import AppKit
import SwiftUI

/// Guia "Modelos" — replica a UI de gerenciamento de modelos do Hex:
/// cards curados com badge "Recomendado", estrelas de precisão/velocidade,
/// estado Instalado/Em uso, barra de progresso de download, e ações
/// Download / Selecionar / Mostrar no Finder / Remover.
struct ModelDownloadView: View {
    @State private var catalog: Catalog?
    @State private var downloading: String?
    @State private var progress: Double = 0
    @State private var isLoading = false
    @State private var errorMessage: String?
    @State private var modelsDirText: String = ""
    @State private var hfTokenText: String = ""
    @State private var numSpeakersText: String = ""
    @State private var language: String = "auto"

    private let languages: [(String, String)] = [
        ("auto", "Detectar automaticamente"),
        ("pt", "Português"),
        ("en", "Inglês"),
        ("es", "Espanhol"),
        ("fr", "Francês"),
        ("de", "Alemão"),
        ("it", "Italiano"),
        ("nl", "Holandês"),
        ("ja", "Japonês"),
        ("ko", "Coreano"),
        ("zh", "Chinês"),
    ]

    var body: some View {
        Form {
            storageSection
            diarizationSection
            if let errorMessage {
                Section {
                    Label(errorMessage, systemImage: "exclamationmark.triangle.fill")
                        .foregroundStyle(.red)
                }
            }
            Section {
                if isLoading {
                    ProgressView().controlSize(.small)
                        .frame(maxWidth: .infinity, alignment: .center)
                } else if let catalog {
                    if catalog.installedCount == 0 {
                        noModelChooser(catalog)
                    }
                    ForEach(catalog.orderedModels) { model in
                        modelRow(model)
                    }
                }
            } header: {
                Text("Modelos de Transcrição")
            } footer: {
                Label("Os modelos rodam localmente nesta máquina. Downloads ficam na pasta configurada acima.",
                      systemImage: "lock.shield")
                    .font(.caption)
                    .foregroundStyle(.secondary)
            }
            if catalog?.installedCount ?? 0 > 0 {
                languageSection
            }
        }
        .formStyle(.grouped)
        .task { await refresh() }
    }

    // MARK: - Transcription language

    /// Idiooma padrão usado em todas as transcrições do programa. Aparece abaixo
    /// do modelo escolhido, conforme o modelo selecionado na aba Modelos.
    private var languageSection: some View {
        Section {
            Picker("Idioma", selection: $language) {
                ForEach(languages, id: \.0) { code, label in
                    Text(label).tag(code)
                }
            }
        } header: {
            Text("Idioma de Transcrição")
        } footer: {
            Text("Usado em todas as transcrições do programa. Escolha conforme o modelo selecionado acima.")
                .font(.caption)
                .foregroundStyle(.secondary)
        }
        .onChange(of: language) { _, newValue in
            saveLanguage(newValue)
        }
    }

    private func saveLanguage(_ code: String) {
        PythonBridge.call(command: "set_language", arguments: ["language": code]) { _, _ in }
    }

    // MARK: - Diarization

    private var diarizationSection: some View {
        Section {
            VStack(alignment: .leading, spacing: 10) {
                if let msg = catalog?.diarizationMessage, !msg.isEmpty {
                    Label(msg, systemImage: catalog?.diarization == true ? "checkmark.circle" : "exclamationmark.triangle")
                        .font(.caption)
                        .foregroundStyle(catalog?.diarization == true ? Color.secondary : Color.orange)
                }
                SecureField("Token HuggingFace (diarização)", text: $hfTokenText)
                    .textFieldStyle(.roundedBorder)
                    .help("Token com acesso aos modelos gated pyannote (segmentation + speaker-diarization)")
                HStack {
                    TextField("Nº de participantes (vazio = automático)", text: $numSpeakersText)
                        .textFieldStyle(.roundedBorder)
                    Button("Salvar") { saveDiarization() }
                        .disabled(isLoading)
                }
            }
        } header: {
            Text("Diarização (participantes)")
        } footer: {
            Text("Opcional. Sem token, cada fala é atribuída a um único participante padrão.")
                .font(.caption)
                .foregroundStyle(.secondary)
        }
    }

    private func saveDiarization() {
        var args: [String: Any] = ["num_speakers": numSpeakersText]
        if !hfTokenText.isEmpty {
            args["token"] = hfTokenText
        }
        PythonBridge.call(command: "set_diarization", arguments: args) { result, _ in
            DispatchQueue.main.async {
                hfTokenText = ""
                numSpeakersText = result?["num_speakers"] as? String ?? numSpeakersText
                Task { await refresh() }
            }
        }
    }

