package com.baiyue.warehouse.service;

import com.baiyue.common.core.api.PageResult;
import com.baiyue.common.core.api.ResultCode;
import com.baiyue.common.core.exception.BizException;
import com.baiyue.warehouse.dto.LocationRequests;
import com.baiyue.warehouse.dto.PalletRequests;
import com.baiyue.warehouse.dto.WarehousePalletResolveResponse;
import com.baiyue.warehouse.dto.WarehouseLocationResolveResponse;
import com.baiyue.warehouse.dto.SharedWarehouseReference;
import com.baiyue.warehouse.entity.WarehouseLocationEntity;
import com.baiyue.warehouse.entity.WarehousePalletEntity;
import com.baiyue.warehouse.entity.WarehousePalletBindingEntity;
import com.baiyue.warehouse.repository.WarehouseResourceRepository;
import com.baomidou.mybatisplus.core.toolkit.IdWorker;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import jakarta.annotation.Resource;

import java.util.Set;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import org.springframework.util.StringUtils;

@Service
public class WarehouseResourceService {
    public static final long PUBLIC_RESOURCE_SCOPE = 0L;
    private static final Set<String> LOCATION_STATUSES = Set.of("ACTIVE", "IDLE", "OCCUPIED", "INACTIVE");
    private static final Set<String> PALLET_STATUSES = Set.of("IDLE", "OCCUPIED", "SCRAPPED");

    @Resource private WarehouseResourceRepository repository;
    @Resource private DomesticWarehouseDirectory warehouseDirectory;

    @Transactional
    public Long createLocation(long customerId, long warehouseId, LocationRequests.SaveRequest request) {
        requireWarehouse(customerId, warehouseId);
        validateLocation(request, customerId, warehouseId, null);
        WarehouseLocationEntity entity = locationEntity(customerId, warehouseId, request);
        repository.insertLocation(entity);
        return entity.getId();
    }

    @Transactional
    public void updateLocation(long customerId, long warehouseId, long id, LocationRequests.SaveRequest request) {
        WarehouseLocationEntity existing = requireLocation(customerId, warehouseId, id);
        if ("VIRTUAL".equals(existing.getLocationType())
            && (!"VIRTUAL".equals(request.locationType()) || !"ACTIVE".equals(request.status())
                || !existing.getLocationCode().equals(request.locationCode()))) {
            throw new BizException(ResultCode.CONFLICT, "Default virtual location must remain VIRTUAL and ACTIVE");
        }
        validateLocation(request, customerId, warehouseId, id);
        WarehouseLocationEntity entity = locationEntity(customerId, warehouseId, request);
        entity.setId(existing.getId());
        repository.updateLocation(entity);
    }

    public WarehouseLocationEntity location(long customerId, long warehouseId, long id) {
        requireWarehouse(customerId, warehouseId);
        return requireLocation(customerId, warehouseId, id);
    }

    public PageResult<WarehouseLocationEntity> locations(long customerId, long warehouseId,
                                                          LocationRequests.QueryRequest query) {
        requireWarehouse(customerId, warehouseId);
        return repository.pageLocations(customerId, warehouseId, query);
    }

    @Transactional
    public void deleteLocation(long customerId, long warehouseId, long id) {
        WarehouseLocationEntity location = requireLocation(customerId, warehouseId, id);
        if ("VIRTUAL".equals(location.getLocationType())) {
            throw new BizException(ResultCode.CONFLICT, "Default virtual location cannot be deleted");
        }
        if (repository.locationHasPallets(customerId, warehouseId, id)) {
            throw new BizException(ResultCode.CONFLICT, "库位仍绑定托盘，不能删除");
        }
        repository.deleteLocation(id);
    }

    @Transactional
    public Long createPallet(long customerId, long warehouseId, PalletRequests.SaveRequest request) {
        SharedWarehouseReference warehouse = requireWarehouseReference(warehouseId);
        validatePalletStatus(request.status());
        Long palletId = IdWorker.getId();
        String palletCode = StringUtils.hasText(request.palletCode()) ? request.palletCode().trim()
            : generatedPalletCode(warehouse.warehouseCode(), palletId);
        Long locationId = request.locationId();
        if (locationId == null) {
            locationId = ensureDefaultVirtualLocation(customerId, warehouseId).getId();
        }
        validatePallet(request, palletCode, locationId, customerId, warehouseId, null);
        WarehousePalletEntity entity = palletEntity(customerId, warehouseId, request, palletCode, locationId);
        entity.setId(palletId);
        repository.insertPallet(entity);
        return entity.getId();
    }

