/**
 * interest_berths junction helpers.
 *
 * The junction is the source of truth for which berths an interest is
 * linked to. Callers should resolve "the berth for this deal" through
 * `getPrimaryBerth(interestId)` rather than reading the legacy
 * `interests.berth_id` column (slated for removal once every caller
 * is migrated - see plan §3.4).
 *
 * Role-flag semantics (see plan §1):
 *   - is_primary           : at most one row per interest. Templates,
 *                            forms, and "the berth for this deal"
 *                            UIs resolve through this row.
 *   - is_specific_interest : the berth shows as "Under Offer" on the
 *                            public map. False = legal/EOI-only link.
 *   - is_in_eoi_bundle     : covered by the interest's EOI signature.
 */

import { and, desc, eq, sql } from 'drizzle-orm';

import { db } from '@/lib/db';
import { interestBerths, type InterestBerth } from '@/lib/db/schema/interests';
import { berths } from '@/lib/db/schema/berths';

// ─── Reads ──────────────────────────────────────────────────────────────────

export interface PrimaryBerthRef {
  berthId: string;
  mooringNumber: string | null;
  isInEoiBundle: boolean;
  isSpecificInterest: boolean;
}

/**
 * The primary berth for an interest, if any. Resolves the row marked
 * `is_primary=true`; falls back to the most recently added berth row
 * when no row is flagged primary (defensive — the unique partial index
 * guarantees ≤1 primary, but reads should never throw on data drift).
 */
export async function getPrimaryBerth(interestId: string): Promise<PrimaryBerthRef | null> {
  const rows = await db
    .select({
      berthId: interestBerths.berthId,
      isPrimary: interestBerths.isPrimary,
      isSpecificInterest: interestBerths.isSpecificInterest,
      isInEoiBundle: interestBerths.isInEoiBundle,
      addedAt: interestBerths.addedAt,
      mooringNumber: berths.mooringNumber,
    })
    .from(interestBerths)
    .innerJoin(berths, eq(berths.id, interestBerths.berthId))
    .where(eq(interestBerths.interestId, interestId))
    .orderBy(desc(interestBerths.isPrimary), desc(interestBerths.addedAt));
  const first = rows[0];
  if (!first) return null;
  return {
    berthId: first.berthId,
    mooringNumber: first.mooringNumber,
    isInEoiBundle: first.isInEoiBundle,
    isSpecificInterest: first.isSpecificInterest,
  };
}

/**
 * Map { interestId → primary berth ref } for a batch of interest ids.
 * One round-trip; preferred for list pages over a per-row helper.
 */
export async function getPrimaryBerthsForInterests(
  interestIds: string[],
): Promise<Map<string, PrimaryBerthRef>> {
  if (interestIds.length === 0) return new Map();
  const rows = await db
    .select({
      interestId: interestBerths.interestId,
      berthId: interestBerths.berthId,
      isPrimary: interestBerths.isPrimary,
      isSpecificInterest: interestBerths.isSpecificInterest,
      isInEoiBundle: interestBerths.isInEoiBundle,
      addedAt: interestBerths.addedAt,
      mooringNumber: berths.mooringNumber,
    })
    .from(interestBerths)
    .innerJoin(berths, eq(berths.id, interestBerths.berthId))
    .where(sql`${interestBerths.interestId} = ANY(${interestIds})`)
    .orderBy(desc(interestBerths.isPrimary), desc(interestBerths.addedAt));

  const out = new Map<string, PrimaryBerthRef>();
  for (const r of rows) {
    if (out.has(r.interestId)) continue;
    out.set(r.interestId, {
      berthId: r.berthId,
      mooringNumber: r.mooringNumber,
      isInEoiBundle: r.isInEoiBundle,
      isSpecificInterest: r.isSpecificInterest,
    });
  }
  return out;
}

