Struggling with logic for checking consecutive data entries - php

Question

I'm trying to figure out how to handle a tricky little situation I've found myself in this morning. I have an entries table in my database where I store details about users' monthly entries (information capture stuff) - I want to increment the number (not the ID) of each entry once a month has passed. The idea is to use the "number" field to be able to identify consecutive monthly entries and to disregard entries within close proximity to one another.
When a user visits the site to start a new entry, I check the date of the last entry completed to see if it is more than 21 days ago (which qualifies as being a valid month) then I increment the "number" for this new entry. The problem is that I can end up with a sequence of entries which are all less than 21 days apart (and thus all have the same number), but collectively span more than 21 days! I need to be able to find some logic to handle this - anyone have any ideas?
An example of how this data is stored, and the problem I'm having, can be seen below.
+------+--------+------------+------------+----------------------------+
| id | number | initiated | updated | last_category_reached |
+------+--------+------------+------------+----------------------------+
| 4 | 1 | 1277914181 | 1277914320 | complete |
| 105 | 2 | 1282639343 | 1283444717 | complete |
| 397 | 3 | 1284999429 | 1285001298 | complete |
| 404 | 3 | 1287478550 | 1287478631 | complete |
| 636 | 3 | 1287479243 | 1287479377 | complete |
| 649 | 3 | 1287581361 | 1287581466 | complete |
| 652 | 3 | 1287585123 | 1287585365 | complete |
| 656 | 3 | 1290185205 | 1290424128 | complete |
| 1105 | 3 | 1292421193 | 1292426686 | complete |
| 1106 | 3 | 1292426769 | 1292426870 | complete |
+------+--------+------------+------------+----------------------------+
My php logic is below...
public function update_entry($stage = NULL)
{
// Get last number entered for this user
$last_entry = $this->last_entry();
// If part one, user profile is calling the update (passing the next stage as a param)
if ($stage === 'user/profile/2?s=p_prof&p=2')
{
// Only at this stage do we ever create a new entry
$entry = ORM::factory('data_entry');
// If no previous sessions, start from 1
if ($last_entry === FALSE)
$num = 1;
//Here we need to check the time period elapsed since the last submission
else
{
// Check if time difference between last visit and current time is less than 49 days and more than 21 days
if (($last_entry->initiated > time() - 4233600) && ($last_entry->initiated < time() - 1814400))
{
// Within allowed timeframe, ok to increment by one as a new entry
$num = $last_entry->number + 1;
}
// More than 49 days since last visit
elseif (($last_entry->initiated < time() - 4233600))
{
// Increment by two to break consecutive entries
$num = $last_entry->number + 2;
}
// Entry is within the last 21 days - if user never finished stages, use last entry created instead of creating a new one
else
{
// If they are back at the start having completed a full entry the last time, ok to create a new entry - otherwise use the one created the last time
if ($last_entry->last_category_reached !== 'complete')
$entry = $last_entry;
$num = $last_entry->number;
}
}
// Save the rest of the data for a new entry
$entry->number = $num;
$entry->initiated = time();
$entry->updated = time();
$entry->last_category_reached = $stage;
$entry->user_id = $this->id;
$entry->save();
}
// If it's been more than 49 days since last part completion of an entry, user won't be given option to finish the entry, so no need for time check here
elseif ($stage !== NULL)
{
// This must be a continuation of a form, not the beginning of a new one
// Just update the stage reached and save
$last_entry->last_category_reached = $stage;
$last_entry->updated = time();
$last_entry->save();
// Assign to $entry for return
$entry = $last_entry;
}
return $entry;
}
/**
* Returns the the last data entry session
* #return
*/
public function last_entry()
{
return $this
->limit(1)
->data_entries
->current();
}

Answer 1

What I would do in pseudo-code :
If there is a previous number, take the entry with max(number) and min(id).
Calculate the delay between the time of this entry and the current time.
If it is less than 21 days, I don't change numbers, if it's more, I change number.
If you apply this, you won't get periods that last more than 21 days.