const asArray = (value) => Array.isArray(value) ? value : [];
const text = (value, fallback = "") => typeof value === "string" && value.trim() ? value.trim() : fallback;

const wearingRelations = new Set(["human_wearing", "human_wearing_static", "human_wearing_action"]);

export function compileSetDiversityPolicy(scenePolicy = {}) {
  const supportMode = text(scenePolicy.support_mode, "installed_or_environmental");
  const wearable = supportMode === "body_worn" || supportMode === "floor_supported" && scenePolicy.wearable_subtype === "footwear";
  return {
    schema_version: "1.0",
    minimum_distinct_content_signatures: 5,
    maximum_same_axis_framing: 2,
    maximum_human_wearing_pages: Number(scenePolicy.set_budget?.maximum_human_wearing_pages ?? (wearable ? 3 : 0)),
    required_relation_families: wearable
      ? ["isolated", "detail", "stable_display", "human_proximity", "human_wearing"]
      : ["isolated", "detail", "environmental", "human_context"],
    allowed_relation_modes: asArray(scenePolicy.allowed_relation_modes).length
      ? [...scenePolicy.allowed_relation_modes]
      : wearable
      ? ["isolated", "detail", "stable_display", "human_proximity", "human_wearing_static", "human_wearing_action"]
      : ["isolated", "detail", "stable_display", "environmental", "human_proximity", "human_handheld"],
    automatic_paid_regeneration: false,
  };
}

export function relationFamily(value = "") {
  const relation = text(value, "unknown");
  if (wearingRelations.has(relation)) return "human_wearing";
  if (relation.includes("detail") || relation.includes("material") || relation.includes("feature")) return "detail";
  if (relation.includes("isolated") || relation.includes("single accurate")) return "isolated";
  if (relation.includes("proximity")) return "human_proximity";
  if (relation.includes("handheld")) return "human_context";
  if (relation.includes("environment") || relation.includes("tabletop") || relation.includes("support") || relation.includes("display")) return "stable_display";
  return relation;
}

export function contentSignatureForPage({ page = {}, relationMode = "", index = 0 } = {}) {
  const shot = page.shot_spec || {};
  const evidence = asArray(page.evidence_refs).join("+") || `page:${index + 1}`;
  return [
    text(page.business_category, text(page.role, "page")),
    text(page.set_design?.render_family, "render"),
    text(shot.camera_axis, "axis"),
    text(shot.framing_mode, "framing"),
    text(relationMode || shot.interaction_mode, "relation"),
    evidence,
  ].join("|");
}

export function summarizePlannedDiversity(images = [], policy = {}) {
  const signatures = asArray(images).map((page) => text(page.set_design?.content_signature));
  const axisFraming = asArray(images).map((page) => `${text(page.shot_spec?.camera_axis)}|${text(page.shot_spec?.framing_mode)}`);
  const wearing = asArray(images).filter((page) => relationFamily(page.expected_page_compliance?.product_human_relation) === "human_wearing").length;
  const counts = (values) => Object.fromEntries([...new Set(values)].map((value) => [value, values.filter((candidate) => candidate === value).length]));
  return {
    distinct_content_signatures: new Set(signatures.filter(Boolean)).size,
    axis_framing_counts: counts(axisFraming),
    human_wearing_pages: wearing,
    policy: policy.schema_version ? policy : compileSetDiversityPolicy(policy),
  };
}