<?php

use FFMpeg\Coordinate\TimeCode;
use FFMpeg\FFMpeg;
use FFMpeg\FFProbe;
use mystic\forum\orm\Attachment;

$attId = $_GET["attachment"] ?? throw new Exception("Missing attachment id");
$attachment = new Attachment();
$attachment->id = $attId;
if (!$db->fetch($attachment)) {
    http_response_code(404);
    msg_error(__("No attachment exists with this id"));
    exit;
}

$isImage = str_starts_with($attachment->mimeType, "image/");
$isVideo = str_starts_with($attachment->mimeType, "video/");

if (!$isImage && !$isVideo) {
    http_response_code(400);
    msg_error(__("Attachment is neither an image nor a video"));
    exit;
}

$contentHash = hash("sha256", $attachment->contents);

$cacheId = bin2hex($attachment->id);
$cacheDir = sys_get_temp_dir() . "/mystic/forum/0/cache/thumbs/" . substr($cacheId, 0, 2) . "/" . substr($cacheId, 0, 8) . "/";
if (!is_dir($cacheDir))
    mkdir($cacheDir, recursive: true);

$cacheFileData = $cacheDir . $cacheId . ".data";
$cacheFileInfo = $cacheDir . $cacheId . ".info";

if (is_file($cacheFileData) && is_file($cacheFileInfo)) {
    $info = json_decode(file_get_contents($cacheFileInfo));
    if ($info->contentHash === $contentHash) {
        header("Content-Type: image/jpeg");
        header("Cache-Control: max-age=86400");
        //header("X-Debug-Content: $cacheFileData");
        readfile($cacheFileData);
        exit;
    }
}

if ($isVideo) {
    $suffix = (microtime(true) * 1000) . "-" . random_int(0, 99999);
    $tempVid = sys_get_temp_dir() . "/video_" . $suffix;
    file_put_contents($tempVid, $attachment->contents);
    $tempImg = sys_get_temp_dir() . "/image_" . $suffix . ".jpg";

    try {
        $ffprobe = FFProbe::create();
        /** @var string $duration */
        $duration = $ffprobe
            ->format($tempVid)
            ->get("duration", "0");

        $screenshotFramePoint = TimeCode::fromSeconds(floatval($duration) / 2.0);
        
        $ffmpeg = FFMpeg::create();
        $video = $ffmpeg->open($tempVid);
        $screenshot = $video
            ->frame($screenshotFramePoint)
            ->save($tempImg);
        $im = imagecreatefromjpeg($tempImg);
    } finally {
        if (is_file($tempVid)) unlink($tempVid);
        if (is_file($tempImg)) unlink($tempImg);
    }
} elseif ($isImage) {
    $im = imagecreatefromstring($attachment->contents);
}

$w = imagesx($im);
$h = imagesy($im);
$r = $w / floatval($h);

if ($w > $h) {
    $nw = THUMB_MAX_DIM;
    $nh = floor($nw / $r);
} else {
    $nh = THUMB_MAX_DIM;
    $nw = floor($r * $nh);
}

$thumb = imagecreatetruecolor($nw, $nh);
imagecopyresampled($thumb, $im, 0, 0, 0, 0, $nw, $nh, $w, $h);
imagedestroy($im);

header("Content-Type: image/jpeg");
header("Cache-Control: max-age=86400");
imagejpeg($thumb, $cacheFileData, 40);
imagedestroy($thumb);
file_put_contents($cacheFileInfo, json_encode([
    "format" => 1,
    "contentHash" => $contentHash,
    "created" => time(),
], JSON_UNESCAPED_SLASHES));
readfile($cacheFileData);