import { database } from "~/database/context";
import { eq, inArray } from "drizzle-orm";
import * as schema from "~/database/schema";
import { findParticipantsBySportsSeasonId, updateParticipant } from "~/models/season-participant";
import { upsertRegularSeasonStandings } from "~/models/regular-season-standings";
import { upsertPendingStandingsMappings } from "~/models/pending-standings-mappings";
import { upsertSeasonResultsBulk } from "~/models/participant-season-result";
import { findMatchingTeamName } from "~/lib/normalize-team-name";
import { NhlStandingsAdapter } from "./nhl";
import { NbaStandingsAdapter } from "./nba";
import { AflStandingsAdapter } from "./afl";
import { MlbStandingsAdapter } from "./mlb";
import { WnbaStandingsAdapter } from "./wnba";
import { EplStandingsAdapter } from "./epl";
import { MlsStandingsAdapter } from "./mls";
import { F1StandingsAdapter, IndyCarStandingsAdapter } from "./f1";
import type { StandingsSyncAdapter, SyncResult, UnmatchedTeam } from "./types";

function getAdapter(simulatorType: string): StandingsSyncAdapter {
  switch (simulatorType) {
    case "nba_bracket":
      return new NbaStandingsAdapter();
    case "nhl_bracket":
      return new NhlStandingsAdapter();
    case "afl_bracket":
      return new AflStandingsAdapter();
    case "epl_standings":
      return new EplStandingsAdapter();
    case "mls_bracket":
      return new MlsStandingsAdapter();
    case "mlb_bracket":
      return new MlbStandingsAdapter();
    case "wnba_bracket":
      return new WnbaStandingsAdapter();
    case "f1_standings":
      return new F1StandingsAdapter();
    case "indycar_standings":
      return new IndyCarStandingsAdapter();
    default:
      throw new Error(
        `No standings sync adapter available for simulator type "${simulatorType}". ` +
          "NBA, NHL, AFL, MLB, WNBA, EPL, MLS, F1, and IndyCar are currently supported."
      );
  }
}

/**
 * Sync current standings from the appropriate external API for a sports season.
 * Matches API team names to participants by name and bulk-upserts the results.
 *
 * For season_standings sports (F1, IndyCar), upserts into participantSeasonResults.
 * For all other sports, upserts into regularSeasonStandings.
 *
 * Returns the count of synced entries and any API names that couldn't be matched.
 */
export async function syncStandings(sportsSeasonId: string): Promise<SyncResult> {
  const db = database();

  // Load sports season with sport relation
  const sportsSeason = await db.query.sportsSeasons.findFirst({
    where: eq(schema.sportsSeasons.id, sportsSeasonId),
    with: { sport: true },
  });

  if (!sportsSeason) {
    throw new Error(`Sports season ${sportsSeasonId} not found`);
  }

  const simulatorType = sportsSeason.sport?.simulatorType;
  if (!simulatorType) {
    const sportName = sportsSeason.sport?.name ?? "(no sport linked)";
    throw new Error(`Sport "${sportName}" has no simulator type configured`);
  }

  const isSeasonStandings = sportsSeason.scoringPattern === "season_standings";

  const adapter = getAdapter(simulatorType);
  const fetchedRecords = await adapter.fetchStandings();

  // Load all participants for this season
  const participants = await findParticipantsBySportsSeasonId(sportsSeasonId);
  const participantNames = participants.map((p) => p.name);
  const participantByName = new Map(participants.map((p) => [p.name, p]));
  const participantByExternalId = new Map(
    participants.filter((p) => p.externalId).map((p) => [p.externalId ?? "", p])
  );

  type RegularUpsertRow = Parameters<typeof upsertRegularSeasonStandings>[0][number];
  type SeasonResultRow = Parameters<typeof upsertSeasonResultsBulk>[0][number];

  const toUpsertRegular: RegularUpsertRow[] = [];
  const toUpsertSeason: SeasonResultRow[] = [];
  const matchedParticipantIds: string[] = [];
  const unmatchedRecords: typeof fetchedRecords = [];

  for (const record of fetchedRecords) {
    let participant = participantByExternalId.get(record.externalTeamId) ?? null;

