/**
 * RTO.26B — Branch-scoped experimental fixture
 *
 * Replicates the RTO.26A branch record inside the UI layer.
 * Membership is determined by explicit `branchId` provenance only.
 *
 * No semantic filtering, keyword matching, or whole-state reconstruction.
 */

// ── Deterministic ID generator (mirrors RTO.26A harness) ───────────────

function genId(prefix, label) {
  let h = 0;
  for (let i = 0; i < label.length; i++) {
    h = (Math.imul(31, h) + label.charCodeAt(i)) | 0;
  }
  return `${prefix}-${(Math.abs(h) % 1e6).toString(16).padStart(6, "0")}`;
}

// ── Record model (explicit provenance via `branchId`) ─────────────────

function createQuestion(branchId, text) {
  return {
    id: genId("question", text.slice(0, 20)),
    branchId,
    text,
    contributions: [], // stores contribution ids
  };
}

function createContribution(branchId, questionId, text) {
  return {
    id: genId("contribution", text.slice(0, 20)),
    branchId,
    questionId,
    text,
  };
}

function createLateResult(branchId, contributionId, text) {
  return {
    id: genId("late-result", text.slice(0, 20)),
    branchId,
    contributionId,
    text,
  };
}

// ── Fixed fixture data (mirrors RTO.26A stages 1–5) ───────────────────

function buildBranchScopedFixture() {
  const records = [];

  // Branch A: Competitor development
  const qA1 = createQuestion(
    "branch-competitor-development",
    "What evidence suggests competitors are actively developing similar products?"
  );
  records.push(qA1);

  const cA1 = createContribution(
    "branch-competitor-development",
    qA1.id,
    "The competitor has hired machine-learning engineers and presented at an industry conference about the same customer problem."
  );
  records.push(cA1);
  qA1.contributions.push(cA1.id);

  const qA2 = createQuestion(
    "branch-competitor-development",
    "What would clarify whether this activity is product development rather than general market positioning?"
  );
  records.push(qA2);

  // Branch B: Customer demand
  const qB1 = createQuestion(
    "branch-customer-demand",
    "What evidence do we have that customers will actually buy the product?"
  );
  records.push(qB1);

  const cB1 = createContribution(
    "branch-customer-demand",
    qB1.id,
    "One enterprise customer has expressed strong interest but has not yet signed a contract."
  );
  records.push(cB1);
  qB1.contributions.push(cB1.id);

  const qB2 = createQuestion(
    "branch-customer-demand",
    "How much revenue from other customers is sufficiently committed or probable?"
  );
  records.push(qB2);

  // Late result scoped to Branch A / Contribution A1 (stage 5)
  const lateResultA1 = createLateResult(
    "branch-competitor-development",
    cA1.id,
    "This later interpretation relates to Contribution A1."
  );
  records.push(lateResultA1);

  return {
    // Records keyed by branch provenance
    allRecords: records,
    questions: {
      a1: qA1, a2: qA2, b1: qB1, b2: qB2,
    },
    contributions: { a1: cA1, b1: cB1 },
    lateResults: { a1: lateResultA1 },
  };
}

// ── Branch-scoped retrieval (explicit provenance only) ─────────────────

/**
 * getBranchReasoning(records, branchId)
 * Returns ONLY records whose `branchId` matches. No semantic filtering.
 */
function getBranchReasoning(allRecords, branchId) {
  return allRecords.filter(r => r.branchId === branchId);
}

// ── Branch-to-label mapping (UI layer only — not provenance logic) ─────

const BRANCH_META = {
  "branch-competitor-development": {
    id: "branch-a",
    label: "Competitor development",
    origin: "Whether competitors are developing similar products and when they might release them",
  },
  "branch-customer-demand": {
    id: "branch-b",
    label: "Customer demand",
    origin: "How many customers will buy the product, and what revenue that represents",
  },
};

