import AppKit

@MainActor
final class TranslationSettingsController: NSViewController {
    private let keyField = NSSecureTextField()
    private let status = NSTextField(wrappingLabelWithString: "")
    private var statusIsError = false
    private var themeObservation: ThemeObservation?
    private let credentials: TranslationController.Credentials

    init(credentials: TranslationController.Credentials = .keychain) {
        self.credentials = credentials
        super.init(nibName: nil, bundle: nil)
    }

    required init?(coder: NSCoder) { fatalError("Conjure creates Translate settings programmatically") }

    override func loadView() {
        view = NSView()
        keyField.placeholderString = "OpenAI API key (saved in Keychain)"
        keyField.setAccessibilityLabel("OpenAI API key")
        let save = NSButton(title: "Save Key", target: self, action: #selector(saveKey))
        let forget = NSButton(title: "Forget Key", target: self, action: #selector(forgetKey))
        for button in [save, forget] {
            button.bezelStyle = .rounded
            button.contentTintColor = ThemePalette.accent
        }
        let controls = NSStackView(views: [keyField, save, forget])
        controls.orientation = .horizontal
        controls.alignment = .centerY
        controls.spacing = 8
        keyField.setContentHuggingPriority(.defaultLow, for: .horizontal)
        keyField.widthAnchor.constraint(greaterThanOrEqualToConstant: 220).isActive = true
        status.setAccessibilityLabel("Translation credential status and errors")
        let myMemory = NSTextField(wrappingLabelWithString:
            "MyMemory · No key · 500 bytes/request · 5,000 characters/day. Text is sent to MyMemory only when you translate; avoid sensitive content."
        )
        let openAI = NSTextField(wrappingLabelWithString:
            "OpenAI · gpt-6-luna · Text and optional situation/context are sent to OpenAI only when you explicitly translate, not when advancing to context. Saving a key does not send your text. Your API key is stored in Keychain."
        )
        for label in [status, myMemory, openAI] {
            label.textColor = ThemePalette.secondaryText
        }
        let stack = NSStackView(views: [controls, status, myMemory, openAI])
        stack.orientation = .vertical
        stack.alignment = .leading
        stack.spacing = 12
        stack.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(stack)
        NSLayoutConstraint.activate([
            stack.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            stack.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            stack.topAnchor.constraint(equalTo: view.topAnchor),
            stack.bottomAnchor.constraint(equalTo: view.bottomAnchor),
            controls.widthAnchor.constraint(equalTo: stack.widthAnchor),
        ])
        for label in [status, myMemory, openAI] {
            label.widthAnchor.constraint(equalTo: stack.widthAnchor).isActive = true
        }
        themeObservation = ThemeObservation { [weak self] in
            save.contentTintColor = ThemePalette.accent
            forget.contentTintColor = ThemePalette.accent
            myMemory.textColor = ThemePalette.secondaryText
            openAI.textColor = ThemePalette.secondaryText
            guard let self else { return }
            self.status.textColor = self.statusIsError ? ThemePalette.error : ThemePalette.secondaryText
        }
        do {
            setStatus(try credentials.load() == nil ? "No OpenAI API key saved." : "OpenAI API key saved in Keychain.")
        } catch { setStatus(error.localizedDescription, isError: true) }
    }

    @objc private func saveKey() {
        let key = keyField.stringValue.trimmingCharacters(in: .whitespacesAndNewlines)
        guard !key.isEmpty, !key.contains(where: { $0.isNewline }) else {
            setStatus("Enter a valid API key before saving.", isError: true)
            return
        }
        do {
            try credentials.save(key)
            keyField.stringValue = ""
            setStatus("API key saved in Keychain.")
            NotificationCenter.default.post(name: Notification.Name("ConjureTranslationCredentialsChanged"), object: self)
        } catch { setStatus(error.localizedDescription, isError: true) }
    }

    @objc private func forgetKey() {
        do {
            try credentials.forget()
            keyField.stringValue = ""
            setStatus("API key removed.")
            NotificationCenter.default.post(name: Notification.Name("ConjureTranslationCredentialsChanged"), object: self)
        } catch { setStatus(error.localizedDescription, isError: true) }
    }

    private func setStatus(_ message: String, isError: Bool = false) {
        statusIsError = isError
        status.stringValue = message
        status.textColor = isError ? ThemePalette.error : ThemePalette.secondaryText
    }
}