[CmdletBinding()]
param(
    [Parameter(Mandatory)][ValidatePattern('^[0-9a-fA-F-]{36}$')][string]$SourceEndpointId,
    [Parameter(Mandatory)][string]$FromNodeId,
    [Parameter(Mandatory)][string]$ToNodeId,
    [Parameter(Mandatory)][string]$ReadyMarker,
    [Parameter(Mandatory)][string]$StartMarker,
    [Parameter(Mandatory)][string]$OutputDirectory,
    [string]$CoordinatorUrl = 'http://127.0.0.1:18100',
    [string]$CredentialFile = (Join-Path (Split-Path -Parent $PSScriptRoot) 'runtime/cluster.local.properties'),
    [ValidateRange(1,300)][int]$WaitSeconds = 90,
    [ValidateRange(1,3600)][int]$DurationSeconds = 25
)
$ErrorActionPreference = 'Stop'
$readyPath = [IO.Path]::GetFullPath($ReadyMarker)
$startPath = [IO.Path]::GetFullPath($StartMarker)
[void][IO.Directory]::CreateDirectory([IO.Path]::GetDirectoryName($readyPath))
$readyAt = [DateTimeOffset]::UtcNow.ToUnixTimeMilliseconds()
$requestId = [Guid]::NewGuid().ToString()
# 只保存随机门闩与公开业务标识，文件中没有集群密钥、浏览器会话或图片访问地址。
$ready = [ordered]@{ requestId = $requestId; endpointId = $SourceEndpointId; fromNodeId = $FromNodeId
    toNodeId = $ToNodeId; readyAtMs = $readyAt }
[IO.File]::WriteAllText($readyPath, ($ready | ConvertTo-Json -Compress), [Text.UTF8Encoding]::new($false))
Write-Output '迁移脚本已等待前端采样启动信号，尚未改容量。'
$deadline = [DateTimeOffset]::UtcNow.AddSeconds($WaitSeconds)
$started = $false
while ([DateTimeOffset]::UtcNow -lt $deadline) {
    if (Test-Path -LiteralPath $startPath) {
        try {
            $marker = [IO.File]::ReadAllText($startPath) | ConvertFrom-Json
            $now = [DateTimeOffset]::UtcNow.ToUnixTimeMilliseconds()
            # 匹配本次随机门闩，并要求浏览器采样已开始、时间新鲜，旧文件不能触发迁移。
            if ($marker.requestId -eq $requestId -and $marker.endpointId -eq $SourceEndpointId -and
                [long]$marker.startedAtMs -ge $readyAt -and [long]$marker.startedAtMs -le $now + 1000 -and
                $now - [long]$marker.startedAtMs -le 5000) { $started = $true; break }
        } catch { }
    }
    Start-Sleep -Milliseconds 100
}
if (-not $started) { throw '前端采样启动信号等待超时，未修改容量。' }
Write-Output '前端采样启动信号已匹配，开始已授权的原图迁移。'
& (Join-Path $PSScriptRoot 'Observe-OriginalImage.ps1') -CoordinatorUrl $CoordinatorUrl -CredentialFile $CredentialFile `
    -SourceEndpointId $SourceEndpointId -FromNodeId $FromNodeId -ToNodeId $ToNodeId -Migrate -QuietFrames `
    -DurationSeconds $DurationSeconds -PollMilliseconds 200 -OutputDirectory $OutputDirectory