Merge pull request #22 from nao1215/piechart

Introduce pie chart (mermaid)

README.md

@@ -32,7 +32,8 @@ Additionally, complex code that increases the complexity of the library, such as
 - [x] Plain text
 - [x] Details 
 - [x] Alerts; NOTE, TIP, IMPORTANT, CAUTION, WARNING
-- [x] mermaid (only support sequence diagram)
+- [x] mermaid sequence diagram
+- [x] mermaid pie chart
 
 ### Features not in Markdown syntax
 - Generate badges; RedBadge(), YellowBadge(), GreenBadge().
@@ -182,7 +183,7 @@ go generate ./...
 This markdown is generated by `go generate`
 ````
 
-### Generate alerts
+### Alerts syntax
 The markdown package can create alerts. Alerts are useful for displaying important information in Markdown. This syntax is supported by GitHub.
 [Code example:](./doc/alert/main.go)
 ```go
@@ -231,7 +232,7 @@ Your alert will look like this;
 > [!CAUTION]  
 > This is caution
 
-### Generate status badge
+### Status badge syntax
 The markdown package can create red, yellow, and green status badges.
 [Code example:](./doc/badge/main.go)
 ```go
@@ -256,8 +257,7 @@ Your badge will look like this;
 ![Badge](https://img.shields.io/badge/yellow_badge-yellow)
 ![Badge](https://img.shields.io/badge/green_badge-green)
 
-### Generate mermaid sequence diagram
-Generate mermaid in markdown. You can generate mermaid using go generate. Please define code to generate Mermaid first. Then, run "go generate ./..." to generate it.
+### Mermaid sequence diagram syntax
 
