param(
  [string]$ArtifactRoot = "",
  [switch]$SkipFrontendBuild,
  [switch]$SkipFrontendLint,
  [switch]$SkipBackendTests,
  [switch]$SkipDiffCheck
)

$ErrorActionPreference = "Stop"

$repoRoot = Resolve-Path (Join-Path $PSScriptRoot "..")
$timestamp = Get-Date -Format "yyyy-MM-ddTHH-mm-ss"
if ([string]::IsNullOrWhiteSpace($ArtifactRoot)) {
  $ArtifactRoot = Join-Path $repoRoot "project-docs\qa-artifacts\deployment-preflight"
}
if (-not [System.IO.Path]::IsPathRooted($ArtifactRoot)) {
  $ArtifactRoot = Join-Path $repoRoot $ArtifactRoot
}

$artifactDir = Join-Path $ArtifactRoot $timestamp
$summaryJson = Join-Path $artifactDir "deployment-preflight-summary.json"
$summaryMd = Join-Path $artifactDir "deployment-preflight-summary.md"
New-Item -ItemType Directory -Force -Path $artifactDir | Out-Null

$checks = New-Object System.Collections.Generic.List[object]

function Add-Check {
  param(
    [string]$Key,
    [string]$Label,
    [ValidateSet("pass", "fail", "skip")]
    [string]$Status,
    [string]$Detail,
    [bool]$Required = $true,
    [hashtable]$Meta = @{}
  )

  $checks.Add([ordered]@{
    key = $Key
    label = $Label
    status = $Status
    required = $Required
    detail = $Detail
    meta = $Meta
  }) | Out-Null
}

function Save-Json {
  param(
    [string]$Path,
    [object]$Value
  )
  $Value | ConvertTo-Json -Depth 12 | Set-Content -Encoding UTF8 -Path $Path
}

function Invoke-PreflightStep {
  param(
    [string]$Key,
    [string]$Label,
    [string]$Command,
    [string[]]$Arguments,
    [string]$WorkingDirectory
  )

  $logPath = Join-Path $artifactDir "$Key.log"
  $previousErrorActionPreference = $ErrorActionPreference
  $ErrorActionPreference = "Continue"
  try {
    Push-Location -LiteralPath $WorkingDirectory
    try {
      $output = & $Command @Arguments 2>&1
      $exitCode = $LASTEXITCODE
    } finally {
      Pop-Location
    }
  } finally {
    $ErrorActionPreference = $previousErrorActionPreference
  }

  $outputText = ($output -join [Environment]::NewLine)
  $outputText | Set-Content -Encoding UTF8 -Path $logPath

  if ($exitCode -eq 0) {
    Add-Check -Key $Key -Label $Label -Status "pass" -Detail "$Label passed" -Meta @{ log = $logPath }
  } else {
    Add-Check -Key $Key -Label $Label -Status "fail" -Detail "$Label failed with exit code $exitCode" -Meta @{
      exit_code = $exitCode
      log = $logPath
      working_directory = $WorkingDirectory
    }
  }
}

$branch = (git -C $repoRoot rev-parse --abbrev-ref HEAD).Trim()
$commit = (git -C $repoRoot rev-parse HEAD).Trim()

if ($SkipBackendTests) {
  Add-Check -Key "backend_tests" -Label "backend deployment tests" -Status "skip" -Required $false -Detail "Skipped by -SkipBackendTests"
} else {
  Invoke-PreflightStep `
    -Key "backend_tests" `
    -Label "backend deployment tests" `
    -Command "python" `
    -Arguments @("-m", "pytest", "backend/tests/test_system_api.py", "backend/tests/test_contracts_api.py", "backend/tests/test_search_service.py", "backend/tests/test_search_api.py") `
    -WorkingDirectory $repoRoot
}

if ($SkipFrontendLint) {
  Add-Check -Key "frontend_lint" -Label "frontend lint" -Status "skip" -Required $false -Detail "Skipped by -SkipFrontendLint"
} else {
  Invoke-PreflightStep `
    -Key "frontend_lint" `
    -Label "frontend lint" `
    -Command "npm" `
    -Arguments @("--prefix", "frontend", "run", "lint") `
    -WorkingDirectory $repoRoot
}

if ($SkipFrontendBuild) {
  Add-Check -Key "frontend_build" -Label "frontend production build" -Status "skip" -Required $false -Detail "Skipped by -SkipFrontendBuild"
} else {
  Invoke-PreflightStep `
    -Key "frontend_build" `
    -Label "frontend production build" `
    -Command "npm" `
    -Arguments @("--prefix", "frontend", "run", "build") `
    -WorkingDirectory $repoRoot
}

if ($SkipDiffCheck) {
  Add-Check -Key "diff_check" -Label "git diff whitespace check" -Status "skip" -Required $false -Detail "Skipped by -SkipDiffCheck"
} else {
  Invoke-PreflightStep `
    -Key "diff_check" `
    -Label "git diff whitespace check" `
    -Command "git" `
    -Arguments @("-C", $repoRoot, "diff", "--check") `
    -WorkingDirectory $repoRoot
}

$failedRequired = @($checks | Where-Object { $_.required -and $_.status -eq "fail" })
$skippedList = @($checks | Where-Object { $_.status -eq "skip" })
$overallStatus = if ($failedRequired.Count -gt 0) { "FAIL" } else { "PASS" }

$summary = [ordered]@{
  name = "deployment-preflight"
  status = $overallStatus
  generated_at = (Get-Date).ToUniversalTime().ToString("o")
  artifact_dir = $artifactDir
  branch = $branch
  commit = $commit
  checks = $checks
  totals = [ordered]@{
    total = $checks.Count
    failed_required = $failedRequired.Count
    skipped = $skippedList.Count
  }
}
Save-Json -Path $summaryJson -Value $summary

$markdown = New-Object System.Collections.Generic.List[string]
$markdown.Add("# Deployment Preflight") | Out-Null
$markdown.Add("") | Out-Null
$markdown.Add("- Status: $overallStatus") | Out-Null
$markdown.Add("- Generated at: $($summary.generated_at)") | Out-Null
$markdown.Add("- Branch: $branch") | Out-Null
$markdown.Add("- Commit: $commit") | Out-Null
$markdown.Add("- Artifact dir: $artifactDir") | Out-Null
$markdown.Add("") | Out-Null
$markdown.Add("| Check | Required | Status | Detail |") | Out-Null
$markdown.Add("|---|---:|---|---|") | Out-Null
foreach ($check in $checks) {
  $markdown.Add("| $($check.label) | $($check.required) | $($check.status.ToUpperInvariant()) | $($check.detail) |") | Out-Null
}
$markdown.Add("") | Out-Null
$markdown.Add("Logs:") | Out-Null
$markdown.Add("") | Out-Null
foreach ($check in $checks) {
  if ($check.meta.log) {
    $markdown.Add(('- {0}: `{1}`' -f $check.label, $check.meta.log)) | Out-Null
  }
}
$markdown | Set-Content -Encoding UTF8 -Path $summaryMd

Write-Host "DEPLOYMENT_PREFLIGHT_$overallStatus $artifactDir"
if ($overallStatus -eq "FAIL") {
  throw "Deployment preflight failed. See $summaryMd"
}