import Foundation
import AppKit
import IRC

// A secondary window for IRC chat: short vertically, long horizontally.
// Title: "Prole IRC". Positioned below the main Prole Status window.
final class IRCWindowController: NSWindowController {
    private let serverField: NSTextField = {
        let tf = NSTextField(string: "localhost")
        tf.placeholderString = "Server"
        // Approximate 32-character width using a monospaced font
        tf.font = NSFont.monospacedSystemFont(ofSize: NSFont.systemFontSize, weight: .regular)
        tf.translatesAutoresizingMaskIntoConstraints = false
        return tf
    }()
    private let sslCheckbox: NSButton = {
        let cb = NSButton(checkboxWithTitle: "SSL", target: nil, action: nil)
        cb.translatesAutoresizingMaskIntoConstraints = false
        return cb
    }()
    private let connectButton: NSButton = {
        let b = NSButton(title: "#prole", target: nil, action: nil)
        b.bezelStyle = .rounded
        b.translatesAutoresizingMaskIntoConstraints = false
        return b
    }()
    private let portSuffixLabel: NSTextField = {
        let tf = NSTextField(labelWithString: ":6667")
        tf.font = NSFont.monospacedDigitSystemFont(ofSize: NSFont.systemFontSize, weight: .regular)
        tf.textColor = .secondaryLabelColor
        tf.translatesAutoresizingMaskIntoConstraints = false
        return tf
    }()
    private let transcriptView = IRCTranscriptView()

    // Persistence keys
    private let defaults = UserDefaults.standard
    private let kServerKey = "irc.server"
    private let kSSLKey = "irc.ssl"

    private var ircClient: IRCClient?
    private var joinedDefaultChannel = false

    init(initialServer: String? = nil, initialSSL: Bool? = nil) {
        let style: NSWindow.StyleMask = [.titled, .closable, .miniaturizable, .resizable]
        // Start with the same width as the Main (Prole Status) window (720)
        let initialRect = NSRect(x: 0, y: 0, width: 720, height: 300)
        let window = NSWindow(contentRect: initialRect, styleMask: style, backing: .buffered, defer: false)
        super.init(window: window)

        window.isReleasedWhenClosed = false
        window.title = "Prole IRC"
        window.level = .normal
        window.collectionBehavior = [.canJoinAllSpaces]
        window.appearance = NSAppearance(named: .aqua)
        window.minSize = NSSize(width: 480, height: 200)

        // Restore persisted values
        let savedServer = initialServer ?? defaults.string(forKey: kServerKey) ?? "localhost"
        let savedSSL = initialSSL ?? defaults.bool(forKey: kSSLKey)
        serverField.stringValue = savedServer
        sslCheckbox.state = savedSSL ? .on : .off
        updatePortSuffix()

        // Layout
        let content = NSView()
        content.translatesAutoresizingMaskIntoConstraints = false
        window.contentView = content

        let topBar = NSStackView()
        topBar.orientation = .horizontal
        topBar.alignment = .centerY
        topBar.spacing = 8
        topBar.translatesAutoresizingMaskIntoConstraints = false
        content.addSubview(topBar)

        // Make the server field flexible (no fixed minimum). It should stretch to fill available space.
        serverField.setContentHuggingPriority(.defaultLow, for: .horizontal)
        serverField.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
        connectButton.setContentHuggingPriority(.required, for: .horizontal)
        connectButton.setContentCompressionResistancePriority(.required, for: .horizontal)
        sslCheckbox.setContentHuggingPriority(.required, for: .horizontal)
        sslCheckbox.setContentCompressionResistancePriority(.required, for: .horizontal)
        portSuffixLabel.setContentHuggingPriority(.defaultHigh, for: .horizontal)
        portSuffixLabel.setContentCompressionResistancePriority(.defaultHigh, for: .horizontal)

        topBar.addArrangedSubview(NSTextField(labelWithString: "Server:"))
        topBar.addArrangedSubview(serverField)
        topBar.addArrangedSubview(portSuffixLabel)
        topBar.addArrangedSubview(sslCheckbox)
        topBar.addArrangedSubview(connectButton)

        // Transcript fills remainder
        transcriptView.translatesAutoresizingMaskIntoConstraints = false
        content.addSubview(transcriptView)

        let layoutGuide = window.contentLayoutGuide as Any?
        let guide = (layoutGuide as? NSLayoutGuide)
        let topAnchorRef = guide?.topAnchor ?? content.topAnchor
        let leadingAnchorRef = guide?.leadingAnchor ?? content.leadingAnchor
        let trailingAnchorRef = guide?.trailingAnchor ?? content.trailingAnchor
        let bottomAnchorRef = guide?.bottomAnchor ?? content.bottomAnchor

