Add budget spending chart command

commands/receipts/receiptCommands.js

@@ -1,6 +1,16 @@
-const { SlashCommandBuilder, EmbedBuilder } = require('discord.js');
+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,
@@ -43,6 +53,15 @@ module.exports = {
                     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;
@@ -159,6 +178,70 @@ module.exports = {
 
                 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;