#!/usr/bin/env node
// =============================================================
// ir-extract.mjs — the pivot (WHYNOT-WP-0002 · T05)
//
// Reads the local React designbook mirror (designbook/) and emits the
// technology-neutral IR (ir/): tokens, per-component contracts, and exemplars.
// One-way only: React → IR. Never hand-edit ir/tokens.json, ir/components/*,
// or ir/exemplars/* — they are regenerated here (`make ir`) and committed so a
// blueprint change shows up as a git diff. See ir/SCHEMA.md and
// .claude/rules/designbook-propagation.md.
//
// Source layout (a bundled .jsx ui-kit, not per-component .d.ts — see
// designbook/REACT_CANONICAL_DECISION.md):
//   designbook/_ds_manifest.json        → structured tokens[] + preview cards[]
//   designbook/ui_kits/<kit>/Atoms.jsx  → component fn signatures (props/defaults)
//   designbook/ui_kits/<kit>/Chrome.jsx → component fn signatures
//   designbook/preview/comp-*.html      → exemplar renders
// =============================================================
import { readFileSync, writeFileSync, mkdirSync, copyFileSync, rmSync, existsSync, readdirSync } from "node:fs";
import { createHash } from "node:crypto";
import { join, dirname } from "node:path";
import { fileURLToPath } from "node:url";

const REPO = join(dirname(fileURLToPath(import.meta.url)), "..");
const DESIGNBOOK = join(REPO, "designbook");
const IR = join(REPO, "ir");
const KIT = "whynot-control";

// Bump when the SHAPE of ir/manifest.json changes (consumers branch on this).
// Hash stability is governed here: any change that would alter existing hashes
// without a meaningful contract change must bump this so a consumer can tell a
// re-canonicalisation apart from a real design change. See ir/SCHEMA.md.
const MANIFEST_SCHEMA_VERSION = "1.0.0";

// Which ui-kit files hold reusable design-system components (NOT app screens/demo data).
const COMPONENT_SOURCES = ["Atoms.jsx", "Chrome.jsx"];

const log = (...a) => console.log(...a);
const kebab = (s) => s.replace(/([a-z0-9])([A-Z])/g, "$1-$2").toLowerCase();

// ---------- Tokens: _ds_manifest.json tokens[] → W3C DTCG ----------
// Each manifest token: { name:"--ink", value:"#0A0A0A", kind:"color", definedIn }.
// Group + DTCG $type are decided by name prefix (kind is a fallback hint).
const GROUP_BY_PREFIX = [
  ["--ff-", "fontFamily", "fontFamily"],
  ["--fs-", "fontSize", "dimension"],
  ["--lh-", "lineHeight", "number"],
  ["--tr-", "letterSpacing", "dimension"],
  ["--sp-", "space", "dimension"],
  ["--r-", "radius", "dimension"],
  ["--shadow-", "shadow", "shadow"],
];

function classify(name) {
  for (const [prefix, group, type] of GROUP_BY_PREFIX) {
    if (name.startsWith(prefix)) return { group, type };
  }
  return { group: "color", type: "color" }; // every remaining token is a colour
}

function extractTokens() {
  const manifest = JSON.parse(readFileSync(join(DESIGNBOOK, "_ds_manifest.json"), "utf8"));
  const tokens = manifest.tokens || [];
  // First pass: map each css var → its DTCG reference path {group.key}.
  const refOf = new Map();
  for (const t of tokens) {
    const { group } = classify(t.name);
    refOf.set(t.name, `${group}.${t.name.slice(2)}`);
  }
  // Second pass: build the nested DTCG tree.
  const out = {};
  for (const t of tokens) {
    const { group, type } = classify(t.name);
    const key = t.name.slice(2);
    out[group] ||= { $type: type };
    // Resolve `var(--x)` aliases to DTCG references; literals pass through.
    const aliasMatch = /^var\(\s*(--[A-Za-z0-9-]+)\s*\)$/.exec(t.value.trim());
    let value = t.value.replace(/\s+/g, " ").trim();
    if (aliasMatch && refOf.has(aliasMatch[1])) value = `{${refOf.get(aliasMatch[1])}}`;
    out[group][key] = { $value: value };
  }
  return out;
}

// ---------- Components: parse .jsx function signatures ----------
// Matches:  function Name({ a, b = 'x', children, onClick, style }) {  … }
const FN_RE = /function\s+([A-Z][A-Za-z0-9]*)\s*\(\s*\{([^}]*)\}\s*\)\s*\{/g;

function parseParams(raw) {
  // Split top-level commas (defaults here have no nested commas/objects).
  return raw.split(",").map((s) => s.trim()).filter(Boolean).map((p) => {
    const eq = p.indexOf("=");
    if (eq === -1) return { name: p.trim(), default: undefined };
    return { name: p.slice(0, eq).trim(), default: p.slice(eq + 1).trim() };
  });
}

