const {
    ChannelType,
    PermissionFlagsBits,
    ActionRowBuilder,
    ButtonBuilder,
    ButtonStyle,
} = require('discord.js');
const { createEmbed } = require('../utils/embeds');
const { Colors } = require('../config');
const { stmts } = require('../database');
const { logTicket } = require('./logger');

/**
 * Send the ticket embed with a "Create a Ticket" button to 🎫・open-ticket channel.
 */
async function sendTicketEmbed(client) {
    const row = await stmts.getState('channel_🎫・open-ticket');
    if (!row) throw new Error('Ticket channel not found in bot state.');

    const channel = await client.channels.fetch(row);
    if (!channel) throw new Error('Could not fetch ticket channel.');

    const embed = createEmbed({
        title: '🎫 Support Tickets',
        description: [
            '> Need help? Open a support ticket!',
            '',
            'Click the button below to create a private ticket.',
            '',
            '```',
            '• A private channel will be created for you',
            '• Staff will assist you as soon as possible',
            '• Only you and staff can see the ticket',
            '```',
        ].join('\n'),
        color: Colors.PRIMARY,
    });

    const actionRow = new ActionRowBuilder().addComponents(
        new ButtonBuilder()
            .setCustomId('ticket_create')
            .setLabel('Create a Ticket')
            .setEmoji('🎫')
            .setStyle(ButtonStyle.Primary),
    );

    const msg = await channel.send({ embeds: [embed], components: [actionRow] });

    await stmts.setState('ticket_message_id', msg.id);
    await stmts.setState('ticket_channel_id', channel.id);

    return msg;
}

/**
 * Create a ticket channel for a user.
 */
async function createTicket(guild, user, client) {
    // Check if user already has an open ticket
    const existing = await stmts.getUserTicket(user.id, 'open');
    if (existing) return null;

    const staffRole = guild.roles.cache.find(r => r.name === '@@ Staff');
    const ownerRole = guild.roles.cache.find(r => r.name === '@@ Owner');

    // Find the SUPPORT & TICKETS category
    const category = guild.channels.cache.find(
        c => c.type === ChannelType.GuildCategory && c.name.includes('SUPPORT')
    );

    const channelName = `ticket-${user.username.toLowerCase().replace(/[^a-z0-9]/g, '')}`;

    const overwrites = [
        { id: guild.id, deny: [PermissionFlagsBits.ViewChannel] },
        { id: user.id, allow: [PermissionFlagsBits.ViewChannel, PermissionFlagsBits.SendMessages, PermissionFlagsBits.ReadMessageHistory] },
    ];
    if (staffRole) overwrites.push({ id: staffRole.id, allow: [PermissionFlagsBits.ViewChannel, PermissionFlagsBits.SendMessages, PermissionFlagsBits.ReadMessageHistory, PermissionFlagsBits.ManageMessages] });
    if (ownerRole) overwrites.push({ id: ownerRole.id, allow: [PermissionFlagsBits.ViewChannel, PermissionFlagsBits.SendMessages, PermissionFlagsBits.ReadMessageHistory, PermissionFlagsBits.ManageMessages] });

    const ticketChannel = await guild.channels.create({
        name: channelName,
        type: ChannelType.GuildText,
        parent: category?.id,
        permissionOverwrites: overwrites,
    });

    // Save to database
    await stmts.createTicket(user.id, user.tag, ticketChannel.id);

    // Send welcome embed with action buttons
    const embed = createEmbed({
        title: '🎫 Ticket Opened',
        description: [
            `Welcome <@${user.id}>!`,
            '',
            'A staff member will be with you shortly.',
            'Please describe your issue below.',
            '',
            '> Use the buttons to manage this ticket.',
        ].join('\n'),
        color: Colors.PRIMARY,
    });

    const row = new ActionRowBuilder().addComponents(
        new ButtonBuilder()
            .setCustomId('ticket_close')
            .setLabel('Close Ticket')
            .setEmoji('🔒')
            .setStyle(ButtonStyle.Secondary),
        new ButtonBuilder()
            .setCustomId('ticket_transcript')
            .setLabel('Transcript')
            .setEmoji('📄')
            .setStyle(ButtonStyle.Primary),
        new ButtonBuilder()
            .setCustomId('ticket_delete')
            .setLabel('Delete Ticket')
            .setEmoji('🗑️')
            .setStyle(ButtonStyle.Danger),
    );

    await ticketChannel.send({ embeds: [embed], components: [row] });
    await logTicket(client, { user, action: 'opened', channelName });

    return ticketChannel;
}

/**
 * Generate a transcript of a ticket channel.
 */
async function generateTranscript(channel) {
    const messages = [];
    let lastId;

