// ============================================================
// provider.ts — 自定义更新 Provider
//
// 封装与自有版本检查 API 的交互逻辑，
// 返回 electron-updater 格式的 UpdateInfo。
// ============================================================

import { app } from 'electron';
import { createHash } from 'node:crypto';
import { URL } from 'node:url';
import { Provider } from 'electron-updater';
import type { ProviderRuntimeOptions } from 'electron-updater/out/providers/Provider';
import type { UpdateInfo, UpdateFileInfo } from 'builder-util-runtime';
import type { ResolvedUpdateFileInfo } from 'electron-updater/out/types';

import type { UpdateCheckResult } from '../../../shared/types';
import { APP_VERSION } from '../../../shared/constants/version';
import { logger } from '../logger';
import { netRequest } from '../net-request';

// ---------- 构建时注入的渠道信息 ----------

/** 构建渠道（由 build.mjs 通过 VITE_BUILD_CHANNEL 注入，Vite 编译时内联） */
export const BUILD_CHANNEL: string =
    (typeof import.meta !== 'undefined' && (import.meta as unknown as Record<string, unknown>).env
        ? ((import.meta as unknown as Record<string, unknown>).env as Record<string, string>).VITE_BUILD_CHANNEL
        : undefined)
    || process.env.VITE_BUILD_CHANNEL
    || 'stable';

/** 构建版本类型（由 build.mjs 通过 VITE_BUILD_EDITION 注入） */
export const BUILD_EDITION: string =
    (typeof import.meta !== 'undefined' && (import.meta as unknown as Record<string, unknown>).env
        ? ((import.meta as unknown as Record<string, unknown>).env as Record<string, string>).VITE_BUILD_EDITION
        : undefined)
    || process.env.VITE_BUILD_EDITION
    || 'personal';

// ---------- 设备指纹（稳定的机器标识，用于灰度分组）----------

let _deviceFingerprint: string | null = null;

/** 获取设备指纹（基于机器特定信息的 SHA-256 前 16 位） */
export function getDeviceFingerprint(): string {
    if (_deviceFingerprint) return _deviceFingerprint;

    try {
        const parts = [
            process.platform,
            process.arch,
            app.getPath('home'),
        ];
        _deviceFingerprint = createHash('sha256')
            .update(parts.join('|'))
            .digest('hex')
            .slice(0, 16);
    } catch {
        _deviceFingerprint = 'unknown-device';
    }

    return _deviceFingerprint;
}

// ---------- 配置 ----------

export function getApiBaseUrl(): string {
    const url = (process.env.UPDATE_API_URL || 'https://www.heixiu.com').trim();
    console.log(`[updater] UPDATE_API_URL=${process.env.UPDATE_API_URL} → 使用: ${url}`);
    return url;
}

// ============================================================
// HeiXiuProvider
// ============================================================

export class HeiXiuProvider extends Provider<UpdateInfo> {
    private apiBaseUrl: string;
    /** 短时缓存：避免 checkForUpdates 预检 + electron-updater 内部调用导致两次 API 请求 */
    private _cachedResult: { data: UpdateInfo; ts: number } | null = null;

    constructor(runtimeOptions: ProviderRuntimeOptions) {
        super(runtimeOptions);
        this.apiBaseUrl = getApiBaseUrl();
    }

    /**
     * 调用自有版本检查 API，返回 electron-updater 格式的 UpdateInfo。
     * blockMapSize > 0 时 electron-updater 自动启用差分下载。
     * 无更新时返回当前版本号（APP_VERSION）。
     */
    async getLatestVersion(): Promise<UpdateInfo> {
        // 短时缓存（500ms）：预检和 electron-updater 内部调用共享同一结果
        if (this._cachedResult && Date.now() - this._cachedResult.ts < 500) {
            return this._cachedResult.data;
        }
        const data = await this._doGetLatestVersion();
        this._cachedResult = { data, ts: Date.now() };
        return data;
    }

    private async _doGetLatestVersion(): Promise<UpdateInfo> {
        const { data } = await netRequest.get<{ code: number; data?: UpdateCheckResult } & UpdateCheckResult>(
            '/api/v1/update/check',
            {
                baseURL: this.apiBaseUrl,
                params: {
                    platform: process.platform,
                    version: APP_VERSION,
                    channel: BUILD_CHANNEL,
                    edition: BUILD_EDITION,
                    deviceFingerprint: getDeviceFingerprint(),
                },
            },
        );

        // 兼容两种 API 响应格式
        const result: UpdateCheckResult =
            (data as { data?: UpdateCheckResult }).data ?? (data as UpdateCheckResult);

        // 无更新 → 返回当前版本号
        if (!result.hasUpdate) {
            return {
                version: APP_VERSION,
                files: [],
                path: '',
                sha512: '',
                releaseDate: new Date().toISOString(),
            };
        }

        const file: UpdateFileInfo = {
            url: result.downloadUrl,
            sha512: result.sha512,
            size: result.fileSize,
        };

        // 后端 API 返回 blockMapSize 时启用增量更新
        if (result.blockMapSize) {
            file.blockMapSize = result.blockMapSize;
        }

        logger.info('updater', 'Provider 获取到新版本', {
            latestVersion: result.latestVersion,
            hasBlockmap: file.blockMapSize != null,
        });

        return {
            version: result.latestVersion,
            files: [file],
            path: result.downloadUrl,
            sha512: result.sha512,
            releaseDate: result.releaseDate,
            releaseNotes: result.changelog,
        };
    }

    /**
     * 将 UpdateInfo 中的相对路径解析为完整的下载 URL。
     * electron-updater 在下载前调用此方法。
     */
    resolveFiles(updateInfo: UpdateInfo): Array<ResolvedUpdateFileInfo> {
        return updateInfo.files.map((f) => {
            // 使用 downloadUrl 作为 base URL 来解析文件路径
            const baseUrl = new URL(updateInfo.path);
            const fileUrl = new URL(f.url, baseUrl.origin);
            return {
                url: fileUrl,
                info: f,
            };
        });
    }
}