/**
 * Pi Notify Extension
 *
 * Sends a native terminal notification when Pi agent is done and waiting for input.
 * Supports multiple terminal protocols:
 * - OSC 777: Ghostty, WezTerm, rxvt-unicode, Windows Terminal 1.26+
 * - OSC 9: iTerm2
 * - OSC 99: Kitty
 * - tmux passthrough wrapper for OSC notifications
 * - Optional sound hook via PI_NOTIFY_SOUND_CMD
 */

import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";

function wrapForTmux(sequence: string): string {
    if (!process.env.TMUX) return sequence;

    // tmux passthrough: wrap in DCS and escape inner ESC bytes.
    const escaped = sequence.split("\x1b").join("\x1b\x1b");
    return `\x1bPtmux;${escaped}\x1b\\`;
}

function notifyOSC777(title: string, body: string): void {
    const sequence = `\x1b]777;notify;${title};${body}\x07`;
    process.stdout.write(wrapForTmux(sequence));
}

function notifyOSC9(message: string): void {
    const sequence = `\x1b]9;${message}\x07`;
    process.stdout.write(wrapForTmux(sequence));
}

function notifyOSC99(title: string, body: string): void {
    // Kitty OSC 99: i=notification id, d=0 means not done yet, p=body for second part
    const titleSequence = `\x1b]99;i=1:d=0;${title}\x1b\\`;
    const bodySequence = `\x1b]99;i=1:p=body;${body}\x1b\\`;
    process.stdout.write(wrapForTmux(titleSequence));
    process.stdout.write(wrapForTmux(bodySequence));
}

function runSoundHook(): void {
    const command = process.env.PI_NOTIFY_SOUND_CMD?.trim();
    if (!command) return;

    try {
        const { spawn } = require("node:child_process");
        const child = spawn(command, {
            shell: true,
            detached: true,
            stdio: "ignore",
        });
        child.unref();
    } catch {
        // Ignore hook errors to avoid breaking notifications
    }
}

function notify(title: string, body: string): void {
    const isIterm2 = process.env.TERM_PROGRAM === "iTerm.app" || Boolean(process.env.ITERM_SESSION_ID);

    if (process.env.WT_SESSION) {
        notifyOSC777(title, body);
    } else if (process.env.KITTY_WINDOW_ID) {
        notifyOSC99(title, body);
    } else if (isIterm2) {
        notifyOSC9(`${title}: ${body}`);
    } else {
        notifyOSC777(title, body);
    }

    runSoundHook();
}

export default function (pi: ExtensionAPI) {
    pi.on("agent_end", async () => {
        notify("Pi", "Ready for input");
    });
}