sales ,invoice ,slip and free issues BE fixes

Backend/ERPCore/Controllers/FreeIssuesController.cs

@@ -0,0 +1,78 @@
+using ERPCore.Domain.Enums;
+using ERPCore.Dtos.Common;
+using ERPCore.Dtos.Sales;
+using ERPCore.Services.Interfaces;
+using Microsoft.AspNetCore.Mvc;
+
+namespace ERPCore.Controllers;
+
+/// <summary>
+/// Thin API alias for free-issue handling. Free issues are modeled as sales slips
+/// with line-level <c>IsFreeIssue</c>/<c>FreeQty</c> flags, so this controller reuses
+/// the existing sales-slip CRUD surface under a more business-friendly route.
+/// </summary>
+[Route("api/v1/free-issues")]
+public sealed class FreeIssuesController : ApiControllerBase
+{
+    private readonly ISalesSlipService _slips;
+
+    public FreeIssuesController(ISalesSlipService slips) => _slips = slips;
+
+    [HttpGet]
+    [ProducesResponseType(typeof(PagedResponse<FreeIssueSummaryDto>), StatusCodes.Status200OK)]
+    public async Task<ActionResult<PagedResponse<FreeIssueSummaryDto>>> List(
+        [FromQuery] PageQuery query,
+        [FromQuery] SalesSlipStatus? status,
+        [FromQuery] int? customerId,
+        [FromQuery] int? warehouseId,
+        CancellationToken ct)
+        => Ok(await _slips.ListFreeIssuesAsync(query, status, customerId, warehouseId, ct));
+
+    [HttpGet("{freeIssueId:int}")]
+    [ProducesResponseType(typeof(FreeIssueDto), StatusCodes.Status200OK)]
+    [ProducesResponseType(StatusCodes.Status404NotFound)]
+    public async Task<ActionResult<FreeIssueDto>> GetById(int freeIssueId, CancellationToken ct)
+    {
+        var result = await _slips.GetFreeIssueAsync(freeIssueId, ct);
+        if (result is null) return NotFound();
+        SetETag(result.RowVersion);
+        return Ok(result.Value);
+    }
+
+    [HttpGet("{freeIssueId:int}/posting-check")]
+    [ProducesResponseType(typeof(SalesSlipPostingCheckDto), StatusCodes.Status200OK)]
+    [ProducesResponseType(StatusCodes.Status404NotFound)]
+    public async Task<ActionResult<SalesSlipPostingCheckDto>> PostingCheck(int freeIssueId, CancellationToken ct)
+        => Ok(await _slips.CheckPostingAsync(freeIssueId, ct));
+
+    [HttpPost]
+    [ProducesResponseType(typeof(FreeIssueDto), StatusCodes.Status201Created)]
+    public async Task<ActionResult<FreeIssueDto>> Create([FromBody] CreateSalesSlipRequest request, CancellationToken ct)
+    {
+        var result = await _slips.CreateAsync(request, ct);
+        SetETag(result.RowVersion);
+        return Created($"/api/v1/free-issues/{result.Value.SalesSlipId}", result.Value);
+    }
+
+    [HttpPut("{freeIssueId:int}")]
+    [ProducesResponseType(typeof(FreeIssueDto), StatusCodes.Status200OK)]
+    [ProducesResponseType(StatusCodes.Status404NotFound)]
+    [ProducesResponseType(StatusCodes.Status412PreconditionFailed)]
+    public async Task<ActionResult<FreeIssueDto>> Update(int freeIssueId, [FromBody] UpdateSalesSlipRequest request, CancellationToken ct)
+    {
+        var expected = RequireIfMatch();
+        var result = await _slips.UpdateAsync(freeIssueId, request, expected, ct);
+        SetETag(result.RowVersion);
+        return Ok(result.Value);
+    }
+
+    [HttpPost("{freeIssueId:int}/post")]
+    [ProducesResponseType(typeof(FreeIssueDto), StatusCodes.Status200OK)]
+    public async Task<ActionResult<FreeIssueDto>> Post(int freeIssueId, CancellationToken ct)
+        => Ok(await _slips.PostAsync(freeIssueId, ct));
+
+    [HttpPost("{freeIssueId:int}/cancel")]
+    [ProducesResponseType(typeof(FreeIssueDto), StatusCodes.Status200OK)]
+    public async Task<ActionResult<FreeIssueDto>> Cancel(int freeIssueId, CancellationToken ct)
+        => Ok(await _slips.CancelAsync(freeIssueId, ct));
+}

Backend/ERPCore/Controllers/SalesInvoicesController.cs

@@ -34,6 +34,12 @@ public sealed class SalesInvoicesController : ApiControllerBase
         return Ok(result.Value);
     }
 
+    [HttpGet("{salesInvoiceId:int}/posting-check")]
+    [ProducesResponseType(typeof(SalesInvoicePostingCheckDto), StatusCodes.Status200OK)]
+    [ProducesResponseType(StatusCodes.Status404NotFound)]
+    public async Task<ActionResult<SalesInvoicePostingCheckDto>> PostingCheck(int salesInvoiceId, CancellationToken ct)
+        => Ok(await _invoices.CheckPostingAsync(salesInvoiceId, ct));
+
     [HttpPost]
     [ProducesResponseType(typeof(SalesInvoiceDto), StatusCodes.Status201Created)]
     public async Task<ActionResult<SalesInvoiceDto>> Create([FromBody] CreateSalesInvoiceRequest request, CancellationToken ct)

Backend/ERPCore/Controllers/SalesReportsController.cs

@@ -11,39 +11,25 @@ public sealed class SalesReportsController : ApiControllerBase
 
     public SalesReportsController(ISalesReportService reports) => _reports = reports;
 
