import assert from "node:assert/strict";
import { execFileSync } from "node:child_process";
import { existsSync, readFileSync, writeFileSync } from "node:fs";
import path from "node:path";
import { fileURLToPath } from "node:url";
import { stripVTControlCharacters } from "node:util";
import { listE2eSpecs } from "../e2e-shard.mjs";
import { ghApi } from "./gh-api.mjs";
import { oversizedThresholdEnv, oversizedThresholdMs } from "./oversized-test-files.mjs";
import { collectMergedPrSamples, e2eManifest, e2eShardJob, isMergedIntoHead, parseE2eLog, parseRunnerLog,
  runnerInventory, runnerManifest, runnerPackageJob } from "./pr-run-durations.mjs";
import { timingPrefix } from "./test-timing-reporter.mjs";

const repository = "paperclipai/paperclip";
const api = `/repos/${repository}`;
const github = (endpoint, json = true) => ghApi(endpoint, { json });
const masterComment = "Generated by node scripts/ci/refresh-test-durations.mjs from successful protected-master Cloud readiness runs. Median per-file cost includes tests, hooks, collection, setup and environment preparation when the timing reporter is present; older logs bootstrap test/hook durations only. Missing files retain their prior weight or the partitioner's median fallback. Timing changes only partition work; they never authorize skipping a test.";
const e2eComment = "Generated by node scripts/ci/refresh-test-durations.mjs from successful .github/workflows/pr.yml runs of PRs merged into master, each pinned to the PR's final head SHA. Per spec: the sum of gaps between consecutive Playwright result lines in 'Run e2e tests' (one worker), so fixture and navigation time count; tests located in a *.shared.ts file are attributed to the shard's matching spec. Median across runs. scripts/e2e-shard.mjs uses these weights only to place specs on shards; they never change which specs run. Missing specs retain their prior weight or the median fallback.";
const runnerComment = "Generated by node scripts/ci/refresh-test-durations.mjs from successful .github/workflows/pr.yml runs of PRs merged into master, each pinned to the PR's final head SHA. Per file: the Vitest file duration printed by the Verify Paperclip Runner package job (tests and hooks; collection and setup are not included). Median across runs. Weights only place files on lanes; they never change which tests run. Missing files retain their prior weight or the median fallback.";

export function validateRun(run) {
  assert.equal(run.repository?.full_name, repository);
  assert.equal(run.repository?.id, 1170821064);
  assert.equal(run.head_repository?.id, 1170821064);
  assert.equal(run.head_branch, "master");
  assert.equal(run.event, "push");
  assert.equal(run.path, ".github/workflows/cloud-readiness.yml");
  assert.equal(run.status, "completed");
  assert.equal(run.conclusion, "success");
  assert.match(run.head_sha, /^[a-f0-9]{40}$/);
  assert.ok(Number.isSafeInteger(run.id) && run.id > 0);
  assert.ok(Number.isSafeInteger(run.run_attempt) && run.run_attempt > 0);
}

export function parseTimings(log, inventory) {
  const fallback = new Map(), measured = new Map();
  for (const raw of log.split("\n")) {
    const line = stripVTControlCharacters(raw);
    const offset = line.indexOf(timingPrefix);
    if (offset >= 0) {
      const record = JSON.parse(line.slice(offset + timingPrefix.length));
      assert.equal(record.version, 1);
      assert.equal(typeof record.file, "string");
      assert.match(record.file, /^server\/(src|scripts)\/.+\.test\.[cm]?[jt]s$/);
      assert.ok(!record.file.split("/").some(part => part === ".." || part === "." || part === ""));
      assert.ok(!record.file.includes("\\"));
      assert.ok(Number.isFinite(record.durationMs) && record.durationMs >= 0 && record.durationMs <= 3_600_000);
      // A trusted source run can predate a deletion or a lane reassignment.
      if (!inventory.has(record.file)) continue;
      measured.set(record.file, Math.max(measured.get(record.file) ?? 0, record.durationMs));
      continue;
    }
    // Bootstrap from pre-reporter runs. These values omit import/setup cost;
    // structured measurements take precedence as soon as master emits them.
    const match = line.match(/@paperclipai\/server\s+([^\s]+\.test\.[cm]?[jt]s)\s+\(\d+ tests?[^)]*\)\s+(\d+)ms\s*$/);
    if (!match) continue;
    const file = `server/${match[1]}`, ms = Number(match[2]);
    if (inventory.has(file) && ms <= 3_600_000) fallback.set(file, Math.max(fallback.get(file) ?? 0, ms));
  }
  return new Map([...fallback].map(([file, ms]) => [file, { ms, complete: false }])
    .concat([...measured].map(([file, ms]) => [file, { ms, complete: true }])));
}

