brackt/app/routes/admin.sports-seasons.$id.events.$eventId.bracket.server.ts

import type { Route } from "./+types/admin.sports-seasons.$id.events.$eventId.bracket";
import { redirect } from "react-router";
import { findSportsSeasonById } from "~/models/sports-season";
import { findParticipantsBySportsSeasonId } from "~/models/participant";
import { getScoringEventById, updateScoringEvent } from "~/models/scoring-event";
import {
  findPlayoffMatchesByEventId,
  generateBracketFromTemplate,
  setMatchWinner,
  advanceWinnerTemplate,
  findPlayoffMatchById,
  assignParticipantsToKnockout,
} from "~/models/playoff-match";
import { processPlayoffEvent } from "~/models/scoring-calculator";
import { getBracketTemplate } from "~/lib/bracket-templates";
import {
  createGroupsForEvent,
  addMembersToGroup,
  findGroupsByEventId,
  toggleMemberEliminated,
  getAdvancingParticipantIds,
  getEliminatedParticipantIds,
} from "~/models/tournament-group";
import { database } from "~/database/context";
import * as schema from "~/database/schema";
import { eq, and } from "drizzle-orm";

export async function loader({ params }: Route.LoaderArgs) {
  const sportsSeason = await findSportsSeasonById(params.id);

  if (!sportsSeason) {
    throw new Response("Sports season not found", { status: 404 });
  }

  const event = await getScoringEventById(params.eventId);

  if (!event) {
    throw new Response("Event not found", { status: 404 });
  }

  if (event.eventType !== "playoff_game") {
    throw new Response("This event is not a playoff event", { status: 400 });
  }

  const participants = await findParticipantsBySportsSeasonId(params.id);
  const matches = await findPlayoffMatchesByEventId(params.eventId);

  // Fetch tournament groups if this event has a group-stage template
  const tournamentGroups = await findGroupsByEventId(params.eventId);

  // The matches already include participant relations from the model query
  return {
    sportsSeason: sportsSeason as typeof sportsSeason & {
      sport: { id: string; name: string; type: string; slug: string };
    },
    event,
    participants,
    matches: matches as Array<typeof matches[0] & {
      participant1: { id: string; name: string } | null;
      participant2: { id: string; name: string } | null;
      winner: { id: string; name: string } | null;
      loser: { id: string; name: string } | null;
    }>,
    tournamentGroups,
  };
}

export async function action({ request, params }: Route.ActionArgs) {
  const formData = await request.formData();
  const intent = formData.get("intent");

  if (intent === "generate-bracket") {
    const templateId = formData.get("templateId");

    if (typeof templateId !== "string" || !templateId) {
      return { error: "Template ID is required" };
    }

    const template = getBracketTemplate(templateId);
    if (!template) {
      return { error: "Invalid bracket template" };
    }

    const participantIds: string[] = [];

    for (let i = 0; i < template.totalTeams; i++) {
      const participantId = formData.get(`participant${i}`);
      if (typeof participantId !== "string" || !participantId) {
        return { error: `Participant ${i + 1} is required` };
      }
      participantIds.push(participantId);
    }

    // Check for duplicates
    const uniqueParticipants = new Set(participantIds);
    if (uniqueParticipants.size !== participantIds.length) {
      return { error: "Each participant can only be selected once" };
    }

    try {
      await generateBracketFromTemplate(params.eventId, templateId, participantIds);

      // PHASE 5.3: Mark participants NOT in the bracket as eliminated
      const event = await getScoringEventById(params.eventId);
      if (event) {
        // Get all participants in the sports season
        const allParticipants = await findParticipantsBySportsSeasonId(params.id);

        // Create a set of participants in the bracket for fast lookup
        const participantsInBracket = new Set(participantIds);

        // Mark participants NOT in the bracket as eliminated
        const { setParticipantResult } = await import("~/models/participant-result");
        for (const participant of allParticipants) {
          if (!participantsInBracket.has(participant.id)) {
            await setParticipantResult(
              participant.id,
              event.sportsSeasonId,
              0 // 0 = didn't make playoffs, eliminated
            );
          }
        }

        console.log(`[BracketGeneration] Marked ${allParticipants.length - participantIds.length} participants as eliminated`);
      }

