mini-ticket-system/webserver/handlers.go

// TODO: READ AND UNDERSTAND

package main

import (
	"context"
	"encoding/json"
	"net/http"
	"strconv"

	"github.com/go-chi/chi/v5"
)

/*

// GET /quotes
func getQuotes(w http.ResponseWriter, r *http.Request) {
	rows, err := db.Query(context.Background(), "SELECT * FROM hlaskovnik;")
	if err != nil {
		http.Error(w, err.Error(), 500)
		return
	}
	defer rows.Close()

	var quotes []Quote

	for rows.Next() {
		var q Quote
		rows.Scan(&q.Id, &q.Author, &q.Body)
		quotes = append(quotes, q)
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(quotes)
}

// POST /quotes
func createQuote(w http.ResponseWriter, r *http.Request) {
	var q Quote

	err := json.NewDecoder(r.Body).Decode(&q)
	if err != nil {
		http.Error(w, "Invalid JSON", 400)
		return
	}

	err = db.QueryRow(
		context.Background(),
		"INSERT INTO hlaskovnik(author, body) VALUES($1, $2) RETURNING id;",
		q.Author, q.Body,
	).Scan(&q.Id)

	if err != nil {
		http.Error(w, err.Error(), 500)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(q)
}

// PUT /quotes/{id}
func updateQuote(w http.ResponseWriter, r *http.Request) {
	// get ID from URL
	idParam := chi.URLParam(r, "id")
	id, err := strconv.Atoi(idParam)
	if err != nil {
		http.Error(w, "Invalid ID", http.StatusBadRequest)
		return
	}

	// parse request body
	var q Quote
	err = json.NewDecoder(r.Body).Decode(&q)
	if err != nil {
		http.Error(w, "Invalid JSON", http.StatusBadRequest)
		return
	}

	// update DB
	commandTag, err := db.Exec(
		context.Background(),
		`UPDATE hlaskovnik
		 SET author=$1, body=$2
		 WHERE id=$3`,
		q.Author, q.Body, id,
	)
	if err != nil {
		http.Error(w, err.Error(), 500)
		return
	}

	// check if row exists
	if commandTag.RowsAffected() == 0 {
		http.Error(w, "Quote not found", http.StatusNotFound)
		return
	}

	// return updated object
	q.Id = id

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(q)
}

// DELETE /quotes{id}
func deleteQuote(w http.ResponseWriter, r *http.Request) {
	// get id from URL
	idParam := chi.URLParam(r, "id")

	// convert string → int
	id, err := strconv.Atoi(idParam)
	if err != nil {
		http.Error(w, "Invalid ID", http.StatusBadRequest)
		return
	}

	// execute delete
	commandTag, err := db.Exec(
		context.Background(),
		"DELETE FROM hlaskovnik WHERE id=$1",
		id,
	)
	if err != nil {
		http.Error(w, err.Error(), 500)
		return
	}

	// check if anything was deleted
	if commandTag.RowsAffected() == 0 {
		http.Error(w, "Quote not found", http.StatusNotFound)
		return
	}

	// success response
	w.WriteHeader(http.StatusNoContent) // 204
}

*/

// GET /tickets
func getTickets(w http.ResponseWriter, r *http.Request) {
	rows, err := db.Query(context.Background(), "SELECT id, title, description, status, created_at, updated_at FROM tickets ORDER BY id;")
	if err != nil {
		http.Error(w, err.Error(), 500)
		return
	}
	defer rows.Close()

	var tickets []Ticket

	for rows.Next() {
		var t Ticket
		rows.Scan(&t.Id, &t.Title, &t.Description, &t.Status, &t.CreatedAt, &t.UpdatedAt)
		tickets = append(tickets, t)
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(tickets)
}

// POST /tickets
func createTicket(w http.ResponseWriter, r *http.Request) {
	var t Ticket

	err := json.NewDecoder(r.Body).Decode(&t)
	if err != nil {
		http.Error(w, "Invalid JSON", 400)
		return
	}

	err = db.QueryRow(
		context.Background(),
		"INSERT INTO tickets(title, description) VALUES($1, $2) RETURNING id, status, created_at, updated_at;",
		t.Title, t.Description,
	).Scan(&t.Id, &t.Status, &t.CreatedAt, &t.UpdatedAt)

	if err != nil {
		http.Error(w, err.Error(), 500)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(t)
}

// PATCH /tickets/{id}
func updateTicket(w http.ResponseWriter, r *http.Request) {
	// get ID from URL
	idParam := chi.URLParam(r, "id")
	id, err := strconv.Atoi(idParam)
	if err != nil {
		http.Error(w, "Invalid ID", http.StatusBadRequest)
		return
	}

	// parse request body
	var status Status
	err = json.NewDecoder(r.Body).Decode(&status)
	if err != nil {
		http.Error(w, "Invalid JSON", http.StatusBadRequest)
		return
	}

	// update DB
	commandTag, err := db.Exec(
		context.Background(),
		`UPDATE tickets
		 SET status=$1
		 WHERE id=$2`,
		status.Status, id,
	)
	if err != nil {
		http.Error(w, err.Error(), 500)
		return
	}

	// check if row exists
	if commandTag.RowsAffected() == 0 {
		http.Error(w, "Ticket not found", http.StatusNotFound)
		return
	}

	// fetch the updated row to return it
	var t Ticket
	err = db.QueryRow(
		context.Background(),
		`SELECT id, title, description, status, created_at, updated_at
		 FROM tickets
		 WHERE id=$1`,
		id,
	).Scan(&t.Id, &t.Title, &t.Description, &t.Status, &t.CreatedAt, &t.UpdatedAt)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// return updated object
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(t)
}