-    [HttpGet("daily-summary")]
+    [HttpGet]
-    [ProducesResponseType(typeof(IReadOnlyList<SalesDailySummaryRowDto>), StatusCodes.Status200OK)]
+    [ProducesResponseType(typeof(IReadOnlyList<SalesReportDefinitionDto>), StatusCodes.Status200OK)]
-    public async Task<ActionResult<IReadOnlyList<SalesDailySummaryRowDto>>> DailySummary(
+    public ActionResult<IReadOnlyList<SalesReportDefinitionDto>> ListReports()
-        [FromQuery] DateOnly from, [FromQuery] DateOnly to, CancellationToken ct)
+        => Ok(_reports.ListReports());
-        => Ok(await _reports.DailySummaryAsync(from, to, ct));
 
-    [HttpGet("item-wise")]
+    [HttpGet("{reportId}")]
-    [ProducesResponseType(typeof(IReadOnlyList<SalesItemSummaryRowDto>), StatusCodes.Status200OK)]
+    [ProducesResponseType(typeof(SalesReportDefinitionDto), StatusCodes.Status200OK)]
-    public async Task<ActionResult<IReadOnlyList<SalesItemSummaryRowDto>>> ItemWise(
+    [ProducesResponseType(StatusCodes.Status404NotFound)]
-        [FromQuery] DateOnly from, [FromQuery] DateOnly to, [FromQuery] int? itemId, [FromQuery] int? warehouseId, CancellationToken ct)
+    public ActionResult<SalesReportDefinitionDto> GetReport(string reportId)
-        => Ok(await _reports.ItemSummaryAsync(from, to, itemId, warehouseId, ct));
+    {
-
+        var report = _reports.GetReport(reportId);
-    [HttpGet("customer-wise")]
+        return report is null ? NotFound() : Ok(report);
-    [ProducesResponseType(typeof(IReadOnlyList<SalesCustomerSummaryRowDto>), StatusCodes.Status200OK)]
+    }
-    public async Task<ActionResult<IReadOnlyList<SalesCustomerSummaryRowDto>>> CustomerWise(
+
-        [FromQuery] DateOnly from, [FromQuery] DateOnly to, [FromQuery] int? customerId, CancellationToken ct)
+    [HttpPost("query")]
-        => Ok(await _reports.CustomerSummaryAsync(from, to, customerId, ct));
+    [ProducesResponseType(typeof(SalesReportQueryResponse), StatusCodes.Status200OK)]
-
+    public async Task<ActionResult<SalesReportQueryResponse>> Query([FromBody] SalesReportQueryRequest request, CancellationToken ct)
-    [HttpGet("warehouse-wise")]
+    {
-    [ProducesResponseType(typeof(IReadOnlyList<SalesWarehouseSummaryRowDto>), StatusCodes.Status200OK)]
+        var rows = await _reports.QueryAsync(request.ReportType, request.From, request.To, request.ItemId, request.CustomerId, request.WarehouseId, ct);
-    public async Task<ActionResult<IReadOnlyList<SalesWarehouseSummaryRowDto>>> WarehouseWise(
+        return Ok(new SalesReportQueryResponse(request.ReportType, request.From, request.To, rows));
-        [FromQuery] DateOnly from, [FromQuery] DateOnly to, [FromQuery] int? warehouseId, CancellationToken ct)
+    }
-        => Ok(await _reports.WarehouseSummaryAsync(from, to, warehouseId, ct));
-
-    [HttpGet("discount-summary")]
-    [ProducesResponseType(typeof(IReadOnlyList<SalesDiscountSummaryRowDto>), StatusCodes.Status200OK)]
-    public async Task<ActionResult<IReadOnlyList<SalesDiscountSummaryRowDto>>> DiscountSummary(
-        [FromQuery] DateOnly from, [FromQuery] DateOnly to, CancellationToken ct)
-        => Ok(await _reports.DiscountSummaryAsync(from, to, ct));
-
-    [HttpGet("free-issue-summary")]
-    [ProducesResponseType(typeof(IReadOnlyList<SalesFreeIssueSummaryRowDto>), StatusCodes.Status200OK)]
-    public async Task<ActionResult<IReadOnlyList<SalesFreeIssueSummaryRowDto>>> FreeIssueSummary(
-        [FromQuery] DateOnly from, [FromQuery] DateOnly to, CancellationToken ct)
-        => Ok(await _reports.FreeIssueSummaryAsync(from, to, ct));
 }

Backend/ERPCore/Controllers/SalesSlipPromotionsController.cs

@@ -0,0 +1,22 @@
+using ERPCore.Dtos.Sales;
+using ERPCore.Services.Interfaces;
+using Microsoft.AspNetCore.Mvc;
+
+namespace ERPCore.Controllers;
+
+[Route("api/v1/sales-slips/{salesSlipId:int}/free-issue-suggestions")]
+public sealed class SalesSlipPromotionsController : ApiControllerBase
+{
+    private readonly ISalesPromotionSuggestionService _suggestions;
+
+    public SalesSlipPromotionsController(ISalesPromotionSuggestionService suggestions) => _suggestions = suggestions;
+
+    [HttpGet]
+    [ProducesResponseType(typeof(SalesFreeIssueSuggestionDto), StatusCodes.Status200OK)]
+    [ProducesResponseType(StatusCodes.Status404NotFound)]
+    public async Task<ActionResult<SalesFreeIssueSuggestionDto>> Get(int salesSlipId, CancellationToken ct)
+    {
+        var result = await _suggestions.GetFreeIssueSuggestionsAsync(salesSlipId, ct);
+        return result is null ? NotFound() : Ok(result);
+    }
+}