      // Update the event to store the template ID and scoring start round
      await updateScoringEvent(params.eventId, {
        bracketTemplateId: templateId,
        scoringStartsAtRound: template.scoringStartsAtRound,
      });

      return { success: "Bracket generated successfully" };
    } catch (error) {
      console.error("Error generating bracket:", error);
      return {
        error:
          error instanceof Error
            ? error.message
            : "Failed to generate bracket",
      };
    }
  }

  if (intent === "set-winner") {
    const matchId = formData.get("matchId");
    const winnerId = formData.get("winnerId");

    if (typeof matchId !== "string" || !matchId) {
      return { error: "Match ID is required" };
    }

    if (typeof winnerId !== "string" || !winnerId) {
      return { error: "Winner ID is required" };
    }

    try {
      const match = await findPlayoffMatchById(matchId);
      if (!match) {
        return { error: "Match not found" };
      }

      // Get the event to determine the template
      const event = await getScoringEventById(match.scoringEventId);
      if (!event) {
        return { error: "Event not found" };
      }

      // Determine loser
      const loserId =
        match.participant1Id === winnerId
          ? match.participant2Id
          : match.participant1Id;

      if (!loserId) {
        return { error: "Could not determine loser" };
      }

      // Set the winner
      await setMatchWinner(matchId, winnerId, loserId);

      // Try to advance the winner to the next round using template
      if (event.bracketTemplateId) {
        const template = getBracketTemplate(event.bracketTemplateId);
        if (template) {
          try {
            await advanceWinnerTemplate(matchId, winnerId, template);
          } catch (error) {
            // Only ignore "already filled" errors, re-throw unexpected errors
            if (
              error instanceof Error &&
              error.message.includes("already filled")
            ) {
              console.warn("Match already filled, skipping advancement");
            } else {
              throw error; // Re-throw unexpected errors
            }
          }
        }
      }

      return { success: "Winner set successfully" };
    } catch (error) {
      console.error("Error setting winner:", error);
      return {
        error:
          error instanceof Error ? error.message : "Failed to set winner",
      };
    }
  }

  if (intent === "set-round-winners") {
    const round = formData.get("round");

    if (typeof round !== "string" || !round) {
      return { error: "Round is required" };
    }

    try {
      // Get all winner assignments from form data
      const winnerAssignments: Array<{ matchId: string; winnerId: string }> = [];

      for (const [key, value] of formData.entries()) {
        if (key.startsWith("winner-") && typeof value === "string") {
          const matchId = key.replace("winner-", "");
          winnerAssignments.push({ matchId, winnerId: value });
        }
      }

      if (winnerAssignments.length === 0) {
        return { error: "No winners selected" };
      }

      // Get the event to determine the template
      const event = await getScoringEventById(params.eventId);
      if (!event) {
        return { error: "Event not found" };
      }

      const template = event.bracketTemplateId ? getBracketTemplate(event.bracketTemplateId) : null;

      // Process each winner assignment
      let successCount = 0;
      const errors: string[] = [];

      for (const { matchId, winnerId } of winnerAssignments) {
        try {
          const match = await findPlayoffMatchById(matchId);
          if (!match) {
            errors.push(`Match ${matchId} not found`);
            continue;
          }

          // Determine loser
          const loserId =
            match.participant1Id === winnerId
              ? match.participant2Id
              : match.participant1Id;

          if (!loserId) {
            errors.push(`Could not determine loser for match ${match.matchNumber}`);
            continue;
          }

          // Set the winner
          await setMatchWinner(matchId, winnerId, loserId);

          // Try to advance the winner to the next round using template
          if (template) {
            try {
              await advanceWinnerTemplate(matchId, winnerId, template);
            } catch (error) {
              // Only ignore "already filled" errors
              if (
                error instanceof Error &&
                error.message.includes("already filled")
              ) {
                console.warn("Match already filled, skipping advancement");
              } else {
                throw error;
              }
            }
          }

          successCount++;
        } catch (error) {
          console.error(`Error setting winner for match ${matchId}:`, error);
          errors.push(
            `Match ${matchId}: ${error instanceof Error ? error.message : "Unknown error"}`
          );
        }
      }

      if (errors.length > 0 && successCount === 0) {
        return { error: `Failed to set winners: ${errors.join(", ")}` };
      }

