Implemented a solution for 'undo delete'.

ihatemoney/messages.pot

@@ -204,6 +204,9 @@ msgstr ""
 msgid "The bill has been deleted"
 msgstr ""
 
+msgid "UNDO"
+msgstr ""
+
 msgid "The bill has been modified"
 msgstr ""
 

ihatemoney/templates/list_bills_post_delete.html

@@ -0,0 +1,185 @@
+{% extends "sidebar_table_layout.html" %}
+
+{% block title %} - {{ g.project.name }}{% endblock %}
+{% block js %}
+    {% if add_bill %} $('#new-bill > a').click(); {% endif %}
+
+    // ask for confirmation before removing an user
+    $('.action.delete').each(function(){
+        var link = $(this).find('button');
+        link.click(function(){
+            if ($(this).hasClass("confirm")){
+                return true;
+            }
+            $(this).html("{{_("you sure?")}}");
+            $(this).addClass("confirm");
+            return false;
+        });
+    });
+
+    var highlight_owers = function(){
+        var ower_ids = $(this).attr("owers").split(',');
+        var payer_id = $(this).attr("payer");
+        $.each(ower_ids, function(i, val){
+            $('#bal-member-'+val).addClass("ower_line");
+        });
+        $("#bal-member-"+payer_id).addClass("payer_line");
+    };
+
+    var unhighlight_owers = function(){
+        $('[id^="bal-member-"]').removeClass("ower_line payer_line");
+    };
+
+    $('#bill_table tbody tr').hover(highlight_owers, unhighlight_owers);
+
+{% endblock %}
+
+{% block sidebar %}
+    <div class="sidebar_content">
+        <form id="add-member-form" action="{{ url_for(".add_member") }}" method="post">
+            {{ forms.add_member(member_form) }}
+        </form>
+
+        <div id="table_overflow">
+        <table class="balance table">
+        {% set balance = g.project.balance %}
+        {% for member in g.project.members | sort(attribute='name') if member.activated or balance[member.id]|round(2) != 0 %}
+        <tr id="bal-member-{{ member.id }}" action={% if member.activated %}delete{% else %}reactivate{% endif %}>
+            <td class="balance-name">{{ member.name }}
+                <span class="light{% if not g.project.uses_weights %} extra-info{% endif %}">(x{{ member.weight|minimal_round(1) }})</span>
+            </td>
+            {% if member.activated %}
+            <td>
+                <form class="action delete" action="{{ url_for(".remove_member", member_id=member.id) }}" method="POST">
+                    <button type="submit">{{ _("deactivate") }}</button></form>
+                <form class="action edit" action="{{ url_for(".edit_member", member_id=member.id) }}" method="GET">
+                    <button type="submit">{{ _("edit") }}</button></form>
+            </td>
+            {% else %}
+            <td>
+                <form class="action reactivate" action="{{ url_for(".reactivate", member_id=member.id) }}" method="POST">
+                    <button type="submit">{{ _("reactivate") }}</button></form></td>
+            {% endif %}
+            <td class="balance-value {% if balance[member.id]|round(2) > 0 %}positive{% elif balance[member.id]|round(2) < 0 %}negative{% endif %}">
+                {% if balance[member.id]|round(2) > 0 %}+{% endif %}{{ "%.2f" | format(balance[member.id]) }}
+            </td>
+        </tr>
+        {% endfor %}
+        </table>
+        </div>
+    </div>
+    <div class="identifier">
+        <a class="btn btn-secondary btn-block" href="{{ url_for('.invite') }}">
+            <i class="icon icon-white paper-plane">{{ static_include("images/paper-plane.svg") | safe }}</i>
+            {{ _("Invite people") }}
+        </a>
+    </div>
+{% endblock %}
+
+{% block content %}
+    <span id="undo" class="float-left">
+        <a href="{{ url_for('.undo_delete_bill') }}" method="get" class="btn btn-primary float-left">
+            {{ _("Undo delete") }}
+        </a>
+    </span>
+    <span id="new-bill" class="float-right"  {% if not g.project.members %} data-toggle="tooltip" title="{{_('You should start by adding participants')}}" {% endif %}>
+        <a href="{{ url_for('.add_bill') }}" class="btn btn-primary float-right {% if not g.project.members %} disabled {% endif %}" data-toggle="modal" data-keyboard="false" data-target="#bill-form">
+            <i class="icon icon-white plus">{{ static_include("images/plus.svg") | safe }}</i>
+            {{ _("Add a new bill") }}
+        </a>
+    </span>
+    <div id="bill-form" class="modal fade show" role="dialog">
+        <div class="modal-dialog" role="document">
+            <div class="modal-content">
+                <div class="modal-header">
+                    <h3 class="modal-title">{{ _('Add a bill') }}</h3>
+                    <a href="#" class="close" data-dismiss="modal">&times;</a>
