From 5cdf1c41e0ab382d6f0eb442bc32d8fdf7cc626c Mon Sep 17 00:00:00 2001
From: Pedro Rivotti <44579232+pedrorivotti@users.noreply.github.com>
Date: Fri, 4 Jan 2019 17:05:35 +0000
Subject: [PATCH] Add option to specify start of the week (#240)

* Add function that offsets week start

* Apply offset when week option is used

* Add tests

* Update configuration docs

* Add default fallback value
---
 docs/user-guide/configuration.md |  8 ++++++++
 tests/test_utils.py              | 22 ++++++++++++++++++++--
 watson/cli.py                    | 14 +++++++++++---
 watson/utils.py                  | 17 +++++++++++++++++
 4 files changed, 56 insertions(+), 5 deletions(-)

diff --git a/docs/user-guide/configuration.md b/docs/user-guide/configuration.md
index 9b5a7656..a3f5c987 100644
--- a/docs/user-guide/configuration.md
+++ b/docs/user-guide/configuration.md
@@ -149,6 +149,13 @@ Globally configure how `dates` should be formatted. All [python's `strftime` dir
 
 Globally configure how `time` should be formatted. All [python's `strftime` directives](http://strftime.org) are supported.
 
+#### `options.week_start`
+
+Globally configure which day corresponds to the start of a week. Allowable
+values are `monday` (default), `tuesday`, `wednesday`, `thursday`, `friday`,
+ `saturday`, and `sunday`.
+
+
 ### Default tags
 
 Tags can be automatically added for selected projects. This is convenient when
@@ -211,6 +218,7 @@ stop_on_start = true
 stop_on_restart = false
 date_format = %Y.%m.%d
 time_format = %H:%M:%S%z
+week_start = monday
 log_current = false
 pager = true
 report_current = false
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 1d77cea6..021e82f0 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 """Unit tests for the 'utils' module."""
 
+import arrow
 import functools
 import os
 import datetime
@@ -13,8 +14,8 @@
 import pytest
 from dateutil.tz import tzutc
 
-from watson.utils import (get_start_time_for_period, make_json_writer,
-                          safe_save, parse_tags, PY2)
+from watson.utils import (apply_weekday_offset, get_start_time_for_period,
+                          make_json_writer, safe_save, parse_tags, PY2)
 from . import mock_datetime
 
 
@@ -41,6 +42,23 @@ def test_get_start_time_for_period(now, mode, start_time):
         assert get_start_time_for_period(mode).datetime == start_time
 
 
+@pytest.mark.parametrize("monday_start, week_start, new_start", [
+    ("2018 12 3", "monday", "2018 12 3"),
+    ("2018 12 3", "tuesday", "2018 12 4"),
+    ("2018 12 3", "wednesday", "2018 12 5"),
+    ("2018 12 3", "thursday", "2018 12 6"),
+    ("2018 12 3", "friday", "2018 11 30"),
+    ("2018 12 3", "saturday", "2018 12 1"),
+    ("2018 12 3", "sunday", "2018 12 2"),
+    ("2018 12 3", "typo", "2018 12 3"),
+])
+def test_apply_weekday_offset(monday_start, week_start, new_start):
+    with mock_datetime(_dt(2018, 12, 6), datetime):
+        original_start = arrow.get(monday_start, "YYYY MM D")
+        result = arrow.get(new_start, "YYYY MM D")
+        assert apply_weekday_offset(original_start, week_start) == result
+
+
 def test_make_json_writer():
     fp = StringIO()
     writer = make_json_writer(lambda: {'foo': 42})
diff --git a/watson/cli.py b/watson/cli.py
index 17bb05fc..7b0b1bd4 100644
--- a/watson/cli.py
+++ b/watson/cli.py
@@ -14,9 +14,9 @@
 
 from . import watson as _watson
 from .frames import Frame
-from .utils import (format_timedelta, get_frame_from_argument,
-                    get_start_time_for_period, options, safe_save,
-                    sorted_groupby, style, parse_tags)
+from .utils import (apply_weekday_offset, format_timedelta,
+                    get_frame_from_argument, get_start_time_for_period,
+                    options, safe_save, sorted_groupby, style, parse_tags)
 
 
 class MutuallyExclusiveOption(click.Option):
@@ -57,6 +57,14 @@ def convert(self, value, param, ctx):
             # expected by the user, so that midnight is midnight in the local
             # timezone, not in UTC. Cf issue #16.
             date.tzinfo = tz.tzlocal()
+
+            # Add an offset to match the week beginning specified in the
+            # configuration
+            if param.name == "week":
+                week_start = ctx.obj.config.get(
+                    "options", "week_start", "monday")
+                date = apply_weekday_offset(
+                    start_time=date, week_start=week_start)
             return date
 
 
diff --git a/watson/utils.py b/watson/utils.py
index 16250420..3b46b6a9 100644
--- a/watson/utils.py
+++ b/watson/utils.py
@@ -161,6 +161,23 @@ def get_start_time_for_period(period):
     return start_time
 
 
+def apply_weekday_offset(start_time, week_start):
+    """
+    Apply the offset required to move the start date `start_time` of a week
+    starting on Monday to that of a week starting on `week_start`.
+    """
+    weekdays = dict(zip(
+        ["monday", "tuesday", "wednesday", "thursday", "friday", "saturday",
+         "sunday"], range(0, 7)))
+
+    new_start = week_start.lower()
+    if new_start not in weekdays:
+        return start_time
+    now = datetime.datetime.now()
+    offset = weekdays[new_start] - 7 * (weekdays[new_start] > now.weekday())
+    return start_time.replace(days=offset)
+
+
 def make_json_writer(func, *args, **kwargs):
     """
     Return a function that receives a file-like object and writes the return