using AsbCloudApp.Data;
using AsbCloudApp.Exceptions;
using AsbCloudApp.Services;
using AsbCloudDb.Model;
using Mapster;
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

namespace AsbCloudInfrastructure.Services.DrillingProgram
{
    public class DrillingProgramService : IDrillingProgramService
    {
        private readonly IAsbCloudDbContext context;
        private readonly IFileService fileService;
        private readonly IUserService userService;

        private const int idFileCategoryDrillingProgram = 1000;
        private const int idFileCategoryDrillingProgramPartsStart = 1001;
        private const int idFileCategoryDrillingProgramPartsEnd = 1100;

        private const int idPartStateNoFile = 0;
        private const int idPartStateApproving = 1;
        private const int idPartStateApproved = 2;

        private const int idMarkTypeReject = 0;
        private const int idMarkTypeApprove = 1;

        private const int idUserRolePublisher = 1;
        private const int idUserRoleApprover = 2;

        private const int idStateNotInitialized = 0;
        private const int idStateApproving = 1;
        private const int idStateCreating = 2;
        private const int idStateReady = 3;

        public DrillingProgramService(IAsbCloudDbContext context, IFileService fileService, IUserService userService)
        {
            this.context = context;
            this.fileService = fileService;
            this.userService = userService;
        }

        public async Task<IEnumerable<FileCategoryDto>> GetCategoriesAsync(CancellationToken token = default)
        {
            var result = await context.FileCategories
                .Where(c=>c.Id > idFileCategoryDrillingProgramPartsStart && c.Id < idFileCategoryDrillingProgramPartsEnd)
                .ToListAsync(token);
            return result.Select(c => c.Adapt<FileCategoryDto>());
        }

        public async Task<DrillingProgramStateDto> GetStateAsync(int idWell, int idUser, CancellationToken token = default)
        {
            // Задание от геологов
            // Профиль ствола скважины(ННБ)
            // Технологические расчеты(ННБ)
            // Долотная программа
            // Программа по растворам
            // Программа геофизических исследований
            // Планы спусков обсадных колонн
            // Программы цементирования обсадных колонн

            var fileCategories = await context.FileCategories
                .Where(c => c.Id >= idFileCategoryDrillingProgramPartsStart &&
                    c.Id < idFileCategoryDrillingProgramPartsEnd)
                .ToListAsync(token);

            var files = await context.Files
                .Include(f => f.FileMarks)
                .ThenInclude(m => m.User)
                .Include(f => f.Author)
                .Include(f => f.FileCategory)
                .Where(f => f.IdWell == idWell && 
                    f.IdCategory >= idFileCategoryDrillingProgram && 
                    f.IdCategory < idFileCategoryDrillingProgramPartsEnd &&
                    f.IsDeleted == false)
                .OrderBy(f => f.UploadDate)
                .ToListAsync(token);

            var partEntities = await context.DrillingProgramParts
                .Include(p => p.RelatedUsers)
                .ThenInclude(r => r.User)
                .Where(p => p.IdWell == idWell)
                .ToListAsync(token);

            var parts = new List<DrillingProgramPartDto>(partEntities.Count);
            
            foreach (var partEntity in partEntities)
            {
                var part = ConvertPart(idUser, fileCategories, files, partEntity);
                parts.Add(part);
            }

            var state = new DrillingProgramStateDto();
            state.Parts = parts;
            state.Program = files.FirstOrDefault(f => f.IdCategory == idFileCategoryDrillingProgram)
                .Adapt<FileInfoDto>();

            if (parts.Any())
            {
                if(parts.All(p=>p.IdState == idPartStateApproved))
                {
                    if (state.Program is not null)
                        state.IdState = idStateReady;
                    else
                        state.IdState = idStateCreating;
                }
                else
                    state.IdState = idStateApproving;
            }
            else
                state.IdState = idStateNotInitialized;

            return state;
        }

        public async Task<int> AddFile(int idPart, int idUser, string fileFullName, System.IO.Stream fileStream, CancellationToken token = default)
        {
            var part = await context.DrillingProgramParts
                .Include(p => p.RelatedUsers)
                .FirstOrDefaultAsync(p => p.Id == idPart);
            
            if (part == null)
                throw new ArgumentInvalidException($"DrillingProgramPart id == {idPart} does not exist", nameof(idPart));

