<?php
function generate_message_screenshot(GdImage $pfp, string $username, string $channel, string $message, int $timestamp): GdImage
{
    $font_size = 18;
    $font_path = './static/ttf/Arial.ttf';
    $width = 500;
    $height = 200;
    $pad_x = 24;
    $spacing = 4;

    // dividing the message lines
    $message_lines = [];
    $max_line_width = $width - $pad_x * 4;
    $buffer_line = "";
    $buffer_part = "";

    foreach (str_split($message) as $c) {
        $buffer_part .= $c;

        $bbox_line = imagettfbbox($font_size, 0, $font_path, $buffer_line);
        $bbox_part = imagettfbbox($font_size, 0, $font_path, $buffer_part);

        $line_width = abs($bbox_line[2] - $bbox_line[0]);
        $line_width += abs($bbox_part[2] - $bbox_part[0]);

        if ($line_width >= $max_line_width) {
            if (empty($buffer_line)) {
                $buffer_line .= $buffer_part;
                $buffer_part = "";
            }

            array_push($message_lines, $buffer_line);
            $buffer_line = "";
        }

        if ($c == ' ') {
            $buffer_line .= $buffer_part;
            $buffer_part = "";
        }
    }

    if (!empty($buffer_part)) {
        $buffer_line .= $buffer_part;
    }

    array_push($message_lines, $buffer_line);

    // counting real image height
    for ($i = 0; $i < count($message_lines); $i++) {
        $h = $pad_x + imagesy($pfp) + $font_size * $i + $spacing * $i;
        if ($h + $font_size * 2 >= $height) {
            $height += $font_size + $spacing;
        }
    }

    $height += $font_size + $pad_x + $spacing;

    $image = imagecreate($width, $height);

    $gray_color = imagecolorallocate($image, 50, 50, 50);
    $black_color = imagecolorallocate($image, 0, 0, 0);
    $white_color = imagecolorallocate($image, 255, 255, 255);

    // setting the background
    imagefilledrectangle($image, 0, 0, $width, $height, $white_color);

    // setting the user's pfp
    imagecopy(
        $image,
        $pfp,
        $pad_x,
        $pad_x,
        0,
        0,
        imagesx($pfp),
        imagesy($pfp)
    );

    // setting the username and the channel name
    imagettftext(
        $image,
        $font_size,
        0,
        imagesx($pfp) + 32,
        imagesy($pfp) / 2 + $pad_x,
        $black_color,
        $font_path,
        $username
    );

    imagettftext(
        $image,
        $font_size - 2,
        0,
        imagesx($pfp) + 32,
        imagesy($pfp) / 2 + $pad_x + $font_size,
        $gray_color,
        $font_path,
        "in #{$channel}"
    );

    // setting the message
    for ($i = 0; $i < count($message_lines); $i++) {
        $h = 32 + $pad_x + imagesy($pfp) + $font_size * $i + $spacing * $i;
        imagettftext(
            $image,
            $font_size,
            0,
            $pad_x,
            $h,
            $black_color,
            $font_path,
            $message_lines[$i]
        );
    }

    // drawing the twitch logo

    // setting the date
    imagettftext(
        $image,
        $font_size - 4,
        0,
        $pad_x,
        $height - $pad_x,
        $gray_color,
        $font_path,
        date("F j, Y · G:i", $timestamp) . ' (UTC)'
    );

    return $image;
}