import { describe, test } from "node:test";
import assert from "node:assert/strict";

import { proposeDiff, applyDiff, type Candidate } from "../src/consolidate.js";
import { mintEntityId } from "../src/id.js";
import { parseProfile, serializeProfile } from "../src/profile.js";
import type { ProfileDoc, ProfileFact } from "../src/types.js";

const TODAY = "2026-06-23";
const observedId = (key: string) => mintEntityId({ kind: "observed", key });

const fact = (over: Partial<ProfileFact>): ProfileFact => ({
  id: "000000000000",
  value: "v",
  first_seen: "2026-01-01",
  last_seen: TODAY,
  evidence_count: 1,
  provenance: "published",
  status: "active",
  ...over,
});
const doc = (staticF: ProfileFact[], dynamicF: ProfileFact[]): ProfileDoc => ({
  schemaVersion: 1,
  static: staticF,
  dynamic: dynamicF,
});
const cand = (over: Partial<Candidate>): Candidate => ({
  key: "k",
  value: "v",
  provenance: "published",
  source: "manual",
  observed_date: TODAY,
  ...over,
});

describe("proposeDiff classification (SC1a–g)", () => {
  test("SC1a — add: a published candidate with no match becomes a new dynamic fact", () => {
    const diff = proposeDiff({ current: doc([], []), candidates: [cand({ key: "topic", value: "AI safety" })], today: TODAY });
    assert.equal(diff.additions.length, 1);
    assert.equal(diff.additions[0].value, "AI safety");
    assert.equal(diff.additions[0].id, observedId("topic"));
    assert.equal(diff.additions[0].evidence_count, 1);
    assert.equal(diff.additions[0].status, "active");
  });

  test("SC1b — reject: an ai-draft candidate produces an empty diff", () => {
    const diff = proposeDiff({ current: doc([], []), candidates: [cand({ provenance: "ai-draft" })], today: TODAY });
    assert.deepEqual(diff.additions, []);
    assert.deepEqual(diff.evidenceBumps, []);
    assert.deepEqual(diff.promotions, []);
    assert.deepEqual(diff.conflicts, []);
  });

  test("SC1c — evidence-bump: same key+value bumps the existing fact, no addition", () => {
    const id = observedId("topic");
    const cur = doc([], [fact({ id, value: "AI safety", evidence_count: 1 })]);
    const diff = proposeDiff({ current: cur, candidates: [cand({ key: "topic", value: "AI safety" })], today: TODAY });
    assert.equal(diff.additions.length, 0);
    assert.equal(diff.evidenceBumps.length, 1);
    assert.deepEqual(diff.evidenceBumps[0], { id, newCount: 2, last_seen: TODAY });
  });

  test("SC1d — promote: a dynamic fact reaching N=3 is promoted", () => {
    const id = observedId("topic");
    const cur = doc([], [fact({ id, value: "AI safety", evidence_count: 2 })]);
    const diff = proposeDiff({ current: cur, candidates: [cand({ key: "topic", value: "AI safety" })], today: TODAY });
    assert.equal(diff.evidenceBumps[0].newCount, 3);
    assert.deepEqual(diff.promotions, [{ id }]);
  });

  test("SC1d — no promote below N", () => {
    const id = observedId("topic");
    const cur = doc([], [fact({ id, value: "x", evidence_count: 1 })]);
    const diff = proposeDiff({ current: cur, candidates: [cand({ key: "topic", value: "x" })], today: TODAY });
    assert.deepEqual(diff.promotions, []);
  });

  test("SC1e — conflict: different value keeps BOTH with DISTINCT ids, old fact untouched", () => {
    const primaryId = observedId("role");
    const cur = doc([], [fact({ id: primaryId, value: "advisor", evidence_count: 2 })]);
    const diff = proposeDiff({ current: cur, candidates: [cand({ key: "role", value: "architect" })], today: TODAY });
    assert.equal(diff.conflicts.length, 1);
    assert.equal(diff.conflicts[0].primaryId, primaryId);
    assert.equal(diff.conflicts[0].primaryValue, "advisor");
    assert.notEqual(diff.conflicts[0].altId, primaryId, "alt id must differ from primary id (no duplicate-id corruption)");
    // the alt fact is added; the old fact is NOT bumped
    assert.equal(diff.additions.length, 1);
    assert.equal(diff.additions[0].value, "architect");
    assert.equal(diff.additions[0].id, diff.conflicts[0].altId);
    assert.deepEqual(diff.evidenceBumps, []);
  });