// Collect enum values from `name === 'x'` / `name !== 'x'` comparisons in the body.
function enumValuesFor(name, body) {
  const re = new RegExp(`${name}\\s*[=!]==\\s*'([^']+)'`, "g");
  const vals = new Set();
  let m;
  while ((m = re.exec(body))) vals.add(m[1]);
  return [...vals];
}

function usedAsBoolean(name, body) {
  return new RegExp(`(if\\s*\\(\\s*${name}\\b|\\b${name}\\s*\\?|\\b${name}\\s*&&)`).test(body)
    && !new RegExp(`${name}\\s*===`).test(body);
}

function defaultLiteral(raw) {
  if (raw === undefined) return undefined;
  if (/^'[^']*'$/.test(raw) || /^"[^"]*"$/.test(raw)) return raw.slice(1, -1);
  if (/^-?\d+(\.\d+)?$/.test(raw)) return Number(raw);
  if (raw === "true" || raw === "false") return raw === "true";
  return raw; // expression default; keep verbatim
}

function propFor(param, body) {
  const { name, default: dflt } = param;
  const def = defaultLiteral(dflt);
  // children → slot, handled by caller. style/object & callbacks → non-portable.
  if (name === "style") {
    return { name, type: "object", attribute: false, portable: false,
      description: "React inline style override — not portable to an attribute." };
  }
  if (/^on[A-Z]/.test(name)) {
    return { name, type: "function", attribute: false, portable: false,
      description: "React callback prop — surface as an event on attribute-driven stacks." };
  }
  const prop = { name, attribute: kebab(name) };
  const enums = enumValuesFor(name, body);
  if (typeof def === "string" && enums.length) {
    prop.type = "enum";
    prop.enum = [...new Set([def, ...enums])];
  } else if (enums.length) {
    prop.type = "enum";
    prop.enum = enums;
  } else if (typeof def === "number") {
    prop.type = "number";
  } else if (typeof def === "boolean" || usedAsBoolean(name, body)) {
    prop.type = "boolean";
  } else {
    prop.type = "string";
  }
  if (def !== undefined) prop.default = def;
  return prop;
}

function bodyOf(src, startIdx) {
  // Return the balanced { … } body beginning at the first { at/after startIdx.
  let depth = 0, i = src.indexOf("{", startIdx);
  const begin = i;
  for (; i < src.length; i++) {
    if (src[i] === "{") depth++;
    else if (src[i] === "}" && --depth === 0) return src.slice(begin, i + 1);
  }
  return src.slice(begin);
}

// Map a component to a preview exemplar via the manifest cards (best-effort).
function buildExemplarIndex() {
  const manifest = JSON.parse(readFileSync(join(DESIGNBOOK, "_ds_manifest.json"), "utf8"));
  return (manifest.cards || []).filter((c) => c.group === "Components");
}

function matchExemplar(name, cards) {
  const n = name.toLowerCase();
  // direct hints: Button→comp-buttons, Tag/StageDot→comp-labels-tags, etc.
  const hint = { stagedot: "labels-tags", tag: "labels-tags", eyebrow: "labels-tags",
    pipelinestrip: "pipeline", topnav: "topnav", sidebar: "left-nav",
    pageheader: "topnav", button: "buttons" }[n];
  const want = hint || n;
  return cards.find((c) => c.path.includes(want)) || null;
}