            if (! part.RelatedUsers.Any(r => r.IdUser == idUser && r.IdUserRole == idUserRolePublisher))
                throw new ForbidException($"User {idUser} is not in the publisher list.");

            var result = await fileService.SaveAsync(
                part.IdWell, 
                idUser, 
                part.IdFileCategory, 
                fileFullName, 
                fileStream, 
                token);

            await RemoveDrillingProgramAsync(part.IdWell, token);
            return result.Id;
        }
    
        public async Task<int> AddPartAsync(int idWell, int idFileCategory, CancellationToken token = default)
        {
            var part = new DrillingProgramPart
            {
                IdWell = idWell,
                IdFileCategory = idFileCategory,
            };
            var entry = context.DrillingProgramParts.Add(part);
            await context.SaveChangesAsync(token);

            await RemoveDrillingProgramAsync(part.IdWell, token);
            return entry.Entity.Id;
        }

        public async Task<int> RemovePartAsync(int idWell, int idFileCategory, CancellationToken token = default)
        {
            var whereQuery = context.DrillingProgramParts
                .Where(r => r.IdWell == idWell &&
                    r.IdFileCategory == idFileCategory);

            context.DrillingProgramParts.RemoveRange(whereQuery);

            await RemoveDrillingProgramAsync(idWell, token);
            return await context.SaveChangesAsync(token);
        }

        public async Task<int> AddUserAsync(int idUser, int idPart, int idUserRole, CancellationToken token = default)
        {
            var user = await userService.GetAsync(idUser, token);
            if (user is null)
                throw new ArgumentInvalidException($"User id == {idUser} does not exist", nameof(idUser));

            var drillingProgramPart = await context.DrillingProgramParts.FirstOrDefaultAsync(p => p.Id == idPart, token);
            if (drillingProgramPart is null)
                throw new ArgumentInvalidException($"DrillingProgramPart id == {idPart} does not exist", nameof(idPart));

            if (idUserRole != idUserRoleApprover && idUserRole != idUserRolePublisher)
                throw new ArgumentInvalidException($"idUserRole ({idPart}), should be approver ({idUserRoleApprover}) or publisher({idUserRolePublisher})", nameof(idPart));

            var newRelation = new RelationUserDrillingProgramPart
            {
                IdUser = idUser,
                IdDrillingProgramPart = idPart,
                IdUserRole = idUserRole,
            };

            context.RelationDrillingProgramPartUsers.Add(newRelation);
            if(idUserRole == idUserRoleApprover)
                await RemoveDrillingProgramAsync(drillingProgramPart.IdWell, token);
            return await context.SaveChangesAsync(token);
        }

        public async Task<int> RemoveUserAsync(int idUser, int idPart, int idUserRole, CancellationToken token = default)
        {
            var whereQuery = context.RelationDrillingProgramPartUsers
                .Where(r => r.IdUser == idUser &&
                    r.IdDrillingProgramPart == idPart &&
                    r.IdUserRole == idUserRole);

            context.RelationDrillingProgramPartUsers.RemoveRange(whereQuery);
            if (idUserRole == idUserRoleApprover)
            {
                var part = await context.DrillingProgramParts.FirstOrDefaultAsync(p => p.Id == idPart, token);
                await CheckAndEnqueueMakeProgramAsync(part.IdWell, token);
            }
                
            return await context.SaveChangesAsync(token);
        }

        public async Task<int> AddOrReplaceFileMarkAsync(FileMarkDto fileMarkDto, int idUser, CancellationToken token)
        {
            if(fileMarkDto.IdMarkType != idMarkTypeApprove &&
                fileMarkDto.IdMarkType != idMarkTypeReject)
                throw new ArgumentInvalidException($"В этом методе допустимы только отметки о принятии или отклонении.", nameof(fileMarkDto));

            var fileInfo = await fileService.GetInfoAsync(fileMarkDto.IdFile, token)
                .ConfigureAwait(false);

            if (fileInfo is null)
                throw new ArgumentInvalidException($"Файла для такой отметки не существует.", nameof(fileMarkDto));

            if (fileInfo.IdCategory < idFileCategoryDrillingProgramPartsStart ||
                fileInfo.IdCategory > idFileCategoryDrillingProgramPartsEnd)
                throw new ArgumentInvalidException($"Этот метод допустим только для файлов-частей программы бурения.", nameof(fileMarkDto));

