/**
 * Convert a brooks-lint Markdown report into a SARIF 2.1.0 log.
 *
 * SARIF is what GitHub Code Scanning ingests, so emitting it lets brooks-lint
 * findings appear inline on the PR "Files changed" tab. Findings are parsed by
 * report-parse.mjs; severity maps to SARIF levels (critical→error,
 * warning→warning, suggestion→note). File locations are best-effort: a finding
 * whose Symptom names a file gets a physicalLocation, otherwise it lands at the
 * run level with no location (still listed, just not pinned to a line).
 */

import { parseFindings, RISK_CATALOG } from "./report-parse.mjs";

const INFO_URI = "https://github.com/hyhmrright/brooks-lint";
// The field guide only publishes the six production-risk anchors (#r1–#r6);
// test risks live in the source file, so route T-codes there to avoid a dead link.
const GUIDE_URI = "https://hyhmrright.github.io/brooks-lint/guide.html";
const TEST_RISKS_URI =
  "https://github.com/hyhmrright/brooks-lint/blob/main/skills/_shared/test-decay-risks.md";

const LEVEL_BY_SEVERITY = {
  critical: "error",
  warning: "warning",
  suggestion: "note",
};

function helpUri(code) {
  return code.startsWith("T") ? TEST_RISKS_URI : `${GUIDE_URI}#${code.toLowerCase()}`;
}

/** PascalCase a risk name for use as a SARIF rule name. */
function ruleName(name) {
  return name.replace(/[^A-Za-z0-9]+/g, " ").trim().split(/\s+/).join("");
}

/** Stable, run-independent fingerprint so re-runs dedupe instead of stacking. */
function fingerprint(parts) {
  let hash = 5381;
  const str = parts.join(" ");
  for (let i = 0; i < str.length; i++) hash = ((hash * 33) ^ str.charCodeAt(i)) >>> 0;
  return hash.toString(16).padStart(8, "0");
}

function messageText(f) {
  const head = f.title ? `${f.riskName} — ${f.title}` : f.riskName;
  const fields = [
    ["Symptom", f.symptom],
    ["Source", f.source],
    ["Consequence", f.consequence],
    ["Remedy", f.remedy],
  ].filter(([, v]) => v);
  const body = fields.map(([k, v]) => `${k}: ${v}`).join("\n");
  return body ? `${head}\n\n${body}` : head;
}

/**
 * @param {string} report - the Markdown report
 * @param {{mode?: string, toolVersion?: string}} [opts]
 * @returns {object} a SARIF 2.1.0 log
 */
export function reportToSarif(report, opts = {}) {
  const { mode = "review", toolVersion = "0.0.0" } = opts;
  const findings = parseFindings(report);

  const usedCodes = [...new Set(findings.map((f) => f.riskCode).filter(Boolean))];
  const rules = usedCodes.map((code) => ({
    id: code,
    name: ruleName(RISK_CATALOG[code]),
    shortDescription: { text: RISK_CATALOG[code] },
    helpUri: helpUri(code),
  }));
  // Findings whose risk name didn't resolve fall back to ruleId BL000; declare
  // it so every emitted ruleId resolves to a rule (SARIF 2.1.0 expectation).
  if (findings.some((f) => !f.riskCode)) {
    rules.push({
      id: "BL000",
      name: "UncategorizedFinding",
      shortDescription: { text: "Uncategorized finding" },
    });
  }

  const results = findings.map((f) => {
    const result = {
      ruleId: f.riskCode ?? "BL000",
      level: LEVEL_BY_SEVERITY[f.severity] ?? "note",
      message: { text: messageText(f) },
      partialFingerprints: {
        brooksLint: fingerprint([f.riskCode ?? "", f.title, f.file ?? ""]),
      },
    };
    if (f.file) {
      result.locations = [{
        physicalLocation: {
          artifactLocation: { uri: f.file },
          ...(f.line ? { region: { startLine: f.line } } : {}),
        },
      }];
    }
    return result;
  });

  return {
    $schema: "https://json.schemastore.org/sarif-2.1.0.json",
    version: "2.1.0",
    runs: [{
      tool: {
        driver: {
          name: "brooks-lint",
          informationUri: INFO_URI,
          version: toolVersion,
          rules,
          properties: { mode },
        },
      },
      results,
    }],
  };
}