map-dots/run/server.go

package run

import (
	"errors"
	"fmt"
	"image/png"
	"net/http"
	"net/url"
	"strconv"
	"time"

	"git.fjla.uk/fred.boniface/map-dots/imaging"
	"git.fjla.uk/fred.boniface/map-dots/log"
	"git.fjla.uk/fred.boniface/map-dots/traccar"
	"go.uber.org/zap"
)

func Server() {

	http.HandleFunc("/traccar/", handleTraccarRequest)
	http.HandleFunc("/help/", handleHelpRequest)

	serverAddr := ":8198" // Set your desired server address
	fmt.Printf("Starting server on http://%s\n", serverAddr)
	log.Msg.Info("Starting server  on http://" + serverAddr)
	err := http.ListenAndServe(serverAddr, nil)
	if err != nil {
		fmt.Printf("Error starting server: %s\n", err)
		log.Msg.Error("Server failed to start:" + err.Error())
	}
}

func handleTraccarRequest(w http.ResponseWriter, r *http.Request) {
	queryValues := r.URL.Query()

	id, from, to, height, width, style, format, err := validateAndProcessParams(queryValues)
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	log.Msg.Debug("Requesting Data from Traccar",
		zap.String("id", id),
		zap.Time("from", from),
		zap.Time("to", to),
	)

	locations, err := traccar.GetPositions(id, from, to)
	if err != nil {
		fmt.Println("Error fetching data: " + err.Error())
		log.Msg.Error("Error fetching traccar data",
			zap.String("id", id),
			zap.Time("from", from),
			zap.Time("to", to),
			zap.Error(err),
		)
	} else {
		log.Msg.Debug("Position data fetched")
	}

	img := imaging.Generate(height, width, style, locations)

	fmt.Printf("Requested format, %s, returning PNG as only supported format", format)

	switch format {
	case "png":
		w.Header().Set("Content-Type", "image/png")
		err = png.Encode(w, img)
		if err != nil {
			http.Error(w, "Error encoding image", http.StatusInternalServerError)
			return
		}
	default:
		w.Header().Set("Content-Type", "text/plain")
		w.Write([]byte("Unsupported format, only 'PNG' is supported at present"))
	}
}

func validateAndProcessParams(queryValues url.Values) (string, time.Time, time.Time, int, int, string, string, error) {
	// Validate and process individual parameters
	id := queryValues.Get("id")
	if id == "" {
		return "", time.Time{}, time.Time{}, 0, 0, "", "", errors.New("missing required parameter 'id'")
	}

	fromStr := queryValues.Get("from")
	toStr := queryValues.Get("to")
	heightStr := queryValues.Get("height")
	widthStr := queryValues.Get("width")
	style := queryValues.Get("style")
	format := queryValues.Get("format")

	// Apply defaults if parameters are not specified
	if fromStr == "" {
		thirtyDaysAgo := time.Now().AddDate(0, 0, -30)
		fromStr = thirtyDaysAgo.UTC().Format(time.RFC3339)
	}
	if toStr == "" {
		toStr = time.Now().UTC().Format(time.RFC3339)
	}
	if heightStr == "" {
		heightStr = "1080"
	}
	if widthStr == "" {
		widthStr = "1920"
	}
	if style == "" {
		style = "circle"
	}
	if format == "" {
		format = "png"
	}

	// VALIDATE HEIGHT/WIDTH
	// Convert height and width to integers
	height, errHeight := strconv.Atoi(heightStr)
	width, errWidth := strconv.Atoi(widthStr)
	if errHeight != nil || errWidth != nil {
		return "", time.Time{}, time.Time{}, 0, 0, "", "", errors.New("invalid height or width")
	}
	if height >= 7680 {
		return "", time.Time{}, time.Time{}, 0, 0, "", "", errors.New("invalid height, max: 7680")
	}
	if width >= 4320 {
		return "", time.Time{}, time.Time{}, 0, 0, "", "", errors.New("invalid width, max: 4320")
	}

	// VALIDATE FROM/TO
	// Parse the ISO date strings to time.Time objects
	from, errFrom := time.Parse(time.RFC3339, fromStr)
	to, errTo := time.Parse(time.RFC3339, toStr)
	if errFrom != nil || errTo != nil {
		return "", time.Time{}, time.Time{}, 0, 0, "", "", errors.New("invalid date format")
	}

	// Define the maximum allowable time duration (e.g., 90 days)
	maxAllowableDuration := time.Hour * 24 * 90

	// Calculate the duration between from and to
	duration := to.Sub(from)
	if duration > maxAllowableDuration {
		return "", time.Time{}, time.Time{}, 0, 0, "", "", errors.New("date range is too wide, max: 90d")
	}
	// ... Validate other parameters as needed

	return id, from, to, height, width, style, format, nil
}

func handleHelpRequest(w http.ResponseWriter, r *http.Request) {
	helpText := `
API Usage Information:

Endpoint: /traccar/:id
Parameters:
  - id: Traccar device ID
  - from: Start date in ISO format (90-days or less after 'to')
  - to: End date in ISO format
  - height: Output image height (1-7680)
  - width: Output image width (1-4320)
  - style: Output image style (circles)
  - format: Output image format (png, jpeg, gif, bmp, tiff, webp)

Example: /traccar/?id=1&from=2023-01-01T00:00:00Z&to=2023-02-01T00:00:00Z&height=600&width=800&style=circle&format=png
`

	w.Header().Set("Content-Type", "text/plain")
	fmt.Fprint(w, helpText)
}