+                </div>
+                <form action="{{ url_for(".add_bill") }}" method="post" class="modal-body container">
+                {{ forms.add_bill(bill_form, title=False) }}
+                </form>
+            </div>
+        </div>
+    </div>
+
+{% if bills.pages > 1 %}
+    <span id="previous-page" class="float-left">
+      <a class="btn btn-outline-secondary float-left {% if bills.page == 1 %}disabled{% endif %}" href="{{ url_for('main.list_bills', page=bills.prev_num) }}">&laquo; {{ _("Newer bills") }}</a>
+    </span>
+
+    <span id="next-page" class="float-left">
+      <a class="btn btn-outline-secondary float-left {% if bills.page == bills.pages %}disabled{% endif %}" href="{{ url_for('main.list_bills', page=bills.next_num) }}">{{ _("Older bills") }} &raquo;</a>
+    </span>
+{% endif %}
+
+    {% if bills.total > 0 %}
+        <div class="clearfix"></div>
+
+        <table id="bill_table" class="col table table-striped table-hover table-responsive-sm">
+            <thead><tr><th>{{ _("When?") }}</th><th>{{ _("Who paid?") }}</<th><th>{{ _("For what?") }}</th><th>{{ _("For whom?") }}</th><th>{{ _("How much?") }}</th><th>{{ _("Actions") }}</th></tr></thead>
+        <tbody>
+        {% for bill in bills.items %}
+        <tr owers="{{bill.owers|join(',','id')}}" payer="{{bill.payer.id}}">
+                <td>
+                    <span data-toggle="tooltip" data-placement="top"
+                        title="{{ _('Added on %(date)s', date=bill.creation_date if bill.creation_date else bill.date) }}">
+                        {{ bill.date }}
+                    </span>
+                </td>
+                <td>{{ bill.payer }}</td>
+                <td>{{ bill.what }}</td>
+                <td>{% if bill.owers|length == g.project.members|length -%}
+                {{ _("Everyone") }}
+                {%- elif bill.owers|length > g.project.members|length / 2 + 1 -%}
+                {{ _("Everyone but %(excluded)s", excluded=g.project.members|reject('in', bill.owers)|join(', ', 'name')) }}
+                {%- else -%}
+                {{ bill.owers|join(', ', 'name') }}
+                {%- endif %}</td>
+                <td>{{ "%0.2f"|format(bill.amount) }} ({{ "%0.2f"|format(bill.pay_each()) }} {{ _("each") }})</td>
+                <td class="bill-actions">
+                    <a class="edit" href="{{ url_for(".edit_bill", bill_id=bill.id) }}" title="{{ _("edit") }}">{{ _('edit') }}</a>
+                    <a class="delete" href="{{ url_for(".delete_bill", bill_id=bill.id) }}" title="{{ _("delete") }}">{{ _('delete') }}</a>
+                    {% if bill.external_link %}
+                    <a class="see" href="{{ bill.external_link }}" ref="noopener" target="_blank" title="{{ _("see") }}">{{ _('see') }} </a>
+                    {% endif %}
+                </td>
+        </tr>
+        {% endfor %}
+        </tbody>
+        </table>
+
+{% if bills.pages > 1 %}
+<ul class="pagination">
+  <li class="page-item {% if bills.page == 1 %}disabled{% endif %}"><a class="page-link" href="{{ url_for('main.list_bills', page=bills.prev_num) }}">&laquo; Newer bills</a></li>
+  {%- for page in bills.iter_pages() %}
+  {% if page %}
+  <li class="page-item {% if page == bills.page %}active{% endif %}"><a class="page-link" href="{{ url_for('main.list_bills', page=page) }}">{{ page }}</a></li>
+  {% else %}
+  <li class="page-item disabled"><span class="ellipsis page-link">…</span></li>
+  {% endif %}
+  {%- endfor %}
+  <li class="page-item {% if bills.page == bills.pages %}disabled{% endif %}"><a class="page-link" href="{{ url_for('main.list_bills', page=bills.next_num) }}">Older bills &raquo;</a></li>
+</ul>
+{% endif %}
+
+    {% else %}
+        <div class="py-3 d-flex justify-content-center empty-bill">
+        <div class="card d-inline-flex p-2">
+            <div class="card-body text-center text-muted">
+                <i class="icon icon-white hand-holding-heart">{{ static_include("images/hand-holding-heart.svg") | safe }}</i>
+                <h3>{{ _('No bills')}}</h3>
+                <p>
+                    {{ _("Nothing to list yet.")}}<br />
+                    {{ _("You probably want to") }}
+                    {%- if g.project.members %} <a href="{{ url_for('.add_bill') }}" data-toggle="modal" data-target="#bill-form">
+                            {{- _("add a bill") -}}
+                        </a> ?
+                    {% else %} <a href="{{ url_for('.add_member') }}">
+                            {{- _('add participants') -}}
+                        </a> ?
+                    {%- endif -%}
+                </p>
+            </div>
+        </div></div>
+    {% endif %}
+{% endblock %}

