import { eq, and, inArray } from "drizzle-orm";
import { database } from "~/database/context";
import * as schema from "~/database/schema";

export type ParticipantResult = typeof schema.seasonParticipantResults.$inferSelect;
export type ParticipantResultWithParticipant = ParticipantResult & {
  participant: { id: string; name: string } | null;
};
export type NewParticipantResult = typeof schema.seasonParticipantResults.$inferInsert;

export async function createParticipantResult(
  data: NewParticipantResult
): Promise<ParticipantResult> {
  const db = database();
  const [result] = await db
    .insert(schema.seasonParticipantResults)
    .values(data)
    .returning();
  return result;
}

export async function createManyParticipantResults(
  data: NewParticipantResult[]
): Promise<ParticipantResult[]> {
  const db = database();
  return await db
    .insert(schema.seasonParticipantResults)
    .values(data)
    .returning();
}

export async function findParticipantResultById(
  id: string
): Promise<ParticipantResult | undefined> {
  const db = database();
  return await db.query.seasonParticipantResults.findFirst({
    where: eq(schema.seasonParticipantResults.id, id),
    with: {
      participant: true,
      sportsSeason: {
        with: {
          sport: true,
        },
      },
    },
  });
}

export async function findParticipantResultByParticipantId(
  participantId: string
): Promise<ParticipantResult | undefined> {
  const db = database();
  return await db.query.seasonParticipantResults.findFirst({
    where: eq(schema.seasonParticipantResults.participantId, participantId),
    with: {
      participant: true,
      sportsSeason: {
        with: {
          sport: true,
        },
      },
    },
  });
}

export async function findParticipantResultsBySportsSeasonId(
  sportsSeasonId: string
): Promise<ParticipantResultWithParticipant[]> {
  const db = database();
  return await db.query.seasonParticipantResults.findMany({
    where: eq(schema.seasonParticipantResults.sportsSeasonId, sportsSeasonId),
    orderBy: (results, { asc }) => [asc(results.finalPosition)],
    with: {
      participant: true,
    },
  });
}

/**
 * Tallies how many participants share each scoring placement, per sports season.
 *
 * Pure counterpart to getSharedPlacementCounts, for callers that already hold the
 * result rows. Split out so there is exactly one definition of what "tied" means
 * — the whole point of this module is that every screen counts ties identically.
 *
 * Positions <= 0 (no scoring placement) are excluded.
 */
export function countSharedPlacements(
  rows: Array<{ sportsSeasonId: string; finalPosition: number | null }>
): Map<string, Map<number, number>> {
  const counts = new Map<string, Map<number, number>>();

  for (const row of rows) {
    if (row.finalPosition === null || row.finalPosition <= 0) continue;
    let bySeason = counts.get(row.sportsSeasonId);
    if (!bySeason) {
      bySeason = new Map<number, number>();
      counts.set(row.sportsSeasonId, bySeason);
    }
    bySeason.set(row.finalPosition, (bySeason.get(row.finalPosition) ?? 0) + 1);
  }

  return counts;
}

/**
 * How many participants share each scoring placement, per sports season.
 *
 * Returns sportsSeasonId → (finalPosition → count). Used to split a tied
 * placement's points across the tied participants (see calculatePickPoints).
 *
 * The count spans EVERY result in the sports season, not just drafted ones — a
 * golfer tied for 8th with an undrafted player still only earns half the 8th
 * place points, so narrowing this query to drafted participants would silently
 * over-award.
 *
 * Callers that look up a position with no entry should treat it as 1 (no tie).
 */
export async function getSharedPlacementCounts(
  sportsSeasonIds: string[],
  providedDb?: ReturnType<typeof database>
): Promise<Map<string, Map<number, number>>> {
  if (sportsSeasonIds.length === 0) return new Map();

  const db = providedDb || database();
  const rows = await db.query.seasonParticipantResults.findMany({
    where: inArray(schema.seasonParticipantResults.sportsSeasonId, sportsSeasonIds),
    columns: { sportsSeasonId: true, finalPosition: true },
  });

  return countSharedPlacements(rows);
}

/**
 * Convenience lookup over getSharedPlacementCounts' result. Missing entries mean
 * no other participant shares the placement, so the tie count is 1.
 */
export function lookupSharedPlacementCount(
  counts: Map<string, Map<number, number>>,
  sportsSeasonId: string,
  finalPosition: number
): number {
  return counts.get(sportsSeasonId)?.get(finalPosition) ?? 1;
}

export async function updateParticipantResult(
  id: string,
  data: Partial<NewParticipantResult>
): Promise<ParticipantResult> {
  const db = database();
  const [result] = await db
    .update(schema.seasonParticipantResults)
    .set({ ...data, updatedAt: new Date() })
    .where(eq(schema.seasonParticipantResults.id, id))
    .returning();
  return result;
}

export async function deleteParticipantResult(id: string): Promise<void> {
  const db = database();
  await db.delete(schema.seasonParticipantResults).where(eq(schema.seasonParticipantResults.id, id));
}

export async function deleteParticipantResultsBySportsSeasonId(
  sportsSeasonId: string,
  providedDb?: ReturnType<typeof database>
): Promise<void> {
  const db = providedDb || database();
  await db
    .delete(schema.seasonParticipantResults)
    .where(eq(schema.seasonParticipantResults.sportsSeasonId, sportsSeasonId));
}

/**
 * Set result for a participant in a sports season
 * Points are calculated on-demand based on each fantasy league's scoring rules
 */
export async function setParticipantResult(
  participantId: string,
  sportsSeasonId: string,
  finalPosition: number,
  qualifyingPoints?: number,
  notes?: string
): Promise<ParticipantResult> {
  const db = database();

  // Check if result already exists
  const existing = await db.query.seasonParticipantResults.findFirst({
    where: and(
      eq(schema.seasonParticipantResults.participantId, participantId),
      eq(schema.seasonParticipantResults.sportsSeasonId, sportsSeasonId)
    ),
  });

  if (existing) {
    // Update existing result
    return await updateParticipantResult(existing.id, {
      finalPosition,
      qualifyingPoints: qualifyingPoints?.toString(),
      notes,
    });
  } else {
    // Create new result
    return await createParticipantResult({
      participantId,
      sportsSeasonId,
      finalPosition,
      qualifyingPoints: qualifyingPoints?.toString(),
      notes,
    });
  }
}