import type {
  Match,
  MatchGame,
  Seeding,
  Stage,
  GroupType,
} from "brackets-model";
import { Status } from "brackets-model";
import type { DeepPartial, ParticipantSlot, Side } from "../types";
import type { SetNextOpponent } from "../helpers";
import { ordering } from "../ordering";
import { Create } from "../create";
import { BaseGetter } from "./getter";
import { Get } from "../get";
import * as helpers from "../helpers";

export class BaseUpdater extends BaseGetter {
  /**
   * Updates or resets the seeding of a stage.
   *
   * @param stageId ID of the stage.
   * @param seeding A new seeding or `null` to reset the existing seeding.
   */
  protected updateSeeding(stageId: number, seeding: Seeding | null): void {
    const stage = this.storage.select("stage", stageId);
    if (!stage) throw Error("Stage not found.");

    const create = new Create(this.storage, {
      name: stage.name,
      tournamentId: stage.tournament_id,
      type: stage.type,
      settings: stage.settings,
      seeding: seeding || undefined,
    });

    create.setExisting(stageId, false);

    const method = BaseGetter.getSeedingOrdering(stage.type, create);
    const slots = create.getSlots();

    const matches = this.getSeedingMatches(stage.id, stage.type);
    if (!matches)
      throw Error("Error getting matches associated to the seeding.");

    const ordered = ordering[method](slots);
    BaseUpdater.assertCanUpdateSeeding(matches, ordered);

    create.run();
  }

  /**
   * Confirms the current seeding of a stage.
   *
   * @param stageId ID of the stage.
   */
  protected confirmCurrentSeeding(stageId: number): void {
    const stage = this.storage.select("stage", stageId);
    if (!stage) throw Error("Stage not found.");

    const get = new Get(this.storage);
    const currentSeeding = get.seeding(stageId);
    const newSeeding = helpers.convertSlotsToSeeding(
      currentSeeding.map(helpers.convertTBDtoBYE)
    );

    const create = new Create(this.storage, {
      name: stage.name,
      tournamentId: stage.tournament_id,
      type: stage.type,
      settings: stage.settings,
      seeding: newSeeding,
    });

    create.setExisting(stageId, true);

    create.run();
  }

  /**
   * Updates a parent match based on its child games.
   *
   * @param parentId ID of the parent match.
   * @param inRoundRobin Indicates whether the parent match is in a round-robin stage.
   */
  protected updateParentMatch(parentId: number, inRoundRobin: boolean): void {
    const storedParent = this.storage.select("match", parentId);
    if (!storedParent) throw Error("Parent not found.");

    const games = this.storage.select("match_game", {
      parent_id: parentId,
    });
    if (!games) throw Error("No match games.");

    const parentScores = helpers.getChildGamesResults(games);
    const parent = helpers.getParentMatchResults(storedParent, parentScores);

    helpers.setParentMatchCompleted(
      parent,
      storedParent.child_count,
      inRoundRobin
    );

    this.updateMatch(storedParent, parent, true);
  }

  /**
   * Throws an error if a match is locked and the new seeding will change this match's participants.
   *
   * @param matches The matches stored in the database.
   * @param slots The slots to check from the new seeding.
   */
  protected static assertCanUpdateSeeding(
    matches: Match[],
    slots: ParticipantSlot[]
  ): void {
    let index = 0;

    for (const match of matches) {
      const opponent1 = slots[index++];
      const opponent2 = slots[index++];

      const locked = helpers.isMatchParticipantLocked(match);
      if (!locked) continue;

      if (
        match.opponent1?.id !== opponent1?.id ||
        match.opponent2?.id !== opponent2?.id
      )
        throw Error("A match is locked.");
    }
  }

