import { BadRequestException, ConflictException, Injectable, NotFoundException } from "@nestjs/common";
import {
  auditRepo,
  inventoryRepo,
  productsRepo,
  type SerializedAsset,
  type StockMovement,
  type StockReservation,
} from "@eden/database";
import type { CreateAssetDto } from "./dto/create-asset.dto.js";
import type { ReserveAssetDto } from "./dto/reserve-asset.dto.js";
import type { InstallAssetDto } from "./dto/install-asset.dto.js";
import type { ReturnAssetDto } from "./dto/return-asset.dto.js";
import type { CreateReservationDto } from "./dto/create-reservation.dto.js";
import type { EdenAuthenticatedUser } from "../auth/jwt-auth.guard.js";

const {
  AssetNotFoundError,
  InvalidAssetTransitionError,
  NoOpenAssignmentError,
  ReservationNotFoundError,
  InvalidReservationTransitionError,
} = inventoryRepo;

@Injectable()
export class InventoryService {
  // ---------------------------------------------------------------------
  // serialized_assets
  // ---------------------------------------------------------------------

  listAssets(status?: string, warehouseId?: string, productId?: string): Promise<SerializedAsset[]> {
    return inventoryRepo.listSerializedAssets({
      status: status as SerializedAsset["status"] | undefined,
      warehouseId,
      productId,
    });
  }

  async getAsset(id: string): Promise<SerializedAsset> {
    const asset = await inventoryRepo.getSerializedAssetById(id);
    if (!asset) throw new NotFoundException("Ativo não encontrado");
    return asset;
  }

  async createAsset(dto: CreateAssetDto, user: EdenAuthenticatedUser): Promise<SerializedAsset> {
    if (!dto.serial && !dto.patrimonyTag) {
      throw new BadRequestException("Informe ao menos serial ou patrimonyTag");
    }

    const product = await productsRepo.getProductById(dto.productId);
    if (!product) throw new BadRequestException(`Produto ${dto.productId} não encontrado`);

    const warehouse = await inventoryRepo.getWarehouseById(dto.warehouseId);
    if (!warehouse) throw new BadRequestException(`Armazém ${dto.warehouseId} não encontrado`);

    let result: Awaited<ReturnType<typeof inventoryRepo.createAssetWithPurchaseMovement>>;
    try {
      result = await inventoryRepo.createAssetWithPurchaseMovement({
        productId: dto.productId,
        warehouseId: dto.warehouseId,
        serial: dto.serial ?? null,
        patrimonyTag: dto.patrimonyTag ?? null,
        macAddress: dto.macAddress ?? null,
        warrantyExpiresAt: dto.warrantyExpiresAt ?? null,
        notes: dto.notes ?? null,
        createdBy: user.id,
      });
    } catch (err) {
      // 23505 = unique_violation — the DB-enforced "serial/patrimony/MAC
      // never active twice" invariant (see migration).
      if (isUniqueViolation(err)) {
        throw new ConflictException(
          "Serial, patrimônio ou MAC já está em uso por outro ativo ativo",
        );
      }
      throw err;
    }

    await auditRepo.appendAuditEvent({
      actorType: "user",
      actorId: user.id,
      action: "inventory.asset_created",
      resourceType: "serialized_asset",
      resourceId: result.asset.id,
      metadata: { productId: dto.productId, warehouseId: dto.warehouseId, serial: dto.serial ?? null },
    });

    return result.asset;
  }

  async reserveAsset(id: string, dto: ReserveAssetDto, user: EdenAuthenticatedUser): Promise<SerializedAsset> {
    try {
      const result = await inventoryRepo.reserveAsset(id, {
        referenceType: dto.referenceType ?? null,
        referenceId: dto.referenceId ?? null,
        notes: dto.notes ?? null,
        createdBy: user.id,
      });

      await auditRepo.appendAuditEvent({
        actorType: "user",
        actorId: user.id,
        action: "inventory.asset_reserved",
        resourceType: "serialized_asset",
        resourceId: id,
        metadata: { reservationId: result.reservation.id },
      });

      return result.asset;
    } catch (err) {
      if (err instanceof AssetNotFoundError) throw new NotFoundException("Ativo não encontrado");
      if (err instanceof InvalidAssetTransitionError) {
        throw new ConflictException(
          `Ativo com status '${err.fromStatus}' não pode ser reservado (esperado: in_stock)`,
        );
      }
      throw err;
    }
  }

  async installAsset(id: string, dto: InstallAssetDto, user: EdenAuthenticatedUser): Promise<SerializedAsset> {
    try {
      const result = await inventoryRepo.installAsset(id, {
        contractId: dto.contractId,
        assignmentType: dto.assignmentType,
        notes: dto.notes ?? null,
        createdBy: user.id,
      });

