[CmdletBinding()]
param(
    [string]$Version = "1.38.4",
    [string]$ExpectedSha256 = "6c7878ec319471ac85b82443baec2f3fa5dbcf1b6e2da5d5cd2cbb60fff2bb45",
    [string]$ConfigurationTemplate = "$PSScriptRoot\mission-core-windows.conf.tmpl",
    [string]$PipelineCollector = "$PSScriptRoot\Get-NdcMissionCorePipelineTelemetry.ps1",
    [string]$PipelineJournal = "D:\NDC_MISSIONCORE\runtime\derived\.perception-persistent-publish\pipeline-telemetry.jsonl"
)

$ErrorActionPreference = "Stop"
$serviceName = "telegraf"
$installRoot = "C:\Program Files\NDC\Mission Core\Telegraf"
$configurationRoot = "C:\ProgramData\NDC\MissionCore\telemetry-agent"
$configurationPath = Join-Path $configurationRoot "telegraf.conf"
$collectorPath = Join-Path $configurationRoot "Get-NdcMissionCorePipelineTelemetry.ps1"
$archiveUrl = "https://dl.influxdata.com/telegraf/releases/telegraf-$($Version)_windows_amd64.zip"
$payload = [Console]::In.ReadToEnd() | ConvertFrom-Json

foreach ($name in @(
    "MISSIONCORE_CONTOUR_ID",
    "MISSIONCORE_AGENT_ID",
    "MISSIONCORE_NODE_ID",
    "MISSIONCORE_MQTT_HOST",
    "MISSIONCORE_MQTT_PORT",
    "MISSIONCORE_MQTT_USERNAME",
    "MISSIONCORE_MQTT_PASSWORD",
    "MISSIONCORE_TELEMETRY_INTERVAL"
)) {
    $value = $payload.$name
    if (-not $value) {
        throw "Provisioning payload is missing $name"
    }
    Set-Item -Path "Env:$name" -Value ([string]$value)
}

if (Get-Service -Name $serviceName -ErrorAction SilentlyContinue) {
    throw "Service '$serviceName' already exists; refusing an implicit replacement"
}
if (-not (Test-Path -LiteralPath $ConfigurationTemplate -PathType Leaf)) {
    throw "Configuration template not found: $ConfigurationTemplate"
}
if (-not (Test-Path -LiteralPath $PipelineCollector -PathType Leaf)) {
    throw "Pipeline collector not found: $PipelineCollector"
}
$journalParent = Get-Item -LiteralPath (
    Resolve-Path -LiteralPath (Split-Path $PipelineJournal -Parent)
).Path -Force
if (
    -not $journalParent.PSIsContainer -or
    ($journalParent.Attributes -band [IO.FileAttributes]::ReparsePoint) -or
    [IO.Path]::GetPathRoot($journalParent.FullName).TrimEnd("\") -ine "D:"
) {
    throw "Pipeline journal parent must be a real D: directory"
}
if (-not (Test-Path -LiteralPath $PipelineJournal)) {
    New-Item -ItemType File -Path $PipelineJournal | Out-Null
}
$journal = Get-Item -LiteralPath $PipelineJournal -Force
if (
    $journal.PSIsContainer -or
    ($journal.Attributes -band [IO.FileAttributes]::ReparsePoint)
) {
    throw "Pipeline journal must be a regular file"
}

$temporaryRoot = Join-Path $env:TEMP "ndc-mission-core-telegraf-$([Guid]::NewGuid().ToString('N'))"
$archivePath = Join-Path $temporaryRoot "telegraf.zip"
$expandedRoot = Join-Path $temporaryRoot "expanded"
try {
    New-Item -ItemType Directory -Path $temporaryRoot, $expandedRoot -Force | Out-Null
    Invoke-WebRequest -UseBasicParsing -Uri $archiveUrl -OutFile $archivePath
    $actualSha256 = (Get-FileHash -LiteralPath $archivePath -Algorithm SHA256).Hash.ToLowerInvariant()
    if ($actualSha256 -ne $ExpectedSha256.ToLowerInvariant()) {
        throw "Telegraf archive SHA256 mismatch"
    }
    Expand-Archive -LiteralPath $archivePath -DestinationPath $expandedRoot
    $sourceExecutable = Get-ChildItem -Path $expandedRoot -Filter "telegraf.exe" -Recurse |
        Select-Object -First 1
    if (-not $sourceExecutable) {
        throw "telegraf.exe is missing from the verified archive"
    }