    if (!participant) {
      const matchedName = findMatchingTeamName(record.teamName, participantNames);
      if (matchedName) {
        participant = participantByName.get(matchedName) ?? null;
        if (participant && !participant.externalId) {
          await updateParticipant(participant.id, { externalId: record.externalTeamId });
        }
      }
    }

    if (!participant) {
      unmatchedRecords.push(record);
      continue;
    }

    matchedParticipantIds.push(participant.id);

    if (isSeasonStandings) {
      toUpsertSeason.push({
        participantId: participant.id,
        sportsSeasonId,
        currentPoints: record.currentPoints ?? 0,
        currentPosition: record.leagueRank,
      });
    } else {
      toUpsertRegular.push({
        participantId: participant.id,
        sportsSeasonId,
        wins: record.wins,
        losses: record.losses,
        otLosses: record.otLosses ?? null,
        ties: record.ties ?? null,
        tablePoints: record.tablePoints ?? null,
        goalsFor: record.goalsFor ?? null,
        goalsAgainst: record.goalsAgainst ?? null,
        goalDifference: record.goalDifference ?? null,
        winPct: record.winPct,
        gamesPlayed: record.gamesPlayed,
        gamesBack: record.gamesBack ?? null,
        conference: record.conference ?? null,
        division: record.division ?? null,
        conferenceRank: record.conferenceRank ?? null,
        divisionRank: record.divisionRank ?? null,
        leagueRank: record.leagueRank,
        streak: record.streak ?? null,
        lastTen: record.lastTen ?? null,
        homeRecord: record.homeRecord ?? null,
        awayRecord: record.awayRecord ?? null,
        externalTeamId: record.externalTeamId,
        srs: record.srs ?? null,
        syncedAt: new Date(),
      });
    }
  }

  let changed = false;

  if (isSeasonStandings && toUpsertSeason.length > 0) {
    const currentRows = await db
      .select({
        participantId: schema.participantSeasonResults.participantId,
        currentPoints: schema.participantSeasonResults.currentPoints,
        currentPosition: schema.participantSeasonResults.currentPosition,
      })
      .from(schema.participantSeasonResults)
      .where(inArray(schema.participantSeasonResults.participantId, matchedParticipantIds));

    const currentByParticipant = new Map(currentRows.map((r) => [r.participantId, r]));

    changed = toUpsertSeason.some((row) => {
      const current = currentByParticipant.get(row.participantId);
      if (!current) return true;
      return (
        current.currentPosition !== row.currentPosition ||
        parseFloat(current.currentPoints ?? "0") !== (row.currentPoints ?? 0)
      );
    });

    await upsertSeasonResultsBulk(toUpsertSeason);

    if (changed) {
      await db
        .update(schema.sportsSeasons)
        .set({ standingsLastChangedAt: new Date() })
        .where(eq(schema.sportsSeasons.id, sportsSeasonId));
    }
  } else if (!isSeasonStandings && toUpsertRegular.length > 0) {
    const currentRows = await db
      .select({
        participantId: schema.regularSeasonStandings.participantId,
        gamesPlayed: schema.regularSeasonStandings.gamesPlayed,
        leagueRank: schema.regularSeasonStandings.leagueRank,
      })
      .from(schema.regularSeasonStandings)
      .where(inArray(schema.regularSeasonStandings.participantId, matchedParticipantIds));

    const currentByParticipant = new Map(currentRows.map((r) => [r.participantId, r]));

    changed = toUpsertRegular.some((row) => {
      const current = currentByParticipant.get(row.participantId);
      if (!current) return true;
      return current.gamesPlayed !== row.gamesPlayed || current.leagueRank !== row.leagueRank;
    });

    await upsertRegularSeasonStandings(toUpsertRegular);

    if (changed) {
      await db
        .update(schema.sportsSeasons)
        .set({ standingsLastChangedAt: new Date() })
        .where(eq(schema.sportsSeasons.id, sportsSeasonId));
    }
  }

  if (unmatchedRecords.length > 0) {
    await upsertPendingStandingsMappings(sportsSeasonId, unmatchedRecords);
  }

  const unmatched: UnmatchedTeam[] = unmatchedRecords.map((r) => ({
    teamName: r.teamName,
    externalTeamId: r.externalTeamId,
  }));

  const synced = isSeasonStandings ? toUpsertSeason.length : toUpsertRegular.length;
  return { synced, unmatched, changed };
}