import { database } from "~/database/context";
import * as schema from "~/database/schema";
import { eq, and, desc } from "drizzle-orm";

export interface TeamStanding {
  teamId: string;
  teamName: string;
  totalPoints: number;
  currentRank: number;
  previousRank: number | null;
  rankChange: number; // Positive = moved up, negative = moved down
  placementCounts: {
    first: number;
    second: number;
    third: number;
    fourth: number;
    fifth: number;
    sixth: number;
    seventh: number;
    eighth: number;
  };
  participantsRemaining: number;
  calculatedAt: Date;
}

export interface TeamStandingSnapshot {
  date: Date;
  rank: number;
  totalPoints: number;
}

/**
 * Get current standings for a season
 */
export async function getSeasonStandings(
  seasonId: string,
  providedDb?: ReturnType<typeof database>
): Promise<TeamStanding[]> {
  const db = providedDb || database();

  const standings = await db.query.teamStandings.findMany({
    where: eq(schema.teamStandings.seasonId, seasonId),
    orderBy: [
      desc(schema.teamStandings.currentRank), // Lower rank number = better
      desc(schema.teamStandings.totalPoints),
    ],
    with: {
      team: true,
    },
  });

  return standings.map((standing) => ({
    teamId: standing.teamId,
    teamName: standing.team.name,
    totalPoints: parseFloat(standing.totalPoints),
    currentRank: standing.currentRank,
    previousRank: standing.previousRank,
    rankChange: standing.previousRank
      ? standing.previousRank - standing.currentRank
      : 0,
    placementCounts: {
      first: standing.firstPlaceCount,
      second: standing.secondPlaceCount,
      third: standing.thirdPlaceCount,
      fourth: standing.fourthPlaceCount,
      fifth: standing.fifthPlaceCount,
      sixth: standing.sixthPlaceCount,
      seventh: standing.seventhPlaceCount,
      eighth: standing.eighthPlaceCount,
    },
    participantsRemaining: standing.participantsRemaining,
    calculatedAt: standing.calculatedAt,
  }));
}

/**
 * Get standings for a specific team
 */
export async function getTeamStanding(
  teamId: string,
  seasonId: string,
  providedDb?: ReturnType<typeof database>
): Promise<TeamStanding | null> {
  const db = providedDb || database();

  const standing = await db.query.teamStandings.findFirst({
    where: and(
      eq(schema.teamStandings.teamId, teamId),
      eq(schema.teamStandings.seasonId, seasonId)
    ),
    with: {
      team: true,
    },
  });

  if (!standing) return null;

  return {
    teamId: standing.teamId,
    teamName: standing.team.name,
    totalPoints: parseFloat(standing.totalPoints),
    currentRank: standing.currentRank,
    previousRank: standing.previousRank,
    rankChange: standing.previousRank
      ? standing.previousRank - standing.currentRank
      : 0,
    placementCounts: {
      first: standing.firstPlaceCount,
      second: standing.secondPlaceCount,
      third: standing.thirdPlaceCount,
      fourth: standing.fourthPlaceCount,
      fifth: standing.fifthPlaceCount,
      sixth: standing.sixthPlaceCount,
      seventh: standing.seventhPlaceCount,
      eighth: standing.eighthPlaceCount,
    },
    participantsRemaining: standing.participantsRemaining,
    calculatedAt: standing.calculatedAt,
  };
}

/**
 * Get detailed team breakdown with all picks and their points
 */
export async function getTeamScoreBreakdown(
  teamId: string,
  seasonId: string,
  providedDb?: ReturnType<typeof database>
) {
  const db = providedDb || database();

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

  if (!season) return null;

  // Get all draft picks for this team with participant details
  const picks = await db.query.draftPicks.findMany({
    where: and(
      eq(schema.draftPicks.teamId, teamId),
      eq(schema.draftPicks.seasonId, seasonId)
    ),
    orderBy: schema.draftPicks.pickNumber,
    with: {
      participant: {
        with: {
          sportsSeason: {
            with: {
              sport: true,
            },
          },
          results: true,
        },
      },
    },
  });

  // Calculate points for each pick
  const pickBreakdown = picks.map((pick) => {
    const result = pick.participant.results[0];
    let points = 0;

    if (result && result.finalPosition) {
      // Calculate points based on placement
      const pointsMap: Record<number, number> = {
        1: season.pointsFor1st,
        2: season.pointsFor2nd,
        3: season.pointsFor3rd,
        4: season.pointsFor4th,
        5: season.pointsFor5th,
        6: season.pointsFor6th,
        7: season.pointsFor7th,
        8: season.pointsFor8th,
      };
      points = pointsMap[result.finalPosition] || 0;
    }

    return {
      pickNumber: pick.pickNumber,
      round: pick.round,
      participant: {
        id: pick.participant.id,
        name: pick.participant.name,
        sport: pick.participant.sportsSeason.sport.name,
      },
      finalPosition: result?.finalPosition || null,
      points,
      isComplete: !!result?.finalPosition,
    };
  });

