$ErrorActionPreference = 'Stop'
. (Join-Path $PSScriptRoot 'campaign-common.ps1')

function Enter-DispatchLock {
    param([int]$WaitMilliseconds = 0)
    $folder = Join-Path (Split-Path -Parent $PSScriptRoot) 'temp'
    if (-not (Test-Path -LiteralPath $folder -PathType Container)) {
        $null = New-Item -ItemType Directory -Path $folder -Force
    }
    $path = Join-Path $folder 'dispatch.lock'
    $deadline = [DateTime]::UtcNow.AddMilliseconds($WaitMilliseconds)
    while ($true) {
        try {
            return [System.IO.File]::Open($path, [System.IO.FileMode]::OpenOrCreate,
                [System.IO.FileAccess]::ReadWrite, [System.IO.FileShare]::None)
        }
        catch [System.IO.IOException] {
            if ([DateTime]::UtcNow -ge $deadline) {
                throw 'Another dispatch or campaign control action is still running'
            }
            Start-Sleep -Milliseconds 250
        }
    }
}

function Get-QueueInterval {
    param($Context)
    $interval = 0
    if (-not [int]::TryParse($Context.Settings['QUEUE_INTERVAL'], [ref]$interval) -or
        $interval -lt 60 -or $interval -gt 86400) {
        throw 'QUEUE_INTERVAL must be 60-86400 seconds'
    }
    return $interval
}

function Get-ReviewHours {
    param($Context)
    $hours = 0
    if (-not [int]::TryParse($Context.Settings['OPT_OUT_REVIEW_HOURS'], [ref]$hours) -or
        $hours -lt 1 -or $hours -gt 168) {
        throw 'OPT_OUT_REVIEW_HOURS must be 1-168'
    }
    return $hours
}

function Get-OperationalState {
    param($Connection, $Transaction = $null)
    $command = New-DbCommand $Connection 'SELECT [GlobalPause],[LastOptOutReviewAtUtc] FROM [OperationalState] WHERE [Id]=1' $Transaction
    $reader = $command.ExecuteReader()
    try {
        if (-not $reader.Read()) { throw 'OperationalState row is missing' }
        $reviewed = if ($reader.IsDBNull(1)) { $null } else { [DateTime]$reader.GetValue(1) }
        return @{ Paused = [bool]$reader.GetValue(0); Reviewed = $reviewed }
    }
    finally { $reader.Dispose() }
}

function Assert-OptOutReviewCurrent {
    param($Context, $State)
    $hours = Get-ReviewHours $Context
    if ($null -eq $State.Reviewed -or $State.Reviewed -lt [DateTime]::UtcNow.AddHours(-$hours)) {
        throw 'Review the reply mailbox and record opt-outs before sending'
    }
}

function Get-DispatchClock {
    param($Connection, [string]$SenderKey, [int]$Interval, $Transaction = $null)
    $command = New-DbCommand $Connection 'SELECT [LastAttemptAtUtc],[NextAllowedAttemptUtc] FROM [DispatchState] WHERE [SenderKey]=?' $Transaction
    Add-TextParameter $command 'sender' 254 $SenderKey
    $reader = $command.ExecuteReader()
    try {
        if (-not $reader.Read()) { return @{ Exists = $false; Last = $null; Next = $null } }
        $last = if ($reader.IsDBNull(0)) { $null } else { [DateTime]$reader.GetValue(0) }
        $next = if ($reader.IsDBNull(1)) { $null } else { [DateTime]$reader.GetValue(1) }
    }
    finally { $reader.Dispose() }
    if ($null -ne $last) {
        $newGap = $last.AddSeconds($Interval)
        if ($null -eq $next -or $newGap -gt $next) { $next = $newGap }
    }
    return @{ Exists = $true; Last = $last; Next = $next }
}

function Assert-OpenHtaSession {
    param([int]$HtaPid, [string]$Token)
    if ($HtaPid -lt 1 -or $Token -notmatch '^[0-9a-f]{32}$') { throw 'Missing HTA session token' }
    $path = Join-Path (Split-Path -Parent $PSScriptRoot) "temp\session-$HtaPid.txt"
    if (-not (Test-Path -LiteralPath $path -PathType Leaf)) { throw 'HTA session is closed' }
    $file = Get-Item -LiteralPath $path
    if ($file.LastWriteTimeUtc -lt [DateTime]::UtcNow.AddSeconds(-20) -or
        ([System.IO.File]::ReadAllText($path)).Trim() -ne $Token) {
        throw 'HTA session heartbeat is stale'
    }
    $process = Get-WmiObject Win32_Process -Filter "ProcessId=$HtaPid" -ErrorAction Stop
    if (-not $process -or $process.Name -ne 'mshta.exe' -or
        $process.CommandLine -notmatch '(?i)MassMailer\.hta') {
        throw 'HTA process is not running'
    }
}

