from rest_framework import serializers
from .models import *
from muscle.models import ExerciseMuscle
from equipment.serializers import WorkoutEquipmentSerializer

class ExerciseMuscleSerializer(serializers.ModelSerializer):
    name = serializers.SerializerMethodField()

    class Meta:
        model = ExerciseMuscle
        fields = '__all__'

    def get_name(self, obj):
        return obj.muscle.name

class ExerciseSerializer(serializers.ModelSerializer):
    muscles = serializers.SerializerMethodField()
    equipment = serializers.SerializerMethodField()
    audio_url = serializers.ReadOnlyField()
    video_url = serializers.ReadOnlyField()
    transition_url = serializers.ReadOnlyField()

    class Meta:
        model = Exercise
        fields = '__all__'

    def get_muscles(self, obj):
        # Use prefetched related manager if available (avoids N+1 queries)
        # Callers should use .prefetch_related('exercise_muscle_exercise__muscle')
        objs = obj.exercise_muscle_exercise.all()
        return ExerciseMuscleSerializer(objs, many=True).data

    def get_equipment(self, obj):
        # Use prefetched related manager if available (avoids N+1 queries)
        # Callers should use .prefetch_related('workout_exercise_workout__equipment')
        objs = obj.workout_exercise_workout.all()
        return WorkoutEquipmentSerializer(objs, many=True).data