/** Schema-aligned, fail-closed HUX-08 research normalization. */

import {
  asRecord, boundedText, isHash, isId, isUtc, normalizeIdentity, normalizeScope,
  safeSourceUri, sameIdentity, sameScope,
} from "./security.ts";
import type {
  CitationView, Classification, HuxIdentity, NotebookStatus, NotebookView, PassageView,
  ProvenanceView, RawResearchEnvelope, ResearchPage, ResearchScope, SourceKind, SourceView, Support,
} from "./types.ts";

export const FOUNDATION_FLAG = "hux.foundation";
export const FRIENDLY_MODES_FLAG = "hux.friendly_modes";
export const RESEARCH_FLAG = "hux.research";
const KINDS = new Set<SourceKind>(["web", "document", "artifact", "memory", "tool_output", "dataset"]);
const CLASSIFICATIONS = new Set<Classification>(["primary", "secondary", "unknown"]);
const SUPPORT = new Set<Support>(["supports", "partially_supports", "contradicts", "unverified"]);
const STATUSES = new Set<NotebookStatus>(["open", "answered", "abandoned"]);
const MAX_RECORDS = 500;

export function researchEnabled(flags?: Iterable<string>): boolean {
  const active = new Set(flags || []);
  return [FOUNDATION_FLAG, FRIENDLY_MODES_FLAG, RESEARCH_FLAG].every((flag) => active.has(flag));
}

function provenance(raw: unknown, conversationId: string): ProvenanceView | null | false {
  if (raw === undefined) return null;
  const value = asRecord(raw);
  const actor = asRecord(value?.actor);
  if (!value || !actor || !["chat", "worker", "telegram", "voice", "api"].includes(String(value.surface)) ||
      !["user", "assistant", "tool", "system", "operator"].includes(String(actor.type)) ||
      !boundedText(actor.id, 1, 120) || !isUtc(value.recorded_at) ||
      (value.conversation_id !== undefined && value.conversation_id !== conversationId) ||
      (value.run_id !== undefined && !boundedText(value.run_id, 1, 120))) return false;
  return {surface: value.surface as ProvenanceView["surface"], actorType: actor.type as ProvenanceView["actorType"],
    recordedAt: value.recorded_at, runId: value.run_id as string | undefined || null};
}

function source(raw: unknown, conversationId: string): SourceView | null {
  const value = asRecord(raw);
  if (!value || value.schema !== "hux.source.v1" || !isId(value.id, "src") ||
      !KINDS.has(value.kind as SourceKind) || !boundedText(value.title, 1, 300) ||
      !boundedText(value.publisher ?? "", 0, 200) || !isUtc(value.retrieved_at) ||
      !CLASSIFICATIONS.has(value.classification as Classification) ||
      (value.published_at !== undefined && !isUtc(value.published_at)) ||
      (isUtc(value.published_at) && value.published_at > value.retrieved_at) ||
      (value.content_hash !== undefined && !isHash(value.content_hash))) return null;
  const uri = safeSourceUri(value.uri);
  if (value.uri !== undefined && value.uri !== "" && !uri) return null;
  const origin = provenance(value.provenance, conversationId);
  if (origin === false) return null;
  return {id: value.id, kind: value.kind as SourceKind, title: value.title,
    publisher: value.publisher as string | undefined || "", publishedAt: value.published_at as string | undefined || null,
    retrievedAt: value.retrieved_at, classification: value.classification as Classification,
    uri, provenance: origin};
}

function locator(raw: unknown): string | null {
  if (raw === undefined) return "";
  const value = asRecord(raw);
  if (!value || Object.keys(value).some((key) => !["page", "selector", "line_start", "line_end", "char_start", "char_end"].includes(key))) return null;
  const positive = (item: unknown) => Number.isSafeInteger(item) && (item as number) >= 1;
  const natural = (item: unknown) => Number.isSafeInteger(item) && (item as number) >= 0;
  if ((value.page !== undefined && !positive(value.page)) ||
      (value.selector !== undefined && !boundedText(value.selector, 0, 500)) ||
      (value.line_start !== undefined && !positive(value.line_start)) ||
      (value.line_end !== undefined && !positive(value.line_end)) ||
      (value.char_start !== undefined && !natural(value.char_start)) ||
      (value.char_end !== undefined && !natural(value.char_end)) ||
      (positive(value.line_start) && positive(value.line_end) && (value.line_end as number) < (value.line_start as number)) ||
      (natural(value.char_start) && natural(value.char_end) && (value.char_end as number) < (value.char_start as number))) return null;
  const parts = [value.page && `page ${value.page}`, value.selector && String(value.selector),
    value.line_start && `lines ${value.line_start}${value.line_end ? `–${value.line_end}` : ""}`,
    value.char_start !== undefined && `characters ${value.char_start}${value.char_end !== undefined ? `–${value.char_end}` : ""}`];
  return parts.filter(Boolean).join(" · ");
}