  /**
   * Updates the matches related (previous and next) to a match.
   *
   * @param match A match.
   * @param updatePrevious Whether to update the previous matches.
   * @param updateNext Whether to update the next matches.
   */
  protected updateRelatedMatches(
    match: Match,
    updatePrevious: boolean,
    updateNext: boolean
  ): void {
    const { roundNumber, roundCount } = this.getRoundPositionalInfo(
      match.round_id
    );

    const stage = this.storage.select("stage", match.stage_id);
    if (!stage) throw Error("Stage not found.");

    const group = this.storage.select("group", match.group_id);
    if (!group) throw Error("Group not found.");

    const matchLocation = helpers.getMatchLocation(stage.type, group.number);

    updatePrevious &&
      this.updatePrevious(match, matchLocation, stage, roundNumber);
    updateNext &&
      this.updateNext(match, matchLocation, stage, roundNumber, roundCount);
  }

  /**
   * Updates a match based on a partial match.
   *
   * @param stored A reference to what will be updated in the storage.
   * @param match Input of the update.
   * @param force Whether to force update locked matches.
   */
  protected updateMatch(
    stored: Match,
    match: DeepPartial<Match>,
    force?: boolean
  ): void {
    if (!force && helpers.isMatchUpdateLocked(stored))
      throw Error("The match is locked.");

    const stage = this.storage.select("stage", stored.stage_id);
    if (!stage) throw Error("Stage not found.");

    const inRoundRobin = helpers.isRoundRobin(stage);

    const { statusChanged, resultChanged } = helpers.setMatchResults(
      stored,
      match,
      inRoundRobin
    );
    this.applyMatchUpdate(stored);

    // Don't update related matches if it's a simple score update.
    if (!statusChanged && !resultChanged) return;

    if (!helpers.isRoundRobin(stage))
      this.updateRelatedMatches(stored, statusChanged, resultChanged);
  }

  /**
   * Updates a match game based on a partial match game.
   *
   * @param stored A reference to what will be updated in the storage.
   * @param game Input of the update.
   */
  protected updateMatchGame(
    stored: MatchGame,
    game: DeepPartial<MatchGame>
  ): void {
    if (helpers.isMatchUpdateLocked(stored))
      throw Error("The match game is locked.");

    const stage = this.storage.select("stage", stored.stage_id);
    if (!stage) throw Error("Stage not found.");

    const inRoundRobin = helpers.isRoundRobin(stage);

    helpers.setMatchResults(stored, game, inRoundRobin);

    if (!this.storage.update("match_game", stored.id, stored))
      throw Error("Could not update the match game.");

    this.updateParentMatch(stored.parent_id, inRoundRobin);
  }

  /**
   * Updates the opponents and status of a match and its child games.
   *
   * @param match A match.
   */
  protected applyMatchUpdate(match: Match): void {
    if (!this.storage.update("match", match.id, match))
      throw Error("Could not update the match.");

    if (match.child_count === 0) return;

    const updatedMatchGame: Partial<MatchGame> = {
      opponent1: helpers.toResult(match.opponent1),
      opponent2: helpers.toResult(match.opponent2),
    };

    // Only sync the child games' status with their parent's status when changing the parent match participants
    // (Locked, Waiting, Ready) or when archiving the parent match.
    if (match.status <= Status.Ready || match.status === Status.Archived)
      updatedMatchGame.status = match.status;

    if (
      !this.storage.update(
        "match_game",
        { parent_id: match.id },
        updatedMatchGame
      )
    )
      throw Error("Could not update the match game.");
  }

  /**
   * Updates the match(es) leading to the current match based on this match results.
   *
   * @param match Input of the update.
   * @param matchLocation Location of the current match.
   * @param stage The parent stage.
   * @param roundNumber Number of the round.
   */
  protected updatePrevious(
    match: Match,
    matchLocation: GroupType,
    stage: Stage,
    roundNumber: number
  ): void {
    const previousMatches = this.getPreviousMatches(
      match,
      matchLocation,
      stage,
      roundNumber
    );
    if (previousMatches.length === 0) return;

    if (match.status >= Status.Running) this.archiveMatches(previousMatches);
    else this.resetMatchesStatus(previousMatches);
  }

  /**
   * Sets the status of a list of matches to archived.
   *
   * @param matches The matches to update.
   */
  protected archiveMatches(matches: Match[]): void {
    for (const match of matches) {
      match.status = Status.Archived;
      this.applyMatchUpdate(match);
    }
  }