    // MARK: - Storage

    private var storageSection: some View {
        Section("Local de Armazenamento") {
            VStack(alignment: .leading, spacing: 8) {
                HStack(spacing: 8) {
                    TextField("Pasta de modelos", text: $modelsDirText)
                        .textFieldStyle(.roundedBorder)
                        .disabled(true)
                    Button {
                        pickAndSaveFolder()
                    } label: {
                        Image(systemName: "folder")
                    }
                    .help("Selecionar pasta de modelos e salvar")
                }
            }
        }
    }

    /// Present an NSOpenPanel to choose a folder, then save it and refresh the
    /// installed-model list so newly scanned downloads appear immediately.
    private func pickAndSaveFolder() {
        let panel = NSOpenPanel()
        panel.canChooseDirectories = true
        panel.canChooseFiles = false
        panel.allowsMultipleSelection = false
        panel.prompt = "Selecionar"
        panel.message = "Escolha a pasta onde os modelos serão salvos"
        if let current = URL(string: modelsDirText), FileManager.default.fileExists(atPath: current.path) {
            panel.directoryURL = current
        }
        if panel.runModal() == .OK, let url = panel.url {
            modelsDirText = url.path
            saveDir()
        }
    }

    // MARK: - No model chooser (first run)

    private func noModelChooser(_ catalog: Catalog) -> some View {
        let recommended = catalog.orderedModels.filter { $0.isRecommended }
        return VStack(alignment: .leading, spacing: 10) {
            HStack(spacing: 12) {
                Image(systemName: "arrow.down.circle.fill")
                    .font(.title3)
                    .foregroundStyle(.tint)
                VStack(alignment: .leading, spacing: 3) {
                    Text("Escolha um modelo de transcrição")
                        .font(.body.weight(.medium))
                    Text("Baixe um modelo local para começar a transcrever.")
                        .font(.caption).foregroundStyle(.secondary)
                }
            }
            if !recommended.isEmpty {
                HStack(spacing: 10) {
                    ForEach(recommended) { model in
                        noModelCard(model)
                    }
                }
            }
        }
        .padding(10)
        .background(Color(nsColor: .controlBackgroundColor),
                    in: RoundedRectangle(cornerRadius: 8))
    }

    private func noModelCard(_ model: ModelInfo) -> some View {
        Button {
            startDownload(model)
        } label: {
            VStack(alignment: .leading, spacing: 8) {
                HStack(alignment: .top, spacing: 8) {
                    Text(model.displayName).font(.body.weight(.medium))
                    Spacer(minLength: 8)
                    Text("Recomendado")
                        .font(.caption2.weight(.medium))
                        .foregroundStyle(.tint)
                        .padding(.horizontal, 6).padding(.vertical, 2)
                        .background(Color.accentColor.opacity(0.12), in: Capsule())
                }
                HStack(spacing: 6) {
                    Text(model.language)
                    Text("·")
                    Text(model.storage)
                    Spacer()
                    Image(systemName: "arrow.down.circle")
                }
                .font(.caption).foregroundStyle(.secondary)
            }
            .padding(12)
            .frame(maxWidth: .infinity, alignment: .leading)
            .background(Color(nsColor: .windowBackgroundColor).opacity(0.45),
                        in: RoundedRectangle(cornerRadius: 8))
            .overlay(RoundedRectangle(cornerRadius: 8).stroke(Color.accentColor.opacity(0.4), lineWidth: 1))
        }
        .buttonStyle(.plain)
    }

    // MARK: - Model row

    private func modelRow(_ model: ModelInfo) -> some View {
        let isThisDownloading = downloading == model.internalName
        return HStack(spacing: 0) {
            VStack(alignment: .leading, spacing: 4) {
                HStack(spacing: 7) {
                    Text(model.displayName).font(.body.weight(.medium))
                    if model.isRecommended && !model.isDownloaded {
                        badge("Recomendado", color: .blue)
                    }
                    if model.isDownloaded {
                        badge("Instalado", color: .green)
                    }
                    if model.isSelected {
                        badge("Em uso", color: .purple)
                    }
                }
                HStack(spacing: 10) {
                    Text(model.language).font(.caption).foregroundStyle(.secondary)
                    rating("Precisão", filled: model.accuracy)
                    rating("Velocidade", filled: model.speed)
                    Spacer()
                    Text(model.storage).font(.caption).foregroundStyle(.secondary)
                }
            }
            .frame(maxWidth: .infinity, alignment: .leading)