/** All berth links for a single interest, ordered with primary first. */
export async function listBerthsForInterest(
  interestId: string,
): Promise<Array<InterestBerth & { mooringNumber: string | null }>> {
  return db
    .select({
      id: interestBerths.id,
      interestId: interestBerths.interestId,
      berthId: interestBerths.berthId,
      isPrimary: interestBerths.isPrimary,
      isSpecificInterest: interestBerths.isSpecificInterest,
      isInEoiBundle: interestBerths.isInEoiBundle,
      eoiBypassReason: interestBerths.eoiBypassReason,
      eoiBypassedBy: interestBerths.eoiBypassedBy,
      eoiBypassedAt: interestBerths.eoiBypassedAt,
      addedBy: interestBerths.addedBy,
      addedAt: interestBerths.addedAt,
      notes: interestBerths.notes,
      mooringNumber: berths.mooringNumber,
    })
    .from(interestBerths)
    .innerJoin(berths, eq(berths.id, interestBerths.berthId))
    .where(eq(interestBerths.interestId, interestId))
    .orderBy(desc(interestBerths.isPrimary), desc(interestBerths.addedAt));
}

/** All interest links for a single berth (used by the recommender + admin UI). */
export async function listInterestsForBerth(berthId: string): Promise<Array<InterestBerth>> {
  return db
    .select()
    .from(interestBerths)
    .where(eq(interestBerths.berthId, berthId))
    .orderBy(desc(interestBerths.addedAt));
}

// ─── Writes ─────────────────────────────────────────────────────────────────

interface AddOrUpdateOpts {
  isPrimary?: boolean;
  isSpecificInterest?: boolean;
  isInEoiBundle?: boolean;
  addedBy?: string;
  notes?: string;
}

/**
 * Idempotently link a berth to an interest. If the row already exists,
 * provided flags are merged; otherwise a fresh row is inserted.
 *
 * When `isPrimary=true` is requested, the previous primary (if any) is
 * demoted in the same transaction so the unique partial index is never
 * violated.
 */
export async function upsertInterestBerth(
  interestId: string,
  berthId: string,
  opts: AddOrUpdateOpts = {},
): Promise<InterestBerth> {
  return db.transaction(async (tx) => {
    if (opts.isPrimary === true) {
      await tx
        .update(interestBerths)
        .set({ isPrimary: false })
        .where(and(eq(interestBerths.interestId, interestId), eq(interestBerths.isPrimary, true)));
    }
    const setForUpdate: Partial<InterestBerth> = {};
    if (opts.isPrimary !== undefined) setForUpdate.isPrimary = opts.isPrimary;
    if (opts.isSpecificInterest !== undefined)
      setForUpdate.isSpecificInterest = opts.isSpecificInterest;
    if (opts.isInEoiBundle !== undefined) setForUpdate.isInEoiBundle = opts.isInEoiBundle;
    if (opts.addedBy !== undefined) setForUpdate.addedBy = opts.addedBy;
    if (opts.notes !== undefined) setForUpdate.notes = opts.notes;

    const [row] = await tx
      .insert(interestBerths)
      .values({
        interestId,
        berthId,
        isPrimary: opts.isPrimary ?? false,
        isSpecificInterest: opts.isSpecificInterest ?? true,
        isInEoiBundle: opts.isInEoiBundle ?? false,
        addedBy: opts.addedBy,
        notes: opts.notes,
      })
      .onConflictDoUpdate({
        target: [interestBerths.interestId, interestBerths.berthId],
        set: setForUpdate,
      })
      .returning();
    return row!;
  });
}

/** Promote a single berth to primary for the interest. Demotes any prior primary. */
export async function setPrimaryBerth(interestId: string, berthId: string): Promise<void> {
  await upsertInterestBerth(interestId, berthId, { isPrimary: true });
}

/** Remove a berth from an interest. */
export async function removeInterestBerth(interestId: string, berthId: string): Promise<void> {
  await db
    .delete(interestBerths)
    .where(and(eq(interestBerths.interestId, interestId), eq(interestBerths.berthId, berthId)));
}