param(
  [string]$SourceDb = '',
  [int]$ConfigPort = 18085,
  [int]$EnvPort = 18086,
  [string]$EvidenceDate = (Get-Date -Format 'yyyy-MM-dd')
)

$ErrorActionPreference = 'Stop'

$projectRoot = (Resolve-Path (Join-Path $PSScriptRoot '..\..')).Path
if ([string]::IsNullOrWhiteSpace($SourceDb)) {
  $SourceDb = Join-Path $projectRoot 'data\user_management.db'
}

$evidenceRoot = Join-Path $projectRoot "docs\evidence\ops\$EvidenceDate\config-isolation"
$goCacheRoot = Join-Path $projectRoot '.cache'
$goBuildCache = Join-Path $goCacheRoot 'go-build'
$goModCache = Join-Path $goCacheRoot 'gomod'
$goPath = Join-Path $goCacheRoot 'gopath'
$timestamp = Get-Date -Format 'yyyyMMdd-HHmmss'
$drillRoot = Join-Path $evidenceRoot $timestamp
$isolatedDb = Join-Path $drillRoot 'user_management.isolated.db'
$isolatedConfig = Join-Path $drillRoot 'config.isolated.yaml'
$serverExe = Join-Path $drillRoot 'server-config-isolation.exe'
$configOnlyStdOut = Join-Path $drillRoot 'config-only.stdout.log'
$configOnlyStdErr = Join-Path $drillRoot 'config-only.stderr.log'
$envOverrideStdOut = Join-Path $drillRoot 'env-override.stdout.log'
$envOverrideStdErr = Join-Path $drillRoot 'env-override.stderr.log'
$capabilitiesConfigOnlyPath = Join-Path $drillRoot 'capabilities.config-only.json'
$capabilitiesEnvOverridePath = Join-Path $drillRoot 'capabilities.env-override.json'
$reportPath = Join-Path $drillRoot 'CONFIG_ENV_ISOLATION_DRILL.md'

New-Item -ItemType Directory -Force $evidenceRoot, $drillRoot, $goBuildCache, $goModCache, $goPath | Out-Null

function Test-UrlReady {
  param(
    [Parameter(Mandatory = $true)][string]$Url
  )

  try {
    $response = Invoke-WebRequest $Url -UseBasicParsing -TimeoutSec 2
    return $response.StatusCode -ge 200 -and $response.StatusCode -lt 500
  } catch {
    return $false
  }
}

function Wait-UrlReady {
  param(
    [Parameter(Mandatory = $true)][string]$Url,
    [Parameter(Mandatory = $true)][string]$Label,
    [int]$RetryCount = 120,
    [int]$DelayMs = 500
  )

  for ($i = 0; $i -lt $RetryCount; $i++) {
    if (Test-UrlReady -Url $Url) {
      return
    }
    Start-Sleep -Milliseconds $DelayMs
  }

  throw "$Label did not become ready: $Url"
}

function Stop-TreeProcess {
  param(
    [Parameter(Mandatory = $false)]$Process
  )

  if (-not $Process) {
    return
  }

  if (-not $Process.HasExited) {
    try {
      taskkill /PID $Process.Id /T /F *> $null
    } catch {
      Stop-Process -Id $Process.Id -Force -ErrorAction SilentlyContinue
    }
  }
}

function Build-IsolatedConfig {
  param(
    [Parameter(Mandatory = $true)][string]$TemplatePath,
    [Parameter(Mandatory = $true)][string]$OutputPath,
    [Parameter(Mandatory = $true)][string]$DbPath,
    [Parameter(Mandatory = $true)][int]$Port
  )

