using ECMJobRunner.Application.Common.Constants;
using ECMJobRunner.Application.Common.Dtos;
using ECMJobRunner.Application.Common.Exceptions;
using ECMJobRunner.Application.Common.Interfaces;
using ECMJobRunner.Application.Common.Options;
using ECMJobRunner.Application.DEXJob.Commands;
using MediatR;
using Microsoft.Extensions.Options;
using System;
using System.Text.RegularExpressions;
using System.Threading;
using System.Threading.Tasks;

namespace ECMJobRunner.Application.DEXJob.Commands.Behaviors
{
    /// <summary>
    /// Pipeline behavior that executes the check SQL query for DEX jobs
    /// Runs after MainQueryExecutionBehavior and validates query results
    /// </summary>
    /// <typeparam name="TRequest">The request type</typeparam>
    /// <typeparam name="TResponse">The response type</typeparam>
    public class CheckQueryExecutionBehavior<TRequest, TResponse> : IPipelineBehavior<TRequest, TResponse>
        where TRequest : notnull
    {
        private readonly ISQLExecutor _executor;
        private readonly DexJobOptions _options;

        /// <summary>
        /// Initializes a new instance of CheckQueryExecutionBehavior
        /// </summary>
        /// <param name="executor">SQL executor for query execution</param>
        /// <param name="options">DEX job configuration options</param>
        public CheckQueryExecutionBehavior(ISQLExecutor executor, IOptions<DexJobOptions> options)
        {
            _executor = executor;
            _options = options.Value;
        }

        /// <summary>
        /// Handles the pipeline behavior
        /// Executes check query if request is TriggeringDEXJobCommand
        /// </summary>
#if NET48
        public async Task<TResponse> Handle(TRequest request, CancellationToken cancellationToken, RequestHandlerDelegate<TResponse> next)
#else
        public async Task<TResponse> Handle(TRequest request, RequestHandlerDelegate<TResponse> next, CancellationToken cancellationToken)
#endif
        {
            if (request is TriggeringDEXJobCommand command)
            {
                await ExecuteCheckQueryAsync(command, cancellationToken);
            }

            return await next();
        }

        private async Task ExecuteCheckQueryAsync(TriggeringDEXJobCommand command, CancellationToken cancel)
        {
            if (!string.IsNullOrWhiteSpace(command.Job.SqlCheckQuery))
            {
                var sqlCheckQuery = Regex.Replace(
                    command.Job.SqlCheckQuery!,
                    _options.Placeholders.BatchId.Pattern,
                    command.BatchId,
                    _options.Placeholders.BatchId.RegexOptions);

                try
                {
                    var result = await _executor.ExecuteQueryAsync<CheckQueryResult>(sqlCheckQuery, cancel);
                    if (_options.Error.CheckQuery.OnUnexpectedResult == ErrorAction.Stop)
                    {
                        if (result is null)
                            throw new JobSqlException(
                                jobName: "Triggering DEX",
                                processName: "Check Query",
                                batchId: command.BatchId,
                                reason: "Check Query returned nothing.",
                                query: sqlCheckQuery,
                                innerException: null);
                        else if (result.ReturnValue <= 0)
                            throw new JobSqlException(
                                jobName: "Triggering DEX",
                                processName: "Check Query",
                                batchId: command.BatchId,
                                reason: $"The query unexpectedly returned the value {result.ReturnValue}. The expected value was any value greater than 0.",
                                query: sqlCheckQuery,
                                innerException: null);
                    }
                }
                catch (Exception ex)
                {
                    if (_options.Error.CheckQuery.OnExecution == ErrorAction.Stop)
                        throw new JobSqlException(
                            jobName: "Triggering DEX",
                            processName: "Check Query",
                            batchId: command.BatchId,
                            reason: null,
                            query: sqlCheckQuery,
                            innerException: ex
                        );
                }
            }
            else if (_options.Error.CheckQuery.IfNullOrWhiteSpace == ErrorAction.Stop)
            {
                throw new JobSqlException(
                    jobName:"Triggering DEX", 
                    processName:"Check Query", 
                    batchId:command.BatchId, 
                    reason: "SQL Check Query is null or empty",
                    query: null,
                    innerException: null
                );
            }
        }
    }
}