# Refresh the local mirror of the Curabis BCQuality knowledge base.
#
# Mirrors three layers from https://github.com/Curabis/BCQuality:
#   custom/    - Curabis org-specific rules   (ALWAYS read in full each session)
#   community/ - BC community patterns         (loaded on relevance via INDEX.md)
#   microsoft/ - platform guardrails           (loaded on relevance via INDEX.md)
#
# The upstream file list is discovered dynamically from the GitHub tree API, so
# new/removed upstream files propagate automatically - nothing is hardcoded.
# After downloading, an INDEX.md is generated (one line per file, with domain +
# keywords from each file's frontmatter) so an agent can scan and pull only the
# files relevant to a task instead of loading all ~100 every session.
#
# Run periodically, then review the diff and commit:
#   pwsh .github/.agents/sync-bcquality-knowledge.ps1

$ErrorActionPreference = 'Stop'

$repo    = 'Curabis/BCQuality'
$branch  = 'main'
$dest    = Join-Path $PSScriptRoot 'bcquality-knowledge'
$staging = "$dest.tmp"
$rawBase = "https://raw.githubusercontent.com/$repo/$branch"
$treeUrl = "https://api.github.com/repos/$repo/git/trees/$branch" + '?recursive=1'

# Upstream path prefix -> local layer folder
$layerMap = [ordered]@{
    'custom/knowledge/'    = 'custom'
    'community/knowledge/' = 'community'
    'microsoft/knowledge/' = 'microsoft'
}

function Get-Frontmatter {
    param([string]$Path)
    $lines = Get-Content -Path $Path
    $fm = @{}
    if ($lines.Count -eq 0 -or $lines[0].Trim() -ne '---') { return $fm }
    for ($i = 1; $i -lt $lines.Count; $i++) {
        if ($lines[$i].Trim() -eq '---') { break }
        if ($lines[$i] -match '^\s*([\w-]+):\s*(.*)$') {
            $fm[$matches[1]] = $matches[2].Trim()
        }
    }
    return $fm
}

Write-Host "Fetching file tree from $repo@$branch ..."
$headers = @{ 'User-Agent' = 'wareco-bcquality-sync'; 'Accept' = 'application/vnd.github+json' }
$tree = (Invoke-RestMethod -Uri $treeUrl -Headers $headers).tree

# Build the download worklist from the tree
$files = @()
foreach ($node in $tree) {
    if ($node.type -ne 'blob') { continue }
    if ($node.path -notlike '*.md') { continue }
    foreach ($prefix in $layerMap.Keys) {
        if ($node.path.StartsWith($prefix)) {
            $relative = $node.path.Substring($prefix.Length)   # e.g. performance/avoid-commit-inside-loops.md
            $files += [pscustomobject]@{
                Url       = "$rawBase/$($node.path)"
                Layer     = $layerMap[$prefix]
                Relative  = $relative
                LocalPath = Join-Path $staging (Join-Path $layerMap[$prefix] $relative)
            }
            break
        }
    }
}

if ($files.Count -eq 0) { throw 'No knowledge files found in upstream tree - aborting.' }

# Download into a staging folder so a mid-run failure never wipes the live copy
if (Test-Path $staging) { Remove-Item -Recurse -Force $staging }
New-Item -ItemType Directory -Force $staging | Out-Null

Write-Host "Downloading $($files.Count) knowledge files ..."
$rc = 0
foreach ($f in $files) {
    New-Item -ItemType Directory -Force (Split-Path $f.LocalPath) | Out-Null
    try {
        Invoke-WebRequest -Uri $f.Url -OutFile $f.LocalPath -UseBasicParsing -ErrorAction Stop
        Write-Host "OK   $($f.Layer)/$($f.Relative)"
    } catch {
        Write-Error "FAIL $($f.Layer)/$($f.Relative)"
        $rc = 1
    }
}

# Generate INDEX.md (relevance index for all layers)
Write-Host "Generating INDEX.md ..."
$idx = [System.Collections.Generic.List[string]]::new()
$idx.Add('# BCQuality Knowledge Index')
$idx.Add('')
$idx.Add('<!-- Generated by sync-bcquality-knowledge.ps1 - do not edit by hand. -->')
$idx.Add('')
$idx.Add('Layers: `custom` is ALWAYS read in full each session. For `community` and')
$idx.Add('`microsoft`, scan this index and read only the files whose domain/keywords')
$idx.Add('match the task at hand.')
$idx.Add('')

foreach ($layer in @('custom', 'community', 'microsoft')) {
    $layerFiles = $files | Where-Object { $_.Layer -eq $layer } | Sort-Object Relative
    if (-not $layerFiles) { continue }
    $note = if ($layer -eq 'custom') { ' (always-on)' } else { ' (load on relevance)' }
    $idx.Add("## $layer$note")
    $idx.Add('')
    foreach ($f in $layerFiles) {
        $fm = Get-Frontmatter $f.LocalPath
        $domain = if ($fm.ContainsKey('domain')) { $fm['domain'] } else { '' }
        $keywords = if ($fm.ContainsKey('keywords')) { $fm['keywords'].Trim('[', ']') } else { '' }
        $rel = $f.Relative -replace '\.md$', ''
        $idx.Add("- ``$layer/$rel`` - domain: $domain; keywords: $keywords")
    }
    $idx.Add('')
}
Set-Content -Path (Join-Path $staging 'INDEX.md') -Value $idx -Encoding utf8

# Swap staging into place
if (Test-Path $dest) { Remove-Item -Recurse -Force $dest }
Rename-Item -Path $staging -NewName (Split-Path $dest -Leaf)

Write-Host ''
Write-Host "Done. $($files.Count) files across $($layerMap.Count) layers."
Write-Host "Review changes with: git diff $dest"
exit $rc