package travel

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strings"
	"time"
)

type OpenRouteClient struct {
	apiKey     string
	baseURL    string
	httpClient *http.Client
}

func (c *OpenRouteClient) HasAPIKey() bool {
	return c.apiKey != ""
}

type OpenRouteConfig struct {
	APIKey  string
	BaseURL string
}

func NewOpenRouteClient(cfg OpenRouteConfig) *OpenRouteClient {
	baseURL := cfg.BaseURL
	if baseURL == "" {
		baseURL = "https://api.openrouteservice.org"
	}

	return &OpenRouteClient{
		apiKey:  cfg.APIKey,
		baseURL: baseURL,
		httpClient: &http.Client{
			Timeout: 30 * time.Second,
		},
	}
}

func (c *OpenRouteClient) doRequest(ctx context.Context, method, path string, query url.Values) ([]byte, error) {
	fullURL := c.baseURL + path
	if len(query) > 0 {
		fullURL += "?" + query.Encode()
	}

	req, err := http.NewRequestWithContext(ctx, method, fullURL, nil)
	if err != nil {
		return nil, fmt.Errorf("create request: %w", err)
	}

	req.Header.Set("Authorization", c.apiKey)
	req.Header.Set("Accept", "application/json")

	resp, err := c.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("execute request: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("read response: %w", err)
	}

	if resp.StatusCode >= 400 {
		return nil, fmt.Errorf("API error %d: %s", resp.StatusCode, string(body))
	}

	return body, nil
}

func (c *OpenRouteClient) GetDirections(ctx context.Context, points []GeoLocation, profile string) (*RouteDirection, error) {
	if len(points) < 2 {
		return nil, fmt.Errorf("at least 2 points required")
	}

	if profile == "" {
		profile = "driving-car"
	}

	coords := make([]string, len(points))
	for i, p := range points {
		coords[i] = fmt.Sprintf("%f,%f", p.Lng, p.Lat)
	}

	query := url.Values{}
	query.Set("start", coords[0])
	query.Set("end", coords[len(coords)-1])

	body, err := c.doRequest(ctx, "GET", "/v2/directions/"+profile, query)
	if err != nil {
		return nil, err
	}

	var response struct {
		Features []struct {
			Geometry struct {
				Coordinates [][2]float64 `json:"coordinates"`
				Type        string       `json:"type"`
			} `json:"geometry"`
			Properties struct {
				Summary struct {
					Distance float64 `json:"distance"`
					Duration float64 `json:"duration"`
				} `json:"summary"`
				Segments []struct {
					Distance float64 `json:"distance"`
					Duration float64 `json:"duration"`
					Steps    []struct {
						Instruction string  `json:"instruction"`
						Distance    float64 `json:"distance"`
						Duration    float64 `json:"duration"`
						Type        int     `json:"type"`
					} `json:"steps"`
				} `json:"segments"`
			} `json:"properties"`
		} `json:"features"`
	}

	if err := json.Unmarshal(body, &response); err != nil {
		return nil, fmt.Errorf("unmarshal directions: %w", err)
	}

	if len(response.Features) == 0 {
		return nil, fmt.Errorf("no route found")
	}

	feature := response.Features[0]
	direction := &RouteDirection{
		Geometry: RouteGeometry{
			Coordinates: feature.Geometry.Coordinates,
			Type:        feature.Geometry.Type,
		},
		Distance: feature.Properties.Summary.Distance,
		Duration: feature.Properties.Summary.Duration,
	}

	for _, seg := range feature.Properties.Segments {
		for _, step := range seg.Steps {
			direction.Steps = append(direction.Steps, RouteStep{
				Instruction: step.Instruction,
				Distance:    step.Distance,
				Duration:    step.Duration,
				Type:        fmt.Sprintf("%d", step.Type),
			})
		}
	}

	return direction, nil
}

func (c *OpenRouteClient) Geocode(ctx context.Context, query string) (*GeoLocation, error) {
	params := url.Values{}
	params.Set("api_key", c.apiKey)
	params.Set("text", query)
	params.Set("size", "1")

	body, err := c.doRequest(ctx, "GET", "/geocode/search", params)
	if err != nil {
		return nil, err
	}

	var response struct {
		Features []struct {
			Geometry struct {
				Coordinates [2]float64 `json:"coordinates"`
			} `json:"geometry"`
			Properties struct {
				Name    string `json:"name"`
				Country string `json:"country"`
				Label   string `json:"label"`
			} `json:"properties"`
		} `json:"features"`
	}

	if err := json.Unmarshal(body, &response); err != nil {
		return nil, fmt.Errorf("unmarshal geocode: %w", err)
	}

	if len(response.Features) == 0 {
		return nil, fmt.Errorf("location not found: %s", query)
	}

