import fs from 'node:fs';
import os from 'node:os';
import path from 'node:path';
import { performance } from 'node:perf_hooks';
import { CondensedGraph } from '../src/core/CondensedGraph.js';
import { ShardedSnapshotBuilder } from '../src/core/shards/ShardedSnapshotBuilder.js';
import { ShardedSnapshot } from '../src/core/shards/ShardedSnapshot.js';
import { FileShardStorage } from '../src/core/shards/FileShardStorage.js';
import { DeltaShardBinary } from '../src/core/shards/DeltaShardBinary.js';
import { WaveletShardBinary } from '../src/core/shards/WaveletShardBinary.js';

function parseArgs(argv) {
  const args = new Map();
  for (let i = 2; i < argv.length; i++) {
    const value = argv[i];
    if (!value.startsWith('--')) continue;
    const [key, inline] = value.slice(2).split('=');
    if (inline !== undefined) {
      args.set(key, inline);
      continue;
    }
    const next = argv[i + 1];
    if (next && !next.startsWith('--')) {
      args.set(key, next);
      i++;
    } else {
      args.set(key, true);
    }
  }
  return args;
}

function makeRng(seed) {
  let state = seed >>> 0;
  return () => {
    state = (1664525 * state + 1013904223) >>> 0;
    return state / 0x100000000;
  };
}

function randInt(rng, max) {
  return Math.floor(rng() * max);
}

function shuffleWithRng(items, rng) {
  for (let i = items.length - 1; i > 0; i--) {
    const j = Math.floor(rng() * (i + 1));
    [items[i], items[j]] = [items[j], items[i]];
  }
  return items;
}

function buildSnapshot(graph, bucketSize, dir, shardMode, componentRelations, chainGroupTargetSize, chainGroupTargetCount) {
  const builder = new ShardedSnapshotBuilder({
    bucketSize,
    includeDirections: ['out', 'in'],
    shardMode,
    componentRelations,
    chainGroupTargetSize,
    chainGroupTargetCount
  });
  const manifest = builder.build(graph, dir);
  const storage = new FileShardStorage(dir);
  const snapshot = new ShardedSnapshot(manifest, storage, { cacheLimit: 64, recentLimit: 256 });
  snapshot.initializeSync();
  return { snapshot, manifest, storage };
}

function buildDeltaLayer(snapshot, relationIds, deltaEdges, rng, dir) {
  const buckets = new Map();
  const relationList = relationIds.filter((relId) => Number.isFinite(relId));
  let addCount = 0;
  let removeCount = 0;
  for (let i = 0; i < deltaEdges; i++) {
    const relId = relationList[i % relationList.length];
    const srcId = randInt(rng, snapshot.nodeCount);
    const shardMeta = snapshot._selectShardMeta(relId, 'out', srcId);
    if (!shardMeta) continue;
    const localSource = snapshot._localSource(srcId, shardMeta);
    const key = shardMeta.cacheKey;
    let entry = buckets.get(key);
    if (!entry) {
      entry = { shardMeta, additions: [], removals: [] };
      buckets.set(key, entry);
    }

    const edges = snapshot.getOutEdgesSync(srcId, relId);
    if (edges.length && rng() < 0.5) {
      const edge = edges[randInt(rng, edges.length)];
      entry.removals.push({ srcLocal: localSource, otherId: edge.dst });
      removeCount++;
    } else {
      const dstId = randInt(rng, snapshot.nodeCount);
      entry.additions.push({ srcLocal: localSource, otherId: dstId, possBits: 65535, relBits: 65535 });
      addCount++;
    }
  }

