using Distribution.Features.Brand;
using Distribution.Features.Category;
using Distribution.Features.Uom;
using Distribution.Features.Item;
using Distribution.Infra.UoW;

namespace Distribution.Features.Sync;

public class SyncService(
    ICategoryRepository categoryRepo,
    ISubCategoryRepository subCategoryRepo,
    IBrandRepository brandRepo,
    IUomRepository uomRepo,
    IItemRepository itemRepo,
    IUnitOfWork uow)
{
    public async Task<SyncResult> SyncUomsAsync(SyncUomsPayload payload, CancellationToken ct = default)
    {
        int inserted = 0, updated = 0;
        await uow.BeginAsync(ct);
        try
        {
            foreach (var u in payload.Items)
            {
                var existing = await uomRepo.GetByExternalErpIdAsync(u.ErpId);
                if (existing is null)
                {
                    await uomRepo.AddAsync(new Models.Uom { Name = u.Name, ExternalErpId = u.ErpId });
                    inserted++;
                }
                else
                {
                    existing.Name = u.Name;
                    uomRepo.Update(existing);
                    updated++;
                }
            }
            await uow.CommitAsync(ct);
        }
        catch { await uow.RollbackAsync(ct); throw; }
        return new SyncResult(inserted, updated, 0);
    }

    public async Task<SyncResult> SyncCategoriesAsync(SyncCategoriesPayload payload, CancellationToken ct = default)
    {
        int inserted = 0, updated = 0;
        await uow.BeginAsync(ct);
        try
        {
            foreach (var c in payload.Items)
            {
                var existingCat = await categoryRepo.GetByExternalErpIdAsync(c.ErpId);
                Guid categoryId;
                if (existingCat is null)
                {
                    var newCat = new Models.Category { Name = c.Name, ExternalErpId = c.ErpId };
                    await categoryRepo.AddAsync(newCat);
                    categoryId = newCat.Id;
                    inserted++;
                }
                else
                {
                    existingCat.Name = c.Name;
                    categoryRepo.Update(existingCat);
                    categoryId = existingCat.Id;
                    updated++;
                }

                foreach (var s in c.SubCategories)
                {
                    var existingSub = await subCategoryRepo.GetByExternalErpIdAsync(s.ErpId);
                    if (existingSub is null)
                    {
                        await subCategoryRepo.AddAsync(new Models.SubCategory
                        {
                            Name = s.Name,
                            FK_CategoryId = categoryId,
                            ExternalErpId = s.ErpId
                        });
                        inserted++;
                    }
                    else
                    {
                        existingSub.Name = s.Name;
                        existingSub.FK_CategoryId = categoryId;
                        subCategoryRepo.Update(existingSub);
                        updated++;
                    }
                }
            }
            await uow.CommitAsync(ct);
        }
        catch { await uow.RollbackAsync(ct); throw; }
        return new SyncResult(inserted, updated, 0);
    }

    public async Task<SyncResult> SyncBrandsAsync(SyncBrandsPayload payload, CancellationToken ct = default)
    {
        int inserted = 0, updated = 0;
        await uow.BeginAsync(ct);
        try
        {
            foreach (var b in payload.Items)
            {
                var existing = await brandRepo.GetByExternalErpIdAsync(b.ErpId);
                if (existing is null)
                {
                    await brandRepo.AddAsync(new Models.Brand { Name = b.Name, ExternalErpId = b.ErpId });
                    inserted++;
                }
                else
                {
                    existing.Name = b.Name;
                    brandRepo.Update(existing);
                    updated++;
                }
            }
            await uow.CommitAsync(ct);
        }
        catch { await uow.RollbackAsync(ct); throw; }
        return new SyncResult(inserted, updated, 0);
    }

    public async Task<SyncResult> SyncItemsAsync(SyncItemsPayload payload, CancellationToken ct = default)
    {
        int inserted = 0, updated = 0, skipped = 0;
        await uow.BeginAsync(ct);
        try
        {
            foreach (var i in payload.Items)
            {
                var category = await categoryRepo.GetByExternalErpIdAsync(i.CategoryErpId);
                var baseUom = await uomRepo.GetByExternalErpIdAsync(i.BaseUomErpId);

                if (category is null || baseUom is null) { skipped++; continue; }

                Models.SubCategory? subCategory = null;
                if (i.SubCategoryErpId.HasValue)
                    subCategory = await subCategoryRepo.GetByExternalErpIdAsync(i.SubCategoryErpId.Value);

                Models.Brand? brand = null;
                if (i.BrandErpId.HasValue)
                    brand = await brandRepo.GetByExternalErpIdAsync(i.BrandErpId.Value);

                var existing = await itemRepo.GetByExternalErpItemIdAsync(i.ErpId);
                if (existing is null)
                {
                    await itemRepo.AddAsync(new Models.Item
                    {
                        Sku = i.Sku,
                        Name = i.Name,
                        Description = i.Description,
                        FK_CategoryId = category.Id,
                        FK_SubCategoryId = subCategory?.Id,
                        FK_BrandId = brand?.Id,
                        FK_BaseUomId = baseUom.Id,
                        SalePrice = i.SalePrice,
                        IsActive = i.IsActive,
                        SyncSource = Models.SyncSource.Erp,
                        ExternalErpItemId = i.ErpId,
                        LastSyncedAt = DateTime.UtcNow
                    });
                    inserted++;
                }
                else
                {
                    existing.Sku = i.Sku;
                    existing.Name = i.Name;
                    existing.Description = i.Description;
                    existing.FK_CategoryId = category.Id;
                    existing.FK_SubCategoryId = subCategory?.Id;
                    existing.FK_BrandId = brand?.Id;
                    existing.FK_BaseUomId = baseUom.Id;
                    existing.SalePrice = i.SalePrice;
                    existing.IsActive = i.IsActive;
                    existing.LastSyncedAt = DateTime.UtcNow;
                    itemRepo.Update(existing);
                    updated++;
                }
            }
            await uow.CommitAsync(ct);
        }
        catch { await uow.RollbackAsync(ct); throw; }
        return new SyncResult(inserted, updated, skipped);
    }
}