Backend/ERPCore/Controllers/SalesSlipsController.cs

@@ -34,6 +34,12 @@ public sealed class SalesSlipsController : ApiControllerBase
         return Ok(result.Value);
     }
 
+    [HttpGet("{salesSlipId:int}/posting-check")]
+    [ProducesResponseType(typeof(SalesSlipPostingCheckDto), StatusCodes.Status200OK)]
+    [ProducesResponseType(StatusCodes.Status404NotFound)]
+    public async Task<ActionResult<SalesSlipPostingCheckDto>> PostingCheck(int salesSlipId, CancellationToken ct)
+        => Ok(await _slips.CheckPostingAsync(salesSlipId, ct));
+
     [HttpPost]
     [ProducesResponseType(typeof(SalesSlipDto), StatusCodes.Status201Created)]
     public async Task<ActionResult<SalesSlipDto>> Create([FromBody] CreateSalesSlipRequest request, CancellationToken ct)

Backend/ERPCore/Domain/Enums/SalesDiscountMode.cs

@@ -3,5 +3,5 @@ namespace ERPCore.Domain.Enums;
 public enum SalesDiscountMode
 {
     Percentage = 1,
-    FixedAmount = 2
+    Amount = 2
 }

Backend/ERPCore/Dtos/Sales/SalesInvoiceDtos.cs

@@ -24,6 +24,14 @@ public sealed record SalesInvoiceSummaryDto(
     string CustomerSnapshotName, int WarehouseId, SalesInvoiceType InvoiceType,
     SalesInvoiceStatus Status, SalesInvoiceTotalsDto Totals, DateTime CreatedAt);
 
+public sealed record SalesInvoicePostingIssueDto(
+    int SalesInvoiceLineId, int ItemId, string ItemSku, string ItemName, int WarehouseId,
+    decimal RequestedQty, decimal AvailableQty, decimal ShortQty, bool IsFreeIssue);
+
+public sealed record SalesInvoicePostingCheckDto(
+    int SalesInvoiceId, string InvoiceNo, SalesInvoiceStatus Status, bool CanPost,
+    IReadOnlyList<SalesInvoicePostingIssueDto> Issues);
+
 public sealed class CreateSalesInvoiceLineRequest
 {
     [Required] public int ItemId { get; set; }

Backend/ERPCore/Dtos/Sales/SalesPromotionSuggestionDtos.cs

@@ -0,0 +1,23 @@
+namespace ERPCore.Dtos.Sales;
+
+public sealed record SalesFreeIssueRewardOptionDto(
+    int ItemId,
+    string Sku,
+    string Name,
+    decimal? SalePrice);
+
+public sealed record SalesFreeIssueSuggestionLineDto(
+    int SalesSlipLineId,
+    int ItemId,
+    string ItemSku,
+    string ItemName,
+    decimal Qty,
+    decimal SuggestedFreeQty,
+    decimal TriggerQty,
+    IReadOnlyList<SalesFreeIssueRewardOptionDto> RewardOptions);
+
+public sealed record SalesFreeIssueSuggestionDto(
+    int SalesSlipId,
+    string SlipNo,
+    DateTime SlipDate,
+    IReadOnlyList<SalesFreeIssueSuggestionLineDto> Lines);

Backend/ERPCore/Dtos/Sales/SalesReportQueryDtos.cs

@@ -0,0 +1,21 @@
+namespace ERPCore.Dtos.Sales;
+
+public sealed record SalesReportDefinitionDto(
+    string Id,
+    string Name,
+    string Description,
+    IReadOnlyList<string> SupportedFilters);
+
+public sealed record SalesReportQueryRequest(
+    string ReportType,
+    DateOnly From,
+    DateOnly To,
+    int? ItemId = null,
+    int? CustomerId = null,
+    int? WarehouseId = null);
+
+public sealed record SalesReportQueryResponse(
+    string ReportType,
+    DateOnly From,
+    DateOnly To,
+    IReadOnlyList<object> Rows);

Backend/ERPCore/Dtos/Sales/SalesSlipDtos.cs

@@ -23,6 +23,25 @@ public sealed record SalesSlipSummaryDto(
     string CustomerSnapshotName, int WarehouseId, SalesSlipStatus Status,
     SalesSlipTotalsDto Totals, DateTime CreatedAt);
 
+public sealed record SalesSlipPostingIssueDto(
+    int SalesSlipLineId, int ItemId, string ItemSku, string ItemName, int WarehouseId,
+    decimal RequestedQty, decimal AvailableQty, decimal ShortQty, bool IsFreeIssue);
+
+public sealed record SalesSlipPostingCheckDto(
+    int SalesSlipId, string SlipNo, SalesSlipStatus Status, bool CanPost,
+    IReadOnlyList<SalesSlipPostingIssueDto> Issues);
+
+public sealed record FreeIssueSummaryDto(
+    int SalesSlipId, string SlipNo, SalesSlipStatus Status, DateTime CreatedAt,
+    int WarehouseId, string WarehouseName, int ItemId, string ItemSku, string ItemName,
+    int UomId, string UomName, decimal Qty, decimal FreeQty, string SchemeLabel);
+
+public sealed record FreeIssueDto(
+    int SalesSlipId, string SlipNo, DateTime SlipDate, SalesSlipStatus Status,
+    int CustomerId, string CustomerSnapshotName, int WarehouseId, string WarehouseName,
+    int CashierUserId, DateTime CreatedAt, DateTime? UpdatedAt, FreeIssueSummaryDto Summary,
+    IReadOnlyList<SalesSlipLineDto> Lines);
+
 public sealed class CreateSalesSlipLineRequest
 {
     [Required] public int ItemId { get; set; }