	feature := response.Features[0]
	return &GeoLocation{
		Lng:     feature.Geometry.Coordinates[0],
		Lat:     feature.Geometry.Coordinates[1],
		Name:    feature.Properties.Name,
		Country: feature.Properties.Country,
	}, nil
}

func (c *OpenRouteClient) ReverseGeocode(ctx context.Context, lat, lng float64) (*GeoLocation, error) {
	params := url.Values{}
	params.Set("api_key", c.apiKey)
	params.Set("point.lat", fmt.Sprintf("%f", lat))
	params.Set("point.lon", fmt.Sprintf("%f", lng))
	params.Set("size", "1")

	body, err := c.doRequest(ctx, "GET", "/geocode/reverse", params)
	if err != nil {
		return nil, err
	}

	var response struct {
		Features []struct {
			Properties struct {
				Name    string `json:"name"`
				Country string `json:"country"`
				Label   string `json:"label"`
			} `json:"properties"`
		} `json:"features"`
	}

	if err := json.Unmarshal(body, &response); err != nil {
		return nil, fmt.Errorf("unmarshal reverse geocode: %w", err)
	}

	if len(response.Features) == 0 {
		return nil, fmt.Errorf("location not found at %f,%f", lat, lng)
	}

	feature := response.Features[0]
	return &GeoLocation{
		Lat:     lat,
		Lng:     lng,
		Name:    feature.Properties.Name,
		Country: feature.Properties.Country,
	}, nil
}

func (c *OpenRouteClient) SearchPOI(ctx context.Context, req POISearchRequest) ([]POI, error) {
	params := url.Values{}
	params.Set("api_key", c.apiKey)
	params.Set("request", "pois")
	params.Set("geometry", fmt.Sprintf(`{"geojson":{"type":"Point","coordinates":[%f,%f]},"buffer":%d}`, req.Lng, req.Lat, req.Radius))
	
	if len(req.Categories) > 0 {
		params.Set("filters", fmt.Sprintf(`{"category_ids":[%s]}`, strings.Join(req.Categories, ",")))
	}
	
	limit := req.Limit
	if limit == 0 {
		limit = 20
	}
	params.Set("limit", fmt.Sprintf("%d", limit))

	body, err := c.doRequest(ctx, "POST", "/pois", params)
	if err != nil {
		return nil, err
	}

	var response struct {
		Features []struct {
			Geometry struct {
				Coordinates [2]float64 `json:"coordinates"`
			} `json:"geometry"`
			Properties struct {
				OSMId    int64  `json:"osm_id"`
				Name     string `json:"osm_tags.name"`
				Category struct {
					ID   int    `json:"category_id"`
					Name string `json:"category_name"`
				} `json:"category"`
				Distance float64 `json:"distance"`
			} `json:"properties"`
		} `json:"features"`
	}

	if err := json.Unmarshal(body, &response); err != nil {
		return nil, fmt.Errorf("unmarshal POI: %w", err)
	}

	pois := make([]POI, 0, len(response.Features))
	for _, f := range response.Features {
		poi := POI{
			ID:       fmt.Sprintf("%d", f.Properties.OSMId),
			Name:     f.Properties.Name,
			Lng:      f.Geometry.Coordinates[0],
			Lat:      f.Geometry.Coordinates[1],
			Category: f.Properties.Category.Name,
			Distance: f.Properties.Distance,
		}
		pois = append(pois, poi)
	}

	return pois, nil
}

func (c *OpenRouteClient) GetIsochrone(ctx context.Context, lat, lng float64, timeMinutes int, profile string) (*RouteGeometry, error) {
	if profile == "" {
		profile = "driving-car"
	}

	params := url.Values{}
	params.Set("api_key", c.apiKey)
	params.Set("locations", fmt.Sprintf("%f,%f", lng, lat))
	params.Set("range", fmt.Sprintf("%d", timeMinutes*60))

	body, err := c.doRequest(ctx, "GET", "/v2/isochrones/"+profile, params)
	if err != nil {
		return nil, err
	}

	var response struct {
		Features []struct {
			Geometry struct {
				Coordinates [][][2]float64 `json:"coordinates"`
				Type        string         `json:"type"`
			} `json:"geometry"`
		} `json:"features"`
	}

	if err := json.Unmarshal(body, &response); err != nil {
		return nil, fmt.Errorf("unmarshal isochrone: %w", err)
	}

	if len(response.Features) == 0 {
		return nil, fmt.Errorf("no isochrone found")
	}

	coords := make([][2]float64, 0)
	if len(response.Features[0].Geometry.Coordinates) > 0 {
		coords = response.Features[0].Geometry.Coordinates[0]
	}

	return &RouteGeometry{
		Coordinates: coords,
		Type:        response.Features[0].Geometry.Type,
	}, nil
}