//
//  DocuframeView.swift
//  GasTankAR
//
//  Created by Dennis Nemec on 28.08.26.
//

import SwiftUI
import SwiftData

/// DOCUframe-Tab: Auswahl aufgenommener Fotos und Übergabe an DOCUframe (Upload) bzw. Mailversand.
struct DocuframeView: View {
    let project: Project

    @State private var viewModel = DocuframeViewModel()

    private let columns = [GridItem(.adaptive(minimum: 110), spacing: 2)]

    private var photos: [ProjectPhoto] {
        project.photos.sorted { $0.creationDate > $1.creationDate }
    }

    var body: some View {
        Group {
            if photos.isEmpty {
                ContentUnavailableView(
                    "Keine Fotos",
                    systemImage: "photo.on.rectangle.angled",
                    description: Text("Nimm im AR-Modus Fotos auf, um sie an DOCUframe zu übergeben.")
                )
            } else {
                ScrollView {
                    LazyVGrid(columns: columns, spacing: 2) {
                        ForEach(photos) { photo in
                            selectableThumbnail(photo)
                        }
                    }
                    .padding(2)
                }
            }
        }
        .safeAreaInset(edge: .bottom) {
            if !photos.isEmpty { actionBar }
        }
        .alert(
            viewModel.result?.title ?? "",
            isPresented: resultBinding,
            presenting: viewModel.result
        ) { _ in
            Button("OK", role: .cancel) {}
        } message: { result in
            Text(result.message)
        }
    }

    private func selectableThumbnail(_ photo: ProjectPhoto) -> some View {
        let selected = viewModel.isSelected(photo)
        return PhotoThumbnail(imageData: photo.imageData)
            .aspectRatio(1, contentMode: .fit)
            .clipped()
            .overlay(alignment: .topTrailing) {
                Image(systemName: selected ? "checkmark.circle.fill" : "circle")
                    .font(.title3)
                    .symbolRenderingMode(.palette)
                    .foregroundStyle(.white, selected ? Color.accentColor : Color.black.opacity(0.35))
                    .padding(6)
                    .shadow(radius: 2)
            }
            .overlay {
                if selected {
                    Rectangle().strokeBorder(Color.accentColor, lineWidth: 3)
                }
            }
            .contentShape(.rect)
            .onTapGesture { viewModel.toggleSelection(photo) }
    }

    private var actionBar: some View {
        VStack(spacing: 10) {
            Text(viewModel.hasSelection ? "\(viewModel.selectionCount) ausgewählt" : "Fotos zum Übertragen auswählen")
                .font(.footnote)
                .foregroundStyle(.secondary)

            VStack(spacing: 8) {
                Button {
                    Task { await viewModel.upload(from: photos, leadID: project.leadID) }
                } label: {
                    Label("In DOCUframe hochladen", systemImage: "arrow.up.doc")
                        .frame(maxWidth: .infinity)
                }
                .buttonStyle(.borderedProminent)

                Button {
                    Task { await viewModel.sendEmail(from: photos, leadID: project.leadID) }
                } label: {
                    Label("E-Mail senden", systemImage: "envelope")
                        .frame(maxWidth: .infinity)
                }
                .buttonStyle(.bordered)
            }
            .controlSize(.large)
            .disabled(!viewModel.hasSelection || viewModel.isProcessing)

            if viewModel.isProcessing {
                ProgressView()
            }
        }
        .padding()
        .background(.bar)
    }

    private var resultBinding: Binding<Bool> {
        Binding(
            get: { viewModel.result != nil },
            set: { if !$0 { viewModel.result = nil } }
        )
    }
}

#Preview {
    let sample = PreviewSupport.galleryProjectContainer()
    return NavigationStack {
        DocuframeView(project: sample.project)
    }
    .modelContainer(sample.container)
}