import Foundation
import Speech
import SwiftData
import WatchConnectivity

/// iPhone 端接收胶水代码：拖进 YuJi iPhone 工程即可。
/// 在 YuJiApp 启动时调用 WatchSyncService.shared.activate(modelContext:)。
/// 收到手表传来的录音文件后：拷进 AudioStorage → 系统语音识别转写 → 生成一条 VoiceNote，
/// 之后在 App 里点 AI 整理即可（和正常录音的笔记完全一样）。
final class WatchSyncService: NSObject, WCSessionDelegate, ObservableObject {
    static let shared = WatchSyncService()

    private var modelContext: ModelContext?
    private let recognizer = SFSpeechRecognizer(locale: Locale(identifier: "zh-CN"))

    func activate(modelContext: ModelContext) {
        self.modelContext = modelContext
        guard WCSession.isSupported() else { return }
        let session = WCSession.default
        session.delegate = self
        session.activate()
    }

    // MARK: - WCSessionDelegate

    func session(_ session: WCSession, activationDidCompleteWith activationState: WCSessionActivationState, error: Error?) {
        // 激活完成即可收文件
    }

    func sessionDidBecomeInactive(_ session: WCSession) {}
    func sessionDidDeactivate(_ session: WCSession) {}

    func session(_ session: WCSession, didReceive file: WCSessionFile) {
        let fileName = file.fileURL.lastPathComponent
        let destURL = AudioStorage.directory.appendingPathComponent(fileName)
        do {
            if FileManager.default.fileExists(atPath: destURL.path) {
                try FileManager.default.removeItem(at: destURL)
            }
            try FileManager.default.copyItem(at: file.fileURL, to: destURL)
        } catch {
            print("手表录音保存失败：\(error)")
            return
        }
        transcribeAndSave(audioURL: destURL, fileName: fileName)
    }

    // MARK: - 转写并建笔记

    private func transcribeAndSave(audioURL: URL, fileName: String) {
        guard let recognizer, recognizer.isAvailable else {
            // 识别暂不可用：先建一条空转写笔记，用户可在 App 里重新整理
            insertNote(title: "手表速记", transcript: "", fileName: fileName)
            return
        }
        let request = SFSpeechURLRecognitionRequest(url: audioURL)
        if recognizer.supportsOnDeviceRecognition {
            request.requiresOnDeviceRecognition = true
        }
        recognizer.recognitionTask(with: request) { [weak self] result, error in
            guard let self else { return }
            guard let result, result.isFinal else {
                if error != nil {
                    self.insertNote(title: "手表速记", transcript: "", fileName: fileName)
                }
                return
            }
            let text = result.bestTranscription.formattedString
            let title = text.count > 20 ? String(text.prefix(20)) + "…" : (text.isEmpty ? "手表速记" : text)
            self.insertNote(title: title, transcript: text, fileName: fileName)
        }
    }

    @MainActor
    private func insertNote(title: String, transcript: String, fileName: String) {
        guard let modelContext else { return }
        let note = VoiceNote(title: title, transcript: transcript, audioFileName: fileName)
        modelContext.insert(note)
        try? modelContext.save()
    }
}