from models import db, Assessment, Exercise, GradingElement
from utils import safe_int_conversion, safe_decimal_conversion, validate_json_data, ValidationError, log_user_action
from datetime import datetime
from decimal import Decimal

class AssessmentService:
    """Service pour gérer les opérations sur les évaluations"""
    
    @staticmethod
    def create_assessment(form_data):
        """Crée une nouvelle évaluation"""
        assessment = Assessment(
            title=form_data['title'],
            description=form_data.get('description', ''),
            date=form_data['date'],
            trimester=form_data['trimester'],
            class_group_id=form_data['class_group_id'],
            coefficient=form_data['coefficient']
        )
        db.session.add(assessment)
        db.session.flush()  # Pour obtenir l'ID
        log_user_action("Création évaluation", f"ID: {assessment.id}, Titre: {assessment.title}")
        return assessment
    
    @staticmethod
    def update_assessment_basic_info(assessment, form_data):
        """Met à jour les informations de base d'une évaluation"""
        assessment.title = form_data['title']
        assessment.description = form_data.get('description', '')
        assessment.date = form_data['date']
        assessment.trimester = form_data['trimester']
        assessment.class_group_id = form_data['class_group_id']
        assessment.coefficient = form_data['coefficient']
        log_user_action("Modification évaluation", f"ID: {assessment.id}")
    
    @staticmethod
    def delete_assessment_exercises(assessment):
        """Supprime tous les exercices d'une évaluation (pour remplacement)"""
        for exercise in assessment.exercises:
            db.session.delete(exercise)
    
    @staticmethod
    def process_assessment_with_exercises(assessment_data, is_edit=False, existing_assessment=None):
        """Traite une évaluation complète avec exercices et éléments"""
        # Validation des données de base
        required_fields = ['title', 'date', 'trimester', 'class_group_id', 'coefficient']
        validate_json_data(assessment_data, required_fields)
        
        # Validation et conversion des types
        try:
            class_group_id = safe_int_conversion(assessment_data['class_group_id'], "ID de classe")
            coefficient = safe_decimal_conversion(assessment_data['coefficient'], "coefficient")
            trimester = safe_int_conversion(assessment_data['trimester'], "trimestre")
            
            # Validation du trimestre
            if trimester not in [1, 2, 3]:
                raise ValidationError("Le trimestre doit être 1, 2 ou 3")
            
            # Validation de la date
            date_str = assessment_data.get('date')
            if date_str:
                date_obj = datetime.strptime(date_str, '%Y-%m-%d').date()
            else:
                raise ValidationError("Date requise")
                
        except ValueError as e:
            raise ValidationError(str(e))
        
        # Préparation des données validées
        validated_data = {
            'title': assessment_data['title'].strip(),
            'description': assessment_data.get('description', '').strip(),
            'date': date_obj,
            'trimester': trimester,
            'class_group_id': class_group_id,
            'coefficient': coefficient
        }
        
        # Création ou mise à jour de l'évaluation
        if is_edit and existing_assessment:
            AssessmentService.update_assessment_basic_info(existing_assessment, validated_data)
            AssessmentService.delete_assessment_exercises(existing_assessment)
            assessment = existing_assessment
        else:
            assessment = AssessmentService.create_assessment(validated_data)
        
        # Traitement des exercices
        exercises_data = assessment_data.get('exercises', [])
        AssessmentService.process_exercises(assessment, exercises_data)
        
        return assessment
    
    @staticmethod
    def process_exercises(assessment, exercises_data):
        """Traite les exercices d'une évaluation"""
        for ex_data in exercises_data:
            # Validation des données d'exercice
            if not ex_data.get('title'):
                raise ValidationError("Titre d'exercice requis")
            
            try:
                order = safe_int_conversion(ex_data.get('order', 1), "ordre de l'exercice")
                if order < 1:
                    raise ValidationError("L'ordre de l'exercice doit être positif")
            except ValueError as e:
                raise ValidationError(str(e))
            
            exercise = Exercise(
                title=ex_data['title'].strip(),
                description=ex_data.get('description', '').strip(),
                order=order,
                assessment_id=assessment.id
            )
            db.session.add(exercise)
            db.session.flush()
            
            # Traitement des éléments de notation
            grading_elements_data = ex_data.get('grading_elements', [])
            AssessmentService.process_grading_elements(exercise, grading_elements_data)
    
    @staticmethod
    def process_grading_elements(exercise, grading_elements_data):
        """Traite les éléments de notation d'un exercice"""
        for elem_data in grading_elements_data:
            # Validation des données d'élément
            if not elem_data.get('label'):
                raise ValidationError("Libellé d'élément de notation requis")
            
            grading_type = elem_data.get('grading_type', 'points')
            if grading_type not in ['points', 'score']:
                raise ValidationError("Type de notation invalide")
            
            try:
                max_points = safe_decimal_conversion(elem_data.get('max_points'), "points maximum")
                if max_points <= 0:
                    raise ValidationError("Les points maximum doivent être positifs")
            except ValueError as e:
                raise ValidationError(str(e))
            
            grading_element = GradingElement(
                label=elem_data['label'].strip(),
                description=elem_data.get('description', '').strip(),
                skill=elem_data.get('skill', '').strip(),
                max_points=max_points,
                grading_type=grading_type,
                exercise_id=exercise.id
            )
            db.session.add(grading_element)