<?php
/**
 * 渠道工具类
 * 提供渠道树形数据获取等公共方法
 */

namespace app\common\library;

use think\Db;

class ChannelUtil
{
    /**
     * 获取渠道树（一级节点，用于初始化树形选择器）
     * 
     * @return array 渠道树形数据
     */
    public static function getChannelTree()
    {
        $channelList = Db::name('nw_channel')
            ->where(['parent_id' => 0, 'status' => 1])
            ->where('id', '>', 0)
            ->field('id as value, name, level')
            ->order('id', 'asc')
            ->select();

        $tree = [];
        foreach ($channelList as $v) {
            $hasChildren = self::hasChildChannels($v['value']);
            $tree[] = [
                'name' => $v['name'],
                'value' => (int)$v['value'],
                'children' => $hasChildren ? [] : null,
            ];
        }
        return $tree;
    }

    /**
     * 获取完整渠道树（包含所有层级，用于搜索功能）
     * 
     * @return array 完整渠道树形数据
     */
    public static function getFullChannelTree()
    {
        $channelList = Db::name('nw_channel')
            ->where('status', 1)
            ->where('id', '>', 0)
            ->field('id as value, name, parent_id, level')
            ->order('id', 'asc')
            ->select();

        // 构建树形结构
        $tree = [];
        $map = [];
        foreach ($channelList as $v) {
            $item = [
                'name' => $v['name'],
                'value' => (int)$v['value'],
                'children' => [],
            ];
            $map[$v['value']] = $item;
        }

        foreach ($channelList as $v) {
            if ($v['parent_id'] == 0) {
                $tree[] = &$map[$v['value']];
            } else if (isset($map[$v['parent_id']])) {
                $map[$v['parent_id']]['children'][] = &$map[$v['value']];
            }
        }

        // 清理空的 children 数组（叶子节点设为 null）
        array_walk_recursive($tree, function(&$item) {
            // 不处理
        });
        
        // 递归清理空 children
        self::cleanEmptyChildren($tree);

        return $tree;
    }

    /**
     * 递归清理空的 children 数组
     */
    private static function cleanEmptyChildren(&$tree)
    {
        foreach ($tree as &$item) {
            if (isset($item['children'])) {
                if (empty($item['children'])) {
                    $item['children'] = null;
                } else {
                    self::cleanEmptyChildren($item['children']);
                }
            }
        }
    }

    /**
     * 获取下级渠道（用于懒加载）
     * 
     * @param int $parentId 父级渠道ID
     * @return array 下级渠道数据
     */
    public static function getChildChannels($parentId)
    {
        $parentId = intval($parentId);
        $channelList = Db::name('nw_channel')
            ->where(['parent_id' => $parentId, 'status' => 1])
            ->where('id', '>', 0)
            ->field('id as value, name, level')
            ->order('id', 'asc')
            ->select();

        $data = [];
        foreach ($channelList as $v) {
            $hasChildren = self::hasChildChannels($v['value']);
            $data[] = [
                'name' => $v['name'],
                'value' => (int)$v['value'],
                'children' => $hasChildren ? [] : null,
            ];
        }
        return $data;
    }

    /**
     * 检查是否有下级渠道
     * 
     * @param int $channelId 渠道ID
     * @return bool
     */
    public static function hasChildChannels($channelId)
    {
        return Db::name('nw_channel')
            ->where(['parent_id' => $channelId, 'status' => 1])
            ->count() > 0;
    }

    /**
     * 获取已选中渠道的详细信息（用于前端渲染 initValue）
     * 
     * @param string $channelIds 渠道ID字符串（逗号分隔或'all'）
     * @return array 已选中渠道信息
     */
    public static function getSelectedChannels($channelIds)
    {
        if (empty($channelIds) || $channelIds === 'NULL') {
            return [];
        }

        // 全选模式
        if ($channelIds === 'all') {
            $level1List = Db::name('nw_channel')
                ->where(['parent_id' => 0, 'status' => 1])
                ->field('id as value, name')
                ->order('id', 'asc')
                ->select();
            
            $result = [];
            foreach ($level1List as $v) {
                $result[] = [
                    'name' => $v['name'],
                    'value' => (int)$v['value'],
                    'selected' => true
                ];
            }
            return $result;
        }

        $ids = explode(',', $channelIds);
        $ids = array_filter(array_map('intval', $ids), function($v) { return $v > 0; });
        
        if (empty($ids)) {
            return [];
        }

        // 获取一级渠道ID列表
        $level1Ids = Db::name('nw_channel')
            ->where(['parent_id' => 0, 'status' => 1])
            ->column('id');

        // 判断是否是一级全选模式（所有一级渠道ID都在选中列表中）
        $isLevel1All = empty(array_diff($level1Ids, $ids));

        if ($isLevel1All) {
            // 一级全选模式，只返回一级渠道信息
            $level1List = Db::name('nw_channel')
                ->where(['parent_id' => 0, 'status' => 1])
                ->field('id as value, name')
                ->order('id', 'asc')
                ->select();
            
            $result = [];
            foreach ($level1List as $v) {
                $result[] = [
                    'name' => $v['name'],
                    'value' => (int)$v['value'],
                    'selected' => true
                ];
            }
            return $result;
        }

        // 部分选中模式，返回具体选中的渠道信息
        $selectedChannelList = Db::name('nw_channel')
            ->where(['id' => ['in', $ids]])
            ->field('id as value, name, parent_id')
            ->select();

        $result = [];
        foreach ($selectedChannelList as $sc) {
            $item = [
                'name' => $sc['name'],
                'value' => (int)$sc['value'],
                'selected' => true
            ];
            // 检查是否有子节点，如果有则添加 children 属性（用于树形组件识别父节点）
            if (self::hasChildChannels($sc['value'])) {
                $item['children'] = [];
            }
            $result[] = $item;
        }

        return $result;
    }
}