  test("SC1f — decay: a dynamic fact older than 90d is flagged; a static fact is decay-exempt", () => {
    const old = "2026-03-01"; // ~114 days before TODAY
    const dyn = fact({ id: observedId("stale-topic"), value: "old", last_seen: old });
    const stat = fact({ id: observedId("settled"), value: "stable", last_seen: old });
    const cur = doc([stat], [dyn]);
    const diff = proposeDiff({ current: cur, candidates: [], today: TODAY });
    assert.equal(diff.staleFlags.length, 1, "only the dynamic stale fact is flagged");
    assert.equal(diff.staleFlags[0].id, dyn.id);
    assert.ok(diff.staleFlags[0].daysStale > 90);
  });

  test("SC1f — a fresh dynamic fact is not flagged", () => {
    const cur = doc([], [fact({ id: observedId("fresh"), last_seen: "2026-06-20" })]);
    const diff = proposeDiff({ current: cur, candidates: [], today: TODAY });
    assert.deepEqual(diff.staleFlags, []);
  });

  test("SC1g — folded immutable: a candidate overlapping a profile-field seed adds a new observed fact, seed untouched", () => {
    const foldedId = mintEntityId({ kind: "profile-field", key: "role" });
    const folded = fact({ id: foldedId, value: "advisor", provenance: "human" });
    const cur = doc([folded], []);
    const before = serializeProfile(cur);
    const diff = proposeDiff({ current: cur, candidates: [cand({ key: "role", value: "architect" })], today: TODAY });
    // candidate keys to observed:role (≠ profile-field:role) → no match → ADD, no conflict on the folded seed
    assert.equal(diff.additions.length, 1);
    assert.equal(diff.additions[0].id, observedId("role"));
    assert.equal(diff.conflicts.length, 0);
    assert.equal(serializeProfile(cur), before, "input doc not mutated; folded seed untouched");
  });
});

describe("proposeDiff purity + applyDiff round-trip (SC2, SC3, SC4)", () => {
  test("SC2 — proposeDiff does not mutate its inputs", () => {
    const cur = doc([], [fact({ id: observedId("topic"), value: "x" })]);
    const candidates = [cand({ key: "topic", value: "x" }), cand({ key: "new", value: "y" })];
    const snapCur = JSON.stringify(cur);
    const snapCand = JSON.stringify(candidates);
    proposeDiff({ current: cur, candidates, today: TODAY });
    assert.equal(JSON.stringify(cur), snapCur, "current unchanged");
    assert.equal(JSON.stringify(candidates), snapCand, "candidates unchanged");
  });

  test("SC3 — applyDiff(current, proposeDiff(...)) round-trips through parse/serialize", () => {
    const cur = doc([fact({ id: mintEntityId({ kind: "profile-field", key: "name" }), value: "KTG", provenance: "human" })], [fact({ id: observedId("topic"), value: "AI safety", evidence_count: 2 })]);
    const candidates = [
      cand({ key: "topic", value: "AI safety" }), // bump→promote
      cand({ key: "new-topic", value: "governance" }), // add
      cand({ key: "topic", value: "alignment" }), // conflict on topic → alt
    ];
    const diff = proposeDiff({ current: cur, candidates, today: TODAY });
    const next = applyDiff(cur, diff);
    const round = parseProfile(serializeProfile(next));
    assert.deepEqual(round, next, "applied doc round-trips exactly");
    // every fact id is unique (no duplicate-id corruption)
    const ids = [...round.static, ...round.dynamic].map((f) => f.id);
    assert.equal(new Set(ids).size, ids.length, "all fact ids unique");
  });

  test("SC4 — idempotent: re-running propose→apply with the same candidates adds no duplicate facts", () => {
    const cur = doc([], []);
    const candidates = [cand({ key: "topic", value: "AI safety" })];
    const once = applyDiff(cur, proposeDiff({ current: cur, candidates, today: TODAY }));
    const twice = applyDiff(once, proposeDiff({ current: once, candidates, today: TODAY }));
    const factsOnce = [...once.static, ...once.dynamic].length;
    const factsTwice = [...twice.static, ...twice.dynamic].length;
    assert.equal(factsTwice, factsOnce, "no duplicate fact on re-run (bump only)");
  });
});