  $content = Get-Content $TemplatePath -Raw
  $dbPathForYaml = ($DbPath -replace '\\', '/')
  $content = $content -replace '(?m)^  port: \d+$', "  port: $Port"
  $content = [regex]::Replace(
    $content,
    '(?ms)(sqlite:\s*\r?\n\s*path:\s*).+?(\r?\n)',
    "`$1`"$dbPathForYaml`"`$2"
  )
  Set-Content -Path $OutputPath -Value $content -Encoding UTF8
}

if (-not (Test-Path $SourceDb)) {
  throw "source db not found: $SourceDb"
}

Copy-Item $SourceDb $isolatedDb -Force
Build-IsolatedConfig `
  -TemplatePath (Join-Path $projectRoot 'configs\config.yaml') `
  -OutputPath $isolatedConfig `
  -DbPath $isolatedDb `
  -Port $ConfigPort

Push-Location $projectRoot
try {
  $env:GOCACHE = $goBuildCache
  $env:GOMODCACHE = $goModCache
  $env:GOPATH = $goPath
  & go build -o $serverExe .\cmd\server
  if ($LASTEXITCODE -ne 0) {
    throw 'build config isolation server failed'
  }
} finally {
  Pop-Location
  Remove-Item Env:GOCACHE, Env:GOMODCACHE, Env:GOPATH -ErrorAction SilentlyContinue
}

$previousConfigPath = $env:UMS_CONFIG_PATH
$previousServerPort = $env:UMS_SERVER_PORT
$previousAllowedOrigins = $env:UMS_CORS_ALLOWED_ORIGINS

$configOnlyProcess = $null
$envOverrideProcess = $null

try {
  $env:UMS_CONFIG_PATH = $isolatedConfig
  Remove-Item Env:UMS_SERVER_PORT -ErrorAction SilentlyContinue
  Remove-Item Env:UMS_CORS_ALLOWED_ORIGINS -ErrorAction SilentlyContinue

  Remove-Item $configOnlyStdOut, $configOnlyStdErr -Force -ErrorAction SilentlyContinue
  $configOnlyProcess = Start-Process `
    -FilePath $serverExe `
    -WorkingDirectory $projectRoot `
    -PassThru `
    -WindowStyle Hidden `
    -RedirectStandardOutput $configOnlyStdOut `
    -RedirectStandardError $configOnlyStdErr

  Wait-UrlReady -Url "http://127.0.0.1:$ConfigPort/health" -Label 'config-only health endpoint'
  Wait-UrlReady -Url "http://127.0.0.1:$ConfigPort/health/ready" -Label 'config-only readiness endpoint'
  $configOnlyCapabilities = Invoke-RestMethod "http://127.0.0.1:$ConfigPort/api/v1/auth/capabilities" -TimeoutSec 5
  Set-Content -Path $capabilitiesConfigOnlyPath -Value (($configOnlyCapabilities.data | ConvertTo-Json -Depth 6) + [Environment]::NewLine) -Encoding UTF8
} finally {
  Stop-TreeProcess $configOnlyProcess
}

try {
  $env:UMS_CONFIG_PATH = $isolatedConfig
  $env:UMS_SERVER_PORT = "$EnvPort"
  $env:UMS_CORS_ALLOWED_ORIGINS = 'https://admin.example.com'

  Remove-Item $envOverrideStdOut, $envOverrideStdErr -Force -ErrorAction SilentlyContinue
  $envOverrideProcess = Start-Process `
    -FilePath $serverExe `
    -WorkingDirectory $projectRoot `
    -PassThru `
    -WindowStyle Hidden `
    -RedirectStandardOutput $envOverrideStdOut `
    -RedirectStandardError $envOverrideStdErr

  Wait-UrlReady -Url "http://127.0.0.1:$EnvPort/health" -Label 'env-override health endpoint'
  Wait-UrlReady -Url "http://127.0.0.1:$EnvPort/health/ready" -Label 'env-override readiness endpoint'
  $envOverrideCapabilities = Invoke-RestMethod "http://127.0.0.1:$EnvPort/api/v1/auth/capabilities" -TimeoutSec 5
  Set-Content -Path $capabilitiesEnvOverridePath -Value (($envOverrideCapabilities.data | ConvertTo-Json -Depth 6) + [Environment]::NewLine) -Encoding UTF8

