import { test } from "node:test";
import assert from "node:assert/strict";
import fs from "node:fs";
import path from "node:path";
import { RunsError, readActivationLog, readActivePointer } from "../src/index.mjs";
import { scratch, tree, write } from "./helpers.mjs";

const POINTER = { pointerVersion: 1, release: "0.0.12", imageTag: "mosaic-poc-agent:0.84.4-r0.0.12", activatedAt: "2026-09-03T20:58:15Z" };

function entry(at, event, release, extra = {}) {
  return { at, event, release, imageTag: `mosaic-poc-agent:0.84.4-r${release}`, ...extra };
}

function writeLog(dataRoot, lines) {
  write(path.join(dataRoot, "state", "activation-log.jsonl"), lines.map((l) => (typeof l === "string" ? l : JSON.stringify(l))).join("\n") + "\n");
}

test("no pointer is null", (t) => {
  const { dir, dataRoot } = scratch(t);
  assert.equal(readActivePointer(dataRoot), null);
  assert.equal(readActivePointer(path.join(dir, "absent")), null);
});

test("the pointer release.sh writes reads back", (t) => {
  const { dataRoot } = scratch(t);
  // The exact bytes of release.sh's printf.
  write(path.join(dataRoot, "state", "active.json"),
    '{"pointerVersion":1,"release":"0.0.12","imageTag":"mosaic-poc-agent:0.84.4-r0.0.12","activatedAt":"2026-09-03T20:58:15Z"}\n');
  assert.deepEqual(readActivePointer(dataRoot), POINTER);
});

test("a pointer that isn't the version 1 shape refuses with exit 2", (t) => {
  const { dataRoot } = scratch(t);
  const file = path.join(dataRoot, "state", "active.json");
  const cases = [
    ["{ truncated", /not valid JSON/],
    ["[]", /must be a JSON object/],
    ["null", /must be a JSON object/],
    [{ ...POINTER, extra: 1 }, /unsupported key: "extra"/],
    [{ ...POINTER, pointerVersion: 2 }, /unsupported pointerVersion 2/],
    [{ ...POINTER, release: "" }, /non-empty string "release"/],
    [{ ...POINTER, imageTag: 5 }, /non-empty string "imageTag"/],
    [{ pointerVersion: 1, release: "0.0.1", imageTag: "x" }, /non-empty string "activatedAt"/],
  ];
  for (const [content, pattern] of cases) {
    write(file, content);
    assert.throws(() => readActivePointer(dataRoot), (e) => e instanceof RunsError && e.exitCode === 2 && pattern.test(e.message), String(pattern));
  }
});

test("a pointer that is a directory refuses with exit 4", (t) => {
  const { dataRoot } = scratch(t);
  fs.mkdirSync(path.join(dataRoot, "state", "active.json"), { recursive: true });
  assert.throws(() => readActivePointer(dataRoot), (e) => e instanceof RunsError && e.exitCode === 4 && /EISDIR/.test(e.message));
});

test("a state file linked out of the data root refuses", (t) => {
  const { dataRoot, outside } = scratch(t);
  write(path.join(outside, "active.json"), POINTER);
  write(path.join(outside, "log.jsonl"), `${JSON.stringify(entry("a", "activate", "0.0.1"))}\n`);
  fs.mkdirSync(path.join(dataRoot, "state"));
  fs.symlinkSync(path.join(outside, "active.json"), path.join(dataRoot, "state", "active.json"));
  fs.symlinkSync(path.join(outside, "log.jsonl"), path.join(dataRoot, "state", "activation-log.jsonl"));
  assert.throws(() => readActivePointer(dataRoot), /resolves outside the data root/);
  assert.throws(() => readActivationLog(dataRoot), /resolves outside the data root/);
});

test("a state directory linked out of the data root refuses", (t) => {
  const { dataRoot, outside } = scratch(t);
  write(path.join(outside, "active.json"), POINTER);
  fs.symlinkSync(outside, path.join(dataRoot, "state"));
  assert.throws(() => readActivePointer(dataRoot), /state\/active.json resolves outside the data root/);
});

test("a state directory linked out to nothing reads as no release and an empty log", (t) => {
  const { dataRoot, outside } = scratch(t);
  fs.symlinkSync(path.join(outside, "absent"), path.join(dataRoot, "state"));
  assert.equal(readActivePointer(dataRoot), null);
  assert.deepEqual(readActivationLog(dataRoot), { entries: [], malformed: 0 });
});

test("a missing log is empty", (t) => {
  const { dataRoot } = scratch(t);
  assert.deepEqual(readActivationLog(dataRoot), { entries: [], malformed: 0 });
});

test("the log reads oldest first and counts malformed lines", (t) => {
  const { dataRoot } = scratch(t);
  const good = [
    entry("2026-09-03T20:57:00Z", "package", "0.0.12"),
    entry("2026-09-03T20:57:47Z", "activate", "0.0.12"),
    entry("2026-09-03T20:57:50Z", "refused", "0.0.11", { note: "health check failed (fault-injected)" }),
    entry("2026-09-03T20:58:15Z", "rollback", "0.0.11"),
  ];
  writeLog(dataRoot, [
    good[0],
    "{ torn line",
    good[1],
    "",
    "   ",
    "[]",
    { ...good[1], extra: true },
    { ...good[1], at: 5 },
    { ...good[1], note: null },
    { at: good[1].at, event: good[1].event, release: good[1].release },
    { ...good[1], release: 5 },
    good[2],
    good[3],
  ]);
  assert.deepEqual(readActivationLog(dataRoot), { entries: good, malformed: 7 });
  assert.deepEqual(readActivationLog(dataRoot, { last: 2 }), { entries: good.slice(2), malformed: 7 });
  assert.deepEqual(readActivationLog(dataRoot, { last: 99 }).entries, good);
});

test("last must be a positive integer", (t) => {
  const { dataRoot } = scratch(t);
  for (const last of [0, -1, 1.5, "2", null]) {
    assert.throws(() => readActivationLog(dataRoot, { last }), /last must be a positive integer/, String(last));
  }
});

test("the state readers write nothing", (t) => {
  const { dataRoot } = scratch(t);
  write(path.join(dataRoot, "state", "active.json"), POINTER);
  writeLog(dataRoot, [entry("a", "activate", "0.0.1"), "{ bad"]);
  const before = tree(dataRoot);
  readActivePointer(dataRoot);
  readActivationLog(dataRoot);
  readActivationLog(dataRoot, { last: 1 });
  assert.equal(tree(dataRoot), before);
});