<?php

function ends_with($str, $key) {
    return strrpos($str, $key) == strlen($str) - strlen($key);
}

function ctype_alnum_underscore($str) {
    return ctype_alnum(str_replace('_', '', $str));
}

function &array_ensure_item_has_array(&$array, $key) {
    if (!array_key_exists($key, $array))
        $array[$key] = array();
    return $array[$key];
}

function array_get($array, $key, $default = NULL) {
    if (!array_key_exists($key, $array))
        return $default;
    return $array[$key];
}

function array_set_default(&$array, $key, $default) {
    if (!array_key_exists($key, $array))
        $array[$key] = $default;
}

$_config = NULL;

define('CONFIG_DIR', realpath(dirname(__FILE__) . '/../../'));

function config($key, $default = NULL) {
    global $_config;
    if (!$_config) {
        $file_path = getenv('ORG_WEBKIT_PERF_CONFIG_PATH');
        if (!$file_path)
            $file_path = CONFIG_DIR . '/config.json';
        $_config = json_decode(file_get_contents($file_path), true);
    }
    return array_get($_config, $key, $default);
}

function config_path($key, $path) {
    return CONFIG_DIR . '/' . config($key) . '/' . $path;
}

function same_till_last_occurrence_of_string($main_string, $comparing_string, $compare_to_last_position_string) {
    if (!$compare_to_last_position_string)
        return !strcmp($main_string, $comparing_string);

    $position_in_main_string = strrpos($main_string, $compare_to_last_position_string);
    $position_in_comparing_string = strrpos($comparing_string, $compare_to_last_position_string);
    if ($position_in_main_string !== $position_in_comparing_string)
        return FALSE;
    if ($position_in_main_string === FALSE)
        return !strcmp($main_string, $comparing_string);
    return !substr_compare($main_string, $comparing_string, 0, $position_in_main_string);
}

function generate_json_data_with_elapsed_time_if_needed($filename, $object, $elapsed_time) {
    if (!assert(ctype_alnum(str_replace(array('-', '_', '.'), '', $filename))))
        return NULL;

    $target_file_path = config_path('dataDirectory', $filename);
    $object['elapsedTime'] = $elapsed_time;
    $content = json_encode($object);

    if (file_exists($target_file_path) && same_till_last_occurrence_of_string(file_get_contents($target_file_path), $content, 'elapsedTime'))
        return $content;

    $temp_file_path = tempnam(config_path('dataDirectory', ''), $filename . '-temp-');
    file_put_contents($temp_file_path, $content, LOCK_EX);
    return rename($temp_file_path, $target_file_path) ?  $content : NULL;
}

if (config('debug')) {
    error_reporting(E_ALL | E_STRICT);
    ini_set('display_errors', 'On');
} else
    error_reporting(E_ERROR);

date_default_timezone_set('UTC');

class Database
{
    private $connection = false;

    function __destruct() {
        if ($this->connection)
            pg_close($this->connection);
        $this->connection = false;
    }

    static function is_true($value) {
        return $value == 't';
    }

    static function to_database_boolean($value) {
        return $value ? 't' : 'f';
    }

    static function to_js_time($time_str) {
        $timestamp_in_ms = strtotime($time_str) * 1000;
        $dot_index = strrpos($time_str, '.');
        if ($dot_index !== FALSE) {
            // Keep 5 decimal digits as postgres timestamp may only have 5 decimal digits.
            // Multiply by 1000 ahead to avoid losing precision. 1538041792.670479 will become 1538041792.6705 on php.
            $timestamp_in_ms += round(floatval(substr($time_str, $dot_index)), 5) * 1000;
        }
        return intval($timestamp_in_ms);
    }

    static function escape_for_like($string) {
        return str_replace(array('\\', '_', '%'), array('\\\\', '\\_', '\\%'), $string);
    }

    function connect() {
        $databaseConfig = config('database');
        $this->connection = @pg_connect('host=' . $databaseConfig['host'] . ' port=' . $databaseConfig['port']
            . ' dbname=' . $databaseConfig['name'] . ' user=' . $databaseConfig['username'] . ' password=' . $databaseConfig['password']);
        return $this->connection ? true : false;
    }

    private function prefixed_column_names($columns, $prefix = NULL) {
        if (!$prefix || !$columns)
            return join(', ', $columns);
        return $prefix . '_' . join(', ' . $prefix . '_', $columns);
    }

    private function prefixed_name($column, $prefix = NULL) {
        return $prefix ? $prefix . '_' . $column : $column;
    }

    private function prepare_params($params, &$placeholders, &$values, &$null_columns = NULL) {
        $column_names = array();