Backend/ERPCore/Services/Interfaces/ISalesInvoiceService.cs

@@ -9,6 +9,7 @@ public interface ISalesInvoiceService
 {
     Task<PagedResponse<SalesInvoiceSummaryDto>> ListAsync(PageQuery query, SalesInvoiceStatus? status, int? customerId, int? warehouseId, CancellationToken ct = default);
     Task<ETagged<SalesInvoiceDto>?> GetAsync(int salesInvoiceId, CancellationToken ct = default);
+    Task<SalesInvoicePostingCheckDto> CheckPostingAsync(int salesInvoiceId, CancellationToken ct = default);
     Task<ETagged<SalesInvoiceDto>> CreateAsync(CreateSalesInvoiceRequest request, CancellationToken ct = default);
     Task<ETagged<SalesInvoiceDto>> UpdateAsync(int salesInvoiceId, UpdateSalesInvoiceRequest request, uint expectedRowVersion, CancellationToken ct = default);
     Task<SalesInvoiceDto> PostAsync(int salesInvoiceId, CancellationToken ct = default);

Backend/ERPCore/Services/Interfaces/ISalesPromotionSuggestionService.cs

@@ -0,0 +1,8 @@
+using ERPCore.Dtos.Sales;
+
+namespace ERPCore.Services.Interfaces;
+
+public interface ISalesPromotionSuggestionService
+{
+    Task<SalesFreeIssueSuggestionDto?> GetFreeIssueSuggestionsAsync(int salesSlipId, CancellationToken ct = default);
+}

Backend/ERPCore/Services/Interfaces/ISalesReportService.cs

@@ -4,6 +4,9 @@ namespace ERPCore.Services.Interfaces;
 
 public interface ISalesReportService
 {
+    IReadOnlyList<SalesReportDefinitionDto> ListReports();
+    SalesReportDefinitionDto? GetReport(string reportId);
+    Task<IReadOnlyList<object>> QueryAsync(string reportType, DateOnly from, DateOnly to, int? itemId, int? customerId, int? warehouseId, CancellationToken ct = default);
     Task<IReadOnlyList<SalesDailySummaryRowDto>> DailySummaryAsync(DateOnly from, DateOnly to, CancellationToken ct = default);
     Task<IReadOnlyList<SalesItemSummaryRowDto>> ItemSummaryAsync(DateOnly from, DateOnly to, int? itemId, int? warehouseId, CancellationToken ct = default);
     Task<IReadOnlyList<SalesCustomerSummaryRowDto>> CustomerSummaryAsync(DateOnly from, DateOnly to, int? customerId, CancellationToken ct = default);

Backend/ERPCore/Services/Interfaces/ISalesSlipService.cs

@@ -9,6 +9,9 @@ public interface ISalesSlipService
 {
     Task<PagedResponse<SalesSlipSummaryDto>> ListAsync(PageQuery query, SalesSlipStatus? status, int? customerId, int? warehouseId, CancellationToken ct = default);
     Task<ETagged<SalesSlipDto>?> GetAsync(int salesSlipId, CancellationToken ct = default);
+    Task<PagedResponse<FreeIssueSummaryDto>> ListFreeIssuesAsync(PageQuery query, SalesSlipStatus? status, int? customerId, int? warehouseId, CancellationToken ct = default);
+    Task<ETagged<FreeIssueDto>?> GetFreeIssueAsync(int salesSlipId, CancellationToken ct = default);
+    Task<SalesSlipPostingCheckDto> CheckPostingAsync(int salesSlipId, CancellationToken ct = default);
     Task<ETagged<SalesSlipDto>> CreateAsync(CreateSalesSlipRequest request, CancellationToken ct = default);
     Task<ETagged<SalesSlipDto>> UpdateAsync(int salesSlipId, UpdateSalesSlipRequest request, uint expectedRowVersion, CancellationToken ct = default);
     Task<SalesSlipDto> PostAsync(int salesSlipId, CancellationToken ct = default);

Backend/ERPCore/Services/SalesInvoiceService.cs

@@ -69,6 +69,41 @@ public sealed class SalesInvoiceService : ISalesInvoiceService
         return invoice is null ? null : new ETagged<SalesInvoiceDto>(Map(invoice), invoice.RowVersion);
     }
 
+    public async Task<SalesInvoicePostingCheckDto> CheckPostingAsync(int salesInvoiceId, CancellationToken ct = default)
+    {
+        var invoice = await _invoices.Query().AsNoTracking().Include(x => x.Lines)
+            .FirstOrDefaultAsync(x => x.SalesInvoiceId == salesInvoiceId, ct)
+            ?? throw new NotFoundException($"Sales invoice {salesInvoiceId} was not found.");
+
+        if (invoice.Status != SalesInvoiceStatus.Draft)
+            return new SalesInvoicePostingCheckDto(invoice.SalesInvoiceId, invoice.InvoiceNo, invoice.Status, false, Array.Empty<SalesInvoicePostingIssueDto>());
+
+        var issues = new List<SalesInvoicePostingIssueDto>();
+        foreach (var line in invoice.Lines)
+        {
+            var requestedQty = line.Qty + line.FreeQty;
+            var available = await _fifo.GetOnHandAsync(line.ItemId, line.WarehouseId, ct);
+            if (available >= requestedQty) continue;
+
+            var item = await _items.Query().AsNoTracking()
+                .Where(x => x.ItemId == line.ItemId)
+                .Select(x => new { x.Sku, x.Name })
+                .FirstAsync(ct);
+            issues.Add(new SalesInvoicePostingIssueDto(
+                line.SalesInvoiceLineId,
+                line.ItemId,
+                item.Sku,
+                item.Name,
+                line.WarehouseId,
+                requestedQty,
+                available,
+                requestedQty - available,
+                line.IsFreeIssue));
+        }
+
+        return new SalesInvoicePostingCheckDto(invoice.SalesInvoiceId, invoice.InvoiceNo, invoice.Status, issues.Count == 0, issues);
+    }
+
     public async Task<ETagged<SalesInvoiceDto>> CreateAsync(CreateSalesInvoiceRequest request, CancellationToken ct = default)
     {
         await ValidateReferencesAsync(request.CustomerId, request.WarehouseId, request.Lines, ct);
@@ -228,7 +263,7 @@ public sealed class SalesInvoiceService : ISalesInvoiceService
 
