feat: dark mode (#177)

* Created base svg renderer

* Improve renderigng

* Added roboto font

* Added ticks calcaulation

* Added chart rendering

* Fixed 2 pixel shifting for y axis

* Moved chart styles in constant

* Replaced go-chart to internal chart

* Added correct dark theme

* Updated .gitignore

* Refactoring

Refactored font embedding

* Fixed corners rendering

* Removed debug code

* Refactoring

* Minimize memory allocaitons

* Moved colours to css variables

* Fixed html

* Color sheme draft

WIP

* Added chart variants

* Added adaptive favicon

* Added query params colors

* Added custom color impoementation

* WIP

* Added configuration to cosmtrek/air

* Added chart caching

* Final updating markup

* Fixed errors rendering

* Cleanup

.air.toml

@@ -0,0 +1,10 @@
+root = "."
+
+[build]
+include_ext = ["go", "css", "svg", "html", "js", "gohtml"]
+stop_on_error = false
+rerun_delay = 0
+
+[misc]
+# Delete tmp directory on exit
+clean_on_exit = true

.editorconfig

@@ -0,0 +1,16 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_size = 4
+indent_style = space
+insert_final_newline = true
+max_line_length = 120
+tab_width = 4
+
+[{*.go,*.go2}]
+indent_style = tab
+
+[*.svg]
+indent_size = 2

.gitignore

@@ -2,3 +2,6 @@ vendor
 bin
 coverage.txt
 dist
+.idea
+.DS_Store
+tmp

controller/chart.go

@@ -0,0 +1,120 @@
+package controller
+
+import (
+	"fmt"
+	"github.com/apex/log"
+	"github.com/caarlos0/httperr"
+	"github.com/caarlos0/starcharts/internal/cache"
+	"github.com/caarlos0/starcharts/internal/chart"
+	"github.com/caarlos0/starcharts/internal/chart/svg"
+	"github.com/caarlos0/starcharts/internal/github"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+)
+
+var stylesMap = map[string]string{
+	"light":    chart.LightStyles,
+	"dark":     chart.DarkStyles,
+	"adaptive": chart.AdaptiveStyles,
+}
+
+// GetRepoChart returns the SVG chart for the given repository.
+//
+// nolint: funlen
+// TODO: refactor.
+func GetRepoChart(gh *github.GitHub, cache *cache.Redis) http.Handler {
+	return httperr.NewF(func(w http.ResponseWriter, r *http.Request) error {
+		params, err := extractSvgChartParams(r)
+		if err != nil {
+			log.WithError(err).Error("failed to extract params")
+			return err
+		}
+
+		cacheKey := chartKey(params)
+		name := fmt.Sprintf("%s/%s", params.Owner, params.Repo)
+		log := log.WithField("repo", name).WithField("variant", params.Variant)
+
+		cachedChart := ""
+		if err = cache.Get(cacheKey, &cachedChart); err == nil {
+			writeSvgHeaders(w)
+			log.Debug("using cached chart")
+			_, err := fmt.Fprint(w, cachedChart)
+			return err
+		}
+
+		defer log.Trace("collect_stars").Stop(nil)
+		repo, err := gh.RepoDetails(r.Context(), name)
+		if err != nil {
+			return httperr.Wrap(err, http.StatusBadRequest)
+		}
+
+		stargazers, err := gh.Stargazers(r.Context(), repo)
+		if err != nil {
+			log.WithError(err).Error("failed to get stars")
+			writeSvgHeaders(w)
+			_, err = w.Write([]byte(errSvg(err)))
+			return err
+		}
+
+		series := chart.Series{
+			StrokeWidth: 2,
+			Color:       params.Line,
+		}
+		for i, star := range stargazers {
+			series.XValues = append(series.XValues, star.StarredAt)
+			series.YValues = append(series.YValues, float64(i))
+		}
+		if len(series.XValues) < 2 {
+			log.Info("not enough results, adding some fake ones")
+			series.XValues = append(series.XValues, time.Now())
+			series.YValues = append(series.YValues, 1)
+		}
+
+		graph := &chart.Chart{
+			Width:      CHART_WIDTH,
+			Height:     CHART_HEIGHT,
+			Styles:     stylesMap[params.Variant],
+			Background: params.Background,
+			XAxis: chart.XAxis{
+				Name:        "Time",
+				Color:       params.Axis,
+				StrokeWidth: 2,
+			},
+			YAxis: chart.YAxis{
+				Name:        "Stargazers",
+				Color:       params.Axis,
+				StrokeWidth: 2,
+			},
+			Series: series,
+		}
+		defer log.Trace("chart").Stop(&err)
+
+		writeSvgHeaders(w)
+
+		cacheBuffer := &strings.Builder{}
+		graph.Render(io.MultiWriter(w, cacheBuffer))
+		err = cache.Put(cacheKey, cacheBuffer.String())
+		if err != nil {
+			log.WithError(err).Error("failed to cache chart")
+		}
+
+		return nil
+	})
+}
+
+func errSvg(err error) string {
+	return svg.SVG().
+		Attr("width", svg.Px(CHART_WIDTH)).
+		Attr("height", svg.Px(CHART_HEIGHT)).
+		ContentFunc(func(writer io.Writer) {
+			svg.Text().
+				Attr("fill", "red").
+				Attr("x", svg.Px(CHART_WIDTH/2)).
+				Attr("y", svg.Px(CHART_HEIGHT/2)).
+				Content(err.Error()).
+				Render(writer)
+		}).
+		String()
+}

