import SwiftUI
import PhotosUI

/// 帮助与反馈:内容 + 联系方式 + 可选截图(≤3 张,压缩后上传)。
struct FeedbackView: View {
    @Environment(\.dismiss) private var dismiss
    @State private var content = ""
    @State private var contact = ""
    @State private var pickedItems: [PhotosPickerItem] = []
    @State private var imageDatas: [Data] = []
    @State private var submitting = false
    @State private var toast: String?
    private let service = FeedbackService()

    var body: some View {
        Form {
            Section("反馈内容") {
                TextField("说说你遇到的问题或建议…", text: $content, axis: .vertical)
                    .lineLimit(4...8)
            }
            Section("联系方式(选填)") {
                TextField("手机号 / 微信,方便我们联系你", text: $contact)
            }
            Section("截图(选填)") {
                PhotosPicker(selection: $pickedItems, maxSelectionCount: 3, matching: .images) {
                    Label("添加截图", systemImage: "photo.on.rectangle")
                }
                if !imageDatas.isEmpty {
                    Text("已选 \(imageDatas.count) 张").font(.caption).foregroundStyle(.secondary)
                }
            }
            Section {
                Button {
                    Task { await submit() }
                } label: {
                    Text(submitting ? "提交中…" : "提交反馈").frame(maxWidth: .infinity)
                }
                .disabled(submitting || content.isEmpty)
            }
        }
        .navigationTitle("帮助与反馈")
        .navigationBarTitleDisplayMode(.inline)
        .onChange(of: pickedItems) { _, items in
            Task { await loadImages(items) }
        }
        .overlay(alignment: .bottom) { toastView }
    }

    @ViewBuilder private var toastView: some View {
        if let toast {
            Text(toast)
                .font(.subheadline)
                .padding(.horizontal, 16).padding(.vertical, 10)
                .background(.black.opacity(0.8)).foregroundStyle(.white)
                .clipShape(Capsule()).padding(.bottom, 30)
                .task(id: toast) {
                    try? await Task.sleep(for: .milliseconds(1500))
                    if toast.contains("成功") { dismiss() } else { self.toast = nil }
                }
        }
    }

    private func loadImages(_ items: [PhotosPickerItem]) async {
        var datas: [Data] = []
        for item in items {
            if let raw = try? await item.loadTransferable(type: Data.self),
               let jpeg = ImageDownsampler.jpeg(raw) {
                datas.append(jpeg)
            }
        }
        imageDatas = datas
    }

    private func submit() async {
        submitting = true
        defer { submitting = false }
        do {
            _ = try await service.submit(content: content, contact: contact, images: imageDatas)
            toast = "提交成功,感谢反馈"
        } catch {
            toast = (error as? LocalizedError)?.errorDescription ?? "提交失败,请重试"
        }
    }
}