import { spawn } from "node:child_process";
import { performance } from "node:perf_hooks";
import {
  detectChangedLanes,
  listChangedPathsFromGit,
  listStagedChangedPaths,
  normalizeChangedPath,
} from "./changed-lanes.mjs";

const ROUTABLE_TEST_PATH_RE = /^(?:src|test|extensions|ui|packages|apps)(?:\/|$)/u;

export function createChangedCheckPlan(result) {
  const commands = [];
  const add = (name, args) => {
    if (!commands.some((command) => command.name === name && sameArgs(command.args, args))) {
      commands.push({ name, args });
    }
  };

  add("conflict markers", ["check:no-conflict-markers"]);

  if (result.docsOnly) {
    return {
      commands,
      testTargets: [],
      runFullTests: false,
      runExtensionTests: false,
      summary: "docs-only",
    };
  }

  const lanes = result.lanes;
  const runAll = lanes.all;

  if (runAll) {
    add("typecheck all", ["tsgo:all"]);
    add("lint", ["lint"]);
    add("runtime import cycles", ["check:import-cycles"]);
    return {
      commands,
      testTargets: [],
      runFullTests: true,
      runExtensionTests: false,
      summary: "all",
    };
  }

  if (lanes.core) {
    add("typecheck core", ["tsgo:core"]);
  }
  if (lanes.coreTests) {
    add("typecheck core tests", ["tsgo:core:test"]);
  }
  if (lanes.extensions) {
    add("typecheck extensions", ["tsgo:extensions"]);
  }
  if (lanes.extensionTests) {
    add("typecheck extension tests", ["tsgo:extensions:test"]);
  }

  if (lanes.core || lanes.coreTests) {
    add("lint core", ["lint:core"]);
  }
  if (lanes.extensions || lanes.extensionTests) {
    add("lint extensions", ["lint:extensions"]);
  }
  if (lanes.tooling) {
    add("lint scripts", ["lint:scripts"]);
  }
  if (lanes.apps) {
    add("lint apps", ["lint:apps"]);
  }

  if (lanes.core || lanes.extensions) {
    add("runtime import cycles", ["check:import-cycles"]);
  }
  if (lanes.core) {
    add("webhook body guard", ["lint:webhook:no-low-level-body-read"]);
    add("pairing store guard", ["lint:auth:no-pairing-store-group"]);
    add("pairing account guard", ["lint:auth:pairing-account-scope"]);
  }

  const testTargets = result.paths.filter((changedPath) => ROUTABLE_TEST_PATH_RE.test(changedPath));
  return {
    commands,
    testTargets,
    runFullTests: false,
    runExtensionTests: result.extensionImpactFromCore,
    summary: Object.entries(lanes)
      .filter(([, enabled]) => enabled)
      .map(([lane]) => lane)
      .join(", "),
  };
}

export async function runChangedCheck(result, options = {}) {
  const plan = createChangedCheckPlan(result);
  printPlan(result, plan, options);

  if (options.dryRun) {
    return 0;
  }

  const timings = [];
  for (const command of plan.commands) {
    const status = await runPnpm(command, timings);
    if (status !== 0) {
      printSummary(timings, options);
      return status;
    }
  }

  if (plan.runFullTests) {
    const status = await runPnpm({ name: "tests all", args: ["test"] }, timings);
    if (status !== 0) {
      printSummary(timings, options);
      return status;
    }
  } else if (plan.testTargets.length > 0) {
    const status = await runNode(
      {
        name: "tests changed",
        args: ["scripts/test-projects.mjs", ...plan.testTargets],
      },
      timings,
    );
    if (status !== 0) {
      printSummary(timings, options);
      return status;
    }
  }

  if (plan.runExtensionTests) {
    const status = await runPnpm({ name: "tests extensions", args: ["test:extensions"] }, timings);
    if (status !== 0) {
      printSummary(timings, options);
      return status;
    }
  }

  printSummary(timings, options);
  return 0;
}

function sameArgs(left, right) {
  return left.length === right.length && left.every((value, index) => value === right[index]);
}

function printPlan(result, plan, options) {
  const prefix = options.dryRun ? "[check:changed:dry-run]" : "[check:changed]";
  console.error(`${prefix} lanes=${plan.summary || "none"}`);
  if (result.extensionImpactFromCore) {
    console.error(`${prefix} core contract changed; extension tests included`);
  }
  for (const reason of result.reasons) {
    console.error(`${prefix} ${reason}`);
  }
  if (plan.testTargets.length > 0) {
    console.error(`${prefix} test targets=${plan.testTargets.length}`);
  }
}

async function runPnpm(command, timings) {
  return await runCommand({ ...command, bin: "pnpm" }, timings);
}

async function runNode(command, timings) {
  return await runCommand({ ...command, bin: process.execPath }, timings);
}

async function runCommand(command, timings) {
  const startedAt = performance.now();
  console.error(`\n[check:changed] ${command.name}`);
  const child = spawn(command.bin, command.args, {
    stdio: "inherit",
    shell: process.platform === "win32",
  });

  return await new Promise((resolve) => {
    child.once("error", (error) => {
      console.error(error);
      timings.push({
        name: command.name,
        durationMs: performance.now() - startedAt,
        status: 1,
      });
      resolve(1);
    });
    child.once("close", (status) => {
      const resolvedStatus = status ?? 1;
      timings.push({
        name: command.name,
        durationMs: performance.now() - startedAt,
        status: resolvedStatus,
      });
      resolve(resolvedStatus);
    });
  });
}

function printSummary(timings, options) {
  if (!options.timed && timings.every((timing) => timing.status === 0)) {
    return;
  }
  console.error("\n[check:changed] summary");
  for (const timing of timings) {
    const status = timing.status === 0 ? "ok" : `failed:${timing.status}`;
    console.error(
      `${formatMs(timing.durationMs).padStart(8)}  ${status.padEnd(9)}  ${timing.name}`,
    );
  }
}

function formatMs(durationMs) {
  if (durationMs < 1000) {
    return `${Math.round(durationMs)}ms`;
  }
  return `${(durationMs / 1000).toFixed(2)}s`;
}

function parseArgs(argv) {
  const args = {
    base: "origin/main",
    head: "HEAD",
    staged: false,
    dryRun: false,
    timed: false,
    paths: [],
  };
  for (let index = 0; index < argv.length; index += 1) {
    const arg = argv[index];
    if (arg === "--base") {
      args.base = argv[index + 1] ?? args.base;
      index += 1;
      continue;
    }
    if (arg === "--head") {
      args.head = argv[index + 1] ?? args.head;
      index += 1;
      continue;
    }
    if (arg === "--staged") {
      args.staged = true;
      continue;
    }
    if (arg === "--dry-run") {
      args.dryRun = true;
      continue;
    }
    if (arg === "--timed") {
      args.timed = true;
      continue;
    }
    args.paths.push(normalizeChangedPath(arg));
  }
  return args;
}

function isDirectRun() {
  const direct = process.argv[1];
  return Boolean(direct && import.meta.url.endsWith(direct));
}

if (isDirectRun()) {
  const args = parseArgs(process.argv.slice(2));
  const paths =
    args.paths.length > 0
      ? args.paths
      : args.staged
        ? listStagedChangedPaths()
        : listChangedPathsFromGit({ base: args.base, head: args.head });
  const result = detectChangedLanes(paths);
  process.exitCode = await runChangedCheck(result, args);
}