    @Transactional
    public WarehousePalletEntity ensureDropshipPallet(long customerId, long warehouseId, String businessId) {
        WarehousePalletBindingEntity existing = repository.findPalletBinding(customerId, warehouseId, "DROPSHIP", businessId);
        if (existing != null) return requirePallet(customerId, warehouseId, existing.getPalletId());
        Long palletId = createPallet(customerId, warehouseId,
            new PalletRequests.SaveRequest(null, "DROPSHIP", null, java.math.BigDecimal.ZERO, "IDLE", null,
                "Default dropship pallet for " + businessId));
        WarehousePalletBindingEntity binding = new WarehousePalletBindingEntity();
        binding.setId(IdWorker.getId()); binding.setCustomerId(customerId); binding.setWarehouseId(warehouseId);
        binding.setBusinessType("DROPSHIP"); binding.setBusinessId(businessId); binding.setPalletId(palletId);
        binding.setCreatedAt(java.time.LocalDateTime.now());
        try {
            repository.insertPalletBinding(binding);
            return requirePallet(customerId, warehouseId, palletId);
        } catch (org.springframework.dao.DuplicateKeyException duplicate) {
            WarehousePalletBindingEntity winner = repository.findPalletBinding(customerId, warehouseId, "DROPSHIP", businessId);
            if (winner == null) throw duplicate;
            return requirePallet(customerId, warehouseId, winner.getPalletId());
        }
    }

    /**
     * Returns the warehouse-scoped virtual location used only as a pallet/inventory reference.
     * It is deliberately never made IDLE/OCCUPIED by resource locking.
     */
    @Transactional
    public WarehouseLocationEntity ensureDefaultVirtualLocation(long customerId, long warehouseId) {
        SharedWarehouseReference warehouse = requireWarehouseReference(warehouseId);
        String locationCode = defaultLocationCode(warehouse.warehouseCode());
        WarehouseLocationEntity existing = repository.findLocationByCode(customerId, warehouseId, locationCode);
        if (existing != null) {
            if (!"VIRTUAL".equals(existing.getLocationType()) || !"ACTIVE".equals(existing.getStatus())) {
                throw new BizException(ResultCode.CONFLICT,
                    "Default virtual location code is occupied by a non-active virtual location");
            }
            return existing;
        }

        WarehouseLocationEntity location = new WarehouseLocationEntity();
        location.setId(IdWorker.getId());
        location.setCustomerId(customerId);
        location.setWarehouseId(warehouseId);
        location.setZoneCode("DEFAULT");
        location.setLocationCode(locationCode);
        location.setLocationType("VIRTUAL");
        location.setMaxLoadKg(new java.math.BigDecimal("999999999.000"));
        location.setStatus("ACTIVE");
        location.setRemark("System default virtual location");
        repository.insertDefaultVirtualLocationIgnore(location);

        WarehouseLocationEntity resolved = repository.findLocationByCode(customerId, warehouseId, locationCode);
        if (resolved == null) {
            throw new BizException(ResultCode.CONFLICT, "Default virtual location could not be created");
        }
        return resolved;
    }

    @Transactional
    public void updatePallet(long customerId, long warehouseId, long id, PalletRequests.SaveRequest request) {
        WarehousePalletEntity existing = requirePallet(customerId, warehouseId, id);
        if (request.version() == null || !request.version().equals(existing.getVersion())) {
            throw new BizException(ResultCode.CONFLICT, "托盘版本已变化，请刷新后重试");
        }
        if ("SCRAPPED".equals(existing.getStatus()) && !"SCRAPPED".equals(request.status())) {
            throw new BizException(ResultCode.CONFLICT, "SCRAPPED pallet cannot be reused");
        }
        String palletCode = StringUtils.hasText(request.palletCode()) ? request.palletCode().trim()
            : existing.getPalletCode();
        Long locationId = request.locationId() == null ? existing.getLocationId() : request.locationId();
        validatePallet(request, palletCode, locationId, customerId, warehouseId, id);
        WarehousePalletEntity entity = palletEntity(customerId, warehouseId, request, palletCode, locationId);
        entity.setId(existing.getId());
        entity.setVersion(request.version());
        if (repository.updatePallet(entity) != 1) {
            throw new BizException(ResultCode.CONFLICT, "托盘版本已变化，请刷新后重试");
        }
    }

    public WarehousePalletEntity pallet(long customerId, long warehouseId, long id) {
        requireWarehouse(customerId, warehouseId);
        return requirePallet(customerId, warehouseId, id);
    }

