import { Injectable } from '@nestjs/common';
import { PrismaService } from '../prisma/prisma.service';

@Injectable()
export class StatisticsService {
  constructor(private readonly prisma: PrismaService) {}

  async colonies() {
    const [byStatus, strengthOverTime, losses] = await Promise.all([
      this.prisma.colony.groupBy({ by: ['status'], _count: { _all: true } }),
      this.prisma.inspection.findMany({
        where: { colonyStrength: { not: null } },
        select: { colonyId: true, date: true, colonyStrength: true },
        orderBy: { date: 'asc' },
      }),
      this.prisma.colony.findMany({
        where: { status: { in: ['DECEASED', 'DISSOLVED'] } },
        select: { deactivatedAt: true, updatedAt: true },
      }),
    ]);

    const lossesByYear: Record<string, number> = {};
    for (const loss of losses) {
      const year = (loss.deactivatedAt ?? loss.updatedAt)
        .getFullYear()
        .toString();
      lossesByYear[year] = (lossesByYear[year] ?? 0) + 1;
    }

    return {
      byStatus: byStatus.map((row) => ({
        status: row.status,
        count: row._count._all,
      })),
      strengthOverTime,
      lossesByYear,
    };
  }

  async queens() {
    const [queens, evaluations] = await Promise.all([
      this.prisma.queen.findMany({
        select: {
          id: true,
          code: true,
          status: true,
          createdAt: true,
          deactivatedAt: true,
        },
      }),
      this.prisma.queenEvaluation.findMany({
        select: {
          queenId: true,
          colonyStrength: true,
          gentleness: true,
          combBuild: true,
          swarmingTendency: true,
          broodPattern: true,
          honeyYield: true,
        },
      }),
    ]);

    const retiredQueens = queens.filter(
      (queen) => queen.deactivatedAt !== null,
    );
    const averageLifespanDays =
      retiredQueens.length > 0
        ? retiredQueens.reduce((sum, queen) => {
            const days =
              (queen.deactivatedAt!.getTime() - queen.createdAt.getTime()) /
              (1000 * 60 * 60 * 24);
            return sum + days;
          }, 0) / retiredQueens.length
        : null;

    const byQueen = new Map<string, typeof evaluations>();
    for (const evaluation of evaluations) {
      const bucket = byQueen.get(evaluation.queenId) ?? [];
      bucket.push(evaluation);
      byQueen.set(evaluation.queenId, bucket);
    }

    function average(values: number[]): number {
      return values.reduce((sum, value) => sum + value, 0) / values.length;
    }

    const evaluationAverages = queens
      .filter((queen) => byQueen.has(queen.id))
      .map((queen) => {
        const rows = byQueen.get(queen.id)!;
        return {
          queenId: queen.id,
          code: queen.code,
          evaluationCount: rows.length,
          colonyStrength: average(rows.map((row) => row.colonyStrength)),
          gentleness: average(rows.map((row) => row.gentleness)),
          combBuild: average(rows.map((row) => row.combBuild)),
          swarmingTendency: average(rows.map((row) => row.swarmingTendency)),
          broodPattern: average(rows.map((row) => row.broodPattern)),
          honeyYield: average(rows.map((row) => row.honeyYield)),
        };
      })
      .sort((a, b) => b.honeyYield - a.honeyYield);

    return {
      totalActive: queens.filter((queen) => queen.status === 'ACTIVE').length,
      averageLifespanDays,
      evaluationAverages,
    };
  }

  async apiaries() {
    const apiaries = await this.prisma.apiary.findMany({
      select: {
        id: true,
        name: true,
        colonies: { select: { id: true, status: true } },
        harvests: { select: { netWeight: true } },
      },
    });

    return apiaries.map((apiary) => {
      const totalHoneyKg = apiary.harvests.reduce(
        (sum, harvest) => sum + (harvest.netWeight ?? 0),
        0,
      );
      const activeColonies = apiary.colonies.filter(
        (c) => c.status === 'ACTIVE',
      ).length;
      const lostColonies = apiary.colonies.filter((c) =>
        ['DECEASED', 'DISSOLVED'].includes(c.status),
      ).length;
      return {
        apiaryId: apiary.id,
        name: apiary.name,
        activeColonies,
        lostColonies,
        totalHoneyKg,
        averageHoneyKgPerColony:
          apiary.colonies.length > 0
            ? totalHoneyKg / apiary.colonies.length
            : 0,
      };
    });
  }

  async varroa() {
    const measurements = await this.prisma.varroaMeasurement.findMany({
      where: { miteCount: { not: null } },
      select: { colonyId: true, date: true, miteCount: true, method: true },
      orderBy: { date: 'asc' },
    });
    const treatmentsByColony = await this.prisma.treatment.groupBy({
      by: ['colonyId'],
      _count: { _all: true },
    });

    return {
      measurements,
      treatmentCountByColony: treatmentsByColony.map((row) => ({
        colonyId: row.colonyId,
        treatmentCount: row._count._all,
      })),
    };
  }

  async honey() {
    const [harvests, honeyBatches] = await Promise.all([
      this.prisma.harvest.findMany({
        select: { apiaryId: true, date: true, netWeight: true },
      }),
      this.prisma.honeyBatch.findMany({
        select: { amount: true, createdAt: true },
      }),
    ]);

    const totalHarvestKg = harvests.reduce(
      (sum, h) => sum + (h.netWeight ?? 0),
      0,
    );
    const totalHoneyBatchKg = honeyBatches.reduce(
      (sum, b) => sum + (b.amount ?? 0),
      0,
    );

    const yieldPerYear: Record<string, number> = {};
    const yieldPerApiary: Record<string, number> = {};
    for (const harvest of harvests) {
      const year = harvest.date.getFullYear().toString();
      yieldPerYear[year] = (yieldPerYear[year] ?? 0) + (harvest.netWeight ?? 0);
      yieldPerApiary[harvest.apiaryId] =
        (yieldPerApiary[harvest.apiaryId] ?? 0) + (harvest.netWeight ?? 0);
    }

    return {
      totalHarvestKg,
      totalHoneyBatchKg,
      yieldPerYear,
      yieldPerApiary,
    };
  }

  async feeding() {
    const feedings = await this.prisma.feeding.findMany({
      select: { colonyId: true, date: true, amount: true, unit: true },
    });

    const byColony: Record<string, number> = {};
    const bySeason: Record<string, number> = {};
    for (const feeding of feedings) {
      byColony[feeding.colonyId] =
        (byColony[feeding.colonyId] ?? 0) + feeding.amount;
      const year = feeding.date.getFullYear().toString();
      bySeason[year] = (bySeason[year] ?? 0) + feeding.amount;
    }

    return { byColony, bySeason };
  }
}