main.go

package main

import (
	"encoding/json"
	"fmt"
	"html/template"
	"io"
	"net/http"
	"strconv"
	// "net/url"
)

type Artist struct {
	ID           int      `json:"id"`
	Image        string   `json:"image"`
	Name         string   `json:"name"`
	Members      []string `json:"members"`
	CreationDate int      `json:"creationDate"`
	FirstAlbum   string   `json:"firstAlbum"`

	Relations string `json:"relations"`
}

type Relations struct {
	ID             int                 `json:"id"`
	DatesLocations map[string][]string `json:"datesLocations"`
}

type BigStruct struct {
	Artist    Artist
	Relations Relations
}

var artists1 []Artist = []Artist{}

func main() {
	http.HandleFunc("/", handleIndex)
	http.HandleFunc("/artist", handleArtist)
	http.Handle("/static/", http.StripPrefix("/static/", http.FileServer(http.Dir("static"))))
	http.ListenAndServe(":8080", nil)
	fmt.Println("Listening on port 8000... http://localhost:8080")

}

func handleIndex(w http.ResponseWriter, r *http.Request) {
	if r.URL.Path != "/" {
		ThrowError("404", w, r)
	}

	url := "https://groupietrackers.herokuapp.com/api/artists"
	artists, err := fetchArtist(url, w)
	if err != nil {
		http.Error(w, fmt.Sprintf("Error fetching artist data: %v", err), http.StatusInternalServerError)
		return
	}
	artists1 = artists
	// fmt.Println(len(artists1), "artists fetched successfully")
	executeTemp(w, "index.html", artists1)
}

func executeTemp(w http.ResponseWriter, filename string, data interface{}) {
	funcMap := template.FuncMap{
		"sub1": sub1,
		"len":  func(x []string) int { return len(x) },
	}
	temp, err := template.New(filename).Funcs(funcMap).ParseFiles(filename)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		// Avoid recursion if error.html is missing or broken
		if filename != "error.html" {
			ThrowError("500", w, nil)
		} else {
			http.Error(w, "Critical error: cannot render error page.", http.StatusInternalServerError)
		}
		return
	}
	err = temp.ExecuteTemplate(w, filename, data)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		if filename != "error.html" {
			ThrowError("500", w, nil)
		} else {
			http.Error(w, "Critical error: cannot render error page.", http.StatusInternalServerError)
		}
		return
	}
}

func fetchArtist(url string, w http.ResponseWriter) ([]Artist, error) {
	response, err := http.Get(url)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		ThrowError("500", w, nil)
	}
	defer response.Body.Close()

	if response.StatusCode != http.StatusOK {
		w.WriteHeader(http.StatusInternalServerError)
		ThrowError("500", w, nil)
	}

	body, err := io.ReadAll(response.Body)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		ThrowError("500", w, nil)
	}

	var artists []Artist
	if err := json.Unmarshal(body, &artists); err != nil {
		return nil, fmt.Errorf("JSON unmarshal error: %v", err)
	}

	return artists, nil
}

func fetchRelations(id int) (Relations, error) { //issue here
	url := fmt.Sprintf("https://groupietrackers.herokuapp.com/api/relation/%d", id)

	response, err := http.Get(url)
	if err != nil {
		return Relations{}, fmt.Errorf("HTTP request error: %v", err)
	}

	defer response.Body.Close()

	// if response.StatusCode != http.StatusOK {
	// 	return Relations{}, fmt.Errorf("HTTP status code: %d", response.StatusCode)
	// }

	body, err := io.ReadAll(response.Body)
	if err != nil {
		return Relations{}, err
	}

	var rel Relations
	if err := json.Unmarshal(body, &rel); err != nil {
		return Relations{}, fmt.Errorf("JSON unmarshal error: %v", err)
	}

	return rel, nil
}

func handleArtist(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		w.WriteHeader(http.StatusMethodNotAllowed)
		ThrowError("400", w, nil)
		return
	}

	if r.URL.Path != "/artist" {
		w.WriteHeader(http.StatusNotFound)
		ThrowError("404", w, nil)
		return
	}

	artistID := r.FormValue("id")
	fmt.Println("Received artist ID:", artistID)
	// Check if artistID is empty
	if artistID == "" {
		http.Error(w, "Artist ID is required", http.StatusBadRequest)
		return
	}

	idNum, err := strconv.Atoi(artistID)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		ThrowError("500", w, nil)
		return
	}

	if idNum < 1 || idNum > len(artists1) {
		http.Error(w, "Invalid artist ID", http.StatusBadRequest)
		return
	}

	fmt.Println("Parsed artist ID:", idNum)
	fmt.Println("Total artists available:", len(artists1))

	rel, err := fetchRelations(idNum)
	if err != nil {
		fmt.Println("error please ", err)
		http.Error(w, "Error fetching relations", http.StatusInternalServerError)
		return
	}

	artist := artists1[idNum-1]
	bigstruct := BigStruct{
		Artist:    artist,
		Relations: rel,
	}
	executeTemp(w, "artist.html", bigstruct)
}

func sub1(x int) int {
	return x - 1
}