#!/usr/bin/env node

/**
 * Manifest scanner CLI (v5 N2) — produce a ranked list of every token source
 * loaded for a given repo path. Built on top of readActiveConfig so the source
 * inventory is identical to whats-active; this CLI flattens and ranks them.
 *
 * Output JSON shape:
 *   {
 *     meta: { repoPath, generatedAt, durationMs },
 *     sources: [
 *       { kind: 'claude-md'|'skill'|'rule'|'agent'|'output-style'|'mcp-server'|'hook',
 *         name: string, source: string, estimated_tokens: number,
 *         loadPattern: 'always'|'on-demand'|'external'|'unknown',
 *         survivesCompaction: 'yes'|'no'|'n/a',
 *         derivationConfidence: 'confirmed'|'inferred' },
 *       ...
 *     ],
 *     summary: {
 *       always:   { tokens, count },   // enter context every turn before you type
 *       onDemand: { tokens, count },   // loaded on invoke / on file read
 *       external: { tokens, count },   // run outside the context window (hooks)
 *       unknown:  { tokens, count },
 *     },
 *     total: <sum of sources.estimated_tokens>
 *   }
 *
 * v5.6 B — load-pattern accounting. Sources are component-level: the coarse
 * "plugin" roll-up was dropped because a plugin's contributions (skills, rules,
 * agents, output styles, hooks, MCP) are each enumerated once on their own —
 * keeping the roll-up double-counted them and corrupted the always-loaded
 * subtotal. Every record now carries the load pattern derived from the
 * published Claude Code loading model (deriveLoadPattern).
 *
 * Usage:
 *   node manifest.mjs [path] [--json] [--output-file <path>]
 *
 * Exit codes: 0=ok, 3=unrecoverable error.
 * Zero external dependencies.
 */

import { resolve } from 'node:path';
import { writeFile, stat } from 'node:fs/promises';
import { readActiveConfig, deriveLoadPattern } from './lib/active-config-reader.mjs';

// CLAUDE.md cascade files are all discovered by walking UP from the repo, so
// each one is always-loaded; the scope only changes the derivation confidence.
const CLAUDE_MD_SCOPE_KIND = {
  project: 'claude-md-root',
  local: 'claude-md-root',
  user: 'claude-md-user',
  managed: 'claude-md-managed',
  import: 'claude-md-import',
};

/** Spread the three load-pattern fields onto a source record. */
function withLoadPattern(record, lp) {
  return {
    ...record,
    loadPattern: lp.loadPattern,
    survivesCompaction: lp.survivesCompaction,
    derivationConfidence: lp.derivationConfidence,
  };
}

const sourceLabel = (item, fallback) =>
  item.pluginName ? `plugin:${item.pluginName}` : item.source || fallback;

/**
 * Flatten an activeConfig snapshot into a single ranked array of sources, each
 * tagged with its load pattern, plus a load-pattern summary.
 */
export function buildManifest(activeConfig) {
  const sources = [];

  for (const f of activeConfig.claudeMd?.files || []) {
    const tokens = estimateClaudeMdEntryTokens(f, activeConfig);
    const kind = CLAUDE_MD_SCOPE_KIND[f.scope] || 'claude-md-root';
    sources.push(withLoadPattern({
      kind: 'claude-md',
      name: f.path,
      source: f.scope,
      estimated_tokens: tokens,
    }, deriveLoadPattern(kind)));
  }

  // Skills: the measured tokens are the skill BODY (full file), paid on invoke.
  // The always-loaded part (name+description listing) is small and tracked
  // separately (skill-listing-budget / posture), so the body is tagged
  // on-demand here rather than inflating the always-loaded subtotal.
  for (const s of activeConfig.skills || []) {
    sources.push(withLoadPattern({
      kind: 'skill',
      name: s.name,
      source: sourceLabel(s, 'user'),
      estimated_tokens: s.estimatedTokens || 0,
    }, deriveLoadPattern('skill-body')));
  }

