<?php

define("VERSION", "2.1.0");

/**
 * Load and parse the config file, setting any defaults here if non-required
 * fields are not set
 *
 * @return string[]
 * @author Phil Burton <phil@pgburton.com>
 * @throws Exception when file is not readable
 * @throws Exception when ini file fails to parse
 * @throws Exception when url not found in ini file
 * @throws Exception when command not found in ini file
 * @throws Exception when pagesize is set incorrectly
 */
function getConfig()
{
    $config = false;

    if (!is_readable("config.ini")) {
        throw new Exception('File config.ini does not exist');
    }
    if (!$config = parse_ini_file("config.ini")) {
        throw new Exception('Could not parse ini file', 1);
    }
    if (!isset($config["url"])) {
        throw new Exception('`url` not found in ini file', 1);
    }
    if (!isset($config["command"])) {
        throw new Exception('`command` not found in ini file', 1);
    }

    // Set default page size if it's not in the config
    if (!isset($config["pagesize"])) {
        $config["pagesize"] = 3;
    } elseif (!is_int((int)$config["pagesize"]) || $config["pagesize"] < 1) {
        throw new Exception('Page size ' . $config["pagesize"]  . ' not valid in config', 1);
    }
    // hash the password
    if (isset($config['password'])) {
        $config['hash'] = hash("sha256", $config['password']);
    }
    return $config;
}

/**
 * Use curl to find get the plain text file for a url
 * Using the sha256 hashed password if it's been set in the config
 *
 * @param  string[] $config
 * @return StdClass[]
 * @author Phil Burton <phil@pgburton.com>
 */
function getResultsFromUrl($config)
{
    $curl = curl_init($config["url"] . "?format=plain");
    if (isset($config["hash"])) {
        curl_setopt($curl, CURLOPT_HTTPHEADER, array("Cookie: password=" . $config["hash"]));
    }
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
    $output = explode("\n", curl_exec($curl));
    curl_close($curl);

    if (!isset($output)) {
        throw new Exception(
            "Could not retrive results from http server `"
            . $config["url"]
            . "?format=json` using password="
            . (isset($config["hash"]) ? "true" : "false"),
            1
        );
    }
    return $output;
}

/**
 * Return the help text
 *
 * @param  StdClass[] $config
 * @return string
 * @author Phil Burton <phil@pgburton.com>
 */
function getHelp($config)
{
    return "Usage: !" . $config["command"] . " [query] #[page] | "
        . "e.g: !" . $config["command"] . " intense | "
        . "!" . $config["command"] . " intense marcus | "
        . "!" . $config["command"] . " intense marcus #2 (returns the second page of results)";
}

/**
 * Get the version string
 *
 * @param  stdClass[] $config
 * @return string
 * @author Phil Burton <phil@pgburton.com>
 */
function getVersion($config)
{
    return $config["command"] . " v" . VERSION;
}

/**
 * Output the given string, adding a new line at the end
 * If pieces is an array, use the glue to implode and output a single string
 *
 * EXIT
 *
 * @param  string|string[] $pieces
 * @param  string $glue
 * @param  bool $sderr
 * @author Phil Burton <phil@pgburton.com>
 */
function output($pieces, $glue = " - ", $stderr = false)
{
    $out = "";
    if (!is_array($pieces)) {
        $out = $pieces . "\n";
    } else {
        $out = implode($glue, $pieces) . "\n";
    }

    if ($stderr) {
        fwrite(STDERR, $out . "\n");
    } else {
        echo $out;
    }

    exit;
}

/**
 * Read stdin and return as a string
 *
 * @return string
 * @author Phil Burton <phil@pgburton.com>
 */
function read_stdin()
{
    $fr = fopen("php://stdin", "r");
    $input = fgets($fr, 128);
    $input = rtrim($input);
    fclose($fr);
    return $input;
}

/**
 * Get the start and end index positions for the required page and
 * page size
 *
 * @param  int $page
 * @param  int $pagesize
 * @return int[]
 * @author Phil Burton <phil@pgburton.com>
 */
function getPaginationBounds($page, $pagesize)
{
    return [
        "start" => ($page - 1) * $pagesize,
        "end" => (($page - 1) * $pagesize) + ($pagesize - 1)
    ];
}

/**
 * Loop through the stdin and parse the arguments given
 * If we hit a "special" argument then run the specific code and exit
 * Otherwise we set the page and search terms and return them as an array
 *
 * @param  $config
 * @return mixed[]
 * @author Phil Burton <phil@pgburton.com>
 */
function getFormattedArguments($config)
{
    $args = explode(" ", read_stdin());

    if (!isset($args) || empty($args)) {
        throw new Exception("No arguments found");
    }
    // Loop the raw arguments and create our formated argument array
    $formatArgs = [];
    $formatArgs["search"] = [];
    foreach ($args as $arg) {
        // Switch to check for special arguments
        // output should exit but incase it errors we double break
        switch ($arg) {
            case "--version":
            case "-v": // Flow through
                output(getVersion($config));
                break 2;
            case "--help":
            case "-h": // Flow through
                output(getHelp($config));
                break 2;
        }

        // Check to see if we have a page specified
        if (strpos($arg, "#") === 0) {
            $formatArgs["page"] = substr($arg, 1);
            continue;
        }

        // If we reach here, then the argument is a search term
        $formatArgs["search"][] = $arg;
    }

    // If we reach this point we must have at least one search term
    if (empty($formatArgs["search"])) {
        throw new Exception("Please Enter a search term");
    }

    if (!isset($formatArgs["page"])) {
        $formatArgs["page"] = 1;
    } elseif (!is_int((int)$formatArgs["page"]) || $formatArgs["page"] < 1) {
        throw new Exception("Page number `" . $formatArgs["page"] . "` is not valid");
    }

    return $formatArgs;
}

/*********************************
 * ENTRY POINT FOR FUNCTION HERE *
 *********************************/
try {
    $config = getConfig();
    $content = getResultsFromUrl($config);
    $arguments = getFormattedArguments($config);

    // parse the arguments
    $page = $arguments["page"];

    $out = [];

    // Really slow search
    $results = [];
    $regex = "";
    foreach ($arguments["search"] as $arg) {
        $regex .= "(?=.*" . $arg . ")";
    }
    $content = preg_grep("/" . $regex . "/i", $content);
    $results = $content;

    if (empty($results)) {
        output("No results found");
    }

    $count = count($results);
    $i = 0;
    $bounds = getPaginationBounds($page, $config["pagesize"]);

    if ($bounds["start"] > ($count - 1)) {
        throw new Exception("No results for this page");
    }

    foreach ($results as $result) {
        if ($i < $bounds["start"] || $i > $bounds["end"]) {
            $i++;
            continue;
        }
        $out[] = $i + 1 . ": " . $config["url"] . "/" . rawurlencode($result);
        $i++;
    }

    if ($count > 3) {
        $out[] = "results (" . $count . ")";
    }

    output($out);

} catch (Exception $e) {
    output($e->getMessage(), " - ", ($e->getCode() == 1));
}