const { SlashCommandBuilder, EmbedBuilder, AttachmentBuilder } = require('discord.js');
const axios = require('axios').default;
const { HOUSEHOLD_IDS } = require('../../core/constants.js');

const CHART_COLORS = {
    [HOUSEHOLD_IDS.MINZ]: '#4e79a7',
    [HOUSEHOLD_IDS.MIFFY]: '#f28e2b',
};
const DISPLAY_NAMES = {
    [HOUSEHOLD_IDS.MINZ]: 'Minz',
    [HOUSEHOLD_IDS.MIFFY]: 'Miffy',
};

module.exports = {
    category: 'utility',
    global: true,
    data: new SlashCommandBuilder()
        .setName('budget')
        .setDescription('The thing')
        .addSubcommand(subcommand =>
            subcommand
                .setName('set')
                .setDescription('Set weekly budget')
                .addIntegerOption(option =>
                    option.setName('amount')
                        .setRequired(true)
                        .setDescription('Amount as int'))
                .addBooleanOption(option =>
                    option.setName('override')
                        .setRequired(false)
                        .setDescription('Override budget of current period'))
        )
        .addSubcommand(subcommand =>
            subcommand
                .setName('view')
                .setDescription('View your grocery spendings for the current or previous week')
                .addUserOption(option =>
                    option.setName('user')
                        .setRequired(false)
                        .setDescription('User to view budget for'))
                .addBooleanOption(option =>
                    option
                        .setName('lastweek')
                        .setDescription('Show spendings from the previous budget cycle instead of the current one')
                        .setRequired(false)
                )
        )
        .addSubcommand(subcommand =>
            subcommand
                .setName('stats')
                .setDescription('View detailed spending and savings statistics')
                .addUserOption(option =>
                    option.setName('user')
                        .setRequired(false)
                        .setDescription('User to view stats for'))
        )
        .addSubcommand(subcommand =>
            subcommand
                .setName('chart')
                .setDescription('Render a bar chart comparing Minz and Miffy spendings over time')
                .addIntegerOption(option =>
                    option.setName('weeks')
                        .setRequired(false)
                        .setDescription('Number of recent weeks to include (default 8)'))
        ),
    async execute(interaction) {
        let db = await interaction.client.localDB;
        let targetUser = interaction.options.getUser('user') ?? interaction.user;
        let discordId = interaction.member.id;
        let allowed = [HOUSEHOLD_IDS.MIFFY, HOUSEHOLD_IDS.MINZ].includes(discordId);
        if (!allowed) {
            await interaction.reply('This command may only be invoked by Miffy!');
            return;
        }
        switch (interaction.options.getSubcommand()) {
            case 'set':
                let override = interaction.options.getBoolean('override') ?? false;
                let budget = interaction.options.get('amount').value;
                db.prepare(`INSERT OR REPLACE INTO bot_config (id, weekly_budget) VALUES (1, ?)`).run(budget);
                let overrideApplied = true;
                if (override) {
                    const result = db.prepare(`
                        UPDATE weekly_budgets
                        SET budget_amount = ?
                        WHERE id = (
                            SELECT id FROM weekly_budgets
                            WHERE date('now', 'localtime') BETWEEN start_date AND end_date
                            ORDER BY id DESC
                            LIMIT 1
                        )`).run(budget);
                    overrideApplied = result.changes > 0;
                }
                const overrideNote = override && !overrideApplied ? " (no active budget period to override this week)" : "";
                await interaction.reply(`Budget set for ${targetUser.username} to ${Number(budget).toFixed(2)}.${overrideNote}`);
                break;
            case 'view':
                const lastWeek = interaction.options.getBoolean('lastweek') ?? false;
                const currentBudget = db.prepare(`
                    SELECT id, budget_amount, exchange_rate, start_date, end_date 
                    FROM weekly_budgets 
                    WHERE ${lastWeek ? "end_date < date('now', 'localtime')" : "date('now', 'localtime') BETWEEN start_date AND end_date"}
                    ORDER BY start_date DESC, created_at DESC
                    LIMIT 1
                `).get();

                if (!currentBudget) {
                    await interaction.reply("No budget period found.");
                    return;
                }

                const userSpendings = db.prepare(`
                    SELECT amount, message_raw 
                    FROM grocery_spendings 
                    WHERE budget_id = ? AND discord_id = ?
                `).all(currentBudget.id, targetUser.id);

                const totalSpentEur = userSpendings.reduce((acc, s) => {
                    return acc + s.amount;
                }, 0);

                const remainingEur = currentBudget.budget_amount - totalSpentEur;
                const remainingSek = remainingEur * currentBudget.exchange_rate;

                const todayTimestamp = Math.floor(Date.now() / 1000);
                const endTimestamp = Math.floor(new Date(`${currentBudget.end_date}T23:59:59`).getTime() / 1000);

