package main

import (
	"database/sql"
	"fmt"
	"log"
	"net/http"
	"os"

	"github.com/gin-gonic/gin"
	"github.com/golang-migrate/migrate/v4"
	"github.com/golang-migrate/migrate/v4/database/postgres"
	_ "github.com/golang-migrate/migrate/v4/source/file"
	_ "github.com/lib/pq"
)

var db *sql.DB

func initDB() {
	var err error
	connStr := os.Getenv("DATABASE_URL")
	if connStr == "" {
		connStr = "host=localhost port=5432 user=apiserver password=apiserver dbname=apiserver sslmode=disable"
	}

	db, err = sql.Open("postgres", connStr)
	if err != nil {
		log.Fatal("Failed to connect to database:", err)
	}

	if err = db.Ping(); err != nil {
		log.Fatal("Failed to ping database:", err)
	}

	fmt.Println("Database connected successfully!")
}

func runMigrations() {
	driver, err := postgres.WithInstance(db, &postgres.Config{})
	if err != nil {
		log.Fatal("Failed to create migration driver:", err)
	}

	m, err := migrate.NewWithDatabaseInstance(
		"file://migrations",
		"postgres", driver)
	if err != nil {
		log.Fatal("Failed to create migrate instance:", err)
	}

	if err := m.Up(); err != nil && err != migrate.ErrNoChange {
		log.Fatal("Failed to run migrations:", err)
	}

	fmt.Println("Migrations completed successfully!")
}

type User struct {
	ID        int    `json:"id"`
	Name      string `json:"name"`
	Email     string `json:"email"`
	CreatedAt string `json:"created_at"`
	UpdatedAt string `json:"updated_at"`
}

func helloWorld(c *gin.Context) {
	rows, err := db.Query("SELECT id, name, email, created_at, updated_at FROM users")
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{
			"error": err.Error(),
		})
		return
	}
	defer rows.Close()

	var users []User
	for rows.Next() {
		var user User
		err := rows.Scan(&user.ID, &user.Name, &user.Email, &user.CreatedAt, &user.UpdatedAt)
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{
				"error": err.Error(),
			})
			return
		}
		users = append(users, user)
	}

	c.JSON(http.StatusOK, gin.H{
		"message": "Hello from PostgreSQL!",
		"users":   users,
	})
}

func main() {
	initDB()
	defer db.Close()

	if os.Getenv("AUTO_MIGRATE") == "true" {
		runMigrations()
	}

	r := gin.Default()

	r.GET("/hello", helloWorld)

	port := os.Getenv("PORT")
	if port == "" {
		port = "8080"
	}

	fmt.Printf("Server starting on port %s...\n", port)
	if err := r.Run(":" + port); err != nil {
		log.Fatal("Failed to start server:", err)
	}
}