//
//  DouyinShare.swift
//  ylgamehall
//
//  抖音分享 SharePlatform 实现（Phase 4.D 完整）。
//
//  移植 msext DouyinShareManager.m:201-269 shareImageToDouyin 流程：
//    1. 拿图片源（type=2 → ImageProvider.captureScreenshot；其它 →
//       ImageProvider.downloadRemote）；type=1 链接 → 抖音不原生支持纯链接，
//       退化为截屏分享（msext 行为：所有 H5 分享到抖音都走图片）
//    2. PhotoLibrarySaver.save 保存到相册（addOnly 权限）
//    3. UIPasteboard 兜底放图片数据，供抖音读取
//    4. 按顺序尝试 snssdk1128://camera / publish / share/image / 基础 scheme，
//       canOpenURL 命中即调起
//    5. 调起即视为 success（URL Scheme 单向无返回）
//
//  **不依赖抖音 SDK**。
//

import UIKit
import os.log

@MainActor
public final class DouyinShare: SharePlatform {

    public static let shared = DouyinShare()

    private static let log = Logger(subsystem: "ylgamehall", category: "DouyinShare")

    public let name = "Douyin"

    public var isInstalled: Bool {
        guard let url = URL(string: "snssdk1128://") else { return false }
        return UIApplication.shared.canOpenURL(url)
    }

    public init() {}

    public func share(_ content: ShareContent, scene: ShareScene) async -> ShareResult {
        guard isInstalled else { return .notInstalled(platform: name) }

        // 1. 拿图片源
        let image: UIImage
        do {
            switch content.type {
            case "2":
                image = try ImageProvider.captureScreenshot()
            case "1":
                // 抖音不支持纯链接分享，退化为当前屏截屏（msext 行为）
                Self.log.debug("DouyinShare: type=1 链接，退化为截屏分享")
                image = try ImageProvider.captureScreenshot()
            default:
                // type == 其它 → 远端图片 URL
                image = try await ImageProvider.downloadRemote(content.webpageUrl)
            }
        } catch {
            Self.log.error("DouyinShare: 获取图片失败 \(error.localizedDescription, privacy: .public)")
            return .failed(reason: "获取图片失败: \(error.localizedDescription)")
        }

        // 2. 保存到相册（含权限检查）
        do {
            try await PhotoLibrarySaver.save(image)
        } catch PhotoLibrarySaverError.permissionDenied {
            Self.log.warning("DouyinShare: 相册写入权限被拒")
            return .failed(reason: "相册写入权限被拒")
        } catch {
            Self.log.error("DouyinShare: 保存相册失败 \(error.localizedDescription, privacy: .public)")
            return .failed(reason: "保存相册失败: \(error.localizedDescription)")
        }

        // 3. 同时放剪贴板兜底（msext 行为：抖音从剪贴板读图）
        UIPasteboard.general.image = image

        // 4. 按 msext 顺序尝试多个 URL Scheme
        let schemes = [
            "snssdk1128://camera",         // 抖音拍摄界面
            "snssdk1128://publish",        // 发布界面
            "snssdk1128://share/image",    // 图片分享（可能已废弃但保留）
            "snssdk1128://"                // 兜底基础 scheme
        ]

        for schemeString in schemes {
            guard let url = URL(string: schemeString),
                  UIApplication.shared.canOpenURL(url)
            else { continue }
            Self.log.debug("DouyinShare open: \(schemeString, privacy: .public)")
            let opened = await UIApplication.shared.open(url)
            if opened { return .success }
        }

        return .failed(reason: "所有抖音 URL Scheme 都调起失败")
    }
}