if (-not $IsWindows) {
    return
}

$GlobalGitConfig = Join-Path $HOME '.gitconfig'
$LocalGitConfig = Join-Path $HOME '.gitconfig.local'
$BackupPath = '{0}.pre-chezmoi.bak-{1}' -f $GlobalGitConfig, (Get-Date -Format 'yyyyMMdd-HHmmss')
$ManagedStub = @'
[include]
  path = ~/.config/git/config

[include]
  path = ~/.gitconfig.local
'@

$ManagedKeys = @(
    'core.autocrlf',
    'core.eol',
    'core.quotepath',
    'core.longpaths',
    'fetch.prune',
    'pull.ff',
    'init.defaultBranch'
)

function Test-ManagedGitStub {
    param(
        [Parameter(Mandatory = $true)]
        [string]$Content
    )

    $NormalizedContent = ($Content -replace "`r", '').Trim()
    $NormalizedStub = ($ManagedStub -replace "`r", '').Trim()
    return $NormalizedContent -eq $NormalizedStub
}

if (-not (Test-Path -LiteralPath $GlobalGitConfig)) {
    if (-not (Test-Path -LiteralPath $LocalGitConfig)) {
        New-Item -ItemType File -Path $LocalGitConfig -Force | Out-Null
    }
    return
}

$CurrentContent = Get-Content -LiteralPath $GlobalGitConfig -Raw
if (Test-ManagedGitStub -Content $CurrentContent) {
    if (-not (Test-Path -LiteralPath $LocalGitConfig)) {
        New-Item -ItemType File -Path $LocalGitConfig -Force | Out-Null
    }
    return
}

if (-not (Test-Path -LiteralPath $LocalGitConfig)) {
    Copy-Item -LiteralPath $GlobalGitConfig -Destination $BackupPath -Force
    Copy-Item -LiteralPath $GlobalGitConfig -Destination $LocalGitConfig -Force

    foreach ($Key in $ManagedKeys) {
        git config --file $LocalGitConfig --unset-all $Key 2>$null
    }

    Write-Host "Migrated existing ~/.gitconfig to ~/.gitconfig.local"
    Write-Host "Backup saved to: $BackupPath"
    return
}

Copy-Item -LiteralPath $GlobalGitConfig -Destination $BackupPath -Force
Write-Warning "~/.gitconfig.local already exists; current ~/.gitconfig was backed up before managed stub overwrite."
Write-Host "Backup saved to: $BackupPath"