import {
    ActionRowBuilder,
    ButtonBuilder,
    ButtonStyle,
    ChannelType,
    ForumChannel,
    PermissionFlagsBits,
    SlashCommandBuilder,
    SlashCommandChannelOption,
    SlashCommandStringOption,
    SlashCommandUserOption,
    ChatInputCommandInteraction,
    type ButtonInteraction,
    type GuildForumTag,
    type GuildBasedChannel,
} from "discord.js";

export let slashCommands = [
    {
        slashCommand: new SlashCommandBuilder()
            .setName("new")
            .setDescription("Create a new CTF")
            .addStringOption(
                new SlashCommandStringOption()
                    .setName("name")
                    .setDescription("Name for the new CTF")
                    .setRequired(true)
            )
            .addStringOption(
                new SlashCommandStringOption()
                    .setName("message")
                    .setDescription("Contents of the initial post in the general thread. Should probably be a link to the CTF platform.")
                    .setRequired(true)
            )
            .addStringOption(
                new SlashCommandStringOption()
                    .setName("tags")
                    .setDescription("A comma-separated list of tags to add to the forum. Defaults to the most common CTF categories.")
            ),
        handler: newCtf,
    },
    {
        slashCommand: new SlashCommandBuilder()
            .setName("create-button-message")
            .setDescription("Re-create a message containing an invite button for this CTF")
            .addChannelOption(
                new SlashCommandChannelOption()
                    .setName("channel")
                    .setDescription("The channel in which to create the button")
                    .setRequired(true)
            ),
        handler: createButtonMessage,
    },
    {
        slashCommand: new SlashCommandBuilder()
            .setName("archive")
            .setDescription("Make this CTF forum read-only for everyone"),
        handler: archiveCtf,
    },
    {
        slashCommand: new SlashCommandBuilder()
            .setName("add")
            .setDescription("Add a user to this CTF forum")
            .addUserOption(
                new SlashCommandUserOption()
                    .setName("user")
                    .setDescription("The user to add")
                    .setRequired(true)
            ),
        handler: addToCtf,
    },
    {
        slashCommand: new SlashCommandBuilder()
            .setName("remove")
            .setDescription("Remove a user from this CTF forum")
            .addUserOption(
                new SlashCommandUserOption()
                    .setName("user")
                    .setDescription("The user to remove")
                    .setRequired(true)
            ),
        handler: removeFromCtf,
    },
];

export let buttonCommands = {
    join: {
        prefix: "ctf-forum:",
        handler: handleJoinCtfButton,
    },
} as const;

async function newCtf(interaction: ChatInputCommandInteraction) {
    if (!interaction.guild) {
        await interaction.reply({
            content: "This command can only be used inside a server.",
            flags: "Ephemeral",
        });
        return;
    }

    let name = interaction.options.getString("name", true);
    let link = interaction.options.getString("message", true);
    let tags = interaction.options.getString("tags");
    await interaction.deferReply({ flags: "Ephemeral" });

    let forum = await interaction.guild.channels.create({
        name,
        type: ChannelType.GuildForum,
        permissionOverwrites: [
            {
                id: interaction.guild.roles.everyone,
                deny: [PermissionFlagsBits.ViewChannel],
            }
        ],
    });

    await forum.setAvailableTags((tags?.split(",") ?? ["web", "pwn", "rev", "crypto"]).map(name => ({ name, moderated: false })));

    await ensureUnsolvedTag(forum);

    let generalThread = await forum.threads.create({
        name: "general",
        message: {
            content: link,
        },
    });

    await generalThread.pin();

    let commandChannel = (interaction.channelId && await interaction.guild.channels.fetch(interaction.channelId));

    if (!commandChannel || !commandChannel.isTextBased())
        throw new Error("Wth is this channel?");

    await commandChannel.send({
        components: [
            new ActionRowBuilder<ButtonBuilder>().addComponents(
                new ButtonBuilder()
                    .setCustomId(`${buttonCommands.join.prefix}${forum.id}`)
                    .setLabel(`Join ${name}`)
                    .setStyle(ButtonStyle.Primary),
            ),
        ],
    });

    await interaction.editReply(
        `Created ${forum.name}.`,
    );
}

async function createButtonMessage(interaction: ChatInputCommandInteraction) {
    let forum = await getCtfForum(interaction);

    let channel = interaction.options.getChannel("channel", true, [ChannelType.GuildText]);

    await channel.send({
        components: [
            new ActionRowBuilder<ButtonBuilder>().addComponents(
                new ButtonBuilder()
                    .setCustomId(`${buttonCommands.join.prefix}${forum.id}`)
                    .setLabel(`Join ${forum.name}`)
                    .setStyle(ButtonStyle.Primary),
            ),
        ],
    });

    await interaction.reply({ content: "Done!", flags: "Ephemeral" });
}

async function archiveCtf(interaction: ChatInputCommandInteraction) {
    if (!interaction.guild) {
        await interaction.reply({
            content: "This command can only be used inside a server.",
            flags: "Ephemeral",
        });
        return;
    }

    let forum = await getCtfForum(interaction);

    let everyoneRoleId = interaction.guild.roles.everyone.id;

    await forum.permissionOverwrites.edit(everyoneRoleId, {
        ViewChannel: true,
        SendMessages: false,
        SendMessagesInThreads: false,
        CreatePublicThreads: false,
        CreatePrivateThreads: false,
    });

    await Promise.all(
        forum.permissionOverwrites.cache
            .filter(overwrite => overwrite.id !== everyoneRoleId)
            .map(overwrite => forum.permissionOverwrites.delete(overwrite.id))
    );

