<?php
/**
 * Functions for the Torn Vault Tracker application.
 *
 * PHP version 8.1+
 *
 * @category Functions
 * @package  TornVaultTracker
 * @author   Keith Solomon <ksolomon@gmail.com>
 * @license  Unlicense https://unlicense.org/
 * @link     https://github.com/ksolomon/TornVaultTracker
 */

// Include settings from configuration file
require_once __DIR__ . '/config.php';

// Include utility functions
require_once 'includes/exceptions.php';
require_once 'includes/utilities.php';

/**
 * Returns a PDO connection to the database
 * This function creates the database connection and creates the database
 * file if it doesn't exist, and the vault table if it doesn't exist.
 *
 * @return PDO
 */
function getDatabaseConnection() {
    static $pdo = null;

    // SQL to create the vault table if it doesn't exist
    $createTableSQL = "CREATE TABLE IF NOT EXISTS vault (
        id TEXT PRIMARY KEY,
        user TEXT NOT NULL,
        timestamp INTEGER NOT NULL,
        description TEXT NOT NULL,
        amount REAL NOT NULL
    );";

    if ($pdo === null) {
        try {
            $pdo = new PDO(DB_DSN, DB_USER, DB_PASSWORD);
            $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

            $pdo->exec($createTableSQL);
        } catch (PDOException $e) {
            die("Database connection failed: " . $e->getMessage());
        }
    }

    return $pdo;
}

/**
 * Pulls and stores all vault transaction logs for a user from the Torn API.
 *
 * This function retrieves all transaction logs related to vault deposits and
 * withdrawals for a specified user. It continues fetching logs until no more
 * entries are available, and stores each entry in the database. Each log entry
 * is uniquely identified by its ID and includes details such as timestamp,
 * description, and amount. The function requires the user's API key to
 * authenticate requests to the Torn API.
 *
 * @param string $user The user whose transaction logs are to be retrieved and stored.
 *
 * @throws ApiKeyMissingException If the user does not have an API key configured.
 * @throws CurlErrorException If there is an error during the API call.
 * @throws Exception If there is an error decoding the JSON response or if the response is invalid.
 *
 * @return void
 */
function firstRun($user) {
    $apiKey = USER_KEYS[$user];
    $pdo    = getDatabaseConnection();
    $to     = time();

    do {
        $url = "https://api.torn.com/v2/user?selections=log&log=5850,5851&to=$to";
        $ch  = curl_init($url);

        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt(
            $ch, CURLOPT_HTTPHEADER, [
            'accept: application/json',
            "Authorization: ApiKey $apiKey"
            ]
        );

        $response = curl_exec($ch);

        curl_close($ch);

        $data = json_decode($response, true);

        if (empty($data['log'])) {
            break;
        }

        foreach ($data['log'] as $key => $entry) {
            $description = $entry['title'];
            $timestamp   = $entry['timestamp'];
            $amount      = isset($entry['data']['deposited']) ? $entry['data']['deposited'] : -$entry['data']['withdrawn'];

            $stmt = $pdo->prepare('INSERT INTO vault (ID, user, timestamp, description, amount) VALUES (:id, :user, :timestamp, :description, :amount)');

            $stmt->bindValue(':id', $key);
            $stmt->bindValue(':user', $user);
            $stmt->bindValue(':timestamp', $timestamp);
            $stmt->bindValue(':description', $description);
            $stmt->bindValue(':amount', $amount);

            $stmt->execute();
        }

        $to = end($data['log'])['timestamp'];
    } while (true);
}

/**
 * Retrieves the user's log entries from the Torn API
 *
 * @param string  $user  The user to retrieve the log for
 * @param boolean $debug Whether to output debug information (default: false)
 *
 * @throws Exception If the user does not have an API key configured,
 *                   if the API call fails, or if the log data is invalid
 *
 * @return void
 */
function getLog($user, $debug = false) {
    $pdo = getDatabaseConnection();

    ensureUserHasApiKey($user);

    $stmt = $pdo->query("SELECT MAX(timestamp) AS max_timestamp FROM vault WHERE user = '$user'");
    $row  = $stmt->fetch(PDO::FETCH_ASSOC);

    $from = $row['max_timestamp'];
    $to   = time();

    $apiKey      = USER_KEYS[$user];
    $apiEndpoint = "https://api.torn.com/user/?selections=log&log=5850,5851&to=$to&from=$from&key=$apiKey";

    $responseData = executeApiCall($apiEndpoint);
    validateApiResponse($responseData);

    $checkStmt  = prepareCheckStatement($pdo);
    $insertStmt = prepareInsertStatement($pdo);

    processLogEntries($responseData['log'], $user, $checkStmt, $insertStmt, $debug);
}

/**
 * Generate the current balance for a user or all users
 *
 * @param string $name (optional) The user to get the balance for. If not provided, all users' balances will be added.
 *
 * @return string The balance as a formatted string
 */
function generateBalance($name=null) {
    $balance = vaultLoop($name);

    return number_format($balance, 0); // Format the balance as an integer
}

/**
 * Calculate the available vault space for a user or all users.
 *
 * This function calculates the remaining space in the vault based on the
 * transactions for a specific user or all users. If a user is specified,
 * the available space is calculated against a limit of 500,000,000.
 * If no user is specified, the available space is calculated against a
 * total vault limit of 1,000,000,000.
 *
 * @param string|null $name (optional) The user to calculate the vault space for.
 *                          If not provided, calculates for all users.
 *
 * @return string The available vault space as a formatted string.
 */
function getSpace($name=null) {
    $space = vaultLoop($name);

    if ($name === null) {
        $space = 1000000000 - $space;
    } else {
        $space = 500000000 - $space;
    }

    return number_format($space, 0); // Format the balance as an integer
}

/**
 * Builds an HTML table of all transactions in the vault
 *
 * Loops over all records in the vault and builds a table of the user, timestamp,
 * description and amount of each transaction. Amounts are formatted as integers.
 *
 * @return void
 */
function buildTable () {
    $records = fetchVaultRecords();

    foreach ($records as $entry) {
        $user        = $entry['user'];
        $timestamp   = $entry['timestamp'];
        $description = $entry['description'];
        $amount      = $entry['amount'];
        $sign        = getSign($amount);

        if ($description == 'Vault withdraw') {
            $class  = 'debit';
            $amount = substr($amount, 1); // Remove the negative sign
        } else {
            $class  = 'credit';
        }

        $amount = number_format($amount, 0); // Format the amount as an integer

        echo '<tr class="'.$class.'">';
        echo '<td>'.$user.'</td>';
        echo '<td>'.date("F j, Y / H:i", $timestamp).'</td>';
        echo '<td>'.$description.'</td>';
        echo '<td>'.$sign.$amount.'</td>';
        echo '</tr>';
    }
}