using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using DSharpPlus;
using DSharpPlus.Entities;
using DSharpPlus.EventArgs;
using DSharpPlus.Exceptions;
using DSharpPlus.SlashCommands;
using DSharpPlus.SlashCommands.Attributes;
using DSharpPlus.SlashCommands.EventArgs;
using Breadcraft.Commands;

namespace Breadcraft;

internal static class EventHandler
{
	internal static Task OnReady(DiscordClient client, ReadyEventArgs e)
	{
		Logger.Log("Client is ready to process events.");

		// Checking activity type
		if (!Enum.TryParse(Config.presenceType, true, out ActivityType activityType))
		{
			Logger.Log("Presence type '" + Config.presenceType + "' invalid, using 'Playing' instead.");
			activityType = ActivityType.Playing;
		}

		client.UpdateStatusAsync(new DiscordActivity(Config.presenceText, activityType), UserStatus.Online);
		return Task.CompletedTask;
	}

	internal static Task OnGuildAvailable(DiscordClient _, GuildCreateEventArgs e)
	{
		Logger.Log("Guild available: " + e.Guild.Name);

		IReadOnlyDictionary<ulong, DiscordRole> roles = e.Guild.Roles;

		foreach ((ulong roleID, DiscordRole role) in roles)
		{
			Logger.Log(role.Name.PadRight(40, '.') + roleID);
		}
		return Task.CompletedTask;
	}

	internal static Task OnClientError(DiscordClient _, ClientErrorEventArgs e)
	{
		Logger.Error("Client exception occured:\n" + e.Exception);
		switch (e.Exception)
		{
			case BadRequestException ex:
				Logger.Error("JSON Message: " + ex.JsonMessage);
				break;
		}
		return Task.CompletedTask;
	}

	internal static async Task OnMessageCreated(DiscordClient client, MessageCreateEventArgs e)
	{
		if (e.Author.IsBot)
		{
			return;
		}

		// Check if ticket exists in the database and ticket notifications are enabled
		if (!Database.TryGetOpenTicket(e.Channel.Id, out Database.Ticket ticket) || !Config.ticketUpdatedNotifications)
		{
			return;
		}

		// Sends a DM to the assigned staff member if at least a day has gone by since the last message and the user sending the message isn't staff
		IReadOnlyList<DiscordMessage> messages = await e.Channel.GetMessagesAsync(2);
		if (messages.Count > 1 && messages[1].Timestamp < DateTimeOffset.UtcNow.AddDays(Config.ticketUpdatedNotificationDelay * -1) && !Database.IsStaff(e.Author.Id))
		{
			try
			{
				DiscordMember staffMember = await e.Guild.GetMemberAsync(ticket.assignedStaffID);
				await staffMember.SendMessageAsync(new DiscordEmbedBuilder
				{
					Color = DiscordColor.Green,
					Description = "A ticket you are assigned to has been updated: " + e.Channel.Mention
				});
			}
			catch (NotFoundException) { }
			catch (UnauthorizedException) { }
		}
	}

	internal static async Task OnCommandError(SlashCommandsExtension commandSystem, SlashCommandErrorEventArgs e)
	{
		switch (e.Exception)
		{
			case SlashExecutionChecksFailedException checksFailedException:
			{
				foreach (SlashCheckBaseAttribute attr in checksFailedException.FailedChecks)
				{
					await e.Context.Channel.SendMessageAsync(new DiscordEmbedBuilder
					{
						Color = DiscordColor.Red,
						Description = ParseFailedCheck(attr)
					});
				}
				return;
			}
				
			case BadRequestException ex:
				Logger.Error("Command exception occured:\n" + e.Exception);
				Logger.Error("JSON Message: " + ex.JsonMessage);
				return;

			default:
			{
				Logger.Error("Exception occured: " + e.Exception.GetType() + ": " + e.Exception);
				await e.Context.Channel.SendMessageAsync(new DiscordEmbedBuilder
				{
					Color = DiscordColor.Red,
					Description = "Internal error occured, please report this to the developer."
				});
				return;
			}
		}
	}

	internal static async Task OnMemberAdded(DiscordClient client, GuildMemberAddEventArgs e)
	{
		if (!Database.TryGetOpenTickets(e.Member.Id, out List<Database.Ticket> ownTickets))
		{
			return;
		}

		foreach (Database.Ticket ticket in ownTickets)
		{
			try
			{
				DiscordChannel channel = await client.GetChannelAsync(ticket.channelID);
				if (channel?.GuildId == e.Guild.Id)
				{
					await channel.SendMessageAsync(new DiscordEmbedBuilder
					{
						Color = DiscordColor.Green,
						Description = "User '" + e.Member.Username + "#" + e.Member.Discriminator + "' has rejoined the server, and has been re-added to the ticket."
					});
				}
			}
			catch (Exception) { /* ignored */ }
		}
	}

