          ? (newPos.x + margin).toInt()
          : (newPos.x - margin).toInt();

      if (_isWalkable(checkX, player.position.y.toInt())) {
        player.x = newPos.x;
      }
    }

    // Check Y axis independently
    if (movement.y != 0) {
      int checkY = (movement.y > 0)
          ? (newPos.y + margin).toInt()
          : (newPos.y - margin).toInt();

      if (_isWalkable(player.position.x.toInt(), checkY)) {
        player.y = newPos.y;
      }
    }
  }

  void _updateEntities(Duration elapsed) {
    List<Entity> itemsToRemove = [];

    for (Entity entity in entities) {
      if (entity is Enemy) {
        entity.update(
          elapsedMs: elapsed.inMilliseconds,
          playerPosition: player.position,
          isWalkable: _isWalkable,
          onDamagePlayer: _takeDamage,
        );
      } else if (entity is Collectible) {
        if (player.position.distanceTo(entity.position) < 0.5) {
          if (player.tryPickup(entity)) {
            itemsToRemove.add(entity);
          }
        }
      }
    }

    if (itemsToRemove.isNotEmpty) {
      entities.removeWhere((e) => itemsToRemove.contains(e));
    }
  }

  // Takes an input and returns a value instead of implicitly changing state
  double _calculateScreenEffects(double currentOpacity) {
    if (currentOpacity > 0) {
      return math.max(0.0, currentOpacity - 0.05);
    }
    return currentOpacity;
  }

  @override
  Widget build(BuildContext context) {
    if (_isLoading) {
      return const Center(child: CircularProgressIndicator(color: Colors.teal));
    }

    if (widget.showSpriteGallery) {
      return SpriteGallery(sprites: gameMap.sprites);
    }

    return Scaffold(
      backgroundColor: Colors.black,
      body: KeyboardListener(
        focusNode: _focusNode,
        autofocus: true,
        onKeyEvent: (_) {},
        child: Column(
          children: [
            Expanded(
              child: LayoutBuilder(
                builder: (context, constraints) {
                  return Center(
                    child: AspectRatio(
                      aspectRatio: 16 / 10,
                      child: Stack(
                        children: [
                          CustomPaint(
                            size: Size(
                              constraints.maxWidth,
                              constraints.maxHeight,
                            ),
                            painter: RaycasterPainter(
                              map: currentLevel,
                              textures: gameMap.textures,
                              player: player,
                              fov: fov,
                              doorOffsets: doorManager.getOffsetsForRenderer(),
                              entities: entities,
                              sprites: gameMap.sprites,
                            ),
                          ),
                          Positioned(
                            bottom: -20,
                            left: 0,
                            right: 0,
                            child: Center(
                              child: Transform.translate(
                                offset: Offset(
                                  // Replaced hidden step variables with a direct intention check!
                                  (inputManager.isMovingForward ||
                                          inputManager.isMovingBackward)
                                      ? math.sin(
                                              DateTime.now()
                                                      .millisecondsSinceEpoch /
                                                  100,
                                            ) *
                                            12
                                      : 0,
                                  player.weaponAnimOffset,
                                ),
                                child: SizedBox(
                                  width: 500,
                                  height: 500,
                                  child: CustomPaint(
                                    painter: WeaponPainter(
                                      sprite:
                                          gameMap.sprites[player
                                              .currentWeapon
                                              .currentSprite],
                                    ),
                                  ),
                                ),
                              ),
                            ),
                          ),
                          if (damageFlashOpacity > 0)
                            Positioned.fill(
                              child: Container(
                                color: Colors.red.withValues(
                                  alpha: damageFlashOpacity,
                                ),
                              ),
                            ),
                        ],
                      ),
                    ),
                  );
                },
              ),
            ),
            Hud(player: player),
          ],
        ),
      ),
    );
  }
}