using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Threading.Tasks;
using FarmmapsApi;
using FarmmapsApi.Models;
using FarmmapsApi.Services;
using FarmmapsKPI.Models;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using static FarmmapsApiSamples.Constants;

namespace FarmmapsKPI
{
    public class KPIApplication : IApplication
    {
        //private const string DownloadFolder = "Downloads";
        private const string SettingsFile = "settings.json";

        private readonly ILogger<KPIApplication> _logger;
        private readonly FarmmapsApiService _farmmapsApiService;
        private readonly KPIService _kpiService;
        private readonly GeneralService _generalService;

        private Settings _settings;

        public KPIApplication(ILogger<KPIApplication> logger, FarmmapsApiService farmmapsApiService,
            GeneralService generalService, KPIService kpiService)
        {
            _logger = logger;
            _farmmapsApiService = farmmapsApiService;
            _generalService = generalService;
            _kpiService = kpiService;
        }

        public async Task RunAsync()
        {
            var fieldsInputJson = File.ReadAllText("KPIInput.json");

            List<KPIInput> fieldsInputs = JsonConvert.DeserializeObject<List<KPIInput>>(fieldsInputJson);

            // !! this call is needed the first time an api is called with a fresh clientid and secret !!
            await _farmmapsApiService.GetCurrentUserCodeAsync();
            var roots = await _farmmapsApiService.GetCurrentUserRootsAsync();

            //Where to write the output
            string downloadFolder = fieldsInputs[0].DownloadFolder;
            if (string.IsNullOrEmpty(downloadFolder))
            {
                downloadFolder = "Downloads";
            }
            if (!Directory.Exists(downloadFolder))
                Directory.CreateDirectory(downloadFolder);

            //Write the same info to a single csv file. Note this means existing file will be overwritten!
            StreamWriter sw; string KPIItemPathCsv = Path.Combine(downloadFolder, "KPIItems.csv");
            List<string> headerList = new List<string> { "parentName", "area_ha", "cropTypeCode", "cropTypeName", "KPIid", "KPIvariable", "KPIvalue", "KPIunit", "KPItargetvalue", "KPIthresholdValue" };
            //Create a new csv file. Means if existing then overwritten !!!
            sw = new StreamWriter(KPIItemPathCsv);
            sw.WriteLine(string.Join(",", headerList));

            //Now loop through the list of cropfields in KPIinput.json and get the KPI's for each cropfield
            foreach (var input in fieldsInputs)
            {
                try
                {
                    await Process(roots, input, sw);
                }
                catch (Exception ex)
                {
                    _logger.LogError(ex.Message);
                }
            }
            
            //Close the csv file, write message to screen
            sw.Close();
            _logger.LogInformation($"Done! Written all KPI for all fields in 'KPIinput.json' to output file '{KPIItemPathCsv}'");
        }

        private async Task Process(List<UserRoot> roots, KPIInput input, StreamWriter sw)
        {
            KPIOutput kpio;
            KPIOutput kpioPrevious = null;

            string downloadFolder = input.DownloadFolder;
            if (string.IsNullOrEmpty(downloadFolder)) {
                downloadFolder = "Downloads";
            }
            if (!Directory.Exists(downloadFolder))
                Directory.CreateDirectory(downloadFolder);

            // !!specify if you are using an already created cropfield:
            bool useExistingCropfieldWithChildren = input.UseExistingCropfieldWithChildren;
            int cropYear = input.CropYear;
            string fieldName = input.fieldName;
            string fieldGeom = input.GeometryJson.ToString(Formatting.None);

            //Settings
            string settingsfile = $"Settings_{fieldName}.json";
            LoadSettings(settingsfile);

            var uploadedRoot = roots.SingleOrDefault(r => r.Name == "USER_IN");
            if (uploadedRoot == null)
            {
                _logger.LogError("Could not find a needed root item");
                return;
            }

            var myDriveRoot = roots.SingleOrDefault(r => r.Name == "USER_FILES");
            if (myDriveRoot == null)
            {
                _logger.LogError("Could not find a needed root item");
                return;
            }

