package repository

import (
	"context"

	"with_you/internal/model"

	"gorm.io/gorm"
)

type GradeRepository interface {
	ListByUser(userID string) ([]*model.Grade, error)
	DeleteByUser(ctx context.Context, userID string) error
	BatchCreate(ctx context.Context, grades []*model.Grade) error
	GetLatestGpaSummary(userID string) (*model.GpaSummary, error)
	SaveGpaSummary(ctx context.Context, summary *model.GpaSummary) error
	DeleteGpaSummaryByUser(ctx context.Context, userID string) error
}

type gradeRepository struct {
	db *gorm.DB
}

func NewGradeRepository(db *gorm.DB) GradeRepository {
	return &gradeRepository{db: db}
}

func (r *gradeRepository) ListByUser(userID string) ([]*model.Grade, error) {
	var grades []*model.Grade
	err := r.db.Where("user_id = ?", userID).
		Order("term DESC, created_at ASC").
		Find(&grades).Error
	return grades, err
}

func (r *gradeRepository) DeleteByUser(ctx context.Context, userID string) error {
	return r.db.WithContext(ctx).
		Where("user_id = ?", userID).
		Delete(&model.Grade{}).Error
}

func (r *gradeRepository) BatchCreate(ctx context.Context, grades []*model.Grade) error {
	return r.db.WithContext(ctx).CreateInBatches(grades, 100).Error
}

func (r *gradeRepository) GetLatestGpaSummary(userID string) (*model.GpaSummary, error) {
	var summary model.GpaSummary
	err := r.db.Where("user_id = ?", userID).
		Order("updated_at DESC").
		First(&summary).Error
	if err != nil {
		return nil, err
	}
	return &summary, nil
}

func (r *gradeRepository) SaveGpaSummary(ctx context.Context, summary *model.GpaSummary) error {
	return r.db.WithContext(ctx).Save(summary).Error
}

func (r *gradeRepository) DeleteGpaSummaryByUser(ctx context.Context, userID string) error {
	return r.db.WithContext(ctx).
		Where("user_id = ?", userID).
		Delete(&model.GpaSummary{}).Error
}