// ── Exported interface for UI consumption ────────────────────────────────

export function useBranchScopedFixture() {
  const fixture = buildBranchScopedFixture();
  const allRecords = fixture.allRecords;

  return {
    /** Return branch-local question records as node-like objects. */
    getBranchQuestions(branchId) {
      const recs = getBranchReasoning(allRecords, branchId);
      return recs
        .filter(r => !r.questionId && !r.id.startsWith("late"))
        .map(q => ({
          id: q.id,
          label: q.text,
          kind: "unknown",
          status: "unresolved",
          _isFixtureQuestion: true,
          contributions: q.contributions || [],
        }));
    },

    /** Return branch-local contribution records scoped to active branch. */
    getBranchContributions(branchId) {
      const recs = getBranchReasoning(allRecords, branchId);
      return recs.filter(r => r.questionId && !r.id.startsWith("late"));
    },

    /** Check if a late result exists for the given contribution. */
    hasLateResult(contributionId) {
      return Object.values(fixture.lateResults).some(lr => lr.contributionId === contributionId);
    },

    /** Return late results scoped to a specific branch (for display). */
    getBranchLateResults(branchId) {
      const recs = getBranchReasoning(allRecords, branchId);
      return recs.filter(r => r.id.startsWith("late"));
    },

    /** Branch metadata for UI labels. */
    getBranchMeta(id) {
      // Reverse lookup: UI id → provenance branchId → meta
      const entry = Object.entries(BRANCH_META).find(
        ([, m]) => m.id === id
      );
      return entry ? { ...entry[1] } : null;
    },

    /** Return the fixed two-branch list for the switcher. */
    getBranches() {
      return Object.values(BRANCH_META).map(m => ({ ...m }));
    },

    /** Return all inferred questions across branches (flat list for post-Analyse surface). */
    getAllInferredQuestions() {
      const qA1 = this._qA1;
      const qA2 = this._qA2;
      const qB1 = this._qB1;
      const qB2 = this._qB2;
      if (!qA1 || !qA2 || !qB1 || !qB2) return [];
      return [
        { id: qA1.id, text: qA1.text, branchId: "branch-competitor-development" },
        { id: qA2.id, text: qA2.text, branchId: "branch-competitor-development" },
        { id: qB1.id, text: qB1.text, branchId: "branch-customer-demand" },
        { id: qB2.id, text: qB2.text, branchId: "branch-customer-demand" },
      ];
    },

    /** Return all records (for verification / debugging). */
    getAllRecords() {
      return allRecords;
    },

    /** Verify that a record's provenance matches its branch. */
    verifyProvenance(record, expectedBranchId) {
      return record?.branchId === expectedBranchId;
    },

    // ── RTO.26A cross-cutting invariants (deterministic checks) ──────

    _crossCuttingInvariants() {
      const branchAIds = new Set(getBranchReasoning(allRecords, "branch-competitor-development").map(r => r.id));
      const branchBIds = new Set(getBranchReasoning(allRecords, "branch-customer-demand").map(r => r.id));

      return {
        SEMANTIC_FILTERING_REQUIRED: false,
        KEYWORD_MATCHING_REQUIRED: false,
        WHOLE_STATE_RECONSTRUCTION_REQUIRED: false,
        GLOBAL_SELECTOR_REQUIRED: false,
        CROSS_BRANCH_CONTAMINATION: [...branchAIds].some(id => branchBIds.has(id)),
        NEXT_QUESTION_SELECTED: false,
      };
    },

    // Expose fixture for inspection (RTO.26A stages 1–5)
    _fixtureRecords: allRecords,
    _qA1: fixture.questions.a1,
    _qA2: fixture.questions.a2,
    _qB1: fixture.questions.b1,
    _qB2: fixture.questions.b2,
    _cA1: fixture.contributions.a1,
    _cB1: fixture.contributions.b1,
    _lateResultA1: fixture.lateResults.a1,
  };
}

export { buildBranchScopedFixture };