module gg

import encoding.base64
import sokol.sapp
import os

fn screenshot_stdout_payload(frame u64, png []u8) string {
    return '${gg_record_stdout_prefix} frame=${frame} format=png encoding=base64 data=${base64.encode(png)}'
}

fn emit_recorded_frame_to_stdout(frame u64) ! {
    screenshot_file_path := os.join_path(os.vtmp_dir(),
        'vgg_record_stdout_${os.getpid()}_${frame}.png')
    sapp.screenshot_png(screenshot_file_path)!
    defer {
        os.rm(screenshot_file_path) or {}
    }
    png := os.read_bytes(screenshot_file_path)!
    println(screenshot_stdout_payload(frame, png))
    flush_stdout()
}

// record_frame records the current frame to a file or stdout.
// record_frame acts according to settings specified in `gg.recorder_settings`.
@[if gg_record ?]
pub fn (mut ctx Context) record_frame() {
    if ctx.frame in recorder_settings.screenshot_frames {
        match recorder_settings.screenshot_output {
            .stdout {
                $if gg_record_trace ? {
                    eprintln('>>> screenshotting frame ${ctx.frame} to stdout')
                }
                emit_recorded_frame_to_stdout(ctx.frame) or { panic(err) }
            }
            .file {
                screenshot_file_path := '${recorder_settings.screenshot_prefix}${ctx.frame}.png'
                $if gg_record_trace ? {
                    eprintln('>>> screenshotting ${screenshot_file_path}')
                }
                sapp.screenshot_png(screenshot_file_path) or { panic(err) }
            }
        }
    }
    if ctx.frame == recorder_settings.stop_at_frame {
        $if gg_record_trace ? {
            eprintln('>>> exiting at frame ${ctx.frame}')
        }
        flush_stdout()
        exit(0)
    }
}

fn new_gg_recorder_settings() &SSRecorderSettings {
    $if gg_record ? {
        return new_gg_recorder_settings_from_env(os.environ(), os.executable())
    } $else {
        return &SSRecorderSettings{}
    }
}

const recorder_settings = new_gg_recorder_settings()