package main

import (
	"encoding/json"
	"fmt"
	"log"
	"math/rand"
	"net/http"
	"strconv"
	"github.com/gorilla/mux"
)

// Book Struct ( Class-like i guess ?) - Looks like ES6 classes or JAVA
type Book struct {
	ID     string  `json:id`
	ISBN   string  `json:isbn`
	Title  string  `json:title`
	Author *Author `json:author`
}

// Author Struct, sub-struct to book
type Author struct {
	Firstname string `json:firstname`
	Lastname  string `json:lastname`
}

// Init books var as a slice (variable array)
var books []Book

// Get all books
func getBooks(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(books)
}

// Get a single book by id
func getBook(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	params := mux.Vars(r) // Get params

	// Find correct book with id r
	for _, item := range books {

		fmt.Println(item.ID, params["id"])
		fmt.Printf("%+v\n", books)
		if item.ID == params["id"] {
			json.NewEncoder(w).Encode(item)
			return
		}
	}

	json.NewEncoder(w).Encode(&Book{})
}

// Create a new book
func createBook(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	fmt.Println(r.Body)
	var book Book
	_ = json.NewDecoder(r.Body).Decode(&book)
	book.ID = strconv.Itoa(rand.Intn(10000000)) // Mock ID - shitty duplicates
	books = append(books, book)
	json.NewEncoder(w).Encode(book)

}

// Updates an existing book
func updateBook(w http.ResponseWriter, r *http.Request) {

}

// Deletes a book by id
func deleteBook(w http.ResponseWriter, r *http.Request) {

}

func main() {

	// Initialize router
	r := mux.NewRouter()

	// Mock Data - @todo - implement DB
	books = append(books, Book{"1", "AS-465234", "The First Title", &Author{"Simon", "Borgmästars"}})
	books = append(books, Book{"2", "KL-34545", "The Second Title", &Author{"Simon2", "Borgmästars2"}})
	books = append(books, Book{"3", "OP-64545", "The Third Title", &Author{"Simon3", "Borgmästars3"}})
	books = append(books, Book{"4", "UI-90875", "The Fourth Title", &Author{"Simon4", "Borgmästars4"}})

	// Route Handlers
	r.HandleFunc("/api/books", getBooks).Methods("GET")
	r.HandleFunc("/api/books/{id}", getBook).Methods("GET")
	r.HandleFunc("/api/books", createBook).Methods("POST")
	r.HandleFunc("/api/books", updateBook).Methods("PUT")
	r.HandleFunc("/api/books/{id}", deleteBook).Methods("DELETE")

	// Running the server
	fmt.Println("Starting up the server...")
	log.Fatal(http.ListenAndServe(":3000", r))

}