     private static decimal CalculateDiscount(decimal gross, SalesDiscountMode mode, decimal discountPct, decimal discountValue, decimal legacyDiscountAmount)
     {
-        var computed = mode == SalesDiscountMode.FixedAmount
+        var computed = mode == SalesDiscountMode.Amount
             ? discountValue
             : gross * (discountPct / 100m);
 

Backend/ERPCore/Services/SalesPromotionSuggestionService.cs

@@ -0,0 +1,74 @@
+using ERPCore.Domain.Entities;
+using ERPCore.Domain.Enums;
+using ERPCore.Dtos.Sales;
+using ERPCore.Repositories.Interfaces;
+using ERPCore.Services.Interfaces;
+using Microsoft.EntityFrameworkCore;
+
+namespace ERPCore.Services;
+
+public sealed class SalesPromotionSuggestionService : ISalesPromotionSuggestionService
+{
+    private const decimal FreeIssueThreshold = 10m;
+
+    private readonly IRepository<SalesSlip> _slips;
+    private readonly IRepository<Item> _items;
+
+    public SalesPromotionSuggestionService(IRepository<SalesSlip> slips, IRepository<Item> items)
+    {
+        _slips = slips;
+        _items = items;
+    }
+
+    public async Task<SalesFreeIssueSuggestionDto?> GetFreeIssueSuggestionsAsync(int salesSlipId, CancellationToken ct = default)
+    {
+        var slip = await _slips.Query().AsNoTracking().Include(x => x.Lines)
+            .FirstOrDefaultAsync(x => x.SalesSlipId == salesSlipId, ct);
+
+        if (slip is null) return null;
+
+        var itemIds = slip.Lines.Select(x => x.ItemId).Distinct().ToList();
+        var candidateItems = await _items.Query().AsNoTracking()
+            .Where(x => itemIds.Contains(x.ItemId) && x.Status == EntityStatus.Active)
+            .ToListAsync(ct);
+
+        var byItemId = candidateItems.ToDictionary(x => x.ItemId);
+        var suggestions = new List<SalesFreeIssueSuggestionLineDto>();
+
+        foreach (var line in slip.Lines.Where(x => x.Qty >= FreeIssueThreshold))
+        {
+            if (!byItemId.TryGetValue(line.ItemId, out var item)) continue;
+
+            var freeQty = Math.Floor(line.Qty / FreeIssueThreshold);
+            if (freeQty <= 0m) continue;
+
+            var rewardOptions = new List<SalesFreeIssueRewardOptionDto>
+            {
+                new(item.ItemId, item.Sku, item.Name, item.SalePrice)
+            };
+
+            var alternates = await _items.Query().AsNoTracking()
+                .Where(x => x.Status == EntityStatus.Active && x.CategoryId == item.CategoryId && x.ItemId != item.ItemId)
+                .OrderBy(x => x.Name)
+                .Take(3)
+                .Select(x => new SalesFreeIssueRewardOptionDto(x.ItemId, x.Sku, x.Name, x.SalePrice))
+                .ToListAsync(ct);
+
+            rewardOptions.AddRange(alternates.Where(x => rewardOptions.All(r => r.ItemId != x.ItemId)));
+
+            suggestions.Add(new SalesFreeIssueSuggestionLineDto(
+                line.SalesSlipLineId,
+                item.ItemId,
+                item.Sku,
+                item.Name,
+                line.Qty,
+                freeQty,
+                FreeIssueThreshold,
+                rewardOptions));
+        }
+
+        return suggestions.Count == 0
+            ? new SalesFreeIssueSuggestionDto(slip.SalesSlipId, slip.SlipNo, slip.SlipDate, Array.Empty<SalesFreeIssueSuggestionLineDto>())
+            : new SalesFreeIssueSuggestionDto(slip.SalesSlipId, slip.SlipNo, slip.SlipDate, suggestions);
+    }
+}

Backend/ERPCore/Services/SalesReportService.cs

@@ -3,12 +3,23 @@ using ERPCore.Domain.Enums;
 using ERPCore.Dtos.Sales;
 using ERPCore.Repositories.Interfaces;
 using ERPCore.Services.Interfaces;
+using ERPCore.System.Errors;
 using Microsoft.EntityFrameworkCore;
 
 namespace ERPCore.Services;
 
 public sealed class SalesReportService : ISalesReportService
 {
+    private static readonly SalesReportDefinitionDto[] ReportDefinitions =
+    [
+        new("daily-summary", "Daily Summary", "Aggregated sales by day across posted invoices and slips.", ["from", "to"]),
+        new("item-summary", "Item Summary", "Aggregated sales by item across posted invoices and slips.", ["from", "to", "itemId", "warehouseId"]),
+        new("customer-summary", "Customer Summary", "Aggregated sales by customer across posted invoices and slips.", ["from", "to", "customerId"]),
+        new("warehouse-summary", "Warehouse Summary", "Aggregated sales by warehouse across posted invoices and slips.", ["from", "to", "warehouseId"]),
+        new("discount-summary", "Discount Summary", "Documents with discounts applied.", ["from", "to"]),
+        new("free-issue-summary", "Free Issue Summary", "Lines with free quantities issued.", ["from", "to"])
+    ];
+
     private readonly IRepository<SalesInvoice> _invoices;
     private readonly IRepository<SalesSlip> _slips;
 
