[CmdletBinding()]
param(
    [Alias("h")]
    [switch]$Help,
    [string]$ApiHost = "127.0.0.1",
    [int]$Port = 3101,
    [string]$Log = "warn,tower_http=warn",
    [int]$StartupTimeoutSeconds = 30
)

$ErrorActionPreference = "Stop"

function Write-Usage {
    @(
        'Usage:'
        '  ./server-rs/scripts/smoke.ps1'
        '  ./server-rs/scripts/smoke.ps1 -ApiHost 127.0.0.1 -Port 3201 -Log "info,tower_http=info"'
        ''
        'Notes:'
        '  1. Build api-server and start an ephemeral local process'
        '  2. Verify /healthz raw payload, response headers, and envelope contract'
        '  3. Stop the temporary process automatically after the smoke checks finish'
    ) -join [Environment]::NewLine
}

function Assert-Condition {
    param(
        [bool]$Condition,
        [string]$Message
    )

    if (-not $Condition) {
        throw $Message
    }
}

function Set-InheritedEnvVar {
    param(
        [string]$Name,
        [string]$Value,
        [hashtable]$Snapshot
    )

    if (-not $Snapshot.ContainsKey($Name)) {
        $Snapshot[$Name] = [Environment]::GetEnvironmentVariable($Name, "Process")
    }

    [Environment]::SetEnvironmentVariable($Name, $Value, "Process")
}

function Restore-InheritedEnvVars {
    param([hashtable]$Snapshot)

    foreach ($entry in $Snapshot.GetEnumerator()) {
        [Environment]::SetEnvironmentVariable($entry.Key, $entry.Value, "Process")
    }
}

function Get-HeaderValue {
    param(
        $Headers,
        [string]$Name
    )

    if ($null -eq $Headers) {
        return $null
    }

    return $Headers[$Name]
}

function Wait-ForHealthz {
    param(
        [string]$Uri,
        [int]$TimeoutSeconds,
        $Process
    )

    $deadline = (Get-Date).AddSeconds($TimeoutSeconds)
    $lastError = $null

    while ((Get-Date) -lt $deadline) {
        if ($Process.HasExited) {
            throw "api-server exited before /healthz became ready."
        }

        try {
            $response = Invoke-WebRequest -Uri $Uri -UseBasicParsing -TimeoutSec 2
            if ($response.StatusCode -eq 200) {
                return
            }

            $lastError = "Unexpected status code $($response.StatusCode)"
        }
        catch {
            $lastError = $_.Exception.Message
        }

        Start-Sleep -Milliseconds 300
    }

    throw "Timed out waiting for /healthz readiness. Last error: $lastError"
}

function Write-ProcessLogs {
    param(
        [string]$StdoutLog,
        [string]$StderrLog
    )

    if (Test-Path $StdoutLog) {
        Write-Host "[server-rs:smoke] stdout:"
        Get-Content -Path $StdoutLog
    }

    if (Test-Path $StderrLog) {
        Write-Host "[server-rs:smoke] stderr:"
        Get-Content -Path $StderrLog
    }
}

if ($Help) {
    Write-Usage
    exit 0
}

$scriptDir = Split-Path -Parent $MyInvocation.MyCommand.Path
$serverRsDir = Split-Path -Parent $scriptDir
$manifestPath = Join-Path $serverRsDir "Cargo.toml"
$binaryPath = Join-Path $serverRsDir "target\debug\api-server.exe"
$baseUrl = "http://$ApiHost`:$Port"
$healthzUrl = "$baseUrl/healthz"
$runId = [Guid]::NewGuid().ToString("N")
$stdoutLog = Join-Path $env:TEMP "genarrative-server-rs-smoke-$runId.stdout.log"
$stderrLog = Join-Path $env:TEMP "genarrative-server-rs-smoke-$runId.stderr.log"
$envSnapshot = @{}
$serverProcess = $null
$shouldKeepLogs = $false

if (-not (Test-Path $manifestPath)) {
    throw "Missing server-rs/Cargo.toml, cannot start smoke script."
}

Push-Location $serverRsDir
try {
    Write-Host "[server-rs:smoke] step: cargo build -p api-server"
    cargo build -p api-server --manifest-path $manifestPath

    Assert-Condition (Test-Path $binaryPath) "Missing api-server binary at $binaryPath after cargo build."

