param(
  [string]$OldNamespace = "ircs-system",
  [string]$NewNamespace = "ircs-prod",
  [string]$Database = "ircs",
  [switch]$Execute,
  [switch]$TruncateTarget
)

$ErrorActionPreference = "Stop"

$tables = @(
  'actors', 'collection_tasks', 'cover_images', 'data_sources', 'directors', 'episodes',
  'failed_messages', 'magnet_links', 'magnet_provider_runs', 'magnet_providers', 'magnet_search_jobs',
  'member_favorites', 'member_watch_histories', 'members', 'playlists', 'raw_areas', 'raw_category',
  'raw_genres', 'raw_languages', 'raw_video_unified_video', 'raw_videos', 'request_audit_logs',
  'search_sync_tasks', 'source_domains', 'standard_areas', 'standard_category', 'standard_genre',
  'standard_languages', 'sys_credentials', 'system_configs', 'unified_video_actors',
  'unified_video_directors', 'unified_video_genres', 'unified_video_standard_areas',
  'unified_video_standard_languages', 'unified_videos', 'user_messages', 'video_actors',
  'video_directors', 'video_raw_areas', 'video_raw_genres', 'video_raw_languages',
  'video_resolver_sources'
)

function Invoke-Postgres($Namespace, $Sql) {
  $escapedSql = $Sql.Replace("'", "'\''")
  kubectl -n $Namespace exec statefulset/postgres -- sh -lc "PGPASSWORD=\`$POSTGRES_PASSWORD psql -U postgres -d $Database -Atc '$escapedSql'"
}

function Get-TableColumns($Namespace, $TableName) {
  $sql = "select column_name || '|' || udt_name || '|' || is_nullable || '|' || coalesce(column_default, '') from information_schema.columns where table_schema='public' and table_name='$TableName' order by ordinal_position"
  $lines = @(Invoke-Postgres $Namespace $sql)
  $columns = @()
  foreach ($line in $lines) {
    if (-not $line) { continue }
    $parts = $line -split '\|', 4
    $columns += [pscustomobject]@{
      Name = $parts[0]
      UdtName = $parts[1]
      Nullable = $parts[2]
      Default = if ($parts.Count -ge 4) { $parts[3] } else { '' }
    }
  }
  return $columns
}

Write-Host "Compatible business tables planned for migration: $($tables.Count)"
Write-Host "Excluded tables: databasechangelog, databasechangeloglock, V3 runtime audit/outbox/maintenance derived tables."

$oldTables = Invoke-Postgres $OldNamespace "select tablename from pg_tables where schemaname='public' order by tablename"
$newTables = Invoke-Postgres $NewNamespace "select tablename from pg_tables where schemaname='public' order by tablename"
$missingOld = $tables | Where-Object { $_ -notin $oldTables }
$missingNew = $tables | Where-Object { $_ -notin $newTables }
if ($missingOld) { throw "Old namespace is missing expected tables: $($missingOld -join ', ')" }
if ($missingNew) { throw "New namespace is missing expected tables. Run ircs-prod core migrator first: $($missingNew -join ', ')" }

$schemaIssues = @()
foreach ($table in $tables) {
  $oldColumns = @(Get-TableColumns $OldNamespace $table)
  $newColumns = @(Get-TableColumns $NewNamespace $table)
  $newByName = @{}
  foreach ($column in $newColumns) {
    $newByName[$column.Name] = $column
  }
  $oldByName = @{}
  foreach ($column in $oldColumns) {
    $oldByName[$column.Name] = $column
    if (-not $newByName.ContainsKey($column.Name)) {
      $schemaIssues += "${table}: old column '$($column.Name)' is missing in target"
      continue
    }
    $target = $newByName[$column.Name]
    if ($column.UdtName -ne $target.UdtName) {
      $schemaIssues += "$table.$($column.Name): type mismatch old=$($column.UdtName) new=$($target.UdtName)"
    }
  }
  foreach ($column in $newColumns) {
    if (-not $oldByName.ContainsKey($column.Name) -and $column.Nullable -eq 'NO' -and -not $column.Default) {
      $schemaIssues += "${table}: target required column '$($column.Name)' has no old value and no default"
    }
  }
}

if ($schemaIssues.Count -gt 0) {
  $schemaIssues | ForEach-Object { Write-Host "SCHEMA ISSUE: $_" }
  throw "Schema preflight failed with $($schemaIssues.Count) issue(s)."
}

Write-Host "Schema preflight passed for $($tables.Count) compatible business tables."

if (-not $Execute) {
  Write-Host "Dry run only. Add -Execute to stream data from $OldNamespace to $NewNamespace."
  exit 0
}

if ($TruncateTarget) {
  $quoted = ($tables | ForEach-Object { 'public."' + $_ + '"' }) -join ', '
  Invoke-Postgres $NewNamespace "truncate table $quoted restart identity cascade" | Out-Null
}

$tableArgs = ($tables | ForEach-Object { "--table=public.$_" }) -join ' '
$dumpCmd = "PGPASSWORD=\`$POSTGRES_PASSWORD pg_dump -U postgres -d $Database --data-only --column-inserts --disable-triggers $tableArgs"
$loadCmd = "PGPASSWORD=\`$POSTGRES_PASSWORD psql -U postgres -d $Database -v ON_ERROR_STOP=1"

kubectl -n $OldNamespace exec statefulset/postgres -- sh -lc $dumpCmd | kubectl -n $NewNamespace exec -i statefulset/postgres -- sh -lc $loadCmd
Write-Host "Compatible data migration stream finished."