        NSLayoutConstraint.activate([
            topBar.topAnchor.constraint(equalTo: topAnchorRef, constant: 8),
            topBar.leadingAnchor.constraint(equalTo: leadingAnchorRef, constant: 8),
            // Make the top bar span full width so its children (server field) can stretch
            topBar.trailingAnchor.constraint(equalTo: trailingAnchorRef, constant: -8),

            transcriptView.topAnchor.constraint(equalTo: topBar.bottomAnchor, constant: 8),
            transcriptView.leadingAnchor.constraint(equalTo: leadingAnchorRef),
            transcriptView.trailingAnchor.constraint(equalTo: trailingAnchorRef),
            transcriptView.bottomAnchor.constraint(equalTo: bottomAnchorRef)
        ])

        // Wire actions
        sslCheckbox.target = self; sslCheckbox.action = #selector(didToggleSSL)
        connectButton.target = self; connectButton.action = #selector(didTapConnect)

        connectButton.isEnabled = true
        connectButton.toolTip = "Connect to #prole"
    }

    required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") }

    func show() {
        window?.makeKeyAndOrderFront(nil)
        NSApp.activate(ignoringOtherApps: false)
    }
    func hide() { window?.orderOut(nil) }
    var isVisible: Bool { window?.isVisible ?? false }

    // Position this window directly below the reference window, left-aligned.
    func position(below refWindow: NSWindow, gap: CGFloat = 8) {
        guard let this = window else { return }
        let refFrame = refWindow.frame
        var newFrame = this.frame
        // Match width to the reference (Prole Status) window
        newFrame.size.width = refFrame.size.width
        newFrame.origin.x = refFrame.origin.x
        newFrame.origin.y = refFrame.origin.y - newFrame.height - gap
        this.setFrame(newFrame, display: true, animate: false)
    }

    @objc private func didToggleSSL() {
        updatePortSuffix()
    }

    private func updatePortSuffix() {
        let ssl = (sslCheckbox.state == .on)
        portSuffixLabel.stringValue = ssl ? ":6697" : ":6667"
    }

    @objc private func didTapConnect() {
        let ssl = (sslCheckbox.state == .on)
        let raw = serverField.stringValue.trimmingCharacters(in: .whitespacesAndNewlines)
        let host = IRCWindowController.stripPort(from: raw)
        let port = ssl ? 6697 : 6667

        // Persist
        defaults.set(host, forKey: kServerKey)
        defaults.set(ssl, forKey: kSSLKey)

        connectTo(host: host, port: port, ssl: ssl)
    }

    private static func stripPort(from server: String) -> String {
        if let idx = server.lastIndex(of: ":") {
            // Only strip if it looks like host:port and port is digits
            let after = server[server.index(after: idx)...]
            if after.allSatisfy({ $0.isNumber }) {
                return String(server[..<idx])
            }
        }
        return server
    }

    private func nickname() -> String {
        let base = Host.current().localizedName ?? "prole"
        let sanitized = base.replacingOccurrences(of: "[^A-Za-z0-9]", with: "-", options: .regularExpression)
        return "prole-\(sanitized)"
    }

    private func connectTo(host: String, port: Int, ssl: Bool) {
        // Note: TLS/SSL is not yet supported by the swift-nio-irc-client package here.
        if ssl {
            transcriptView.appendLine("Note: SSL/TLS not implemented in current IRC client; attempting plain connection…")
        }
        let nick = nickname()
        let options = IRCClientOptions(
            port: port,
            host: host,
            password: nil,
            nickname: IRCNickName(nick)!,
            userInfo: IRCUserInfo(username: nick, hostname: host, servername: host, realname: "Prole")
        )
        let client = IRCClient(options: options)
        self.ircClient = client
        self.joinedDefaultChannel = false

