Import-Module PSCache

# Define fetcher
$Fetcher = {
    # Emulate a potentially slow operation
    Start-Sleep -Milliseconds (Get-Random -Minimum 15 -Maximum 30)

    # Return an object corresponding to $_
    [pscustomobject]@{
        ID   = $_
        Data = "SomeValue${_}"
    }
}

# Create PSCache instance with LRU policy
$LRUcache  = New-PSCache -Fetcher $Fetcher -EvictionPolicy LRU -Capacity 100

# Create PSCache instance with LFU policy
$LFUcache  = New-PSCache -Fetcher $Fetcher -EvictionPolicy LFU -Capacity 100

# Create PSCache instance with Segmented LRU policy
$SLRUcache = New-PSCache -Fetcher $Fetcher -EvictionPolicy SLRU -Capacity 50

# Prepare our access pattern
$IDs = 1..1000 |ForEach-Object {
    1..200 |Get-Random
}

# Without Caching
Write-Host "Testing semi-random access pattern:" -ForegroundColor Green
Measure-Command {
    $IDs |ForEach-Object -Process $Fetcher
} |Select-Object @{N='Strategy';E={'No Cache'}},TotalSeconds

# With LRU
Measure-Command {
    $IDs |ForEach-Object {
        $LRUcache.Get($_)
    }
} |Select-Object @{N='Strategy';E={'Evict Least-Recently Used'}},TotalSeconds

# With LFU
Measure-Command {
    $IDs |ForEach-Object {
        $LFUcache.Get($_)
    }
} |Select-Object @{N='Strategy';E={'Evict Least-Frequently Used'}},TotalSeconds

# With SLRU
Measure-Command {
    $IDs |ForEach-Object {
        $SLRUcache.Get($_)
    }
} |Select-Object @{N='Strategy';E={'Evict Segmented LRU'}},TotalSeconds