import AppKit

final class AddServerSheet: NSViewController {

    var onComplete: ((SavedServer?) -> Void)?

    private var editing: SavedServer?

    private let hostField = NSTextField()
    private let portField: NSTextField = {
        let f = NSTextField()
        f.stringValue = "7878"
        return f
    }()
    private let authPicker = NSPopUpButton()
    private let nicknameField = NSTextField()
    private let usernameField = NSTextField()
    private let passwordField = NSSecureTextField()
    private let savePwCheckbox = NSButton(checkboxWithTitle: "Save password in Keychain", target: nil, action: nil)

    init(editing: SavedServer?) {
        self.editing = editing
        super.init(nibName: nil, bundle: nil)
    }

    required init?(coder: NSCoder) { fatalError() }

    override func loadView() {
        view = NSView(frame: NSRect(x: 0, y: 0, width: 380, height: 260))
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        buildUI()
        if let s = editing {
            hostField.stringValue = s.host
            portField.stringValue = "\(s.port)"
            authPicker.selectItem(withTitle: s.authMode == .guest ? "Guest" : "Account")
            nicknameField.stringValue = s.nickname ?? ""
            usernameField.stringValue = s.savedUsername ?? ""
            updateAuthVisibility()
        }
    }

    private func buildUI() {
        let title = NSTextField(labelWithString: editing == nil ? "Add Server" : "Edit Server")
        title.font = .boldSystemFont(ofSize: 14)

        let hostLabel = NSTextField(labelWithString: "Host:")
        let portLabel = NSTextField(labelWithString: "Port:")
        let authLabel = NSTextField(labelWithString: "Auth:")
        let nickLabel = NSTextField(labelWithString: "Nickname:")
        let userLabel = NSTextField(labelWithString: "Username:")
        let pwLabel = NSTextField(labelWithString: "Password:")

        hostField.placeholderString = "hostname or IP"
        hostField.setAccessibilityLabel("Server hostname or IP address")

        portField.setAccessibilityLabel("Server port")

        authPicker.addItem(withTitle: "Guest")
        authPicker.addItem(withTitle: "Account")
        authPicker.target = self; authPicker.action = #selector(authChanged)
        authPicker.setAccessibilityLabel("Authentication mode")

        nicknameField.placeholderString = "leave blank to use your system name"
        nicknameField.setAccessibilityLabel("Guest nickname (display name)")

        usernameField.placeholderString = "username"
        usernameField.setAccessibilityLabel("Username")

        passwordField.placeholderString = "leave blank to enter at connect"
        passwordField.setAccessibilityLabel("Password (optional — enter at connect time if blank)")

        savePwCheckbox.setAccessibilityLabel("Save password in system Keychain")

        let cancelButton = NSButton(title: "Cancel", target: self, action: #selector(cancelClicked))
        cancelButton.bezelStyle = .rounded
        let saveButton = NSButton(title: "Save", target: self, action: #selector(saveClicked))
        saveButton.bezelStyle = .rounded
        saveButton.keyEquivalent = "\r"
        saveButton.setAccessibilityLabel("Save server")

        let grid = NSGridView(views: [
            [hostLabel, hostField],
            [portLabel, portField],
            [authLabel, authPicker],
            [nickLabel, nicknameField],
            [userLabel, usernameField],
            [pwLabel, passwordField],
            [NSView(), savePwCheckbox],
        ])
        grid.rowSpacing = 8
        grid.columnSpacing = 8
        grid.column(at: 0).xPlacement = .trailing

        let buttonRow = NSStackView(views: [NSView(), cancelButton, saveButton])
        buttonRow.orientation = .horizontal; buttonRow.spacing = 8

        let stack = NSStackView(views: [title, grid, buttonRow])
        stack.orientation = .vertical
        stack.spacing = 16
        stack.edgeInsets = NSEdgeInsets(top: 20, left: 20, bottom: 20, right: 20)
        stack.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(stack)
        NSLayoutConstraint.activate([
            stack.topAnchor.constraint(equalTo: view.topAnchor),
            stack.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            stack.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            stack.bottomAnchor.constraint(equalTo: view.bottomAnchor),
        ])

        updateAuthVisibility()
    }

    @objc private func authChanged() { updateAuthVisibility() }

    private func updateAuthVisibility() {
        let isAccount = authPicker.titleOfSelectedItem == "Account"
        nicknameField.isEnabled = !isAccount
        usernameField.isEnabled = isAccount
        passwordField.isEnabled = isAccount
        savePwCheckbox.isEnabled = isAccount
    }

    @objc private func saveClicked() {
        let host = hostField.stringValue.trimmingCharacters(in: .whitespaces)
        guard !host.isEmpty else {
            hostField.becomeFirstResponder(); return
        }
        let portStr = portField.stringValue.trimmingCharacters(in: .whitespaces)
        guard let port = UInt16(portStr), port > 0 else {
            portField.becomeFirstResponder(); return
        }
        let isGuest = authPicker.titleOfSelectedItem == "Guest"
        var server = editing ?? SavedServer(host: host, port: port,
                                            authMode: isGuest ? .guest : .password)
        server.host = host; server.port = port
        server.authMode = isGuest ? .guest : .password
        server.savedUsername = isGuest ? nil : usernameField.stringValue.trimmingCharacters(in: .whitespaces)
        let nick = nicknameField.stringValue.trimmingCharacters(in: .whitespaces)
        server.nickname = nick.isEmpty ? nil : nick

        if !isGuest && savePwCheckbox.state == .on {
            let pw = passwordField.stringValue
            if !pw.isEmpty {
                let tag = server.keychainTag ?? "voicecat.server.\(server.id.uuidString)"
                server.keychainTag = tag
                ServerListStore.savePassword(pw, tag: tag)
            }
        } else if isGuest {
            if let tag = server.keychainTag { ServerListStore.deletePassword(tag: tag) }
            server.keychainTag = nil
        }

        dismiss(nil)
        onComplete?(server)
    }

    @objc private func cancelClicked() {
        dismiss(nil)
        onComplete?(nil)
    }
}