import SwiftUI
import UniformTypeIdentifiers

/// 1:1 ImageOptim layout: a two-column table (File | Savings) filling the
/// window, a thin grey header, and a bottom status bar with file count, an
/// overall savings percentage, and a settings gear. No inline controls.
struct ContentView: View {
    @EnvironmentObject var model: AppModel

    var body: some View {
        VStack(spacing: 0) {
            if !model.encoderReady {
                Text("\(model.format.encoder.cmd) not found — run: brew install \(model.format.encoder.brew)")
                    .foregroundColor(.white).frame(maxWidth: .infinity)
                    .padding(6).background(Color.red)
            }
            header
            Divider()
            table
            Divider()
            statusBar
        }
        .background(Color(NSColor.controlBackgroundColor))
    }

    private var header: some View {
        HStack(spacing: 0) {
            Text("File").padding(.leading, 28)
            Spacer()
            Text("Savings").padding(.trailing, 16)
        }
        .font(.system(size: 11, weight: .semibold))
        .foregroundColor(.secondary)
        .frame(height: 22)
        .background(Color(NSColor.windowBackgroundColor))
    }

    private var table: some View {
        ZStack {
            if model.items.isEmpty {
                VStack(spacing: 8) {
                    Image(systemName: "photo.on.rectangle.angled")
                        .font(.system(size: 40)).foregroundColor(.secondary)
                    Text("Drop images here").font(.title3).foregroundColor(.secondary)
                    Text("JPG · PNG · GIF → JPEG XL").font(.caption).foregroundColor(.secondary)
                }
            } else {
                List(model.items) { ImageRow(item: $0) }
                    .listStyle(.plain)
            }
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
        .onDrop(of: [UTType.fileURL], isTargeted: nil) { providers in
            for p in providers {
                _ = p.loadObject(ofClass: URL.self) { url, _ in
                    if let url { DispatchQueue.main.async { model.add(urls: [url]) } }
                }
            }
            return true
        }
    }

    private var statusBar: some View {
        HStack(spacing: 12) {
            Button(action: openPanel) { Image(systemName: "plus") }
                .buttonStyle(.borderless).help("Add files or a folder")
            SettingsGear().environmentObject(model)
            Text("\(model.items.count) files").foregroundColor(.secondary)
            if model.busy { ProgressView().scaleEffect(0.5) }
            Spacer()
            Text("saved").foregroundColor(.secondary)
            Text(String(format: "%.1f%%", model.overallSavedPercent))
                .foregroundColor(.green).bold().monospacedDigit()
        }
        .font(.system(size: 12))
        .padding(.horizontal, 12).frame(height: 34)
        .background(Color(NSColor.windowBackgroundColor))
    }

    /// "+" → pick files and/or folders; folders recurse via AppModel.add.
    private func openPanel() {
        let panel = NSOpenPanel()
        panel.canChooseFiles = true
        panel.canChooseDirectories = true
        panel.allowsMultipleSelection = true
        if panel.runModal() == .OK { model.add(urls: panel.urls) }
    }
}

/// Gear button → popover with the quality/effort/lossless settings ImageOptim
/// keeps in Preferences.
struct SettingsGear: View {
    @EnvironmentObject var model: AppModel
    @State private var open = false
    var body: some View {
        Button { open.toggle() } label: { Image(systemName: "gearshape") }
            .buttonStyle(.borderless)
            .popover(isPresented: $open) {
                VStack(alignment: .leading, spacing: 12) {
                    Picker("Format", selection: $model.format) {
                        ForEach(Compressor.Format.allCases) { Text($0.label).tag($0) }
                    }.pickerStyle(.segmented)
                    Toggle("Lossless", isOn: $model.lossless)
                    if !model.lossless {
                        HStack { Text("Quality"); Slider(value: $model.distance, in: 0.5...3.0)
                            Text(String(format: "d%.1f", model.distance)).monospacedDigit() }
                    }
                    Stepper("Effort \(model.effort)", value: $model.effort, in: 1...9)
                    Toggle("Keep original", isOn: $model.keepOriginal)
                }.padding(16).frame(width: 240)
            }
    }
}

struct ImageRow: View {
    @ObservedObject var item: ImageItem
    var body: some View {
        HStack(spacing: 8) {
            if let t = item.thumb {
                Image(nsImage: t).resizable().frame(width: 22, height: 22).cornerRadius(3)
            } else {
                Image(systemName: "photo").frame(width: 22, height: 22).foregroundColor(.secondary)
            }
            icon.frame(width: 14)
            Text(item.url.lastPathComponent).lineLimit(1)
            Spacer()
            Group {
                switch item.status {
                case .done: Text(String(format: "%.1f%%", item.savedFraction * 100))
                        .foregroundColor(.green).bold()
                case .failed: Text("error").foregroundColor(.red).help(item.message)
                case .skipped: Text("—").foregroundColor(.secondary)
                case .working: ProgressView().scaleEffect(0.5)
                case .pending: Text("…").foregroundColor(.secondary)
                }
            }.monospacedDigit()
        }
        .font(.system(size: 13))
        .padding(.vertical, 2)
        .contentShape(Rectangle())
        .onTapGesture(count: 2) {
            if let out = item.outputURL { NSWorkspace.shared.activateFileViewerSelecting([out]) }
        }
        .onTapGesture(count: 1) { QuickLook.shared.preview(item.url) }
        .contextMenu {
            if let out = item.outputURL {
                Button("Reveal in Finder") { NSWorkspace.shared.activateFileViewerSelecting([out]) }
                if out.pathExtension == "jxl" {
                    Button("Decode back to PNG (compare)") {
                        DispatchQueue.global().async {
                            if let png = try? Compressor.decode(out) {
                                DispatchQueue.main.async { NSWorkspace.shared.activateFileViewerSelecting([png]) }
                            }
                        }
                    }
                }
            }
        }
    }
    @ViewBuilder var icon: some View {
        switch item.status {
        case .done: Image(systemName: "checkmark.circle.fill").foregroundColor(.green)
        case .failed: Image(systemName: "xmark.circle.fill").foregroundColor(.red)
        default: Image(systemName: "photo")
        }
    }
}