<?php
/**
 * Utility functions for the Torn Vault Tracker application.
 *
 * This file contains helper functions for database operations, API calls,
 * and vault record management.
 *
 * PHP version 8.1+
 *
 * @category Utility
 * @package  TornVaultTracker
 * @author   Keith Solomon <ksolomon@gmail.com>
 * @license  Unlicense https://unlicense.org/
 * @link     https://github.com/ksolomon/Torn-Vault-Tracker
 */

/**
 * Checks if the database is new and empty.
 *
 * This function checks if the 'vault' table in the database has any entries.
 * If it does not, it returns true, indicating that the database is new and
 * empty. Otherwise, it returns false.
 *
 * @return boolean True if the database is new and empty, false otherwise.
 */
function dbNew() {
    $pdo  = getDatabaseConnection();
    $stmt = $pdo->query("SELECT COUNT(*) FROM vault");

    return $stmt->fetchColumn() == 0;
}

/**
 * Ensures that a user has an API key configured.
 *
 * @param string $user The user to check the API key for
 *
 * @return void
 *
 * @throws Exception If the user does not have an API key configured
 */
function ensureUserHasApiKey($user) {
    if (!array_key_exists($user, USER_KEYS)) {
        throw new ApiKeyMissingException("User does not have an API key configured.");
    }
}

/**
 * Executes a GET request to the given API endpoint and returns the JSON response as an associative array.
 *
 * Uses the v2 Torn API authentication scheme by sending the API key in an
 * `Authorization: ApiKey <key>` header. The key is never transmitted as a
 * query parameter.
 *
 * @param string $apiEndpoint The URL of the API endpoint to call
 * @param string $apiKey      The v2 API key to authenticate with
 *
 * @throws ApiKeyMissingException If the API key is empty
 * @throws CurlErrorException     If the cURL call fails
 * @throws JsonDataException      If the response body cannot be decoded as JSON
 *
 * @return array The JSON response from the API
 */
function executeApiCall($apiEndpoint, $apiKey) {
    if (empty($apiKey)) {
        throw new ApiKeyMissingException('API key is required for executeApiCall.');
    }

    $headers = ["Authorization: ApiKey $apiKey"];
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $apiEndpoint);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

    $response = curl_exec($ch);

    if (curl_errno($ch)) {
        throw new CurlErrorException("cURL error: " . curl_error($ch));
    }

    curl_close($ch);

    $responseData = json_decode($response, true);

    if (json_last_error() !== JSON_ERROR_NONE) {
        throw new JsonDataException("Failed to decode JSON response: " . json_last_error_msg());
    }

    return $responseData;
}

/**
 * Validates the API response data for the presence of a log array.
 *
 * @param array $responseData The API response data to validate.
 *
 * @return void
 *
 * @throws Exception If the log data is missing or not an array.
 */
function validateApiResponse($responseData) {
    if (!isset($responseData['log']) || !is_array($responseData['log'])) {
        throw new ApiValidationException('Invalid log data received from the API.');
    }
}

/**
 * Prepare a PDO statement for checking if a given vault transaction already exists in the database.
 *
 * @param PDO $pdo The PDO instance to prepare the statement with
 *
 * @return PDOStatement The prepared statement
 */
function prepareCheckStatement($pdo) {
    $checkQuery = "SELECT COUNT(*) FROM vault WHERE user = :user AND timestamp = :timestamp AND amount = :amount";
    return $pdo->prepare($checkQuery);
}

/**
 * Prepare a PDO statement for inserting a new vault transaction into the database.
 *
 * @param PDO $pdo The PDO instance to prepare the statement with
 *
 * @return PDOStatement The prepared statement
 */
function prepareInsertStatement($pdo) {
    $insertQuery = "INSERT INTO vault (ID, user, timestamp, description, amount) VALUES (:id, :user, :timestamp, :description, :amount)";
    return $pdo->prepare($insertQuery);
}

/**
 * Process an array of log entries retrieved from the Torn API.
 *
 * Goes through each log entry and checks if it's a vault deposit or withdrawal.
 * If it is, it checks if the entry already exists in the database. If it
 * doesn't, it inserts the entry into the database.
 *
 * @param array        $logEntries The array of log entries to process
 * @param string       $user       The user whose log entries are being processed
 * @param PDOStatement $checkStmt  A prepared statement to check if an entry
 *                                 already exists in the database
 * @param PDOStatement $insertStmt A prepared statement to insert a new entry
 *                                 into the database
 * @param boolean      $debug      Whether to output debug information (default: false)
 *
 * @return void
 */
function processLogEntries($logEntries, $user, $checkStmt, $insertStmt, $debug) {
    foreach ($logEntries as $key =>$entry) {
        if ($debug) {
            $logMessage = "Raw entry:\n" . print_r($entry, true);
            file_put_contents(__DIR__ . '/debug.log', $logMessage, FILE_APPEND);
        }

        $timestamp   = $entry['timestamp'];
        $description = $entry['title'];
        $amount      = $entry['log'] === 5850 ? $entry['data']['deposited'] : -$entry['data']['withdrawn'];

        if ($debug) {
            $logMessage = "Vault entry:\n\tUser: $user,\n\tTimestamp: $timestamp,\n\tDescription: $description,\n\tAmount: $amount\n";
            file_put_contents(__DIR__ . '/debug.log', $logMessage, FILE_APPEND);
        }

        $checkStmt->execute(
            [
            ':user'      => $user,
            ':timestamp' => $timestamp,
            ':amount'    => $amount
            ]
        );

        if ($checkStmt->fetchColumn() == 0) {
            $insertStmt->execute(
                [
                ':id'          => $key,
                ':user'        => $user,
                ':timestamp'   => $timestamp,
                ':description' => $description,
                ':amount'      => $amount
                ]
            );
        }
    }
}

/**
 * Fetch vault records from the database
 * If a user is provided, only that user's records
 * are returned. Otherwise, all records are returned.
 *
 * @param string $user (optional) The user to filter by
 *
 * @return array An array of records, or an empty array on error
 */
function fetchVaultRecords($user = null) {
    $pdo = getDatabaseConnection();

    if ($user) {
        $query  = "SELECT * FROM vault WHERE user = :user ORDER BY timestamp DESC";
        $params = [':user' => $user];
    } else {
        $query  = "SELECT * FROM vault ORDER BY timestamp DESC";
        $params = [];
    }

    try {
        $stmt = $pdo->prepare($query);
        $stmt->execute($params);

        return $stmt->fetchAll(PDO::FETCH_ASSOC);
    } catch (PDOException $e) {
        echo "Error fetching records: " . $e->getMessage();

        return [];
    }
}

/**
 * Iterate over all vault records for the given user (or all users if no user is given),
 *
 * @param string|null $name (optional) The user to loop over records for.
 *                          If not provided, all users' records will be looped over.
 *
 * @return int The total balance of the given user (or all users if no user is given).
 */
function vaultLoop ($name=null) {
    $vault   = fetchVaultRecords($name);
    $balance = 0;

    foreach ($vault as $entry) {
        $balance += $entry['amount'];
    }

    return $balance;
}

/**
 * Returns a string indicating the sign of a number, with a dollar symbol.
 *
 * @param int|float $number The number to check.
 *
 * @return string A string containing a dollar sign and a negative sign if the
 *                number is negative.
 */
function getSign($number) {
    if (substr($number, 0, 1) == '-') {
        return '-$';
    }

    return '$';
}