[CmdletBinding()]
param(
    [string]$StatusPath = (Join-Path $env:LOCALAPPDATA 'Domovoy\monitoring\status.json'),
    [string]$StatePath = (Join-Path $env:LOCALAPPDATA 'Domovoy\monitoring\notification-state.json'),
    [ValidateRange(1, 168)]
    [int]$ReminderHours = 6,
    [switch]$Force,
    [switch]$NoDisplay
)

$ErrorActionPreference = 'Stop'
Set-StrictMode -Version Latest

function Write-AtomicJson {
    param([Parameter(Mandatory)]$Value, [Parameter(Mandatory)][string]$Path)

    $directory = Split-Path -Parent $Path
    if (-not (Test-Path -LiteralPath $directory -PathType Container)) {
        New-Item -ItemType Directory -Path $directory -Force | Out-Null
    }
    $temporary = Join-Path $directory ('.{0}.{1}.tmp' -f (Split-Path -Leaf $Path), [guid]::NewGuid().ToString('N'))
    try {
        $Value | ConvertTo-Json -Depth 8 | Set-Content -LiteralPath $temporary -Encoding utf8NoBOM
        Move-Item -LiteralPath $temporary -Destination $Path -Force
    }
    finally {
        if (Test-Path -LiteralPath $temporary) { Remove-Item -LiteralPath $temporary -Force }
    }
}

if (-not (Test-Path -LiteralPath $StatusPath -PathType Leaf)) { throw "Health status not found: $StatusPath" }
$status = Get-Content -LiteralPath $StatusPath -Raw | ConvertFrom-Json
if ($status.version -ne 1 -or $status.overall -notin @('healthy', 'degraded')) { throw 'Unsupported health status document' }

$now = [DateTimeOffset]::UtcNow
$previous = $null
if (Test-Path -LiteralPath $StatePath -PathType Leaf) {
    $previous = Get-Content -LiteralPath $StatePath -Raw | ConvertFrom-Json
}

$kind = $null
if ($Force) {
    $kind = if ($status.overall -eq 'healthy') { 'recovered' } else { 'degraded' }
}
elseif ($status.overall -eq 'degraded') {
    if ($null -eq $previous -or $previous.last_status -ne 'degraded') {
        $kind = 'degraded'
    }
    elseif ($null -ne $previous.last_notification_at_utc) {
        $lastNotification = if ($previous.last_notification_at_utc -is [DateTime]) {
            [DateTimeOffset]$previous.last_notification_at_utc
        }
        else {
            [DateTimeOffset]::Parse([string]$previous.last_notification_at_utc, [Globalization.CultureInfo]::InvariantCulture)
        }
        if (($now - $lastNotification).TotalHours -ge $ReminderHours) { $kind = 'reminder' }
    }
}
elseif ($null -ne $previous -and $previous.last_status -eq 'degraded') {
    $kind = 'recovered'
}

$lastNotificationAt = if ($null -ne $previous -and $null -ne $previous.last_notification_at_utc) {
    ([DateTimeOffset]$previous.last_notification_at_utc).ToString('o')
}
else { $null }
$lastNotificationKind = if ($null -ne $previous) { $previous.last_notification_kind } else { $null }

if ($null -ne $kind) {
    $failedNames = @($status.checks | Where-Object { -not $_.ok } | ForEach-Object { [string]$_.name })
    switch ($kind) {
        'degraded' {
            $title = 'Домовой: требуется внимание'
            $body = if ($failedNames.Count -gt 0) { 'Сбой: ' + ($failedNames -join ', ') } else { 'Мониторинг обнаружил сбой.' }
            $icon = 'Error'
        }
        'reminder' {
            $title = 'Домовой: сбой продолжается'
            $body = if ($failedNames.Count -gt 0) { 'Не исправлено: ' + ($failedNames -join ', ') } else { 'Состояние остается ухудшенным.' }
            $icon = 'Warning'
        }
        default {
            $title = 'Домовой: работа восстановлена'
            $body = 'Все проверки снова проходят успешно.'
            $icon = 'Info'
        }
    }

    if (-not $NoDisplay) {
        Add-Type -AssemblyName System.Windows.Forms
        Add-Type -AssemblyName System.Drawing
        $notification = [System.Windows.Forms.NotifyIcon]::new()
        try {
            $notification.Icon = switch ($icon) {
                'Error' { [System.Drawing.SystemIcons]::Error }
                'Warning' { [System.Drawing.SystemIcons]::Warning }
                default { [System.Drawing.SystemIcons]::Information }
            }
            $notification.Visible = $true
            $notification.BalloonTipIcon = [System.Enum]::Parse([System.Windows.Forms.ToolTipIcon], $icon)
            $notification.BalloonTipTitle = $title
            $notification.BalloonTipText = $body
            $notification.ShowBalloonTip(8000)
            Start-Sleep -Seconds 9
        }
        finally {
            $notification.Dispose()
        }
    }

    $lastNotificationAt = $now.ToString('o')
    $lastNotificationKind = $kind
}

$state = [ordered]@{
    version = 1
    last_status = [string]$status.overall
    last_observed_at_utc = $now.ToString('o')
    last_notification_at_utc = $lastNotificationAt
    last_notification_kind = $lastNotificationKind
}
Write-AtomicJson -Value $state -Path $StatePath

$result = if ($null -eq $kind) { 'suppressed' } elseif ($NoDisplay) { 'simulated' } else { 'sent' }
Write-Output "notification=$result status=$($status.overall) kind=$kind"