<?php

// Config

$GLOBALS["frairable_host"] = getenv("FRAIRABLE_HOST");
if (empty($GLOBALS["frairable_host"])) {
    $GLOBALS["frairable_host"] = "https://airable.wifiradiofrontier.com";
}

$GLOBALS["frairable_dir_radios"] = getenv("FRAIRABLE_DIR_RADIOS");
if (empty($GLOBALS["frairable_dir_radios"])) {
    $GLOBALS["frairable_dir_radios"] = dirname(__FILE__) . DIRECTORY_SEPARATOR . "radios";
}


// Common strings
$GLOBALS["frairable_part_custom"] = "custom=";
$GLOBALS["frairable_part_play"] = "play=";
$GLOBALS["frairable_uri_listing"] = "/frontiersmart/radios/custom";
$GLOBALS["frairable_uri_meta"] = "/frontiersmart/radio/$GLOBALS[frairable_part_custom]";


// Response utils

function respond_with_raw(&$data) {
    ob_start();
    {
        ob_start();
        {
            echo($data);
            ob_end_flush();
        }

        header("Content-Length: " . ob_get_length());
        ob_end_flush();
    }
}

function respond_with_json(&$data) {
    header("Content-Type: application/json");

    $data = json_encode($data);
    respond_with_raw($data);
}

function respond_with_proxy($cb = NULL) {
    $ch = curl_init("$GLOBALS[frairable_host]$_SERVER[REQUEST_URI]");

    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, $_SERVER["REQUEST_METHOD"]);
    curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_0 );

    $headers_req = getallheaders();
    curl_setopt($ch, CURLOPT_HTTPHEADER, [
        "Accept: " . ($headers_req["Accept"] ?? "audio/aac;mp3;dash"),
        "Accept-Language: " . ($headers_req["Accept-Language"] ?? "en-US"),
        "Authorization: " . ($headers_req["Authorization"] ?? "????"),
        "Connection: " . ($headers_req["Connection"] ?? "Close"),
        "Content-Length: " . ($headers_req["Content-Length"] ?? "0"),
        "User-Agent: " . ($headers_req["User-Agent"] ?? "ir-cui-FS2340-0000-0165_V4.5.13.707296-1A17")
    ]);

    curl_setopt($ch, CURLOPT_HEADERFUNCTION, function($curl, $headerstr) {
        $len = strlen($headerstr);
        $header = explode(":", $headerstr, 2);

        if (count($header) < 2) {
            return $len;
        }

        $key = trim($header[0]);
        $value = trim($header[1]);

        if ($key !== "Content-Length") {
            header($headerstr);
        }

        return $len;
    });

    $data = curl_exec($ch);
    $contentType = curl_getinfo($ch, CURLINFO_CONTENT_TYPE);
    $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);

    http_response_code($httpCode);

    if ($_SERVER["REQUEST_METHOD"] === "GET" && $httpCode === 200) {
        if ($cb !== NULL) {
            $data = json_decode($data, true);
            $cb($data);
            $data = json_encode($data);
        }

        if ($data === "null") {
            $data = "";

            if (200 <= $httpCode && $httpCode < 300) {
                http_response_code(404);
            }
        }
    }

    respond_with_raw($data);
}


// Radio data manglers

function get_radio_data($id) {
    $path = $GLOBALS["frairable_dir_radios"] . DIRECTORY_SEPARATOR . $id . ".json";
    $path = realpath($path);

    if (!str_starts_with($path, dirname(__FILE__))) {
        http_response_code(400);
        die();
    }

    return json_decode(file_get_contents($path), true);
}

function get_radio_entry($id) {
    $data = get_radio_data($id);

    $data["contains"] = [];

    // The ID MUST match with the URI for the radio meta.
    $data["id"] = ["frontiersmart", "radio", "$GLOBALS[frairable_part_custom]$id"];
    $data["url"] = "$GLOBALS[frairable_host]$GLOBALS[frairable_uri_meta]$id";

    unset($data["streams"]);

    return $data;
}

function get_radio_meta($id) {
    $data = get_radio_data($id);

    $data["id"] = ["frontiersmart", "radio", "$GLOBALS[frairable_part_custom]$id"];
    $data["url"] = "$GLOBALS[frairable_host]$GLOBALS[frairable_uri_meta]$id";

    foreach ($data["streams"] as $index => &$stream) {
        $stream["url"] = "$GLOBALS[frairable_host]$GLOBALS[frairable_uri_meta]$id/$GLOBALS[frairable_part_play]$index";
    }

    return $data;
}

function get_radio_play($id, $index) {
    $data = get_radio_data($id);

    // Clone loves to complain about the stream not being an object...
    // Deep clone using json is ugly, but eh.
    $stream = json_decode(json_encode($data["streams"][$index]), true);

    // The redirect ID can be anything, as long as it is unique.
    // It doesn't need to match with the URI.
    $stream["id"] = ["frontiersmart", "redirect", "$GLOBALS[frairable_part_custom]$id/$GLOBALS[frairable_part_play]$index"];
    $stream["content"] = $data;

    unset($stream["reliability"]);

    return $stream;
}


// Routing

if ($_SERVER["REQUEST_URI"] === "/frontiersmart/radios") {
    // Stock starting point - add our own entry here.

    respond_with_proxy(function(&$data) {
        array_push($data["content"]["entries"], [
            "id" => [
                "frontiersmart",
                "directory",
                "custom"
            ],
            "title" => "Frairable (Custom)",
            "url" => "$GLOBALS[frairable_host]$GLOBALS[frairable_uri_listing]"
        ]);
    });


} elseif ($_SERVER["REQUEST_URI"] === $GLOBALS["frairable_uri_listing"]) {
    // Our custom menu with our own entries.

    $entries = [];

    foreach (new DirectoryIterator($GLOBALS["frairable_dir_radios"]) as $sub) {
        if ($sub->isDot() || $sub->isDir()) {
            continue;
        }

        $id = basename($sub->getFilename(), ".json");

        $entries[] = get_radio_entry($id);
    }

    $data = [
        "id" => [
            "frontiersmart",
            "directory",
            "custom"
        ],
        "title" => "Frairable (Custom)",
        "url" => "$GLOBALS[frairable_host]$GLOBALS[frairable_uri_listing]",
        "content" => [
            "entries" => $entries
        ]
    ];

    respond_with_json($data);


} elseif (str_starts_with($_SERVER["REQUEST_URI"], $GLOBALS["frairable_uri_meta"])) {
    // The radio fetches different radio info multiple times:
    // - Metadata when selecting the entry, containing a list of streams.
    // - Playing info after the radio picked a stream to play.
    // See the dumped meta.json and play.json for more info.. and to witness the complex redundancy.

    $id = substr($_SERVER["REQUEST_URI"], strlen($GLOBALS["frairable_uri_meta"]));

    $split = strpos($id, "/$GLOBALS[frairable_part_play]");
    if ($split) {
        $index = intval(substr($id, $split + strlen("/$GLOBALS[frairable_part_play]")));
        $id = substr($id, 0, $split);
        respond_with_json(get_radio_play($id, $index));

    } else {
        respond_with_json(get_radio_meta($id));
    }


} else {
    respond_with_proxy();
}


?>