/**
 * Finding builder — assembles a `Finding` and computes its fingerprint.
 *
 * The fingerprint is a content-addressed hash of a small identity tuple chosen
 * by each rule. It is *not* the source location: two findings at different
 * lines for the same offending value should have different fingerprints, but
 * adding a blank line above them must not change either fingerprint. Rules
 * pick identity inputs that capture "what's wrong" (file, ruleId, componentId,
 * prop, property, value) without leaning on lineNumber/column.
 */

import type { GovernanceSeverity } from "../governance.js";
import type { FactEvidence, FactLocation } from "../facts/index.js";
import { canonicalJson, hash64Hex } from "../facts/ids.js";
import { byRuleId } from "../codes/index.js";
import { normalizeFinding, normalizeSeverity } from "../schemas/index.js";
import type { Severity } from "../schemas/index.js";

import type { Finding, FindingFix } from "./types.js";

export interface MakeFindingInput {
  ruleId: string;
  ruleVersion: string;
  severity: GovernanceSeverity | Severity;
  message: string;
  location: FactLocation;
  evidence: FactEvidence[];
  fingerprintIdentity: Record<string, unknown>;
  fix?: FindingFix;
  attributes?: Record<string, unknown>;
}

export function makeFinding(input: MakeFindingInput): Finding {
  if (input.evidence.length === 0) {
    throw new Error(`makeFinding(${input.ruleId}): findings must carry at least one evidence fact`);
  }
  const fingerprint = hash64Hex(
    canonicalJson({ ruleId: input.ruleId, ...input.fingerprintIdentity })
  );
  const code = byRuleId.get(input.ruleId);
  return normalizeFinding({
    ruleId: input.ruleId,
    ruleVersion: input.ruleVersion,
    severity: normalizeSeverity(input.severity),
    code: code?.code,
    helpUrl: code?.explainUrl,
    message: input.message,
    fingerprint,
    location: input.location,
    evidence: input.evidence,
    fix: input.fix,
    attributes: input.attributes,
  });
}