<?php

namespace App\Service;

use App\BaseApp\BaseService;
use App\Models\AdminModel;
use App\Models\business\DepartmentModel;
use Exception;
use Psr\Container\ContainerExceptionInterface;
use Psr\Container\NotFoundExceptionInterface;

/**
 * 部门服务
 *
 * 老后台的 department/option 返回的是扁平列表，前端 BasicTree 拿到后其实渲染不出层级，
 * pid 白存了。这里 option 直接返回真正的树，账号列表左侧的部门树才能用。
 */
class DepartmentService extends BaseService
{
    public function __construct()
    {
        parent::__construct();
        $this->model = DepartmentModel::class;
        $this->selectField = ['id', 'name', 'desc', 'status', 'pid', 'color', 'created_at', 'updated_at'];
        $this->queryField = ['name' => 'like', 'status' => '=', 'pid' => '='];
        $this->orderBy = ['name' => 'id', 'sort' => 'asc'];
    }

    /**
     * 分页列表，附带每个部门的账号数
     * @throws ContainerExceptionInterface
     * @throws NotFoundExceptionInterface
     */
    public function list(): array
    {
        $result = $this->getPageList();
        $ids = array_column($result['items'] ?? [], 'id');
        $counts = $this->countAdminByDepartment($ids);
        foreach ($result['items'] as &$item) {
            $item['admin_count'] = $counts[$item['id']] ?? 0;
        }
        unset($item);
        return $result;
    }

    /**
     * 部门树（账号列表左侧筛选树、部门表单的上级选择都用这个）
     */
    public function option(): array
    {
        $rows = DepartmentModel::where('deleted_at', 0)
            ->orderBy('id')
            ->get(['id', 'name', 'pid', 'status', 'color'])
            ->toArray();
        return $this->utils->tree($rows);
    }

    /**
     * 部门树下拉（部门表单选上级用）。带 $isSelect 时首位补「顶级部门」
     */
    public function getTreeOption(bool $isSelect = false): array
    {
        $rows = DepartmentModel::where('deleted_at', 0)
            ->orderBy('id')
            ->get(['id', 'name', 'pid'])
            ->toArray();
        $result = $this->utils->tree($rows);
        if ($isSelect) {
            array_unshift($result, ['id' => 0, 'name' => '顶级部门', 'pid' => 0]);
        }
        return $result;
    }

    /**
     * @throws Exception
     */
    public function detail($id): mixed
    {
        return $this->getDetail($id);
    }

    /**
     * 新增部门
     */
    public function create($params): mixed
    {
        $this->assertNameUnique((string) ($params['name'] ?? ''), (int) ($params['pid'] ?? 0));
        return $this->insert($params);
    }

    /**
     * 编辑部门
     * @throws Exception
     */
    public function update($id, $params): mixed
    {
        $id = (int) $id;
        if (array_key_exists('name', $params)) {
            $this->assertNameUnique((string) $params['name'], (int) ($params['pid'] ?? 0), $id);
        }
        // 上级不能指向自己或自己的子孙，否则树会成环、递归建树直接栈溢出
        if (array_key_exists('pid', $params)) {
            $pid = (int) $params['pid'];
            if ($pid === $id) {
                $this->utils->errorThrow('上级部门不能是自己');
            }
            if ($pid > 0 && in_array($pid, $this->descendantIds($id), true)) {
                $this->utils->errorThrow('上级部门不能是自己的下级');
            }
        }
        return $this->save($id, $params);
    }

    /**
     * 删除部门：有子部门或仍有账号在用时拒绝，避免留下悬空引用
     * @throws Exception
     */
    public function delete($id): mixed
    {
        $ids = array_values(array_filter(array_map('intval', is_array($id) ? $id : [$id])));
        if (empty($ids)) {
            $this->utils->errorThrow('参数错误');
        }
        $hasChild = DepartmentModel::whereIn('pid', $ids)->where('deleted_at', 0)->exists();
        if ($hasChild) {
            $this->utils->errorThrow('存在下级部门，请先删除下级');
        }
        $inUse = AdminModel::whereIn('department_id', $ids)->where('deleted_at', 0)->exists();
        if ($inUse) {
            $this->utils->errorThrow('仍有账号属于该部门，请先调整账号所属部门');
        }
        return $this->del($ids);
    }

    /**
     * 停用/启用部门
     * @throws Exception
     */
    public function status($id, $status): mixed
    {
        return $this->save((int) $id, ['status' => (int) $status]);
    }

    /**
     * 同一父级下部门名不允许重复，否则树上出现两个同名节点没法分辨
     */
    private function assertNameUnique(string $name, int $pid, int $exceptId = 0): void
    {
        $name = trim($name);
        if ($name === '') {
            $this->utils->errorThrow('部门名称不能为空');
        }
        $exists = DepartmentModel::where('name', $name)
            ->where('pid', $pid)
            ->where('deleted_at', 0)
            ->when($exceptId > 0, fn ($q) => $q->where('id', '<>', $exceptId))
            ->exists();
        if ($exists) {
            $this->utils->errorThrow('同级下已存在同名部门');
        }
    }

    /**
     * 取某部门的全部子孙 id，用于成环校验
     */
    private function descendantIds(int $id): array
    {
        $all = DepartmentModel::where('deleted_at', 0)->get(['id', 'pid']);
        $childMap = [];
        foreach ($all as $row) {
            $childMap[(int) $row->pid][] = (int) $row->id;
        }
        $result = [];
        $stack = $childMap[$id] ?? [];
        while (!empty($stack)) {
            $current = array_pop($stack);
            if (in_array($current, $result, true)) {
                continue;
            }
            $result[] = $current;
            foreach ($childMap[$current] ?? [] as $child) {
                $stack[] = $child;
            }
        }
        return $result;
    }

    /**
     * 部门账号数：admin 在 mysql 连接、department 在 business 连接，跨连接不能 join，分两次查
     */
    private function countAdminByDepartment(array $departmentIds): array
    {
        if (empty($departmentIds)) {
            return [];
        }
        return AdminModel::whereIn('department_id', $departmentIds)
            ->where('deleted_at', 0)
            ->groupBy('department_id')
            ->selectRaw('department_id, COUNT(*) AS c')
            ->pluck('c', 'department_id')
            ->all();
    }
}