<?php

namespace base\common\service\scheme;

use think\facade\Db;
use think\facade\Config;
use app\common\scheme\attribute\Table;
use app\common\scheme\attribute\Field;
use app\common\scheme\attribute\Component;
use app\common\scheme\attribute\Index;
use ReflectionClass;
use ReflectionProperty;

class SchemeToDbService
{
    protected $connection;

    public function __construct()
    {
        $this->connection = Config::get('database.default', 'mysql');
    }

    public function sync(string $className, bool $skipData = false)
    {
        if (!class_exists($className)) {
            throw new \Exception("Class $className not found");
        }

        $ref = new ReflectionClass($className);
        
        // 获取 Table 注解
        $tableAttrs = $ref->getAttributes(Table::class);
        if (empty($tableAttrs)) {
            throw new \Exception("Class $className missing #[Table] attribute");
        }
        /** @var Table $tableAttr */
        $tableAttr = $tableAttrs[0]->newInstance();
        
        $tableName = $tableAttr->name;
        $prefix = Config::get('database.connections.' . $this->connection . '.prefix', '');
        
        // 确保表名带前缀
        $fullTableName = $tableName;
        if ($prefix && !str_starts_with($tableName, $prefix)) {
            $fullTableName = $prefix . $tableName;
        }

        // 检查表是否存在
        $tableExists = $this->checkTableExists($fullTableName);
        $backupTableName = null;

        // 1. 备份
        if ($tableExists) {
            $backupPrefix = Config::get('scheme.backup_prefix', 'backup');
            $backupTableName = $prefix . $backupPrefix . '_' . date('YmdHis') . '_' . $fullTableName;
            
            try {
                // 确保没有残留的同名备份表（极端情况）
                Db::connect($this->connection)->execute("DROP TABLE IF EXISTS `$backupTableName`");
                Db::connect($this->connection)->execute("RENAME TABLE `$fullTableName` TO `$backupTableName`");
            } catch (\Exception $e) {
                // 如果备份失败，可能是权限问题或其他，抛出异常
                throw new \Exception("Backup failed: " . $e->getMessage());
            }
        }

        // 2. 建表
        $sql = $this->buildCreateTableSql($fullTableName, $tableAttr, $ref);
        Db::connect($this->connection)->execute($sql);

        // 3. 恢复数据
        if ($tableExists && !$skipData && $backupTableName) {
            try {
                $this->restoreData($fullTableName, $backupTableName, $ref->getProperties());
            } catch (\Exception $e) {
                // 如果数据恢复失败，尝试回滚（这里只是简单的删除新表，重命名回旧表）
                // 实际生产环境可能需要更复杂的恢复机制
                // Db::connect($this->connection)->execute("DROP TABLE IF EXISTS `$fullTableName`");
                // Db::connect($this->connection)->execute("RENAME TABLE `$backupTableName` TO `$fullTableName`");
                throw $e;
            }
        }
        
        return $backupTableName;
    }

    protected function checkTableExists($tableName)
    {
        $tables = Db::connect($this->connection)->query("SHOW TABLES LIKE '$tableName'");
        return !empty($tables);
    }

    protected function buildCreateTableSql($tableName, Table $tableAttr, ReflectionClass $ref)
    {
        $properties = $ref->getProperties();
        $lines = [];
        $primaryKeys = [];
        
        foreach ($properties as $prop) {
            $fieldAttrs = $prop->getAttributes(Field::class);
            if (empty($fieldAttrs)) {
                continue;
            }
            /** @var Field $field */
            $field = $fieldAttrs[0]->newInstance();
            $fieldName = $prop->getName();
            
            $line = "`$fieldName` {$field->type}";
            
            // Length/Precision
            if ($field->length !== null) {
                $line .= "({$field->length})";
            } elseif ($field->precision > 0) {
                $line .= "({$field->precision},{$field->scale})";
            }
            
            // Unsigned
            if ($field->unsigned) {
                $line .= " UNSIGNED";
            }
            