  $corsAllowed = Invoke-WebRequest `
    -Uri "http://127.0.0.1:$EnvPort/health" `
    -Headers @{ Origin = 'https://admin.example.com' } `
    -UseBasicParsing `
    -TimeoutSec 5
  $corsRejected = Invoke-WebRequest `
    -Uri "http://127.0.0.1:$EnvPort/health" `
    -Headers @{ Origin = 'http://localhost:3000' } `
    -UseBasicParsing `
    -TimeoutSec 5
} finally {
  Stop-TreeProcess $envOverrideProcess

  if ([string]::IsNullOrWhiteSpace($previousConfigPath)) {
    Remove-Item Env:UMS_CONFIG_PATH -ErrorAction SilentlyContinue
  } else {
    $env:UMS_CONFIG_PATH = $previousConfigPath
  }

  if ([string]::IsNullOrWhiteSpace($previousServerPort)) {
    Remove-Item Env:UMS_SERVER_PORT -ErrorAction SilentlyContinue
  } else {
    $env:UMS_SERVER_PORT = $previousServerPort
  }

  if ([string]::IsNullOrWhiteSpace($previousAllowedOrigins)) {
    Remove-Item Env:UMS_CORS_ALLOWED_ORIGINS -ErrorAction SilentlyContinue
  } else {
    $env:UMS_CORS_ALLOWED_ORIGINS = $previousAllowedOrigins
  }
}

$corsAllowedOrigin = $corsAllowed.Headers['Access-Control-Allow-Origin']
$corsRejectedOrigin = $corsRejected.Headers['Access-Control-Allow-Origin']

if ($corsAllowedOrigin -ne 'https://admin.example.com') {
  throw "expected env override CORS allow origin to be https://admin.example.com, got: $corsAllowedOrigin"
}
if (-not [string]::IsNullOrWhiteSpace($corsRejectedOrigin)) {
  throw "expected localhost origin to be excluded by env override, got: $corsRejectedOrigin"
}

$reportLines = @(
  '# Config And Env Isolation Drill',
  '',
  "- Generated at: $(Get-Date -Format 'yyyy-MM-dd HH:mm:ss zzz')",
  "- Source DB: $SourceDb",
  "- Isolated DB: $isolatedDb",
  "- Isolated config: $isolatedConfig",
  '',
  '## Verification Results',
  '',
  "- Base config default port: 8080",
  "- UMS_CONFIG_PATH isolated port: $ConfigPort",
  "- UMS_SERVER_PORT override port: $EnvPort",
  "- UMS_CORS_ALLOWED_ORIGINS override accepted origin: $corsAllowedOrigin",
  "- UMS_CORS_ALLOWED_ORIGINS override excluded origin: $(if ([string]::IsNullOrWhiteSpace($corsRejectedOrigin)) { 'none' } else { $corsRejectedOrigin })",
  "- auth capabilities with config-only override: $(($configOnlyCapabilities.data | ConvertTo-Json -Compress))",
  "- auth capabilities with env override: $(($envOverrideCapabilities.data | ConvertTo-Json -Compress))",
  '',
  '## Evidence Files',
  '',
  "- $(Split-Path $configOnlyStdOut -Leaf)",
  "- $(Split-Path $configOnlyStdErr -Leaf)",
  "- $(Split-Path $envOverrideStdOut -Leaf)",
  "- $(Split-Path $envOverrideStdErr -Leaf)",
  "- $(Split-Path $capabilitiesConfigOnlyPath -Leaf)",
  "- $(Split-Path $capabilitiesEnvOverridePath -Leaf)",
  "- $(Split-Path $isolatedConfig -Leaf)",
  ''
)

Set-Content -Path $reportPath -Value ($reportLines -join [Environment]::NewLine) -Encoding UTF8
Get-Content $reportPath