<?php
namespace app\common\traits;

use support\Request;

trait FormatKvTrait
{
    /**
     * 主入口：一行把前端扁平化参数变成完整的查询配置
     *
     * @param Request $request
     * @param string  $modelClass Eloquent 模型类名
     * @return array{
     *   model: string,
     *   where: array,
     *   order: array<string,string>,
     *   fields: string[],
     *   include: string[]
     * }
     */
    protected function buildQueryConfig(Request $request, string $modelClass): array
    {
        $all = $request->all();

        return [
            'model'   => $modelClass,
            'where'   => $this->parseFilters($all),
            'order'   => $this->parseSort($all['sort'] ?? ''),
            'fields'  => $this->parseCsv($all['fields'] ?? ''),
            'include' => $this->parseCsv($all['include'] ?? ''),
        ];
    }

    /**
     * 把除 sort/fields/include/page/limit 以外的所有参数
     * 智能转换为 where 条件
     *
     * 支持：
     * - 等值：foo=bar
     * - NOT：foo=!bar 或 foo=!bar1,bar2
     * - 范围：foo=2025-07-01,2025-07-15 → between
     * - 列表：foo=a,b,c → in
     * - NULL：foo=null
     * - NOT NULL：foo=!null
     * - 通配符：foo=xia* → like 'xia%'
     *
     * 关联字段直接写 relation.field=xxx
     */
    protected function parseFilters(array $params): array
    {
        $where    = [];
        $reserved = ['sort','fields','include','page','limit'];

        foreach ($params as $key => $val) {
            if (in_array($key, $reserved, true)) {
                continue;
            }
            // NULL / NOT NULL
            if ($val === 'null') {
                $where[$key] = ['is null'];
                continue;
            }
            if ($val === '!null') {
                $where[$key] = ['is not null'];
                continue;
            }
            // NOT equal or NOT IN
            if (str_starts_with($val, '!')) {
                $v = substr($val, 1);
                if (str_contains($v, ',')) {
                    $list = array_map('trim', explode(',', $v));
                    $where[$key] = ['not in', $list];
                } else {
                    $where[$key] = ['<>', $this->cast($v)];
                }
                continue;
            }
            // BETWEEN or IN
            if (str_contains($val, ',')) {
                $parts = array_map('trim', explode(',', $val));
                if (count($parts) === 2 && $this->isRangeValue($parts[0], $parts[1])) {
                    $where[$key] = ['between', $parts];
                } else {
                    $where[$key] = ['in', $this->castArray($parts)];
                }
                continue;
            }
            // LIKE
            if (str_contains($val, '*') || str_contains($val, '%')) {
                $pattern = str_replace('*', '%', $val);
                $where[$key] = ['like', $pattern];
                continue;
            }
            // 默认 EQ
            $where[$key] = $this->cast($val);
        }

        return $where;
    }

    /**
     * 解析 sort=id,-created_at → ['id'=>'asc','created_at'=>'desc']
     */
    protected function parseSort(string $sort): array
    {
        $order = [];
        foreach (explode(',', $sort) as $piece) {
            $f = trim($piece);
            if ($f === '') {
                continue;
            }
            if ($f[0] === '-') {
                $order[substr($f, 1)] = 'desc';
            } else {
                $order[$f] = 'asc';
            }
        }
        return $order;
    }

    /**
     * 逗号分割成数组
     */
    protected function parseCsv(string $csv): array
    {
        if ($csv === '') {
            return [];
        }
        return array_filter(array_map('trim', explode(',', $csv)));
    }

    /** 简单类型转换：全数字→int/float，其余保留原字符串 */
    protected function cast(string $v): mixed
    {
        if (is_numeric($v)) {
            return strpos($v, '.') !== false ? (float)$v : (int)$v;
        }
        return $v;
    }

    /** 批量类型转换 */
    protected function castArray(array $arr): array
    {
        return array_map(fn($v) => $this->cast($v), $arr);
    }

    /** 判断两端是否可做 BETWEEN（数字或 YYYY-MM-DD 日期） */
    protected function isRangeValue(string $a, string $b): bool
    {
        return (is_numeric($a) && is_numeric($b))
            || (preg_match('/^\d{4}-\d{2}-\d{2}$/', $a)
                && preg_match('/^\d{4}-\d{2}-\d{2}$/', $b));
    }
}