@@ -18,6 +29,54 @@ public sealed class SalesReportService : ISalesReportService
         _slips = slips;
     }
 
+    public IReadOnlyList<SalesReportDefinitionDto> ListReports() => ReportDefinitions;
+
+    public SalesReportDefinitionDto? GetReport(string reportId)
+    {
+        var normalized = reportId.Trim().ToLowerInvariant();
+        return ReportDefinitions.FirstOrDefault(r => r.Id == normalized);
+    }
+
+    public async Task<IReadOnlyList<object>> QueryAsync(string reportType, DateOnly from, DateOnly to, int? itemId, int? customerId, int? warehouseId, CancellationToken ct = default)
+    {
+        var normalized = reportType.Trim().ToLowerInvariant();
+        ValidateFilters(normalized, itemId, customerId, warehouseId);
+
+        return normalized switch
+        {
+            "daily" or "daily-summary" => (await DailySummaryAsync(from, to, ct)).Cast<object>().ToList(),
+            "item" or "item-summary" or "item-wise" => (await ItemSummaryAsync(from, to, itemId, warehouseId, ct)).Cast<object>().ToList(),
+            "customer" or "customer-summary" or "customer-wise" => (await CustomerSummaryAsync(from, to, customerId, ct)).Cast<object>().ToList(),
+            "warehouse" or "warehouse-summary" or "warehouse-wise" => (await WarehouseSummaryAsync(from, to, warehouseId, ct)).Cast<object>().ToList(),
+            "discount" or "discount-summary" => (await DiscountSummaryAsync(from, to, ct)).Cast<object>().ToList(),
+            "free-issue" or "free-issue-summary" => (await FreeIssueSummaryAsync(from, to, ct)).Cast<object>().ToList(),
+            _ => throw new DomainException("INVALID_REPORT_TYPE", $"Unsupported sales report type '{reportType}'.", 400)
+        };
+    }
+
+    private static void ValidateFilters(string reportType, int? itemId, int? customerId, int? warehouseId)
+    {
+        var allowed = reportType switch
+        {
+            "daily" or "daily-summary" => new FilterSet(false, false, false),
+            "item" or "item-summary" or "item-wise" => new FilterSet(true, false, true),
+            "customer" or "customer-summary" or "customer-wise" => new FilterSet(false, true, false),
+            "warehouse" or "warehouse-summary" or "warehouse-wise" => new FilterSet(false, false, true),
+            "discount" or "discount-summary" => new FilterSet(false, false, false),
+            "free-issue" or "free-issue-summary" => new FilterSet(false, false, false),
+            _ => throw new DomainException("INVALID_REPORT_TYPE", $"Unsupported sales report type '{reportType}'.", 400)
+        };
+
+        if (!allowed.Item && itemId is not null)
+            throw new DomainException("INVALID_REPORT_FILTER", $"Filter 'itemId' is not valid for report type '{reportType}'.", 400);
+        if (!allowed.Customer && customerId is not null)
+            throw new DomainException("INVALID_REPORT_FILTER", $"Filter 'customerId' is not valid for report type '{reportType}'.", 400);
+        if (!allowed.Warehouse && warehouseId is not null)
+            throw new DomainException("INVALID_REPORT_FILTER", $"Filter 'warehouseId' is not valid for report type '{reportType}'.", 400);
+    }
+
+    private readonly record struct FilterSet(bool Item, bool Customer, bool Warehouse);
+
     public async Task<IReadOnlyList<SalesDailySummaryRowDto>> DailySummaryAsync(DateOnly from, DateOnly to, CancellationToken ct = default)
     {
         var invoiceRows = await _invoices.Query().AsNoTracking()
@@ -72,10 +131,9 @@ public sealed class SalesReportService : ISalesReportService
 
     public async Task<IReadOnlyList<SalesItemSummaryRowDto>> ItemSummaryAsync(DateOnly from, DateOnly to, int? itemId, int? warehouseId, CancellationToken ct = default)
     {
-        var invoiceLines = _invoices.Query().AsNoTracking()
+        var invoiceRows = await _invoices.Query().AsNoTracking()
-            .Where(x => x.Status == SalesInvoiceStatus.Posted && x.InvoiceDate >= from.ToDateTime(TimeOnly.MinValue) && x.InvoiceDate < to.AddDays(1).ToDateTime(TimeOnly.MinValue));
+            .Where(x => x.Status == SalesInvoiceStatus.Posted && x.InvoiceDate >= from.ToDateTime(TimeOnly.MinValue) && x.InvoiceDate < to.AddDays(1).ToDateTime(TimeOnly.MinValue))
-        if (warehouseId is not null) invoiceLines = invoiceLines.Where(x => x.WarehouseId == warehouseId);
+            .SelectMany(x => x.Lines.Select(l => new
-        var invoiceQuery = invoiceLines.SelectMany(x => x.Lines.Select(l => new
             {
                 l.ItemId,
                 l.Description,
@@ -85,14 +143,18 @@ public sealed class SalesReportService : ISalesReportService
                 l.DiscountAmount,
                 l.TaxAmount,
                 l.LineTotal,
-            l.WarehouseId
+                x.WarehouseId
-        }));
+            }))
-        if (itemId is not null) invoiceQuery = invoiceQuery.Where(x => x.ItemId == itemId);
+            .ToListAsync(ct);
 
