/**
 * `tailwind/arbitrary-spacing` — flags arbitrary Tailwind spacing utilities
 * that cannot be proven to sit on the configured spacing scale.
 */

import type { FactIndex, TailwindClassFact } from "../facts/index.js";

import { makeFinding } from "./finding.js";
import type { Finding, FindingReplaceClassTokenFix } from "./types.js";
import {
  matchesScale,
  normalizeLengthForScale,
  parseLengthValue,
  readUsageNode,
} from "./utils.js";

export const RULE_ID = "tailwind/arbitrary-spacing";
export const RULE_VERSION = "1";

const SPACING_UTILITY_TO_PROPERTY: ReadonlyMap<string, string> = new Map([
  ["m", "margin"],
  ["mt", "margin"],
  ["mr", "margin"],
  ["mb", "margin"],
  ["ml", "margin"],
  ["ms", "margin"],
  ["me", "margin"],
  ["mx", "margin"],
  ["my", "margin"],
  ["p", "padding"],
  ["pt", "padding"],
  ["pr", "padding"],
  ["pb", "padding"],
  ["pl", "padding"],
  ["ps", "padding"],
  ["pe", "padding"],
  ["px", "padding"],
  ["py", "padding"],
  ["gap", "gap"],
  ["gap-x", "gap"],
  ["gap-y", "gap"],
  ["space-x", "gap"],
  ["space-y", "gap"],
] as const);

export function ruleTailwindArbitrarySpacing(ix: FactIndex): Finding[] {
  const findings: Finding[] = [];

  for (const klass of ix.byKind("tailwind_class")) {
    if (klass.value.kind !== "arbitrary") continue;

    const property = SPACING_UTILITY_TO_PROPERTY.get(klass.utility);
    if (!property) continue;

    const policy = ix.policy.propertyScale(property);
    if (!policy) continue;
    const scale = ix.policy.scale(policy.scale);
    if (!scale) continue;
    const allowed = ix.policy.scaleValues(policy.scale).map((v) => v.value);
    if (allowed.length === 0) continue;

    const parsed = parseLengthValue(klass.value.raw);
    const normalized = parsed ? normalizeLengthForScale(parsed, scale) : null;
    if (normalized && matchesScale(normalized.value, allowed)) continue;

    const node = readUsageNode(ix, klass.nodeId);
    const evidenceIds = node
      ? [node.id, klass.id, policy.id, scale.id]
      : [klass.id, policy.id, scale.id];

    const fix = buildFix(klass);

    findings.push(
      makeFinding({
        ruleId: RULE_ID,
        ruleVersion: RULE_VERSION,
        severity: policy.severity,
        message: `\`${klass.raw}\` is an arbitrary spacing value not on the project's spacing scale.`,
        location: klass.location,
        evidence: ix.evidence(evidenceIds),
        fingerprintIdentity: {
          source: "tailwind_class",
          file: klass.file,
          nodeId: klass.nodeId,
          originPath: klass.originPath,
          raw: klass.raw,
          utility: klass.utility,
          value: klass.value.raw,
        },
        fix,
        attributes: {
          rawClass: klass.raw,
          rawValue: klass.value.raw,
          utility: klass.utility,
          property,
          scale: scale.name,
          allowed,
          normalizedValue: normalized?.value,
          normalizedUnit: normalized ? scale.unit : undefined,
          assumedRootFontSizePx: normalized?.assumedRootFontSizePx,
          assumedEmBasePx: normalized?.assumedEmBasePx,
          source: "tailwind",
        },
      }),
    );
  }

  return findings;
}

function buildFix(klass: TailwindClassFact): FindingReplaceClassTokenFix {
  return {
    kind: "replaceClassToken",
    title: `Review ${klass.raw}`,
    from: klass.raw,
    to: null,
    utility: klass.utility,
    deterministic: false,
  };
}