            // Use already created cropfield or create new one, added a Data input, with field specific data for the KPI calculation
            Item cropfieldItem;
            //1 useExistingCropfieldWithChildren = false -> create new
            //2 useExistingCropfieldWithChildren = true && input.CropfieldItemCode = "" or absent -> read from settings json
            //3 useExistingCropfieldWithChildren = true && input.CropfieldItemCode like "deb48a74c5b54299bb852f17288010e9" in KPIinput -> use this one
            if (useExistingCropfieldWithChildren == false)
            {
                _logger.LogInformation("Creating cropfield, writting to settings file");
                cropfieldItem = await _generalService.CreateCropfieldItemAsync(myDriveRoot.Code,
                    $"{fieldName}", cropYear, input.GeometryJson.ToString(Formatting.None), input.DataCropfield.ToString(Formatting.None));
                _settings.CropfieldItemCode = cropfieldItem.Code;
                SaveSettings(settingsfile);
            }
            else if (string.IsNullOrEmpty(input.CropfieldItemCode))
            {
                _logger.LogInformation("reading CropfieldItemCode from settings file");
                cropfieldItem = await _farmmapsApiService.GetItemAsync(_settings.CropfieldItemCode);
            }
            else
            {
                _logger.LogInformation("reading CropfieldItemCode from KPIinput.json");
                cropfieldItem = await _farmmapsApiService.GetItemAsync(input.CropfieldItemCode);
                SaveSettings(settingsfile);
            }


            // Use already created croprecording or create new one, added a Data input, with field specific data for the KPI calculation
            Item crprecItem;
            //1 useExistingCropfieldWithChildren = false -> create new
            //2 useExistingCropfieldWithChildren = true && input.CropRecordingItemCode = "" or absent -> read from settings json
            //3 useExistingCropfieldWithChildren = true && input.CropRecordingItemCode like "deb48a74c5b54299bb852f17288010e9" in KPIinput -> use this one
            if (useExistingCropfieldWithChildren == false)
            {
                _logger.LogInformation("RunCropRecordingTask ...");
                crprecItem = await _generalService.RunCropRecordingTask(cropfieldItem);
                _settings.CropRecordingItemCode = crprecItem.Code;
                SaveSettings(settingsfile);
            }
            else if (string.IsNullOrEmpty(input.CropfieldItemCode))
            {
                _logger.LogInformation("reading CropRecordingItemCode from settings file");
                crprecItem = await _farmmapsApiService.GetItemAsync(_settings.CropRecordingItemCode);
            }
            else
            {
                _logger.LogInformation("reading CropRecordingItemCode from KPIinput.json");
                crprecItem = await _farmmapsApiService.GetItemAsync(input.CropRecordingItemCode);
                SaveSettings(settingsfile);
            }

