using FastEndpoints;
using FrameworkBLL.WorkFlow;
using GB5Shared.DTO.Framework.Login;
using GB5Shared.DTO.Framework.ResponseStandard;
using GB5Shared.DTO.WorkFlow;
using GB5Shared.FastEndPoint;
using GB5Shared.WorkFlow.WorkFlowEngine;
using static FrameworkDAL.Constant.Constant;
using static GB5Shared.DTO.WorkFlow.ContractsDTO;

namespace FrameworkSL.Endpoints.WorkFlow
{
    /// <summary>
    /// POST /WorkFlow/StartWorkflow
    ///
    /// Starts a new workflow instance for a document that has been saved.
    ///
    /// The caller should:
    ///  1. Save the document (e.g. Task) in its own transaction.
    ///  2. Build a <see cref="WorkflowStartRequest"/> from the saved DTO.
    ///  3. Call this endpoint to initiate the approval chain.
    ///
    /// Request body — <see cref="WorkflowStartRequest"/>:
    ///   EntityId              — MENTITY.ENTITYID of the document
    ///   OUId                  — Current session OU (LoginDTO.WorkOUId if omitted)
    ///   BizTransactionClassId — MBIZTRANSACTIONCLASS.BIZTRANSACTIONCLASSID (-1 = any)
    ///   BizTransactionId      — MBIZTRANSACTION.BIZTRANSACTIONID (-1 = any)
    ///   ObjectId              — PK of the saved record (e.g. TaskId)
    ///   DataJson              — Snapshot of the saved document (for audit trail)
    ///   Comment               — Optional submitter comment
    ///   Facts                 — Key/value pairs from the DTO evaluated against workflow
    ///                           conditions (e.g. { "TaskDetailType": 2 })
    ///
    /// Response:
    ///   200 — workflow started (or no workflow configured — saves normally)
    ///   400 — validation / configuration error with a descriptive message
    /// </summary>
    public class StartWorkflow
        : BaseEndpoint<StartWorkflow.StartWorkflowParameters, ResponseStandardDTO<object>>
    {
        private readonly IWorkFlowBLL _bll;

        public StartWorkflow(IWorkFlowBLL bll) => _bll = bll;

        public override void Configure()
        {
            Post("/WorkFlow/StartWorkflow");
            AllowAnonymous();
        }

        public record StartWorkflowParameters(
            [property: FromHeader] string Login,
            [property: FromBody]   WorkflowStartRequest Request
        );

        protected override string? GetCacheKey(
            StartWorkflowParameters req, LoginDTO login) => null;

        protected override async Task<ResponseStandardDTO<object>> ExecuteAsync(
            StartWorkflowParameters req,
            LoginDTO login,
            CancellationToken ct)
        {
            try
            {
                // Default OUId from session if caller omits it
                if (req.Request.OUId == 0)
                    req.Request.OUId = login.WorkOUId;

                var result = await _bll.StartWorkflow(req.Request, login);

                string message = result.IsStarted
                    ? "Workflow started successfully."
                    : "No workflow configured for this document — saved normally.";

                return await GB5Shared.ResponseStandard.Response
                    .CreateSuccessResponse(message, CacheKeyLevel.NotRequired, login);
            }
            catch (WorkflowEngineException ex)
            {
                // Business-rule / configuration errors — return 400 with exact message
                return await GB5Shared.ResponseStandard.Response
                    .CreateExceptionError<string>(ex, CacheKeyLevel.NotRequired,
                        login, ex.Message, 400);
            }
            catch (Exception ex)
            {
                return await GB5Shared.ResponseStandard.Response
                    .CreateExceptionError<string>(ex, CacheKeyLevel.NotRequired,
                        login, ex.Message, 500);
            }
        }
    }
}