export function updatedDurations(previous, inventory, samples, sources, { comment = masterComment } = {}) {
  const measured = [...inventory].filter(file => samples.some(sample => sample.has(file)));
  assert.ok(measured.length >= inventory.size * 0.9, `Incomplete timing coverage: ${measured.length}/${inventory.size}`);
  const durations = {};
  let complete = 0;
  for (const file of [...inventory].sort()) {
    const values = samples.flatMap(sample => sample.has(file) ? [sample.get(file)] : []);
    const full = values.filter(value => value.complete);
    if (full.length) complete++;
    const ms = (full.length ? full : values).map(value => value.ms).sort((a, b) => a - b);
    if (!ms.length) {
      if (Number.isFinite(previous.durations[file]) && previous.durations[file] >= 0) durations[file] = previous.durations[file];
      continue;
    }
    const middle = Math.floor(ms.length / 2);
    // A small floor prevents clock resolution from giving a suite zero cost.
    durations[file] = Math.max(100, Math.ceil(ms.length % 2 ? ms[middle] : (ms[middle - 1] + ms[middle]) / 2));
  }
  return {
    $comment: comment,
    unit: "ms", sources, coverage: { measured: measured.length, withSetup: complete, inventory: inventory.size }, durations,
  };
}

// Files over the per-file budget, slowest first, across every refreshed manifest.
export function oversizedFiles(manifests, thresholdMs) {
  return manifests.flatMap(({ data }) => Object.entries(data.durations))
    .filter(([, ms]) => ms > thresholdMs).sort((a, b) => b[1] - a[1] || a[0].localeCompare(b[0]));
}

export const oversizedPlaceholder = "<!-- oversized-test-files -->";

export function renderPrBody(template, oversized, thresholdMs) {
  assert.ok(template.includes(oversizedPlaceholder), "PR body template lacks the oversized-file placeholder");
  const seconds = Math.round(thresholdMs / 1000);
  const lines = oversized.length
    ? [`- ${oversized.length} test file(s) exceed the ${seconds}s per-file budget (\`${oversizedThresholdEnv}\`). A shard cannot split a file, so each one bounds its lane's wall-clock time. Consider splitting:`,
      ...oversized.map(([file, ms]) => `  - \`${file}\`: ${Math.round(ms / 1000)}s`)]
    : [`- No measured test file exceeds the ${seconds}s per-file budget (\`${oversizedThresholdEnv}\`).`];
  return template.replace(oversizedPlaceholder, lines.join("\n"));
}

function summarizeChange(file, previous, next) {
  const before = previous?.durations ?? {}, after = next.durations;
  const changes = Object.keys(after).map(key => [key, before[key], after[key]])
    .filter(([, old, value]) => old !== value)
    .sort((a, b) => Math.abs(b[2] - (b[1] ?? 0)) - Math.abs(a[2] - (a[1] ?? 0)));
  const removed = Object.keys(before).filter(key => !(key in after));
  console.log(`${file}: ${next.coverage.measured}/${next.coverage.inventory} measured; ${next.coverage.withSetup} include setup; `
    + `${changes.length} changed, ${removed.length} removed; sources ${next.sources.map(source => source.pull ? `#${source.pull}/${source.run}` : source.run).join(", ")}`);
  for (const [key, old, value] of changes.slice(0, 12)) console.log(`  ${key}: ${old ?? "(new)"} -> ${value}`);
}

export function parseArgs(argv) {
  const options = { runIds: [], dryRun: false, prBody: null, lanes: new Set(["server", "e2e", "runner"]) };
  for (const arg of argv) {
    if (arg === "--dry-run") options.dryRun = true;
    else if (arg.startsWith("--pr-body=")) options.prBody = arg.slice("--pr-body=".length);
    else if (arg.startsWith("--lanes=")) {
      options.lanes = new Set(arg.slice("--lanes=".length).split(","));
      for (const lane of options.lanes) assert.ok(["server", "e2e", "runner"].includes(lane), `Unknown lane ${lane}`);
    } else {
      assert.match(arg, /^\d+$/, `Unexpected argument ${arg}`);
      options.runIds.push(arg);
    }
  }
  return options;
}

export const serverLane = name => /General tests \(server \(\d+\/\d+\)\)$/.test(name) ? "general"
  : /Serialized tests \(\d+\/\d+\)$/.test(name) ? "serialized" : null;

const readManifest = file => existsSync(file) ? JSON.parse(readFileSync(file, "utf8")) : { durations: {} };