        $i = count($values) + 1;
        foreach (array_keys($params) as $name) {
            $current_value = $params[$name];
            if ($current_value === NULL && $null_columns !== NULL) {
                array_push($null_columns, $name);
                continue;
            }
            assert(ctype_alnum_underscore($name));
            array_push($column_names, $name);
            array_push($placeholders, '$' . $i);
            if (is_bool($current_value))
                $current_value = $this->to_database_boolean($current_value);
            array_push($values, $current_value);
            $i++;
        }

        return $column_names;
    }

    private function select_conditions_with_null_columns($prefix, $column_names, $placeholders, $null_columns) {
        $column_names = $this->prefixed_column_names($column_names, $prefix);
        $placeholders = join(', ', $placeholders);

        if (!$column_names && !$placeholders)
            $column_names = $placeholders = '1';
        $query = "($column_names) = ($placeholders)";
        foreach ($null_columns as $column_name)
            $query .= ' AND ' . $this->prefixed_name($column_name, $prefix) . ' IS NULL';
        return $query;
    }

    function insert_row($table, $prefix, $params, $returning = 'id') {
        $placeholders = array();
        $values = array();
        $column_names = $this->prepare_params($params, $placeholders, $values);

        assert(!$prefix || ctype_alnum_underscore($prefix));
        $column_names = $this->prefixed_column_names($column_names, $prefix);
        $placeholders = join(', ', $placeholders);

        $value_query = $column_names ? "($column_names) VALUES ($placeholders)" : ' VALUES (default)';
        if ($returning) {
            $returning_column_name = $this->prefixed_name($returning, $prefix);
            $rows = $this->query_and_fetch_all("INSERT INTO $table $value_query RETURNING $returning_column_name", $values);
            return $rows ? $rows[0][$returning_column_name] : NULL;
        }

        return $this->query_and_get_affected_rows("INSERT INTO $table $value_query", $values) == 1;
    }

    function select_or_insert_row($table, $prefix, $select_params, $insert_params = NULL, $returning = 'id') {
        return $this->_select_update_or_insert_row($table, $prefix, $select_params, $insert_params, $returning, FALSE, TRUE);
    }

    function update_or_insert_row($table, $prefix, $select_params, $insert_params = NULL, $returning = 'id') {
        return $this->_select_update_or_insert_row($table, $prefix, $select_params, $insert_params, $returning, TRUE, TRUE);
    }

    function update_row($table, $prefix, $select_params, $update_params, $returning = 'id') {
        return $this->_select_update_or_insert_row($table, $prefix, $select_params, $update_params, $returning, TRUE, FALSE);
    }

    private function _select_update_or_insert_row($table, $prefix, $select_params, $insert_params, $returning, $should_update, $should_insert) {
        $values = array();

        $select_placeholders = array();
        $select_null_columns = array();
        $select_column_names = $this->prepare_params($select_params, $select_placeholders, $values, $select_null_columns);
        $select_values = array_slice($values, 0);

        if ($insert_params === NULL)
            $insert_params = $select_params;
        $insert_placeholders = array();
        $insert_column_names = $this->prepare_params($insert_params, $insert_placeholders, $values);

        assert(!!$returning);
        assert(!$prefix || ctype_alnum_underscore($prefix));
        $returning_column_name = $returning == '*' ? '*' : $this->prefixed_name($returning, $prefix);

        $condition = $this->select_conditions_with_null_columns($prefix, $select_column_names, $select_placeholders, $select_null_columns);
        $query = "SELECT $returning_column_name FROM $table WHERE $condition";

        $insert_column_names = $this->prefixed_column_names($insert_column_names, $prefix);
        $insert_placeholders = join(', ', $insert_placeholders);

