import SwiftUI
import UniformTypeIdentifiers

struct ContentView: View {
    @EnvironmentObject var model: AppModel

    var body: some View {
        VStack(spacing: 0) {
            if !model.encoderReady {
                banner("cjxl not found — run: brew install jpeg-xl", color: .red)
            }
            controls
            Divider()
            dropZone
            Divider()
            footer
        }
    }

    private var controls: some View {
        HStack(spacing: 16) {
            Toggle("Lossless", isOn: $model.lossless)
            if !model.lossless {
                HStack {
                    Text("Quality")
                    Slider(value: $model.distance, in: 0.5...3.0)
                        .frame(width: 120)
                    Text(String(format: "d%.1f", model.distance)).monospacedDigit()
                }
            }
            Stepper("Effort \(model.effort)", value: $model.effort, in: 1...9)
            Toggle("Keep original", isOn: $model.keepOriginal)
            Spacer()
        }.padding(10)
    }

    private var dropZone: some View {
        ZStack {
            if model.items.isEmpty {
                VStack(spacing: 6) {
                    Image(systemName: "square.and.arrow.down").font(.system(size: 34))
                    Text("Drop JPG / PNG / GIF here").foregroundColor(.secondary)
                }
            } else {
                List(model.items) { ImageRow(item: $0) }
            }
        }
        .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 footer: some View {
        HStack {
            if model.busy { ProgressView().scaleEffect(0.6); Text("Compressing…") }
            Spacer()
            Text("Saved \(human(model.totalSaved))").bold()
        }.padding(8)
    }

    private func banner(_ s: String, color: Color) -> some View {
        Text(s).foregroundColor(.white).frame(maxWidth: .infinity)
            .padding(6).background(color)
    }
}

struct ImageRow: View {
    @ObservedObject var item: ImageItem
    var body: some View {
        HStack {
            icon
            Text(item.url.lastPathComponent).lineLimit(1)
            Spacer()
            switch item.status {
            case .done:
                Text("\(human(item.originalBytes)) → \(human(item.newBytes))").foregroundColor(.secondary)
                Text(String(format: "−%.0f%%", item.savedFraction * 100)).foregroundColor(.green).bold()
            case .failed: Text(item.message).foregroundColor(.red).lineLimit(1)
            case .skipped: Text("no gain").foregroundColor(.secondary)
            case .working: ProgressView().scaleEffect(0.5)
            case .pending: Text("queued").foregroundColor(.secondary)
            }
        }.monospacedDigit()
    }
    @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")
        }
    }
}