<?php

namespace App\Services\Teachers;

use App\Models\Teachers\TeacherClass;
use App\Services\BaseService;
use Illuminate\Pagination\LengthAwarePaginator;

/**
 * 老师班级关联服务类
 */
class TeacherClassService extends BaseService
{
    protected string $modelClass = TeacherClass::class;

    /**
     * 获取老师班级关联列表
     */
    public function getList(array $params): LengthAwarePaginator
    {
        $query = TeacherClass::query();

        // 老师ID筛选
        if (!empty($params['teacher_id'])) {
            $query->where('teacher_id', $params['teacher_id']);
        }

        // 学校筛选
        if (!empty($params['school_id'])) {
            $query->where('school_id', $params['school_id']);
        }

        // 班级筛选
        if (!empty($params['class_id'])) {
            $query->where('class_id', $params['class_id']);
        }

        // 年级筛选
        if (!empty($params['grade_id'])) {
            $query->where('grade_id', $params['grade_id']);
        }

        // 班主任筛选
        if (isset($params['headman'])) {
            $query->where('headman', $params['headman']);
        }

        // 包含关联信息
        $query->with([
            'teacher:id,username,nickname',
            'school:id,name,alias',
            'schoolClass:id,name,code,campus_id,grade_id,number'
        ]);

        // 排序
        $query->orderBy('school_id', 'asc')
              ->orderBy('grade_id', 'asc')
              ->orderBy('class_id', 'asc')
              ->orderBy('headman', 'desc');

        return $query->paginate($params['page_size'] ?? 15);
    }

    /**
     * 获取老师的班级列表
     */
    public function getTeacherClasses(int $teacherId): array
    {
        return TeacherClass::where('teacher_id', $teacherId)
            ->with([
                'school:id,name,alias',
                'schoolClass:id,name,code,campus_id,grade_id,number'
            ])
            ->get()
            ->toArray();
    }

    /**
     * 获取班级的老师列表
     */
    public function getClassTeachers(int $classId): array
    {
        return TeacherClass::where('class_id', $classId)
            ->with([
                'teacher:id,username,nickname',
                'school:id,name,alias'
            ])
            ->get()
            ->toArray();
    }

    /**
     * 获取学校的老师列表
     */
    public function getSchoolTeachers(int $schoolId): array
    {
        return TeacherClass::where('school_id', $schoolId)
            ->with([
                'teacher:id,username,nickname',
                'schoolClass:id,name,code,campus_id,grade_id,number'
            ])
            ->get()
            ->toArray();
    }

    /**
     * 获取班主任列表
     */
    public function getHeadmans(?int $schoolId = null, ?int $gradeId = null): array
    {
        $query = TeacherClass::headman();

        if ($schoolId) {
            $query->where('school_id', $schoolId);
        }

        if ($gradeId) {
            $query->where('grade_id', $gradeId);
        }

        return $query->with([
            'teacher:id,username,nickname',
            'school:id,name,alias',
            'schoolClass:id,name,code,campus_id,grade_id,number'
        ])->get()->toArray();
    }

    /**
     * 批量分配老师到班级
     */
    public function batchAssignTeachersToClass(array $teacherIds, int $classId, ?int $gradeId = null): array
    {
        $class = \App\Models\Schools\SchoolClass::findOrFail($classId);
        $results = [];

        foreach ($teacherIds as $teacherId) {
            // 检查是否已经存在关联
            $exists = TeacherClass::where('teacher_id', $teacherId)
                ->where('class_id', $classId)
                ->exists();

            if (!$exists) {
                $data = [
                    'teacher_id' => $teacherId,
                    'school_id' => $class->school_id,
                    'grade_id' => $gradeId ?? $class->grade_id,
                    'class_id' => $classId,
                    'headman' => 0,
                ];

                $result = $this->create($data);
                $results[] = $result;
            }
        }

        return $results;
    }

    /**
     * 批量移除老师班级关联
     */
    public function batchRemoveTeachersFromClass(array $teacherIds, int $classId): int
    {
        return TeacherClass::whereIn('teacher_id', $teacherIds)
            ->where('class_id', $classId)
            ->delete();
    }

    /**
     * 设置班主任
     */
    public function setHeadman(int $teacherId, int $classId): bool
    {
        // 先清除该班级的所有班主任
        TeacherClass::where('class_id', $classId)->update(['headman' => 0]);

        // 设置新的班主任
        $teacherClass = TeacherClass::where('teacher_id', $teacherId)
            ->where('class_id', $classId)
            ->first();

        if (!$teacherClass) {
            throw new \InvalidArgumentException('该老师不在此班级中');
        }

        $teacherClass->headman = 1;
        return $teacherClass->save();
    }

    /**
     * 取消班主任
     */
    public function removeHeadman(int $classId): bool
    {
        return TeacherClass::where('class_id', $classId)
            ->update(['headman' => 0]) > 0;
    }

    /**
     * 获取老师班级统计信息
     */
    public function getTeacherClassStats(int $teacherId): array
    {
        $classes = TeacherClass::where('teacher_id', $teacherId)
            ->with(['school:id,name', 'schoolClass:id,name'])
            ->get();

        return [
            'total_classes' => $classes->count(),
            'headman_classes' => $classes->where('headman', 1)->count(),
            'schools' => $classes->pluck('school')->unique('id')->values()->toArray(),
            'classes' => $classes->pluck('schoolClass')->toArray(),
        ];
    }

    /**
     * 创建前的特殊处理
     */
    protected function beforeCreate(array &$data): void
    {
        // 设置默认值
        $data['headman'] = $data['headman'] ?? 0;

        // 验证老师是否存在
        if (!empty($data['teacher_id'])) {
            $teacher = \App\Models\User::find($data['teacher_id']);
            if (!$teacher) {
                throw new \InvalidArgumentException('指定的老师不存在');
            }
        }

        // 验证学校是否存在
        if (!empty($data['school_id'])) {
            $school = \App\Models\Schools\School::find($data['school_id']);
            if (!$school) {
                throw new \InvalidArgumentException('指定的学校不存在');
            }
        }

        // 验证班级是否存在
        if (!empty($data['class_id'])) {
            $class = \App\Models\Schools\SchoolClass::find($data['class_id']);
            if (!$class) {
                throw new \InvalidArgumentException('指定的班级不存在');
            }

            // 验证班级是否属于指定学校
            if (isset($data['school_id']) && $class->school_id !== $data['school_id']) {
                throw new \InvalidArgumentException('指定的班级不属于该学校');
            }
        }

        // 检查是否已经存在关联
        $exists = TeacherClass::where('teacher_id', $data['teacher_id'])
            ->where('class_id', $data['class_id'])
            ->exists();

        if ($exists) {
            throw new \InvalidArgumentException('该老师已经在此班级中');
        }
    }
}