import { database } from "~/database/context";
import * as schema from "~/database/schema";
import { eq, and, desc, asc, gte, lte } from "drizzle-orm";
import { recalculateAffectedLeagues } from "./scoring-calculator";
import { recalculateParticipantQP } from "./qualifying-points";

export type EventType = "playoff_game" | "major_tournament" | "final_standings" | "schedule_event";

export function getEventTypeLabel(eventType: string): string {
  switch (eventType) {
    case "playoff_game": return "Bracket";
    case "major_tournament": return "Major Tournament";
    case "final_standings": return "Final Standings";
    case "schedule_event": return "Non-Scoring";
    default: return eventType;
  }
}

export interface CreateScoringEventData {
  sportsSeasonId: string;
  name: string;
  eventDate?: Date;
  eventType: EventType;
  isQualifyingEvent?: boolean;
  // Template system fields (Phase 2.6)
  bracketTemplateId?: string;
  scoringStartsAtRound?: string;
}

export interface UpdateScoringEventData {
  name?: string;
  eventDate?: Date;
  isComplete?: boolean;
  completedAt?: Date;
  bracketTemplateId?: string;
  scoringStartsAtRound?: string;
}

/**
 * Create a new scoring event
 */
export async function createScoringEvent(
  data: CreateScoringEventData,
  providedDb?: ReturnType<typeof database>
) {
  const db = providedDb || database();

  const [event] = await db
    .insert(schema.scoringEvents)
    .values({
      sportsSeasonId: data.sportsSeasonId,
      name: data.name,
      eventDate: data.eventDate ? data.eventDate.toISOString().split('T')[0] : undefined,
      eventType: data.eventType,
      isQualifyingEvent: data.isQualifyingEvent || false,
      bracketTemplateId: data.bracketTemplateId,
      scoringStartsAtRound: data.scoringStartsAtRound,
      isComplete: false,
    })
    .returning();

  return event;
}

/**
 * Get a scoring event by ID
 */
export async function getScoringEventById(
  eventId: string,
  providedDb?: ReturnType<typeof database>
) {
  const db = providedDb || database();

  return await db.query.scoringEvents.findFirst({
    where: eq(schema.scoringEvents.id, eventId),
    with: {
      sportsSeason: {
        with: {
          sport: true,
        },
      },
    },
  });
}

/**
 * Get all scoring events for a sports season
 */
export async function getScoringEventsForSportsSeason(
  sportsSeasonId: string,
  providedDb?: ReturnType<typeof database>
) {
  const db = providedDb || database();

  return await db.query.scoringEvents.findMany({
    where: eq(schema.scoringEvents.sportsSeasonId, sportsSeasonId),
    orderBy: [desc(schema.scoringEvents.eventDate), desc(schema.scoringEvents.createdAt)],
    with: {
      eventResults: {
        with: {
          participant: true,
        },
      },
    },
  });
}

/**
 * Get incomplete scoring events for a sports season
 */
export async function getIncompleteScoringEvents(
  sportsSeasonId: string,
  providedDb?: ReturnType<typeof database>
) {
  const db = providedDb || database();

  return await db.query.scoringEvents.findMany({
    where: and(
      eq(schema.scoringEvents.sportsSeasonId, sportsSeasonId),
      eq(schema.scoringEvents.isComplete, false)
    ),
    orderBy: [desc(schema.scoringEvents.eventDate), desc(schema.scoringEvents.createdAt)],
  });
}

/**
 * Get qualifying events for a sports season
 */
export async function getQualifyingEvents(
  sportsSeasonId: string,
  providedDb?: ReturnType<typeof database>
) {
  const db = providedDb || database();

  return await db.query.scoringEvents.findMany({
    where: and(
      eq(schema.scoringEvents.sportsSeasonId, sportsSeasonId),
      eq(schema.scoringEvents.isQualifyingEvent, true)
    ),
    orderBy: [desc(schema.scoringEvents.eventDate), desc(schema.scoringEvents.createdAt)],
  });
}

/**
 * Update a scoring event
 */
export async function updateScoringEvent(
  eventId: string,
  data: UpdateScoringEventData,
  providedDb?: ReturnType<typeof database>
) {
  const db = providedDb || database();

  const updateData: any = { updatedAt: new Date() };

  if (data.name !== undefined) updateData.name = data.name;
  if (data.eventDate !== undefined) {
    updateData.eventDate = data.eventDate.toISOString().split('T')[0];
  }
  if (data.isComplete !== undefined) updateData.isComplete = data.isComplete;
  if (data.completedAt !== undefined) updateData.completedAt = data.completedAt;
  if (data.bracketTemplateId !== undefined) updateData.bracketTemplateId = data.bracketTemplateId;
  if (data.scoringStartsAtRound !== undefined) updateData.scoringStartsAtRound = data.scoringStartsAtRound;

  const [updated] = await db
    .update(schema.scoringEvents)
    .set(updateData)
    .where(eq(schema.scoringEvents.id, eventId))
    .returning();

  return updated;
}

/**
 * Mark a scoring event as complete
 */
export async function completeScoringEvent(
  eventId: string,
  providedDb?: ReturnType<typeof database>
) {
  const db = providedDb || database();

  return await updateScoringEvent(
    eventId,
    {
      isComplete: true,
      completedAt: new Date(),
    },
    db
  );
}