  /**
   * Resets the status of a list of matches to what it should currently be.
   *
   * @param matches The matches to update.
   */
  protected resetMatchesStatus(matches: Match[]): void {
    for (const match of matches) {
      match.status = helpers.getMatchStatus(match);
      this.applyMatchUpdate(match);
    }
  }

  /**
   * Updates the match(es) following the current match based on this match results.
   *
   * @param match Input of the update.
   * @param matchLocation Location of the current match.
   * @param stage The parent stage.
   * @param roundNumber Number of the round.
   * @param roundCount Count of rounds.
   */
  protected updateNext(
    match: Match,
    matchLocation: GroupType,
    stage: Stage,
    roundNumber: number,
    roundCount: number
  ): void {
    const nextMatches = this.getNextMatches(
      match,
      matchLocation,
      stage,
      roundNumber,
      roundCount
    );
    if (nextMatches.length === 0) return;

    const winnerSide = helpers.getMatchResult(match);
    const actualRoundNumber =
      stage.settings.skipFirstRound && matchLocation === "winner_bracket"
        ? roundNumber + 1
        : roundNumber;

    if (winnerSide)
      this.applyToNextMatches(
        helpers.setNextOpponent,
        match,
        matchLocation,
        actualRoundNumber,
        roundCount,
        nextMatches,
        winnerSide
      );
    else
      this.applyToNextMatches(
        helpers.resetNextOpponent,
        match,
        matchLocation,
        actualRoundNumber,
        roundCount,
        nextMatches
      );
  }

  /**
   * Applies a SetNextOpponent function to matches following the current match.
   *
   * @param setNextOpponent The SetNextOpponent function.
   * @param match The current match.
   * @param matchLocation Location of the current match.
   * @param roundNumber Number of the current round.
   * @param roundCount Count of rounds.
   * @param nextMatches The matches following the current match.
   * @param winnerSide Side of the winner in the current match.
   */
  protected applyToNextMatches(
    setNextOpponent: SetNextOpponent,
    match: Match,
    matchLocation: GroupType,
    roundNumber: number,
    roundCount: number,
    nextMatches: (Match | null)[],
    winnerSide?: Side
  ): void {
    if (matchLocation === "final_group") {
      if (!nextMatches[0]) throw Error("First next match is null.");
      setNextOpponent(nextMatches[0], "opponent1", match, "opponent1");
      setNextOpponent(nextMatches[0], "opponent2", match, "opponent2");
      this.applyMatchUpdate(nextMatches[0]);
      return;
    }

    const nextSide = helpers.getNextSide(
      match.number,
      roundNumber,
      roundCount,
      matchLocation
    );

    if (nextMatches[0]) {
      setNextOpponent(nextMatches[0], nextSide, match, winnerSide);
      this.propagateByeWinners(nextMatches[0]);
    }

    if (nextMatches.length !== 2) return;
    if (!nextMatches[1]) throw Error("Second next match is null.");

    // The second match is either the consolation final (single elimination) or a loser bracket match (double elimination).

    if (matchLocation === "single_bracket") {
      setNextOpponent(
        nextMatches[1],
        nextSide,
        match,
        winnerSide && helpers.getOtherSide(winnerSide)
      );
      this.applyMatchUpdate(nextMatches[1]);
    } else {
      const nextSideLB = helpers.getNextSideLoserBracket(
        match.number,
        nextMatches[1],
        roundNumber
      );
      setNextOpponent(
        nextMatches[1],
        nextSideLB,
        match,
        winnerSide && helpers.getOtherSide(winnerSide)
      );
      this.propagateByeWinners(nextMatches[1]);
    }
  }

  /**
   * Propagates winner against BYEs in related matches.
   *
   * @param match The current match.
   */
  protected propagateByeWinners(match: Match): void {
    helpers.setMatchResults(match, match, false); // BYE propagation is only in non round-robin stages.
    this.applyMatchUpdate(match);

    if (helpers.hasBye(match)) this.updateRelatedMatches(match, true, true);
  }
}