package service

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"time"
)

type GeocodingService interface {
    GetAddressFromCoordinates(latitude, longitude float64) (string, error)
}

type nominatimGeocoder struct {
    client *http.Client
}


func NewGeocodingService() GeocodingService {
    client := &http.Client{
        Timeout: 10 * time.Second,
    }
    return &nominatimGeocoder{
        client: client,
    }
}

type NominatimResponse struct {
	DisplayName string `json:"display_name"`
	Error 	 string `json:"error"`
}


func (g *nominatimGeocoder) GetAddressFromCoordinates(latitude, longitude float64) (string, error) {


	if latitude < -90 || latitude > 90 || longitude < -180 || longitude > 180 {
		errMsg := fmt.Sprintf("Invalid coordinates: lat=%f, lon=%f", latitude, longitude)
		return "", fmt.Errorf(errMsg)
	}

	url := fmt.Sprintf(
		"https://nominatim.openstreetmap.org/reverse?format=json&lat=%f&lon=%f&zoom=18&addressdetails=1",
		latitude, longitude,
	)


	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		log.Printf("Request creation error: %v", err)
		return "", err
	}
	req.Header.Set("User-Agent", "AssetManagementApp")

	resp, err := g.client.Do(req)
	if err != nil {
		log.Printf("HTTP request error: %v", err)
		return "", err
	}
	defer resp.Body.Close()

	// Read full response body
	bodyBytes, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		log.Printf("Error reading response body: %v", err)
		return "", err
	}


	var result NominatimResponse
	if err := json.Unmarshal(bodyBytes, &result); err != nil {
		log.Printf("JSON unmarshal error: %v", err)
		return "", err
	}

	// Detailed error checking
	if result.Error != "" {
		log.Printf("Nominatim API Error: %s", result.Error)
		return "", fmt.Errorf("geocoding error: %s", result.Error)
	}

	// Check for empty display name
	if result.DisplayName == "" {
		log.Printf("No address found for coordinates: %f, %f", latitude, longitude)
		return "", fmt.Errorf("no address found for these coordinates")
	}

	return result.DisplayName, nil
}