  // Rules / agents / output styles — the foundation enumeration already derived
  // the load pattern (rules vary by `scoped`), so propagate it verbatim.
  for (const r of activeConfig.rules || []) {
    sources.push(withLoadPattern({
      kind: 'rule',
      name: r.name,
      source: sourceLabel(r, 'project'),
      estimated_tokens: r.estimatedTokens || 0,
    }, r));
  }

  for (const a of activeConfig.agents || []) {
    sources.push(withLoadPattern({
      kind: 'agent',
      name: a.name,
      source: sourceLabel(a, 'project'),
      estimated_tokens: a.estimatedTokens || 0,
    }, a));
  }

  for (const o of activeConfig.outputStyles || []) {
    sources.push(withLoadPattern({
      kind: 'output-style',
      name: o.name,
      source: sourceLabel(o, 'project'),
      estimated_tokens: o.estimatedTokens || 0,
    }, o));
  }

  for (const m of activeConfig.mcpServers || []) {
    if (m && m.enabled === false) continue;
    sources.push(withLoadPattern({
      kind: 'mcp-server',
      name: m.name,
      source: m.source || 'unknown',
      estimated_tokens: m.estimatedTokens || 0,
    }, deriveLoadPattern('mcp')));
  }

  for (const h of activeConfig.hooks || []) {
    sources.push(withLoadPattern({
      kind: 'hook',
      name: `${h.event}${h.matcher ? `:${h.matcher}` : ''}`,
      source: h.source || h.sourcePath || 'unknown',
      estimated_tokens: h.estimatedTokens || 0,
    }, deriveLoadPattern('hook')));
  }

  sources.sort((a, b) => b.estimated_tokens - a.estimated_tokens);
  const total = sources.reduce((s, x) => s + (x.estimated_tokens || 0), 0);
  const summary = summarizeByLoadPattern(sources);
  return { sources, total, summary };
}

/**
 * Bucket sources by load pattern into {tokens, count} subtotals. The `always`
 * bucket is the headline: tokens that enter context every turn before the user
 * types anything.
 */
export function summarizeByLoadPattern(sources) {
  const mk = () => ({ tokens: 0, count: 0 });
  const summary = { always: mk(), onDemand: mk(), external: mk(), unknown: mk() };
  const BUCKET = { always: 'always', 'on-demand': 'onDemand', external: 'external' };
  for (const s of sources) {
    const key = BUCKET[s.loadPattern] || 'unknown';
    summary[key].tokens += s.estimated_tokens || 0;
    summary[key].count += 1;
  }
  return summary;
}

/**
 * Source strings (the `source` field buildManifest stamps) that belong to the
 * SHARED GLOBAL layer — config paid once per machine and identical in every
 * repo: the global ~/.claude CLAUDE.md (`user`) and managed enterprise policy
 * (`managed`). Installed plugins are also shared but are matched by the
 * `plugin:` prefix below, not by this set.
 *
 * Deliberately NOT here: `~/.claude.json:projects`. Although that file lives in
 * HOME, `readClaudeJsonProjectSlice` returns the slice keyed to the SPECIFIC
 * repo path — those MCP servers are per-repo, load only in their own project,
 * and differ across repos, so they are a delta (folding them into the
 * once-counted shared layer would drop every repo's slice but the first). The
 * only machine-global MCP is plugin-provided (caught by the `plugin:` prefix).
 */
const SHARED_GLOBAL_SOURCES = Object.freeze(new Set(['user', 'managed']));

/**
 * Classify one manifest source as part of the once-counted shared global layer
 * or a per-repo delta (v5.9 B2b). Anything not positively identified as global
 * (project / local / .mcp.json / ~/.claude.json:projects / @import / unrecognized)
 * falls to `delta`, so a source is never silently folded into the shared layer —
 * a wrong fold would HIDE machine-wide cost, whereas a wrong delta is at worst
 * attributed visibly to a repo.
 * @param {string} source
 * @returns {'shared'|'delta'}
 */
export function classifyOwnership(source) {
  if (typeof source === 'string') {
    if (source.startsWith('plugin:')) return 'shared'; // installed plugins are machine-global
    if (SHARED_GLOBAL_SOURCES.has(source)) return 'shared';
  }
  return 'delta';
}

