<?php
namespace Core;

use App\Config;

abstract class Model
{
    protected static $conn = null;

    abstract public function showAll();

    abstract public function showSingle($id);

    protected static function connectDB()
    {
        try {
            if (!self::$conn) {
                $dsn = 'mysql:host='.Config::DB_HOST.';dbname='.Config::DB_DB;
                self::$conn = new \PDO($dsn, Config::DB_UNAME, Config::DB_PWD);

                self::$conn->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
            }
            return self::$conn;
        } catch (PDOException $e) {
            echo $e->getMessage();
        }
    }

    public function createTable($table, $fields = [])
    {
        $sql = "CREATE TABLE IF NOT EXISTS {$table} (".implode(',', $fields).") ENGINE=InnoDB DEFAULT CHARSET=utf8;";

        $db = static::connectDB();
        $query = $db->prepare($sql);

        if ($query->execute()) {
            return true;
        }
        return false;
    }

    public function dropTable($table)
    {
        if (is_array($table)) {
            if (count($table)) {
                $table = implode(', ', $table);
            }
        }
        $sql = "DROP TABLE IF EXISTS {$table}";

        $db = static::connectDB();
        $query = $db->prepare($sql);

        if ($query->execute()) {
            return true;
        }
        return false;
    }

    public function entry($table, $args, $values = '')
    {
        if (count($args)) {
            $keys = '`'.implode('`, `', array_keys($args)).'`';

            // This is if want to insert multiple rows
            foreach ($args as $key => $val) {
                if (preg_match('/,/', $val)) {
                    $val = explode(',', $val);
                    $args[$key] = $val;
                }
            }

            $x = 1;
            foreach ($args as $field) {
                // Setting the query for multiple rows
                if (is_array($field)) {
                    foreach ($field as $fields) {
                        $values .= '(?)';
                        if ($x < count($field)) {
                            $values .= ', ';
                        }
                        $x++;
                    }
                } else {
                    if ($x === 1) {
                        $values .= '(';
                    }
                    $values .= '?';
                    if ($x < count($args)) {
                        $values .= ', ';
                    } else {
                        $values .= ')';
                    }
                    $x++;
                }
            }

            try {
                $sql = "INSERT INTO {$table} ({$keys}) VALUES {$values}";

                $db = static::connectDB();

                $query = $db->prepare($sql);

                $x = 1;
                foreach ($args as $value) {
                    if (is_array($value)) {
                        foreach ($value as $vals) {
                            $query->bindValue($x, $vals);
                            $x++;
                        }
                    } else {
                        $query->bindValue($x, $value);
                        $x++;
                    }
                }

                if ($query->execute()) {
                    return true;
                }
                return false;
            } catch (PDOException $e) {
                echo $e->getMessage();
            }
        }
    }

    public function update($table, $args, $id)
    {
        if (count($args)) {
            $keys = array_keys($args);

            $fields = [];
            foreach ($keys as $key) {
                $fields[] = $key.' = ?';
            }

            if (count($fields) > 1) {
                $fields = implode(', ', $fields);
            } else {
                $fields = implode('', $fields);
            }

            try {
                $db = static::connectDB();

                $sql = "UPDATE {$table} SET {$fields} WHERE id = ?";

                $query = $db->prepare($sql);
                $x = 1;
                foreach ($args as $value) {
                    $query->bindValue($x, $value);
                    $x++;
                }
                $query->bindValue($x, $id);

                if ($query->execute()) {
                    return true;
                }
                return false;
            } catch (PDOException $e) {
                echo $e->getMessage();
            }
        }
    }

    public function delete($table, $id)
    {
        try {
            $db = static::connectDB();

            $sql = "DELETE FROM {$table} WHERE id = ?";

            $query = $db->prepare($sql);

            if ($query->execute([$id])) {
                return true;
            }
            return false;
        } catch (PDOException $e) {
            echo $e->getMessage();
        }
    }
}