//
//  BackgroundIntent.swift
//  Runner
//
//  Created by hoshizora-rin on 2024/9/19.
//

import SwiftUI
import WidgetKit

private let widgetGroupId = "group.com.zhushenwudi.lovelivemusicplayer"

struct Provider: TimelineProvider {
    func placeholder(in context: Context) -> ExampleEntry {
        sampleEntry(family: context.family, isPreview: true)
    }

    func getSnapshot(in context: Context, completion: @escaping (ExampleEntry) -> Void) {
        // 与 Flutter 一样读 App Group；isPreview 仅用于避免 Button(intent) 把添加页打成鱼骨。
        completion(readEntry(family: context.family, isPreview: true))
    }

    func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> Void) {
        // 数据由主应用写入 App Group 后主动 reload；不要让单条当前时间的
        // timeline 以 .atEnd 反复申请无意义的系统刷新预算。
        completion(Timeline(entries: [readEntry(family: context.family, isPreview: false)], policy: .never))
    }

    private func readEntry(family: WidgetFamily, isPreview: Bool) -> ExampleEntry {
        let data = UserDefaults(suiteName: widgetGroupId)
        let songName = data?.string(forKey: "songName") ?? ""
        let songArtist = data?.string(forKey: "songArtist") ?? ""
        let isFavorite = data?.bool(forKey: "songFavorite") ?? false
        let isPlaying = data?.bool(forKey: "isPlaying") ?? false
        let playText = data?.string(forKey: "playText") ?? ""
        let isShutdown = data?.bool(forKey: "isShutdown") ?? true
        let bgColor = data?.string(forKey: "bgColor") ?? "255,255,255"

        return ExampleEntry(
            date: Date(),
            widgetFamily: family,
            songName: songName,
            songArtist: songArtist,
            isFavorite: isFavorite,
            isPlaying: isPlaying,
            playText: playText,
            isShutdown: isShutdown,
            bgColor: bgColor,
            isPreview: isPreview
        )
    }
}

private func sampleEntry(family: WidgetFamily, isPreview: Bool) -> ExampleEntry {
    ExampleEntry(
        date: Date(),
        widgetFamily: family,
        songName: "",
        songArtist: "",
        isFavorite: false,
        isPlaying: false,
        playText: "",
        isShutdown: true,
        bgColor: "255,255,255",
        isPreview: isPreview
    )
}

struct ExampleEntry: TimelineEntry {
    let date: Date
    let widgetFamily: WidgetFamily
    let songName: String
    let songArtist: String
    let isFavorite: Bool
    let isPlaying: Bool
    let playText: String
    let isShutdown: Bool
    let bgColor: String
    let isPreview: Bool
}

struct HomeWidgetExampleEntryView: View {
    var entry: Provider.Entry
    var isWhiteBackground = true
    private let actionButtonSize: CGFloat = 34
    private let transportIconSize: CGFloat = 20
    
    init(entry: Provider.Entry, isWhiteBackground: Bool) {
        self.entry = entry
        self.isWhiteBackground = isWhiteBackground
    }

    var body: some View {
        let canvas = familyCanvasSize
            let cdSize: CGFloat = 140
            let coverSize: CGFloat = cdSize * 0.55
            let coverAndCdDiffSize: CGFloat = (cdSize - coverSize) / 2
            let playButtonAndCdDiffSize: CGFloat = (cdSize - 34) / 2 // width:18 + padding:8x2
            let offsetX = calcCdOffsetX(entry: entry, canvas: canvas)
            let offsetY = calcCdOffsetY(entry: entry, canvas: canvas)
            let bgColor = calcBgColor(entry: entry)
            let playText = calcPlayText(entry: entry)
            
            ZStack {
                // 填充整个布局颜色
                if isWhiteBackground {
                    Rectangle()
                        .fill(
                            AngularGradient(
                                gradient: Gradient(
                                    colors: [
                                        Color(red: 229/255, green: 233/255, blue: 235/255),
                                        Color(red: 219/255, green: 223/255, blue: 225/255),
                                        bgColor
                                    ]
                                ),
                                center: .topLeading,
                                angle: .degrees(180 + 45)
                            )
                        )
                        .frame(maxWidth: .infinity, maxHeight: .infinity)
                } else {
                    Rectangle()
                        .fill(Color(red: 49/255, green: 49/255, blue: 49/255))
                        .frame(maxWidth: .infinity, maxHeight: .infinity)
                }
                