/**
 * Partition manifest sources by ownership for the machine-wide token roll-up,
 * returning two load-pattern summaries in the exact shape `summarizeByLoadPattern`
 * emits ({always,onDemand,external,unknown:{tokens,count}}), so the campaign
 * ledger setters (`setSharedGlobal` / `setRepoTokens`) consume them verbatim.
 *
 *  - `shared`: the global layer, identical across repos — set ONCE on the ledger
 *    root so the roll-up counts it exactly once (the structural double-count guard).
 *  - `delta`:  this repo's own project/local contribution beyond the shared layer.
 *
 * The split is total: every source lands in exactly one layer.
 * @param {Array<{source:string, loadPattern:string, estimated_tokens:number}>} sources
 * @returns {{shared:object, delta:object}}
 */
export function splitManifestByOwnership(sources) {
  const shared = [];
  const delta = [];
  for (const s of sources || []) {
    (classifyOwnership(s.source) === 'shared' ? shared : delta).push(s);
  }
  return { shared: summarizeByLoadPattern(shared), delta: summarizeByLoadPattern(delta) };
}

/**
 * Distribute the cascade-level estimated tokens across the individual files
 * proportional to their byte size. claudeMd.estimatedTokens is computed for
 * the cascade as a whole, but for ranking we want per-file figures.
 */
function estimateClaudeMdEntryTokens(file, activeConfig) {
  const totalBytes = activeConfig.claudeMd?.totalBytes || 0;
  const totalTokens = activeConfig.claudeMd?.estimatedTokens || 0;
  if (totalBytes === 0 || totalTokens === 0) return 0;
  const share = (file.bytes || 0) / totalBytes;
  return Math.round(totalTokens * share);
}

async function main() {
  const args = process.argv.slice(2);
  let targetPath = '.';
  let outputFile = null;
  let jsonMode = false;
  // --raw is accepted for CLI surface consistency but is a no-op here:
  // manifest produces a token-source inventory, not findings.
  let rawMode = false;

  for (let i = 0; i < args.length; i++) {
    if (args[i] === '--json') jsonMode = true;
    else if (args[i] === '--raw') rawMode = true;
    else if (args[i] === '--output-file' && args[i + 1]) outputFile = args[++i];
    else if (!args[i].startsWith('-')) targetPath = args[i];
  }

  const absPath = resolve(targetPath);
  try {
    const s = await stat(absPath);
    if (!s.isDirectory()) {
      process.stderr.write(`Error: ${absPath} is not a directory\n`);
      process.exit(3);
    }
  } catch {
    process.stderr.write(`Error: path does not exist: ${absPath}\n`);
    process.exit(3);
  }

  const start = Date.now();
  const activeConfig = await readActiveConfig(absPath, { verbose: true });
  const manifest = buildManifest(activeConfig);

  const output = {
    meta: {
      tool: 'config-audit:manifest',
      repoPath: absPath,
      generatedAt: new Date().toISOString(),
      durationMs: Date.now() - start,
    },
    sources: manifest.sources,
    summary: manifest.summary,
    total: manifest.total,
  };

  const json = JSON.stringify(output, null, 2);

  if (outputFile) {
    await writeFile(outputFile, json, 'utf-8');
  }

  if (jsonMode || rawMode || !outputFile) {
    process.stdout.write(json + '\n');
  }
}

const isDirectRun = process.argv[1] && resolve(process.argv[1]) === resolve(new URL(import.meta.url).pathname);
if (isDirectRun) {
  main().catch(err => {
    process.stderr.write(`Fatal: ${err.message}\n`);
    process.exit(3);
  });
}