// postmouse.c — post synthesized mouse events to a specific macOS process.
//
// Build:
//   clang -framework CoreFoundation -framework CoreGraphics \
//     -o scripts/postmouse scripts/postmouse.c
//
// Usage:
//   ./scripts/postmouse <pid> <action> <x> <y> [cmd]
//   <action> move | down | drag | up     (kCGEventMouseMoved / LeftMouseDown /
//                                        LeftMouseDragged / LeftMouseUp)
//   <x> <y>  global display coordinates (CGEventGetLocation space)
//   [cmd]    pass "cmd" to hold the Command modifier (pane-drag gesture)
//
// The press carries the command modifier; drag/up continue the gesture with
// the button already down. CGEventPostToPid is the only injection channel
// that works on a locked macOS console (system-wide posting is dropped when
// loginwindow is frontmost).
#include <CoreFoundation/CoreFoundation.h>
#include <CoreGraphics/CoreGraphics.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

int main(int argc, char **argv) {
    if (argc < 5) {
        fprintf(stderr,
                "usage: postmouse <pid> <move|down|drag|up|scroll> <x> <y> [delta|cmd]\n");
        return 2;
    }
    pid_t pid = (pid_t)atoi(argv[1]);
    const char *action = argv[2];
    double x = atof(argv[3]);
    double y = atof(argv[4]);
    bool withCmd = argc > 5 && strstr(argv[5], "cmd") != NULL;

    // Scroll wheel: <x> <y> are atof-ignored; [delta] is the wheel
    // delta (positive scrolls up/back). CGEventPostToPid delivers it to
    // the frontmost process's wheel handler.
    if (strcmp(action, "scroll") == 0) {
        double delta = (argc > 5) ? atof(argv[5]) : 3.0;
        if (delta == 0.0) delta = 3.0;
        CGEventRef ev = CGEventCreateScrollWheelEvent(NULL,
                                                      kCGScrollEventUnitLine,
                                                      1,
                                                      (int32_t)delta);
        CGEventSetLocation(ev, CGPointMake(x, y));
        CGEventPostToPid(pid, ev);
        CFRelease(ev);
        return 0;
    }

    CGEventType type;
    if (strcmp(action, "move") == 0) type = kCGEventMouseMoved;
    else if (strcmp(action, "down") == 0) type = kCGEventLeftMouseDown;
    else if (strcmp(action, "drag") == 0) type = kCGEventLeftMouseDragged;
    else if (strcmp(action, "up") == 0) type = kCGEventLeftMouseUp;
    else {
        fprintf(stderr, "unknown action: %s\n", action);
        return 2;
    }

    CGEventRef ev = CGEventCreateMouseEvent(NULL, type,
                                            CGPointMake(x, y),
                                            kCGMouseButtonLeft);
    if (withCmd) {
        CGEventSetFlags(ev, kCGEventFlagMaskCommand);
    }
    CGEventPostToPid(pid, ev);
    CFRelease(ev);
    return 0;
}