    public WarehousePalletResolveResponse resolvePublicPallet(String palletCode) {
        if (!StringUtils.hasText(palletCode)) {
            throw new BizException(ResultCode.BAD_REQUEST, "托盘码不能为空");
        }
        var matches = repository.findPublicPalletsByCode(palletCode.trim());
        if (matches.isEmpty()) throw new BizException(ResultCode.NOT_FOUND, "托盘码不存在");
        if (matches.size() != 1) throw new BizException(ResultCode.CONFLICT, "托盘码在多个仓库重复，无法解析");
        WarehousePalletEntity pallet = matches.get(0);
        if (pallet.getLocationId() == null) throw new BizException(ResultCode.CONFLICT, "托盘未绑定库位");
        if ("SCRAPPED".equals(pallet.getStatus())) throw new BizException(ResultCode.CONFLICT, "托盘已报废");
        return palletReference(pallet);
    }

    public WarehousePalletResolveResponse resolvePublicPallet(long palletId) {
        WarehousePalletEntity pallet = repository.findPublicPallet(palletId);
        if (pallet == null) throw new BizException(ResultCode.NOT_FOUND, "托盘不存在");
        if (pallet.getLocationId() == null) throw new BizException(ResultCode.CONFLICT, "托盘未绑定库位");
        return palletReference(pallet);
    }

    public WarehouseLocationResolveResponse resolvePublicLocation(long warehouseId, String locationCode) {
        if (!StringUtils.hasText(locationCode)) throw new BizException(ResultCode.BAD_REQUEST, "库位码不能为空");
        WarehouseLocationEntity location = repository.findLocationByCode(PUBLIC_RESOURCE_SCOPE, warehouseId,
            locationCode.trim());
        if (location == null) throw new BizException(ResultCode.NOT_FOUND, "库位码不存在或不属于当前仓库");
        return locationReference(location);
    }

    public WarehouseLocationResolveResponse resolvePublicLocation(long warehouseId, long locationId) {
        WarehouseLocationEntity location = repository.findLocation(PUBLIC_RESOURCE_SCOPE, warehouseId, locationId);
        if (location == null) throw new BizException(ResultCode.NOT_FOUND, "库位不存在或不属于当前仓库");
        return locationReference(location);
    }

    private static WarehouseLocationResolveResponse locationReference(WarehouseLocationEntity location) {
        return new WarehouseLocationResolveResponse(location.getId(), location.getLocationCode(),
            location.getLocationType(), location.getMaxLoadKg(), location.getStatus());
    }

    private WarehousePalletResolveResponse palletReference(WarehousePalletEntity pallet) {
        WarehouseLocationEntity location = repository.findLocation(PUBLIC_RESOURCE_SCOPE,
            pallet.getWarehouseId(), pallet.getLocationId());
        String blockReason = reservationBlockReason(pallet, location);
        return new WarehousePalletResolveResponse(pallet.getId(), pallet.getPalletCode(), pallet.getWarehouseId(),
            pallet.getLocationId(), pallet.getStatus(), pallet.getFbaWarehouseCode(), pallet.getUnitPrice(),
            pallet.getVersion() == null ? 0 : pallet.getVersion(),
            location == null ? null : location.getLocationType(),
            location == null ? null : location.getStatus(), blockReason == null, blockReason);
    }

    private static String reservationBlockReason(WarehousePalletEntity pallet, WarehouseLocationEntity location) {
        if (!"IDLE".equals(pallet.getStatus())) return "PALLET_NOT_IDLE";
        if (location == null) return "LOCATION_NOT_FOUND";
        if ("VIRTUAL".equals(location.getLocationType())) {
            return "ACTIVE".equals(location.getStatus()) ? null : "VIRTUAL_LOCATION_NOT_ACTIVE";
        }
        return "IDLE".equals(location.getStatus()) ? null : "LOCATION_NOT_IDLE";
    }

    public PageResult<WarehousePalletEntity> pallets(long customerId, long warehouseId,
                                                      PalletRequests.QueryRequest query) {
        requireWarehouse(customerId, warehouseId);
        return repository.pagePallets(customerId, warehouseId, query);
    }

    public PalletRequests.Summary palletSummary(long customerId, long warehouseId, PalletRequests.QueryRequest query) {
        requireWarehouse(customerId, warehouseId);
        long total = repository.countPallets(customerId, warehouseId, query, null);
        return new PalletRequests.Summary(total,
            repository.countPallets(customerId, warehouseId, query, "IDLE"),
            repository.countPallets(customerId, warehouseId, query, "OCCUPIED"),
            repository.countPallets(customerId, warehouseId, query, "SCRAPPED"));
    }

    public PalletRequests.Summary publicPalletSummary(long customerId, PalletRequests.QueryRequest query) {
        long total = repository.countPallets(customerId, (Long) null, query, null);
        return new PalletRequests.Summary(total,
            repository.countPallets(customerId, (Long) null, query, "IDLE"),
            repository.countPallets(customerId, (Long) null, query, "OCCUPIED"),
            repository.countPallets(customerId, (Long) null, query, "SCRAPPED"));
    }

    public PageResult<WarehousePalletEntity> publicPallets(long customerId,
                                                            PalletRequests.QueryRequest query) {
        return repository.pagePublicPallets(customerId, query);
    }

