import type { UiImpact, WorkflowFacts } from "./domain.ts";

const IMPACT_RANK: Record<UiImpact, number> = {
  none: 0,
  minor: 1,
  "non-trivial": 2,
};

const NON_TRIVIAL_TERMS = new Set([
  "accessibility",
  "a11y",
  "component",
  "dialog",
  "editor",
  "form",
  "layout",
  "modal",
  "navigation",
  "onboarding",
  "page",
  "redesign",
  "responsive",
  "settings",
  "sidebar",
  "wizard",
]);

const NON_TRIVIAL_PATH_PARTS = [
  "/+page.",
  "/dialog.",
  "/form.",
  "/layout.",
  "/modal.",
  "/navigation.",
  "/nav.",
  "/settings.",
  "/shell.",
  "/sidebar.",
  "/accessibility/",
  "/onboarding/",
  "/settings/",
];

const UI_SOURCE_SUFFIXES = [
  ".astro",
  ".css",
  ".html",
  ".jsx",
  ".less",
  ".scss",
  ".svelte",
  ".tsx",
  ".vue",
];

export interface UiImpactPolicyInput {
  plannerImpact: UiImpact;
  plannerEvidence: string[];
  affectedSurfaces: string[];
  facts: WorkflowFacts;
}

export interface UiImpactPolicyResult {
  impact: UiImpact;
  evidence: string[];
  affectedSurfaces: string[];
  objectiveImpact: UiImpact;
}

function objectiveEvidence(facts: WorkflowFacts) {
  const evidence: string[] = [];
  for (const term of facts.requestTerms) {
    if (NON_TRIVIAL_TERMS.has(term.toLowerCase())) {
      evidence.push(`Request includes non-trivial UI signal: ${term}`);
    }
  }
  for (const candidatePath of facts.candidatePaths) {
    const normalized = `/${candidatePath.toLowerCase().replaceAll("\\", "/")}`;
    const isUiSource = UI_SOURCE_SUFFIXES.some((suffix) =>
      normalized.endsWith(suffix),
    );
    if (
      isUiSource &&
      NON_TRIVIAL_PATH_PARTS.some((part) => normalized.includes(part))
    ) {
      evidence.push(`Affected path has non-trivial UI responsibility: ${candidatePath}`);
    }
  }
  for (const tag of [...facts.tags, ...facts.riskTags]) {
    if (NON_TRIVIAL_TERMS.has(tag.toLowerCase())) {
      evidence.push(`Repository evidence includes non-trivial UI signal: ${tag}`);
    }
  }
  return evidence;
}

export function enforceUiImpact(input: UiImpactPolicyInput): UiImpactPolicyResult {
  const objective = objectiveEvidence(input.facts);
  const objectiveImpact: UiImpact =
    objective.length > 0 ? "non-trivial" : input.plannerImpact;
  const impact =
    IMPACT_RANK[objectiveImpact] > IMPACT_RANK[input.plannerImpact]
      ? objectiveImpact
      : input.plannerImpact;
  return {
    impact,
    objectiveImpact,
    evidence: [...new Set([...input.plannerEvidence, ...objective])],
    affectedSurfaces: [...new Set(input.affectedSurfaces)],
  };
}