// Copyright (C) 2021-present sam (starshines.gay)
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

using System.Net;
using Catalogger.Backend.Api.Middleware;
using Catalogger.Backend.Bot;
using Catalogger.Backend.Database.Queries;
using Catalogger.Backend.Extensions;
using Catalogger.Backend.Services;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Remora.Discord.Extensions.Embeds;

namespace Catalogger.Backend.Api;

public partial class GuildsController
{
    [HttpPost("leave")]
    public async Task<IActionResult> LeaveGuildAsync(string id, [FromBody] LeaveGuildRequest req)
    {
        var (guildId, guild) = await ParseGuildAsync(id);
        if (guild.Name != req.Name)
        {
            throw new ApiError(
                HttpStatusCode.BadRequest,
                ErrorCode.BadRequest,
                "You must spell the server name correctly."
            );
        }

        var guildConfig = await db.GetGuildAsync(guildId.Value);
        var logChannelId =
            webhookExecutor.GetLogChannel(guildConfig, LogChannelType.GuildUpdate)
            ?? webhookExecutor.GetLogChannel(guildConfig, LogChannelType.GuildMemberRemove);
        if (logChannelId != null)
        {
            var currentUser = await discordRequestService.GetMeAsync(CurrentToken);

            var embed = new EmbedBuilder()
                .WithTitle("Catalogger is leaving this server")
                .WithDescription(
                    $"A moderator in this server ({currentUser.Tag}, <@{currentUser.Id}>) requested that Catalogger leave. "
                        + "All data related to this server will be deleted."
                )
                .WithColour(DiscordUtils.Red)
                .WithCurrentTimestamp()
                .Build()
                .GetOrThrow();

            await webhookExecutor.SendLogAsync(logChannelId.Value, [embed], []);
        }
        else
        {
            _logger.Information(
                "Can't send guild {GuildId} a heads up when leaving as neither the guild update nor member remove events are logged",
                guildId
            );
        }

        var leaveRes = await userApi.LeaveGuildAsync(guildId);
        if (!leaveRes.IsSuccess)
        {
            _logger.Error("Couldn't leave guild {GuildId}: {Error}", guildId, leaveRes.Error);
            throw new ApiError(
                HttpStatusCode.InternalServerError,
                ErrorCode.InternalServerError,
                "There was an error making Catalogger leave the server."
            );
        }

        await using var tx = await db.Database.BeginTransactionAsync();
        var inviteCount = await db
            .Invites.Where(i => i.GuildId == guildId.Value)
            .ExecuteDeleteAsync();
        var watchlistCount = await db
            .Watchlists.Where(w => w.GuildId == guildId.Value)
            .ExecuteDeleteAsync();
        var messageCount = await db
            .Messages.Where(m => m.GuildId == guildId.Value)
            .ExecuteDeleteAsync();
        await db.Guilds.Where(g => g.Id == guildId.Value).ExecuteDeleteAsync();
        await tx.CommitAsync();

        _logger.Information(
            "Deleted {InviteCount} invites, {WatchlistCount} watchlist entries, and {MessageCount} messages for guild {GuildId}",
            inviteCount,
            watchlistCount,
            messageCount,
            guildId
        );

        // Clear out the caches for this guild
        guildCache.Remove(guildId, out _);
        emojiCache.Remove(guildId);
        channelCache.RemoveGuild(guildId);
        roleCache.RemoveGuild(guildId);
        await memberCache.RemoveAllMembersAsync(guildId);
        await inviteCache.RemoveAsync(guildId);

        _logger.Information("Left guild {GuildId} and removed all data for it", guildId);

        return NoContent();
    }

    public record LeaveGuildRequest(string Name);
}