<?php
namespace core\base;

/**
 * 模型基类 - 修复版
 */
class Model
{
    protected $table = '';
    protected $pdo = null;
    protected $where = array();
    protected $params = array();
    protected $order = '';
    protected $limit = '';
    protected $fields = '*';
    protected $lastError = '';

    /** 表前缀，统一为 DGZXY_ */
    const TABLE_PREFIX = 'DGZXY_';

    public function __construct()
    {
        $this->pdo = \core\db\Db::pdo();
    }

    /**
     * 获取带前缀的完整表名
     */
    public function getTable()
    {
        // 如果已包含前缀则不重复添加
        if (strpos($this->table, self::TABLE_PREFIX) === 0) {
            return $this->table;
        }
        return self::TABLE_PREFIX . $this->table;
    }

    // 设置表名（外部调用 table() 时传入不带前缀的原始表名）
    public function table($table)
    {
        $this->table = $table;
        return $this;
    }

    // 设置查询字段
    public function field($fields)
    {
        $this->fields = $fields;
        return $this;
    }

    // 设置 WHERE 条件
    public function where($where = null, $params = array())
    {
        if ($where !== null) {
            $this->where = $where;
            $this->params = $params;
        }
        return $this;
    }

    // 设置排序 - 修复版
    public function order($order)
    {
        if (is_array($order)) {
            // 支持两种格式：
            // 1. ['id DESC'] -> "id DESC"
            // 2. ['id' => 'DESC'] -> "id DESC"
            $parts = [];
            foreach ($order as $key => $value) {
                if (is_numeric($key)) {
                    // 格式：['id DESC']
                    $parts[] = $value;
                } else {
                    // 格式：['id' => 'DESC']
                    $parts[] = $key . ' ' . $value;
                }
            }
            $this->order = implode(', ', $parts);
        } else {
            // 字符串格式：'id DESC'
            $this->order = $order;
        }
        return $this;
    }

    // 设置 LIMIT
    public function limit($limit)
    {
        $this->limit = $limit;
        return $this;
    }

    // 获取单条记录
    public function fetch()
    {
        $sql = $this->buildSelect();
        $stmt = $this->pdo->prepare($sql);
        $stmt->execute($this->params);
        return $stmt->fetch();
    }

    // 获取所有记录
    public function fetchAll()
    {
        $sql = $this->buildSelect();
        $stmt = $this->pdo->prepare($sql);
        $stmt->execute($this->params);
        return $stmt->fetchAll();
    }

    // 构建 SELECT 语句
    protected function buildSelect()
    {
        $sql = 'SELECT ' . $this->fields . ' FROM ' . $this->getTable();
        
        if (!empty($this->where)) {
            if (is_string($this->where)) {
                $sql .= ' WHERE ' . $this->where;
            } else if (is_array($this->where)) {
                $sql .= ' WHERE ' . implode(' AND ', $this->where);
            }
        }
        
        if (!empty($this->order)) {
            $sql .= ' ORDER BY ' . $this->order;
        }
        
        if ($this->limit) {
            $sql .= ' LIMIT ' . $this->limit;
        }
        
        return $sql;
    }

    // 获取最后错误信息
    public function getError()
    {
        return $this->lastError;
    }

    // 添加记录
    public function add($data)
    {
        $fields = implode(', ', array_keys($data));
        $placeholders = ':' . implode(', :', array_keys($data));
        $sql = 'INSERT INTO ' . $this->getTable() . ' (' . $fields . ') VALUES (' . $placeholders . ')';
        
        $stmt = $this->pdo->prepare($sql);
        $result = $stmt->execute($data);
        if ($result === false) {
            $err = $stmt->errorInfo();
            $this->lastError = isset($err[2]) ? $err[2] : 'Unknown error';
        }
        return $result;
    }

    // 更新记录
    public function update($data)
    {
        $set = array();
        $params = array();
        foreach ($data as $key => $value) {
            $set[] = $key . ' = :' . $key;
            $params[':' . $key] = $value;
        }
        
        $sql = 'UPDATE ' . $this->getTable() . ' SET ' . implode(', ', $set);
        
        if (!empty($this->where)) {
            if (is_string($this->where)) {
                $sql .= ' WHERE ' . $this->where;
            } else if (is_array($this->where)) {
                $sql .= ' WHERE ' . implode(' AND ', $this->where);
            }
        }
        
        // 合并 WHERE 参数
        foreach ($this->params as $key => $value) {
            $params[$key] = $value;
        }
        
        $stmt = $this->pdo->prepare($sql);
        return $stmt->execute($params);
    }

    // 删除记录（按 id）
    public function delete($id)
    {
        $sql = 'DELETE FROM ' . $this->getTable() . ' WHERE id = :id';
        $stmt = $this->pdo->prepare($sql);
        return $stmt->execute(array(':id' => $id));
    }

    // 按 where 条件删除记录
    public function deleteWhere()
    {
        if (empty($this->where)) {
            return false;
        }
        $sql = 'DELETE FROM ' . $this->getTable();
        if (is_string($this->where)) {
            $sql .= ' WHERE ' . $this->where;
        } else if (is_array($this->where)) {
            $sql .= ' WHERE ' . implode(' AND ', $this->where);
        }
        $stmt = $this->pdo->prepare($sql);
        $result = $stmt->execute($this->params);
        // 清除 where 条件
        $this->where = array();
        $this->params = array();
        return $result;
    }

    // 执行原生 SQL
    public function query($sql, $params = array())
    {
        $stmt = $this->pdo->prepare($sql);
        $stmt->execute($params);
        $rows = $stmt->fetchAll();
        // 释放结果集游标，避免复用同一 PDO 连接时触发 2014 错误
        $stmt->closeCursor();
        return $rows;
    }

    // 执行原生 SQL（无返回）
    public function execute($sql, $params = array())
    {
        $stmt = $this->pdo->prepare($sql);
        return $stmt->execute($params);
    }
}