core/graph.go

// Copyright (c) 2024 Zeni Kim <zenik@smarteching.com>
// Use of this source code is governed by MIT-style
// license that can be found in the LICENSE file.

package core

import (
	"fmt"
	"net/http"
	"strconv"
	"strings"

	"git.smarteching.com/zeni/go-chart/v2"
	"git.smarteching.com/zeni/go-charts/v2"
	"github.com/julienschmidt/httprouter"
)

func Graph(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {

	// $_GET values

	service := ps.ByName("graph")

	if service != "" {

		//serv := strings.TrimPrefix(service, "/")
		serv := strings.Split(service, "/")

		switch serv[1] {

		case "graph":

			kindg := serv[2]

			if kindg != "" {

				switch kindg {
				// case graph pie
				case "pie":

					queryValues := r.URL.Query()
					labels := strings.Split(queryValues.Get("l"), "|")
					values := strings.Split(queryValues.Get("v"), "|")

					qtyl := len(labels)
					qtyv := len(values)

					// check qty and equal values from url
					if qtyl < 2 {
						fmt.Fprintf(w, "Missing captions in pie")
						return
					}
					if qtyv != qtyl {
						fmt.Fprintf(w, "Labels and values mismatch")
						return
					}

					var cvalues []chart.Value
					var row chart.Value
					// fill values
					for index, line := range labels {
						valuefloat, _ := strconv.ParseFloat(values[index], 64)
						row.Value = valuefloat
						row.Label = line
						cvalues = append(cvalues, row)
					}

					pie := chart.PieChart{
						Width:  512,
						Height: 512,
						Values: cvalues,
					}
					w.Header().Set("Content-Type", "image/png")
					err := pie.Render(chart.PNG, w)
					if err != nil {
						fmt.Printf("Error rendering pie chart: %v\n", err)
					}

				// case graph bar
				case "bar":

					queryValues := r.URL.Query()
					labels := strings.Split(queryValues.Get("l"), "|")
					values := strings.Split(queryValues.Get("v"), "|")

					qtyl := len(labels)
					qtyv := len(values)

					// check qty and equal values from url
					if qtyl < 2 {
						fmt.Fprintf(w, "Missing captions in bar")
						return
					}
					if qtyv != qtyl {
						fmt.Fprintf(w, "Labels and values mismatch")
						return
					}

					var cvalues []chart.Value
					var row chart.Value
					// fill values
					for index, line := range labels {
						valuefloat, _ := strconv.ParseFloat(values[index], 64)
						row.Value = valuefloat
						row.Label = line
						cvalues = append(cvalues, row)
					}

					bar := chart.BarChart{
						Height:   512,
						BarWidth: 50,
						Bars:     cvalues,
					}
					w.Header().Set("Content-Type", "image/png")
					err := bar.Render(chart.PNG, w)
					if err != nil {
						fmt.Printf("Error rendering pie chart: %v\n", err)
					}

				// case multiple graph bar
				case "mbar":

					queryValues := r.URL.Query()
					labels := strings.Split(queryValues.Get("l"), "|")
					values := strings.Split(queryValues.Get("v"), "|")
					options := strings.Split(queryValues.Get("o"), "|")

					qtyl := len(labels)
					qtyv := len(values)
					qtyo := len(options)

					// check qty and equal values from url
					if qtyl < 2 {
						fmt.Fprintf(w, "Missing captions in bar")
						return
					}
					if qtyv < 2 {
						fmt.Fprintf(w, "Missing values in bar")
						return
					}
					if qtyo < 2 {
						fmt.Fprintf(w, "Missing options in bar")
						return
					}

					valuest := [][]float64{
						{
							2.0,
							4.9,
							7.0,
							23.2,
							25.6,
							76.7,
							135.6,
							162.2,
							32.6,
						},
						{
							2.6,
							5.9,
							9.0,
							26.4,
							28.7,
							70.7,
							175.6,
							182.2,
							48.7,
						},
					}
					p, err := charts.BarRender(
						valuest,
						charts.XAxisDataOptionFunc([]string{
							"Apr",
							"May",
							"Jun",
							"Jul",
							"Aug",
							"Sep",
							"Oct",
							"Nov",
							"Dec",
						}),
						charts.LegendLabelsOptionFunc(labels, charts.PositionRight),
					)
					if err != nil {
						panic(err)
					}

					buf, err := p.Bytes()

					w.Header().Set("Content-Type", "image/png")
					w.Write(buf)
					if err != nil {
						fmt.Printf("Error rendering pie chart: %v\n", err)
					}

				default:
					fmt.Fprintf(w, "Unknown graph %s!\n", kindg)
				}

			} else {
				fmt.Fprintf(w, "Kind graph not exists")
			}
			//

		default:

			fmt.Fprintf(w, "Unknown option in core service %s!\n", ps.ByName("serv"))

		}
		fmt.Fprintf(w, "Service %s!\n", serv)

	} else {

		fmt.Fprintf(w, "Unknown core service %s!\n", ps.ByName("graph"))
	}

}