/**
 * 场景物理与环境的配置定义（T-WEB-015）。
 *
 * 职责划分：**服务端只存参数、不跑物理**；仿真在客户端（Windows 端用 Godot 内置物理：
 * RigidBody3D / Area3D 风场 / PhysicsServer3D）。因此这里只做
 * "结构校验 + 默认值 + 边界收敛"，保证下发给客户端的参数一定可解释。
 */

export interface Vec3 {
  x: number;
  y: number;
  z: number;
}

/** 风：基础风 + 阵风（正弦叠加） */
export interface WindConfig {
  base: Vec3;
  /** 阵风幅度（米/秒，0 表示无阵风；上限 100） */
  gustAmplitude: number;
  /** 阵风频率（Hz，0.01~5） */
  gustFrequency: number;
  /** 阵风方向（上限 ±1） */
  gustDirection: Vec3;
  /** 世界坐标 or 场景局部坐标 */
  space: 'world' | 'local';
}

export interface GroundConfig {
  /** 摩擦系数 0~1 */
  friction: number;
  /** 弹性 0~1 */
  restitution: number;
  /** 可行走坡度上限（度）0~89 */
  slopeLimit: number;
}

export interface EnvironmentConfig {
  /** 环境光颜色（#RRGGBB） */
  ambientColor: string;
  /** 环境光强度 0~4 */
  ambientIntensity: number;
  /** 雾浓度 0~1（0 = 关闭） */
  fogDensity: number;
}

export interface SpawnPoint {
  x: number;
  y: number;
  z: number;
  /** 朝向（度，绕 Y 轴） */
  yaw: number;
}

export interface CameraConfig {
  mode: 'follow' | 'fixed' | 'orbit';
  distance: number;
  height: number;
}

export interface SceneConfig {
  physics: {
    /** 重力向量（米/秒^2），默认 (0,-9.8,0) */
    gravity: Vec3;
    wind: WindConfig;
    ground: GroundConfig;
    /** 碰撞体来源：auto（按 GLB 命名约定）| mesh（三角网）| none */
    colliders: 'auto' | 'mesh' | 'none';
  };
  environment: EnvironmentConfig;
  spawnPoints: SpawnPoint[];
  camera: CameraConfig;
}

export const SCENE_CONFIG_DEFAULTS: SceneConfig = {
  physics: {
    gravity: { x: 0, y: -9.8, z: 0 },
    wind: {
      base: { x: 0, y: 0, z: 0 },
      gustAmplitude: 0,
      gustFrequency: 0.2,
      gustDirection: { x: 1, y: 0, z: 0 },
      space: 'world',
    },
    ground: { friction: 0.6, restitution: 0, slopeLimit: 45 },
    colliders: 'auto',
  },
  environment: { ambientColor: '#8fb4ff', ambientIntensity: 1, fogDensity: 0 },
  spawnPoints: [{ x: 0, y: 0, z: 0, yaw: 0 }],
  camera: { mode: 'follow', distance: 4.5, height: 1.6 },
};

function num(value: unknown, fallback: number, min: number, max: number): number {
  const parsed = typeof value === 'number' && Number.isFinite(value) ? value : fallback;
  return Math.min(max, Math.max(min, parsed));
}

function vec3(value: unknown, fallback: Vec3, limit = 1000): Vec3 {
  const raw = (value ?? {}) as Partial<Vec3>;
  return {
    x: num(raw.x, fallback.x, -limit, limit),
    y: num(raw.y, fallback.y, -limit, limit),
    z: num(raw.z, fallback.z, -limit, limit),
  };
}

function hexColor(value: unknown, fallback: string): string {
  return typeof value === 'string' && /^#[0-9a-fA-F]{6}$/.test(value) ? value.toLowerCase() : fallback;
}

/**
 * 把任意输入收敛成合法 `SceneConfig`：缺项用默认值、越界夹紧、非法枚举回退。
 * **永不抛错** —— 保证客户端拿到的参数一定可解释。
 */
export function normalizeSceneConfig(input: unknown): SceneConfig {
  const raw = (input ?? {}) as Partial<SceneConfig>;
  const physics = (raw.physics ?? {}) as Partial<SceneConfig['physics']>;
  const wind = (physics.wind ?? {}) as Partial<WindConfig>;
  const ground = (physics.ground ?? {}) as Partial<GroundConfig>;
  const environment = (raw.environment ?? {}) as Partial<EnvironmentConfig>;
  const camera = (raw.camera ?? {}) as Partial<CameraConfig>;
  const defaults = SCENE_CONFIG_DEFAULTS;
  const spawnPoints = Array.isArray(raw.spawnPoints) && raw.spawnPoints.length > 0
    ? raw.spawnPoints
    : defaults.spawnPoints;

  return {
    physics: {
      gravity: vec3(physics.gravity, defaults.physics.gravity, 200),
      wind: {
        base: vec3(wind.base, defaults.physics.wind.base, 100),
        gustAmplitude: num(wind.gustAmplitude, defaults.physics.wind.gustAmplitude, 0, 100),
        gustFrequency: num(wind.gustFrequency, defaults.physics.wind.gustFrequency, 0.01, 5),
        gustDirection: vec3(wind.gustDirection, defaults.physics.wind.gustDirection, 1),
        space: wind.space === 'local' ? 'local' : 'world',
      },
      ground: {
        friction: num(ground.friction, defaults.physics.ground.friction, 0, 1),
        restitution: num(ground.restitution, defaults.physics.ground.restitution, 0, 1),
        slopeLimit: num(ground.slopeLimit, defaults.physics.ground.slopeLimit, 0, 89),
      },
      colliders: physics.colliders === 'mesh' || physics.colliders === 'none' ? physics.colliders : 'auto',
    },
    environment: {
      ambientColor: hexColor(environment.ambientColor, defaults.environment.ambientColor),
      ambientIntensity: num(environment.ambientIntensity, defaults.environment.ambientIntensity, 0, 4),
      fogDensity: num(environment.fogDensity, defaults.environment.fogDensity, 0, 1),
    },
    spawnPoints: spawnPoints.slice(0, 16).map((point) => {
      const item = (point ?? {}) as Partial<SpawnPoint>;
      return {
        x: num(item.x, 0, -1000, 1000),
        y: num(item.y, 0, -1000, 1000),
        z: num(item.z, 0, -1000, 1000),
        yaw: num(item.yaw, 0, -360, 360),
      };
    }),
    camera: {
      mode: camera.mode === 'fixed' || camera.mode === 'orbit' ? camera.mode : defaults.camera.mode,
      distance: num(camera.distance, defaults.camera.distance, 0.5, 50),
      height: num(camera.height, defaults.camera.height, 0, 20),
    },
  };
}