Improve log in, add product adding

style.css

@@ -63,3 +63,12 @@ main {
 .cart__price {
     width: 65px;
 }
+
+.login__reason {
+    padding: 8px 8px;
+    margin: 16px 0;
+    border-radius: 2px;
+    border: 1px solid #bee5eb;
+    background: #d1ecf1;
+    color: #0c5460;
+}

views/login.pl

@@ -1,6 +1,16 @@
 :- http_handler(root(login), login_view(Method), [method(Method), methods([get, post])]).
+:- http_handler(root(logout), logout_view, []).
 :- http_handler(root('style.css'), http_reply_file('style.css', []), []).
 
+
+login_reason -->
+    {
+        http_session_data(reason(Reason)),
+        http_session_retract(reason(_))
+    }, !,
+    html(div(class=login__reason, Reason)).
+login_reason --> [].
+
 login_view(get, _Request) :-
     reply_html_page(
         [
@@ -13,6 +23,7 @@ login_view(get, _Request) :-
         ],
         [
             h1('Login'),
+            \login_reason,
             form([method=post], [
                 div([
                     label(for=username, 'Username'),
@@ -20,7 +31,9 @@ login_view(get, _Request) :-
                         type=text,
                         placeholder='Username',
                         name=username,
-                        id=username
+                        id=username,
+                        autofocus,
+                        required
                     ])
                 ]),
 
@@ -30,7 +43,8 @@ login_view(get, _Request) :-
                         type=password,
                         placeholder='Username',
                         name=password,
-                        id=password
+                        id=password,
+                        required
                     ])
                 ]),
 
@@ -46,19 +60,40 @@ login_view(get, _Request) :-
 
 login_view(post, Request) :-
     http_read_data(Request, [username=Username, password=Password], []),
-    handle_login(Username, Password, Reply),
-    reply_prolog(Reply).
+    handle_login(Username, Password, Request).
+
+
+create_user(Username, _) :-
+    user(Username, _), !,
+    format("User already exists.~n"),
+    false.
+
+create_user(Username, Password) :-
+    crypto_password_hash(Password, Hash),
+    assert_user(Username, Hash).
 
 
 % Handles logging in, returning the correct Json in Reply.
-handle_login(Username, Password, Reply) :-
+handle_login(Username, Password, Request) :-
     user(Username, Hash),
     crypto_password_hash(Password, Hash), !,
-    assert_session(Username, Token),
-    Reply = true.
+    http_session_assert(user(Username)),
+    (http_session_retract(from(From)); From = .),
+    http_redirect(see_other, root(From), Request).
 
-handle_login(Username, _, Reply) :-
+handle_login(Username, _, Request) :-
     user(Username, _), !,
-    Reply = incorrect_password.
+    http_session_assert(reason('Invalid password.')),
+    http_redirect(see_other, root(login), Request).
 
-handle_login(_, _, incorrect_user).
+handle_login(_, _, Request) :-
+    http_session_assert(reason('Unknown username.')),
+    http_redirect(see_other, root(login), Request).
+
+
+logout_view(Request) :-
+    http_session_retract(user(_)),
+    http_redirect(see_other, root(.), Request).
+
+logout_view(Request) :-
+    http_redirect(see_other, root(.), Request).

views/products.pl

@@ -1,10 +1,44 @@
-:- http_handler(root(.), products_view, []).
+:- http_handler(root(.), products_view(Method), [method(Method), methods([get, post])]).
 :- http_handler(root('style.css'), http_reply_file('style.css', []), []).
 
 price_str(Price, PriceStr) :-
     Euro is Price / 100,
     format(atom(PriceStr), '€ ~2f', Euro).
 
+products_add -->
+    {http_session_data(user(_))}, !,  % Check if we're logged in
+    html(
+        div([
+            h2('Add product'),
+            form([method=post], [
+                div([
+                    label(for=name, 'Name'),
+                    input([
+                        type=text,
+                        placeholder='Name',
+                        name=name,
+                        id=name,
+                        required
+                    ])
+                ]),
+
+                div([
+                    label(for=price, 'Price'),
+                    input([
+                        type=text,
+                        placeholder='Price',
+                        name=price,
+                        id=price,
+                        required
+                    ])
+                ]),
+
+                div(input(type=submit))
+            ])
+        ])
+    ).
+products_add --> [].  % If not, do not show
+
 products_list([]) --> [].
 products_list([product(Name, Price)|Products]) -->
     {price_str(Price, PriceStr)},
@@ -34,7 +68,16 @@ cart([Name|Items]) -->
     ]),
     cart(Items).
 
-products_view(_Request) :-
+account -->
+    {http_session_data(user(Username))}, !,
+    html([
+        div(['Hello ', Username, '!']),
+        a(href('/logout'), 'Log out')
+    ]).
+account -->
+    html(a(href('/login'), 'Log in')).
+
+products_view(get, _Request) :-
     http_session_id(SessionId),
     (bagof(product(X, Y), product(X, Y), Products); Products = []),
     (bagof(Name, cart_entry(SessionId, Name), CartEntries); CartEntries = []),
@@ -52,6 +95,23 @@ products_view(_Request) :-
             main([
                 div(class(products), \products_list(Products)),
                 div(class(cart), \cart(CartEntries))
-            ])
+            ]),
+            \products_add,
+            h2('Account'),
+            \account
         ]
     ).
+
+products_view(post, Request) :-
+    % Check if we're logged in
+    \+ http_session_data(user(_)), !,
+    http_session_assert(reason('You need to be logged in to do this.')),
+    http_redirect(see_other, root(login), Request).
+
+products_view(post, Request) :-
+    http_read_data(Request, [name=Name, price=Price], []),
+    atom_number(Price, PriceNumber),
+    Cents is round(PriceNumber * 100),
+    retractall_product(Name, _),
+    assert_product(Name, Cents),
+    http_redirect(see_other, root(.), Request).