                const budgetEmbed = new EmbedBuilder()
                    .setColor(remainingEur > 0 ? 0x00ff00 : 0xff0000)
                    .setTitle(`${targetUser.globalName ?? targetUser.username} Budget as of <t:${todayTimestamp}:F>`)
                    .setDescription(`Period: \`${currentBudget.start_date}\` to \`${currentBudget.end_date}\`\nReset <t:${endTimestamp}:R>`)
                    .addFields(
                        { name: 'Spent', value: `${totalSpentEur.toFixed(2)} €\n${(totalSpentEur * currentBudget.exchange_rate).toFixed(2)} kr`, inline: true },
                        { name: 'Remaining', value: `${remainingEur.toFixed(2)} €\n${remainingSek.toFixed(2)} kr`, inline: true },
                    )
                    .setFooter({ text: `Exchange rate this week: 1 € = ${currentBudget.exchange_rate.toFixed(2)} kr` })
                    .setTimestamp();

                await interaction.reply({ embeds: [budgetEmbed] });
                break
            case 'stats':
                const allBudgets = db.prepare(`
                    SELECT id, budget_amount, exchange_rate, start_date, end_date
                    FROM weekly_budgets
                    ORDER BY start_date DESC
                    LIMIT 4
                `).all().reverse();

                let statsDescription = "";
                let cumulativeSavingsEur = 0;

                for (const budgetPeriod of allBudgets) {
                    const periodSpendings = db.prepare(`
                        SELECT amount 
                        FROM grocery_spendings 
                        WHERE budget_id = ? AND discord_id = ?
                    `).all(budgetPeriod.id, targetUser.id);

                    const totalSpentInPeriodEur = periodSpendings.reduce((acc, s) => acc + s.amount, 0);
                    const savedInPeriodEur = Number(budgetPeriod.budget_amount) - Number(totalSpentInPeriodEur);
                    cumulativeSavingsEur += savedInPeriodEur;

                    statsDescription += `**Period: ${budgetPeriod.start_date} - ${budgetPeriod.end_date}**\n`;
                    statsDescription += `Budget: ${budgetPeriod.budget_amount.toFixed(2)}€\n`;
                    statsDescription += `Spent: ${totalSpentInPeriodEur.toFixed(2)}€ (${(totalSpentInPeriodEur * budgetPeriod.exchange_rate).toFixed(2)} kr)\n`;
                    statsDescription += `Saved: ${savedInPeriodEur.toFixed(2)}€ (${(savedInPeriodEur * budgetPeriod.exchange_rate).toFixed(2)} kr)\n`;
                    statsDescription += `Cumulative: ${cumulativeSavingsEur.toFixed(2)}€\n\n`;
                }

                if (allBudgets.length === 0) {
                    statsDescription = "No budget periods on record.";
                }

                const statsEmbed = new EmbedBuilder()
                    .setColor(0x0099ff)
                    .setTitle(`${targetUser.globalName ?? targetUser.username}'s Budget Statistics`)
                    .setDescription(statsDescription)
                    .setTimestamp();

                await interaction.reply({ embeds: [statsEmbed] });
                break;
            case 'chart': {
                const weeks = Math.min(Math.max(interaction.options.getInteger('weeks') ?? 8, 1), 52);

                const chartPeriods = db.prepare(`
                    SELECT id, start_date, end_date
                    FROM weekly_budgets
                    ORDER BY start_date DESC
                    LIMIT ?
                `).all(weeks).reverse();

                if (chartPeriods.length === 0) {
                    await interaction.reply("No budget periods on record.");
                    return;
                }

                await interaction.deferReply();

                const spentByUserAndPeriod = db.prepare(`
                    SELECT COALESCE(SUM(amount), 0) as total
                    FROM grocery_spendings
                    WHERE budget_id = ? AND discord_id = ?
                `);

                const labels = chartPeriods.map(period => period.start_date.slice(5));
                const datasets = [HOUSEHOLD_IDS.MINZ, HOUSEHOLD_IDS.MIFFY].map(userId => ({
                    label: DISPLAY_NAMES[userId],
                    backgroundColor: CHART_COLORS[userId],
                    data: chartPeriods.map(period => spentByUserAndPeriod.get(period.id, userId).total),
                }));

                const chartConfig = {
                    type: 'bar',
                    data: { labels, datasets },
                    options: {
                        title: { display: true, text: 'Weekly Grocery Spending (€)' },
                        scales: {
                            yAxes: [{ ticks: { beginAtZero: true }, scaleLabel: { display: true, labelString: '€' } }],
                        },
                    },
                };

                try {
                    const response = await axios.post('https://quickchart.io/chart', {
                        chart: chartConfig,
                        width: 800,
                        height: 400,
                        backgroundColor: 'white',
                    }, { responseType: 'arraybuffer' });

                    const attachment = new AttachmentBuilder(Buffer.from(response.data), { name: 'budget-chart.png' });
                    const chartEmbed = new EmbedBuilder()
                        .setColor(0x0099ff)
                        .setTitle('Weekly Grocery Spending')
                        .setDescription(`Last ${chartPeriods.length} week(s): \`${chartPeriods[0].start_date}\` to \`${chartPeriods[chartPeriods.length - 1].end_date}\``)
                        .setImage('attachment://budget-chart.png')
                        .setTimestamp();

                    await interaction.editReply({ embeds: [chartEmbed], files: [attachment] });
                } catch (error) {
                    console.error('[budget chart] Failed to render chart:', error);
                    await interaction.editReply("Failed to render the chart, sorry!");
                }
                break;
            }
            default:
                await interaction.reply(`Sub mismatch. Switching on ${interaction.options.getSubcommand()}`);
                break;
        }
    },
};