    Set-InheritedEnvVar -Name "GENARRATIVE_API_HOST" -Value $ApiHost -Snapshot $envSnapshot
    Set-InheritedEnvVar -Name "GENARRATIVE_API_PORT" -Value "$Port" -Snapshot $envSnapshot
    Set-InheritedEnvVar -Name "GENARRATIVE_API_LOG" -Value $Log -Snapshot $envSnapshot

    Write-Host "[server-rs:smoke] step: start api-server binary"
    $serverProcess = Start-Process `
        -FilePath $binaryPath `
        -WorkingDirectory $serverRsDir `
        -PassThru `
        -RedirectStandardOutput $stdoutLog `
        -RedirectStandardError $stderrLog

    Restore-InheritedEnvVars -Snapshot $envSnapshot

    Write-Host "[server-rs:smoke] step: wait for /healthz readiness"
    Wait-ForHealthz -Uri $healthzUrl -TimeoutSeconds $StartupTimeoutSeconds -Process $serverProcess

    $rawRequestId = "smoke-healthz-raw"
    Write-Host "[server-rs:smoke] step: verify raw /healthz contract"
    $rawResponse = Invoke-WebRequest `
        -Uri $healthzUrl `
        -Headers @{ "x-request-id" = $rawRequestId } `
        -UseBasicParsing `
        -TimeoutSec 5
    $rawBody = $rawResponse.Content | ConvertFrom-Json

    Assert-Condition ($rawResponse.StatusCode -eq 200) "Raw /healthz did not return HTTP 200."
    Assert-Condition ($rawBody.ok -eq $true) "Raw /healthz body is missing ok=true."
    Assert-Condition ($rawBody.service -eq "genarrative-node-server") "Raw /healthz body returned an unexpected service name."

    $apiVersionHeader = Get-HeaderValue -Headers $rawResponse.Headers -Name "x-api-version"
    $routeVersionHeader = Get-HeaderValue -Headers $rawResponse.Headers -Name "x-route-version"
    $requestIdHeader = Get-HeaderValue -Headers $rawResponse.Headers -Name "x-request-id"
    $responseTimeHeader = Get-HeaderValue -Headers $rawResponse.Headers -Name "x-response-time-ms"
    $responseTimeValue = 0

    Assert-Condition ($requestIdHeader -eq $rawRequestId) "Raw /healthz did not echo x-request-id."
    Assert-Condition (-not [string]::IsNullOrWhiteSpace($apiVersionHeader)) "Raw /healthz is missing x-api-version."
    Assert-Condition ($routeVersionHeader -eq $apiVersionHeader) "Raw /healthz x-route-version is not aligned with x-api-version."
    Assert-Condition (
        [int]::TryParse(($responseTimeHeader | ForEach-Object { $_ }), [ref]$responseTimeValue)
    ) "Raw /healthz x-response-time-ms is not a valid integer."
    Assert-Condition ($responseTimeValue -ge 0) "Raw /healthz x-response-time-ms must be >= 0."

    $envelopeRequestId = "smoke-healthz-envelope"
    Write-Host "[server-rs:smoke] step: verify envelope /healthz contract"
    $envelopeResponse = Invoke-WebRequest `
        -Uri $healthzUrl `
        -Headers @{
            "x-request-id" = $envelopeRequestId
            "x-genarrative-response-envelope" = "1"
        } `
        -UseBasicParsing `
        -TimeoutSec 5
    $envelopeBody = $envelopeResponse.Content | ConvertFrom-Json

    Assert-Condition ($envelopeResponse.StatusCode -eq 200) "Envelope /healthz did not return HTTP 200."
    Assert-Condition ($envelopeBody.ok -eq $true) "Envelope /healthz body is missing ok=true."
    Assert-Condition ($null -eq $envelopeBody.error) "Envelope /healthz should return error=null."
    Assert-Condition ($envelopeBody.data.ok -eq $true) "Envelope /healthz data.ok should be true."
    Assert-Condition ($envelopeBody.data.service -eq "genarrative-node-server") "Envelope /healthz returned an unexpected service name."
    Assert-Condition ($envelopeBody.meta.apiVersion -eq $apiVersionHeader) "Envelope /healthz meta.apiVersion does not match x-api-version."
    Assert-Condition ($envelopeBody.meta.requestId -eq $envelopeRequestId) "Envelope /healthz meta.requestId did not echo x-request-id."
    Assert-Condition ($envelopeBody.meta.routeVersion -eq $routeVersionHeader) "Envelope /healthz meta.routeVersion does not match x-route-version."
    Assert-Condition ($envelopeBody.meta.operation -eq "GET /healthz") "Envelope /healthz meta.operation is unexpected."
    Assert-Condition ($envelopeBody.meta.latencyMs -ge 0) "Envelope /healthz meta.latencyMs must be >= 0."

    Write-Host "[server-rs:smoke] all checks passed"
}
catch {
    $shouldKeepLogs = $true
    Write-ProcessLogs -StdoutLog $stdoutLog -StderrLog $stderrLog
    throw
}
finally {
    Restore-InheritedEnvVars -Snapshot $envSnapshot

    if ($null -ne $serverProcess -and -not $serverProcess.HasExited) {
        Stop-Process -Id $serverProcess.Id -Force
        $serverProcess.WaitForExit()
    }

    Pop-Location

    if (-not $shouldKeepLogs) {
        Remove-Item -LiteralPath $stdoutLog -ErrorAction SilentlyContinue
        Remove-Item -LiteralPath $stderrLog -ErrorAction SilentlyContinue
    }
}