  // Group by sport for easier display
  const bySport: Record<string, typeof pickBreakdown> = {};
  for (const pick of pickBreakdown) {
    const sport = pick.participant.sport;
    if (!bySport[sport]) {
      bySport[sport] = [];
    }
    bySport[sport].push(pick);
  }

  return {
    team: await db.query.teams.findFirst({
      where: eq(schema.teams.id, teamId),
    }),
    picks: pickBreakdown,
    bySport,
    totalPoints: pickBreakdown.reduce((sum, p) => sum + p.points, 0),
    completedCount: pickBreakdown.filter((p) => p.isComplete).length,
    totalCount: pickBreakdown.length,
  };
}

/**
 * Get historical standings snapshots for a team
 * Used to display point progression over time
 */
export async function getTeamStandingsHistory(
  teamId: string,
  seasonId: string,
  providedDb?: ReturnType<typeof database>
): Promise<TeamStandingSnapshot[]> {
  const db = providedDb || database();

  const snapshots = await db.query.teamStandingsSnapshots.findMany({
    where: and(
      eq(schema.teamStandingsSnapshots.teamId, teamId),
      eq(schema.teamStandingsSnapshots.seasonId, seasonId)
    ),
    orderBy: schema.teamStandingsSnapshots.snapshotDate,
  });

  return snapshots.map((snapshot) => ({
    date: new Date(snapshot.snapshotDate),
    rank: snapshot.rank,
    totalPoints: parseFloat(snapshot.totalPoints),
  }));
}

/**
 * Get standings comparison between current and 7 days ago
 * Used for "7-day change" display
 */
export async function getSevenDayStandingsChange(
  seasonId: string,
  providedDb?: ReturnType<typeof database>
) {
  const db = providedDb || database();

  const sevenDaysAgo = new Date();
  sevenDaysAgo.setDate(sevenDaysAgo.getDate() - 7);

  // Get current standings
  const current = await getSeasonStandings(seasonId, db);

  // Get snapshots from 7 days ago
  const snapshots = await db.query.teamStandingsSnapshots.findMany({
    where: and(
      eq(schema.teamStandingsSnapshots.seasonId, seasonId),
      eq(schema.teamStandingsSnapshots.snapshotDate, sevenDaysAgo.toISOString().split("T")[0])
    ),
  });

  // Create a map of team -> old rank
  const oldRanks = new Map<string, number>();
  for (const snapshot of snapshots) {
    oldRanks.set(snapshot.teamId, snapshot.rank);
  }

  // Add 7-day changes to current standings
  return current.map((standing) => ({
    ...standing,
    sevenDayRankChange: oldRanks.has(standing.teamId)
      ? oldRanks.get(standing.teamId)! - standing.currentRank
      : 0,
    sevenDayOldRank: oldRanks.get(standing.teamId) || null,
  }));
}

/**
 * Create a daily standings snapshot
 * Should be called by a scheduled job once per day
 */
export async function createDailySnapshot(
  seasonId: string,
  providedDb?: ReturnType<typeof database>
): Promise<void> {
  const db = providedDb || database();

  const today = new Date().toISOString().split("T")[0];

  const standings = await db.query.teamStandings.findMany({
    where: eq(schema.teamStandings.seasonId, seasonId),
  });

  for (const standing of standings) {
    // Check if snapshot already exists for today
    const existing = await db.query.teamStandingsSnapshots.findFirst({
      where: and(
        eq(schema.teamStandingsSnapshots.teamId, standing.teamId),
        eq(schema.teamStandingsSnapshots.seasonId, seasonId),
        eq(schema.teamStandingsSnapshots.snapshotDate, today)
      ),
    });

    if (!existing) {
      await db.insert(schema.teamStandingsSnapshots).values({
        teamId: standing.teamId,
        seasonId,
        snapshotDate: today,
        totalPoints: standing.totalPoints,
        rank: standing.currentRank,
        firstPlaceCount: standing.firstPlaceCount,
        secondPlaceCount: standing.secondPlaceCount,
        thirdPlaceCount: standing.thirdPlaceCount,
        fourthPlaceCount: standing.fourthPlaceCount,
        fifthPlaceCount: standing.fifthPlaceCount,
        sixthPlaceCount: standing.sixthPlaceCount,
        seventhPlaceCount: standing.seventhPlaceCount,
        eighthPlaceCount: standing.eighthPlaceCount,
        participantsRemaining: standing.participantsRemaining,
      });
    }
  }

  console.log(`[Standings] Created daily snapshot for season ${seasonId}`);
}