import SwiftUI

/// 手表主页：一键录音、今日数、最近录音；录完传 iPhone，整理在手机端完成。
struct ContentView: View {
    @EnvironmentObject private var sessionManager: WatchSessionManager
    @StateObject private var recorder = WatchRecorder()
    @State private var phase = Phase.idle
    @State private var notes = WatchStore.load()
    @State private var lastURL: URL?

    enum Phase {
        case idle, recording, sending, sent, error(String)
    }

    var body: some View {
        ScrollView {
            VStack(spacing: 12) {
                switch phase {
                case .idle:
                    recordButton
                    Text("今日速记 \(sessionManager.todayCount) 条")
                        .font(.caption2)
                        .foregroundStyle(.secondary)
                case .recording:
                    recordingView
                case .sending:
                    ProgressView("正在传到 iPhone…")
                case .sent:
                    Label("已传到 iPhone", systemImage: "checkmark.circle.fill")
                        .font(.caption)
                        .foregroundStyle(.green)
                    Button("再录一条") { phase = .idle }
                        .font(.caption)
                case .error(let message):
                    Text(message)
                        .font(.caption)
                        .foregroundStyle(.red)
                        .multilineTextAlignment(.center)
                    if let url = lastURL {
                        Button("重试传输") { send(url: url) }
                            .font(.caption)
                    }
                    Button("返回") { phase = .idle }
                        .font(.caption)
                }

                if !notes.isEmpty {
                    Divider()
                    ForEach(notes.prefix(5)) { note in
                        HStack {
                            Text(note.createdAt, format: .dateTime.hour().minute())
                                .font(.caption2)
                            Spacer()
                            Text(formatTime(note.duration))
                                .font(.caption2)
                                .foregroundStyle(.secondary)
                            Image(systemName: note.sent ? "checkmark.icloud.fill" : "paperplane")
                                .font(.caption2)
                                .foregroundStyle(note.sent ? .green : .secondary)
                        }
                    }
                }
            }
            .padding()
        }
    }

    private var recordButton: some View {
        Button {
            Task {
                guard await recorder.requestPermission() else {
                    phase = .error("没有麦克风权限，请在手表设置里开启。")
                    return
                }
                do {
                    try recorder.start()
                    phase = .recording
                } catch {
                    phase = .error("录音启动失败：\(error.localizedDescription)")
                }
            }
        } label: {
            ZStack {
                Circle().fill(Color.red)
                Image(systemName: "mic.fill")
                    .font(.title2)
                    .foregroundStyle(.white)
            }
            .frame(width: 72, height: 72)
        }
        .buttonStyle(.plain)
    }

    private var recordingView: some View {
        VStack(spacing: 10) {
            HStack(spacing: 4) {
                Circle().fill(Color.red).frame(width: 8, height: 8)
                Text("录音中 \(formatTime(recorder.elapsed))")
                    .font(.caption)
            }
            Button("停止并发送") {
                guard let url = recorder.stop() else {
                    phase = .error("录音文件没生成，请再试一次。")
                    return
                }
                lastURL = url
                send(url: url)
            }
            .font(.caption)
            .tint(.red)
        }
    }

    private func send(url: URL) {
        phase = .sending
        sessionManager.transfer(url: url) { result in
            switch result {
            case .success:
                notes.insert(WatchNote(createdAt: Date(), duration: recorder.elapsed, sent: true), at: 0)
                WatchStore.append(notes[0])
                phase = .sent
            case .failure(let error):
                phase = .error(error.localizedDescription)
            }
        }
    }

    private func formatTime(_ time: TimeInterval) -> String {
        let total = Int(time)
        return String(format: "%d:%02d", total / 60, total % 60)
    }
}