function extractComponents() {
  const cards = buildExemplarIndex();
  const components = [];
  for (const file of COMPONENT_SOURCES) {
    const path = join(DESIGNBOOK, "ui_kits", KIT, file);
    if (!existsSync(path)) { log(`  (skip ${file} — not present)`); continue; }
    const src = readFileSync(path, "utf8");
    const group = file.replace(".jsx", "").toLowerCase();
    let m;
    FN_RE.lastIndex = 0;
    while ((m = FN_RE.exec(src))) {
      const name = m[1];
      const params = parseParams(m[2]);
      // FN_RE ends at the function body's opening brace; start the body scan there
      // (not at m.index, whose first `{` is the param-destructuring brace).
      const body = bodyOf(src, m.index + m[0].length - 1);
      const props = [];
      const slots = [];
      for (const p of params) {
        if (p.name === "children") { slots.push({ name: "default", description: "Default content." }); continue; }
        props.push(propFor(p, body));
      }
      const events = props.filter((p) => /^on[A-Z]/.test(p.name))
        .map((p) => ({ name: kebab(p.name.replace(/^on/, "wn-")), description: `Emitted for ${p.name}.` }));
      const variants = props.filter((p) => p.type === "enum")
        .map((p) => ({ axis: p.name, values: p.enum, ...(p.default ? { default: p.default } : {}) }));
      const card = matchExemplar(name, cards);
      const contract = {
        name,
        tag: `wn-${kebab(name)}`,
        group,
        description: `${name} — extracted from designbook ui_kits/${KIT}/${file}.`,
        props,
        ...(slots.length ? { slots } : {}),
        ...(events.length ? { events } : {}),
        ...(variants.length ? { variants } : {}),
        docsRef: `designbook/ui_kits/${KIT}/${file}`,
        ...(card ? { exemplarRef: `ir/exemplars/${name}.html` } : {}),
      };
      components.push({ contract, card });
    }
  }
  return components;
}

// ---------- Lightweight contract validation (invariants from ir/schema) ----------
function validateContract(c) {
  const errs = [];
  if (!/^[A-Z][A-Za-z0-9]*$/.test(c.name)) errs.push(`bad name ${c.name}`);
  if (!c.group || !c.description) errs.push(`${c.name}: missing group/description`);
  for (const p of c.props) {
    if (!p.name) errs.push(`${c.name}: prop without name`);
    if (p.type === "enum" && !(p.enum && p.enum.length)) errs.push(`${c.name}.${p.name}: enum without values`);
    if (!("attribute" in p)) errs.push(`${c.name}.${p.name}: missing attribute mapping`);
  }
  return errs;
}

// ---------- Manifest: deterministic content hashes (WHYNOT-WP-0003 · T03) ----------
// Canonicalise before hashing so the hash is invariant to key order and
// whitespace and sensitive ONLY to meaningful contract/token change.
function canonicalise(value) {
  if (Array.isArray(value)) return value.map(canonicalise);
  if (value && typeof value === "object") {
    return Object.keys(value).sort().reduce((acc, k) => {
      acc[k] = canonicalise(value[k]);
      return acc;
    }, {});
  }
  return value;
}

function contentHash(value) {
  return "sha256:" + createHash("sha256")
    .update(JSON.stringify(canonicalise(value)))
    .digest("hex")
    .slice(0, 16);
}

// Build ir/manifest.json. `generatedAt` is reused from the prior manifest when
// nothing hashed changed, so a no-op `make ir` does not churn the committed file.
function buildManifest(tokens, contracts) {
  const pkg = JSON.parse(readFileSync(join(REPO, "package.json"), "utf8"));
  const components = contracts
    .map((c) => ({ name: c.name, group: c.group, hash: contentHash(c) }))
    .sort((a, b) => a.name.localeCompare(b.name));
  const tokensHash = contentHash(tokens);

  const manifestPath = join(IR, "manifest.json");
  let generatedAt = new Date().toISOString();
  if (existsSync(manifestPath)) {
    try {
      const prev = JSON.parse(readFileSync(manifestPath, "utf8"));
      const unchanged =
        prev.schemaVersion === MANIFEST_SCHEMA_VERSION &&
        prev.designVersion === pkg.version &&
        prev.tokensHash === tokensHash &&
        JSON.stringify(prev.components) === JSON.stringify(components);
      if (unchanged && prev.generatedAt) generatedAt = prev.generatedAt;
    } catch { /* malformed prior manifest — regenerate fresh */ }
  }

  return {
    schemaVersion: MANIFEST_SCHEMA_VERSION,
    designVersion: pkg.version,
    generatedAt,
    tokensHash,
    components,
  };
}

// ---------- Index: human-readable catalog (WHYNOT-WP-0003 · T07) ----------
// A browsable view of a version — no clone or run needed. Generated from the
// same contracts the manifest hashes, so the two never disagree.
function buildIndex(manifest, contracts) {
  const byGroup = new Map();
  for (const c of contracts) {
    if (!byGroup.has(c.group)) byGroup.set(c.group, []);
    byGroup.get(c.group).push(c);
  }
  const hashOf = new Map(manifest.components.map((m) => [m.name, m.hash]));

  const lines = [];
  lines.push("<!-- GENERATED by scripts/ir-extract.mjs (make ir) — do not hand-edit. -->");
  lines.push(`# whynot-design IR catalog`);
  lines.push("");
  lines.push(`**designVersion** \`${manifest.designVersion}\` · **components** ${contracts.length} · **generated** ${manifest.generatedAt}`);
  lines.push("");
  lines.push("Machine-readable companion: [`manifest.json`](./manifest.json) (per-component + token hashes).");
  lines.push("");

