using Dapper;
using JdeScoping.DataAccess.Interfaces;
using Microsoft.Data.SqlClient;
using Microsoft.Extensions.Logging;

namespace JdeScoping.DataAccess.Services;

/// <summary>
/// Service for traversing downstream work orders iteratively.
/// </summary>
public sealed class WorkOrderTraversalService : IWorkOrderTraversalService
{
    private readonly ILogger<WorkOrderTraversalService> _logger;

    /// <summary>
    /// Initializes a new instance of WorkOrderTraversalService.
    /// </summary>
    /// <param name="logger">The logger.</param>
    public WorkOrderTraversalService(ILogger<WorkOrderTraversalService> logger)
    {
        _logger = logger;
    }

    /// <inheritdoc />
    public async Task TraverseDownstreamAsync(
        SqlConnection connection,
        int maxIterations = 20,
        CancellationToken ct = default)
    {
        _logger.LogDebug("Starting downstream work order traversal (max {MaxIterations} iterations)", maxIterations);

        // The traversal SQL iteratively finds work orders that received material from flagged work orders
        const string traversalSql = """
            --Add downlevel work orders that were issued material from flagged work orders
            DECLARE @c_MAX_RUNS INT = @p_MaxIterations;
            DECLARE @v_NumWO INT = -1;
            DECLARE @v_NewNumWO INT;
            DECLARE @v_NumRuns INT = 0;

            WHILE(1 = 1) BEGIN
                SET @v_NumWO = @v_NewNumWO;

                --Add any work orders issued material from flagged work orders (parts list)
                WITH CWO_D AS(
                    SELECT DISTINCT wo.WorkOrderNumber,
                           wo.LotNumber,
                           wo.BranchCode,
                           wo.ShortItemNumber
                    FROM   dbo.WorkOrderComponent AS woc INNER JOIN
                           dbo.WorkOrder AS wo ON (woc.WorkOrderNumber = wo.WorkOrderNumber) INNER JOIN
                           #Temp_WO AS t_wo ON (woc.LotNumber = t_wo.LotNumber AND woc.ShortItemNumber = t_wo.ShortItemNumber)
                )
                MERGE #Temp_WO AS TARGET
                USING CWO_D AS SOURCE
                ON    (TARGET.WorkOrderNumber = SOURCE.WorkOrderNumber)
                WHEN  MATCHED THEN
                    UPDATE SET TARGET.PartsList = 1
                WHEN  NOT MATCHED THEN
                    INSERT (WorkOrderNumber, LotNumber, BranchCode, ShortItemNumber, PartsList)
                    VALUES (SOURCE.WorkOrderNumber, COALESCE(SOURCE.LotNumber, CAST(SOURCE.WorkOrderNumber AS VARCHAR(8))), SOURCE.BranchCode, SOURCE.ShortItemNumber, 1);

                --Add any work orders issued material from flagged work orders (CARDEX)
                WITH CWO_D AS(
                    SELECT DISTINCT wo.WorkOrderNumber,
                           wo.LotNumber,
                           wo.BranchCode,
                           wo.ShortItemNumber
                    FROM   dbo.LotUsage AS lu INNER JOIN
                           dbo.WorkOrder AS wo ON (lu.WorkOrderNumber = wo.WorkOrderNumber) INNER JOIN
                           #Temp_WO AS t_wo ON (lu.LotNumber = t_wo.LotNumber AND lu.ShortItemNumber = t_wo.ShortItemNumber)
                )
                MERGE #Temp_WO AS TARGET
                USING CWO_D AS SOURCE
                ON    (TARGET.WorkOrderNumber = SOURCE.WorkOrderNumber)
                WHEN  MATCHED THEN
                    UPDATE SET TARGET.CARDEX = 1
                WHEN  NOT MATCHED THEN
                    INSERT (WorkOrderNumber, LotNumber, BranchCode, ShortItemNumber, CARDEX)
                    VALUES (SOURCE.WorkOrderNumber, COALESCE(SOURCE.LotNumber, CAST(SOURCE.WorkOrderNumber AS VARCHAR(8))), SOURCE.BranchCode, SOURCE.ShortItemNumber, 1);

                --Add any work orders split from flagged work orders
                WITH SP_WO AS
                (
                    SELECT DISTINCT wo.WorkOrderNumber,
                           wo.LotNumber,
                           wo.BranchCode,
                           wo.ShortItemNumber
                    FROM   dbo.WorkOrder AS wo INNER JOIN
                           #Temp_WO AS tw_o ON (wo.ParentWorkOrderNumber = CAST(tw_o.WorkOrderNumber AS VARCHAR(8)) AND wo.BranchCode = tw_o.BranchCode)
                )
                MERGE #Temp_WO AS TARGET
                USING SP_WO AS SOURCE
                ON    (TARGET.WorkOrderNumber = SOURCE.WorkOrderNumber AND TARGET.BranchCode = SOURCE.BranchCode)
                WHEN  MATCHED THEN
                    UPDATE SET TARGET.SplitOrder = 1
                WHEN NOT MATCHED BY TARGET THEN
                    INSERT (WorkOrderNumber, LotNumber, BranchCode, ShortItemNumber, SplitOrder)
                    VALUES (SOURCE.WorkOrderNumber, SOURCE.LotNumber, SOURCE.BranchCode, SOURCE.ShortItemNumber, 1);

                SELECT @v_NewNumWO = COUNT(*) FROM #Temp_WO;
                SET @v_NumRuns = @v_NumRuns + 1;

                IF(@v_NumWO = @v_NewNumWO OR @v_NumRuns = @c_MAX_RUNS) BEGIN
                    BREAK;
                END
            END;

            SELECT @v_NumRuns AS IterationsCompleted, @v_NewNumWO AS TotalWorkOrders;
            """;

        var result = await connection.QuerySingleAsync<(int IterationsCompleted, int TotalWorkOrders)>(
            traversalSql,
            new { p_MaxIterations = maxIterations },
            commandTimeout: 600);

        _logger.LogDebug(
            "Downstream traversal completed in {Iterations} iterations, found {TotalWorkOrders} total work orders",
            result.IterationsCompleted,
            result.TotalWorkOrders);
    }
}