package services

import (
	"database/sql"
	"fmt"
	_ "github.com/lib/pq"
	"go-weather/models"
	"time"
)

func ConnectDB(connStr string) (*sql.DB, error) {
	db, err := sql.Open("postgres", connStr)
	if err != nil {
		return nil, fmt.Errorf("failed to connect to db: %v", err)
	}

	err = db.Ping()
	if err != nil {
		return nil, fmt.Errorf("failed to connect to db: %v", err)
	}

	fmt.Println("connected to PostgreSQL")
	return db, nil
}

type DatabaseService struct {
	db *sql.DB
}

func NewDatabaseService(db *sql.DB) *DatabaseService {
	return &DatabaseService{db: db}
}

func (s *DatabaseService) CreateTable() error {
	_, err := s.db.Exec(`
		CREATE TABLE IF NOT EXISTS weather_readings (
			id SERIAL PRIMARY KEY,
			city TEXT NOT NULL,
			temp DOUBLE PRECISION NOT NULL,
			feels_like DOUBLE PRECISION NOT NULL,
			humidity INTEGER NOT NULL,
			conditions TEXT NOT NULL,
			fetched_at TIMESTAMP WITH TIME ZONE NOT NULL
		)
	`)

	if err != nil {
		fmt.Errorf("failed to create table: %v", err)
	}
	fmt.Println("weather_readings table ready")
	return nil
}

func (s *DatabaseService) SaveReading(weather models.WeatherResponse) (int, error) {
	conditions := ""
	if len(weather.Weather) > 0 {
		conditions = weather.Weather[0].Description
	}

	var id int
	err := s.db.QueryRow(
		`INSERT INTO weather_readings (city, temp, feels_like, humidity, conditions, fetched_at)
		VALUES ($1, $2, $3, $4, $5, $6)
		RETURNING id`,
		weather.Name,
		weather.Main.Temp,
		weather.Main.FeelsLike,
		weather.Main.Humidity,
		conditions,
		time.Now(),
	).Scan(&id)
	if err != nil {
		return 0, fmt.Errorf("failed to save reading: %w", err)
	}
	return id, nil
}

func (s *DatabaseService) GetReadings(city string, limit int) ([]models.Reading, error) {
	rows, err := s.db.Query(
		`SELECT id, city, temp, feels_like, humidity, conditions, fetched_at
		 FROM weather_readings
		 WHERE city ILIKE $1
		 ORDER BY fetched_at DESC
		 LIMIT $2`,
		city, limit,
	)

	if err != nil {
		return nil, fmt.Errorf("Query failed: %w", err)
	}
	defer rows.Close()

	var readings []models.Reading
	for rows.Next() {
		var r models.Reading
		err := rows.Scan(&r.ID, &r.City, &r.Temp, &r.FeelsLike, &r.Humidity, &r.Conditions, &r.FetchedAt)

		if err != nil {
			return nil, fmt.Errorf("scan failed: %w", err)
		}

		readings = append(readings, r)
	}
	return readings, nil
}