param(
  [string]$RepoPath = (Split-Path $PSScriptRoot -Parent),
  [bool]$AutoStash = $true,
  [bool]$Push = $true,
  [ValidateSet('abort','leave')][string]$OnConflict = 'leave'
)

function ExecGit {
  param([string[]]$ArgList, [bool]$IgnoreError = $false)
  Write-Host ("git " + ($ArgList -join ' ')) -ForegroundColor Cyan
  & git @ArgList
  $code = $LASTEXITCODE
  if (!$IgnoreError -and $code -ne 0) {
    throw ("Git command failed ({0}): git {1}" -f $code, ($ArgList -join ' '))
  }
  return $code
}

try {
  if (!(Test-Path $RepoPath)) { throw ("RepoPath not found: {0}" -f $RepoPath) }
  Set-Location $RepoPath

  # Ensure git is available
  ExecGit @('--version') $true | Out-Null

  $currentBranch = (& git rev-parse --abbrev-ref HEAD).Trim()
  if ([string]::IsNullOrWhiteSpace($currentBranch)) { throw 'Cannot resolve current branch' }
  Write-Host ("Current branch: {0}" -f $currentBranch) -ForegroundColor Green

  # Check worktree state
  $statusPorcelain = (& git status --porcelain)
  $hasChanges = -not [string]::IsNullOrWhiteSpace(($statusPorcelain -join ''))
  $stashMade = $false
  if ($hasChanges -and $AutoStash) {
    Write-Host 'Worktree not clean, auto-stash' -ForegroundColor Yellow
    ExecGit @('stash','push','-u','-m','auto-stash before merge-main-framework')
    $stashMade = $true
  } elseif ($hasChanges -and -not $AutoStash) {
    throw 'Worktree has uncommitted changes; commit or enable -AutoStash'
  }

  # Fetch remotes
  ExecGit @('fetch','--all','--prune')

  # Ensure remote branch exists
  $remoteRef = (& git ls-remote --heads origin main-framework)
  if ([string]::IsNullOrWhiteSpace(($remoteRef -join ''))) {
    throw 'Remote origin/main-framework not found. Check remote and branch name.'
  }

  Write-Host ("Merging origin/main-framework -> {0}" -f $currentBranch) -ForegroundColor Green
  $mergeCode = ExecGit @('merge','--no-ff','origin/main-framework') $true

  # Detect conflicts
  $unmerged = (& git ls-files -u)
  $hasConflicts = -not [string]::IsNullOrWhiteSpace(($unmerged -join ''))
  if ($hasConflicts) {
    Write-Host ('Conflicts detected. Strategy: {0}' -f $OnConflict) -ForegroundColor Yellow
    if ($OnConflict -eq 'abort') {
      ExecGit @('merge','--abort')
      if ($stashMade) {
        Write-Host 'Restoring stash (stash pop)' -ForegroundColor Yellow
        ExecGit @('stash','pop') $true | Out-Null
      }
      throw 'Merge aborted. Please resolve conflicts manually and retry.'
    } else {
      Write-Host 'Leaving conflict state for manual resolution:' -ForegroundColor Yellow
      Write-Host '- Edit conflicted files and run: git add <file>'
      Write-Host '- Then conclude: git commit'
      if ($stashMade) { Write-Host 'Note: run stash pop after resolving' -ForegroundColor Yellow }
      exit 2
    }
  }

  if ($mergeCode -eq 0) {
    Write-Host 'Merge completed.' -ForegroundColor Green
  } else {
    $st = (& git status)
    Write-Host $st
  }

  # Pop stash if any
  if ($stashMade) {
    Write-Host 'Restoring stash (stash pop)' -ForegroundColor Yellow
    ExecGit @('stash','pop') $true | Out-Null
  }

  # Push if requested
  if ($Push) {
    Write-Host 'Pushing to remote...' -ForegroundColor Green
    ExecGit @('push')
    Write-Host 'Push completed.' -ForegroundColor Green
  }

  Write-Host ("Done: origin/main-framework merged into {0}" -f $currentBranch) -ForegroundColor Green
} catch {
  Write-Error $_
  exit 1
}