Calc Relative Dates in Pwsh, using file modified dates

readme.md

Usage:

$minDate = [datetime]'2000-02-05'
$maxDate = [datetime]'2000-06-04'
$p1 = [datetime]'2000-04-04'
$p2 = [datetime]'2000-05-03'

TestDateTransform -Base $MinDate -Inp $P1

$file = gi $PSCommandPath
TestDateTransform -BaseDate '2024-03-02' -InputDate $file.LastWriteTime

Outputs

    Before                 RelativeTotalDays RelativeTotalMonths RelativeTo
    ------                 ----------------- ------------------- ----------
    2024-05-17 11:54:32 AM             76.50                2.55 2024-03-02 12:00:00 AM

# for a file with this date

    $file.LastWriteTime.ToString('o')
    2024-05-17T11:54:32.1282219-05:00


## final output

Before              : 2000-04-04 12:00:00 AM
RelativeTotalDays   : 59
RelativeTotalMonths : 1.96666666666667
RelativeTo          : 2000-02-05 12:00:00 AM
RenderMonth         : 1
RenderDay           : 29
RenderYear          : nyi
NewName             : nyi_1

Before              : 2024-05-17 11:54:32 AM
RelativeTotalDays   : 76.4962051877535
RelativeTotalMonths : 2.54987350625845
RelativeTo          : 2024-03-02 12:00:00 AM
RenderMonth         : 2
RenderDay           : 16
RenderYear          : nyi
NewName             : nyi_2

Calc Relative Dates in Pwsh.ps1

function CalcRelativeDays {
    param(
        [datetime]$BaseDate,
        [datetime]$InputDate,
        # default returns totalDays, this returns the raw [TimeSpan]
        [switch]$PassThru
    )
    if($PassThru){
        return ($InputDate - $BaseDate)
    }
    ($InputDate - $BaseDate).TotalDays
}

function TestDateTransform {
    param(
        [datetime]$BaseDate,
        [datetime]$InputDate
    )
    $rel_asTotalDays   = CalcRelativeDays -Base $BaseDate -Inp $InputDate # [int]
    $rel_asTotalMonths = ($rel_asTotalDays / 30) # [int] ($rel_asTotalDays / 30)

    # render names for filepaths. future: use a format string or zero pad values.
    $newMonth_str = [math]::floor( ($rel_asTotalDays / 30) )
    $newDay_str   = [math]::Round( $rel_asTotalDays % 30 )
    $newYear_str  = 'nyi'

    [pscustomobject]@{
        Before              = $InputDate
        RelativeTotalDays   = $rel_asTotalDays
        RelativeTotalMonths = $rel_asTotalMonths
        RelativeTo          = $BaseDate
        RenderMonth         = $newMonth_str
        RenderDay           = $newDay_str
        RenderYear = $newYear_str
        NewName             = @(
            $newYear_str
            $newMonth_str
            # $newDay_Str
        ) -join '_'
    }
}

$minDate = [datetime]'2000-02-05'
$maxDate = [datetime]'2000-06-04'
$p1 = [datetime]'2000-04-04'
$p2 = [datetime]'2000-05-03'

TestDateTransform -Base $MinDate -Inp $P1

$file = gi $PSCommandPath
TestDateTransform -BaseDate '2024-03-02' -InputDate $file.LastWriteTime