  fs.mkdirSync(dir, { recursive: true });
  const shards = [];
  for (const entry of buckets.values()) {
    const shardKey = `delta-${entry.shardMeta.key}`;
    const buffer = DeltaShardBinary.serialize({
      relationId: entry.shardMeta.relationId,
      direction: entry.shardMeta.direction,
      rangeStart: entry.shardMeta.rangeStart,
      rangeEnd: entry.shardMeta.rangeEnd,
      nodeCount: snapshot.nodeCount,
      additions: entry.additions,
      removals: entry.removals
    });
    fs.writeFileSync(path.join(dir, shardKey), new Uint8Array(buffer));
    shards.push({
      key: shardKey,
      relationId: entry.shardMeta.relationId,
      direction: entry.shardMeta.direction,
      rangeStart: entry.shardMeta.rangeStart,
      rangeEnd: entry.shardMeta.rangeEnd,
      cacheKey: entry.shardMeta.cacheKey
    });
  }
  return { shards, storage: new FileShardStorage(dir), addCount, removeCount };
}

function timeQueries(runQuery, queries) {
  const start = performance.now();
  let hits = 0;
  for (const query of queries) {
    if (runQuery(query)) hits++;
  }
  const duration = performance.now() - start;
  return { duration, hits };
}

function sumDeltaBytes(dir) {
  let total = 0;
  const entries = fs.readdirSync(dir, { withFileTypes: true });
  for (const entry of entries) {
    if (!entry.isFile()) continue;
    total += fs.statSync(path.join(dir, entry.name)).size;
  }
  return total;
}

function sumShardBytes(dir, manifest) {
  let total = 0;
  if (manifest.nodeTableKey) {
    const nodeTablePath = path.join(dir, manifest.nodeTableKey);
    if (fs.existsSync(nodeTablePath)) total += fs.statSync(nodeTablePath).size;
  }
  if (manifest.componentKey) {
    const componentPath = path.join(dir, manifest.componentKey);
    if (fs.existsSync(componentPath)) total += fs.statSync(componentPath).size;
  }
  for (const shard of manifest.shards || []) {
    const shardPath = path.join(dir, shard.key);
    if (fs.existsSync(shardPath)) total += fs.statSync(shardPath).size;
  }
  return total;
}

function shardSizeStats(dir, manifest) {
  const sizes = [];
  for (const shard of manifest.shards || []) {
    const shardPath = path.join(dir, shard.key);
    if (fs.existsSync(shardPath)) sizes.push(fs.statSync(shardPath).size);
  }
  sizes.sort((a, b) => a - b);
  if (!sizes.length) return { p50: 0, p95: 0, p99: 0, max: 0, min: 0 };
  const pct = (p) => sizes[Math.min(sizes.length - 1, Math.floor(p * sizes.length))];
  return {
    p50: pct(0.5),
    p95: pct(0.95),
    p99: pct(0.99),
    max: sizes[sizes.length - 1],
    min: sizes[0]
  };
}

function countShardFiles(manifest) {
  let total = 0;
  if (manifest.nodeTableKey) total += 1;
  if (manifest.componentKey) total += 1;
  total += (manifest.shards || []).length;
  return total;
}

function scenarioOwnerDirect(size, rng) {
  const graph = new CondensedGraph();
  const users = [];
  const resources = [];
  for (let i = 0; i < size; i++) {
    users.push(graph._ensureNode(`user:${i}`));
    resources.push(graph._ensureNode(`resource:${i}`));
  }
  for (let i = 0; i < size; i++) {
    graph.addEdge(users[i], 'owner', resources[i]);
  }
  const queries = [];
  for (let i = 0; i < Math.min(2000, size * 2); i++) {
    const id = randInt(rng, size);
    queries.push({ userId: users[id], resourceId: resources[id], expect: true });
  }
  for (let i = 0; i < Math.min(2000, size * 2); i++) {
    const id = randInt(rng, size);
    queries.push({ userId: users[id], resourceId: resources[(id + 1) % size], expect: false });
  }
  return { graph, queries: shuffleWithRng(queries, rng), relations: ['owner'] };
}

