using Diligent.WebAPI.Contracts.DTOs.Pattern;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Diligent.WebAPI.Business.Services
{
    public class PatternService : IPatternService
    {
        private readonly DatabaseContext _context;
        private readonly IMapper _mapper;
        private readonly ISelectionLevelService _selectionLevelService;
        private readonly ILogger<PatternService> _logger;

        public PatternService(DatabaseContext context, IMapper mapper, ISelectionLevelService selectionLevelService, ILogger<PatternService> logger)
        {
            _context = context;
            _mapper = mapper;
            _selectionLevelService = selectionLevelService;
            _logger = logger;
        }

        public async Task<List<PatternResponseDto>> GetAllAsync()
        {
            _logger.LogInformation("Start getting all Patterns");
            _logger.LogInformation("Getting data from DB");
            var fromDb = await _context.Patterns.Include(x => x.SelectionLevel).ToListAsync();
            _logger.LogInformation($"Received {fromDb.Count} patterns from db.");
            _logger.LogInformation($"Mapping received patterns to PatternResponseDto");
            var result = _mapper.Map<List<PatternResponseDto>>(fromDb);
            _logger.LogInformation($"Patterns has been mapped and received to client: {result.Count} mapped patterns");
            return result;
        }

        public async Task<PatternResponseDto> GetByIdAsync(int id)
        {
            _logger.LogInformation($"Start searching Pattern with id = {id}");
            var pattern = await _context.Patterns.Include(x => x.SelectionLevel).Where(x => x.Id == id).FirstOrDefaultAsync();

            if (pattern is null)
            {
                _logger.LogError($"Pattern with id = {id} not found");
                throw new EntityNotFoundException("Pattern not found");
            }

            _logger.LogInformation($"Mapping Pattern with id = {id}");
            PatternResponseDto result = _mapper.Map<PatternResponseDto>(pattern);
            _logger.LogInformation($"Pattern with id = {id} mapped successfully");
            return result;
        }

        public async Task<List<PatternResponseDto>> GetFilteredPatternsAsync(FilterPatternDto filterPatternDto)
        {
            _logger.LogInformation($"Start getting all filtered Patterns");
            _logger.LogInformation("Getting data from DB");
            var filteredPatterns = await _context.Patterns.Include(x => x.SelectionLevel).ToListAsync();
            _logger.LogInformation($"Received {filteredPatterns.Count} patterns from db.");

            _logger.LogInformation($"Mapping received patterns to PatternResponseDto");
            List<PatternResponseDto> result = _mapper.Map<List<PatternResponseDto>>(filteredPatterns.FilterApplicants(filterPatternDto));
            _logger.LogInformation($"Patterns has been mapped and received to client: {result.Count} mapped patterns");
            return result;
        }

        public async Task CreateAsync(PatternCreateDto patternCreateDto)
        {
            _logger.LogInformation($"Start creating Pattern");
            _logger.LogInformation($"Check is Pattern in database");
            var patternExists = await _context.Patterns.Include(x => x.SelectionLevel).Where(x => x.Title == patternCreateDto.Title && x.SelectionLevelId == patternCreateDto.SelectionLevelId).FirstOrDefaultAsync();

            if (patternExists is not null)
            {
                _logger.LogError($"Pattern already exists in database");
                throw new EntityNotFoundException("Pattern already exists in database");
            }

            _logger.LogInformation($"Pattern is not in database");
            _logger.LogInformation($"Mapping PatternCreateDto to model");
            var pattern = _mapper.Map<Pattern>(patternCreateDto);
            _logger.LogInformation($"Pattern mapped successfully");


            _logger.LogInformation($"Start searching SelectionLevel with id = {patternCreateDto.SelectionLevelId}");
            var selectionLevel = await _selectionLevelService.GetByIdEntity(patternCreateDto.SelectionLevelId);

            if(selectionLevel == null)
            {
                _logger.LogError($"SelectionLevel with id = {patternCreateDto.SelectionLevelId} not found");
                throw new EntityNotFoundException("Selection level not found");
            }

            _logger.LogInformation($"Add founded SelectionLevel to pattern");
            pattern.SelectionLevel = selectionLevel;

            await _context.AddAsync(pattern);
            _logger.LogInformation($"Saving Ad to db...");
            
            var result = _context.SaveChangesAsync();
            _logger.LogInformation($"Saved Ad to db...");

            await result;
        }

        public async Task UpdateAsync(PatternUpdateDto patternUpdateDto, int id)
        {
            _logger.LogInformation($"Start updating Pattern");
            _logger.LogInformation($"Check is Pattern in database");
            var patternExists = await _context.Patterns.Include(x => x.SelectionLevel).Where(x => x.Title == patternUpdateDto.Title && x.SelectionLevelId == patternUpdateDto.SelectionLevelId).FirstOrDefaultAsync();

            if (patternExists is not null)
            {
                _logger.LogError($"Pattern already exists in database");
                throw new EntityNotFoundException("Pattern already exists in database");
            }

            _logger.LogInformation($"Start searching Pattern with id = {id}");
            var pattern = await _context.Patterns.Where(x => x.Id == id).FirstOrDefaultAsync();

            if (pattern is null)
            {
                _logger.LogError($"Pattern with id = {id} not found");
                throw new EntityNotFoundException("Pattern not found");
            }

            _logger.LogInformation($"Mapping Pattern with id = {id}");
            _mapper.Map(patternUpdateDto, pattern);
            _logger.LogInformation($"Pattern with id = {id} mapped successfully");


            _logger.LogInformation($"Start searching SelectionLevel with id = {patternUpdateDto.SelectionLevelId}");
            var selectionLevel = await _selectionLevelService.GetByIdEntity(patternUpdateDto.SelectionLevelId);

            if (selectionLevel == null)
            {
                _logger.LogError($"SelectionLevel with id = {patternUpdateDto.SelectionLevelId} not found");
                throw new EntityNotFoundException("Selection level not found");
            }

            _logger.LogInformation($"Add founded SelectionLevel to pattern");
            pattern.SelectionLevel = selectionLevel;

            _context.Entry(pattern).State = EntityState.Modified;
            var result = _context.SaveChangesAsync();
            _logger.LogInformation($"Pattern saved to DB");
            await result;
        }

        public async Task DeleteAsync(int id)
        {
            _logger.LogInformation($"Start searching Pattern with id = {id}");
            var pattern = await _context.Patterns.FindAsync(id);

            if (pattern is null)
            {
                _logger.LogError($"Pattern with id = {id} not found");
                throw new EntityNotFoundException("Pattern not found");
            }

            _context.Patterns.Remove(pattern);
            var result = _context.SaveChangesAsync();
            _logger.LogInformation($"Ad saved to DB");
            await result;
        }
    }
}