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

function Read-CampaignRequest {
    param([string]$Path)
    if (-not (Test-Path -LiteralPath $Path -PathType Leaf)) { throw 'Campaign request file not found' }
    if ((Get-Item -LiteralPath $Path).Length -gt 16384) { throw 'Campaign request is too large' }
    $request = Get-Content -LiteralPath $Path -Raw -Encoding UTF8 | ConvertFrom-Json
    $name = ([string]$request.Name).Trim()
    $subject = ([string]$request.Subject).Trim()
    $id = 0
    if (-not [int]::TryParse([string]$request.TemplateId, [ref]$id) -or $id -lt 1) {
        throw 'Select a template version'
    }
    if ($name.Length -lt 1 -or $name.Length -gt 200 -or $name -match '[\x00-\x1f]') {
        throw 'Campaign name must be 1-200 characters without control characters'
    }
    if ($subject.Length -lt 1 -or $subject.Length -gt 240 -or $subject -match '[\x00-\x1f]') {
        throw 'Subject must be 1-240 characters without control characters'
    }
    # Absent ContactIds means every eligible contact; a present list limits the campaign to those ids.
    $contactIds = $null
    if ($null -ne $request.ContactIds) {
        $seen = @{}
        foreach ($value in @($request.ContactIds)) {
            $contactId = 0
            if (-not [int]::TryParse([string]$value, [ref]$contactId) -or $contactId -lt 1) {
                throw 'Invalid contact selection'
            }
            $seen[$contactId] = $true
        }
        if ($seen.Count -lt 1) { throw 'Select at least one recipient' }
        $contactIds = @($seen.Keys | Sort-Object)
    }
    return @{ Name = $name; Subject = $subject; TemplateId = $id; ContactIds = $contactIds;
        ReviewToken = ([string]$request.ReviewToken).Trim(); TestReceived = ($request.TestReceived -eq $true) }
}

function Get-CampaignIdentity {
    param($Context)
    $settings = $Context.Settings
    foreach ($key in @('SMTP_FROM','SMTP_REPLY_TO','SMTP_TEST_TO','BUSINESS_POSTAL_ADDRESS')) {
        if (-not $settings[$key] -or -not $settings[$key].Trim()) { throw "Set $key in config.ini first" }
    }
    $from = $settings['SMTP_FROM'].Trim()
    $replyTo = $settings['SMTP_REPLY_TO'].Trim()
    $testTo = $settings['SMTP_TEST_TO'].Trim()
    foreach ($address in @($from, $replyTo, $testTo)) {
        $parsed = New-Object System.Net.Mail.MailAddress($address)
        if ($parsed.Address -ne $address) { throw 'SMTP addresses must each be a single bare email address' }
    }
    $postal = $settings['BUSINESS_POSTAL_ADDRESS'].Trim()
    if ($postal.Length -gt 500 -or $postal -match '[\x00-\x1f]') {
        throw 'BUSINESS_POSTAL_ADDRESS must be one line of at most 500 characters'
    }
    return @{ From = $from; ReplyTo = $replyTo; TestTo = $testTo; Postal = $postal }
}

function New-DbCommand {
    param($Connection, [string]$Sql, $Transaction = $null)
    $command = $Connection.CreateCommand()
    $command.CommandText = $Sql
    if ($Transaction) { $command.Transaction = $Transaction }
    return $command
}

