// Regenerates the OpenCode artifacts from the pristine upstream snapshot:
//
//   node scripts/generate.ts
//
// Inputs:  upstream/skills/**  +  .opencode/state/classification.json
// Outputs: skills/<name>/**    (verbatim, minus agents/openai.yaml; only skills whose
//                               classification artifacts include "skill:verbatim")
//          manifest.json       (plugin-injection manifest: id/name/description/autoinvoke/path)
//          docs/skill-mapping.md matrix section (between <!-- matrix:start/end --> markers)
//
// Deterministic: same inputs produce byte-identical outputs, so the nightly git diff is the
// affected-set report. Never hand-edit skills/ or the matrix section.
import { cpSync, existsSync, readFileSync, readdirSync, rmSync, statSync, writeFileSync } from "node:fs"
import path from "node:path"
import { fileURLToPath } from "node:url"
import { isUserInvoked, parseFrontmatter } from "./frontmatter.ts"

const root = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..")

export type ClassificationEntry = {
  name: string
  bucket: string
  classification: string
  user_invoked: boolean
  artifacts: string[]
  depends_on: string[]
  status: string
  rationale: string
}

export type ManifestEntry = {
  id: string
  name: string
  description: string
  autoinvoke: boolean
  path: string
}

export function loadClassification(file: string): ClassificationEntry[] {
  const doc = JSON.parse(readFileSync(file, "utf8"))
  return doc.skills as ClassificationEntry[]
}

function copySkillDir(from: string, to: string) {
  rmSync(to, { recursive: true, force: true })
  cpSync(from, to, {
    recursive: true,
    filter: (src) => {
      // strip Codex UI metadata dir; everything else ships verbatim
      const rel = path.relative(from, src)
      return rel !== "agents" && !rel.startsWith("agents" + path.sep)
    },
  })
}

export function buildSkills(opts: {
  upstreamSkills: string
  entries: ClassificationEntry[]
  skillsOut: string
}): ManifestEntry[] {
  const vendored = opts.entries.filter((e) => e.artifacts.includes("skill:verbatim"))
  const seen = new Set<string>()
  const manifest: ManifestEntry[] = []
  rmSync(opts.skillsOut, { recursive: true, force: true })

  for (const entry of vendored) {
    if (seen.has(entry.name)) throw new Error(`duplicate skill name across buckets: ${entry.name}`)
    seen.add(entry.name)
    const from = path.join(opts.upstreamSkills, entry.bucket, entry.name)
    const skillMd = path.join(from, "SKILL.md")
    if (!existsSync(skillMd)) {
      throw new Error(`classified skill missing upstream: ${entry.bucket}/${entry.name}`)
    }
    const to = path.join(opts.skillsOut, entry.name)
    copySkillDir(from, to)

    const { frontmatter } = parseFrontmatter(readFileSync(skillMd, "utf8"))
    const name = frontmatter.name || entry.name
    const description = frontmatter.description
    if (!frontmatter.name || !description) {
      throw new Error(`${entry.name}: SKILL.md frontmatter needs name and description`)
    }
    manifest.push({
      id: entry.name,
      name,
      description,
      autoinvoke: !isUserInvoked(frontmatter),
      path: `skills/${entry.name}/SKILL.md`,
    })
  }

  // fail on upstream skills nobody classified (sync-upstream normally adds needs-review entries)
  for (const bucket of existsSync(opts.upstreamSkills) ? readdirSync(opts.upstreamSkills) : []) {
    const bucketPath = path.join(opts.upstreamSkills, bucket)
    if (!statSync(bucketPath).isDirectory()) continue
    for (const name of readdirSync(bucketPath)) {
      if (!existsSync(path.join(bucketPath, name, "SKILL.md"))) continue
      if (!opts.entries.some((e) => e.name === name)) {
        throw new Error(`unclassified upstream skill: ${bucket}/${name} — run sync + review`)
      }
    }
  }

  manifest.sort((a, b) => a.id.localeCompare(b.id))
  return manifest
}

const BUCKET_SHORT: Record<string, string> = {
  engineering: "eng",
  productivity: "prod",
  misc: "misc",
  "in-progress": "in-prog",
  deprecated: "dep",
}

const cell = (value: string) => value.replace(/\|/g, "\\|")

export function renderMatrix(entries: ClassificationEntry[]): string {
  const lines = [
    "| Upstream skill | Bucket | DMI | Classification | Artifacts | Depends on | Status | Rationale |",
    "| --- | --- | --- | --- | --- | --- | --- | --- |",
  ]
  for (const e of entries) {
    lines.push(
      `| ${e.name} | ${BUCKET_SHORT[e.bucket] ?? e.bucket} | ${e.user_invoked ? "✓" : ""} | ` +
        `${e.classification} | ${cell(e.artifacts.join(", "))} | ${cell(e.depends_on.join(", "))} | ` +
        `${e.status} | ${cell(e.rationale)} |`,
    )
  }
  return lines.join("\n")
}

export function updateDocMatrix(docPath: string, matrix: string): void {
  const doc = readFileSync(docPath, "utf8")
  const start = "<!-- matrix:start -->"
  const end = "<!-- matrix:end -->"
  const i = doc.indexOf(start)
  const j = doc.indexOf(end)
  if (i === -1 || j === -1 || j < i) throw new Error(`${docPath}: missing matrix markers`)
  writeFileSync(docPath, `${doc.slice(0, i + start.length)}\n\n${matrix}\n\n${doc.slice(j)}`)
}

function main() {
  const classificationPath = path.join(root, ".opencode/state/classification.json")
  const docPath = path.join(root, "docs/skill-mapping.md")
  const entries = loadClassification(classificationPath)
  const manifest = buildSkills({
    upstreamSkills: path.join(root, "upstream/skills"),
    entries,
    skillsOut: path.join(root, "skills"),
  })
  writeFileSync(path.join(root, "manifest.json"), JSON.stringify(manifest, null, 2) + "\n")
  updateDocMatrix(docPath, renderMatrix(entries))
  const needsReview = entries.filter((e) => e.status === "needs-review").map((e) => e.name)
  console.log(
    `generated ${manifest.length} skills (${manifest.filter((m) => !m.autoinvoke).length} hidden from model), manifest.json, matrix in docs/skill-mapping.md` +
      (needsReview.length ? `\nWARNING needs-review: ${needsReview.join(", ")}` : ""),
  )
}

if (process.argv[1] === fileURLToPath(import.meta.url)) {
  try {
    main()
  } catch (err) {
    console.error((err as Error).message)
    process.exit(1)
  }
}