-        var slipLines = _slips.Query().AsNoTracking()
+        if (warehouseId is not null)
-            .Where(x => x.Status == SalesSlipStatus.Posted && x.SlipDate >= from.ToDateTime(TimeOnly.MinValue) && x.SlipDate < to.AddDays(1).ToDateTime(TimeOnly.MinValue));
+            invoiceRows = invoiceRows.Where(x => x.WarehouseId == warehouseId).ToList();
-        if (warehouseId is not null) slipLines = slipLines.Where(x => x.WarehouseId == warehouseId);
+        if (itemId is not null)
-        var slipQuery = slipLines.SelectMany(x => x.Lines.Select(l => new
+            invoiceRows = invoiceRows.Where(x => x.ItemId == itemId).ToList();
+
+        var slipRows = await _slips.Query().AsNoTracking()
+            .Where(x => x.Status == SalesSlipStatus.Posted && x.SlipDate >= from.ToDateTime(TimeOnly.MinValue) && x.SlipDate < to.AddDays(1).ToDateTime(TimeOnly.MinValue))
+            .SelectMany(x => x.Lines.Select(l => new
             {
                 l.ItemId,
                 l.Description,
@@ -102,12 +164,18 @@ public sealed class SalesReportService : ISalesReportService
                 l.DiscountAmount,
                 l.TaxAmount,
                 l.LineTotal,
-            l.WarehouseId
+                x.WarehouseId
-        }));
+            }))
-        if (itemId is not null) slipQuery = slipQuery.Where(x => x.ItemId == itemId);
+            .ToListAsync(ct);
 
-        var rows = await invoiceQuery.Concat(slipQuery)
+        if (warehouseId is not null)
+            slipRows = slipRows.Where(x => x.WarehouseId == warehouseId).ToList();
+        if (itemId is not null)
+            slipRows = slipRows.Where(x => x.ItemId == itemId).ToList();
+
+        return invoiceRows.Concat(slipRows)
             .GroupBy(x => new { x.ItemId, x.Description })
+            .OrderByDescending(g => g.Sum(x => x.LineTotal) + g.Sum(x => x.TaxAmount))
             .Select(g => new SalesItemSummaryRowDto(
                 g.Key.ItemId,
                 g.Key.Description,
@@ -116,11 +184,8 @@ public sealed class SalesReportService : ISalesReportService
                 g.Sum(x => x.Gross),
                 g.Sum(x => x.DiscountAmount),
                 g.Sum(x => x.TaxAmount),
-                g.Sum(x => x.LineTotal + x.TaxAmount)))
+                g.Sum(x => x.LineTotal) + g.Sum(x => x.TaxAmount)))
-            .OrderByDescending(x => x.NetAmount)
+            .ToList();
-            .ToListAsync(ct);
-
-        return rows;
     }
 
     public async Task<IReadOnlyList<SalesCustomerSummaryRowDto>> CustomerSummaryAsync(DateOnly from, DateOnly to, int? customerId, CancellationToken ct = default)

Backend/ERPCore/Services/SalesSlipService.cs

@@ -70,6 +70,66 @@ public sealed class SalesSlipService : ISalesSlipService
         return slip is null ? null : new ETagged<SalesSlipDto>(Map(slip), slip.RowVersion);
     }
 
+    public async Task<PagedResponse<FreeIssueSummaryDto>> ListFreeIssuesAsync(PageQuery query, SalesSlipStatus? status, int? customerId, int? warehouseId, CancellationToken ct = default)
+    {
+        IQueryable<SalesSlip> q = _slips.Query().AsNoTracking().Include(x => x.Lines);
+        q = q.Where(x => x.Lines.Any(l => l.IsFreeIssue || l.FreeQty > 0m));
+        if (!string.IsNullOrWhiteSpace(query.Q))
+        {
+            var term = query.Q.Trim();
+            q = q.Where(x => EF.Functions.ILike(x.SlipNo, $"%{term}%") || EF.Functions.ILike(x.CustomerSnapshotName, $"%{term}%"));
+        }
+        if (status is not null) q = q.Where(x => x.Status == status);
+        if (customerId is not null) q = q.Where(x => x.CustomerId == customerId);
+        if (warehouseId is not null) q = q.Where(x => x.WarehouseId == warehouseId);
+
+        var total = await q.CountAsync(ct);
+        var rows = await q.OrderByDescending(x => x.SalesSlipId).Skip(query.Skip).Take(query.PageSize).ToListAsync(ct);
+        return PagedResponse<FreeIssueSummaryDto>.Create(rows.Select(MapFreeIssueSummary).ToList(), query.Page, query.PageSize, total);
+    }
+
+    public async Task<ETagged<FreeIssueDto>?> GetFreeIssueAsync(int salesSlipId, CancellationToken ct = default)
+    {
+        var slip = await _slips.Query().AsNoTracking().Include(x => x.Lines)
+            .FirstOrDefaultAsync(x => x.SalesSlipId == salesSlipId, ct);
+        return slip is null ? null : new ETagged<FreeIssueDto>(MapFreeIssue(slip), slip.RowVersion);
+    }
+
+    public async Task<SalesSlipPostingCheckDto> CheckPostingAsync(int salesSlipId, CancellationToken ct = default)
+    {
+        var slip = await _slips.Query().AsNoTracking().Include(x => x.Lines)
+            .FirstOrDefaultAsync(x => x.SalesSlipId == salesSlipId, ct)
+            ?? throw new NotFoundException($"Sales slip {salesSlipId} was not found.");
+
+        if (slip.Status != SalesSlipStatus.Draft)
+            return new SalesSlipPostingCheckDto(slip.SalesSlipId, slip.SlipNo, slip.Status, false, Array.Empty<SalesSlipPostingIssueDto>());
+
+        var issues = new List<SalesSlipPostingIssueDto>();
+        foreach (var line in slip.Lines)
+        {
+            var requestedQty = line.Qty + line.FreeQty;
+            var available = await _fifo.GetOnHandAsync(line.ItemId, line.WarehouseId, ct);
+            if (available >= requestedQty) continue;
+
+            var item = await _items.Query().AsNoTracking()
+                .Where(x => x.ItemId == line.ItemId)
+                .Select(x => new { x.Sku, x.Name })
+                .FirstAsync(ct);
+            issues.Add(new SalesSlipPostingIssueDto(
+                line.SalesSlipLineId,
+                line.ItemId,
+                item.Sku,
+                item.Name,
+                line.WarehouseId,
+                requestedQty,
+                available,
+                requestedQty - available,
+                line.IsFreeIssue));
+        }
+
+        return new SalesSlipPostingCheckDto(slip.SalesSlipId, slip.SlipNo, slip.Status, issues.Count == 0, issues);
+    }
+
     public async Task<ETagged<SalesSlipDto>> CreateAsync(CreateSalesSlipRequest request, CancellationToken ct = default)
     {
         await ValidateReferencesAsync(request.CustomerId, request.WarehouseId, request.CashierUserId, request.Lines, ct);
@@ -227,7 +287,7 @@ public sealed class SalesSlipService : ISalesSlipService
 