ihatemoney/tests/tests.py

@@ -673,6 +673,7 @@ class BudgetTestCase(IhatemoneyTestCase):
         balance = models.Project.query.get("raclette").balance
         self.assertEqual(set(balance.values()), set([19.0, -19.0]))
 
+
         # Bill with negative amount
         self.client.post(
             "/raclette/add",
@@ -787,6 +788,61 @@ class BudgetTestCase(IhatemoneyTestCase):
         self.client.post("/raclette/members/add", data={"name": "fred"})
         self.client.post("/raclette/members/add", data={"name": "tata"})
 
+        # create bills, then delete and undo
+        self.client.post(
+            "/raclette/add",
+            data={
+                "date": "2020-04-22",
+                "what": "Glover Apts. Rent April",
+                "payer": 1,
+                "payed_for": [1, 2, 3],
+                "amount": "852.00",
+            },
+        )
+
+        balance = models.Project.query.get("raclette").balance
+        self.assertEqual(set(balance.values()), set([568.00, -284.00, -284.00]))
+
+        self.client.post(
+            "/raclette/add",
+            data={
+                "data": "2020-05-22",
+                "what": "Glover Apts. Rent May",
+                "payer": 2,
+                "payed_for": [1, 2, 3],
+                "amount": "852.00",
+            },
+        )
+
+        balance = models.Project.query.get("raclette").balance
+        self.assertEqual(set(balance.values()), set([284.00, 284.00, -568.00]))
+
+        bill = models.Bill.query.one()
+        self.assertEqual(bill.amount, 852.00)
+
+        # delete the first bill
+        self.client.get("/raclette/delete/%s" % bill.id)
+        self.assertEqual(1, len(models.Bill.query.all()), "bill deletion")
+
+        # check balance
+        balance = models.Project.query.get("raclette").balance
+        self.assertEqual(set(balance.values()), set([-284.00, 568.00, -284.00]))
+
+        # undo delete
+        self.client.get("/raclette/undo")
+
+        # recheck balance
+        balance = models.Project.query.get("raclette").balance
+        self.assertEqual(set(balance.values()), set([284.00, 284.00, -568.00]))
+
+        # delete both bills
+        bill = models.Bill.query.one()
+        self.client.get("/raclette/delete/%s" % bill.id)
+        bill = models.Bill.query.one()
+        self.client.get("/raclette/delete/%s" % bill.id)
+        balance = models.Project.query.get("raclette").balance
+        self.assertEqual(set(balance.values()), set([0, 0, 0]))
+
         # create bills
         self.client.post(
             "/raclette/add",

