<?php

namespace app\common\utils;

use support\Db;

class TableInspector
{
    /**
     * 获取某个表的所有字段信息
     */
    public static function getColumns(string $table, ?string $database = null): array
    {
        $database = $database ?: Db::connection()->getDatabaseName();

        $columns = Db::select("
            SELECT COLUMN_NAME, DATA_TYPE, COLUMN_TYPE, IS_NULLABLE,
                   COLUMN_DEFAULT, COLUMN_COMMENT, EXTRA
            FROM information_schema.COLUMNS
            WHERE TABLE_SCHEMA = ? AND TABLE_NAME = ?
            ORDER BY ORDINAL_POSITION
        ", [$database, $table]);

        return array_map(function ($col) {
            return [
                'name'        => $col->COLUMN_NAME,
                'type'        => $col->DATA_TYPE,
                'column_type' => $col->COLUMN_TYPE,
                'nullable'    => $col->IS_NULLABLE === 'YES',
                'default'     => $col->COLUMN_DEFAULT,
                'comment'     => $col->COLUMN_COMMENT,
                'extra'       => $col->EXTRA,
            ];
        }, $columns);
    }

    /**
     * 获取字段名列表
     */
    public static function getColumnNames(string $table, ?string $database = null): array
    {
        return array_column(self::getColumns($table, $database), 'name');
    }

    /**
     * 获取字段注释 map：字段名 => 注释
     */
    public static function getColumnComments(string $table, ?string $database = null): array
    {
        $columns = self::getColumns($table, $database);
        $map = [];
        foreach ($columns as $col) {
            $map[$col['name']] = $col['comment'];
        }
        return $map;
    }
}