            // Nullable
            if (!$field->nullable) {
                $line .= " NOT NULL";
            } else {
                $line .= " DEFAULT NULL";
            }
            
            // AutoIncrement
            if ($field->autoIncrement) {
                $line .= " AUTO_INCREMENT";
            }
            
            // Default
            if (!is_null($field->default)) {
                $def = $field->default;
                if (is_string($def)) {
                    $line .= " DEFAULT '$def'";
                } elseif (is_bool($def)) {
                    $line .= " DEFAULT " . ($def ? 1 : 0);
                } else {
                    $line .= " DEFAULT $def";
                }
            }

            // Comment + Component Restore
            $comment = $field->comment;
            
            // 检查是否有 Component 注解
            $compAttrs = $prop->getAttributes(Component::class);
            if (!empty($compAttrs)) {
                /** @var Component $comp */
                $comp = $compAttrs[0]->newInstance();
                $typeStr = "{{$comp->type}}";
                $optionsStr = '';
                if (!empty($comp->options)) {
                    $parts = [];
                    foreach ($comp->options as $k => $v) {
                        // 如果是数字索引，且连续，可能就是简单的值列表？
                        // 但 Ulthon 格式通常是 k:v。如果 k 是数字，也要输出。
                        $parts[] = "$k:$v";
                    }
                    $optionsStr = ' (' . implode(',', $parts) . ')';
                }
                // 拼接回注释：原注释 {type} (options)
                $comment = trim($comment . " $typeStr$optionsStr");
            }
            
            if ($comment) {
                $line .= " COMMENT '$comment'";
            }
            
            $lines[] = $line;
            
            if ($field->primary) {
                $primaryKeys[] = "`$fieldName`";
            }
        }
        
        if (!empty($primaryKeys)) {
            $lines[] = "PRIMARY KEY (" . implode(',', $primaryKeys) . ")";
        }

        // 处理 Index 注解
        $indexAttrs = $ref->getAttributes(Index::class);
        foreach ($indexAttrs as $attr) {
            /** @var Index $idx */
            $idx = $attr->newInstance();
            $cols = is_array($idx->columns) ? $idx->columns : [$idx->columns];
            $colStr = "`" . implode("`,`", $cols) . "`";
            $keyName = $idx->name ?: $cols[0]; // 默认使用第一列名
            
            if ($idx->type === 'UNIQUE') {
                $lines[] = "UNIQUE KEY `$keyName` ($colStr)";
            } elseif ($idx->type === 'FULLTEXT') {
                $lines[] = "FULLTEXT KEY `$keyName` ($colStr)";
            } else {
                $lines[] = "KEY `$keyName` ($colStr)";
            }
        }
        
        $body = implode(",\n  ", $lines);
        $comment = $tableAttr->comment ? " COMMENT='{$tableAttr->comment}'" : "";
        
        return "CREATE TABLE `$tableName` (\n  $body\n) ENGINE={$tableAttr->engine} DEFAULT CHARSET={$tableAttr->charset}$comment";
    }

    protected function restoreData($newTable, $oldTable, array $properties)
    {
        $fields = [];
        foreach ($properties as $prop) {
            $fieldAttrs = $prop->getAttributes(Field::class);
            if (!empty($fieldAttrs)) {
                $fields[] = "`" . $prop->getName() . "`";
            }
        }
        
        if (empty($fields)) return;
        
        try {
            $oldFieldsRaw = Db::connect($this->connection)->getFields($oldTable);
            $oldFields = array_keys($oldFieldsRaw);
            
            $commonFields = [];
            foreach ($properties as $prop) {
                $name = $prop->getName();
                if (in_array($name, $oldFields)) {
                    $commonFields[] = "`$name`";
                }
            }
            
            if (empty($commonFields)) return;
            
            $commonStr = implode(',', $commonFields);
            
            $sql = "INSERT INTO `$newTable` ($commonStr) SELECT $commonStr FROM `$oldTable`";
            Db::connect($this->connection)->execute($sql);
            
        } catch (\Exception $e) {
            throw new \Exception("Data migration failed: " . $e->getMessage());
        }
    }
}