    // Fetch all messages (paginated)
    while (true) {
        const batch = await channel.messages.fetch({ limit: 100, ...(lastId ? { before: lastId } : {}) });
        if (batch.size === 0) break;
        messages.push(...batch.values());
        lastId = batch.last().id;
    }

    messages.reverse();

    const lines = messages.map(m => {
        const time = m.createdAt.toISOString().replace('T', ' ').slice(0, 19);
        return `[${time}] ${m.author.tag}: ${m.content || '(embed/attachment)'}`;
    });

    return lines.join('\n') || '(no messages)';
}

/**
 * Handle ticket button interactions.
 */
async function handleTicketButton(interaction, client) {
    const { customId, channel, guild, member } = interaction;

    // Handle "Create a Ticket" button
    if (customId === 'ticket_create') {
        await interaction.deferReply({ ephemeral: true });
        const user = interaction.user;
        const ticketChannel = await createTicket(guild, user, client);

        if (!ticketChannel) {
            await interaction.editReply({ content: '❌ You already have an open ticket.' });
        } else {
            await interaction.editReply({ content: `✅ Ticket created: <#${ticketChannel.id}>` });
        }
        return true;
    }

    if (!['ticket_close', 'ticket_delete', 'ticket_transcript'].includes(customId)) return false;

    const ticket = await stmts.getTicket(channel.id);
    if (!ticket) {
        await interaction.reply({ content: '❌ This is not a ticket channel.', ephemeral: true });
        return true;
    }

    // Permission check: only staff, owner, or ticket creator
    const isStaff = member.roles.cache.some(r => ['@@ Staff', '@@ Owner', '@@ Co-Owner'].includes(r.name));
    const isCreator = ticket.user_id === member.id;
    if (!isStaff && !isCreator) {
        await interaction.reply({ content: '❌ You do not have permission.', ephemeral: true });
        return true;
    }

    if (customId === 'ticket_transcript') {
        await interaction.deferReply({ ephemeral: true });
        const transcript = await generateTranscript(channel);
        const buffer = Buffer.from(transcript, 'utf-8');
        await interaction.editReply({
            content: '📄 Transcript generated.',
            files: [{ attachment: buffer, name: `transcript-${channel.name}.txt` }],
        });
        return true;
    }

    if (customId === 'ticket_close') {
        await stmts.closeTicket('closed', channel.id);

        // Save transcript to ticket-logs
        const transcript = await generateTranscript(channel);
        const logsRow = await stmts.getState('channel_📂・ticket-logs');
        if (logsRow) {
            const logsChannel = await client.channels.fetch(logsRow).catch(() => null);
            if (logsChannel) {
                const embed = createEmbed({
                    title: '📂 Ticket Closed',
                    description: `**Ticket:** ${channel.name}\n**User:** <@${ticket.user_id}>\n**Closed by:** <@${member.id}>`,
                    color: Colors.WARNING,
                });
                const buffer = Buffer.from(transcript, 'utf-8');
                await logsChannel.send({
                    embeds: [embed],
                    files: [{ attachment: buffer, name: `transcript-${channel.name}.txt` }],
                });
            }
        }

        await logTicket(client, { user: { tag: ticket.username, id: ticket.user_id }, action: 'closed', channelName: channel.name });

        // Delete the channel after a short delay
        const closeEmbed = createEmbed({
            title: '🔒 Ticket Closed',
            description: 'This ticket has been closed. The channel will be deleted in 5 seconds.',
            color: Colors.WARNING,
        });
        await interaction.reply({ embeds: [closeEmbed] });
        setTimeout(() => channel.delete().catch(() => { }), 5000);
        return true;
    }

    if (customId === 'ticket_delete') {
        await stmts.closeTicket('deleted', channel.id);
        await logTicket(client, { user: { tag: ticket.username, id: ticket.user_id }, action: 'deleted', channelName: channel.name });
        await interaction.reply({ content: '🗑️ Deleting ticket...' });
        setTimeout(() => channel.delete().catch(() => { }), 1000);
        return true;
    }

    return false;
}

module.exports = { sendTicketEmbed, createTicket, handleTicketButton, generateTranscript };