# This script detects obsolete Playwright snapshots and automatically removes them.
# Obsolete snapshots are detected by re-generating the snapshots in a different folder and then
# comparing these two folders.
# To do this, we are taking advantage of the fact that development/pipeline snapshots
# are created using a Linux docker container, as we can re-generate the Playwright snapshots using
# the locally-installed version to have them automatically created in a separate folder (i.e. `linux` vs `windows`).
#
# This script will be required so long as Playwright does not have built-in functionality to detect and clean up
# obsolete snapshots.
# See: https://github.com/microsoft/playwright/issues/16582
#
# To run this script without removing an unused/obsolete snapshots and without removing the expected
# snapshots directory, please use the -dryRun parameter.

param(
    [string] $actualPath = "./tests/_snapshots/linux",
    [string] $expectedPath = "./tests/_snapshots/win32",
    [int] $maxAttempts = 5,
    [string] $dryRun = "no"
)

function Convert2Bool($this)
{
    return ($("False","0","","N","No",'$False',"Off") -notcontains [string]$this)
}

function EnforceWindowsOnlyExecution
{
    if(-not $IsWindows)
    {
        Write-Host -ForegroundColor Red "❌  This script can only be executed on Windows.";
        exit 1;
    }
}

function GenerateExpectedSnapshots([int] $maxAttempts)
{
    # Run Playwright to generate the expected snapshots
    $divider = "`n-------------------------------`n"
    Write-Host "$divider";
    $runTestsCommand = "npx playwright test --update-snapshots";
    $attemptsCount = 0;
    do
    {
        $attemptsCount++;

        Write-Host "Generating expected snapshots (attempt ${attemptsCount} / $maxAttempts)";
        Invoke-Expression -Command $runTestsCommand;
    } until ($LASTEXITCODE -eq 0 -or $attemptsCount -ge $maxAttempts);
    Write-Host "$divider";

    # Check if all attempts have failed
    if($LASTEXITCODE -ne 0)
    {
        Write-Host -ForegroundColor Red "❌  Failed to generate the expected snapshots after $attemptsCount attempts.";
        exit 1;
    }
}

function RemoveObsoleteSnapshots(
    [string] $actualPath,
    [string] $expectedPath,
    [bool] $dryRun)
{
    # Determine which files are unused
    Write-Host "Searching for unused snapshots"
    $actualContents = Get-ChildItem -Recurse -File -Path "$actualPath";
    $expectedContents = Get-ChildItem -Recurse -File -Path "$expectedPath";
    $diffResults = @(Compare-Object -PassThru -Property Name -ReferenceObject $expectedContents -DifferenceObject $actualContents);

    $hasUnusedSnapshots = $False;
    foreach($item in $diffResults)
    {
        # Reference Only   <=
        # Difference Only  =>
        if($item.SideIndicator -ne "=>")
        {
            continue;
        }

        # This file is an unused file (difference only)
        $fileFullPath = $item | Select-Object -ExpandProperty FullName;
        $fileRelativePath = $fileFullPath | Resolve-Path -Relative;
        $hasUnusedSnapshots = $True;
        if($dryRun)
        {
            Write-Host "* Unused snapshot detected: ${fileRelativePath}";
            continue;
        }

        Write-Host "* Deleting unused snapshot: ${fileRelativePath}";
        Remove-Item -Path $fileFullPath
    }

    if(-not $hasUnusedSnapshots)
    {
        Write-Host -ForegroundColor Yellow "No unused snapshots detected!";
    }
}

function RemoveEmptyDirectories(
    [string] $actualPath,
    [bool] $dryRun)
{
    if($dryRun) {
        Write-Host "Keeping empty directories (-dryRun specified)";
        return;
    }

    # Check if there are any empty folders and remove them
    Write-Host "Removing empty directories"
    Get-ChildItem $actualPath -Recurse -Force -Directory |
        Sort-Object -Property FullName -Descending |
        Where-Object { $($_ | Get-ChildItem -Force | Select-Object -First 1).Count -eq 0 } |
        Remove-Item;
}

function RemoveExpectedSnapshotsDirectory([string] $expectedPath)
{
    $expectedDirectoryExists = Test-Path -PathType Container -Path $expectedPath
    if(-not $expectedDirectoryExists)
    {
        Write-Host -ForegroundColor Yellow "Expected snapshots directory does not exist, skipping removal";
        return;
    }

    # Remove the expected snapshots directory
    Write-Host "Removing expected snapshots directory";
    Remove-Item -Recurse -Path $expectedPath;
}

function Main
{
    $ErrorActionPreference = 'Stop'
    $dryRunAsBool = Convert2Bool($dryRun);

    EnforceWindowsOnlyExecution;
    RemoveExpectedSnapshotsDirectory -expectedPath $expectedPath; # Clean expected folder before starting
    GenerateExpectedSnapshots -maxAttempts $maxAttempts;
    RemoveObsoleteSnapshots -actualPath $actualPath -expectedPath $expectedPath -dryRun $dryRunAsBool;
    RemoveEmptyDirectories -actualPath $actualPath -dryRun $dryRunAsBool; # Remove empty directories in the $actualPath folder
    RemoveExpectedSnapshotsDirectory -expectedPath $expectedPath; # Also clean expected folder after completion

    Write-Host -ForegroundColor Green "✅  Finished cleaning playwright snapshots";
}

Main;