    New-Item -ItemType Directory -Path $installRoot, $configurationRoot -Force | Out-Null
    Copy-Item -LiteralPath $sourceExecutable.FullName -Destination (Join-Path $installRoot "telegraf.exe")
    Copy-Item -LiteralPath $ConfigurationTemplate -Destination $configurationPath
    Copy-Item -LiteralPath $PipelineCollector -Destination $collectorPath
    & icacls.exe $configurationRoot /inheritance:r /grant:r `
        "*S-1-5-18:(OI)(CI)F" "*S-1-5-32-544:(OI)(CI)F" | Out-Null
    if ($LASTEXITCODE -ne 0) {
        throw "Failed to restrict the telemetry agent configuration directory"
    }

    $executable = Join-Path $installRoot "telegraf.exe"
    $validationOutput = Join-Path $temporaryRoot "validation.out.log"
    $validationError = Join-Path $temporaryRoot "validation.error.log"
    $validation = Start-Process -FilePath $executable `
        -ArgumentList @("--config", $configurationPath, "--test") `
        -NoNewWindow -Wait -PassThru `
        -RedirectStandardOutput $validationOutput `
        -RedirectStandardError $validationError
    if ($validation.ExitCode -ne 0) {
        $validationDetail = Get-Content -LiteralPath $validationError -Tail 8 |
            Out-String
        throw "Telegraf configuration validation failed: $validationDetail"
    }

    & $executable --service install --config $configurationPath
    if ($LASTEXITCODE -ne 0) {
        throw "Telegraf service installation failed"
    }
    $serviceEnvironment = @(
        "MISSIONCORE_CONTOUR_ID=$($payload.MISSIONCORE_CONTOUR_ID)",
        "MISSIONCORE_AGENT_ID=$($payload.MISSIONCORE_AGENT_ID)",
        "MISSIONCORE_NODE_ID=$($payload.MISSIONCORE_NODE_ID)",
        "MISSIONCORE_MQTT_HOST=$($payload.MISSIONCORE_MQTT_HOST)",
        "MISSIONCORE_MQTT_PORT=$($payload.MISSIONCORE_MQTT_PORT)",
        "MISSIONCORE_MQTT_USERNAME=$($payload.MISSIONCORE_MQTT_USERNAME)",
        "MISSIONCORE_MQTT_PASSWORD=$($payload.MISSIONCORE_MQTT_PASSWORD)",
        "MISSIONCORE_TELEMETRY_INTERVAL=$($payload.MISSIONCORE_TELEMETRY_INTERVAL)"
    )
    $serviceRegistryPath = "HKLM:\SYSTEM\CurrentControlSet\Services\$serviceName"
    Set-ItemProperty -Path $serviceRegistryPath -Name Environment `
        -Type MultiString -Value $serviceEnvironment
    Set-ItemProperty -Path $serviceRegistryPath -Name DisplayName `
        -Value "NDC Mission Core Telemetry Agent"
    & sc.exe config $serviceName DisplayName= "NDC Mission Core Telemetry Agent" | Out-Null
    if ($LASTEXITCODE -ne 0) {
        throw "Failed to apply the NDC service display name"
    }
    Set-Service -Name $serviceName -StartupType Automatic
    Start-Service -Name $serviceName
    $service = Get-Service -Name $serviceName
    $service.WaitForStatus([ServiceProcess.ServiceControllerStatus]::Running, [TimeSpan]::FromSeconds(20))

    [ordered]@{
        SchemaVersion = "missioncore.telemetry-agent-install-result/v1"
        Agent = "Telegraf"
        Version = $Version
        ServiceName = $service.Name
        DisplayName = $service.DisplayName
        Status = $service.Status.ToString()
        StartType = $service.StartType.ToString()
        Configuration = $configurationPath
        PipelineCollector = $collectorPath
        PipelineJournal = $PipelineJournal
        Sha256 = $actualSha256
    } | ConvertTo-Json -Compress
}
finally {
    Remove-Item -LiteralPath $temporaryRoot -Recurse -Force -ErrorAction SilentlyContinue
}