            // Use already created operations or create new one,s added a Data input, with field specific data for the KPI calculation
            List<Item> crpOperationItems = new List<Item> { };
            List<string> crpOperationItemCodes = new List<string> { };
            Item crpOperationItem;
            string dataOperation;
            string codeOperation;
            //1 useExistingCropfieldWithChildren = false -> create new
            //2 useExistingCropfieldWithChildren = true && input.OperationItemCode = "" or absent -> read from settings json
            //3 useExistingCropfieldWithChildren = true && input.OperationItemCode like "deb48a74c5b54299bb852f17288010e9" in KPIinput -> use this one
            if (useExistingCropfieldWithChildren == false)
            {
                for (int i = 0; i < input.DataOperations.Length; i++)
                {
                    dataOperation = input.DataOperations[i].ToString(Formatting.None);
                    dynamic data = JObject.Parse(dataOperation);
                    _logger.LogInformation($"CreateOperationItemAsync ... for operation {i}: '{data.name}', {data.n} kg N/ha, on date '{data.from}'");
                    crpOperationItem = await _generalService.CreateOperationItemAsync(crprecItem.Code, cropYear, fieldGeom, dataOperation);
                    crpOperationItems.Add(crpOperationItem);
                    crpOperationItemCodes.Add(crpOperationItem.Code);
                }
                _settings.OperationItemCodes = crpOperationItemCodes.ToArray();
                SaveSettings(settingsfile);
            }
            else if (string.IsNullOrEmpty(input.CropfieldItemCode))
            {
                _logger.LogInformation("reading OperationItemCode from settings file");
                for (int i = 0; i < _settings.OperationItemCodes.Length; i++)
                {
                    codeOperation = _settings.OperationItemCodes[i];
                    crpOperationItem = await _farmmapsApiService.GetItemAsync(codeOperation);
                    crpOperationItems.Add(crpOperationItem);
                    crpOperationItemCodes.Add(crpOperationItem.Code);
                }
            }
            else
            {
                _logger.LogInformation("reading OperationItemCodes from KPIinput.json");
                for (int i = 0; i < input.OperationItemCodes.Length; i++)
                {
                    codeOperation = input.OperationItemCodes[i];
                    crpOperationItem = await _farmmapsApiService.GetItemAsync(codeOperation);
                    crpOperationItems.Add(crpOperationItem);
                    crpOperationItemCodes.Add(crpOperationItem.Code);
                }
                _settings.OperationItemCodes = crpOperationItemCodes.ToArray();
                SaveSettings(settingsfile);
            }

            // The cropfieldCharacteristicItem is used to enter crop yields
            // So once we have added an operation for fertilizer application and a crop yield, then KPIapp can calculate
            // Nutrient balance.
            // Use already created cropfieldCharacteristicItem or create new one, added a Data input, with field specific data for the KPI calculation
            Item cropfieldCharacteristicItem;
            //1 useExistingCropfieldWithChildren = false -> create new
            //2 useExistingCropfieldWithChildren = true && input.CropfieldCharacteristicItemCode = "" or absent -> read from settings json
            //3 useExistingCropfieldWithChildren = true && input.CropfieldCharacteristicItemCode like "deb48a74c5b54299bb852f17288010e9" in KPIinput -> use this one
            if (useExistingCropfieldWithChildren == false)
            {
                _logger.LogInformation("CreateCropfieldCharacteristicItemAsync ...");
                cropfieldCharacteristicItem = await _generalService.CreateCropfieldCharacteristicItemAsync(cropfieldItem.Code, cropYear, fieldGeom, input.DataCropfieldCharacteristic.ToString(Formatting.None));
                _settings.CropfieldCharacteristicItemCode = cropfieldCharacteristicItem.Code;
                SaveSettings(settingsfile);
            }
            else if (string.IsNullOrEmpty(input.CropfieldItemCode))
            {
                _logger.LogInformation("reading OperationItemCode from settings file");
                cropfieldCharacteristicItem = await _farmmapsApiService.GetItemAsync(_settings.CropfieldCharacteristicItemCode);
            }
            else
            {
                _logger.LogInformation("reading CropfieldCharacteristicItemCode from KPIinput.json");
                cropfieldCharacteristicItem = await _farmmapsApiService.GetItemAsync(input.CropfieldCharacteristicItemCode);
                SaveSettings(settingsfile);
            }

            // Inspect the children and grandchildren. If all is well, cropfield will have:
            // one crprec, with 0-many operations as children. And the Data of an operation will have specification of how much fertilizer was applied
            // one edicrop.characteristic (with yield in the data)
            var cropfieldChildren = await _farmmapsApiService.GetItemChildrenAsync(cropfieldItem.Code);
            var crprecChildren = await _farmmapsApiService.GetItemChildrenAsync(crprecItem.Code);

            //Now get the KPIs for this cropfield, mounted with operations & cropyield
            // Get KPI data for saving it in a file, here the generalsedrvice is called to get the KPI data
            _logger.LogInformation($"GetKpiItemsForCropField('{cropfieldItem.Code}')");
            List<Item> KPIItems = await _generalService.GetKpiItemsForCropField(cropfieldItem);
            _logger.LogInformation($"Found {KPIItems.Count} KPI items");

