using System;
using System.IO;
using System.Collections.Generic;
using System.Linq;
using ClosedXML.Excel;
using AsbCloudApp.Data;
using AsbCloudDb.Model;

namespace AsbCloudInfrastructure.Services
{
    public class WellOperationImportService
    {
        private const string sheetNamePlan = "План";
        private const string sheetNameFact = "Факт";

        private static readonly DateTime dateLimitMin = new DateTime(2001,1,1,0,0,0);
        private static readonly DateTime dateLimitMax = new DateTime(2099,1,1,0,0,0);
        private static readonly TimeSpan drillingDurationLimitMax = TimeSpan.FromDays(366);

        private readonly IAsbCloudDbContext db;

        private List<WellOperationCategory> categories = null;
        public List<WellOperationCategory> Categories { 
            get {
                if (categories is null)
                    categories = db.WellOperationCategories.ToList();
                return categories;
            }
        }

        private List<WellSectionType> sections = null;
        public List<WellSectionType> Sections
        {
            get
            {
                if (sections is null)
                    sections = db.WellSectionTypes.ToList();
                return sections;
            }
        }

        public WellOperationImportService(IAsbCloudDbContext db)
        {
            this.db = db;
        }

        public IEnumerable<WellOperationDto> ParseFile(string excelFilePath)
        {
            if (!File.Exists(excelFilePath))
                throw new FileNotFoundException($"Файл {excelFilePath} не найден.");

            return ParseWorkbook(excelFilePath);
        }

        private IEnumerable<WellOperationDto> ParseWorkbook(string excelFilePath)
        {
            using var sourceExcelWorkbook = new XLWorkbook(excelFilePath, XLEventTracking.Disabled);
            var sheetPlan = sourceExcelWorkbook.Worksheets.FirstOrDefault(ws => ws.Name == sheetNamePlan);
            if (sheetPlan is null)
                throw new FileFormatException($"Файл {excelFilePath} не не содержит листа {sheetNamePlan}.");

            var sheetFact = sourceExcelWorkbook.Worksheets.FirstOrDefault(ws => ws.Name == sheetNameFact);
            if (sheetFact is null)
                throw new FileFormatException($"Файл {excelFilePath} не не содержит листа {sheetNameFact}.");

            //sheetPlan.RangeUsed().RangeAddress.LastAddress.ColumnNumber
            var wellOperations = new List<WellOperationDto>();

            var wellOperationsPlan = ParseSheet(sheetPlan, 0);
            wellOperations.AddRange(wellOperationsPlan);

            var wellOperationsFact = ParseSheet(sheetFact, 1);
            wellOperations.AddRange(wellOperationsFact);

            return wellOperations;
        }

        private IEnumerable<WellOperationDto> ParseSheet(IXLWorksheet sheet, int idType)
        {
            const int headerRowsCount = 1;

            if (sheet.RangeUsed().RangeAddress.LastAddress.ColumnNumber < 7)
                throw new FileFormatException($"Лист {sheet.Name} содержит меньшее количество столбцев.");

            var count = sheet.RowsUsed().Count() - headerRowsCount;
            
            if (count > 1024)
                throw new FileFormatException($"Лист {sheet.Name} содержит слишком большое количество операций.");

            if (count <= 0)
                return new List<WellOperationDto>();

            var operations = new List<WellOperationDto>(count);
            var parseErrors = new List<string>();
            DateTime lastOperationDateStart = new DateTime();
            for (int i = 0; i < count; i++)
            {
                var row = sheet.Row(1 + i + headerRowsCount);
                try
                {
                    var operation = ParseRow(row, idType);
                    operations.Add(operation);
                                        
                    if (lastOperationDateStart > operation.DateStart)
                        parseErrors.Add($"Лист {sheet.Name} строка {row.RowNumber()} дата позднее даты предыдущей операции.");

                    lastOperationDateStart = operation.DateStart;
                }
                catch(FileFormatException ex)
                {
                    parseErrors.Add(ex.Message);
                }                
            };

            // проверка диапазона дат
            if(operations.Min(o => o.DateStart) - operations.Max(o => o.DateStart) > drillingDurationLimitMax)
                parseErrors.Add($"Лист {sheet.Name} содержит диапазон дат больше {drillingDurationLimitMax}");

            if (parseErrors.Any())
                throw new FileFormatException(string.Join("\r\n", parseErrors));

            return operations;
        }

        private WellOperationDto ParseRow(IXLRow row, int idType)
        {
            const int columnSection = 1;
            const int columnCategory = 2;
            const int columnCategoryInfo = 3;
            const int columnDepthStart = 4;
            const int columnDepthEnd = 5;
            const int columnDate = 6;
            const int columnDuration = 7;
            const int columnComment = 8;

            var vSection = row.Cell(columnSection).Value;
            var vCategory = row.Cell(columnCategory).Value;
            var vCategoryInfo = row.Cell(columnCategoryInfo).Value;
            var vDepthStart = row.Cell(columnDepthStart).Value;
            var vDepthEnd = row.Cell(columnDepthEnd).Value;
            var vDate = row.Cell(columnDate).Value;
            var vDuration = row.Cell(columnDuration).Value;
            var vComment = row.Cell(columnComment).Value;

            var operation =  new WellOperationDto{IdType = idType};

            if (vSection is string sectionName)
            {
                var section = Sections.Find(c => c.Caption.ToLower() == sectionName.ToLower());
                if (section is null)
                    throw new FileFormatException($"Лист {row.Worksheet.Name}. Строка {row.RowNumber()} указана некорректная секция");
                
                operation.IdWellSectionType = section.Id;
                operation.WellSectionTypeName = section.Caption;
            }
            else
                throw new FileFormatException($"Лист {row.Worksheet.Name}. Строка {row.RowNumber()} не указана секция");

            if (vCategory is string categoryName)
            {
                var category = Categories.Find(c => c.Name.ToLower() == categoryName.ToLower());
                if(category is null)
                    throw new FileFormatException($"Лист {row.Worksheet.Name}. Строка {row.RowNumber()} указана некорректная операция");

                operation.IdCategory = category.Id;
                operation.CategoryName = category.Name;
            }
            else
                throw new FileFormatException($"Лист {row.Worksheet.Name}. Строка {row.RowNumber()} не указана операция");

            if (vCategoryInfo is not null)
                operation.CategoryInfo = vCategoryInfo.ToString();

            if (vDepthStart is double depthStart && depthStart >= 0d && depthStart <= 20_000d)
                operation.DepthStart = depthStart;
            else
                throw new FileFormatException($"Лист {row.Worksheet.Name}. Строка {row.RowNumber()} не указана глубина на начало операции");

            if (vDepthEnd is double depthEnd && depthEnd >= 0d && depthEnd <= 20_000d)
                operation.DepthEnd = depthEnd;
            else
                throw new FileFormatException($"Лист {row.Worksheet.Name}. Строка {row.RowNumber()} не указана глубина при завершении операции");

            if (vDate is DateTime date && date > dateLimitMin && date < dateLimitMax)
                operation.DateStart = date;
            else
                throw new FileFormatException($"Лист {row.Worksheet.Name}. Строка {row.RowNumber()} неправильно указана дата/время начала операции");

            if (vDuration is double duration && duration >= 0d && duration <= 240d)
                operation.DurationHours = duration;
            else
                throw new FileFormatException($"Лист {row.Worksheet.Name}. Строка {row.RowNumber()} не указана длительность операции");

            if (vComment is not null)
                operation.Comment = vComment.ToString();

            return operation;
        }
    }
}