From c00b690bd6f600554a1404e692bd9e4373325d27 Mon Sep 17 00:00:00 2001
From: Leonardo Bishop <me@leonardobishop.com>
Date: Fri, 17 Jan 2025 13:21:24 +0000
Subject: Initial commit

---
 pkg/user/service.go | 121 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)
 create mode 100644 pkg/user/service.go

(limited to 'pkg/user/service.go')

diff --git a/pkg/user/service.go b/pkg/user/service.go
new file mode 100644
index 0000000..7784811
--- /dev/null
+++ b/pkg/user/service.go
@@ -0,0 +1,121 @@
+package user
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/LMBishop/confplanner/pkg/database/sqlc"
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgconn"
+	"github.com/jackc/pgx/v5/pgxpool"
+	"golang.org/x/crypto/bcrypt"
+)
+
+type Service interface {
+	CreateUser(username string, password string) (*sqlc.User, error)
+	GetUserByName(username string) (*sqlc.User, error)
+	GetUserByID(id int32) (*sqlc.User, error)
+	Authenticate(username string, password string) (*sqlc.User, error)
+}
+
+var (
+	ErrUserExists                = errors.New("user already exists")
+	ErrUserNotFound              = errors.New("user not found")
+	ErrNotAcceptingRegistrations = errors.New("not currently accepting registrations")
+)
+
+type service struct {
+	pool                   *pgxpool.Pool
+	acceptingRegistrations bool
+}
+
+func NewService(pool *pgxpool.Pool, acceptingRegistrations bool) Service {
+	return &service{
+		pool:                   pool,
+		acceptingRegistrations: acceptingRegistrations,
+	}
+}
+
+func (s *service) CreateUser(username string, password string) (*sqlc.User, error) {
+	if !s.acceptingRegistrations {
+		return nil, ErrNotAcceptingRegistrations
+	}
+
+	queries := sqlc.New(s.pool)
+
+	var passwordBytes = []byte(password)
+
+	hash, err := bcrypt.GenerateFromPassword(passwordBytes, bcrypt.DefaultCost)
+	if err != nil {
+		return nil, fmt.Errorf("could not hash password: %w", err)
+	}
+
+	user, err := queries.CreateUser(context.Background(), sqlc.CreateUserParams{
+		Username: strings.ToLower(username),
+		Password: string(hash),
+	})
+	if err != nil {
+		var pgErr *pgconn.PgError
+		if errors.As(err, &pgErr) && pgErr.Code == "23505" {
+			return nil, ErrUserExists
+		}
+		return nil, fmt.Errorf("could not create user: %w", err)
+	}
+
+	return &user, nil
+}
+
+func (s *service) GetUserByName(username string) (*sqlc.User, error) {
+	queries := sqlc.New(s.pool)
+
+	user, err := queries.GetUserByName(context.Background(), username)
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return nil, ErrUserNotFound
+		}
+		return nil, fmt.Errorf("could not fetch user: %w", err)
+	}
+
+	return &user, nil
+}
+
+func (s *service) GetUserByID(id int32) (*sqlc.User, error) {
+	queries := sqlc.New(s.pool)
+
+	user, err := queries.GetUserByID(context.Background(), id)
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return nil, ErrUserNotFound
+		}
+		return nil, fmt.Errorf("could not fetch user: %w", err)
+	}
+
+	return &user, nil
+}
+
+func (s *service) Authenticate(username string, password string) (*sqlc.User, error) {
+	random, err := bcrypt.GenerateFromPassword([]byte("00000000"), bcrypt.DefaultCost)
+	if err != nil {
+		return nil, err
+	}
+
+	user, err := s.GetUserByName(username)
+	if err != nil {
+		if errors.Is(err, ErrUserNotFound) {
+			bcrypt.CompareHashAndPassword(random, []byte(password))
+			return nil, nil
+		}
+		return nil, err
+	}
+
+	if err = bcrypt.CompareHashAndPassword([]byte(user.Password), []byte(password)); err != nil {
+		if errors.Is(err, bcrypt.ErrMismatchedHashAndPassword) {
+			return nil, nil
+		}
+		return nil, err
+	}
+
+	return user, nil
+}
-- 
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