using cwebplusApp.Shared.Models;
using Microsoft.JSInterop;
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace cwebplusApp.Shared.Services {
    public sealed class ReportRepositoryService {

        private const string KeyNameFoundReports = "foundReportRepository";
        private const string KeyNameMissingReports = "missingReportRepository";
        private readonly IJSRuntime jsRuntime;
        private bool initialized;

        public event EventHandler Changed;

        public ReportRepositoryService(IJSRuntime jsRuntime) {
            this.jsRuntime = jsRuntime;
        }

        public async Task SaveReport(ReportRepositoryItem reportRepositoryItem) {
            if (reportRepositoryItem is FoundReportRepositoryItem fItem) {
                await SaveFoundReport(fItem);
            } else if (reportRepositoryItem is MissingReportRepositoryItem mItem) {
                await SaveMissingReport(mItem);
            }
        }

        public async ValueTask<List<FoundReportRepositoryItem>> GetFoundReports() {
            // Register the Storage event handler. This handler calls OnStorageUpdated when the storage changed.
            // This way, you can reload the settings when another instance of the application (tab / window) save the settings
            if (!initialized) {
                // Create a reference to the current object, so the JS function can call the public method "OnStorageUpdated"
                var reference = DotNetObjectReference.Create(this);
                await this.jsRuntime.InvokeVoidAsync("BlazorRegisterStorageEvent", reference);
                this.initialized = true;
            }

            // Read the JSON string that contains the data from the local storage
            List<FoundReportRepositoryItem> result;
            var str = await this.jsRuntime.InvokeAsync<string>("BlazorGetLocalStorage", KeyNameFoundReports);
            if (str != null) {
                result = JsonConvert.DeserializeObject<List<FoundReportRepositoryItem>>(str) ?? new();
            } else {
                result = new();
            }
            return result;
        }

        public async ValueTask<List<FoundReportRepositoryItem>> GetPendingFoundReports() {
            List<FoundReportRepositoryItem> pendingFoundReps = new();
            List<FoundReportRepositoryItem> foundReps = await GetFoundReports();
            foreach (FoundReportRepositoryItem report in foundReps) {
                if (!report.Transmitted) {
                    pendingFoundReps.Add(report);
                }
            }
            return pendingFoundReps;
        }

        public async ValueTask<List<MissingReportRepositoryItem>> GetMissingReports() {
            // Register the Storage event handler. This handler calls OnStorageUpdated when the storage changed.
            // This way, you can reload the settings when another instance of the application (tab / window) save the settings
            if (!initialized) {
                // Create a reference to the current object, so the JS function can call the public method "OnStorageUpdated"
                var reference = DotNetObjectReference.Create(this);
                await this.jsRuntime.InvokeVoidAsync("BlazorRegisterStorageEvent", reference);
                this.initialized = true;
            }

            // Read the JSON string that contains the data from the local storage
            List<MissingReportRepositoryItem> result;
            var str = await this.jsRuntime.InvokeAsync<string>("BlazorGetLocalStorage", KeyNameMissingReports);
            if (str != null) {
                result = JsonConvert.DeserializeObject<List<MissingReportRepositoryItem>>(str) ?? new();
            } else {
                result = new();
            }
            return result;
        }

        public async ValueTask<List<MissingReportRepositoryItem>> GetPendingMissingReports() {
            List<MissingReportRepositoryItem> pendingMissingReps = new();
            List<MissingReportRepositoryItem> missingReps = await GetMissingReports();
            foreach (MissingReportRepositoryItem report in missingReps) {
                if (!report.Transmitted) {
                    pendingMissingReps.Add(report);
                }
            }
            return pendingMissingReps;
        }

        public async Task SaveFoundReport(FoundReportRepositoryItem foundReportRepositoryItem) {
            List<FoundReportRepositoryItem> foundReps = await GetFoundReports();
            foundReps.Remove(foundReportRepositoryItem);
            foundReps.Add(foundReportRepositoryItem);
            var json = JsonConvert.SerializeObject(foundReps);
            await jsRuntime.InvokeVoidAsync("BlazorSetLocalStorage", KeyNameFoundReports, json);
        }

        public async Task SaveMissingReport(MissingReportRepositoryItem missingReportRepositoryItem) {
            List<MissingReportRepositoryItem> missingReps = await GetMissingReports();
            missingReps.Remove(missingReportRepositoryItem);
            missingReps.Add(missingReportRepositoryItem);
            var json = JsonConvert.SerializeObject(missingReps);
            await jsRuntime.InvokeVoidAsync("BlazorSetLocalStorage", KeyNameMissingReports, json);
        }

        public async ValueTask<int> GetNbrOfPendingReports() {
            List<FoundReportRepositoryItem> foundReportRepositoryItems = await GetPendingFoundReports();
            List<MissingReportRepositoryItem> missingReportRepositoryItems = await GetPendingMissingReports();
            return foundReportRepositoryItems.Count + missingReportRepositoryItems.Count;
        }

        // This method is called from BlazorRegisterStorageEvent when the storage changed
        [JSInvokable]
        public void OnStorageUpdated(string key) {
            if (key == KeyNameMissingReports || key == KeyNameFoundReports) {
                // Reset the settings. The next call to Get will reload the data
                Changed?.Invoke(this, EventArgs.Empty);
            }
        }

        public static long GetCurrentTimeInMillis() {
            return DateTime.Now.Ticks / TimeSpan.TicksPerMillisecond;
        }

        public static string GetCurrentDateTimeFromMillis(long millis) {
            TimeSpan time = TimeSpan.FromMilliseconds(millis);
            DateTime date = new DateTime() + time;
            return date.ToString("dd.MM.yyyy HH:mm:ss");
        }
    }
}