	internal static async Task OnMemberRemoved(DiscordClient client, GuildMemberRemoveEventArgs e)
	{
		if (Database.TryGetOpenTickets(e.Member.Id, out List<Database.Ticket> ownTickets))
		{
			foreach(Database.Ticket ticket in ownTickets)
			{
				try
				{
					DiscordChannel channel = await client.GetChannelAsync(ticket.channelID);
					if (channel?.GuildId == e.Guild.Id)
					{
						await channel.SendMessageAsync(new DiscordEmbedBuilder
						{
							Color = DiscordColor.Red,
							Description = "User '" + e.Member.Username + "#" + e.Member.Discriminator + "' has left the server."
						});
					}
				}
				catch (Exception) { /* ignored */ }
			}
		}

		if (Database.TryGetAssignedTickets(e.Member.Id, out List<Database.Ticket> assignedTickets) && Config.logChannel != 0)
		{
			DiscordChannel logChannel = await client.GetChannelAsync(Config.logChannel);
			if (logChannel != null)
			{
				foreach (Database.Ticket ticket in assignedTickets)
				{
					try
					{
						DiscordChannel channel = await client.GetChannelAsync(ticket.channelID);
						if (channel?.GuildId == e.Guild.Id)
						{
							await logChannel.SendMessageAsync(new DiscordEmbedBuilder
							{
								Color = DiscordColor.Red,
								Description = "Assigned staff member '" + e.Member.Username + "#" + e.Member.Discriminator + "' has left the server: <#" + channel.Id + ">"
							});
						}
					}
					catch (Exception) { /* ignored */ }
				}
			}
		}
	}

	internal static async Task OnComponentInteractionCreated(DiscordClient client, ComponentInteractionCreateEventArgs e)
	{
		try
		{
			switch (e.Interaction.Data.ComponentType)
			{
				case ComponentType.Button:
					switch (e.Id)
					{
						case "breadcraft_closeconfirm":
							await CloseCommand.OnConfirmed(e.Interaction);
							return;
						case {} when e.Id.StartsWith("breadcraft_newcommandbutton"):
							await NewCommand.OnCategorySelection(e.Interaction);
							return;
						case {} when e.Id.StartsWith("breadcraft_newticketbutton"):
							await CreateButtonPanelCommand.OnButtonUsed(e.Interaction);
							return;
						case "right":
							return;
						case "left":
							return;
						case "rightskip":
							return;
						case "leftskip":
							return;
						case "stop":
							return;
						default:
							Logger.Warn("Unknown button press received! '" + e.Id + "'");
							return;
					}
				case ComponentType.Select:
					switch (e.Id)
					{
						case {} when e.Id.StartsWith("breadcraft_newcommandselector"):
							await NewCommand.OnCategorySelection(e.Interaction);
							return;
						case {} when e.Id.StartsWith("breadcraft_newticketselector"):
							await CreateSelectionBoxPanelCommand.OnSelectionMenuUsed(e.Interaction);
							return;
						default:
							Logger.Warn("Unknown selection box option received! '" + e.Id + "'");
							return;
					}
				case ComponentType.ActionRow:
					Logger.Warn("Unknown action row received! '" + e.Id + "'");
					return;
				case ComponentType.FormInput:
					Logger.Warn("Unknown form input received! '" + e.Id + "'");
					return;
				default:
					Logger.Warn("Unknown interaction type received! '" + e.Interaction.Data.ComponentType + "'");
					break;
			}
		}
		catch (DiscordException ex)
		{
			Logger.Error("Interaction Exception occurred: " + ex);
			Logger.Error("JsomMessage: " + ex.JsonMessage);
		}
		catch (Exception ex)
		{
			Logger.Error("Interaction Exception occured: " + ex.GetType() + ": " + ex);
		}
	}
		
	private static string ParseFailedCheck(SlashCheckBaseAttribute attr)
	{
		return attr switch
		{
			SlashRequireDirectMessageAttribute => "This command can only be used in direct messages!",
			SlashRequireOwnerAttribute => "Only the server owner can use that command!",
			SlashRequirePermissionsAttribute => "You don't have permission to do that!",
			SlashRequireBotPermissionsAttribute => "The bot doesn't have the required permissions to do that!",
			SlashRequireUserPermissionsAttribute => "You don't have permission to do that!",
			SlashRequireGuildAttribute => "This command has to be used in a Discord server!",
			_ => "Unknown Discord API error occured, please try again later."
		};
	}
}