                
                // 绘制右上角唱片
                ZStack(alignment: .topTrailing) {
                    Image(isWhiteBackground ? "cd_white" : "cd_black")
                        .resizable()
                        .interpolation(.high)
                        .scaledToFit()
                        .frame(width: cdSize, height: cdSize)
                        .clipped()
                        .offset(x: offsetX, y: offsetY)
                    
                    if let image = loadImageFromFile() {
                        Image(uiImage: image)
                            .resizable()
                            .interpolation(.high)
                            .scaledToFit()
                            .frame(width: coverSize, height: coverSize)
                            .clipShape(Circle())
                            .clipped()
                            .offset(x: -coverAndCdDiffSize + offsetX, y: coverAndCdDiffSize + offsetY)
                    }
                    
                    playButton(
                        offsetX: -playButtonAndCdDiffSize + offsetX,
                        offsetY: playButtonAndCdDiffSize + offsetY
                    )
                }
                .contentTransition(.interpolate)
                .animation(.smooth(duration: 0.45), value: entry.isPlaying)
                
                // 绘制左侧一列歌曲信息
                VStack(alignment: .leading) {
                    Image("logo")
                        .resizable()
                        .scaledToFit()
                        .frame(width: 30, height: 30)
                        .clipped()
                        .padding(.bottom, 5)
                    
                    Spacer()
                    
                    Text(playText)
                        .font(.system(size: 10))
                        .bold()
                        .foregroundColor(.gray)
                        .frame(maxWidth: .infinity, alignment: .leading)
                        .padding(.trailing, actionReservedWidth)
                        .padding(.bottom, 3)
                    
                    Text(entry.songName)
                        .font(.system(size: 12))
                        .bold()
                        .foregroundColor(lyricForeground(isPrimary: true))
                        .frame(maxWidth: .infinity, alignment: .leading)
                        .padding(.trailing, actionReservedWidth)
                        .padding(.bottom, 2)
                    
                    Text(entry.songArtist)
                        .font(.system(size: 12, weight: .light))
                        .foregroundColor(.gray)
                        .frame(maxWidth: .infinity, alignment: .leading)
                        .padding(.trailing, actionReservedWidth)
                        
                }
                .padding()
                
                VStack {
                    Spacer()
                    favoriteButton()
                }
            }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
        .widgetURL(shutdownOpenURL)
    }

    /// 关机态点卡片打开 App；用 widgetURL 而不是全屏 Link，避免桌面白卡渲染成鱼骨。
    var shutdownOpenURL: URL? {
        if entry.isShutdown && !entry.isPreview {
            return URL(string: "llmp://")
        }
        return nil
    }

    var familyCanvasSize: CGSize {
        switch entry.widgetFamily {
        case .systemMedium:
            return CGSize(width: 338, height: 158)
        default:
            return CGSize(width: 158, height: 158)
        }
    }

    var actionReservedWidth: CGFloat {
        entry.widgetFamily == .systemMedium ? 110 : 72
    }

    /// 黑卡必须用明确 RGB，系统 `.white` 在 Widget 预览里可能被折成浅色叠在白底上，歌词会消失。
    func lyricForeground(isPrimary: Bool) -> Color {
        if isPrimary {
            return isWhiteBackground
                ? Color(red: 0, green: 0, blue: 0)
                : Color(red: 1, green: 1, blue: 1)
        }
        return Color(red: 0.7, green: 0.7, blue: 0.7, opacity: 0.7)
    }

    func calcCdOffsetX(entry: ExampleEntry, canvas: CGSize) -> CGFloat {
        var offset = 0.0
        switch entry.widgetFamily {
        case .systemSmall:
            offset = (canvas.width - 70) / 2
        case .systemMedium:
            offset = (canvas.width - 152) / 2 + (entry.isPlaying ? 55 : 15)
        default:
            break
        }
        return offset
    }