            //Download KPI's into a json output file for this specific cropfield (with unique cropfieldItem.Code)
            string KPIItemPathJson = Path.Combine(downloadFolder, $"KPIItems_{cropfieldItem.Code}.json");
            var count = 0;
            foreach (Item item in KPIItems)
            {
                //Console.WriteLine($"KPI item #{count}: {item.Name}");
                File.AppendAllText(KPIItemPathJson, item.Data + Environment.NewLine);
                count++;
            }
            _logger.LogInformation($"Downloaded file {KPIItemPathJson}");

            //Write to the csv file that collects all KPI's for all the crop fields
            List<string> dataList; 
            foreach (Item item in KPIItems)
            {
                dataList = new List<string> { };
                kpio = JsonConvert.DeserializeObject<KPIOutput>(item.Data.ToString());
                //Seems sometimes duplicate KPI items are returned. So check that here and only write if this kpio is different from previous
                if (kpio != kpioPrevious)
                {
                    dataList.Add(kpio.parentName);
                    dataList.Add(kpio.data.area);
                    dataList.Add(kpio.data.cropTypeCode);
                    dataList.Add(kpio.data.cropTypeName);
                    dataList.Add(kpio.id);
                    dataList.Add(kpio.quantity);
                    dataList.Add(kpio.value);
                    dataList.Add(kpio.unit);
                    dataList.Add(kpio.targetValue);
                    dataList.Add(kpio.thresholdValue);
                    sw.WriteLine(string.Join(",", dataList));
                }
                kpioPrevious = kpio;
            }

            //Clean up. Only newly created fields 
            //Look up instruction in Swagger / api / v1 / items /{ code}
            if (useExistingCropfieldWithChildren == false && input.DeleteNewlyCreatedAfterCalc == true)
            {
                // Tested and found that if I delete the parent (cropfieldItem) then
                // automatically deletes children (crprecItem, cropfieldCharacteristicItem, KPIcontainer)
                // and automatically deletes grand children (crprecItem: operations, KPIcontainer: KPI items)
                await _farmmapsApiService.DeleteItemAsync(cropfieldItem.Code);
                //Do we need to wait here for the task to be completed? Or does it continue in the background?
                //await Task.Delay(60000); // wait 60 secs for task to be completed
                //Before the GetItem you will see cropfieldItem, crprecItem etc exist (with data).
                //After the GetItem these  cropfieldItem, crprecItem etc are null which means they have been succesfully deleted.
                //// Check if below works, i.e. is item really deleted?
                //cropfieldItem = await _farmmapsApiService.GetItemAsync(cropfieldItem.Code);
                //// Check if croprecording has also been deleted. If not also delete it
                //crprecItem = await _farmmapsApiService.GetItemAsync(crprecItem.Code);
                //// Check if 1 operation has also been deleted. If not also delete it
                //crpOperationItem = await _farmmapsApiService.GetItemAsync(crpOperationItemCodes[0]);
                //// Check if 1 cropfieldCharacteristicItem has also been deleted. If not also delete it
                //cropfieldCharacteristicItem = await _farmmapsApiService.GetItemAsync(cropfieldCharacteristicItem.Code);
            }
        }

        // Functions to save previously created cropfields
        private void LoadSettings(string file)
        {
            if (File.Exists(file))
            {
                var jsonText = File.ReadAllText(file);
                _settings = JsonConvert.DeserializeObject<Settings>(jsonText);
            }
            else
            {
                _settings = new Settings();
            }
        }

        private void SaveSettings(string file)
        {
            if (_settings == null)
                return;

            var json = JsonConvert.SerializeObject(_settings);
            File.WriteAllText(file, json);
        }
        private void SaveInfo(string file)
        {
            if (_settings == null)
                return;

            var json = JsonConvert.SerializeObject(_settings);
            File.WriteAllText(file, json);

        }

    }
}