function Get-EligibleContacts {
    param($Connection, $Transaction = $null, $ContactIds = $null)
    $command = New-DbCommand $Connection "SELECT c.[Id],c.[EmailOriginal],c.[EmailKey] FROM [Contact] AS c LEFT JOIN [Suppression] AS s ON c.[EmailKey]=s.[EmailKey] WHERE s.[EmailKey] IS NULL AND c.[Country]='US' AND c.[EligibilityBasis]='public_listing' ORDER BY c.[Id]" $Transaction
    $reader = $command.ExecuteReader()
    $contacts = New-Object System.Collections.ArrayList
    try {
        while ($reader.Read()) {
            $null = $contacts.Add(@{ Id = [int]$reader.GetValue(0);
                Email = [string]$reader.GetValue(1); Key = [string]$reader.GetValue(2) })
        }
    }
    finally { $reader.Dispose() }
    if ($null -ne $ContactIds) {
        $eligible = @{}
        foreach ($contact in $contacts) { $eligible[$contact.Id] = $contact }
        $selected = New-Object System.Collections.ArrayList
        foreach ($contactId in $ContactIds) {
            if (-not $eligible.ContainsKey([int]$contactId)) {
                throw 'A selected contact is no longer eligible or was suppressed. Review again.'
            }
            $null = $selected.Add($eligible[[int]$contactId])
        }
        $contacts = $selected
    }
    if ($contacts.Count -lt 1) { throw 'No eligible, unsuppressed US contacts are available' }
    if ($contacts.Count -gt 500) { throw 'This version supports at most 500 eligible contacts per campaign' }
    return ,$contacts
}

function Get-TemplateSnapshot {
    param($Connection, [int]$TemplateId, $Transaction = $null)
    $command = New-DbCommand $Connection 'SELECT [TemplateName],[VersionNumber],[HtmlContent],[ContentHash],[ValidationStatus] FROM [TemplateVersion] WHERE [Id]=?' $Transaction
    $null = $command.Parameters.Add('id', [System.Data.OleDb.OleDbType]::Integer)
    $command.Parameters[0].Value = $TemplateId
    $reader = $command.ExecuteReader()
    try {
        if (-not $reader.Read()) { throw 'Selected template version was not found' }
        $name = [string]$reader.GetValue(0)
        $version = [int]$reader.GetValue(1)
        $html = [string]$reader.GetValue(2)
        $hash = [string]$reader.GetValue(3)
        if ([string]$reader.GetValue(4) -ne 'validated' -or
            (Get-HashHex ([System.Text.Encoding]::UTF8.GetBytes($html))) -ne $hash) {
            throw 'Template validation or content hash failed'
        }
    }
    finally { $reader.Dispose() }
    $document = Read-SafeTemplateXml $html $true
    $images = New-Object System.Collections.ArrayList
    $command = New-DbCommand $Connection 'SELECT [ContentType],[ContentHash],[SnapshotBytes],[ContentId] FROM [TemplateImage] WHERE [TemplateVersionId]=? ORDER BY [Id]' $Transaction
    $null = $command.Parameters.Add('id', [System.Data.OleDb.OleDbType]::Integer)
    $command.Parameters[0].Value = $TemplateId
    $reader = $command.ExecuteReader()
    try {
        while ($reader.Read()) {
            $bytes = [byte[]]$reader.GetValue(2)
            $cid = [string]$reader.GetValue(3)
            $type = [string]$reader.GetValue(0)
            if ((Get-HashHex $bytes) -ne [string]$reader.GetValue(1) -or
                $cid -notmatch '^mm-[0-9a-f]{32}@local$' -or
                $type -notin @('image/png','image/jpeg','image/gif')) {
                throw 'Stored template image failed validation'
            }
            $null = $images.Add(@{ Bytes = $bytes; Cid = $cid; Type = $type })
        }
    }
    finally { $reader.Dispose() }
    $references = @{}
    foreach ($image in $images) { $references['cid:' + $image.Cid] = $false }
    foreach ($node in $document.GetElementsByTagName('img')) {
        $src = $node.GetAttribute('src')
        if (-not $references.ContainsKey($src)) { throw 'Template image reference has no stored snapshot' }
        $references[$src] = $true
    }
    foreach ($entry in $references.GetEnumerator()) {
        if (-not $entry.Value) { throw 'Stored template image has no HTML reference' }
    }
    return @{ Name = $name; Version = $version; Html = $html; Hash = $hash;
        Document = $document; Images = $images }
}