    let channels = await interaction.guild.channels.fetch();
    let archiveCategory = channels.find(
        channel => channel?.type === ChannelType.GuildCategory && ["Archive", "archive"].includes(channel.name)
    );

    if (archiveCategory) {
        await forum.setParent(archiveCategory.id, { lockPermissions: false });
    }

    await interaction.reply({
        content: `Updated ${forum.name}: @everyone can read, (mostly) no-one can write.`,
        flags: "Ephemeral",
    });
}

async function addToCtf(interaction: ChatInputCommandInteraction) {
    if (!interaction.guild) {
        await interaction.reply({
            content: "This command can only be used inside a server.",
            flags: "Ephemeral",
        });
        return;
    }

    let user = interaction.options.getUser("user", true);
    let forum = await getCtfForum(interaction);

    let member = await interaction.guild.members.fetch(interaction.user.id);
    let permissions = forum.permissionsFor(member);

    if (!permissions?.has(PermissionFlagsBits.ManageChannels)) {
        await interaction.reply({
            content: `You don't have permission to update permissions in ${forum.name}.`,
            flags: "Ephemeral",
        });
        return;
    }

    await forum.permissionOverwrites.edit(user, {
        ViewChannel: true,
        CreatePublicThreads: true,
        SendMessages: true,
        SendMessagesInThreads: true,
    });

    await interaction.reply({
        content: `Granted ${user} access to ${forum.name}.`,
        flags: "Ephemeral",
    });
}

async function removeFromCtf(interaction: ChatInputCommandInteraction) {
    if (!interaction.guild) {
        await interaction.reply({
            content: "This command can only be used inside a server.",
            flags: "Ephemeral",
        });
        return;
    }

    let user = interaction.options.getUser("user", true);
    let forum = await getCtfForum(interaction);

    let member = await interaction.guild.members.fetch(interaction.user.id);
    let permissions = forum.permissionsFor(member);

    if (!permissions?.has(PermissionFlagsBits.ManageChannels)) {
        await interaction.reply({
            content: `You don't have permission to update permissions in ${forum.name}.`,
            flags: "Ephemeral",
        });
        return;
    }

    await forum.permissionOverwrites.delete(user.id);

    await interaction.reply({
        content: `Removed ${user} from ${forum.name}.`,
        flags: "Ephemeral",
    });
}

async function handleJoinCtfButton(interaction: ButtonInteraction, forumId: string) {
    if (!interaction.guild) {
        return await interaction.reply({
            content: "This button only works inside a server.",
            flags: "Ephemeral",
        });
    }

    let forumChannel = await interaction.guild.channels.fetch(forumId);

    if (!forumChannel || forumChannel.type !== ChannelType.GuildForum) {
        await interaction.reply({
            content: "That forum no longer exists.",
            flags: "Ephemeral",
        });
        return;
    }

    if (forumChannel.permissionsFor(interaction.guild.roles.everyone).has(PermissionFlagsBits.ViewChannel)) {
        await interaction.reply({
            content: `The CTF has been archived so you can already view it: https://discord.com/channels/${interaction.guild.id}/${forumChannel.id}`,
            flags: "Ephemeral",
        });
        return;
    }

    await forumChannel.permissionOverwrites.edit(interaction.user.id, {
        ViewChannel: true,
        CreatePublicThreads: true,
        SendMessages: true,
        SendMessagesInThreads: true,
    });

    await interaction.reply({
        content: `Granted you access to https://discord.com/channels/${interaction.guild.id}/${forumChannel.id}`,
        flags: "Ephemeral",
    });
}

/**
 * Given either a forum, a thread in a forum, or an interaction from a slash command ran in a thread
 * in a forum, returns that forum if it was created by this bot.
 */
export async function getCtfForum(interactionOrChannel: ChatInputCommandInteraction | GuildBasedChannel): Promise<ForumChannel> {
    let interaction = (interactionOrChannel instanceof ChatInputCommandInteraction) ? interactionOrChannel : null;
    async function done(): Promise<never> {
        await interaction?.reply({ content: "This command can only be used in a CTF forum channel.", flags: "Ephemeral" });
        throw "done";
    }

    let channel: GuildBasedChannel;
    if (interactionOrChannel instanceof ChatInputCommandInteraction) {
        if (!interactionOrChannel.guild) throw await done();

        let ch = await interactionOrChannel.guild.channels.fetch(interactionOrChannel.channelId);

        if (!ch) throw await done();

        channel = ch;
    } else {
        channel = interactionOrChannel;
    }

    if (channel.type === ChannelType.GuildForum) {
        return channel as ForumChannel;
    }
    if (!channel.isThread() || !channel.parentId)
        throw await done();

    let parent = await channel.guild.channels.fetch(channel.parentId);
    if (!parent || parent.type !== ChannelType.GuildForum)
        throw await done();

    let threads = await parent.threads.fetch();
    for (let thread of threads.threads.values()) {
        if (thread.name !== "general" ||
            thread.ownerId !== channel.client.user?.id ||
            !thread.flags.has("Pinned")) {
            continue;
        }

        return parent as ForumChannel;
    }

    throw await done();
}

export async function ensureUnsolvedTag(forum: ForumChannel): Promise<GuildForumTag> {
    let currentTags = forum.availableTags ?? [];
    let existing = currentTags.find(tag => tag.name === "unsolved");
    if (existing) {
        return existing;
    }

    await forum.setAvailableTags([
        ...currentTags,
        { name: "unsolved", moderated: false },
    ]);

    let updated = forum.availableTags?.find(tag => tag.name === "unsolved");
    if (!updated) {
        throw new Error(`Failed to create unsolved tag for ${forum.id}`);
    }

    return updated;
}