using System;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using FarmmapsApi;
using FarmmapsApi.Models;
using FarmmapsApi.Services;
using FarmmapsHaulmkilling.Models;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using static FarmmapsApiSamples.Constants;

namespace FarmmapsHaulmkilling
{
    public class HaulmkillingApplication : IApplication
    {
        private const string DownloadFolder = "Downloads";
        private const string SettingsFile = "settings.json";

        private readonly ILogger<HaulmkillingApplication> _logger;
        private readonly FarmmapsApiService _farmmapsApiService;
        private readonly HaulmkillingService _haulmkillingService;
        private readonly GeneralService _generalService;

        private Settings _settings;
        
        public HaulmkillingApplication(ILogger<HaulmkillingApplication> logger, FarmmapsApiService farmmapsApiService,
            GeneralService generalService, HaulmkillingService haulmkillingService)
        {
            _logger = logger;
            _farmmapsApiService = farmmapsApiService;
            _generalService = generalService;
            _haulmkillingService = haulmkillingService;
        }
        
        public async Task RunAsync()
        {
            if (!Directory.Exists(DownloadFolder))
                Directory.CreateDirectory(DownloadFolder);

            LoadSettings();
            
            // !! 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();

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

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

            var agents = await _haulmkillingService.GetHaulmkillingAgents();
            if (agents == null || agents.Count == 0)
            {
                _logger.LogError("No valid agents found for haulmkilling");
                return;
            }

            Item cropfieldItem;
            if (string.IsNullOrEmpty(_settings.CropfieldItemCode))
            {
                _logger.LogInformation("Creating cropfield");
                cropfieldItem = await _generalService.CreateCropfieldItemAsync(myDrive.Code, "Cropfield VRA Haulmkilling", 2020, 
                    @"{""type"":""Polygon"",""coordinates"":[[[4.617786844284247,52.22533706956424],[4.618642601314543,52.225938364585989],[4.6192153806397,52.22563988897754],[4.619192414656403,52.2256242822442],[4.620306732153958,52.225031745661528],[4.620542019225217,52.22519855319158],[4.621157509147853,52.22487436515405],[4.623387917230182,52.22367660757213],[4.624563444939009,52.22304740241544],[4.624562779355982,52.223046635247019],[4.624534908813479,52.22302596787506],[4.627873021330343,52.221240670658399],[4.627504935938338,52.220104419135129],[4.627324878706837,52.22020569669098],[4.627320696113512,52.22020660117888],[4.626707169518044,52.22053923770041],[4.624700376420229,52.221619047547488],[4.623471571183885,52.22227447969577],[4.623471511010673,52.22227500174403],[4.623468838689317,52.22228052566992],[4.617786844284247,52.22533706956424]]]}");
                _settings.CropfieldItemCode = cropfieldItem.Code;
                SaveSettings();
            }
            else
            {
                _logger.LogInformation("Cropfield already exists trying to get");
                cropfieldItem = await _farmmapsApiService.GetItemAsync(_settings.CropfieldItemCode);
            }

            ItemTaskStatus taskStatus;
            if (string.IsNullOrEmpty(_settings.SatelliteTaskCode))
            {
                _logger.LogInformation("Gathering satellite information for cropfield, this might take a while!");
                taskStatus = await _generalService.RunAndWaitForTask(cropfieldItem, SATELLITE_TASK, null, 20);

                if (taskStatus.State == ItemTaskState.Error)
                {
                    _logger.LogError($"Something went wrong when trying to process satellite data; {taskStatus.Message}");
                    return;
                }

                _settings.SatelliteTaskCode = taskStatus.Code;
                SaveSettings();

            }
            else
            {
                taskStatus = await _farmmapsApiService.GetTaskStatusAsync(_settings.CropfieldItemCode, _settings.SatelliteTaskCode);
            }

            // find ndvi or wdvi satellite data geotiffs
            var temporalItem = await _generalService.FindChildItemAsync(cropfieldItem.Code, TEMPORAL_ITEMTYPE,
                "Cropfield VRA Haulmkilling, Satellite", item => item.SourceTask == SATELLITE_TASK && 
                                                                 taskStatus.Finished >= item.Created && 
                                                                 taskStatus.Finished <= item.Created.Value.AddHours(1));
            
            if (temporalItem == null)
            {
                _logger.LogError("Temporal item not found");
                return;
            }

            var satelliteTiffs = await _farmmapsApiService.GetItemChildrenAsync(temporalItem.Code);
            var firstSatelliteItem = satelliteTiffs.FirstOrDefault();

            if (firstSatelliteItem == null)
            {
                _logger.LogError("Satellite item not found");
                return;
            }
            
            // must be ndvi or wdvi
            var inputType = (firstSatelliteItem.Data["layers"] as JArray)?[0]["name"].ToString();
            if (string.IsNullOrEmpty(inputType))
            {
                _logger.LogError("Could not get the input type name from the satellite item");
                return;
            }
            
            var selectedAgent = agents[0];
            var selectedOption = selectedAgent.ValidOptions[0];
            
            _logger.LogInformation("Calculating application map");
            var applianceMapItem = await _haulmkillingService.CalculateApplicationMapAsync(cropfieldItem, 
                firstSatelliteItem, inputType, selectedOption, selectedAgent);
            if (applianceMapItem == null)
            {
                return;
            }
            
            _logger.LogInformation("Downloading application map");
            await _farmmapsApiService.DownloadItemAsync(applianceMapItem.Code, Path.Combine(DownloadFolder, 
                $"{applianceMapItem.Name}_{Guid.NewGuid():N}.zip"));
        }

        private void LoadSettings()
        {
            if (File.Exists(SettingsFile))
            {
                var jsonText = File.ReadAllText(SettingsFile);
                _settings = JsonConvert.DeserializeObject<Settings>(jsonText);
            }
            else
            {
                _settings = new Settings();
            }
        }

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

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