/**
 * Delete a scoring event.
 * For bracket events (playoff_game), also clears all participant results for the
 * sports season (placements are stored there with no FK back to the event) and
 * recalculates league standings.
 */
export async function deleteScoringEvent(
  eventId: string,
  providedDb?: ReturnType<typeof database>
) {
  const db = providedDb || database();

  const event = await db.query.scoringEvents.findFirst({
    where: eq(schema.scoringEvents.id, eventId),
  });

  if (!event) return;

  // For qualifying events: capture affected participant IDs before the cascade deletes
  // eventResults (which is how we know who had QP awarded from this event).
  let affectedParticipantIds: string[] = [];
  let wasQPProcessed = false;
  if (event.isQualifyingEvent) {
    const results = await db.query.eventResults.findMany({
      where: eq(schema.eventResults.scoringEventId, eventId),
    });
    affectedParticipantIds = results.map((r) => r.participantId);
    wasQPProcessed = results.some(
      (r) => r.qualifyingPointsAwarded && parseFloat(r.qualifyingPointsAwarded) > 0
    );
  }

  await db.transaction(async (tx) => {
    if (event.eventType === "playoff_game") {
      await tx
        .delete(schema.participantResults)
        .where(eq(schema.participantResults.sportsSeasonId, event.sportsSeasonId));
    }
    // Cascades: playoffMatches, eventResults, tournamentGroups/Members
    await tx.delete(schema.scoringEvents).where(eq(schema.scoringEvents.id, eventId));
  });

  if (event.eventType === "playoff_game") {
    await recalculateAffectedLeagues(event.sportsSeasonId, db);
  }

  if (event.isQualifyingEvent && affectedParticipantIds.length > 0) {
    // eventResults have been cascade-deleted; recalculate QP totals from remaining events
    for (const participantId of affectedParticipantIds) {
      await recalculateParticipantQP(participantId, event.sportsSeasonId, db);
    }

    // Decrement majorsCompleted if this event had already been processed
    if (wasQPProcessed) {
      const sportsSeason = await db.query.sportsSeasons.findFirst({
        where: eq(schema.sportsSeasons.id, event.sportsSeasonId),
      });
      if (sportsSeason && (sportsSeason.majorsCompleted ?? 0) > 0) {
        await db
          .update(schema.sportsSeasons)
          .set({ majorsCompleted: (sportsSeason.majorsCompleted ?? 1) - 1, updatedAt: new Date() })
          .where(eq(schema.sportsSeasons.id, event.sportsSeasonId));
      }
    }

    await recalculateAffectedLeagues(event.sportsSeasonId, db);
  }
}

/**
 * Check if all events for a sports season are complete
 */
export async function areAllEventsComplete(
  sportsSeasonId: string,
  providedDb?: ReturnType<typeof database>
): Promise<boolean> {
  const db = providedDb || database();

  const incompleteEvents = await getIncompleteScoringEvents(sportsSeasonId, db);
  return incompleteEvents.length === 0;
}

/**
 * Get upcoming (not yet complete) scoring events for a sports season,
 * ordered by eventDate ascending (soonest first).
 * Events without a date are included last.
 */
export async function getUpcomingScoringEvents(
  sportsSeasonId: string,
  limit = 5,
  providedDb?: ReturnType<typeof database>
) {
  const db = providedDb || database();

  return db.query.scoringEvents.findMany({
    where: and(
      eq(schema.scoringEvents.sportsSeasonId, sportsSeasonId),
      eq(schema.scoringEvents.isComplete, false)
    ),
    orderBy: [asc(schema.scoringEvents.eventDate), asc(schema.scoringEvents.createdAt)],
    limit,
  });
}

/**
 * Get the single next upcoming event for a sports season (for card display).
 */
export async function getNextScoringEvent(
  sportsSeasonId: string,
  providedDb?: ReturnType<typeof database>
) {
  const upcoming = await getUpcomingScoringEvents(sportsSeasonId, 1, providedDb);
  return upcoming[0] || null;
}

/**
 * Get recently completed scoring events for a sports season,
 * ordered by completedAt descending (most recent first).
 */
export async function getRecentCompletedEvents(
  sportsSeasonId: string,
  limit = 3,
  providedDb?: ReturnType<typeof database>
) {
  const db = providedDb || database();

  return db.query.scoringEvents.findMany({
    where: and(
      eq(schema.scoringEvents.sportsSeasonId, sportsSeasonId),
      eq(schema.scoringEvents.isComplete, true)
    ),
    orderBy: [desc(schema.scoringEvents.completedAt), desc(schema.scoringEvents.eventDate)],
    limit,
  });
}

/**
 * Bulk create scoring events for a sports season.
 * Returns created events in order.
 */
export async function bulkCreateScoringEvents(
  sportsSeasonId: string,
  events: Array<{ name: string; eventDate?: Date; eventType: EventType; isQualifyingEvent?: boolean }>,
  providedDb?: ReturnType<typeof database>
) {
  const db = providedDb || database();

  if (events.length === 0) return [];

  const rows = events.map((e) => ({
    sportsSeasonId,
    name: e.name,
    eventDate: e.eventDate ? e.eventDate.toISOString().split("T")[0] : undefined,
    eventType: e.eventType,
    isQualifyingEvent: e.isQualifyingEvent ?? false,
    isComplete: false,
  }));

  return db.insert(schema.scoringEvents).values(rows).returning();
}