from rest_framework import serializers
from django.contrib.auth import get_user_model
from .models import DailyReport, ReportComment

User = get_user_model()


class UserSimpleSerializer(serializers.ModelSerializer):
    """用户简单信息序列化器"""
    full_name = serializers.SerializerMethodField()
    
    class Meta:
        model = User
        fields = ('id', 'username', 'full_name', 'department', 'position')
    
    def get_full_name(self, obj):
        return f'{obj.first_name} {obj.last_name}'.strip() or obj.username


class ReportCommentSerializer(serializers.ModelSerializer):
    """日报评论序列化器"""
    user = UserSimpleSerializer(read_only=True)
    
    class Meta:
        model = ReportComment
        fields = ('id', 'user', 'content', 'created_at', 'updated_at')
        read_only_fields = ('id', 'created_at', 'updated_at')
    
    def create(self, validated_data):
        validated_data['user'] = self.context['request'].user
        return super().create(validated_data)


class DailyReportListSerializer(serializers.ModelSerializer):
    """日报列表序列化器"""
    user = UserSimpleSerializer(read_only=True)
    work_summary_preview = serializers.ReadOnlyField()
    next_day_plan_preview = serializers.ReadOnlyField()
    comments_count = serializers.SerializerMethodField()
    
    class Meta:
        model = DailyReport
        fields = (
            'id', 'user', 'work_summary_preview', 'next_day_plan_preview',
            'report_date', 'created_at', 'updated_at', 'is_draft', 'comments_count'
        )
    
    def get_comments_count(self, obj):
        return obj.comments.count()


class DailyReportDetailSerializer(serializers.ModelSerializer):
    """日报详情序列化器"""
    user = UserSimpleSerializer(read_only=True)
    comments = ReportCommentSerializer(many=True, read_only=True)
    can_edit = serializers.SerializerMethodField()
    can_delete = serializers.SerializerMethodField()
    
    class Meta:
        model = DailyReport
        fields = (
            'id', 'user', 'work_summary', 'next_day_plan', 'difficulties',
            'suggestions', 'report_date', 'created_at', 'updated_at',
            'is_draft', 'comments', 'can_edit', 'can_delete'
        )
    
    def get_can_edit(self, obj):
        request = self.context.get('request')
        if not request or not request.user:
            return False
        return obj.user == request.user or request.user.is_staff
    
    def get_can_delete(self, obj):
        request = self.context.get('request')
        if not request or not request.user:
            return False
        return obj.user == request.user or request.user.is_staff


class DailyReportCreateUpdateSerializer(serializers.ModelSerializer):
    """日报创建和更新序列化器"""
    
    class Meta:
        model = DailyReport
        fields = (
            'work_summary', 'next_day_plan', 'difficulties',
            'suggestions', 'report_date', 'is_draft'
        )
    
    def validate_report_date(self, value):
        """验证日报日期"""
        request = self.context.get('request')
        if not request:
            return value
        
        # 检查是否已存在该日期的日报（更新时排除当前记录）
        queryset = DailyReport.objects.filter(
            user=request.user,
            report_date=value
        )
        
        # 如果是更新操作，排除当前记录
        if self.instance:
            queryset = queryset.exclude(id=self.instance.id)
        
        if queryset.exists():
            raise serializers.ValidationError(f'您已在 {value} 提交过日报，每天只能提交一份日报。')
        
        return value
    
    def create(self, validated_data):
        validated_data['user'] = self.context['request'].user
        return super().create(validated_data)


class DailyReportStatsSerializer(serializers.Serializer):
    """日报统计序列化器"""
    total_reports = serializers.IntegerField()
    this_month_reports = serializers.IntegerField()
    this_week_reports = serializers.IntegerField()
    draft_reports = serializers.IntegerField()
    completion_rate = serializers.FloatField()
    
    
class UserReportStatsSerializer(serializers.Serializer):
    """用户日报统计序列化器"""
    user = UserSimpleSerializer()
    total_reports = serializers.IntegerField()
    this_month_reports = serializers.IntegerField()
    last_report_date = serializers.DateField()
    completion_rate = serializers.FloatField()