package main

import (
	"log"
	"os"

	"github.com/gofiber/fiber/v2"

	"geoip-rest/internal/geo"
)

const (
	defaultPort   = "8080"
	defaultDBPath = "/data/GeoLite2-City.mmdb"
)

func main() {
	dbPath := env("GEOIP_DB_PATH", defaultDBPath)
	port := env("PORT", defaultPort)

	resolver, err := geo.NewResolver(dbPath)
	if err != nil {
		log.Fatalf("failed to open GeoIP database: %v", err)
	}
	defer resolver.Close()

	app := fiber.New(fiber.Config{
		DisableStartupMessage: true,
	})

	app.Get("/", func(c *fiber.Ctx) error {
		return c.JSON(fiber.Map{
			"service": "geoip-rest",
			"endpoints": []string{
				"/health",
				"/lookup?ip=<IPv4|IPv6>",
			},
		})
	})

	app.Get("/health", func(c *fiber.Ctx) error {
		return c.JSON(fiber.Map{"status": "ok"})
	})

	app.Get("/lookup", func(c *fiber.Ctx) error {
		ip := c.Query("ip")
		if ip == "" {
			ip = c.IP()
		}

		location, err := resolver.Lookup(ip)
		if err != nil {
			if err == geo.ErrInvalidIP {
				return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{
					"error": "invalid ip address",
				})
			}

			return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{
				"error": "lookup failed",
			})
		}

		return c.JSON(location)
	})

	log.Printf("starting GeoIP API on :%s using %s", port, dbPath)
	if err := app.Listen(":" + port); err != nil {
		log.Fatalf("server stopped: %v", err)
	}
}

func env(key, fallback string) string {
	if val := os.Getenv(key); val != "" {
		return val
	}
	return fallback
}