        // Delegate callbacks
        class Delegate: IRCClientDelegate {
            weak var owner: IRCWindowController?
            init(owner: IRCWindowController) { self.owner = owner }

            func client(_ client: IRCClient, registered nick: IRCNickName, with userInfo: IRCUserInfo) {
                owner?.transcriptView.appendLine("Registered as \(nick.stringValue)")
                // Join default channel
                if owner?.joinedDefaultChannel == false {
                    client.send(.otherCommand("JOIN", ["#prole"]))
                    owner?.joinedDefaultChannel = true
                }
            }
            func clientFailedToRegister(_ client: IRCClient) {
                owner?.transcriptView.appendLine("Failed to register with server")
            }
            func client(_ client: IRCClient, received message: IRCMessage) {
                // Render a few common messages
                switch message.command {
                case .PRIVMSG(let target, let text):
                    // The upstream message model may not expose a prefix property consistently across versions.
                    // Fallback to unknown sender for now.
                    let from = "?"
                    if case .channel(let ch) = target.first {
                        owner?.transcriptView.appendLine("[\(ch)] <\(from)> \(text)")
                    } else {
                        owner?.transcriptView.appendLine("<\(from)> \(text)")
                    }
                case .NOTICE(_, let text):
                    owner?.transcriptView.appendLine("-notice- \(text)")
                default:
                    break
                }
            }
            func client(_ client: IRCClient, messageOfTheDay: String) {
                owner?.transcriptView.appendLine("-motd- \(messageOfTheDay)")
            }
            func client(_ client: IRCClient, notice message: String, for recipients: [IRCMessageRecipient]) {
                owner?.transcriptView.appendLine("-notice- \(message)")
            }
            func client(_ client: IRCClient, message: String, from user: IRCUserID, for recipients: [IRCMessageRecipient]) {
                let who = user.nick.stringValue
                owner?.transcriptView.appendLine("<\(who)> \(message)")
            }
            func client(_ client: IRCClient, changedUserModeTo mode: IRCUserMode) {}
            func client(_ client: IRCClient, changedNickTo nick: IRCNickName) {
                owner?.transcriptView.appendLine("You are now known as \(nick.stringValue)")
            }
            func client(_ client: IRCClient, user: IRCUserID, joined: [IRCChannelName]) {
                let who = user.nick.stringValue
                let channels = joined.map { $0.stringValue }.joined(separator: ", ")
                owner?.transcriptView.appendLine("-- \(who) joined \(channels)")
            }
            func client(_ client: IRCClient, user: IRCUserID, left: [IRCChannelName], with: String?) {
                let who = user.nick.stringValue
                let channels = left.map { $0.stringValue }.joined(separator: ", ")
                owner?.transcriptView.appendLine("-- \(who) left \(channels)")
            }
            func client(_ client: IRCClient, changeTopic: String, of channel: IRCChannelName) {
                owner?.transcriptView.appendLine("-- topic for \(channel.stringValue): \(changeTopic)")
            }
        }

        client.delegate = Delegate(owner: self)
        transcriptView.appendLine("Connecting to \(host):\(port)…")
        client.connect()
    }
}

// A simple scrollable transcript view that fills its container
final class IRCTranscriptView: NSView {
    private let scroll = NSScrollView()
    private let textView = NSTextView()

    override init(frame frameRect: NSRect) {
        super.init(frame: frameRect)
        translatesAutoresizingMaskIntoConstraints = false

        scroll.translatesAutoresizingMaskIntoConstraints = false
        scroll.hasVerticalScroller = true
        scroll.hasHorizontalScroller = false
        scroll.borderType = .bezelBorder

        textView.isEditable = false
        textView.isSelectable = true
        textView.font = NSFont.monospacedSystemFont(ofSize: 12, weight: .regular)
        textView.textContainerInset = NSSize(width: 6, height: 6)
        scroll.documentView = textView

        addSubview(scroll)
        NSLayoutConstraint.activate([
            scroll.topAnchor.constraint(equalTo: topAnchor),
            scroll.leadingAnchor.constraint(equalTo: leadingAnchor),
            scroll.trailingAnchor.constraint(equalTo: trailingAnchor),
            scroll.bottomAnchor.constraint(equalTo: bottomAnchor)
        ])
    }

    required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") }

    convenience init() {
        self.init(frame: .zero)
    }

    func appendLine(_ line: String) {
        let ts = IRCTranscriptView.timestamp()
        let s = "[\(ts)] \(line)\n"
        if let storage = textView.textStorage {
            storage.append(NSAttributedString(string: s))
        } else {
            textView.string.append(s)
        }
        textView.scrollToEndOfDocument(nil)
    }

    private static func timestamp() -> String {
        let df = DateFormatter()
        df.locale = .current
        df.timeZone = .current
        df.dateFormat = "HH:mm:ss"
        return df.string(from: Date())
    }
}