import { getAuth } from "@clerk/react-router/server";
import { database } from "~/database/context";
import * as schema from "~/database/schema";
import { eq, and } from "drizzle-orm";
import { isCommissioner } from "~/models/commissioner";
import { calculateDraftEligibility } from "~/lib/draft-eligibility";
import { getDraftPicksWithSports, getTeamDraftPicksWithSports } from "~/models/draft-pick";
import { getParticipantsForSeasonWithSports } from "~/models/participant";
import { getSeasonSportsSimple } from "~/models/season-sport";
import { getSocketIO } from "../../../server/socket";
import { logger } from "~/lib/logger";

import type { ActionFunctionArgs } from "react-router";
export async function action(args: ActionFunctionArgs) {
  const { request } = args;
  const { userId } = await getAuth(args);

  if (!userId) {
    return Response.json({ error: "Unauthorized" }, { status: 401 });
  }

  const formData = await request.formData();
  const seasonId = formData.get("seasonId") as string;
  const participantId = formData.get("participantId") as string;
  const pickNumber = parseInt(formData.get("pickNumber") as string);

  if (!seasonId || !participantId || isNaN(pickNumber) || pickNumber < 1) {
    return Response.json({ error: "Missing required fields" }, { status: 400 });
  }

  const db = database();

  const season = await db.query.seasons.findFirst({
    where: eq(schema.seasons.id, seasonId),
  });

  if (!season) {
    return Response.json({ error: "Season not found" }, { status: 404 });
  }

  if (!(await isCommissioner(season.leagueId, userId))) {
    return Response.json({ error: "Only commissioners can replace picks" }, { status: 403 });
  }

  if (season.status === "pre_draft") {
    return Response.json({ error: "Draft has not started" }, { status: 400 });
  }

  // Get the existing pick at this slot
  const existingPick = await db.query.draftPicks.findFirst({
    where: and(
      eq(schema.draftPicks.seasonId, seasonId),
      eq(schema.draftPicks.pickNumber, pickNumber)
    ),
  });

  if (!existingPick) {
    return Response.json({ error: "No pick found at this slot" }, { status: 404 });
  }

  // Use the team from the DB record — don't trust the client-supplied teamId
  const teamId = existingPick.teamId;
  const oldParticipantId = existingPick.participantId;

  // Check new participant isn't already drafted elsewhere (skip if same participant)
  if (participantId !== oldParticipantId) {
    const alreadyDrafted = await db.query.draftPicks.findFirst({
      where: and(
        eq(schema.draftPicks.seasonId, seasonId),
        eq(schema.draftPicks.participantId, participantId)
      ),
    });

    if (alreadyDrafted) {
      return Response.json({ error: "Participant already drafted" }, { status: 400 });
    }
  }

  const participant = await db.query.participants.findFirst({
    where: eq(schema.participants.id, participantId),
    with: {
      sportsSeason: { with: { sport: true } },
    },
  });

  if (!participant) {
    return Response.json({ error: "Participant not found" }, { status: 404 });
  }

  // Eligibility check — exclude the pick being replaced so its slot is treated as free
  const draftSlots = await db.query.draftSlots.findMany({
    where: eq(schema.draftSlots.seasonId, seasonId),
    orderBy: schema.draftSlots.draftOrder,
    with: { team: true },
  });

  const allPicksWithSports = await getDraftPicksWithSports(seasonId);
  const teamPicksWithSports = await getTeamDraftPicksWithSports(teamId, seasonId);
  const allParticipants = await getParticipantsForSeasonWithSports(seasonId);
  const seasonSports = await getSeasonSportsSimple(seasonId);

  // Exclude old participant so that slot is "open" for eligibility purposes
  const allPicksExcluding = allPicksWithSports.filter(
    (p) => p.participant.id !== oldParticipantId
  );
  const teamPicksExcluding = teamPicksWithSports.filter(
    (p) => p.participant.id !== oldParticipantId
  );

  const allTeams = draftSlots.map((slot) => ({ id: slot.teamId }));

  const eligibility = calculateDraftEligibility(
    teamId,
    teamPicksExcluding,
    allPicksExcluding,
    allParticipants,
    seasonSports,
    season.draftRounds,
    allTeams
  );

  const sportId = participant.sportsSeason.sport.id;
  if (!eligibility.eligibleSportIds.has(sportId)) {
    const reason = eligibility.ineligibleReasons[sportId] || "Cannot draft from this sport";
    return Response.json({ error: reason }, { status: 400 });
  }

  // Update the pick in-place
  const [updatedPick] = await db
    .update(schema.draftPicks)
    .set({
      participantId,
      pickedByUserId: userId,
      pickedByType: "commissioner",
    })
    .where(
      and(
        eq(schema.draftPicks.seasonId, seasonId),
        eq(schema.draftPicks.pickNumber, pickNumber)
      )
    )
    .returning();

  // Remove new participant from all team queues
  await db
    .delete(schema.draftQueue)
    .where(
      and(
        eq(schema.draftQueue.seasonId, seasonId),
        eq(schema.draftQueue.participantId, participantId)
      )
    );

  // Emit socket events
  try {
    const io = getSocketIO();
    const team = draftSlots.find((slot) => slot.team.id === teamId)?.team;

    io.to(`draft-${seasonId}`).emit("pick-replaced", {
      seasonId,
      pickNumber,
      oldParticipantId,
      pick: {
        id: updatedPick.id,
        pickNumber: updatedPick.pickNumber,
        round: updatedPick.round,
        pickInRound: updatedPick.pickInRound,
        timeUsed: updatedPick.timeUsed,
        team,
        participant: {
          id: participant.id,
          name: participant.name,
          sport: participant.sportsSeason.sport,
        },
        sport: participant.sportsSeason.sport,
      },
    });

    io.to(`draft-${seasonId}`).emit("participant-removed-from-queues", {
      participantId,
    });
  } catch (error) {
    logger.error("Socket.IO error:", error);
  }

  return Response.json({ success: true });
}