        // http://stackoverflow.com/questions/1109061/insert-on-duplicate-update-in-postgresql
        $rows = NULL;
        if ($should_update) {
            $rows = $this->query_and_fetch_all("UPDATE $table SET ($insert_column_names) = ($insert_placeholders)
                WHERE $condition RETURNING $returning_column_name", $values);
        }
        if (!$rows && $should_insert) {
            $rows = $this->query_and_fetch_all("INSERT INTO $table ($insert_column_names) SELECT $insert_placeholders
                WHERE NOT EXISTS ($query) RETURNING $returning_column_name", $values);
        }
        if (!$should_update && !$rows)
            $rows = $this->query_and_fetch_all($query, $select_values);

        return $rows ? ($returning == '*' ? $rows[0] : $rows[0][$returning_column_name]) : NULL;
    }

    function select_first_row($table, $prefix, $params, $order_by = NULL) {
        return $this->select_first_or_last_row($table, $prefix, $params, $order_by, FALSE);
    }

    function select_last_row($table, $prefix, $params, $order_by = NULL) {
        return $this->select_first_or_last_row($table, $prefix, $params, $order_by, TRUE);
    }

    private function select_first_or_last_row($table, $prefix, $params, $order_by, $descending_order) {
        $rows = $this->select_rows($table, $prefix, $params, $order_by, $descending_order, 0, 1);
        return $rows ? $rows[0] : NULL;
    }

    function select_rows($table, $prefix, $params,
        $order_by = NULL, $descending_order = FALSE, $offset = NULL, $limit = NULL) {

        $placeholders = array();
        $values = array();
        $null_columns = array();
        $column_names = $this->prepare_params($params, $placeholders, $values, $null_columns);
        $condition = $this->select_conditions_with_null_columns($prefix, $column_names, $placeholders, $null_columns);

        $query = "SELECT * FROM $table WHERE $condition";

        if ($order_by) {
            if (!is_array($order_by))
                $order_by = array($order_by);

            $order_columns = array();
            foreach ($order_by as $order_key) {
                assert(ctype_alnum_underscore($order_key));
                $order_column = $this->prefixed_name($order_key, $prefix) . ' ' . ($descending_order? 'DESC' : 'ASC');
                array_push($order_columns, $order_column);
            }
            $query .= ' ORDER BY ' . join(', ', $order_columns);
        }
        if ($offset !== NULL)
            $query .= ' OFFSET ' . intval($offset);
        if ($limit !== NULL)
            $query .= ' LIMIT ' . intval($limit);

        return $this->query_and_fetch_all($query, $values);
    }

    function query_and_get_affected_rows($query, $params = array()) {
        if (!$this->connection)
            return FALSE;
        $result = pg_query_params($this->connection, $query, $params);
        if (!$result)
            return FALSE;
        return pg_affected_rows($result);
    }

    function query_and_fetch_all($query, $params = array()) {
        if (!$this->connection)
            return NULL;
        $result = pg_query_params($this->connection, $query, $params);
        if (!$result)
            return NULL;
        if (pg_num_rows($result) == 0)
            return array();
        return pg_fetch_all($result);
    }

    function query($query, $params = array()) {
        if (!$this->connection)
            return FALSE;
        return pg_query_params($this->connection, $query, $params);
    }

    function fetch_next_row($result) {
        return pg_fetch_assoc($result);
    }

    function fetch_table($table_name, $column_to_be_ordered_by = null) {
        if (!$this->connection || !ctype_alnum_underscore($table_name) || ($column_to_be_ordered_by && !ctype_alnum_underscore($column_to_be_ordered_by)))
            return false;
        $clauses = '';
        if ($column_to_be_ordered_by)
            $clauses .= 'ORDER BY ' . $column_to_be_ordered_by;
        return $this->query_and_fetch_all("SELECT * FROM $table_name $clauses");
    }

    function begin_transaction() {
        return $this->connection and pg_query($this->connection, "BEGIN");
    }

    function commit_transaction() {
        return $this->connection and pg_query($this->connection, 'COMMIT');
    }

    function rollback_transaction() {
        return $this->connection and pg_query($this->connection, 'ROLLBACK');
    }

}

?>