function scenarioTupleToUserset(size, rng) {
  const graph = new CondensedGraph();
  const groupCount = Math.max(1, Math.floor(size / 10));
  const users = [];
  const groups = [];
  const resources = [];
  for (let i = 0; i < size; i++) users.push(graph._ensureNode(`user:${i}`));
  for (let i = 0; i < groupCount; i++) groups.push(graph._ensureNode(`group:${i}`));
  for (let i = 0; i < groupCount; i++) resources.push(graph._ensureNode(`resource:${i}`));
  for (let i = 0; i < size; i++) {
    const groupId = i % groupCount;
    graph.addEdge(users[i], 'member', groups[groupId]);
  }
  for (let i = 0; i < groupCount; i++) {
    graph.addEdge(groups[i], 'group_access', resources[i]);
  }
  const queries = [];
  for (let i = 0; i < Math.min(2000, size); i++) {
    const userId = randInt(rng, size);
    const groupId = userId % groupCount;
    queries.push({ userId: users[userId], resourceId: resources[groupId], expect: true });
  }
  for (let i = 0; i < Math.min(2000, size); i++) {
    const userId = randInt(rng, size);
    const groupId = (userId + 1) % groupCount;
    queries.push({ userId: users[userId], resourceId: resources[groupId], expect: false });
  }
  return { graph, queries: shuffleWithRng(queries, rng), relations: ['member', 'group_access'] };
}

function scenarioBlockedUnless(size, rng) {
  const graph = new CondensedGraph();
  const users = [];
  const resources = [];
  for (let i = 0; i < size; i++) {
    users.push(graph._ensureNode(`user:${i}`));
    resources.push(graph._ensureNode(`resource:${i}`));
  }
  for (let i = 0; i < size; i++) {
    graph.addEdge(users[i], 'viewer', resources[i]);
    if (i % 5 === 0) graph.addEdge(users[i], 'blocked', resources[i]);
  }
  const queries = [];
  for (let i = 0; i < Math.min(2000, size * 2); i++) {
    const id = randInt(rng, size);
    queries.push({ userId: users[id], resourceId: resources[id], expect: id % 5 !== 0 });
  }
  for (let i = 0; i < Math.min(2000, size * 2); i++) {
    const id = randInt(rng, size);
    queries.push({ userId: users[id], resourceId: resources[(id + 1) % size], expect: false });
  }
  return { graph, queries: shuffleWithRng(queries, rng), relations: ['viewer', 'blocked'] };
}

function scenarioRiskComparator(size, rng) {
  const graph = new CondensedGraph();
  const users = [];
  const resources = [];
  for (let i = 0; i < size; i++) {
    users.push(graph._ensureNode(`user:${i}`));
    resources.push(graph._ensureNode(`resource:${i}`));
  }
  for (let i = 0; i < size; i++) {
    graph.addEdge(users[i], 'risk_score', resources[i], 1.0, { value: (i % 100) / 100 });
    graph.addEdge(resources[i], 'risk_limit', resources[i], 1.0, { value: 0.6 });
  }
  const queries = [];
  for (let i = 0; i < Math.min(2000, size); i++) {
    const id = randInt(rng, size);
    queries.push({ userId: users[id], resourceId: resources[id], expect: (id % 100) / 100 <= 0.6 });
  }
  return { graph, queries: shuffleWithRng(queries, rng), relations: ['risk_score', 'risk_limit'] };
}

function evaluateOwner(snapshot, relId, query) {
  return snapshot.findEdgeSync(query.userId, relId, query.resourceId) !== null;
}

function evaluateTupleToUserset(snapshot, relIds, query) {
  const groupAccessRel = relIds.group_access;
  const memberRel = relIds.member;
  const groupEdges = snapshot.getInEdgesSync(query.resourceId, groupAccessRel);
  for (const groupEdge of groupEdges) {
    const groupId = groupEdge.src;
    const memberEdge = snapshot.findEdgeSync(query.userId, memberRel, groupId);
    if (memberEdge) return true;
  }
  return false;
}

function evaluateBlocked(snapshot, relIds, query) {
  const viewerRel = relIds.viewer;
  const blockedRel = relIds.blocked;
  const viewer = snapshot.findEdgeSync(query.userId, viewerRel, query.resourceId);
  if (!viewer) return false;
  const blocked = snapshot.findEdgeSync(query.userId, blockedRel, query.resourceId);
  return !blocked;
}

