import { auth } from "~/lib/auth.server";
import type { Route } from "./+types/$leagueId.sports-seasons.$sportsSeasonId.events.$eventId";
import {
  findLeagueById,
  isUserLeagueMember,
  isCommissioner,
  findTeamsBySeasonId,
  getUserDisplayName,
} from "~/models";
import { getDraftPicks } from "~/models/draft-pick";
import { getScoringEventById, getPrimaryEventForTournament, isReadOnlySibling } from "~/models/scoring-event";
import { findParticipantsBySportsSeasonId } from "~/models/season-participant";
import { getCs2StageResultsForEvent } from "~/models/cs2-major-stage";
import { findSeasonMatchesByScoringEventId } from "~/models/season-match";
import { getEventResults } from "~/models/event-result";
import { getBracketTemplate, getOrderedRoundsFromMatches } from "~/lib/bracket-templates";
import { findGroupsByEventId } from "~/models/tournament-group";
import { findMatchesByGroupIds, computeGroupStandings } from "~/models/group-stage-match";
import type { PlayoffMatch } from "~/models/playoff-match";
import { database } from "~/database/context";
import * as schema from "~/database/schema";
import { eq, and, inArray } from "drizzle-orm";

export async function loader({ params, request }: Route.LoaderArgs) {
  const session = await auth.api.getSession({ headers: request.headers });
  const userId = session?.user.id ?? null;
  const { leagueId, sportsSeasonId, eventId } = params;

  if (!userId) {
    throw new Response("You must be logged in to view this page", { status: 401 });
  }

  const league = await findLeagueById(leagueId);
  if (!league) throw new Response("League not found", { status: 404 });

  const [isUserCommissioner, isUserMember] = await Promise.all([
    isCommissioner(leagueId, userId),
    isUserLeagueMember(leagueId, userId),
  ]);
  if (!isUserCommissioner && !isUserMember) {
    throw new Response("You do not have access to this league", { status: 403 });
  }

  const db = database();

  const [scoringEvent, sportsSeason] = await Promise.all([
    getScoringEventById(eventId),
    db.query.sportsSeasons.findFirst({
      where: eq(schema.sportsSeasons.id, sportsSeasonId),
      with: { sport: true, seasonSports: { with: { season: true } } },
    }),
  ]);

  if (!scoringEvent) throw new Response("Event not found", { status: 404 });
  if (!sportsSeason) throw new Response("Sports season not found", { status: 404 });
  if (scoringEvent.sportsSeasonId !== sportsSeasonId) {
    throw new Response("Event does not belong to this sports season", { status: 404 });
  }

  const seasonSport = sportsSeason.seasonSports?.find(
    (ss) => ss.season.leagueId === leagueId
  );
  if (!seasonSport) {
    throw new Response("This sports season is not linked to this league", { status: 404 });
  }
  const season = seasonSport.season;

  // Build team ownership map
  const teams = await findTeamsBySeasonId(season.id);
  const draftPicks = await getDraftPicks(season.id);
  const ownerIds = [...new Set(teams.map((t) => t.ownerId).filter(Boolean))] as string[];
  const ownerUserRows = ownerIds.length > 0
    ? await db.query.users.findMany({
        where: inArray(schema.users.id, ownerIds),
        columns: { id: true, username: true, displayName: true },
      })
    : [];
  const ownerMap = new Map(ownerUserRows.map((u) => [u.id, getUserDisplayName(u) ?? "Unknown"]));
  const ownershipMap = new Map<string, { teamName: string; teamId: string; ownerName?: string }>();
  for (const pick of draftPicks) {
    const team = teams.find((t) => t.id === pick.teamId);
    if (team && pick.participantId) {
      ownershipMap.set(pick.participantId, {
        teamName: team.name,
        teamId: team.id,
        ownerName: team.ownerId ? ownerMap.get(team.ownerId) : undefined,
      });
    }
  }
  const teamOwnerships = Array.from(ownershipMap.entries()).map(([participantId, data]) => ({
    participantId,
    ...data,
  }));

  const userTeams = teams.filter((t) => t.ownerId === userId);
  const userTeamIds = new Set(userTeams.map((t) => t.id));
  const userParticipantIds = draftPicks
    .filter((p) => p.teamId && userTeamIds.has(p.teamId) && p.participantId)
    .map((p) => p.participantId as string);

  const simulatorType = sportsSeason.sport?.simulatorType ?? null;