      if (errors.length > 0) {
        return {
          success: `Set ${successCount} winner(s) successfully`,
          error: `Some errors occurred: ${errors.join(", ")}`,
        };
      }

      return { success: `Successfully set ${successCount} winner(s) for ${round}` };
    } catch (error) {
      console.error("Error setting round winners:", error);
      return {
        error:
          error instanceof Error ? error.message : "Failed to set winners",
      };
    }
  }

  if (intent === "complete-round") {
    const round = formData.get("round");

    if (typeof round !== "string" || !round) {
      return { error: "Round is required" };
    }

    try {
      // Get the event and update playoffRound to the completed round
      const event = await getScoringEventById(params.eventId);
      if (!event) {
        return { error: "Event not found" };
      }

      // Verify all matches in this round are complete
      const matches = await findPlayoffMatchesByEventId(params.eventId);

      // Validate that the round exists in this event's matches
      const roundMatches = matches.filter((m) => m.round === round);
      if (roundMatches.length === 0) {
        return { error: `Round "${round}" not found in this bracket` };
      }

      const allComplete = roundMatches.every((m) => m.isComplete);
      if (!allComplete) {
        return { error: `Not all matches in ${round} are complete` };
      }

      // Validate round order: ensure previous rounds are complete
      const { findParticipantResultsBySportsSeasonId } = await import(
        "~/models/participant-result"
      );
      const existingResults = await findParticipantResultsBySportsSeasonId(
        params.id
      );

      if (round === "Finals") {
        // Finals requires Semifinals to be complete (3rd/4th place results exist)
        const hasSemifinalResults = existingResults.some(
          (r) => r.finalPosition === 3 || r.finalPosition === 4
        );
        if (!hasSemifinalResults) {
          return {
            error:
              "Semifinals must be completed before Finals (no 3rd/4th place results found)",
          };
        }
      } else if (round === "Semifinals") {
        // Semifinals requires Quarterfinals to be complete if QF matches exist
        const hasQuarterfinals = matches.some((m) => m.round === "Quarterfinals");
        if (hasQuarterfinals) {
          const hasQuarterfinalsResults = existingResults.some(
            (r) =>
              r.finalPosition === 5 ||
              r.finalPosition === 6 ||
              r.finalPosition === 7 ||
              r.finalPosition === 8
          );
          if (!hasQuarterfinalsResults) {
            return {
              error:
                "Quarterfinals must be completed before Semifinals (no 5th-8th place results found)",
            };
          }
        }
      }

      // Get the sports season to find a fantasy season for scoring rules
      const sportsSeason = await findSportsSeasonById(params.id);
      if (!sportsSeason) {
        return { error: "Sports season not found" };
      }

      // Process the playoff event to calculate placements
      // TODO Phase 2.7: Refactor processPlayoffEvent to use template system
      // For now, we still need to set playoffRound for the old scoring logic
      // even though we removed it from the create event UI
      const db = database();
      await db
        .update(schema.scoringEvents)
        .set({ playoffRound: round, updatedAt: new Date() })
        .where(eq(schema.scoringEvents.id, params.eventId));

      // Get a fantasy season ID for scoring calculation
      const { findSeasonSportsBySportsSeasonId } = await import(
        "~/models/season-sport"
      );
      const seasonSports = await findSeasonSportsBySportsSeasonId(params.id);
      if (seasonSports.length === 0) {
        return {
          error: "No fantasy seasons found for this sports season",
        };
      }

      // Process playoff event to update participant results
      await processPlayoffEvent(params.eventId);

      return {
        success: `${round} completed and placements calculated successfully`,
      };
    } catch (error) {
      console.error("Error completing round:", error);
      return {
        error:
          error instanceof Error ? error.message : "Failed to complete round",
      };
    }
  }

  if (intent === "reprocess-eliminations") {
    try {
      // Get the event
      const event = await getScoringEventById(params.eventId);
      if (!event) {
        return { error: "Event not found" };
      }

      // Get all matches in the bracket
      const matches = await findPlayoffMatchesByEventId(params.eventId);
      if (matches.length === 0) {
        return { error: "No bracket exists for this event" };
      }

      // Get all participants in the sports season
      const allParticipants = await findParticipantsBySportsSeasonId(params.id);

