param(
    [string]$BaseUrl = "http://localhost:9900",
    [string]$SessionId = "mvp-demo-payment-timeout-001",
    [string]$RequestFile = "$PSScriptRoot/../requests/payment-timeout-chat.json",
    [string]$OutputDir = "$PSScriptRoot/../output"
)

$ErrorActionPreference = "Stop"

function ConvertFrom-NamedSse {
    param([Parameter(Mandatory = $true)][string]$Content)

    $events = @()
    foreach ($frame in ($Content -split "(?:\r?\n){2,}")) {
        if ([string]::IsNullOrWhiteSpace($frame)) {
            continue
        }

        $name = $null
        $dataLines = @()
        foreach ($line in ($frame -split "\r?\n")) {
            if ($line.StartsWith("event:")) {
                $name = $line.Substring(6).Trim()
            } elseif ($line.StartsWith("data:")) {
                $dataLines += $line.Substring(5).TrimStart()
            }
        }

        if ([string]::IsNullOrWhiteSpace($name) -or $dataLines.Count -eq 0) {
            throw "Invalid named SSE frame: $frame"
        }
        $rawData = $dataLines -join "`n"
        $events += [pscustomobject]@{
            name = $name
            payload = $rawData | ConvertFrom-Json
        }
    }
    return @($events)
}

function Assert-ChatSseContract {
    param(
        [Parameter(Mandatory = $true)][array]$Events,
        [Parameter(Mandatory = $true)][string]$ExpectedSessionId
    )

    if ($Events.Count -lt 3) {
        throw "Chat SSE must contain metadata, a terminal event, and done"
    }
    if ($Events[0].name -ne "metadata") {
        throw "First Chat SSE event must be metadata"
    }
    if ($Events[-1].name -ne "done") {
        throw "Last Chat SSE event must be done"
    }

    $terminalEvents = @($Events | Where-Object { $_.name -in @("content", "failure") })
    if ($terminalEvents.Count -ne 1 -or $Events[-2].name -ne $terminalEvents[0].name) {
        throw "Chat SSE must contain exactly one content or failure immediately before done"
    }

    $allowed = @("metadata", "status", "content", "failure", "done")
    $unknown = @($Events | Where-Object { $_.name -notin $allowed })
    if ($unknown.Count -gt 0) {
        throw "Chat SSE contains unknown events: $($unknown.name -join ', ')"
    }
    $invalidMiddle = @()
    if ($Events.Count -gt 3) {
        $invalidMiddle = @($Events[1..($Events.Count - 3)] |
            Where-Object { $_.name -ne "status" })
    }
    if ($invalidMiddle.Count -gt 0) {
        throw "Only status events are allowed between metadata and the terminal event"
    }

    $metadata = $Events[0].payload
    if ($metadata.session_id -ne $ExpectedSessionId) {
        throw "SSE session_id does not match the requested SessionId"
    }
    if ([string]::IsNullOrWhiteSpace([string]$metadata.run_id)) {
        throw "SSE metadata is missing run_id"
    }

    $outcome = [string]$Events[-1].payload.outcome
    if ($terminalEvents[0].name -eq "failure" -and $outcome -ne "FAILED") {
        throw "A failure event must end with outcome FAILED"
    }
    if ($terminalEvents[0].name -eq "content" -and $outcome -notin @("SUCCESS", "FALLBACK")) {
        throw "A content event must end with outcome SUCCESS or FALLBACK"
    }
}

New-Item -ItemType Directory -Force -Path $OutputDir | Out-Null

$request = Get-Content -Raw -Encoding UTF8 -Path $RequestFile | ConvertFrom-Json
$request.Id = $SessionId
$body = $request | ConvertTo-Json -Depth 8

Write-Host "Running payment-timeout Chat E2E"
Write-Host "BaseUrl: $BaseUrl"
Write-Host "SessionId: $SessionId"

$response = Invoke-WebRequest `
    -UseBasicParsing `
    -Method Post `
    -Uri "$BaseUrl/api/chat" `
    -Headers @{ Accept = "text/event-stream" } `
    -ContentType "application/json; charset=utf-8" `
    -Body $body

$response.Content | Set-Content -Encoding UTF8 -Path "$OutputDir/chat-sse.txt"
$events = @(ConvertFrom-NamedSse -Content $response.Content)
Assert-ChatSseContract -Events $events -ExpectedSessionId $SessionId
$events | ConvertTo-Json -Depth 50 | Set-Content -Encoding UTF8 -Path "$OutputDir/chat-events.json"

$runId = [string]$events[0].payload.run_id
Write-Host "RunId: $runId"
Write-Host "SSE sequence: $($events.name -join ' -> ')"

$trace = Invoke-RestMethod `
    -Method Get `
    -Uri "$BaseUrl/api/diagnosis/$SessionId/trace?runId=$([System.Uri]::EscapeDataString($runId))"
$trace | ConvertTo-Json -Depth 50 | Set-Content -Encoding UTF8 -Path "$OutputDir/trace-response.json"

Write-Host "E2E artifacts:"
Write-Host "- $OutputDir/chat-sse.txt"
Write-Host "- $OutputDir/chat-events.json"
Write-Host "- $OutputDir/trace-response.json"