#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>

#include "raylib.h"
#include "rlgl.h"

void draw_frame(int frame)
{
    BeginDrawing();
    {
        ClearBackground(BEIGE);
        DrawText(TextFormat("frame: %d", frame), 0, 0, 50, RED);
        DrawRectangle(frame*3, frame*2, 50, 50, BLUE);
    }
    EndDrawing();
}

int main()
{
    int pipefd[2];
    pid_t pid;

    if (pipe(pipefd) == -1) {
        printf("ERR: pipe\n");
        return -1;
    }

    pid = fork();
    if (pid == -1) {
        printf("ERR: fork\n");
        return -1;
    }

    if (pid == 0) {
        close(pipefd[1]);

        dup2(pipefd[0], STDIN_FILENO);
        close(pipefd[0]);

        execlp("ffmpeg", "ffmpeg",
               "-y",
               "-f", "rawvideo",
               "-pix_fmt", "rgba",
               "-s", "900x600",
               "-r", "60",
               "-i", "-",
               "output.mp4",
               NULL);

        // unreachable if ffmpeg launch
        printf("ERR: execlp");
        return -1;
    } else {
        close(pipefd[0]);

        InitWindow(900, 600, "screen record test");
        // NOTE: lower FPS if frame bug
        SetTargetFPS(60);
        Vector2 scale = GetWindowScaleDPI();
        int width = GetScreenWidth();
        int height = GetScreenHeight();

        int frame;
        for (frame = 0; frame < 300; frame++) {
            draw_frame(frame);

            int w = width*scale.x;
            int h = height*scale.y;

            unsigned char *screen_data = rlReadScreenPixels(w, h);
            write(pipefd[1], screen_data, w*h*4*sizeof(*screen_data));

            RL_FREE(screen_data);
        }

        close(pipefd[1]);
        wait(NULL);

        printf("%d frame in %.02fs\n", frame, GetTime());
    }
}