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

$ErrorActionPreference = 'Stop'
$source = [System.IO.Path]::GetFullPath($BackupDirectory)
$manifest = Get-Content (Join-Path $source 'manifest.json') | ConvertFrom-Json
foreach ($file in @('postgres.dump', 'redis.rdb', 'tdlib-data.tar.gz')) {
  $actual = (Get-FileHash -Algorithm SHA256 (Join-Path $source $file)).Hash
  if ($actual -ne $manifest.sha256.$file) {
    throw "Checksum mismatch: $file"
  }
}

$postgresContainer = 'tgw-restore-postgres'
$redisContainer = 'tgw-restore-redis'
$filesVolume = 'tgw_restore_files'

function Remove-TestResources {
  $containerNames = @(docker ps -a --format '{{.Names}}')
  if ($containerNames -contains $postgresContainer) {
    docker rm -f $postgresContainer | Out-Null
  }
  if ($containerNames -contains $redisContainer) {
    docker rm -f $redisContainer | Out-Null
  }
  $volumeNames = @(docker volume ls --format '{{.Name}}')
  if ($volumeNames -contains $filesVolume) {
    docker volume rm $filesVolume | Out-Null
  }
}

try {
  Remove-TestResources

  docker run -d --name $postgresContainer -e POSTGRES_PASSWORD=restore-test `
    -e POSTGRES_DB=telegram_gateway_restore postgres:16-alpine | Out-Null
  $postgresReady = $false
  for ($attempt = 0; $attempt -lt 30; $attempt++) {
    docker exec $postgresContainer pg_isready -U postgres -d telegram_gateway_restore 2>$null | Out-Null
    if ($LASTEXITCODE -eq 0) {
      $postgresReady = $true
      break
    }
    Start-Sleep -Seconds 1
  }
  if (-not $postgresReady) {
    throw 'Isolated PostgreSQL restore container did not become ready'
  }

  docker cp (Join-Path $source 'postgres.dump') "${postgresContainer}:/tmp/gateway.dump"
  docker exec $postgresContainer pg_restore -U postgres -d telegram_gateway_restore /tmp/gateway.dump
  $tables = [int](docker exec $postgresContainer psql -U postgres -d telegram_gateway_restore -Atc `
    "select count(*) from information_schema.tables where table_schema='public';")
  $tenants = [int](docker exec $postgresContainer psql -U postgres -d telegram_gateway_restore -Atc `
    'select count(*) from tenants;')
  $accounts = [int](docker exec $postgresContainer psql -U postgres -d telegram_gateway_restore -Atc `
    'select count(*) from tg_accounts;')
  if ($tables -ne [int]$manifest.expected.publicTables -or
      $tenants -ne [int]$manifest.expected.tenantRows -or
      $accounts -ne [int]$manifest.expected.accountRows) {
    throw "PostgreSQL restore count mismatch"
  }

  docker create --name $redisContainer redis:7-alpine | Out-Null
  docker cp (Join-Path $source 'redis.rdb') "${redisContainer}:/data/dump.rdb"
  docker run --rm -v "${source}:/backup:ro" redis:7-alpine `
    redis-check-rdb /backup/redis.rdb | Out-Null
  if ($LASTEXITCODE -ne 0) {
    throw 'Redis RDB integrity check failed'
  }
  docker start $redisContainer | Out-Null
  $redisReady = $false
  for ($attempt = 0; $attempt -lt 20; $attempt++) {
    $ping = docker exec $redisContainer redis-cli PING 2>$null
    if ($ping -eq 'PONG') {
      $redisReady = $true
      break
    }
    Start-Sleep -Milliseconds 500
  }
  if (-not $redisReady) {
    throw 'Isolated Redis restore container did not become ready'
  }
  $redisSize = [int](docker exec $redisContainer redis-cli DBSIZE)
  # BullMQ keys have TTLs and may legitimately expire between SAVE and this
  # isolated restore. The RDB checksum/load must succeed and the restored key
  # count must never exceed the snapshot-time upper bound.
  if ($redisSize -gt [int]$manifest.expected.redisDbSize) {
    throw "Redis restore produced more keys than the snapshot"
  }

  docker volume create $filesVolume | Out-Null
  docker run --rm -v "${filesVolume}:/restore" -v "${source}:/backup:ro" `
    node:20-bookworm-slim `
    tar -xzf /backup/tdlib-data.tar.gz -C /restore
  $fileCount = [int](docker run --rm -v "${filesVolume}:/restore:ro" `
    node:20-bookworm-slim sh -c `
    "find /restore/tdlib_data /restore/uploads -type f 2>/dev/null | wc -l")
  if ($fileCount -ne [int]$manifest.expected.tdlibFileCount) {
    throw "TDLib/uploads restore file count mismatch"
  }

  Write-Output (
    "restore_verified tables=$tables tenants=$tenants accounts=$accounts " +
    "redis_keys=$redisSize redis_snapshot_max=$($manifest.expected.redisDbSize) " +
    "files=$fileCount checksums=ok"
  )
} finally {
  Remove-TestResources
}