using System.Text;

using MesaFabApproval.Shared.Models;

using Microsoft.Extensions.Caching.Memory;

namespace MesaFabApproval.API.Services;

public interface IPCRBService {
    public Task CreateNewPCRB(PCRB pcrb);
    public Task<IEnumerable<PCRB>> GetAllPCRBs(bool bypassCache);
    public Task<PCRB> GetPCRBByPlanNumber(int planNumber, bool bypassCache);
    public Task<PCRB> GetPCRBByTitle(string title, bool bypassCache);
    public Task UpdatePCRB(PCRB pcrb);
    public Task DeletePCRB(int planNumber);
}

public class PCRBService : IPCRBService {
    private readonly ILogger<PCRBService> _logger;
    private readonly IDalService _dalService;
    private readonly IMemoryCache _cache;
    private readonly IUserService _userService;
    

    public PCRBService(ILogger<PCRBService> logger,
                       IDalService dalService,
                       IMemoryCache cache,
                       IUserService userService) {
        _logger = logger ?? throw new ArgumentNullException("ILogger not injected");
        _dalService = dalService ?? throw new ArgumentNullException("IDalService not injected");
        _cache = cache ?? throw new ArgumentNullException("IMemoryCache not injected");
        _userService = userService ?? throw new ArgumentNullException("IUserService not injected");
    }

    public async Task CreateNewPCRB(PCRB pcrb) {
        try {
            _logger.LogInformation("Attempting to create new PCRB");

            if (pcrb is null) throw new ArgumentNullException("PCRB cannot be null");

            StringBuilder queryBuilder = new();
            queryBuilder.Append("insert into CCChangeControl (OwnerID, Title, ChangeLevel, ReasonForChange, ");
            queryBuilder.Append("ChangeDescription, IsITAR, CurrentStep, InsertTimeStamp, LastUpdateDate) ");
            queryBuilder.Append($"values ({pcrb.OwnerID}, '{pcrb.Title}', '{pcrb.ChangeLevel}', ");
            queryBuilder.Append($"'{pcrb.ReasonForChange}', '{pcrb.ChangeDescription}', ");
            queryBuilder.Append($"{Convert.ToInt32(pcrb.IsITAR)}, {pcrb.CurrentStep}, ");
            queryBuilder.Append($"'{pcrb.InsertTimeStamp.ToString("yyyy-MM-dd HH:mm:ss")}', ");
            queryBuilder.Append($"'{DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss")}')");

            int rowsCreated = await _dalService.ExecuteAsync(queryBuilder.ToString());

            if (rowsCreated <= 0) throw new Exception("unable to insert new PCRB in the database");
        } catch (Exception ex) {
            _logger.LogError($"Unable to create new PCRB, because {ex.Message}");
            throw;
        }
    }

    public async Task<IEnumerable<PCRB>> GetAllPCRBs(bool bypassCache) {
        try {
            _logger.LogInformation("Attempting to get all PCRBs");

            IEnumerable<PCRB>? allPCRBs = null;
            if (!bypassCache) allPCRBs = _cache.Get<IEnumerable<PCRB>>("allPCRBs");

            if (allPCRBs is null) {
                string sql = "select * from CCChangeControl";

                allPCRBs = (await _dalService.QueryAsync<PCRB>(sql)).ToList();

                foreach (PCRB pcrb in allPCRBs) {
                    if (string.IsNullOrWhiteSpace(pcrb.OwnerName) && pcrb.OwnerID > 0)
                        pcrb.OwnerName = (await _userService.GetUserByUserId(pcrb.OwnerID)).GetFullName();
                }

                _cache.Set("allPCRBs", allPCRBs, DateTimeOffset.Now.AddHours(1));
            }

            if (allPCRBs is null || allPCRBs.Count() == 0)
                throw new Exception("no PCRBs found");

            return allPCRBs;
        } catch (Exception ex) {
            _logger.LogError($"Unable to get all PCRBs, because {ex.Message}");
            throw;
        }
    }

    public async Task<PCRB> GetPCRBByPlanNumber(int planNumber, bool bypassCache) {
        try {
            _logger.LogInformation("Attempting to get a PCRB by plan#");

            if (planNumber <= 0) throw new ArgumentException($"{planNumber} is not a valid PCRB#");

            PCRB? pcrb = null;

            if (!bypassCache) pcrb = _cache.Get<PCRB>($"pcrb{planNumber}");

            if (pcrb is null) {
                string sql = $"select * from CCChangeControl where PlanNumber={planNumber}";

                pcrb = (await _dalService.QueryAsync<PCRB>(sql)).FirstOrDefault();

                if (pcrb is not null) {
                    if (string.IsNullOrWhiteSpace(pcrb.OwnerName) && pcrb.OwnerID > 0)
                        pcrb.OwnerName = (await _userService.GetUserByUserId(pcrb.OwnerID)).GetFullName();

