[CmdletBinding()]
param(
    [Parameter(Mandatory = $true)]
    [string]$BackupDirectory
)

$ErrorActionPreference = "Stop"
$target = (Resolve-Path -LiteralPath $BackupDirectory).Path
$requiredFiles = @(
    "SHA256SUMS",
    "postgres.dump",
    "postgres.contents",
    "minio-data.tar.gz",
    "manifest.txt"
)
foreach ($file in $requiredFiles) {
    if (-not (Test-Path -LiteralPath (Join-Path $target $file) -PathType Leaf)) {
        throw "备份缺少文件：$file"
    }
}

foreach ($line in Get-Content -LiteralPath (Join-Path $target "SHA256SUMS")) {
    if ($line -notmatch "^([0-9a-fA-F]{64})\s{2}(.+)$") {
        throw "SHA256SUMS 格式无效：$line"
    }
    $expected = $Matches[1].ToLowerInvariant()
    $file = $Matches[2]
    $path = Join-Path $target $file
    if (-not (Test-Path -LiteralPath $path -PathType Leaf)) {
        throw "校验文件不存在：$file"
    }
    $actual = (Get-FileHash -Algorithm SHA256 -LiteralPath $path).Hash.ToLowerInvariant()
    if ($actual -ne $expected) {
        throw "备份校验失败：$file"
    }
}

Write-Output "备份校验通过：$target"