import type { TenantDb } from "@/server/db";
import type { ControlDescription } from "@prisma/client";
import { controlTitle, compareControl } from "@/lib/control-titles";
import type { DraftInput } from "@/server/ai/draft-control-description";

/**
 * Gemeinsamer Server-Kontext für die Control-Beschreibungen (VDA-ISA-Spalte 4).
 * Bündelt je Control die Kontrollfrage, die Anforderungs-Bullets aus
 * `PolicyRequirement`, die verknüpften Richtlinien/Verfahren (`PolicyDocument`)
 * sowie den vorhandenen Nachweisstand (`Evidence`) und die bereits erfassten
 * `ControlDescription`-Zeilen. Wird von der Controls-Seite, der ABGABE-Vorschau
 * und den KI-/Speicher-Actions geteilt (eine Aufbereitungsstelle).
 */

export type DescriptionStatus = "open" | "draft" | "confirmed";

export interface RequirementBullet {
  reqId: string;
  obligation: string; // MUSS | SOLL
  requirement: string;
  implementation: string;
  /** Verknüpfte Dokumente (policyCode + vaCodes → PolicyDocument). */
  documents: { code: string; title: string; version: string; status: string }[];
  /** Bereits erfasste Beschreibung (Entwurf/übernommen) oder null. */
  description: {
    draftText: string | null;
    sourceRef: string | null;
    confidence: string | null;
    status: DescriptionStatus;
    openAnswer: string | null;
  } | null;
  /** True, wenn zum Control mindestens ein Nachweis existiert. */
  hasEvidence: boolean;
}

/** Status-Ampel je Control: grün (alle übernommen) / orange (teils) / rot (keine). */
export type ControlLamp = "green" | "amber" | "red";

export interface ControlGroup {
  control: string;
  frage: string;
  bullets: RequirementBullet[];
  /** Nachweistitel des Controls (Evidence). */
  evidence: string[];
  lamp: ControlLamp;
}

function descStatus(row: ControlDescription | undefined): DescriptionStatus {
  const s = row?.status;
  return s === "confirmed" || s === "draft" ? s : "open";
}

/** Ampel aus den Beschreibungs-Status der Bullets. */
function lampOf(bullets: RequirementBullet[]): ControlLamp {
  if (bullets.length === 0) return "red";
  const confirmed = bullets.filter((b) => b.description?.status === "confirmed").length;
  if (confirmed === bullets.length) return "green";
  const started = bullets.filter((b) => b.description && b.description.status !== "open").length;
  return started > 0 ? "amber" : "red";
}

/** Lädt alle Controls (mit Anforderungs-Bullets, Dokumenten, Nachweisen, Beschreibungen). */
export async function buildControlGroups(db: TenantDb): Promise<ControlGroup[]> {
  const [reqs, docs, evidence, descriptions] = await Promise.all([
    db.policyRequirement.findMany({
      where: { archivedAt: null },
      select: { reqId: true, control: true, obligation: true, requirement: true, implementation: true, policyCode: true, vaCodes: true },
    }),
    db.policyDocument.findMany({ where: { archivedAt: null }, select: { code: true, title: true, version: true, status: true } }),
    db.evidence.findMany({ where: { control: { not: null } }, select: { control: true, title: true } }),
    db.controlDescription.findMany(),
  ]);

  const docByCode = new Map(docs.map((d) => [d.code, d]));
  const descByReq = new Map(descriptions.map((d) => [d.reqId, d]));
  const evidenceByControl = new Map<string, string[]>();
  for (const e of evidence) {
    if (!e.control) continue;
    const list = evidenceByControl.get(e.control) ?? [];
    list.push(e.title);
    evidenceByControl.set(e.control, list);
  }

  const byControl = new Map<string, RequirementBullet[]>();
  for (const r of reqs) {
    const codes = [r.policyCode, ...r.vaCodes].filter(Boolean);
    const documents = [...new Set(codes)]
      .map((c) => docByCode.get(c))
      .filter((d): d is NonNullable<typeof d> => Boolean(d))
      .map((d) => ({ code: d.code, title: d.title, version: d.version, status: d.status }));
    const row = descByReq.get(r.reqId);
    const bullet: RequirementBullet = {
      reqId: r.reqId,
      obligation: r.obligation,
      requirement: r.requirement,
      implementation: r.implementation,
      documents,
      description: row
        ? { draftText: row.draftText, sourceRef: row.sourceRef, confidence: row.confidence, status: descStatus(row), openAnswer: row.openAnswer }
        : null,
      hasEvidence: (evidenceByControl.get(r.control)?.length ?? 0) > 0,
    };
    const list = byControl.get(r.control) ?? [];
    list.push(bullet);
    byControl.set(r.control, list);
  }

  return [...byControl.entries()]
    .sort((a, b) => compareControl(a[0], b[0]))
    .map(([control, bullets]) => ({
      control,
      frage: controlTitle(control),
      bullets: bullets.sort((a, b) => a.reqId.localeCompare(b.reqId, undefined, { numeric: true })),
      evidence: evidenceByControl.get(control) ?? [],
      lamp: lampOf(bullets),
    }));
}

/**
 * Baut den KI-Eingabekontext für eine einzelne Anforderung (reqId). Liefert
 * `null`, wenn die Anforderung nicht existiert. Wird von der Draft-Action genutzt.
 */
export async function buildDraftInput(db: TenantDb, reqId: string): Promise<DraftInput | null> {
  const r = await db.policyRequirement.findFirst({
    where: { reqId, archivedAt: null },
    select: { reqId: true, control: true, obligation: true, requirement: true, implementation: true, policyCode: true, vaCodes: true },
  });
  if (!r) return null;

  const codes = [...new Set([r.policyCode, ...r.vaCodes].filter(Boolean))];
  const [docs, evidence] = await Promise.all([
    db.policyDocument.findMany({ where: { code: { in: codes }, archivedAt: null }, select: { code: true, title: true, version: true, status: true } }),
    db.evidence.findMany({ where: { control: r.control }, select: { title: true } }),
  ]);

  return {
    control: r.control,
    reqId: r.reqId,
    obligation: r.obligation,
    requirement: r.requirement,
    implementation: r.implementation,
    documents: docs.map((d) => ({ code: d.code, title: d.title, version: d.version, status: d.status })),
    evidence: evidence.map((e) => e.title),
  };
}