  // Shared-major fan-out for DISPLAY: a tournament-linked, non-primary event has
  // no bracket/stage rows of its own — those live on the primary window. Read the
  // structure from the primary, then re-key this league's ownership overlay from
  // its own season_participant ids to the PRIMARY's season_participant ids (the
  // ids the bracket structure uses) via the shared canonical participant. QP/
  // results branches keep using this window's local rows and are untouched.
  let structureEventId = eventId;
  let structureBracketTemplateId = scoringEvent.bracketTemplateId;
  let bracketTeamOwnerships = teamOwnerships;
  let bracketUserParticipantIds = userParticipantIds;

  if (isReadOnlySibling(scoringEvent) && scoringEvent.tournamentId) {
    const primaryEvent = await getPrimaryEventForTournament(scoringEvent.tournamentId);
    if (primaryEvent && primaryEvent.id !== eventId) {
      structureEventId = primaryEvent.id;
      structureBracketTemplateId = primaryEvent.bracketTemplateId;

      const [siblingParticipants, primaryParticipants] = await Promise.all([
        findParticipantsBySportsSeasonId(sportsSeasonId),
        findParticipantsBySportsSeasonId(primaryEvent.sportsSeasonId),
      ]);
      // sibling season_participant id → canonical participant id
      const siblingSpToCanonical = new Map(
        siblingParticipants
          .filter((p) => p.participantId)
          .map((p) => [p.id, p.participantId as string])
      );
      // canonical participant id → primary season_participant id
      const canonicalToPrimarySp = new Map(
        primaryParticipants
          .filter((p) => p.participantId)
          .map((p) => [p.participantId as string, p.id])
      );
      const toPrimarySp = (siblingSpId: string): string | undefined => {
        const canonical = siblingSpToCanonical.get(siblingSpId);
        return canonical ? canonicalToPrimarySp.get(canonical) : undefined;
      };

      bracketTeamOwnerships = teamOwnerships.flatMap((o) => {
        const primarySpId = toPrimarySp(o.participantId);
        return primarySpId ? [{ ...o, participantId: primarySpId }] : [];
      });
      bracketUserParticipantIds = userParticipantIds.flatMap((id) => {
        const primarySpId = toPrimarySp(id);
        return primarySpId ? [primarySpId] : [];
      });
    }
  }

  type PlayoffMatchWithRelations = Omit<PlayoffMatch, "createdAt" | "updatedAt"> & {
    createdAt: string;
    updatedAt: string;
    participant1: { id: string; name: string } | null;
    participant2: { id: string; name: string } | null;
    winner: { id: string; name: string } | null;
    loser: { id: string; name: string } | null;
  };

  type RawGroupMatch = Awaited<ReturnType<typeof findMatchesByGroupIds>> extends Map<string, Array<infer T>> ? T : never;
  type GroupStandingData = {
    groupName: string;
    standings: ReturnType<typeof computeGroupStandings>;
    matches: Array<Omit<RawGroupMatch, "scheduledAt"> & { scheduledAt: string | null }>;
  };

  // CS2 Major — load Swiss stage data + bracket
  if (simulatorType === "cs2_major_qualifying_points") {
    const [cs2StageResults, seasonMatches, playoffMatchRows] = await Promise.all([
      getCs2StageResultsForEvent(structureEventId),
      findSeasonMatchesByScoringEventId(structureEventId),
      db.query.playoffMatches.findMany({
        where: eq(schema.playoffMatches.scoringEventId, structureEventId),
        with: { participant1: true, participant2: true, winner: true, loser: true },
      }),
    ]);

    const playoffMatches: PlayoffMatchWithRelations[] = playoffMatchRows.map((m) => ({
      ...m,
      createdAt: m.createdAt.toISOString(),
      updatedAt: m.updatedAt.toISOString(),
    }));
    const templateId = structureBracketTemplateId ?? undefined;
    const template = templateId ? getBracketTemplate(templateId) : undefined;
    const playoffRounds = getOrderedRoundsFromMatches(playoffMatches, template);

