import AppKit
import Carbon
import Foundation
import WebKit

struct Manifest: Decodable {
    let baseUrl: String
    let statusUrl: String
    let openAgentUrl: String
    let profiles: [Profile]
    let hotkeys: [Hotkey]
}

struct Profile: Decodable {
    let name: String
    let toggleShortcut: String
}

struct Hotkey: Decodable {
    let shortcut: String
    let endpoint: String
}

struct RecordingStatus: Decodable {
    let isRecording: Bool
    let state: String
    let launchProfile: String?
}

@main
final class DesktopControls: NSObject, NSApplicationDelegate, NSMenuDelegate {
    private let manifest: Manifest
    private var status = RecordingStatus(isRecording: false, state: "Idle", launchProfile: nil)
    private var statusItem: NSStatusItem!
    private var registeredHotkeys: [UInt32: Hotkey] = [:]
    private var timer: Timer?
    private var agentWindow: NSWindow?

    override init() {
        guard CommandLine.arguments.count == 2,
              let data = try? Data(contentsOf: URL(fileURLWithPath: CommandLine.arguments[1])),
              let decoded = try? JSONDecoder().decode(Manifest.self, from: data) else {
            fputs("Usage: macos-desktop-controls <manifest.json>\n", stderr)
            exit(2)
        }
        manifest = decoded
        super.init()
    }

    static func main() {
        let application = NSApplication.shared
        let delegate = DesktopControls()
        application.delegate = delegate
        application.setActivationPolicy(.accessory)
        application.run()
    }

    func applicationDidFinishLaunching(_ notification: Notification) {
        statusItem = NSStatusBar.system.statusItem(withLength: NSStatusItem.squareLength)
        statusItem.button?.image = NSImage(
            systemSymbolName: "waveform.circle",
            accessibilityDescription: "Meeting Assistant")
        let menu = NSMenu()
        menu.delegate = self
        statusItem.menu = menu
        registerHotkeys()
        refreshStatus()
        timer = Timer.scheduledTimer(withTimeInterval: 2, repeats: true) { [weak self] _ in
            self?.refreshStatus()
        }
    }

    func applicationWillTerminate(_ notification: Notification) {
        timer?.invalidate()
    }

    func menuWillOpen(_ menu: NSMenu) {
        rebuildMenu(menu)
        refreshStatus()
    }

    private func rebuildMenu(_ menu: NSMenu) {
        menu.removeAllItems()
        let stateItem = NSMenuItem(title: tooltip, action: nil, keyEquivalent: "")
        stateItem.isEnabled = false
        menu.addItem(stateItem)
        menu.addItem(.separator())
        menu.addItem(item("Open agent", #selector(openAgent)))

        if status.isRecording {
            menu.addItem(item("Stop meeting recording and transcribe", #selector(stopRecording)))
            menu.addItem(item("Cancel meeting recording and discard", #selector(abortRecording)))
        } else {
            for (index, profile) in manifest.profiles.enumerated() {
                let entry = item(
                    "Start meeting recording (\(profile.name))",
                    #selector(startProfile(_:)))
                entry.tag = index
                entry.keyEquivalent = menuKey(from: profile.toggleShortcut)
                entry.keyEquivalentModifierMask = menuModifiers(from: profile.toggleShortcut)
                menu.addItem(entry)
            }
        }
        menu.addItem(.separator())
        menu.addItem(item("Exit", #selector(exitApplication)))
    }

    private var tooltip: String {
        if status.isRecording {
            return status.launchProfile.map { "Meeting Assistant — recording (\($0))" }
                ?? "Meeting Assistant — recording"
        }
        return status.state.lowercased() == "summarizing"
            ? "Meeting Assistant — summarizing"
            : "Meeting Assistant — idle"
    }

    private func item(_ title: String, _ action: Selector) -> NSMenuItem {
        let result = NSMenuItem(title: title, action: action, keyEquivalent: "")
        result.target = self
        return result
    }

    @objc private func openAgent() {
        if agentWindow == nil {
            let webView = WKWebView(frame: .zero)
            let window = NSWindow(
                contentRect: NSRect(x: 0, y: 0, width: 840, height: 760),
                styleMask: [.titled, .closable, .miniaturizable, .resizable],
                backing: .buffered,
                defer: false)
            window.title = "Meeting Summary Agent"
            window.contentView = webView
            window.center()
            window.isReleasedWhenClosed = false
            webView.load(URLRequest(url: URL(string: manifest.openAgentUrl)!))
            agentWindow = window
        }
        NSApplication.shared.activate(ignoringOtherApps: true)
        agentWindow?.makeKeyAndOrderFront(nil)
    }

    @objc private func startProfile(_ sender: NSMenuItem) {
        let profile = manifest.profiles[sender.tag]
        post(path: "/profiles/\(escaped(profile.name))/recording/start")
    }

    @objc private func stopRecording() {
        post(path: "/recording/stop")
    }

    @objc private func abortRecording() {
        post(path: "/recording/abort")
    }

