package main

import (
	"bytes"
	"encoding/json"
  "encoding/base64"
	"fmt"
	"github.com/arran4/golang-ical"
	"io"
	"net/http"
	"strings"
	"time"
)

const (
	API_URL = "https://api.events.ccc.de/congress/2024"
)

var ROOMS []Room;

type Token struct {
	Token string `json:"token"`
}

type Auth struct {
	Username string `json:"username"`
	Password string `json:"password"`
}

type Event struct {
	ID               string    `json:"id"`
	Kind             string    `json:"kind"`
	Name             string    `json:"name"`
	Slug             string    `json:"slug"`
	URL              string    `json:"url"`
	Track            string    `json:"track"`
	Assembly         string    `json:"assembly"`
	Room             string    `json:"room"`
	Location         string    `json:"location"`
	Language         string    `json:"language"`
	Description      string    `json:"description"`
	ScheduleStart    time.Time `json:"schedule_start"`
	ScheduleDuration string    `json:"schedule_duration"`
	ScheduleEnd      time.Time `json:"schedule_end"`
}

// Link represents the structure of the "links" array in the JSON
type Link struct {
	Type string `json:"type"`
	Name string `json:"name"`
	URI  string `json:"uri"`
	URL  string `json:"url"`
}

// Room represents the structure of the main JSON object
type Room struct {
	ID        string `json:"id"`
	Name      string `json:"name"`
	Slug      string `json:"slug"`
	RoomType  string `json:"room_type"`
	Capacity  int    `json:"capacity"`
	Links     []Link `json:"links"`
	Assembly  string `json:"assembly"`
	PublicURL string `json:"public_url"`
}

func scrape_hub() ([]Event, error) {
	println("scrape hub")
	resp, err := http.Get(fmt.Sprintf("%s/events", API_URL))
	if err != nil {
		fmt.Println("Error making GET request:", err)
		return nil, err
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		fmt.Println("Error reading response body:", err)
		return nil, err
	}

	var events []Event

	if err := json.Unmarshal(body, &events); err != nil {
		fmt.Println("Error unmarshalling JSON:", err)
		return nil, err
	}

	// Use the events slice here
	fmt.Println("Number of events:", len(events))
	return events, nil
}

func get_rooms() ([]Room, error) {
	println("get rooms")
	resp, err := http.Get(fmt.Sprintf("%s/rooms", API_URL))
	if err != nil {
		fmt.Println("Error making GET request:", err)
		return nil, err
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		fmt.Println("Error reading response body:", err)
		return nil, err
	}

	var rooms []Room

	if err := json.Unmarshal(body, &rooms); err != nil {
		fmt.Println("Error unmarshalling JSON:", err)
		return nil, err
	}

	// Use the events slice here
	fmt.Println("Number of rooms:", len(rooms))
	return rooms, nil
}

func get_token(username string, password string) (string, error) {
	println("get token")

	jsonBytes, err := json.Marshal(Auth{Username: username, Password: password})
	if err != nil {
		fmt.Println("Error unmarshalling JSON:", err)
		return "", err
	}

	resp, err := http.Post(
		fmt.Sprintf("%s/auth/get-token", API_URL),
		"application/json",
		bytes.NewBuffer(jsonBytes),
	)
	if err != nil {
		fmt.Println("Error getting Token:", err)
		return "", err
	}
	defer resp.Body.Close()
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		fmt.Println("Error reading response body:", err)
		return "", err
	}
	var token Token
	if err := json.Unmarshal(body, &token); err != nil {
		fmt.Println("Error unmarshalling JSON:", err)
		return "", err
	}
  println(token.Token)
	return token.Token, nil
}

func get_me_events(token string) ([]string, error) {
	println("get personal events")

	req, err := http.NewRequest(
		"GET",
		fmt.Sprintf("%s/me/events", API_URL),
		nil,
	)
	req.Header.Set("Authorization", fmt.Sprintf("Token %s", token))

	resp, err := (&http.Client{}).Do(req)
	if err != nil {
		fmt.Println("Error fetching personal events:", err)
		return nil, err
	}
	defer resp.Body.Close()
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		fmt.Println("Error reading response body:", err)
		return nil, err
	}
  println(string(body))
	var uuids []string
	if err := json.Unmarshal(body, &uuids); err != nil {
		fmt.Println("Error unmarshalling JSON:", err)
		return nil, err
	}
	return uuids, nil
}

func get_schedule(w http.ResponseWriter, r *http.Request) {
	println("/event.ics")
	auth_header := r.Header.Get("Authorization")
  println(auth_header)
	if auth_header == "" {
    http.Error(w, "Unauthorized", http.StatusUnauthorized)
		return
	}
  credentials_encoded := auth_header[len("Basic "):]
  credentials, err := base64.StdEncoding.DecodeString(credentials_encoded)
  if err != nil {
    http.Error(w, "Unauthorized", http.StatusUnauthorized)
    return
  }
  auth := strings.SplitN(string(credentials), ":", 2)
  if len(auth) != 2 {
    http.Error(w, "Unauthorized", http.StatusUnauthorized)
    return
  }
	username := auth[0]
	password := auth[1]

  println(username, password)

	token, err := get_token(username, password)
	if err != nil {
    http.Error(w, "Unauthorized", http.StatusUnauthorized)
		return
	}
	ids, err := get_me_events(token)
	if err != nil {
    http.Error(w, "Unauthorized", http.StatusUnauthorized)
		return
	}
	schedule, err := scrape_hub()
	if err != nil {
    http.Error(w, "Unauthorized", http.StatusUnauthorized)
		return
	}

	var my_events []Event
	for _, event := range schedule {
		for _, id := range ids {
			if event.ID == id {
				my_events = append(my_events, event)
				break
			}
		}
	}

	cal := ics.NewCalendar()
	cal.SetMethod(ics.MethodRequest)
	for _, event := range my_events {
    var location = ""
    for _, room := range ROOMS {
      if event.Room == room.ID {
        location = room.Name
      }
    }

		cal_event := cal.AddEvent(event.ID)
		cal_event.SetStartAt(event.ScheduleStart)
		cal_event.SetEndAt(event.ScheduleEnd)
		cal_event.SetSummary(event.Name)
		cal_event.SetLocation(location)
		cal_event.SetDescription(ics.ToText(strings.ReplaceAll(event.Description, "\r\n", "\n")))
		cal_event.SetURL(event.URL)
		cal_event.SetOrganizer(event.Assembly)
	}

	ics := cal.Serialize()

	w.Header().Set("Content-Type", "text/calendar; charset=utf-8")
	w.Write([]byte(ics))
}

func main() {
	rooms, err := get_rooms()
	if err != nil {
		return
	}
  ROOMS = rooms

	println("Stating Server")
	// Start a web server to serve the iCal file
	http.HandleFunc("/events.ics", get_schedule)
	err = http.ListenAndServe(":8080", nil)
	if err != nil {
		println(err)
	}
}