package main

import (
	"database/sql"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"time"

	_ "github.com/lib/pq"
)

//Go Best practices: https://github.com/golovers/effective-go
type Item struct {
	Id                int32       `json:"id"`
	Name              int32       `json:"name"`
	ValueCents        int32       `json:"valueCents"`
	PurchaseCostCents int32       `json:"purchasedCostCents"`
	Aquired           time.Time   `json:"aquired"`
	Description       string      `json:"description"`
	Notes             string      `json:"notes"`
	SoldForCents      int32       `json:"soldForCents"`
	SoldTo            string      `json:"soldTo"`
	Category          Category    `json:"category"`
	Subcategory       Subcategory `json:"subcategory"`
}

type Category struct {
	Id   int32  `json:"id"`
	Name string `json:"name"`
}

type Subcategory struct {
	Id         int32  `json:"id"`
	Name       string `json:"name"`
	CategoryId int32  `json:"categoryId"`
}

func main() {
	http.HandleFunc("/categories", categories)
	err := http.ListenAndServe(":8080", nil)

	if err != nil {
		panic(err)
	}

}

func categories(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case "GET":
		getCategories(w, r)
	case "POST":
		insertCategory(w, r)
	default:
		w.WriteHeader(http.StatusMethodNotAllowed)
		w.Write([]byte("Method not allowed"))
	}
}

func getCategories(w http.ResponseWriter, r *http.Request) {
	//Note: The postgres driver seems to get confused when no password is supplied, so omit it in the connection sting.
	//https://rajyavardhan.medium.com/when-you-get-relation-does-not-exist-in-postgres-7ffb0c3c674b
	psqlInfo := fmt.Sprintf("host=%s port=%d user=%s dbname=%s sslmode=disable", "localhost", 5432, "postgres", "inv")
	db, err := sql.Open("postgres", psqlInfo)

	if err != nil {
		panic(err)
	}

	defer db.Close()

	rows, err := db.Query("SELECT * FROM category;")

	if err != nil {
		panic(err)
	}

	defer rows.Close()

	var categories []Category

	for rows.Next() {
		var category Category

		if err = rows.Scan(&category.Id, &category.Name); err != nil {
			println(err.Error())
		}

		categories = append(categories, category)
	}

	jsonBytes, err := json.Marshal(categories)

	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte("Failed to get a list of categories."))
		return
	}

	w.WriteHeader(http.StatusOK)
	w.Write(jsonBytes)
}

func insertCategory(w http.ResponseWriter, r *http.Request) {
	bodyBytes, err := ioutil.ReadAll(r.Body)

	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte("Failed to parse request body"))
		return
	}

	var category Category

	err = json.Unmarshal(bodyBytes, &category)

	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte("Failed to unmarshal JSON"))
		return
	}

	psqlInfo := fmt.Sprintf("host=%s port=%d user=%s dbname=%s sslmode=disable", "localhost", 5432, "postgres", "inv")
	db, err := sql.Open("postgres", psqlInfo)

	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte("Failed to connect to the DB"))
		return
	}

	id := 0

	err = db.QueryRow("INSERT INTO category (category_name) VALUES ($1) RETURNING category_id", category.Name).Scan(&id)

	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte(err.Error()))
		return
	}

	w.WriteHeader(http.StatusOK)
	w.Write([]byte(fmt.Sprint("New Record: ", id)))
}