Tasks filtering by start date and by due date, and their ordering

[yvolk]

The thread continues plusonelabs#356 where @shompoe noted that in current implementation of tasks we filter out and sort tasks by due dates, but start dates don't get needed attention.

As a result of discussion we came to the below lists of sample tasks, presented so that it would be easier to understand, what is shown and where (if not obvious...).
The tasks are sorted in a way they should be sorted in the widget (assuming initially they are sorted according to their numbers)

For which events/tasks	Filter settings
For past events	"Show past events ended today" is on
For current and future events	Date range: One month

New option introduced:
"Task scheduling" (What date gets main attention for a task) with two values:
T1. Show tasks under date due (Due date gets main attention, and we are showing tasks at their due dates, where it makes sense).
T2. Show tasks under date started (Start date gets main attention, and we are showing tasks at their start dates, where it makes sense).

In any case both start and due dates are taken into account, but differently.

task9 and task10 below (as other tasks without start and due dates) need special treatment i.e. additional option:
"Tasks without start and due dates" with values:
.1 Show at the end of the whole list (default option)
.2 Show at the end of Today.
.3 Hide.
Below tables are shown with default option

Task visibility and sorting if option T1 (Due date...) is selected:

Task description	Show	Where to show
task11 starting last month (after task5) and due last week (at the same time as task5) (complete)	no
task5 starting last month and due last week (incomplete)	yes	Last week (or "Past and Due" if turned on. The same for others in the past)
task3 without start date and due later today at 9PM (incomplete)	yes	Today or at 9PM
task1 starting last week and due later today at 10PM (incomplete)	yes	Today at 10PM
task6 starting last month and due tomorrow at 8AM (complete)	no
task7 starting today at 8AM and due tomorrow at 9AM (complete)	no
task12 starting today at 7AM and due tomorrow at 10AM (incomplete)	yes	at due date: Tomorrow at 10AM
task17 starting in 10 days, without due date (incomplete)	yes	At start date
task16 without start date and due in 20 days	yes	At due date
		End of list header
task14 starting in 39 days, and without due date (incomplete)	no
task8 starting next week, due in 41 days (incomplete)	yes	End of list, closer to due date
task4 without start date and due in 42 days (incomplete)	no
task2 starting last week and due in 43 days (incomplete)	yes	End of list
task15 starting in 40 days, due in 45 days (incomplete)	no
task10 without start date and without due date (incomplete)	yes	(Position depends on "Tasks without start and due dates")
task9 without start date and without due date (complete)	no	(Position depends on "Tasks without start and due dates")

Task visibility and sorting if option T2 (Start date...) is selected:

Task description	Show	Where to show
task11 starting last month (after task5) and due last week (at the same time as task5) (complete)	no
task5 starting last month and due last week (incomplete)	yes	Last week (or "Past and Due" if turned on. The same for others in the past)
task3 without start date and due later today at 9PM (incomplete)	yes	Start of today
task1 starting last week and due later today at 10PM (incomplete)	yes	Start of Today
task6 starting last month and due tomorrow at 8AM (complete)	no
task16 without start date and due in 20 days	yes	Start of today
task4 without start date and due in 42 days (incomplete)	yes	Start of today
task2 starting last week and due in 43 days (incomplete)	yes	Start of Today
task12 starting today at 7AM and due tomorrow at 10AM (incomplete)	yes	Today at 7AM
task7 starting today at 8AM and due tomorrow at 9AM (complete)	no
task8 starting next week, due in 41 days (incomplete)	yes	Next week
task17 starting in 10 days, without due date (incomplete)	yes	At start date
		End of list header
task14 starting in 39 days, and without due date (incomplete)	no
task15 starting in 40 days, due in 45 days (incomplete)	no
task10 without start date and without due date (incomplete)	yes	(Position depends on "Tasks without start and due dates")
task9 without start date and without due date (complete)	no	(Position depends on "Tasks without start and due dates")

[yvolk]

Implemented, the latest Alpha build 4.0.1 is here: #3

This build allows you, in particular, to play with exactly those content (plus some calendars events...) that is now in T1 and T2 tables: just goto to Settings -> Feedback and Backup -> Restore settings from a backup -> and restore this file with settings and events (unzip it first manually!):
filter_tasks_308_no_filters.zip

[yvolk]

Released in v.4.0.6