     private static decimal CalculateDiscount(decimal gross, SalesDiscountMode mode, decimal discountPct, decimal discountValue, decimal legacyDiscountAmount)
     {
-        var computed = mode == SalesDiscountMode.FixedAmount
+        var computed = mode == SalesDiscountMode.Amount
             ? discountValue
             : gross * (discountPct / 100m);
 
@@ -241,6 +301,57 @@ public sealed class SalesSlipService : ISalesSlipService
         x.SalesSlipId, x.SlipNo, x.SlipDate, x.CustomerId, x.CustomerSnapshotName, x.WarehouseId, x.Status,
         new SalesSlipTotalsDto(x.Subtotal, x.DiscountTotal, x.Lines.Sum(l => l.FreeQty), x.TaxTotal, x.GrandTotal, x.PaidAmount, x.BalanceAmount), x.CreatedAt);
 
+    private FreeIssueSummaryDto MapFreeIssueSummary(SalesSlip x)
+    {
+        var line = x.Lines.FirstOrDefault();
+        var item = line is null ? null : _items.Query().AsNoTracking()
+            .Where(i => i.ItemId == line.ItemId)
+            .Select(i => new { i.ItemId, i.Sku, i.Name, i.BaseUomId })
+            .FirstOrDefault();
+        var uom = line is null ? null : _uoms.Query().AsNoTracking()
+            .Where(u => u.UomId == line.UomId)
+            .Select(u => new { u.UomId, u.Name })
+            .FirstOrDefault();
+        var warehouse = _warehouses.Query().AsNoTracking()
+            .Where(w => w.WarehouseId == x.WarehouseId)
+            .Select(w => new { w.WarehouseId, w.Name })
+            .FirstOrDefault();
+        return new FreeIssueSummaryDto(
+            x.SalesSlipId,
+            x.SlipNo,
+            x.Status,
+            x.CreatedAt,
+            x.WarehouseId,
+            warehouse?.Name ?? $"Warehouse {x.WarehouseId}",
+            line?.ItemId ?? 0,
+            item?.Sku ?? $"SKU-{line?.ItemId ?? 0}",
+            item?.Name ?? line?.Description ?? "—",
+            line?.UomId ?? 0,
+            uom?.Name ?? $"UOM {line?.UomId ?? 0}",
+            line?.Qty ?? 0m,
+            line?.FreeQty ?? 0m,
+            line is null ? "No line" : $"Buy {line.Qty} Get {line.FreeQty}");
+    }
+
+    private FreeIssueDto MapFreeIssue(SalesSlip x)
+    {
+        var summary = MapFreeIssueSummary(x);
+        return new FreeIssueDto(
+            x.SalesSlipId,
+            x.SlipNo,
+            x.SlipDate,
+            x.Status,
+            x.CustomerId,
+            x.CustomerSnapshotName,
+            x.WarehouseId,
+            summary.WarehouseName,
+            x.CashierUserId,
+            x.CreatedAt,
+            x.UpdatedAt,
+            summary,
+            x.Lines.Select(l => new SalesSlipLineDto(l.SalesSlipLineId, l.ItemId, l.Description, l.Qty, l.FreeQty, l.UomId, l.WarehouseId, l.UnitPrice, l.BaseCost, l.PriceSource, l.DiscountPct, l.DiscountAmount, l.DiscountMode, l.NetUnitPrice, l.LineTotal, l.TaxPct, l.TaxAmount, l.IsFreeIssue, l.ParentLineId)).ToList());
+    }
+
     private static SalesSlipDto Map(SalesSlip x) => new(
         x.SalesSlipId, x.SlipNo, x.SlipDate, x.CustomerId, x.CustomerSnapshotName, x.WarehouseId, x.CashierUserId, x.Status, x.CreatedAt, x.UpdatedAt,
         new SalesSlipTotalsDto(x.Subtotal, x.DiscountTotal, x.Lines.Sum(l => l.FreeQty), x.TaxTotal, x.GrandTotal, x.PaidAmount, x.BalanceAmount),