from rest_framework import serializers
from .models import (
    Homework, HomeworkExerciseItem, HomeworkAssignment, 
    HomeworkAssignmentItem, HomeworkStatus,
    TrainingHomeworkAssignment, TrainingHomeworkExerciseItem
)


class HomeworkExerciseItemSerializer(serializers.ModelSerializer):
    exercise_name = serializers.CharField(source='exercise.name', read_only=True)
    exercise_category = serializers.CharField(source='exercise.category', read_only=True)

    class Meta:
        model = HomeworkExerciseItem
        fields = ['id', 'exercise', 'exercise_name', 'exercise_category', 'reps', 'time_minutes', 'order']


class HomeworkSerializer(serializers.ModelSerializer):
    exercise_items = HomeworkExerciseItemSerializer(many=True, read_only=True)
    club_name = serializers.CharField(source='club.name', read_only=True)
    exercise_count = serializers.IntegerField(source='exercise_items.count', read_only=True)

    class Meta:
        model = Homework
        fields = ['id', 'title', 'description', 'club', 'club_name', 'due_date', 'is_active', 
                  'exercise_items', 'exercise_count', 'created_at', 'updated_at']


class HomeworkDetailSerializer(HomeworkSerializer):
    exercise_items = HomeworkExerciseItemSerializer(many=True, read_only=True)

    class Meta(HomeworkSerializer.Meta):
        fields = HomeworkSerializer.Meta.fields


class HomeworkAssignmentItemSerializer(serializers.ModelSerializer):
    exercise_name = serializers.CharField(source='exercise.name', read_only=True)
    exercise_category = serializers.CharField(source='exercise.category', read_only=True)

    class Meta:
        model = HomeworkAssignmentItem
        fields = ['id', 'exercise', 'exercise_name', 'exercise_category', 'is_completed', 'completion_date']


class HomeworkAssignmentSerializer(serializers.ModelSerializer):
    homework_title = serializers.CharField(source='homework.title', read_only=True)
    club_name = serializers.CharField(source='club.name', read_only=True)
    wrestler_name = serializers.SerializerMethodField()
    completed_items = serializers.SerializerMethodField()
    total_items = serializers.SerializerMethodField()
    items = HomeworkAssignmentItemSerializer(many=True, read_only=True)

    class Meta:
        model = HomeworkAssignment
        fields = ['id', 'homework', 'homework_title', 'wrestler', 'wrestler_name', 'club', 'club_name',
                   'due_date', 'notes', 'is_completed', 'completion_date', 'completed_items', 
                   'total_items', 'items', 'created_at']

    def get_wrestler_name(self, obj):
        return f"{obj.wrestler.first_name} {obj.wrestler.last_name}"

    def get_completed_items(self, obj):
        return obj.items.filter(is_completed=True).count()

    def get_total_items(self, obj):
        return obj.items.count()


class HomeworkAssignmentListSerializer(serializers.ModelSerializer):
    homework_title = serializers.CharField(source='homework.title', read_only=True)
    club_name = serializers.CharField(source='club.name', read_only=True)
    wrestler_name = serializers.SerializerMethodField()

    class Meta:
        model = HomeworkAssignment
        fields = ['id', 'homework', 'homework_title', 'wrestler', 'wrestler_name', 'club', 'club_name',
                   'due_date', 'notes', 'is_completed', 'completion_date', 'created_at']

    def get_wrestler_name(self, obj):
        return f"{obj.wrestler.first_name} {obj.wrestler.last_name}"


class AssignHomeworkSerializer(serializers.Serializer):
    homework = serializers.IntegerField()
    wrestlers = serializers.ListField(child=serializers.IntegerField())
    due_date = serializers.DateField(required=False, allow_null=True)
    notes = serializers.CharField(required=False, allow_blank=True, default='')


class CompleteItemSerializer(serializers.Serializer):
    item_id = serializers.IntegerField()


class HomeworkStatusSerializer(serializers.ModelSerializer):
    wrestler_name = serializers.CharField(source='wrestler.__str__', read_only=True)

    class Meta:
        model = HomeworkStatus
        fields = '__all__'


# NEUES SYSTEM: Training-basierte Homework

class TrainingHomeworkExerciseItemSerializer(serializers.ModelSerializer):
    exercise_name = serializers.CharField(source='exercise.name', read_only=True)
    exercise_category = serializers.CharField(source='exercise.category', read_only=True)

    class Meta:
        model = TrainingHomeworkExerciseItem
        fields = ['id', 'exercise', 'exercise_name', 'exercise_category', 'reps', 'time_minutes', 'order', 'is_completed']


class TrainingHomeworkAssignmentSerializer(serializers.ModelSerializer):
    exercises = serializers.SerializerMethodField()
    training_date = serializers.DateField(source='training.date', read_only=True)
    training_group = serializers.CharField(source='training.group', read_only=True)
    wrestler_name = serializers.SerializerMethodField()
    wrestler_group = serializers.CharField(source='wrestler.group', read_only=True)

    class Meta:
        model = TrainingHomeworkAssignment
        fields = ['id', 'training', 'training_date', 'training_group', 'wrestler', 'wrestler_name', 
                   'wrestler_group', 'notes', 'is_completed', 'completion_date', 'exercises', 'created_at']

    def get_wrestler_name(self, obj):
        return f"{obj.wrestler.first_name} {obj.wrestler.last_name}"

    def get_exercises(self, obj):
        exercises = obj.exercises.all().order_by('order')
        return TrainingHomeworkExerciseItemSerializer(exercises, many=True).data


class TrainingHomeworkAssignmentCreateSerializer(serializers.Serializer):
    training = serializers.IntegerField()
    wrestler = serializers.IntegerField()
    exercises = serializers.ListField(
        child=serializers.DictField(child=serializers.IntegerField(allow_null=True))
    )
    notes = serializers.CharField(required=False, allow_blank=True, default='')

    def create(self, validated_data):
        from utils.permissions import get_user_club
        from exercises.models import Exercise
        from trainings.models import Training
        from wrestlers.models import Wrestler

        user = self.context['request'].user
        club = get_user_club(user)

        training_id = validated_data['training']
        wrestler_id = validated_data['wrestler']
        exercises_data = validated_data['exercises']
        notes = validated_data.get('notes', '')

        try:
            training_obj = Training.objects.get(id=training_id)
        except Training.DoesNotExist:
            raise serializers.ValidationError({'training': f'Training with id {training_id} does not exist'})

        try:
            wrestler_obj = Wrestler.objects.get(id=wrestler_id)
        except Wrestler.DoesNotExist:
            raise serializers.ValidationError({'wrestler': f'Wrestler with id {wrestler_id} does not exist'})

        # Create assignment
        assignment = TrainingHomeworkAssignment.objects.create(
            training=training_obj,
            wrestler=wrestler_obj,
            club=club,
            notes=notes
        )

        # Create individual exercises for this assignment
        for i, ex in enumerate(exercises_data):
            try:
                exercise_obj = Exercise.objects.get(id=ex['exercise'])
                TrainingHomeworkExerciseItem.objects.create(
                    assignment=assignment,
                    exercise=exercise_obj,
                    reps=ex.get('reps'),
                    time_minutes=ex.get('time_minutes'),
                    order=i
                )
            except Exercise.DoesNotExist:
                pass

        return assignment

    def to_representation(self, instance):
        return TrainingHomeworkAssignmentSerializer(instance, context=self.context).data