    func calcCdOffsetY(entry: ExampleEntry, canvas: CGSize) -> CGFloat {
        var offset = 0.0
        switch entry.widgetFamily {
        case .systemSmall:
            offset = (70 - canvas.height) / 2
        case .systemMedium:
            offset = (152 - canvas.height) / 2 - (entry.isPlaying ? 55 : 15)
        default:
            break
        }
        return offset
    }
    
    func calcBgColor(entry: ExampleEntry) -> Color {
        var intColors: [Double] = [230.0, 215.0, 210.0]
        if entry.bgColor.contains(",") {
            intColors = entry.bgColor.components(separatedBy: ",").compactMap(Double.init)
        }
        return Color(
            red: Double(intColors[0]) / 255,
            green: Double(intColors[1]) / 255,
            blue: Double(intColors[2]) / 255
        )
    }
    
    func loadImageFromFile() -> UIImage? {
        // 没歌/关机/添加页预览都不该读 App Group 里的旧 sharedImage
        //（和 Flutter 共用 group，重装后文件还在）。
        if entry.isPreview || entry.isShutdown || entry.songName.isEmpty {
            return nil
        }
        guard let fileURL = FileManager.default.containerURL(
            forSecurityApplicationGroupIdentifier: widgetGroupId
        )?.appendingPathComponent("sharedImage.png") else { return nil }
        return UIImage(contentsOfFile: fileURL.path)
    }
    
    func calcPlayText(entry: ExampleEntry) -> String {
        var playTextArr: [String] = [WidgetI18n.t("playing"), WidgetI18n.t("paused")]
        if entry.playText.contains(",") {
            playTextArr = entry.playText.components(separatedBy: ",")
        }
        return entry.isPlaying ? playTextArr[0] : playTextArr[1]
    }

    @ViewBuilder
    func transportButton(assetName: String, action: String) -> some View {
        let icon = Image(assetName)
            .renderingMode(.template)
            .resizable()
            .scaledToFit()
            .foregroundColor(.white)
            .frame(width: transportIconSize, height: transportIconSize)
            .frame(width: actionButtonSize, height: actionButtonSize)
        if entry.isPreview || entry.isShutdown {
            icon
        } else if #available(iOSApplicationExtension 17, *) {
            Button(
                intent: BackgroundIntent(
                    url: URL(string: "homeWidgetExample://\(action)")
                )
            ) {
                icon
            }
            .buttonStyle(.plain)
        } else {
            icon
        }
    }

    @ViewBuilder
    func playButton(offsetX: CGFloat, offsetY: CGFloat) -> some View {
        let icon = Image(systemName: entry.isPlaying ? "pause.fill" : "play.fill")
            .resizable()
            .scaledToFit()
            .frame(width: 18, height: 18)
            .foregroundColor(.white)
        // 预览和关机态都不能挂 App Intent，否则桌面白卡会掉回 placeholder 鱼骨。
        if entry.isPreview || entry.isShutdown {
            icon
                .padding(8)
                .offset(x: offsetX, y: offsetY)
        } else if #available(iOSApplicationExtension 17, *) {
            Button(intent: BackgroundIntent(url: URL(string: "homeWidgetExample://toggle_play"))) {
                icon
            }
            .buttonStyle(.plain)
            .padding(8)
            .offset(x: offsetX, y: offsetY)
        }
    }

    @ViewBuilder
    func favoriteButton() -> some View {
        HStack(spacing: 8) {
            if entry.widgetFamily == .systemMedium {
                transportButton(
                    assetName: "PlayerPrev",
                    action: "previous"
                )
            }
            transportButton(
                assetName: "PlayerNext",
                action: "next"
            )
            favoriteControl()
        }
        .frame(maxWidth: .infinity, alignment: .bottomTrailing)
        .padding(8)
    }