function evaluateRisk(snapshot, relIds, query) {
  const scoreRel = relIds.risk_score;
  const limitRel = relIds.risk_limit;
  const scoreEdge = snapshot.findEdgeSync(query.userId, scoreRel, query.resourceId);
  if (!scoreEdge) return false;
  const limitEdge = snapshot.findEdgeSync(query.resourceId, limitRel, query.resourceId);
  if (!limitEdge) return false;
  return scoreEdge.value <= limitEdge.value;
}

const scenarios = [
  { name: 'owner_direct', build: scenarioOwnerDirect, eval: (snapshot, relIds, query) => evaluateOwner(snapshot, relIds.owner, query) },
  { name: 'group_tuple_to_userset', build: scenarioTupleToUserset, eval: (snapshot, relIds, query) => evaluateTupleToUserset(snapshot, relIds, query) },
  { name: 'blocked_unless', build: scenarioBlockedUnless, eval: (snapshot, relIds, query) => evaluateBlocked(snapshot, relIds, query) },
  { name: 'risk_comparator', build: scenarioRiskComparator, eval: (snapshot, relIds, query) => evaluateRisk(snapshot, relIds, query) }
];

const args = parseArgs(process.argv);
const size = Number(args.get('size') || 50000);
const seed = Number(args.get('seed') || 1337);
const bucketSize = Number(args.get('bucket') || 65536);
const deltaPowers = String(args.get('delta-powers') || '0,1,2,3').split(',').map((v) => Number(v.trim()));
const compactAt = Number(args.get('compact-at') || 0);
const shardMode = String(args.get('shard-mode') || 'chain');
const componentRelations = args.get('component-relations')
  ? String(args.get('component-relations')).split(',').map((v) => v.trim()).filter(Boolean)
  : ['member', 'group_access', 'viewer', 'blocked', 'risk_score', 'risk_limit', 'owner'];
const chainGroupTargetSize = Number(args.get('chain-group-target-size') || 0);
const chainGroupTargetCount = Number(args.get('chain-group-target-count') || 0);

console.log('B2C delta overlay bench');
console.log(`  size: ${size}`);
console.log(`  bucket: ${bucketSize}`);
console.log(`  delta powers: ${deltaPowers.join(',')}`);
if (compactAt > 0) console.log(`  compact at: ${compactAt}`);
console.log(`  shard mode: ${shardMode}`);
console.log(`  component relations: ${componentRelations.join(',')}`);
console.log('  note: timings are per-query averages; expect noise and cache effects. Compare trends, not single points.');
if (chainGroupTargetSize > 0) console.log(`  chain group target size: ${chainGroupTargetSize}`);
if (chainGroupTargetCount > 0) console.log(`  chain group target count: ${chainGroupTargetCount}`);

for (const scenario of scenarios) {
  const rng = makeRng(seed + scenario.name.length);
  const { graph, queries, relations } = scenario.build(size, rng);
  graph.finalizePerfectHash();
  graph.finalizeWaveletAdjacency({ dropAdjacencyList: true });

  const dir = fs.mkdtempSync(path.join(os.tmpdir(), `b2c-delta-${scenario.name}-`));
  const { snapshot, manifest } = buildSnapshot(
    graph,
    bucketSize,
    dir,
    shardMode,
    componentRelations,
    chainGroupTargetSize > 0 ? chainGroupTargetSize : undefined,
    chainGroupTargetCount > 0 ? chainGroupTargetCount : undefined
  );
  const relIds = {};
  for (const rel of relations) {
    relIds[rel] = graph.getRelationId(rel);
  }
  const relationIds = relations.map((rel) => relIds[rel]);

  const baseBytes = sumShardBytes(dir, manifest);
  const shardFiles = countShardFiles(manifest);
  const shardStats = shardSizeStats(dir, manifest);