            var part = await context.DrillingProgramParts
                .FirstOrDefaultAsync(p => p.IdWell == fileInfo.IdWell && p.IdFileCategory == fileInfo.IdCategory, token);

            if (!part.RelatedUsers.Any(r => r.IdUser == idUser && r.IdUserRole == idUserRoleApprover))
                throw new ForbidException($"User {idUser} is not in the approvers list.");

            var oldMarksIds = fileInfo.FileMarks
                ?.Where(m => m.User.Id == idUser)
                .Select(m => m.Id);

            if(oldMarksIds?.Any() == true)
                await fileService.MarkFileMarkAsDeletedAsync(oldMarksIds, token);

            var result = await fileService.CreateFileMarkAsync(fileMarkDto, idUser, token)
                .ConfigureAwait(false);

            if(fileMarkDto.IdMarkType == idMarkTypeApprove)
                await CheckAndEnqueueMakeProgramAsync(fileInfo.IdWell, token);
            else
                await RemoveDrillingProgramAsync(fileInfo.IdWell, token);

            return result;
        }

        public async Task<int> MarkAsDeletedFileMarkAsync(int idMark,
            CancellationToken token)
        {
            var fileInfo = await fileService.GetByMarkId(idMark, token)
                .ConfigureAwait(false);

            if (fileInfo.IdCategory < idFileCategoryDrillingProgramPartsStart ||
                fileInfo.IdCategory > idFileCategoryDrillingProgramPartsEnd)
                throw new ArgumentInvalidException($"Этот метод допустим только для файлов-частей программы бурения.", nameof(idMark));

            var result = await fileService.MarkFileMarkAsDeletedAsync(idMark, token)
                .ConfigureAwait(false);

            await RemoveDrillingProgramAsync(fileInfo.IdWell, token);
            return result;
        }

        private static DrillingProgramPartDto ConvertPart(int idUser, List<FileCategory> fileCategories, List<FileInfo> files, DrillingProgramPart partEntity)
        {
            var part = new DrillingProgramPartDto
            {
                IdFileCategory = partEntity.IdFileCategory,
                Name = fileCategories.FirstOrDefault(c => c.Id == partEntity.IdFileCategory).Name,
                Approvers = partEntity.RelatedUsers
                                .Where(u => u.IdUserRole == idUserRoleApprover)
                                .Select(u => u.Adapt<UserDto>()),
                Publishers = partEntity.RelatedUsers
                                .Where(u => u.IdUserRole == idUserRolePublisher)
                                .Select(u => u.Adapt<UserDto>()),
                PermissionToApprove = partEntity.RelatedUsers
                                .Any(u => u.IdUserRole == idUserRoleApprover && u.IdUser == idUser),
                PermissionToUpload = partEntity.RelatedUsers
                                .Any(u => u.IdUserRole == idUserRolePublisher && u.IdUser == idUser),
            };

            var fileEntity = files.LastOrDefault(f => f.IdCategory == partEntity.IdFileCategory);

            if (fileEntity is not null)
            {
                part.File = fileEntity.Adapt<FileInfoDto>();
                var marks = fileEntity.FileMarks.Where(m => !m.IsDeleted);

                if (marks.Any())
                {
                    var hasReject = marks.Any(m => m.IdMarkType == idMarkTypeReject);
                    if (!hasReject)
                    {
                        var allAproved = part.Approvers.All(a => marks.Any(m => m.IdUser == a.Id && m.IdMarkType == idMarkTypeApprove));
                        if (allAproved)
                            part.IdState = idPartStateApproved;
                    }
                }
                else
                    part.IdState = idPartStateApproving;
            }
            else
                part.IdState = idPartStateNoFile;

            return part;
        }

        private async Task CheckAndEnqueueMakeProgramAsync(int idWell, CancellationToken token)
        {
            var state = await GetStateAsync(idWell, 0, token);
            if(state.IdState == idStateCreating)
            {
                // TODO: check if task is running else enqueue task
                throw new NotImplementedException();
            }
        }

        private async Task<int> RemoveDrillingProgramAsync(int idWell, CancellationToken token)
        {
            // TODO: dequeue task if it exist
            var filesIds = await context.Files
                .Where(f => f.IdWell == idWell &&
                    f.IdCategory == idFileCategoryDrillingProgram)
                .Select(f => f.Id)
                .ToListAsync(token);
            if (filesIds.Any())
                return await fileService.DeleteAsync(filesIds, token);
            else
                return 0;
        }

    }
}