  for (const group of [...byGroup.keys()].sort()) {
    lines.push(`## ${group}`);
    lines.push("");
    for (const c of byGroup.get(group).sort((a, b) => a.name.localeCompare(b.name))) {
      lines.push(`### ${c.name} \`<${c.tag}>\``);
      lines.push("");
      lines.push(c.description);
      lines.push("");
      const portableProps = (c.props || []).filter((p) => p.portable !== false);
      if (portableProps.length) {
        lines.push("| prop | attribute | type | default |");
        lines.push("| --- | --- | --- | --- |");
        for (const p of portableProps) {
          const type = p.type === "enum" ? `enum(${(p.enum || []).join(" \\| ")})` : p.type;
          lines.push(`| \`${p.name}\` | \`${p.attribute}\` | ${type} | ${p.default !== undefined ? `\`${p.default}\`` : "—"} |`);
        }
        lines.push("");
      }
      const nonPortable = (c.props || []).filter((p) => p.portable === false);
      if (nonPortable.length) {
        lines.push(`_Non-portable (React-only) props:_ ${nonPortable.map((p) => `\`${p.name}\``).join(", ")}.`);
        lines.push("");
      }
      if (c.slots) lines.push(`**Slots:** ${c.slots.map((s) => `\`${s.name}\``).join(", ")}  `);
      if (c.events) lines.push(`**Events:** ${c.events.map((e) => `\`${e.name}\``).join(", ")}  `);
      if (c.variants) lines.push(`**Variants:** ${c.variants.map((v) => `${v.axis} (${v.values.join("/")})`).join(", ")}  `);
      lines.push(`**Contract:** [\`components/${c.name}.json\`](./components/${c.name}.json) · **hash** \`${hashOf.get(c.name)}\`` +
        (c.exemplarRef ? ` · **exemplar:** [\`exemplars/${c.name}.html\`](./exemplars/${c.name}.html)` : ""));
      lines.push("");
    }
  }
  return lines.join("\n");
}

// ---------- Emit ----------
function resetDir(dir) {
  if (existsSync(dir)) for (const f of readdirSync(dir)) rmSync(join(dir, f), { recursive: true, force: true });
  else mkdirSync(dir, { recursive: true });
}

function main() {
  if (!existsSync(join(DESIGNBOOK, "_ds_manifest.json"))) {
    console.error("No designbook/_ds_manifest.json — run `make designbook-pull` first.");
    process.exit(2);
  }
  mkdirSync(IR, { recursive: true });

  log("Tokens → ir/tokens.json");
  const tokens = extractTokens();
  writeFileSync(join(IR, "tokens.json"), JSON.stringify(tokens, null, 2) + "\n");
  const tokenCount = Object.values(tokens).reduce((n, g) => n + Object.keys(g).filter((k) => k !== "$type").length, 0);
  log(`  ${tokenCount} tokens in ${Object.keys(tokens).length} groups`);

  log("Components → ir/components/<Name>.json");
  const comps = extractComponents();
  resetDir(join(IR, "components"));
  resetDir(join(IR, "exemplars"));
  const allErrs = [];
  for (const { contract, card } of comps) {
    allErrs.push(...validateContract(contract));
    writeFileSync(join(IR, "components", `${contract.name}.json`), JSON.stringify(contract, null, 2) + "\n");
    if (card) {
      const srcHtml = join(DESIGNBOOK, card.path);
      if (existsSync(srcHtml)) copyFileSync(srcHtml, join(IR, "exemplars", `${contract.name}.html`));
    }
  }
  log(`  ${comps.length} components, ${comps.filter((c) => c.card).length} with exemplars`);

  if (allErrs.length) {
    console.error("\nContract validation errors:");
    for (const e of allErrs) console.error("  - " + e);
    process.exit(5);
  }

  log("Manifest → ir/manifest.json");
  const manifest = buildManifest(tokens, comps.map((c) => c.contract));
  writeFileSync(join(IR, "manifest.json"), JSON.stringify(manifest, null, 2) + "\n");
  log(`  designVersion ${manifest.designVersion}, ${manifest.components.length} components, tokensHash ${manifest.tokensHash}`);

  log("Index → ir/INDEX.md");
  writeFileSync(join(IR, "INDEX.md"), buildIndex(manifest, comps.map((c) => c.contract)));
  log(`  catalog for ${manifest.components.length} components`);

  log("\nIR extracted. Review the ir/ git diff (the blueprint change).");
}

main();