      // Collect all participant IDs that appear in ANY match
      const participantsInBracket = new Set<string>();
      for (const match of matches) {
        if (match.participant1Id) participantsInBracket.add(match.participant1Id);
        if (match.participant2Id) participantsInBracket.add(match.participant2Id);
      }

      // Mark participants NOT in the bracket as eliminated
      const { setParticipantResult } = await import("~/models/participant-result");
      let eliminatedCount = 0;

      for (const participant of allParticipants) {
        if (!participantsInBracket.has(participant.id)) {
          await setParticipantResult(
            participant.id,
            event.sportsSeasonId,
            0 // 0 = didn't make playoffs, eliminated
          );
          eliminatedCount++;
        }
      }

      console.log(`[ReprocessEliminations] Marked ${eliminatedCount} participants as eliminated`);

      return {
        success: `Successfully marked ${eliminatedCount} participant(s) as eliminated`,
      };
    } catch (error) {
      console.error("Error reprocessing eliminations:", error);
      return {
        error:
          error instanceof Error ? error.message : "Failed to reprocess eliminations",
      };
    }
  }

  if (intent === "finalize-bracket") {
    try {
      // Get the event
      const event = await getScoringEventById(params.eventId);
      if (!event) {
        return { error: "Event not found" };
      }

      // Get all matches
      const matches = await findPlayoffMatchesByEventId(params.eventId);
      if (matches.length === 0) {
        return { error: "No bracket exists for this event" };
      }

      // Get template to determine round order
      const template = event.bracketTemplateId ? getBracketTemplate(event.bracketTemplateId) : null;
      if (!template) {
        return { error: "Bracket template not found" };
      }

      // Verify ALL matches are complete
      const incompleteMatches = matches.filter((m) => !m.isComplete);
      if (incompleteMatches.length > 0) {
        return {
          error: `Cannot finalize: ${incompleteMatches.length} match(es) still incomplete`,
        };
      }

      // Get all participants in this sports season
      const { findParticipantsBySportsSeasonId } = await import("~/models/participant");
      const allParticipants = await findParticipantsBySportsSeasonId(params.id);

      // Get participants in matches
      const participantsInMatches = new Set(
        matches.flatMap((m) => [m.participant1Id, m.participant2Id].filter(Boolean))
      );

      // Process all rounds in order
      const db = database();
      for (const round of template.rounds) {
        const roundMatches = matches.filter((m) => m.round === round.name);
        if (roundMatches.length === 0) continue;

        // Set playoffRound and process this round
        await db
          .update(schema.scoringEvents)
          .set({ playoffRound: round.name, updatedAt: new Date() })
          .where(eq(schema.scoringEvents.id, params.eventId));

        await processPlayoffEvent(params.eventId, db);
      }

      // Assign 0 points to participants not in the bracket (Q20)
      const { setParticipantResult } = await import("~/models/participant-result");
      for (const participant of allParticipants) {
        if (!participantsInMatches.has(participant.id)) {
          await setParticipantResult(
            participant.id,
            params.id,
            0 // 0 placement = 0 points
          );
        }
      }

      // Mark event as complete
      await db
        .update(schema.scoringEvents)
        .set({ isComplete: true, completedAt: new Date(), updatedAt: new Date() })
        .where(eq(schema.scoringEvents.id, params.eventId));

      // Recalculate standings for all affected fantasy seasons
      const { recalculateStandings } = await import("~/models/scoring-calculator");
      const { findSeasonSportsBySportsSeasonId } = await import("~/models/season-sport");
      const seasonSports = await findSeasonSportsBySportsSeasonId(params.id);

      for (const seasonSport of seasonSports) {
        await recalculateStandings(seasonSport.seasonId, db);
      }

      return {
        success: `Bracket finalized! All placements calculated and standings updated.`,
      };
    } catch (error) {
      console.error("Error finalizing bracket:", error);
      return {
        error:
          error instanceof Error ? error.message : "Failed to finalize bracket",
      };
    }
  }

  if (intent === "generate-groups") {
    const templateId = formData.get("templateId");

    if (typeof templateId !== "string" || !templateId) {
      return { error: "Template ID is required" };
    }

    const template = getBracketTemplate(templateId);
    if (!template || !template.groupStage) {
      return { error: "Invalid template or template has no group stage" };
    }

    const { groupStage } = template;
    const totalTeams = groupStage.groupCount * groupStage.teamsPerGroup;

