import AppKit
import SwiftTerm
import Combine

/// Wraps a single SwiftTerm TerminalView + LocalProcess pair.
@MainActor
class TerminalSession: NSObject, ObservableObject, LocalProcessDelegate, TerminalViewDelegate {

    let id = UUID()
    let terminalView: TerminalView
    private var process: LocalProcess?

    @Published var title: String = "shell"
    @Published var isRunning: Bool = true
    @Published var currentDirectory: String?

    init(fontSize: CGFloat) {
        terminalView = TerminalView(frame: NSRect(x: 0, y: 0, width: 600, height: 300))
        super.init()

        terminalView.terminalDelegate = self

        // Solid black — matches every other element in the notch.
        // The single `.opacity(notchOpacity)` on ContentView makes
        // everything uniformly transparent.
        terminalView.nativeBackgroundColor = .black
        terminalView.nativeForegroundColor = .init(white: 0.9, alpha: 1.0)

        let font = NSFont.monospacedSystemFont(ofSize: fontSize, weight: .regular)
        terminalView.font = font

        startShell()
    }

    // MARK: - Shell management

    private func startShell() {
        let shellPath = resolveShell()
        let shellName = (shellPath as NSString).lastPathComponent
        let loginExecName = "-\(shellName)"

        FileManager.default.changeCurrentDirectoryPath(NSHomeDirectory())
        let proc = LocalProcess(delegate: self)
        // Launch as a login shell so user startup files initialize PATH/tools.
        proc.startProcess(
            executable: shellPath,
            args: ["-l"],
            environment: nil,
            execName: loginExecName
        )
        process = proc
        title = shellName
    }

    private func resolveShell() -> String {
        let custom = UserDefaults.standard.string(forKey: NotchSettings.Keys.terminalShell) ?? ""
        if !custom.isEmpty && FileManager.default.isExecutableFile(atPath: custom) {
            return custom
        }
        return ProcessInfo.processInfo.environment["SHELL"] ?? "/bin/zsh"
    }

    func updateFontSize(_ size: CGFloat) {
        terminalView.font = NSFont.monospacedSystemFont(ofSize: size, weight: .regular)
    }

    func terminate() {
        process?.terminate()
        process = nil
        isRunning = false
    }

    // MARK: - LocalProcessDelegate

    nonisolated func processTerminated(_ source: LocalProcess, exitCode: Int32?) {
        Task { @MainActor in self.isRunning = false }
    }

    nonisolated func dataReceived(slice: ArraySlice<UInt8>) {
        let data = slice
        Task { @MainActor in self.terminalView.feed(byteArray: data) }
    }

    nonisolated func getWindowSize() -> winsize {
        var ws = winsize()
        ws.ws_col = 80
        ws.ws_row = 24
        return ws
    }

    // MARK: - TerminalViewDelegate

    func send(source: TerminalView, data: ArraySlice<UInt8>) {
        process?.send(data: data)
    }

    func setTerminalTitle(source: TerminalView, title: String) {
        self.title = title.isEmpty ? "shell" : title
    }

    func sizeChanged(source: TerminalView, newCols: Int, newRows: Int) {
        guard newCols > 0, newRows > 0 else { return }
        guard let proc = process else { return }
        let fd = proc.childfd
        guard fd >= 0 else { return }

        var ws = winsize()
        ws.ws_col = UInt16(newCols)
        ws.ws_row = UInt16(newRows)
        _ = ioctl(fd, TIOCSWINSZ, &ws)
    }

    func hostCurrentDirectoryUpdate(source: TerminalView, directory: String?) {
        currentDirectory = directory
    }

    func scrolled(source: TerminalView, position: Double) {}
    func rangeChanged(source: TerminalView, startY: Int, endY: Int) {}

    func clipboardCopy(source: TerminalView, content: Data) {
        NSPasteboard.general.clearContents()
        NSPasteboard.general.setData(content, forType: .string)
    }

    func requestOpenLink(source: TerminalView, link: String, params: [String : String]) {
        if let url = URL(string: link) { NSWorkspace.shared.open(url) }
    }

    func bell(source: TerminalView) { NSSound.beep() }
    func iTermContent(source: TerminalView, content: ArraySlice<UInt8>) {}
}