ihatemoney/web.py

@@ -12,6 +12,7 @@ from datetime import datetime
 from functools import wraps
 import json
 import os
+import copy
 from smtplib import SMTPRecipientsRefused
 
 from dateutil.parser import parse
@@ -64,6 +65,8 @@ main = Blueprint("main", __name__)
 
 login_throttler = LoginThrottler(max_attempts=3, delay=1)
 
+ghost_billform = None
+
 
 def requires_admin(bypass=None):
     """Require admin permissions for @requires_admin decorated endpoints.
@@ -213,8 +216,8 @@ def authenticate(project_id=None):
 
     project = Project.query.get(project_id)
     if not project:
-        # If the user try to connect to an unexisting project, we will
+        # If the user tries to connect to an unexisting project, we will
-        # propose him a link to the creation form.
+        # provide them with a link to the creation form.
         return render_template(
             "authenticate.html", form=form, create_project=project_id
         )
@@ -620,7 +623,7 @@ def add_member():
         if form.validate():
             member = form.save(g.project, Person())
             db.session.commit()
-            flash(_("%(member)s had been added", member=member.name))
+            flash(_("%(member)s has been added", member=member.name))
             return redirect(url_for(".list_bills"))
 
     return render_template("add_member.html", form=form)
@@ -699,17 +702,62 @@ def add_bill():
     return render_template("add_bill.html", form=form)
 
 
-@main.route("/<project_id>/delete/<int:bill_id>")
+@main.route("/<project_id>/delete/<int:bill_id>", methods=["GET", "POST"])
 def delete_bill(bill_id):
+    global ghost_billform
+    ghost_billform = get_billform_for(g.project)
     # fixme: everyone is able to delete a bill
     bill = Bill.query.get(g.project, bill_id)
     if not bill:
         return redirect(url_for(".list_bills"))
 
+    # save the deleted bill, so that it can be restored if the
+    # user chooses to undo this action
+    ghost_billform.fill(bill)
+
     db.session.delete(bill)
     db.session.commit()
     flash(_("The bill has been deleted"))
 
+    return redirect(url_for(".post_delete"))
+
+
+@main.route("/<project_id>/post_delete", methods=["GET", "POST"])
+def post_delete():
+    # this functions identically to list_bills, however
+    # the undo action button is added
+    bill_form = get_billform_for(g.project)
+    # set the last selected payer as default choice if exists
+    if "last_selected_payer" in session:
+        bill_form.payer.data = session["last_selected_payer"]
+    # Preload the "owers" relationship for all bills
+    bills = (
+        g.project.get_bills()
+        .options(orm.subqueryload(Bill.owers))
+        .paginate(per_page=100, error_out=True)
+    )
+
+    return render_template(
+        "list_bills_post_delete.html",
+        bills=bills,
+        member_form=MemberForm(g.project),
+        bill_form=bill_form,
+        add_bill=request.values.get("add_bill", False),
+        current_view="list_bills_post_delete",
+    )
+
+
+@main.route("/<project_id>/undo", methods=["GET", "POST"])
+def undo_delete_bill():
+    global ghost_billform
+    args = {}
+
+    bill = Bill()
+    db.session.add(ghost_billform.save(bill, g.project))
+    db.session.commit()
+
+    flash(_("Restored bill"))
+
     return redirect(url_for(".list_bills"))