function Get-DeliverySnapshot {
    param($Connection, [int]$DeliveryId)
    $sql = 'SELECT d.[EmailKey],c.[EmailOriginal],m.[FromSnapshot],m.[ReplyToSnapshot],m.[PostalAddressSnapshot],m.[Subject],m.[TemplateVersionId],m.[Status] FROM ([Delivery] AS d INNER JOIN [Contact] AS c ON d.[ContactId]=c.[Id]) INNER JOIN [Campaign] AS m ON d.[CampaignId]=m.[Id] WHERE d.[Id]=?'
    $command = New-DbCommand $Connection $sql
    $null = $command.Parameters.Add('id', [System.Data.OleDb.OleDbType]::Integer)
    $command.Parameters[0].Value = $DeliveryId
    $reader = $command.ExecuteReader()
    try {
        if (-not $reader.Read()) { throw 'Reserved delivery is missing' }
        $emailKey = [string]$reader.GetValue(0)
        $address = [string]$reader.GetValue(1)
        if ($emailKey -ne $address.ToLowerInvariant()) { throw 'Contact email changed after approval' }
        return @{ EmailKey = $emailKey; Email = $address; From = [string]$reader.GetValue(2);
            ReplyTo = [string]$reader.GetValue(3); Postal = [string]$reader.GetValue(4);
            Subject = [string]$reader.GetValue(5); TemplateId = [int]$reader.GetValue(6);
            CampaignStatus = [string]$reader.GetValue(7) }
    }
    finally { $reader.Dispose() }
}

function Get-ApprovedCampaignSnapshot {
    param($Connection, [int]$CampaignId)
    $command = New-DbCommand $Connection 'SELECT [FromSnapshot],[ReplyToSnapshot],[PostalAddressSnapshot],[Subject],[TemplateVersionId],[Status] FROM [Campaign] WHERE [Id]=?'
    $null = $command.Parameters.Add('id', [System.Data.OleDb.OleDbType]::Integer)
    $command.Parameters[0].Value = $CampaignId
    $reader = $command.ExecuteReader()
    try {
        if (-not $reader.Read()) { throw 'Approved campaign was not found' }
        $status = [string]$reader.GetValue(5)
        if ($status -notin @('approved_paused','running')) {
            throw 'Campaign is not approved and active'
        }
        return @{ From = [string]$reader.GetValue(0); ReplyTo = [string]$reader.GetValue(1);
            Postal = [string]$reader.GetValue(2); Subject = [string]$reader.GetValue(3);
            TemplateId = [int]$reader.GetValue(4) }
    }
    finally { $reader.Dispose() }
}

function Test-Suppressed {
    param($Connection, [string]$EmailKey, $Transaction = $null)
    $command = New-DbCommand $Connection 'SELECT COUNT(*) FROM [Suppression] WHERE [EmailKey]=?' $Transaction
    Add-TextParameter $command 'key' 254 $EmailKey
    return [int]$command.ExecuteScalar() -gt 0
}

function Complete-DeliveryAttempt {
    param($Connection, [int]$DeliveryId, [int]$AttemptId,
        [string]$Outcome, [string]$Status, [string]$ErrorCode = '')
    $transaction = $Connection.BeginTransaction()
    try {
        $attempt = New-DbCommand $Connection 'UPDATE [Attempt] SET [EndedAtUtc]=?,[Outcome]=?,[SanitizedError]=? WHERE [Id]=? AND [Outcome]=?' $transaction
        $null = $attempt.Parameters.Add('ended', [System.Data.OleDb.OleDbType]::Date)
        $attempt.Parameters[0].Value = [DateTime]::UtcNow
        Add-TextParameter $attempt 'outcome' 30 $Outcome
        Add-TextParameter $attempt 'error' 255 $ErrorCode
        $null = $attempt.Parameters.Add('id', [System.Data.OleDb.OleDbType]::Integer)
        $attempt.Parameters[3].Value = $AttemptId
        Add-TextParameter $attempt 'started' 30 'started'
        if ($attempt.ExecuteNonQuery() -ne 1) { throw 'Attempt was already finalized' }
        $delivery = New-DbCommand $Connection 'UPDATE [Delivery] SET [Status]=?,[LastErrorCode]=? WHERE [Id]=? AND [Status]=?' $transaction
        Add-TextParameter $delivery 'status' 30 $Status
        Add-TextParameter $delivery 'error' 100 $ErrorCode
        $null = $delivery.Parameters.Add('id', [System.Data.OleDb.OleDbType]::Integer)
        $delivery.Parameters[2].Value = $DeliveryId
        Add-TextParameter $delivery 'inflight' 30 'in_flight'
        if ($delivery.ExecuteNonQuery() -ne 1) { throw 'Delivery was already finalized' }
        $transaction.Commit()
    }
    catch { $transaction.Rollback(); throw }
}

function Pause-DispatchForReview {
    param($Connection, [int]$DeliveryId)
    $transaction = $Connection.BeginTransaction()
    try {
        $command = New-DbCommand $Connection "UPDATE [Campaign] SET [Status]='approved_paused' WHERE [Status]='running'" $transaction
        $null = $command.ExecuteNonQuery()
        $command = New-DbCommand $Connection 'UPDATE [OperationalState] SET [GlobalPause]=TRUE WHERE [Id]=1' $transaction
        $null = $command.ExecuteNonQuery()
        Write-CampaignAudit $Connection 'dispatch_uncertain' ([string]$DeliveryId) 'Provider outcome requires manual review' $transaction
        $transaction.Commit()
    }
    catch { $transaction.Rollback(); throw }
}

function Complete-FinishedCampaigns {
    param($Connection)
    $command = New-DbCommand $Connection "UPDATE [Campaign] SET [Status]='completed' WHERE [Status]='running' AND [Id] NOT IN (SELECT [CampaignId] FROM [Delivery] WHERE [Status] IN ('pending','in_flight','uncertain'))"
    $null = $command.ExecuteNonQuery()
}