import AppKit
import VoiceCatCore

// PrivateMessageWindowController — a modeless window for a single private message
// conversation, owned and routed-to by MainWindowController. Mirrors the Windows client's
// `PrivateMessageForm` (clients/windows/VoiceCat.App/Forms/PrivateMessageForm.cs): each PM
// conversation opens in its own window instead of sharing the main chat log via a scope
// dropdown. MainWindowController routes incoming `.textMessage` events with `.private` scope
// to the right window; outgoing PMs are echoed back by the server and arrive through the
// same path (no optimistic local echo).
//
// The window is modeless (`NSWindow`) rather than a sheet because the user should be able to
// keep chatting in the main channel while a PM window is open — the same Discord/Slack
// pattern the Windows client follows.

final class PrivateMessageWindowController: NSWindowController, NSWindowDelegate, NSTextViewDelegate {

    // MARK: - Owned state

    private let client: VoiceCatClient
    let otherUserId: UInt32
    private let selfUserId: UInt32
    private let nickname: String

    // MARK: - UI

    private let historyTextView: NSTextView = {
        let tv = NSTextView()
        tv.isEditable = false
        tv.isSelectable = true
        tv.isAutomaticQuoteSubstitutionEnabled = false
        tv.textContainerInset = NSSize(width: 4, height: 4)
        return tv
    }()

    private let composeField = NSTextField()
    private let sendButton = NSButton()

    // MARK: - Init

    init(client: VoiceCatClient, otherUserId: UInt32, nickname: String, selfUserId: UInt32) {
        self.client = client
        self.otherUserId = otherUserId
        self.selfUserId = selfUserId
        self.nickname = nickname

        let window = NSWindow(
            contentRect: NSRect(x: 0, y: 0, width: 460, height: 360),
            styleMask: [.titled, .closable, .miniaturizable, .resizable],
            backing: .buffered,
            defer: false
        )
        window.title = "Private Message — \(nickname)"
        window.minSize = NSSize(width: 300, height: 220)
        window.center()
        super.init(window: window)
        window.delegate = self

        buildUI()
    }

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

    // MARK: - UI construction

    private func buildUI() {
        guard let contentView = window?.contentView else { return }

        historyTextView.setAccessibilityLabel("Private message history with \(nickname)")

        let scroll = NSScrollView()
        scroll.documentView = historyTextView
        scroll.hasVerticalScroller = true
        scroll.borderType = .noBorder
        scroll.translatesAutoresizingMaskIntoConstraints = false
        contentView.addSubview(scroll)

        composeField.placeholderString = "Type a private message…"
        composeField.setAccessibilityLabel("Private message to \(nickname)")
        composeField.target = self
        composeField.action = #selector(sendClicked)

        sendButton.title = "Send"
        sendButton.bezelStyle = .rounded
        sendButton.target = self
        sendButton.action = #selector(sendClicked)
        sendButton.setAccessibilityLabel("Send private message")
        sendButton.keyEquivalent = "\r"

        let sep = NSBox()
        sep.boxType = .separator
        sep.translatesAutoresizingMaskIntoConstraints = false
        contentView.addSubview(sep)

        let composeBar = NSStackView(views: [composeField, sendButton])
        composeBar.orientation = .horizontal
        composeBar.spacing = 6
        composeBar.translatesAutoresizingMaskIntoConstraints = false
        contentView.addSubview(composeBar)

        NSLayoutConstraint.activate([
            scroll.topAnchor.constraint(equalTo: contentView.topAnchor),
            scroll.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
            scroll.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
            scroll.bottomAnchor.constraint(equalTo: sep.topAnchor),

            sep.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
            sep.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
            sep.heightAnchor.constraint(equalToConstant: 1),
            sep.bottomAnchor.constraint(equalTo: composeBar.topAnchor),

            composeBar.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 8),
            composeBar.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -8),
            composeBar.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: -8),
            composeBar.heightAnchor.constraint(equalToConstant: 28),

            sendButton.widthAnchor.constraint(equalToConstant: 70),
        ])

        window?.makeFirstResponder(composeField)
    }

    // MARK: - Public — called by MainWindowController

    /// Append a message line. `isSelf=true` renders in gray (our own echoed outgoing message);
    /// `false` renders in default color (incoming from the other user). Mirrors the Windows
    /// `PrivateMessageForm.AppendMessage`.
    func appendMessage(time: String, isSelf: Bool, sender: String, text: String) {
        let line = "[\(time)] \(sender): \(text)\n"
        let attrs: [NSAttributedString.Key: Any] = isSelf
            ? [.foregroundColor: NSColor.secondaryLabelColor]
            : [:]
        let attributed = NSAttributedString(string: line, attributes: attrs)
        historyTextView.textStorage?.append(attributed)
        historyTextView.scrollToEndOfDocument(nil)
    }

    /// Append a gray status/activity line (e.g. the other user disconnected). Mirrors the
    /// Windows `PrivateMessageForm.AppendActivity`.
    func appendActivity(_ text: String) {
        let time = DateFormatter.localizedString(from: Date(), dateStyle: .none, timeStyle: .short)
        let line = "[\(time)] \(text)\n"
        let attributed = NSAttributedString(string: line, attributes: [
            .foregroundColor: NSColor.secondaryLabelColor,
        ])
        historyTextView.textStorage?.append(attributed)
        historyTextView.scrollToEndOfDocument(nil)
    }

    // MARK: - Send

    @objc private func sendClicked() {
        let msg = composeField.stringValue.trimmingCharacters(in: .whitespaces)
        guard !msg.isEmpty else { return }
        client.sendText(scope: .private, targetId: otherUserId, text: msg)
        composeField.stringValue = ""
    }

    // MARK: - NSWindowDelegate

    func windowWillClose(_ notification: Notification) {
        // Notify the owner so it can drop this controller from its pmWindows map.
        // MainWindowController observes NSWindow.willCloseNotification on this window.
    }
}