using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Dapper;
using GB5Shared.DTO.Framework.Login;
using GB5Shared.QueryExecutor;
using RecruitmentDAL.DTO.Reports;

namespace RecruitmentDAL.Reports
{
    public class RecruiterWorkloadReportDAL : IRecruiterWorkloadReportDAL
    {
        private readonly IQueryExecutor _queryExecutor;

        public RecruiterWorkloadReportDAL(IQueryExecutor queryExecutor)
        {
            _queryExecutor = queryExecutor;
        }

        public async Task<PagedResult<RecruiterWorkloadDTO>> GetRecruiterWorkload(
            int firstNumber, int maxResult, RecruitmentReportCriteria criteria, LoginDTO login, CancellationToken ct)
        {
            var (filter, closedDateFilter, parameters) = BuildFilter(criteria, login);
            parameters.Add("Offset", Math.Max(0, firstNumber - 1));
            parameters.Add("PageSize", maxResult > 0 ? maxResult : 500);

            var sql = RecruiterWorkloadReportQB.GET_RECRUITER_WORKLOAD
                .Replace("{AssignedRecruiterFilter}", filter)
                .Replace("{ClosedDateFilter}", closedDateFilter);

            return await _queryExecutor
                .QueryPagedAsync<RecruiterWorkloadDTO>(login, sql, parameters)
                .ConfigureAwait(false);
        }

        public async IAsyncEnumerable<RecruiterWorkloadDTO> GetRecruiterWorkloadStream(
            int firstNumber, int maxResult, RecruitmentReportCriteria criteria, LoginDTO login,
            [EnumeratorCancellation] CancellationToken ct)
        {
            var (filter, closedDateFilter, parameters) = BuildFilter(criteria, login);
            var sql = RecruiterWorkloadReportQB.GET_RECRUITER_WORKLOAD
                .Replace("{AssignedRecruiterFilter}", filter)
                .Replace("{ClosedDateFilter}", closedDateFilter);

            await foreach (var row in _queryExecutor
                .QueryStreamAsync<RecruiterWorkloadDTO>(login, sql, parameters, ct)
                .ConfigureAwait(false))
            {
                yield return row;
            }
        }

        private static (string Filter, string ClosedDateFilter, DynamicParameters Parameters) BuildFilter(
            RecruitmentReportCriteria criteria, LoginDTO login)
        {
            var filter = new StringBuilder();
            var closedDateFilter = new StringBuilder();
            var p = new DynamicParameters();
            p.Add("TenantId", login.ClientId);

            RecruitmentReportFilterBuilder.AppendAssignedRecruiter(filter, p, criteria, "JR.ASSIGNEDRECRUITERID");
            RecruitmentReportFilterBuilder.AppendDateRange(closedDateFilter, p, criteria, "JR.MODIFIEDON");

            return (filter.ToString(), closedDateFilter.ToString(), p);
        }
    }
}