/**
 * 整个APP的环境配置逻辑
 */
import { sys } from "cc";
import { DEBUG, EDITOR, PREVIEW } from "cc/env"; 
import { Env, AppConfigShape } from "./env";
import { devConfig } from "./dev";
import { testConfig } from "./test";
import { prodConfig } from "./prod";

type PartialEndpoints = Partial<AppConfigShape["endpoints"]>;

const LS_ENV_KEY = "app_env";
const LS_OVERRIDE_KEY = "app_endpoints_override"; // 存JSON字符串

export class AppConfig {
  private static _I: AppConfig | null = null;
  static get I(): AppConfig {
    if (!AppConfig._I) AppConfig._I = new AppConfig();
    return AppConfig._I;
  }

  private _cfg!: AppConfigShape;

  private constructor() {
    const env = this.detectEnv();
    this._cfg = this.byEnv(env);

    // 运行时覆盖：query > localStorage
    // this.applyQueryOverride();
    // this.applyLocalOverride();
  }

  public getEnv(): Env { return this._cfg.env; }
  public isDev(): boolean  { return this._cfg.env === Env.Dev; }
  public isTest(): boolean { return this._cfg.env === Env.Test; }
  public isProd(): boolean { return this._cfg.env === Env.Prod; }  
  get endpoints() { return this._cfg.endpoints; }

  /** 切换环境（开发工具用） */
  public switchEnv(env: Env) {
    this._cfg = this.byEnv(env);
    sys.localStorage.setItem(LS_ENV_KEY, env);
  }

  /** 运行时局部覆盖 endpoints（紧急切换） */
  public overrideEndpoints(patch: PartialEndpoints) {
    this._cfg = {
      ...this._cfg,
      endpoints: { ...this._cfg.endpoints, ...patch, cdn: { ...this._cfg.endpoints.cdn, ...(patch.cdn || {}) } }
    };
    sys.localStorage.setItem(LS_OVERRIDE_KEY, JSON.stringify(patch));
  }

  /** 清除覆盖，回到纯环境配置 */
  public clearOverrides() {
    sys.localStorage.removeItem(LS_OVERRIDE_KEY);
    this._cfg = this.byEnv(this._cfg.env);
  }

  /** 获取 HTTP 基础地址
   * @param stripTrailingSlash 是否去掉末尾斜杠，默认 true
   */
  public getHttpBase(stripTrailingSlash: boolean = true): string {
    const raw = this._cfg.endpoints.httpBase || "";
    if (stripTrailingSlash) {
      return raw.replace(/\/+$/, "");
    }
    // 保证有一个结尾斜杠
    return raw.endsWith("/") ? raw : raw + "/";
  }  

  // ------------ 内部 ------------
  private byEnv(env: Env): AppConfigShape {
    switch (env) {
      case Env.Dev:  return devConfig;
      case Env.Test: return testConfig;
      default:       return prodConfig;
    }
  }

  private isEnv(x: any): x is Env {
    return x === Env.Dev || x === Env.Test || x === Env.Prod;
  }

  /** 默认环境：优先 localStorage，再看 EDITOR/DEBUG，最后 prod */
  private detectEnv(): Env {
    const saved = sys.localStorage.getItem(LS_ENV_KEY) as Env | null;
    if (saved && this.isEnv(saved)) {
      return saved;
    }
    // 编辑器/预览时默认 dev
    if (EDITOR || (PREVIEW && DEBUG)) return Env.Dev;
    // 调试构建默认 test 
    if (DEBUG) return Env.Test;  
    // 发行构建默认 prod                      
    return Env.Prod;                                   
  }

  private applyLocalOverride() {
    const raw = sys.localStorage.getItem(LS_OVERRIDE_KEY);
    if (raw) {
      try {
        this.overrideEndpoints(JSON.parse(raw));
      } catch { /* ignore */ }
    }
  }

  /** 支持浏览器 query 覆盖：?env=test&http=...&socket=...&cdn_bgm=... */
  private applyQueryOverride() {
    if (!sys.isBrowser) return;
    const qs = new URLSearchParams(window.location.search);
    const qEnv = qs.get("env") as Env | null;
    if (qEnv && this.isEnv(qEnv)) {
      this._cfg = this.byEnv(qEnv);
      sys.localStorage.setItem(LS_ENV_KEY, qEnv);
    }
    const patch: PartialEndpoints = {};
    if (qs.get("http"))   (patch.httpBase   = qs.get("http")!);
    if (qs.get("socket")) (patch.socketBase = qs.get("socket")!);
    const cdnPatch: any = {};
    if (qs.get("cdn_bgm"))     cdnPatch.bgm = qs.get("cdn_bgm");
    if (qs.get("cdn_zhen"))    cdnPatch.zhenCang = qs.get("cdn_zhen");
    if (qs.get("cdn_bgvideo")) cdnPatch.bgVideo = qs.get("cdn_bgvideo");
    if (Object.keys(cdnPatch).length) (patch.cdn = cdnPatch);
    if (Object.keys(patch).length) this.overrideEndpoints(patch);
  }
}