    // Collect participant IDs from form
    const participantIds: string[] = [];
    for (let i = 0; i < totalTeams; i++) {
      const participantId = formData.get(`participant${i}`);
      if (typeof participantId !== "string" || !participantId) {
        return { error: `Participant ${i + 1} is required` };
      }
      participantIds.push(participantId);
    }

    // Check for duplicates
    const uniqueParticipants = new Set(participantIds);
    if (uniqueParticipants.size !== participantIds.length) {
      return { error: "Each participant can only be selected once" };
    }

    try {
      // Update the event with template info
      await updateScoringEvent(params.eventId, {
        bracketTemplateId: templateId,
        scoringStartsAtRound: template.scoringStartsAtRound,
      });

      // Create tournament groups
      const groups = await createGroupsForEvent(params.eventId, groupStage.groupLabels);

      // Distribute participants into groups (in selection order)
      for (let groupIndex = 0; groupIndex < groups.length; groupIndex++) {
        const startIdx = groupIndex * groupStage.teamsPerGroup;
        const groupParticipantIds = participantIds.slice(
          startIdx,
          startIdx + groupStage.teamsPerGroup
        );
        await addMembersToGroup(groups[groupIndex].id, groupParticipantIds);
      }

      // Generate the empty knockout bracket structure
      await generateBracketFromTemplate(params.eventId, templateId);

      return { success: "Groups and knockout bracket structure created successfully" };
    } catch (error) {
      console.error("Error generating groups:", error);
      return {
        error: error instanceof Error ? error.message : "Failed to generate groups",
      };
    }
  }

  if (intent === "toggle-elimination") {
    const memberId = formData.get("memberId");

    if (typeof memberId !== "string" || !memberId) {
      return { error: "Member ID is required" };
    }

    try {
      const updated = await toggleMemberEliminated(memberId);
      return {
        success: updated.eliminated
          ? "Team marked as eliminated"
          : "Team reinstated",
      };
    } catch (error) {
      console.error("Error toggling elimination:", error);
      return {
        error: error instanceof Error ? error.message : "Failed to toggle elimination",
      };
    }
  }

  if (intent === "populate-knockout") {
    try {
      const event = await getScoringEventById(params.eventId);
      if (!event) {
        return { error: "Event not found" };
      }

      // Parse match assignments from form
      const assignments: Array<{
        matchNumber: number;
        slot: "participant1Id" | "participant2Id";
        participantId: string;
      }> = [];

      for (const [key, value] of formData.entries()) {
        const matchPattern = /^match-(\d+)-(participant1Id|participant2Id)$/;
        const match = key.match(matchPattern);
        if (match && typeof value === "string" && value) {
          assignments.push({
            matchNumber: parseInt(match[1], 10),
            slot: match[2] as "participant1Id" | "participant2Id",
            participantId: value,
          });
        }
      }

      if (assignments.length !== 32) {
        return { error: `Expected 32 assignments but got ${assignments.length}` };
      }

      // Validate all assignments are unique participants
      const assignedParticipantIds = new Set(assignments.map((a) => a.participantId));
      if (assignedParticipantIds.size !== 32) {
        return { error: "All 32 knockout slots must have unique participants" };
      }

      // Validate all assigned participants are non-eliminated
      const advancingIds = new Set(await getAdvancingParticipantIds(params.eventId));
      for (const participantId of assignedParticipantIds) {
        if (!advancingIds.has(participantId)) {
          return { error: "All assigned participants must be non-eliminated group members" };
        }
      }

      // Assign participants to knockout bracket
      await assignParticipantsToKnockout(params.eventId, assignments);

      // Mark eliminated group participants with finalPosition = 0
      const eliminatedIds = await getEliminatedParticipantIds(params.eventId);
      const { setParticipantResult } = await import("~/models/participant-result");
      for (const participantId of eliminatedIds) {
        await setParticipantResult(participantId, event.sportsSeasonId, 0);
      }

      console.log(
        `[PopulateKnockout] Assigned 32 participants to knockout, marked ${eliminatedIds.length} as eliminated`
      );

      return { success: "Knockout bracket populated successfully" };
    } catch (error) {
      console.error("Error populating knockout:", error);
      return {
        error: error instanceof Error ? error.message : "Failed to populate knockout",
      };
    }
  }

  return { error: "Invalid action" };
}