Изменены пути название файлы main.js -> chart.js

chart/chart.js

@@ -0,0 +1,112 @@
+const ChartJSImage = require('chart.js-image');
+const pool = require('../shared/database/src/postgresql.js');
+const fs = require('fs');
+const axios = require('axios');
+const logger = require('../shared/logger/src/main.js')
+
+/**
+ * Graph generation
+ * @param {String} from_currency - The currency that is being converted
+ * @param {String} conv_currency - The currency to be converted into
+ * @param {String} start_date - Start date of the period
+ * @param {String} end_date - End date of the period
+ * @returns {Promise<Error|string>}
+ */
+async function gen_chart(from_currency, conv_currency, start_date, end_date) {
+    const data = await pool.query('SELECT date, rate FROM currency WHERE ' +
+        '(date BETWEEN $3 AND $4) AND from_currency = $1 AND conv_currency = $2 ORDER BY date ', [
+        from_currency.toUpperCase(),
+        conv_currency.toUpperCase(),
+        start_date,
+        end_date
+    ]);
+
+    if (!data['rows'][0]) return 'Missing data';
+
+    const date = [];
+    const rate = [];
+
+    for (let i = 0; i < data.rows.length; i++) {
+        date.push(data.rows[i].date.toLocaleDateString());
+        rate.push(data.rows[i].rate);
+    }
+
+    const chart = ChartJSImage().chart({
+        type: 'line',
+        options: {
+            title: {
+                  display: true,
+                  text: `${from_currency} / ${conv_currency}`,
+              },
+            scales: [
+                {
+                    yAxes: [
+                        {
+                            ticks: {
+                                beginAtZero: false,
+                            }
+                        }
+                    ]
+                }
+            ]
+        },
+        data: {
+            labels: date,
+            datasets: [
+                {
+                    borderColor: rate[0] < rate[rate.length-1] ? 'rgb(24, 218, 39)' : 'rgb(243, 85, 50)',
+                    backgroundColor:  rate[0] < rate[rate.length-1] ? 'rgb(36, 175, 47)' : 'rgb(218, 56, 24)',
+                    data: rate,
+                    borderWidth: 2,
+                },
+            ],
+        },
+        scales: {
+           xAxes: [
+               {
+                   scaleLabel: {
+                       display: true,
+                       labelString: 'Day'
+                   },
+               },
+           ],
+            yAxes: [
+                {
+                    stacked: false,
+                    scaleLabel: {
+                        display: true,
+                        labelString: 'Rate'
+                    },
+                },
+            ],
+        },
+    }).width(1000).height(1000);
+
+    logger.debug(chart.toURL());
+
+    return chart.toURL();
+}
+
+
+/**
+ * Saving a graph to a file
+ * @param {String} url  - URL (or Buffer) to the chart
+ * @param {String} filename - filename
+ */
+function save_chart(url, filename) {
+    if (!fs.existsSync('../charts')) fs.mkdirSync('../charts');
+    if (!url.startsWith('https://')) throw new Error('The passed parameter is not a URL');
+
+    logger.info(`The schedule has been saved. The path of the graph 'chart/${filename}'`);
+    axios({url, responseType: 'stream',}).then(
+        response =>
+            new Promise((resolve, reject) => {
+                response.data
+                    .pipe(fs.createWriteStream(`../charts/${filename}`))
+                    .on('finish', () => resolve())
+                    .on('error', e => reject(e));
+            })
+    );
+}
+
+module.exports = { gen_chart, save_chart }