  console.log(`Scenario: ${scenario.name}`);
  console.log('deltaEdges | avg_us_per_query | base_bytes | shard_files | shard_p50 | shard_p95 | shard_p99 | delta_bytes | compact_ms | compact_us_per_edge');

  snapshot.setDeltaLayers([]);
  snapshot.clearDeltaCache();
  const baseline = timeQueries((query) => scenario.eval(snapshot, relIds, query), queries);
  console.log(`0 | ${(baseline.duration / queries.length) * 1000} | ${baseBytes} | ${shardFiles} | ${shardStats.p50} | ${shardStats.p95} | ${shardStats.p99} | 0 | - | -`);

  for (const power of deltaPowers) {
    const deltaEdges = Math.max(1, Math.floor(Math.pow(10, power)));
    const deltaDir = path.join(dir, `delta-${power}`);
    const layer = buildDeltaLayer(snapshot, relationIds, deltaEdges, rng, deltaDir);
    snapshot.setDeltaLayers([layer]);
    snapshot.clearDeltaCache();
    const result = timeQueries((query) => scenario.eval(snapshot, relIds, query), queries);
    const deltaBytes = sumDeltaBytes(deltaDir);
    let compactMs = '-';
    let compactUsPerEdge = '-';
    if (compactAt > 0 && deltaEdges >= compactAt) {
      const compactDir = path.join(dir, `compact-${scenario.name}-${power}`);
      const start = performance.now();
      for (const shardMeta of layer.shards) {
        const base = snapshot._cacheIndex.get(shardMeta.cacheKey);
        if (!base) continue;
        const shard = snapshot._loadShardSync(base.relationId, base.direction, base.rangeStart);
        if (!shard) continue;
        const deltaBuffer = layer.storage.getSync(shardMeta.key);
        if (!deltaBuffer) continue;
        const deltaShard = DeltaShardBinary.deserialize(deltaBuffer);
        const rangeSize = shard.rangeEnd - shard.rangeStart;
        const sources = new Array(rangeSize);
        for (let localSource = 0; localSource < rangeSize; localSource++) {
          const range = snapshot._rangeForSource(shard, localSource);
          const list = [];
          if (range) {
            for (let pos = range.start; pos < range.end; pos++) {
              list.push({ otherId: shard.dstIds[pos], possBits: shard.possBits[pos], relBits: shard.relBits[pos] });
            }
          }
          sources[localSource] = list;
        }
        for (const removal of deltaShard.removals) {
          const list = sources[removal.srcLocal];
          if (!list) continue;
          const idx = list.findIndex((item) => item.otherId === removal.otherId);
          if (idx !== -1) list.splice(idx, 1);
        }
        for (const addition of deltaShard.additions) {
          const list = sources[addition.srcLocal] || (sources[addition.srcLocal] = []);
          list.push({ otherId: addition.otherId, possBits: addition.possBits, relBits: addition.relBits });
        }
        const buffer = WaveletShardBinary.serialize({
          relationId: shard.relationId,
          direction: shard.direction,
          rangeStart: shard.rangeStart,
          rangeEnd: shard.rangeEnd,
          nodeCount: snapshot.nodeCount,
          sources
        });
        fs.mkdirSync(compactDir, { recursive: true });
        fs.writeFileSync(path.join(compactDir, base.key), new Uint8Array(buffer));
      }
      const totalMs = performance.now() - start;
      compactMs = totalMs.toFixed(2);
      const denom = Math.max(1, layer.addCount + layer.removeCount);
      compactUsPerEdge = ((totalMs * 1000) / denom).toFixed(3);
    }
    console.log(`${deltaEdges} | ${(result.duration / queries.length) * 1000} | ${baseBytes} | ${shardFiles} | ${shardStats.p50} | ${shardStats.p95} | ${shardStats.p99} | ${deltaBytes} | ${compactMs} | ${compactUsPerEdge}`);
  }

  fs.rmSync(dir, { recursive: true, force: true });
}