    return {
      kind: "cs2" as const,
      league,
      sportsSeason,
      scoringEvent,
      teamOwnerships: bracketTeamOwnerships,
      userParticipantIds: bracketUserParticipantIds,
      cs2StageResults,
      seasonMatches: seasonMatches.map((m) => ({
        ...m,
        scheduledAt: m.scheduledAt ? m.scheduledAt.toISOString() : null,
        startedAt: m.startedAt ? m.startedAt.toISOString() : null,
        completedAt: m.completedAt ? m.completedAt.toISOString() : null,
      })),
      playoffMatches,
      playoffRounds,
      bracketTemplateId: templateId ?? null,
    };
  }

  // Bracket events (tennis/golf bracket majors, soccer/UCL group+bracket)
  if (scoringEvent.eventType === "playoff_game") {
    const playoffMatchRows = await db.query.playoffMatches.findMany({
      where: eq(schema.playoffMatches.scoringEventId, structureEventId),
      with: { participant1: true, participant2: true, winner: true, loser: true },
    });
    const playoffMatches: PlayoffMatchWithRelations[] = playoffMatchRows.map((m) => ({
      ...m,
      createdAt: m.createdAt.toISOString(),
      updatedAt: m.updatedAt.toISOString(),
    }));
    const templateId = structureBracketTemplateId ?? undefined;
    const template = templateId ? getBracketTemplate(templateId) : undefined;
    const playoffRounds = getOrderedRoundsFromMatches(playoffMatches, template);

    let groupStandings: GroupStandingData[] = [];
    if (template?.groupStage) {
      const groups = await findGroupsByEventId(structureEventId);
      const matchesByGroupId = await findMatchesByGroupIds(groups.map((g) => g.id));
      groupStandings = groups.map((group) => {
        const groupMatches = matchesByGroupId.get(group.id) ?? [];
        const members = (group.members ?? [])
          .filter((m): m is typeof m & { participant: NonNullable<typeof m.participant> } => m.participant !== null)
          .map((m) => ({ participantId: m.participant.id, participantName: m.participant.name }));
        return {
          groupName: group.groupName,
          standings: computeGroupStandings(
            members,
            groupMatches.map((m) => ({
              participant1Id: m.participant1Id,
              participant2Id: m.participant2Id,
              participant1Score: m.participant1Score,
              participant2Score: m.participant2Score,
              isComplete: m.isComplete,
            }))
          ),
          matches: groupMatches.map((m) => ({
            ...m,
            scheduledAt: m.scheduledAt ? m.scheduledAt.toISOString() : null,
          })),
        };
      });
    }

    // Season participant results for scoring display
    const allResults = await db.query.seasonParticipantResults.findMany({
      where: and(
        eq(schema.seasonParticipantResults.sportsSeasonId, sportsSeasonId),
        eq(schema.seasonParticipantResults.finalPosition, 0)
      ),
      with: { participant: true },
    });
    const preEliminatedParticipants = allResults
      .filter((r): r is typeof r & { participant: NonNullable<typeof r.participant> } => r.participant !== null)
      .map((r) => ({ id: r.participant.id, name: r.participant.name }));

    return {
      kind: "bracket" as const,
      league,
      sportsSeason,
      scoringEvent,
      teamOwnerships: bracketTeamOwnerships,
      userParticipantIds: bracketUserParticipantIds,
      playoffMatches,
      playoffRounds,
      bracketTemplateId: templateId ?? null,
      groupStandings,
      preEliminatedParticipants,
    };
  }

  // QP major tournament / racing / other
  const eventResultRows = await getEventResults(eventId);
  const eventResults = eventResultRows
    .filter((r): r is typeof r & { placement: number } => r.placement !== null && !r.notParticipating)
    .map((r) => ({
      id: r.id,
      placement: r.placement,
      qualifyingPointsAwarded: r.qualifyingPointsAwarded,
      rawScore: r.rawScore,
      seasonParticipantId: r.seasonParticipantId,
      participantName: r.seasonParticipant?.name ?? null,
    }));

  return {
    kind: "results" as const,
    league,
    sportsSeason,
    scoringEvent,
    teamOwnerships,
    userParticipantIds,
    eventResults,
  };
}