function Add-CampaignFooter {
    param($Document, $Identity)
    $body = @($Document.DocumentElement.ChildNodes | Where-Object { $_.LocalName -eq 'body' })[0]
    if (-not $body) { throw 'Stored template is missing <body>' }
    $ns = $Document.DocumentElement.NamespaceURI
    $divider = $Document.CreateElement('hr', $ns)
    $null = $body.AppendChild($divider)
    $footer = $Document.CreateElement('div', $ns)
    $footer.SetAttribute('style', 'font-size:12px; color:#444444')
    foreach ($line in @(
        'Advertisement from ' + $Identity.From + '.',
        $Identity.Postal,
        'To stop receiving marketing emails, reply to ' + $Identity.ReplyTo + ' with UNSUBSCRIBE in the subject.'
    )) {
        $paragraph = $Document.CreateElement('p', $ns)
        $null = $paragraph.AppendChild($Document.CreateTextNode($line))
        $null = $footer.AppendChild($paragraph)
    }
    $null = $body.AppendChild($footer)
    return $Document.OuterXml
}

function Get-CampaignReview {
    param($Context, $Request, $Connection, $Transaction = $null)
    $identity = Get-CampaignIdentity $Context
    $template = Get-TemplateSnapshot $Connection $Request.TemplateId $Transaction
    $contacts = Get-EligibleContacts $Connection $Transaction $Request.ContactIds
    $html = Add-CampaignFooter $template.Document $identity
    $parts = New-Object System.Collections.ArrayList
    foreach ($value in @($Request.Name, $Request.Subject, [string]$Request.TemplateId,
        $template.Hash, $identity.From, $identity.ReplyTo, $identity.Postal)) {
        $null = $parts.Add($value)
    }
    foreach ($contact in $contacts) { $null = $parts.Add(([string]$contact.Id + ':' + $contact.Key)) }
    $token = Get-HashHex ([System.Text.Encoding]::UTF8.GetBytes(($parts -join [char]0)))
    return @{ Name = $Request.Name; Subject = $Request.Subject; TemplateId = $Request.TemplateId;
        TemplateName = $template.Name; TemplateVersion = $template.Version; Identity = $identity;
        Contacts = $contacts; Html = $html; Images = $template.Images; Token = $token }
}

function Assert-ReviewToken {
    param($Request, $Review)
    if ($Request.ReviewToken -notmatch '^[0-9a-f]{64}$' -or $Request.ReviewToken -ne $Review.Token) {
        throw 'Campaign inputs, recipients, template, or settings changed. Review again.'
    }
}

function Write-CampaignPreview {
    param($Review, [string]$OutputRoot)
    $folder = Join-Path $OutputRoot ([guid]::NewGuid().ToString('N'))
    $null = New-Item -ItemType Directory -Path $folder -Force
    $document = Read-SafeTemplateXml $Review.Html $true
    $index = 0
    foreach ($image in $Review.Images) {
        $index++
        $extension = switch ($image.Type) { 'image/png' { 'png' } 'image/jpeg' { 'jpg' } 'image/gif' { 'gif' } }
        $filename = "image-$index.$extension"
        [System.IO.File]::WriteAllBytes((Join-Path $folder $filename), $image.Bytes)
        foreach ($node in $document.GetElementsByTagName('img')) {
            if ($node.GetAttribute('src') -eq ('cid:' + $image.Cid)) { $node.SetAttribute('src', $filename) }
        }
    }
    $file = Join-Path $folder 'preview.html'
    [System.IO.File]::WriteAllText($file, $document.OuterXml, (New-Object System.Text.UTF8Encoding($false)))
    return $file
}

function Write-CampaignAudit {
    param($Connection, [string]$Action, [string]$Token, [string]$Detail, $Transaction = $null)
    $command = New-DbCommand $Connection 'INSERT INTO [AuditEvent] ([Actor],[Action],[EntityId],[TimestampUtc],[Detail]) VALUES (?,?,?,?,?)' $Transaction
    Add-TextParameter $command 'actor' 100 'local_operator'
    Add-TextParameter $command 'action' 100 $Action
    Add-TextParameter $command 'entity' 100 $Token
    $null = $command.Parameters.Add('at', [System.Data.OleDb.OleDbType]::Date)
    $command.Parameters[3].Value = [DateTime]::UtcNow
    Add-TextParameter $command 'detail' 255 $Detail
    $null = $command.ExecuteNonQuery()
}