SubMiner/src/window-trackers/x11-tracker.ts

/*
  SubMiner - All-in-one sentence mining overlay
  Copyright (C) 2024 sudacode

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

import { execSync } from "child_process";
import { BaseWindowTracker } from "./base-tracker";

export class X11WindowTracker extends BaseWindowTracker {
  private pollInterval: ReturnType<typeof setInterval> | null = null;
  private readonly targetMpvSocketPath: string | null;

  constructor(targetMpvSocketPath?: string) {
    super();
    this.targetMpvSocketPath = targetMpvSocketPath?.trim() || null;
  }

  start(): void {
    this.pollInterval = setInterval(() => this.pollGeometry(), 250);
    this.pollGeometry();
  }

  stop(): void {
    if (this.pollInterval) {
      clearInterval(this.pollInterval);
      this.pollInterval = null;
    }
  }

  private pollGeometry(): void {
    try {
      const windowIds = execSync("xdotool search --class mpv", {
        encoding: "utf-8",
      }).trim();

      if (!windowIds) {
        this.updateGeometry(null);
        return;
      }

      const windowIdList = windowIds.split(/\s+/).filter(Boolean);
      if (windowIdList.length === 0) {
        this.updateGeometry(null);
        return;
      }

      const windowId = this.findTargetWindowId(windowIdList);
      if (!windowId) {
        this.updateGeometry(null);
        return;
      }

      const winInfo = execSync(`xwininfo -id ${windowId}`, {
        encoding: "utf-8",
      });

      const xMatch = winInfo.match(/Absolute upper-left X:\s*(\d+)/);
      const yMatch = winInfo.match(/Absolute upper-left Y:\s*(\d+)/);
      const widthMatch = winInfo.match(/Width:\s*(\d+)/);
      const heightMatch = winInfo.match(/Height:\s*(\d+)/);

      if (xMatch && yMatch && widthMatch && heightMatch) {
        this.updateGeometry({
          x: parseInt(xMatch[1], 10),
          y: parseInt(yMatch[1], 10),
          width: parseInt(widthMatch[1], 10),
          height: parseInt(heightMatch[1], 10),
        });
      } else {
        this.updateGeometry(null);
      }
    } catch (err) {
      this.updateGeometry(null);
    }
  }

  private findTargetWindowId(windowIds: string[]): string | null {
    if (!this.targetMpvSocketPath) {
      return windowIds[0] ?? null;
    }

    for (const windowId of windowIds) {
      if (this.isWindowForTargetSocket(windowId)) {
        return windowId;
      }
    }

    return null;
  }

  private isWindowForTargetSocket(windowId: string): boolean {
    const pid = this.getWindowPid(windowId);
    if (pid === null) {
      return false;
    }

    const commandLine = this.getWindowCommandLine(pid);
    if (!commandLine) {
      return false;
    }

    return (
      commandLine.includes(`--input-ipc-server=${this.targetMpvSocketPath}`) ||
      commandLine.includes(`--input-ipc-server ${this.targetMpvSocketPath}`)
    );
  }

  private getWindowPid(windowId: string): number | null {
    const windowPid = execSync(`xprop -id ${windowId} _NET_WM_PID`, {
      encoding: "utf-8",
    });
    const pidMatch = windowPid.match(/= (\d+)/);
    if (!pidMatch) {
      return null;
    }

    const pid = Number.parseInt(pidMatch[1], 10);
    return Number.isInteger(pid) ? pid : null;
  }

  private getWindowCommandLine(pid: number): string | null {
    const commandLine = execSync(`ps -p ${pid} -o args=`, {
      encoding: "utf-8",
    }).trim();
    return commandLine || null;
  }
}