            trailingControls(for: model, isDownloading: isThisDownloading)
        }
        .padding(.vertical, 6)
    }

    private func rating(_ label: String, filled: Int) -> some View {
        HStack(spacing: 4) {
            Text(label).font(.caption2).foregroundStyle(.secondary)
            HStack(spacing: 3) {
                ForEach(0..<5, id: \.self) { i in
                    Image(systemName: i < filled ? "circle.fill" : "circle")
                        .font(.system(size: 7))
                        .foregroundColor(i < filled ? .blue : .gray.opacity(0.5))
                }
            }
        }
    }

    private func badge(_ text: String, color: Color) -> some View {
        Text(text)
            .font(.caption2.weight(.medium))
            .foregroundStyle(color)
            .padding(.horizontal, 6).padding(.vertical, 2)
            .background(color.opacity(0.12), in: Capsule())
    }

    @ViewBuilder
    private func trailingControls(for model: ModelInfo, isDownloading: Bool) -> some View {
        if isDownloading {
            HStack(spacing: 8) {
                ProgressView(value: progress).progressViewStyle(.linear).frame(width: 120)
                Text("\(Int(progress * 100))%").font(.caption).monospacedDigit().foregroundStyle(.secondary)
                Button("Cancelar", role: .destructive) { cancelDownload(model) }
                    .controlSize(.small)
            }
        } else if model.isDownloaded {
            if model.isSelected {
                Label("Em uso", systemImage: "checkmark.circle.fill")
                    .foregroundStyle(.green).font(.callout)
            } else {
                Button("Selecionar") { select(model) }
                    .buttonStyle(.borderedProminent).controlSize(.small)
            }
            Menu {
                Button { openInFinder(model) } label: {
                    Label("Mostrar no Finder", systemImage: "folder")
                }
                Divider()
                Button(role: .destructive) { delete(model) } label: {
                    Label("Remover Download…", systemImage: "trash")
                }
            } label: {
                Image(systemName: "ellipsis.circle").foregroundStyle(.secondary)
            }
            .menuStyle(.borderlessButton).fixedSize()
        } else {
            Button("Download") { startDownload(model) }
                .buttonStyle(.borderedProminent).controlSize(.small)
        }
    }

    // MARK: - Actions

    private func refresh() async {
        isLoading = true
        errorMessage = nil
        PythonBridge.call(command: "catalog") { result, err in
            DispatchQueue.main.async {
                isLoading = false
                if let result {
                    catalog = Catalog(json: result)
                    modelsDirText = catalog?.modelsDir ?? ""
                    downloading = nil
                    progress = 0
                    numSpeakersText = catalog?.numSpeakers ?? ""
                    language = catalog?.language ?? "auto"
                } else {
                    errorMessage = err ?? "Falha ao carregar modelos."
                }
            }
        }
    }

    private func startDownload(_ model: ModelInfo) {
        downloading = model.internalName
        progress = 0
        PythonBridge.run(command: "download", arguments: ["model": model.internalName]) { obj in
            DispatchQueue.main.async {
                if let f = obj["fraction"] as? NSNumber { progress = f.doubleValue }
                if obj["type"] as? String == "error" {
                    errorMessage = obj["message"] as? String
                }
            }
        } completion: { _, _ in
            DispatchQueue.main.async { Task { await refresh() } }
        }
    }

    private func cancelDownload(_ model: ModelInfo) {
        PythonBridge.call(command: "cancel", arguments: ["model": model.internalName]) { _, _ in }
    }

    private func select(_ model: ModelInfo) {
        PythonBridge.call(command: "select", arguments: ["model": model.internalName]) { _, _ in
            DispatchQueue.main.async { Task { await refresh() } }
        }
    }

    private func delete(_ model: ModelInfo) {
        PythonBridge.call(command: "delete", arguments: ["model": model.internalName]) { _, _ in
            DispatchQueue.main.async { Task { await refresh() } }
        }
    }

    private func openInFinder(_ model: ModelInfo) {
        PythonBridge.call(command: "open_finder", arguments: ["model": model.internalName]) { _, _ in }
    }

    private func saveDir() {
        let path = modelsDirText.trimmingCharacters(in: .whitespacesAndNewlines)
        guard !path.isEmpty else { return }
        PythonBridge.call(command: "set_models_dir", arguments: ["dir": path]) { result, _ in
            DispatchQueue.main.async {
                if let result, result["ok"] as? Bool == true {
                    self.catalog?.modelsDir = result["models_dir"] as? String ?? ""
                    self.modelsDirText = result["models_dir"] as? String ?? path
                    Task { await refresh() }
                }
            }
        }
    }
}