package services

import (
	"database/sql"
	"time"

	"github.com/rede5/gohorsejobs/backend/internal/models"
)

type FavoriteJobService struct {
	DB *sql.DB
}

func NewFavoriteJobService(db *sql.DB) *FavoriteJobService {
	return &FavoriteJobService{DB: db}
}

func (s *FavoriteJobService) AddFavorite(userID, jobID string) (*models.FavoriteJob, error) {
	query := `
		INSERT INTO favorite_jobs (user_id, job_id, created_at)
		VALUES ($1, $2, $3)
		ON CONFLICT (user_id, job_id) DO NOTHING
		RETURNING id, user_id, job_id, created_at
	`

	var favorite models.FavoriteJob
	err := s.DB.QueryRow(query, userID, jobID, time.Now()).Scan(
		&favorite.ID, &favorite.UserID, &favorite.JobID, &favorite.CreatedAt,
	)

	if err == sql.ErrNoRows {
		// Already exists, fetch it
		err = s.DB.QueryRow(
			"SELECT id, user_id, job_id, created_at FROM favorite_jobs WHERE user_id = $1 AND job_id = $2",
			userID, jobID,
		).Scan(&favorite.ID, &favorite.UserID, &favorite.JobID, &favorite.CreatedAt)
		if err != nil {
			return nil, err
		}
	} else if err != nil {
		return nil, err
	}

	return &favorite, nil
}

func (s *FavoriteJobService) RemoveFavorite(userID, jobID string) error {
	_, err := s.DB.Exec("DELETE FROM favorite_jobs WHERE user_id = $1 AND job_id = $2", userID, jobID)
	return err
}

func (s *FavoriteJobService) GetFavorites(userID string) ([]models.FavoriteJobWithDetails, error) {
	query := `
		SELECT 
			f.id, f.user_id, f.job_id, f.created_at,
			j.title, j.company_id, c.name, c.logo_url, j.location,
			j.salary_min, j.salary_max, j.salary_type
		FROM favorite_jobs f
		JOIN jobs j ON f.job_id = j.id
		JOIN companies c ON j.company_id = c.id
		WHERE f.user_id = $1
		ORDER BY f.created_at DESC
	`

	rows, err := s.DB.Query(query, userID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var favorites []models.FavoriteJobWithDetails
	for rows.Next() {
		var fav models.FavoriteJobWithDetails
		err := rows.Scan(
			&fav.ID, &fav.UserID, &fav.JobID, &fav.CreatedAt,
			&fav.JobTitle, &fav.CompanyID, &fav.CompanyName, &fav.CompanyLogoURL, &fav.Location,
			&fav.SalaryMin, &fav.SalaryMax, &fav.SalaryType,
		)
		if err != nil {
			return nil, err
		}
		favorites = append(favorites, fav)
	}

	return favorites, nil
}

func (s *FavoriteJobService) IsFavorite(userID, jobID string) (bool, error) {
	var exists bool
	err := s.DB.QueryRow(
		"SELECT EXISTS(SELECT 1 FROM favorite_jobs WHERE user_id = $1 AND job_id = $2)",
		userID, jobID,
	).Scan(&exists)
	return exists, err
}