function passage(raw: unknown, sources: ReadonlySet<string>): PassageView | null {
  const value = asRecord(raw);
  if (!value || value.schema !== "hux.passage.v1" || !isId(value.id, "psg") ||
      !isId(value.source_id, "src") || !sources.has(value.source_id) ||
      !boundedText(value.text, 1, 4_000) || !isHash(value.hash)) return null;
  const position = locator(value.locator);
  return position === null ? null : {id: value.id, sourceId: value.source_id, text: value.text, locator: position};
}

function citation(raw: unknown, passages: ReadonlySet<string>): CitationView | null {
  const value = asRecord(raw);
  if (!value || value.schema !== "hux.citation.v1" || !isId(value.id, "cit") ||
      !boundedText(value.message_id, 1, 120) || !boundedText(value.claim, 1, 1_000) ||
      !Array.isArray(value.passage_ids) || value.passage_ids.length < 1 || value.passage_ids.length > 32 ||
      new Set(value.passage_ids).size !== value.passage_ids.length ||
      value.passage_ids.some((id) => !isId(id, "psg") || !passages.has(id)) ||
      !SUPPORT.has(value.support as Support) || !boundedText(value.note ?? "", 0, 500)) return null;
  return {id: value.id, messageId: value.message_id, claim: value.claim,
    passageIds: [...value.passage_ids] as string[], support: value.support as Support,
    note: value.note as string | undefined || ""};
}

function idList(raw: unknown, prefix: string, allowed: ReadonlySet<string>): string[] | null {
  return Array.isArray(raw) && raw.length <= MAX_RECORDS && new Set(raw).size === raw.length &&
    raw.every((id) => isId(id, prefix) && allowed.has(id)) ? [...raw] as string[] : null;
}

function textList(raw: unknown): string[] | null {
  return Array.isArray(raw) && raw.length <= 64 && raw.every((item) => boundedText(item, 1, 500)) ? [...raw] : null;
}

function notebook(raw: unknown, scope: ResearchScope, sources: ReadonlySet<string>,
  passages: ReadonlySet<string>, citations: ReadonlyMap<string, CitationView>): NotebookView | null {
  const value = asRecord(raw);
  if (!value || value.schema !== "hux.research_notebook.v1" || !isId(value.id, "nb") ||
      value.conversation_id !== scope.conversationId || !boundedText(value.question, 1, 1_000) ||
      !STATUSES.has(value.status as NotebookStatus) || !isUtc(value.updated_at)) return null;
  const sourceIds = idList(value.source_ids, "src", sources);
  const passageIds = idList(value.passage_ids, "psg", passages);
  const citationIds = idList(value.citation_ids, "cit", new Set(citations.keys()));
  const assumptions = textList(value.assumptions);
  const unresolved = textList(value.unresolved_questions);
  if (!sourceIds || !passageIds || !citationIds || !assumptions || !unresolved) return null;
  const notes = citationIds.map((id) => citations.get(id)?.note || "").filter(Boolean);
  return {id: value.id, question: value.question, status: value.status as NotebookStatus,
    sourceIds, passageIds, citationIds, assumptions, unresolvedQuestions: unresolved,
    notes, updatedAt: value.updated_at};
}

function unique<T extends {id: string}>(values: Array<T | null>): {items: T[]; rejected: number} {
  const seen = new Set<string>();
  const items = values.filter((item): item is T => Boolean(item && !seen.has(item.id) && seen.add(item.id)));
  return {items, rejected: values.length - items.length};
}

export function normalizeResearchPage(raw: RawResearchEnvelope, expected: HuxIdentity,
  scope: ResearchScope): ResearchPage | null {
  if (!raw || typeof raw !== "object" || raw.schema !== "hux.research_page.v1" || raw.api_version !== "hux.v1" ||
      !sameIdentity(normalizeIdentity(raw.identity), expected) || !sameScope(normalizeScope(raw.binding), scope) ||
      !Array.isArray(raw.sources) || raw.sources.length > MAX_RECORDS || !Array.isArray(raw.passages) ||
      raw.passages.length > MAX_RECORDS || !Array.isArray(raw.citations) || raw.citations.length > MAX_RECORDS ||
      !Array.isArray(raw.notebooks) || raw.notebooks.length > 100) return null;
  const sourceResult = unique(raw.sources.map((item) => source(item, scope.conversationId)));
  const sourceIds = new Set(sourceResult.items.map((item) => item.id));
  const passageResult = unique(raw.passages.map((item) => passage(item, sourceIds)));
  const passageIds = new Set(passageResult.items.map((item) => item.id));
  const citationResult = unique(raw.citations.map((item) => citation(item, passageIds)));
  const citationMap = new Map(citationResult.items.map((item) => [item.id, item]));
  const notebookResult = unique(raw.notebooks.map((item) => notebook(item, scope, sourceIds, passageIds, citationMap)));
  return {sources: sourceResult.items, passages: passageResult.items, citations: citationResult.items,
    notebooks: notebookResult.items, rejected: sourceResult.rejected + passageResult.rejected +
      citationResult.rejected + notebookResult.rejected};
}