      await auditRepo.appendAuditEvent({
        actorType: "user",
        actorId: user.id,
        action: "inventory.asset_installed",
        resourceType: "serialized_asset",
        resourceId: id,
        metadata: { contractId: dto.contractId, assignmentType: dto.assignmentType },
      });

      return result.asset;
    } catch (err) {
      if (err instanceof AssetNotFoundError) throw new NotFoundException("Ativo não encontrado");
      if (err instanceof InvalidAssetTransitionError) {
        throw new ConflictException(
          `Ativo com status '${err.fromStatus}' não pode ser instalado/comodato (esperado: in_stock ou reserved)`,
        );
      }
      throw err;
    }
  }

  async returnAsset(id: string, dto: ReturnAssetDto, user: EdenAuthenticatedUser): Promise<SerializedAsset> {
    const warehouse = await inventoryRepo.getWarehouseById(dto.warehouseId);
    if (!warehouse) throw new BadRequestException(`Armazém ${dto.warehouseId} não encontrado`);

    try {
      const result = await inventoryRepo.returnAsset(id, {
        warehouseId: dto.warehouseId,
        notes: dto.notes ?? null,
        createdBy: user.id,
      });

      await auditRepo.appendAuditEvent({
        actorType: "user",
        actorId: user.id,
        action: "inventory.asset_returned",
        resourceType: "serialized_asset",
        resourceId: id,
        metadata: { warehouseId: dto.warehouseId },
      });

      return result.asset;
    } catch (err) {
      if (err instanceof AssetNotFoundError) throw new NotFoundException("Ativo não encontrado");
      if (err instanceof InvalidAssetTransitionError) {
        throw new ConflictException(
          `Ativo com status '${err.fromStatus}' não pode ser devolvido (esperado: installed ou comodato)`,
        );
      }
      if (err instanceof NoOpenAssignmentError) {
        throw new ConflictException("Ativo não tem vínculo aberto para encerrar");
      }
      throw err;
    }
  }

  // ---------------------------------------------------------------------
  // stock_movements
  // ---------------------------------------------------------------------

  listMovements(
    warehouseId?: string,
    productId?: string,
    referenceType?: string,
    referenceId?: string,
  ): Promise<StockMovement[]> {
    return inventoryRepo.listStockMovements({ warehouseId, productId, referenceType, referenceId });
  }

  // ---------------------------------------------------------------------
  // stock_reservations
  // ---------------------------------------------------------------------

  listReservations(status?: string, warehouseId?: string, productId?: string): Promise<StockReservation[]> {
    return inventoryRepo.listStockReservations({
      status: status as StockReservation["status"] | undefined,
      warehouseId,
      productId,
    });
  }

  async createReservation(dto: CreateReservationDto, user: EdenAuthenticatedUser): Promise<StockReservation> {
    const product = await productsRepo.getProductById(dto.productId);
    if (!product) throw new BadRequestException(`Produto ${dto.productId} não encontrado`);

    const warehouse = await inventoryRepo.getWarehouseById(dto.warehouseId);
    if (!warehouse) throw new BadRequestException(`Armazém ${dto.warehouseId} não encontrado`);

    const result = await inventoryRepo.createGenericReservation({
      warehouseId: dto.warehouseId,
      productId: dto.productId,
      quantity: dto.quantity,
      referenceType: dto.referenceType ?? null,
      referenceId: dto.referenceId ?? null,
      notes: dto.notes ?? null,
      createdBy: user.id,
    });

    await auditRepo.appendAuditEvent({
      actorType: "user",
      actorId: user.id,
      action: "inventory.reservation_created",
      resourceType: "stock_reservation",
      resourceId: result.reservation.id,
      metadata: { productId: dto.productId, warehouseId: dto.warehouseId, quantity: dto.quantity },
    });

    return result.reservation;
  }

  async releaseReservation(id: string, user: EdenAuthenticatedUser): Promise<StockReservation> {
    try {
      const result = await inventoryRepo.releaseReservation(id, user.id);

      await auditRepo.appendAuditEvent({
        actorType: "user",
        actorId: user.id,
        action: "inventory.reservation_released",
        resourceType: "stock_reservation",
        resourceId: id,
        metadata: {},
      });

      return result.reservation;
    } catch (err) {
      if (err instanceof ReservationNotFoundError) throw new NotFoundException("Reserva não encontrada");
      if (err instanceof InvalidReservationTransitionError) {
        throw new ConflictException(
          `Reserva com status '${err.fromStatus}' não pode ser liberada (esperado: active)`,
        );
      }
      throw err;
    }
  }
}

function isUniqueViolation(err: unknown): boolean {
  return typeof err === "object" && err !== null && (err as { code?: string }).code === "23505";
}