                    _cache.Set($"pcrb{planNumber}", pcrb, DateTimeOffset.Now.AddHours(1));
                    _cache.Set($"pcrb{pcrb.Title}", pcrb, DateTimeOffset.Now.AddHours(1));
                }
            }

            if (pcrb is null) throw new Exception($"unable to find PCRB {planNumber}");

            return pcrb;
        } catch (Exception ex) {
            _logger.LogError($"Unable to get PCRB by Plan #, because {ex.Message}");
            throw;
        }
    }

    public async Task<PCRB> GetPCRBByTitle(string title, bool bypassCache) {
        try {
            _logger.LogInformation("Attempting to get a PCRB by title");

            if (string.IsNullOrWhiteSpace(title)) throw new ArgumentException("Title cannot be null or empty");

            PCRB? pcrb = null;

            if (!bypassCache) pcrb = _cache.Get<PCRB>($"pcrb{title}");

            if (pcrb is null) {
                string sql = $"select * from CCChangeControl where Title='{title}'";

                pcrb = (await _dalService.QueryAsync<PCRB>(sql)).FirstOrDefault();

                if (pcrb is not null) {
                    if (string.IsNullOrWhiteSpace(pcrb.OwnerName) && pcrb.OwnerID > 0)
                        pcrb.OwnerName = (await _userService.GetUserByUserId(pcrb.OwnerID)).GetFullName();

                    _cache.Set($"pcrb{title}", pcrb, DateTimeOffset.Now.AddHours(1));
                    _cache.Set($"pcrb{pcrb.PlanNumber}", pcrb, DateTimeOffset.Now.AddHours(1));
                }
            }

            if (pcrb is null) throw new Exception($"unable to find PCRB {title}");

            return pcrb;
        } catch (Exception ex) {
            _logger.LogError($"Unable to get PCRB by title, because {ex.Message}");
            throw;
        }
    }

    public async Task UpdatePCRB(PCRB pcrb) {
        try {
            _logger.LogInformation($"Attempting to update PCRB");

            if (pcrb is null) throw new ArgumentNullException("PCRB cannot be null");

            StringBuilder queryBuilder = new();
            queryBuilder.Append($"update CCChangeControl set OwnerID={pcrb.OwnerID}, ");
            queryBuilder.Append($"Title='{pcrb.Title}', ChangeLevel='{pcrb.ChangeLevel}', ");
            queryBuilder.Append($"CurrentStep={pcrb.CurrentStep}, ReasonForChange='{pcrb.ReasonForChange}', ");
            queryBuilder.Append($"ChangeDescription='{pcrb.ChangeDescription}', ");
            queryBuilder.Append($"IsITAR={Convert.ToInt32(pcrb.IsITAR)}, ");
            queryBuilder.Append($"InsertTimeStamp='{pcrb.InsertTimeStamp.ToString("yyyy-MM-dd HH:mm:ss")}', ");
            queryBuilder.Append($"LastUpdateDate='{DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss")}' ");
            queryBuilder.Append($"where PlanNumber={pcrb.PlanNumber}");

            int rowsAffected = await _dalService.ExecuteAsync(queryBuilder.ToString());

            if (rowsAffected <= 0) throw new Exception("unable to perform update in database");

            _cache.Set($"pcrb{pcrb.Title}", pcrb, DateTimeOffset.Now.AddHours(1));
            _cache.Set($"pcrb{pcrb.PlanNumber}", pcrb, DateTimeOffset.Now.AddHours(1));

            IEnumerable<PCRB>? allPCRBs = _cache.Get<IEnumerable<PCRB>>("allPCRBs");
            if (allPCRBs is not null) {
                List<PCRB> pcrbList = allPCRBs.ToList();
                pcrbList.RemoveAll(p => p.PlanNumber == pcrb.PlanNumber);
                pcrbList.Add(pcrb);
                _cache.Set("allPCRBs", pcrbList, DateTimeOffset.Now.AddHours(1));
            }
        } catch (Exception ex) {
            _logger.LogError($"Unable to update PCRB, because {ex.Message}");
            throw;
        }
    }

    public async Task DeletePCRB(int planNumber) {
        try {
            _logger.LogInformation($"Attempting to delete PCRB {planNumber}");

            if (planNumber <= 0) throw new ArgumentException($"{planNumber} is not a valid PCRB Plan #");

            string sql = $"delete from CCChangeControl where PlanNumber={planNumber}";

            int rowsAffected = await _dalService.ExecuteAsync(sql);

            if (rowsAffected <= 0) throw new Exception("delete operation failed in database");

            IEnumerable<PCRB>? allPCRBs = _cache.Get<IEnumerable<PCRB>>("allPCRBs");
            if (allPCRBs is not null) {
                List<PCRB> pcrbList = allPCRBs.ToList();
                pcrbList.RemoveAll(p => p.PlanNumber == planNumber);
                _cache.Set("allPCRBs", pcrbList, DateTimeOffset.Now.AddHours(1));
            }
        } catch (Exception ex) {
            _logger.LogError($"Unable to delete PCRB {planNumber}, because {ex.Message}");
            throw;
        }
    }
}