    @ViewBuilder
    func favoriteControl() -> some View {
        let icon = Image(entry.isFavorite ? "FavoriteClick" : "FavoriteUnClick")
            .resizable()
            .scaledToFit()
            .frame(width: actionButtonSize, height: actionButtonSize)
        if entry.isPreview || entry.isShutdown {
            icon
        } else if #available(iOSApplicationExtension 17, *) {
            Button(intent: BackgroundIntent(url: URL(string: "homeWidgetExample://toggle_love"))) {
                icon
            }
            .buttonStyle(.plain)
        } else {
            icon
        }
    }
}

struct HomeWidgetExampleWhite: Widget {
    let kind = "HomeWidgetExampleWhite"

    var body: some WidgetConfiguration {
        StaticConfiguration(kind: kind, provider: Provider()) { (entry) in
            widgetRoot(entry: entry, isWhiteBackground: true)
        }
            .configurationDisplayName(WidgetI18n.t("widget_white"))
            .contentMarginsDisabled()
            .supportedFamilies([.systemSmall, .systemMedium])
            .description(WidgetI18n.t("widget_desc"))
    }
}

struct HomeWidgetExampleBlack: Widget {
    let kind = "HomeWidgetExampleBlack"

    var body: some WidgetConfiguration {
        StaticConfiguration(kind: kind, provider: Provider()) { (entry) in
            widgetRoot(entry: entry, isWhiteBackground: false)
        }
            .configurationDisplayName(WidgetI18n.t("widget_black"))
            .contentMarginsDisabled()
            .supportedFamilies([.systemSmall, .systemMedium])
            .description(WidgetI18n.t("widget_desc"))
    }
}

@ViewBuilder
private func widgetRoot(entry: ExampleEntry, isWhiteBackground: Bool) -> some View {
    let view = HomeWidgetExampleEntryView(entry: entry, isWhiteBackground: isWhiteBackground)
        .containerBackground(for: .widget) {
            widgetContainerFill(entry: entry, isWhiteBackground: isWhiteBackground)
        }
    if entry.isPreview {
        view.unredacted()
    } else {
        view
    }
}

@ViewBuilder
private func widgetContainerFill(entry: ExampleEntry, isWhiteBackground: Bool) -> some View {
    if isWhiteBackground {
        Color(red: 229/255, green: 233/255, blue: 235/255)
    } else {
        Color(red: 49/255, green: 49/255, blue: 49/255)
    }
}

private func sampleBgColor(_ bgColor: String) -> Color {
    var intColors: [Double] = [230.0, 215.0, 210.0]
    if bgColor.contains(",") {
        intColors = bgColor.components(separatedBy: ",").compactMap(Double.init)
    }
    return Color(
        red: Double(intColors[0]) / 255,
        green: Double(intColors[1]) / 255,
        blue: Double(intColors[2]) / 255
    )
}

/// Widget 扩展未链接 ComposeApp，按系统语言对齐主工程四套文案。
private enum WidgetI18n {
    static func t(_ key: String) -> String {
        let table: [String: String]
        switch Locale.current.language.languageCode?.identifier {
        case "en":
            table = [
                "playing": "Playing",
                "paused": "Paused",
                "widget_white": "LLMP Music Widget (White)",
                "widget_black": "LLMP Music Widget (Black)",
                "widget_desc": "LoveLive! music player",
            ]
        case "ja":
            table = [
                "playing": "放送中",
                "paused": "停止しました",
                "widget_white": "LLMP 音楽ウィジェット (白)",
                "widget_black": "LLMP 音楽ウィジェット (黒)",
                "widget_desc": "LoveLive!メディアプレーヤー",
            ]
        case "de":
            table = [
                "playing": "Wird abgespielt",
                "paused": "Pausiert",
                "widget_white": "LLMP Musik-Widget (Weiß)",
                "widget_black": "LLMP Musik-Widget (Schwarz)",
                "widget_desc": "LoveLive! Musikplayer",
            ]
        default:
            table = [
                "playing": "播放中",
                "paused": "已暂停",
                "widget_white": "LLMP 音乐组件 (白)",
                "widget_black": "LLMP 音乐组件 (黑)",
                "widget_desc": "LoveLive!媒体播放器",
            ]
        }
        return table[key] ?? key
    }
}

#Preview(as: .systemSmall) {
    HomeWidgetExampleWhite()
} timeline: {
    ExampleEntry(
        date: Date(),
        widgetFamily: .systemSmall,
        songName: "Song Name",
        songArtist: "Song Artist",
        isFavorite: true,
        isPlaying: true,
        playText: "playing,paused",
        isShutdown: true,
        bgColor: "255,255,255",
        isPreview: true
    )
}

#Preview(as: .systemMedium) {
    HomeWidgetExampleWhite()
} timeline: {
    sampleEntry(family: .systemMedium, isPreview: true)
}