    @Transactional
    public void deletePallet(long customerId, long warehouseId, long id) {
        WarehousePalletEntity pallet = requirePallet(customerId, warehouseId, id);
        if ("OCCUPIED".equals(pallet.getStatus())) {
            throw new BizException(ResultCode.CONFLICT, "占用中的托盘不能删除");
        }
        if ("SCRAPPED".equals(pallet.getStatus())) {
            throw new BizException(ResultCode.CONFLICT, "Scrapped pallet must be retained and cannot be reused");
        }
        repository.deletePallet(id);
    }

    private void requireWarehouse(long customerId, long warehouseId) {
        warehouseDirectory.required(warehouseId);
    }

    private SharedWarehouseReference requireWarehouseReference(long warehouseId) {
        return warehouseDirectory.required(warehouseId);
    }

    private WarehouseLocationEntity requireLocation(long customerId, long warehouseId, long id) {
        requireWarehouse(customerId, warehouseId);
        WarehouseLocationEntity entity = repository.findLocation(customerId, warehouseId, id);
        if (entity == null) throw new BizException(ResultCode.NOT_FOUND, "当前仓库下库位不存在");
        return entity;
    }

    private WarehousePalletEntity requirePallet(long customerId, long warehouseId, long id) {
        requireWarehouse(customerId, warehouseId);
        WarehousePalletEntity entity = repository.findPallet(customerId, warehouseId, id);
        if (entity == null) throw new BizException(ResultCode.NOT_FOUND, "当前仓库下托盘不存在");
        return entity;
    }

    private void validateLocation(LocationRequests.SaveRequest request, long customerId,
                                  long warehouseId, Long excludedId) {
        if (!LOCATION_STATUSES.contains(request.status())) {
            throw new BizException("库位状态仅支持 ACTIVE、IDLE、OCCUPIED、INACTIVE");
        }
        if (repository.locationCodeExists(customerId, warehouseId, request.locationCode(), excludedId)) {
            throw new BizException(ResultCode.CONFLICT, "当前仓库下库位编码已存在");
        }
    }

    private void validatePallet(PalletRequests.SaveRequest request, String palletCode, Long locationId,
                                long customerId, long warehouseId, Long excludedId) {
        validatePalletStatus(request.status());
        if (repository.palletCodeExists(customerId, warehouseId, palletCode, excludedId)) {
            throw new BizException(ResultCode.CONFLICT, "当前仓库下托盘编码已存在");
        }
        if (locationId != null) {
            requireLocation(customerId, warehouseId, locationId);
        }
    }

    private void validatePalletStatus(String status) {
        if (!PALLET_STATUSES.contains(status)) {
            throw new BizException("托盘状态仅支持 IDLE、OCCUPIED、SCRAPPED");
        }
    }

    private WarehouseLocationEntity locationEntity(long customerId, long warehouseId,
                                                     LocationRequests.SaveRequest request) {
        WarehouseLocationEntity entity = new WarehouseLocationEntity();
        entity.setCustomerId(customerId);
        entity.setWarehouseId(warehouseId);
        entity.setZoneCode(request.zoneCode());
        entity.setLocationCode(request.locationCode());
        entity.setLocationType(request.locationType());
        entity.setMaxLoadKg(request.maxLoadKg());
        entity.setStatus(request.status());
        entity.setRemark(request.remark());
        return entity;
    }

    private WarehousePalletEntity palletEntity(long customerId, long warehouseId,
                                                 PalletRequests.SaveRequest request,
                                                 String palletCode, Long locationId) {
        WarehousePalletEntity entity = new WarehousePalletEntity();
        entity.setCustomerId(customerId);
        entity.setWarehouseId(warehouseId);
        entity.setLocationId(locationId);
        entity.setPalletCode(palletCode);
        entity.setPalletType(request.palletType());
        entity.setCapacityCbm(request.capacityCbm());
        entity.setUnitPrice(request.unitPrice());
        entity.setStatus(request.status());
        entity.setRemark(request.remark());
        entity.setFbaWarehouseCode(request.fbaWarehouseCode());
        return entity;
    }

    private static String generatedPalletCode(String warehouseCode, long palletId) {
        String boundedWarehouseCode = warehouseCode.length() <= 30 ? warehouseCode : warehouseCode.substring(0, 30);
        return "PLT-" + boundedWarehouseCode + "-" + LocalDate.now().format(DateTimeFormatter.BASIC_ISO_DATE)
            + "-" + Long.toUnsignedString(palletId);
    }

    private static String defaultLocationCode(String warehouseCode) {
        return "LOC-" + warehouseCode + "-DEFAULT";
    }
}