get-pairs-sequencially

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sidebar_position: 7

getPairsSequentially Function

Overview

The getPairsSequentially function processes a list of attendance log entries, identifies valid intervals of check-ins and check-outs based on provided duration and threshold criteria, and returns a structured result containing these intervals.

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Function Signature

func getPairsSequentially(scanLogs []*entity.AttendanceLogTable, duration, treshold float64) IntervalPairs

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Parameters

Parameter	Type	Description
scanLogs	[]*entity.AttendanceLogTable	List of attendance log entries, each containing a timestamp.
duration	float64	Minimum allowed interval duration (in minutes) between a check-in and check-out.
treshold	float64	Minimum gap duration (in minutes) required between intervals to consider them as separate.

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Return Value

• 
  Type: IntervalPairsA collection of interval structures representing valid check-in and check-out pairs along with metadata.

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Detailed Logic

1. Initialization

• Create an empty list of raw pairs (rawPairs) to hold potential interval pairs.
• Start with the first log as the initial reference (rawPair and lastOne).

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2. Pairing Logic

• Iterate through scanLogs:

  1. Parse timestamps of the current and previous logs (scan.Timestamp and lastOne.Timestamp).
  2. Calculate the time gap (gapDuration) between them.
  3. Add to rawPair if:
     • The gapDuration meets the duration criteria for appending to an existing pair.
     • The gapDuration meets the treshold criteria for starting a new pair.
  4. Append completed rawPair to rawPairs when conditions are met, and reset rawPair.

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3. Processing Intervals

• For each raw pair:

  1. Validate that it contains exactly two entries (check-in and check-out).
  2. Calculate the interval duration between check-in and check-out timestamps.
  3. Create IntervalDuration objects for check-in (ci) and check-out (co).
  4. Create an Intervals object containing:
     • Metadata such as index, timestamps, duration, and calculation status.
     • Flags for whether the entry is the first or last in the sequence.
  5. Apply additional validation:
     • Mark intervals as invalid if the duration is below duration or the gap is below treshold.

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4. Flags and Results

• Mark the first valid interval as the first check-in (ci.First = true).
• Mark the last valid interval as the last check-out (co.Last = true).
• Append valid intervals to results.

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Example Use Case

Input

scanLogs := []*entity.AttendanceLogTable{
    {Timestamp: "2024-12-10T08:00:00Z"},
    {Timestamp: "2024-12-10T12:00:00Z"},
    {Timestamp: "2024-12-10T18:00:00Z"},
}
duration := 180.0  // 3 hours
treshold := 30.0   // 30 minutes

Output

The function returns a structured IntervalPairs object containing valid check-in and check-out intervals based on the provided criteria.

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Key Structs and Enums

IntervalPairs

A collection of Intervals objects.

Intervals

Field	Type	Description
Index	int	Index of the interval in the sequence.
Ci	*IntervalDuration	Metadata for the check-in log.
Co	*IntervalDuration	Metadata for the check-out log.
CiTime	string	Timestamp of the check-in log.
CoTime	string	Timestamp of the check-out log.
Duration	float64	Interval duration (in minutes).
IsCalculated	bool	Whether the interval meets calculation criteria.
CalculatedReason	string	Reason why the interval was invalid, if applicable.

IntervalDuration

Field	Type	Description
Log	*entity.AttendanceLogTable	Reference to the log entry.
Candidate	string	Type of log ("ci" for check-in, "co" for check-out).
DurationToNext	float64	Duration to the next interval, for check-ins.
PrevDuration	float64	Duration to the previous interval, for check-outs.
IntervalNum	int	Interval index in the sequence.

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Notes

• Edge Cases:
  • Ensure scanLogs is not empty to avoid processing errors.
  • Handle cases where intervals overlap or fail validation due to duration or gap criteria.
• Performance:
  • Efficiently manages memory by modifying scanLogs in place.
  • Uses sequential processing to maintain order.

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