controller/helpers.go

@@ -0,0 +1,87 @@
+package controller
+
+import (
+	"fmt"
+	"github.com/gorilla/mux"
+	"net/http"
+	"regexp"
+	"time"
+)
+
+const (
+	base       = "static/templates/base.gohtml"
+	repository = "static/templates/repository.gohtml"
+	index      = "static/templates/index.gohtml"
+)
+
+var colorExpression = regexp.MustCompile("^#([a-fA-F0-9]{6}|[a-fA-F0-9]{3}|[a-fA-F0-9]{8})$")
+
+func extractColor(r *http.Request, name string) (string, error) {
+	color := r.URL.Query().Get(name)
+	if len(color) == 0 {
+		return "", nil
+	}
+
+	if colorExpression.MatchString(color) {
+		return color, nil
+	}
+
+	return "", fmt.Errorf("invalid %s: %s", name, color)
+}
+
+type params struct {
+	Owner      string
+	Repo       string
+	Line       string
+	Background string
+	Axis       string
+	Variant    string
+}
+
+func extractSvgChartParams(r *http.Request) (*params, error) {
+	backgroundColor, err := extractColor(r, "background")
+	if err != nil {
+		return nil, err
+	}
+
+	axisColor, err := extractColor(r, "axis")
+	if err != nil {
+		return nil, err
+	}
+
+	lineColor, err := extractColor(r, "line")
+	if err != nil {
+		return nil, err
+	}
+
+	vars := mux.Vars(r)
+
+	return &params{
+		Owner:      vars["owner"],
+		Repo:       vars["repo"],
+		Background: backgroundColor,
+		Axis:       axisColor,
+		Line:       lineColor,
+		Variant:    r.URL.Query().Get("variant"),
+	}, nil
+}
+
+func writeSvgHeaders(w http.ResponseWriter) {
+	header := w.Header()
+	header.Add("content-type", "image/svg+xml;charset=utf-8")
+	header.Add("cache-control", "public, max-age=86400")
+	header.Add("date", time.Now().Format(time.RFC1123))
+	header.Add("expires", time.Now().Format(time.RFC1123))
+}
+
+func chartKey(params *params) string {
+	return fmt.Sprintf(
+		"%s/%s/[%s][%s][%s][%s]",
+		params.Owner,
+		params.Repo,
+		params.Variant,
+		params.Background,
+		params.Axis,
+		params.Line,
+	)
+}

controller/index.go

@@ -2,28 +2,27 @@ package controller
 
 import (
 	"html/template"
-	"io"
 	"io/fs"
 	"net/http"
 	"strings"
 
 	"github.com/caarlos0/httperr"
 )
 
-func Index(fsys fs.FS, version string) http.Handler {
+func Index(filesystem fs.FS, version string) http.Handler {
+	indexTemplate, err := template.ParseFS(filesystem, base, index)
+	if err != nil {
+		panic(err)
+	}
+
 	return httperr.NewF(func(w http.ResponseWriter, r *http.Request) error {
-		return executeTemplate(fsys, w, map[string]string{"Version": version})
+		return indexTemplate.Execute(w, map[string]string{"Version": version})
 	})
 }
 
-func HandleForm(fsys fs.FS) http.HandlerFunc {
+func HandleForm() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		repo := strings.TrimPrefix(r.FormValue("repository"), "https://github.com/")
 		http.Redirect(w, r, repo, http.StatusSeeOther)
 	}
 }
-
-func executeTemplate(fsys fs.FS, w io.Writer, data interface{}) error {
-	return template.Must(template.ParseFS(fsys, "static/templates/index.html")).
-		Execute(w, data)
-}