async function refreshMasterLanes(runIds) {
  const inventory = JSON.parse(execFileSync(process.execPath, ["scripts/run-vitest-stable.mjs", "--mode", "general",
    "--group", "general-server", "--shard-index", "0", "--shard-count", "1", "--dry-run"], {
    encoding: "utf8", env: { ...process.env, GITHUB_WORKFLOW: "PR", PAPERCLIP_CI_TEST_SELECTION: "" },
  }));
  const lanes = {
    general: { files: new Set(inventory.selectedGeneralServerSuites), path: "scripts/general-server-shard-durations.json", samples: [] },
    serialized: { files: new Set(inventory.selectedSerializedSuites), path: "scripts/serialized-shard-durations.json", samples: [] },
  };
  const runJobs = async run => {
    const jobs = [];
    for (let page = 1; ; page++) {
      const result = await github(`${api}/actions/runs/${run.id}/attempts/${run.run_attempt}/jobs?per_page=100&page=${page}`);
      jobs.push(...result.jobs);
      if (result.jobs.length < 100) break;
    }
    return jobs;
  };
  const candidates = [];
  if (runIds.length) {
    assert.ok(runIds.length <= 3, "Expected one to three successful master runs");
    for (const id of runIds) {
      assert.match(String(id), /^\d+$/);
      const run = await github(`${api}/actions/runs/${id}`);
      validateRun(run);
      execFileSync("git", ["merge-base", "--is-ancestor", run.head_sha, "HEAD"]);
      candidates.push({ run, jobs: await runJobs(run) });
    }
  } else {
    // Most master pushes only run Cloud admission and skip verification, and a
    // newer push can land after this checkout. Use the two newest runs this
    // checkout contains that actually ran the server test jobs.
    const listed = await github(`${api}/actions/workflows/cloud-readiness.yml/runs?branch=master&event=push&status=success&per_page=50`);
    for (const run of listed.workflow_runs) {
      if (candidates.length === 2) break;
      if (!isMergedIntoHead(run.head_sha)) continue;
      validateRun(run);
      const jobs = await runJobs(run);
      if (jobs.some(job => serverLane(job.name))) candidates.push({ run, jobs });
    }
  }
  assert.ok(candidates.length > 0, "Expected one to three successful master runs");
  const sources = [];
  for (const { run, jobs } of candidates) {
    const samples = { general: new Map(), serialized: new Map() };
    const selected = jobs.map(job => ({ job, lane: serverLane(job.name) })).filter(item => item.lane);
    assert.ok(selected.length, "No server timing jobs found");
    // Keep API traffic and log buffers bounded. Logs are parsed data, never code.
    for (let start = 0; start < selected.length; start += 3) {
      await Promise.all(selected.slice(start, start + 3).map(async ({ job, lane }) => {
        assert.equal(job.run_id, run.id);
        assert.equal(job.conclusion, "success");
        const parsed = parseTimings(await github(`${api}/actions/jobs/${job.id}/logs`, false), lanes[lane].files);
        for (const [file, value] of parsed) {
          const previous = samples[lane].get(file);
          if (!previous || (value.complete && !previous.complete)
            || (value.complete === previous.complete && value.ms > previous.ms)) samples[lane].set(file, value);
        }
      }));
    }
    for (const lane of Object.keys(lanes)) lanes[lane].samples.push(samples[lane]);
    sources.push({ run: run.id, attempt: run.run_attempt, sha: run.head_sha, url: run.html_url });
  }
  return Object.values(lanes).map(lane => {
    const previous = readManifest(lane.path);
    return { path: lane.path, previous, data: updatedDurations(previous, lane.files, lane.samples, sources) };
  });
}

// Fewer than two valid runs leaves a manifest unchanged with a visible warning;
// one run is too noisy to replace measured weights.
async function refreshPrLanes(names) {
  if (!names.length) return [];
  const definitions = {
    e2e: () => ({ classify: e2eShardJob, parse: parseE2eLog, inventory: new Set(listE2eSpecs()), path: e2eManifest, comment: e2eComment }),
    runner: () => ({ classify: runnerPackageJob, parse: parseRunnerLog, inventory: runnerInventory(), path: runnerManifest, comment: runnerComment }),
  };
  const lanes = names.map(name => ({ name, ...definitions[name]() }));
  const collected = await collectMergedPrSamples({ gh: github, lanes });
  const updates = [];
  for (const lane of lanes) {
    const { samples, sources } = collected[lane.name];
    if (samples.length < 2) {
      console.log(`::warning::${lane.path}: only ${samples.length} valid merged-PR run(s); keeping the current weights`);
      continue;
    }
    const previous = readManifest(lane.path);
    updates.push({ path: lane.path, previous,
      data: updatedDurations(previous, lane.inventory, samples, sources, { comment: lane.comment }) });
  }
  return updates;
}

export async function refreshDurations(argv = []) {
  const options = parseArgs(argv.map(String));
  const updates = [
    ...(options.lanes.has("server") ? await refreshMasterLanes(options.runIds) : []),
    ...await refreshPrLanes(["e2e", "runner"].filter(lane => options.lanes.has(lane))),
  ];
  // Validate every lane before replacing any checked-in manifest.
  for (const { path: file, previous, data } of updates) {
    summarizeChange(file, previous, data);
    if (!options.dryRun) writeFileSync(file, JSON.stringify(data, null, 2) + "\n");
  }
  const thresholdMs = oversizedThresholdMs();
  const oversized = oversizedFiles(updates, thresholdMs);
  console.log(`${oversized.length} measured test file(s) exceed ${Math.round(thresholdMs / 1000)}s`);
  for (const [file, ms] of oversized) console.log(`  ${file}: ${Math.round(ms / 1000)}s`);
  if (options.prBody) {
    writeFileSync(options.prBody, renderPrBody(readFileSync(".github/ci-duration-pr.md", "utf8"), oversized, thresholdMs));
  }
  if (options.dryRun) console.log("Dry run: no manifest was written");
  return updates;
}

if (process.argv[1] && path.resolve(process.argv[1]) === fileURLToPath(import.meta.url)) {
  refreshDurations(process.argv.slice(2)).catch(error => { console.error(error); process.exitCode = 1; });
}