    @objc private func exitApplication() {
        post(path: "/application/exit")
        DispatchQueue.main.asyncAfter(deadline: .now() + 0.3) {
            NSApplication.shared.terminate(nil)
        }
    }

    private func refreshStatus() {
        guard let url = URL(string: manifest.statusUrl) else { return }
        URLSession.shared.dataTask(with: url) { [weak self] data, _, _ in
            guard let data,
                  let next = try? JSONDecoder().decode(RecordingStatus.self, from: data) else { return }
            DispatchQueue.main.async {
                self?.status = next
                self?.statusItem.button?.image = NSImage(
                    systemSymbolName: next.isRecording ? "record.circle.fill" : "waveform.circle",
                    accessibilityDescription: self?.tooltip)
            }
        }.resume()
    }

    private func post(path: String) {
        post(url: manifest.baseUrl + path)
    }

    private func post(url value: String) {
        guard let url = URL(string: value) else { return }
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
        URLSession.shared.dataTask(with: request) { [weak self] _, _, _ in
            DispatchQueue.main.asyncAfter(deadline: .now() + 0.2) {
                self?.refreshStatus()
            }
        }.resume()
    }

    private func registerHotkeys() {
        var eventType = EventTypeSpec(
            eventClass: OSType(kEventClassKeyboard),
            eventKind: OSType(kEventHotKeyPressed))
        InstallEventHandler(
            GetApplicationEventTarget(),
            { _, event, context in
                guard let event, let context else { return noErr }
                var identifier = EventHotKeyID()
                GetEventParameter(
                    event,
                    EventParamName(kEventParamDirectObject),
                    EventParamType(typeEventHotKeyID),
                    nil,
                    MemoryLayout<EventHotKeyID>.size,
                    nil,
                    &identifier)
                let owner = Unmanaged<DesktopControls>.fromOpaque(context).takeUnretainedValue()
                if let hotkey = owner.registeredHotkeys[identifier.id] {
                    owner.post(path: hotkey.endpoint)
                }
                return noErr
            },
            1,
            &eventType,
            Unmanaged.passUnretained(self).toOpaque(),
            nil)

        for (index, hotkey) in manifest.hotkeys.enumerated() {
            guard let keyCode = carbonKeyCode(from: hotkey.shortcut) else { continue }
            let identifier = EventHotKeyID(signature: fourCC("MTGA"), id: UInt32(index + 1))
            var reference: EventHotKeyRef?
            let result = RegisterEventHotKey(
                keyCode,
                carbonModifiers(from: hotkey.shortcut),
                identifier,
                GetApplicationEventTarget(),
                0,
                &reference)
            if result == noErr {
                registeredHotkeys[identifier.id] = hotkey
            }
        }
    }

    private func escaped(_ value: String) -> String {
        value.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? value
    }
}

private func tokens(_ shortcut: String) -> [String] {
    shortcut.uppercased().split(separator: "+").map(String.init)
}

private func carbonModifiers(from shortcut: String) -> UInt32 {
    let parts = tokens(shortcut)
    var result: UInt32 = 0
    if parts.contains("CTRL") || parts.contains("CONTROL") { result |= UInt32(controlKey) }
    if parts.contains("ALT") || parts.contains("OPTION") { result |= UInt32(optionKey) }
    if parts.contains("SHIFT") { result |= UInt32(shiftKey) }
    if parts.contains("WIN") || parts.contains("WINDOWS") || parts.contains("CMD") || parts.contains("COMMAND") {
        result |= UInt32(cmdKey)
    }
    return result
}

private func menuModifiers(from shortcut: String) -> NSEvent.ModifierFlags {
    let parts = tokens(shortcut)
    var result: NSEvent.ModifierFlags = []
    if parts.contains("CTRL") || parts.contains("CONTROL") { result.insert(.control) }
    if parts.contains("ALT") || parts.contains("OPTION") { result.insert(.option) }
    if parts.contains("SHIFT") { result.insert(.shift) }
    if parts.contains("WIN") || parts.contains("WINDOWS") || parts.contains("CMD") || parts.contains("COMMAND") {
        result.insert(.command)
    }
    return result
}

private func menuKey(from shortcut: String) -> String {
    tokens(shortcut).last?.lowercased() ?? ""
}

private func carbonKeyCode(from shortcut: String) -> UInt32? {
    guard let key = tokens(shortcut).last, key.count == 1, let scalar = key.unicodeScalars.first else {
        return nil
    }
    let codes: [Character: UInt32] = [
        "A": 0, "S": 1, "D": 2, "F": 3, "H": 4, "G": 5, "Z": 6, "X": 7,
        "C": 8, "V": 9, "B": 11, "Q": 12, "W": 13, "E": 14, "R": 15,
        "Y": 16, "T": 17, "M": 46, "L": 37, "N": 45, "P": 35, "O": 31,
        "I": 34, "U": 32, "J": 38, "K": 40
    ]
    return codes[Character(String(scalar))]
}

private func fourCC(_ value: String) -> OSType {
    value.utf8.reduce(0) { ($0 << 8) + OSType($1) }
}