 ```go
 package main
@@ -272,7 +272,7 @@ import (
 //go:generate go run main.go
 
 func main() {
-	diagram := sequence.NewDiagram(os.Stdout).
+	diagram := sequence.NewDiagram(io.Discard).
 		Participant("Sophia").
 		Participant("David").
 		Participant("Subaru").
@@ -346,7 +346,70 @@ sequenceDiagram
     David-->>Sophia: wake up, wake up
 ```
 
+### Pie chart syntax
 
+```go
+package main
+
+import (
+	"io"
+	"os"
+
+	"github.com/nao1215/markdown"
+	"github.com/nao1215/markdown/mermaid/piechart"
+)
+
+//go:generate go run main.go
+
+func main() {
+	f, err := os.Create("generated.md")
+	if err != nil {
+		panic(err)
+	}
+
+	chart := piechart.NewPieChart(
+		io.Discard,
+		piechart.WithTitle("mermaid pie chart builder"),
+		piechart.WithShowData(true),
+	).
+		LabelAndIntValue("A", 10).
+		LabelAndFloatValue("B", 20.1).
+		LabelAndIntValue("C", 30).
+		String()
+
+	err = markdown.NewMarkdown(f).
+		H2("Pie Chart").
+		CodeBlocks(markdown.SyntaxHighlightMermaid, chart).
+		Build()
+
+	if err != nil {
+		panic(err)
+	}
+}
+```
+
+Plain text output: [markdown is here](./doc/piechart/generated.md)
+````
+## Pie Chart
+```mermaid
+%%{init: {"pie": {"textPosition": 0.75}, "themeVariables": {"pieOuterStrokeWidth": "5px"}} }%%
+pie showData
+    title mermaid pie chart builder
+    "A" : 10
+    "B" : 20.100000
+    "C" : 30
+```
+````
+
+Mermaid output:
+```mermaid
+%%{init: {"pie": {"textPosition": 0.75}, "themeVariables": {"pieOuterStrokeWidth": "5px"}} }%%
+pie showData
+    title mermaid pie chart builder
+    "A" : 10
+    "B" : 20.100000
+    "C" : 30
+```
 
 ## Creating an index for a directory full of markdown files
 The markdown package can create an index for Markdown files within the specified directory. This feature was added to generate indexes for Markdown documents produced by [nao1215/spectest](https://github.com/nao1215/spectest).

doc/piechart/generated.md

@@ -0,0 +1,9 @@
+## Pie Chart
+```mermaid
+%%{init: {"pie": {"textPosition": 0.75}, "themeVariables": {"pieOuterStrokeWidth": "5px"}} }%%
+pie showData
+    title mermaid pie chart builder
+    "A" : 10
+    "B" : 20.100000
+    "C" : 30
+```

doc/piechart/main.go

@@ -0,0 +1,40 @@
+//go:build linux || darwin
+
+// Package main is generating mermaid sequence diagram.
+package main
+
+import (
+	"io"
+	"os"
+
+	"github.com/nao1215/markdown"
+	"github.com/nao1215/markdown/mermaid/piechart"
+)
+
+//go:generate go run main.go
+
+func main() {
+	f, err := os.Create("generated.md")
+	if err != nil {
+		panic(err)
+	}
+
+	chart := piechart.NewPieChart(
+		io.Discard,
+		piechart.WithTitle("mermaid pie chart builder"),
+		piechart.WithShowData(true),
+	).
+		LabelAndIntValue("A", 10).
+		LabelAndFloatValue("B", 20.1).
+		LabelAndIntValue("C", 30).
+		String()
+
+	err = markdown.NewMarkdown(f).
+		H2("Pie Chart").
+		CodeBlocks(markdown.SyntaxHighlightMermaid, chart).
+		Build()
+
+	if err != nil {
+		panic(err)
+	}
+}

doc/sequence/main.go

@@ -4,6 +4,7 @@
 package main
 
 import (
+	"io"
 	"os"
 
 	"github.com/nao1215/markdown"
@@ -18,7 +19,7 @@ func main() {
 		panic(err)
 	}
 
-	diagram := sequence.NewDiagram(os.Stdout).
+	diagram := sequence.NewDiagram(io.Discard).
 		Participant("Sophia").
 		Participant("David").
 		Participant("Subaru").

mermaid/piechart/config.go

@@ -0,0 +1,60 @@
+package piechart
+
+// config is a pie chart configuration.
+type config struct {
+	// The axial position of the pie slice labels,
+	// from 0.0 at the center to 1.0 at the outside edge of the circle.
+	textPosition float64
+	// showData is a flag to show the data in the pie chart.
+	showData bool
+	// title is the title of the pie chart.
+	title string
+}
+
+// newConfig returns a new Config with default values.
+func newConfig() *config {
+	return &config{
+		textPosition: defaultTextPosition,
+	}
+}
+
+const (
+	// defaultTextPosition is the default axial position of the pie slice labels.
+	defaultTextPosition float64 = 0.75
+	// minTextPosition is the minimum axial position of the pie slice labels.
+	minTextPosition float64 = 0.0
+	// maxTextPosition is the maximum axial position of the pie slice labels.
+	maxTextPosition float64 = 1.0
+	// noTitle is a constant for no title.
+	noTitle string = ""
+)
+
+// Option sets the options for the PieChart struct.
+type Option func(*config)
+
+// WithTextPosition sets the axial position of the pie slice labels.
+// The axial position of the pie slice labels, from 0.0 at the center
+// to 1.0 at the outside edge of the circle.
+// If pos is less than 0.0 or greater than 1.0, it will be set to the default value (0.75)
+func WithTextPosition(pos float64) Option {
+	return func(c *config) {
+		if pos < minTextPosition || pos > maxTextPosition {
+			pos = defaultTextPosition
+		}
+		c.textPosition = pos
+	}
+}
+
+// WithShowData sets the showData configuration.
+func WithShowData(showData bool) Option {
+	return func(c *config) {
+		c.showData = showData
+	}
+}
+
+// WithTitle sets the title configuration.
+func WithTitle(title string) Option {
+	return func(c *config) {
+		c.title = title
+	}
+}

mermaid/piechart/pie_chart.go

@@ -0,0 +1,93 @@
+// Package piechart is mermaid pie chart builder.
+package piechart
+
+import (
+	"fmt"
+	"io"
+	"runtime"
+	"strings"
+)
+
+// PieChart is a pie chart builder.
+type PieChart struct {
+	// body is pie chart body.
+	body []string
+	// dest is output destination for pie chart body.
+	dest io.Writer
+	// err manages errors that occur in all parts of the pie chart building.
+	err error
+	// config is the configuration for the pie chart.
+	config *config
+}
+
+// NewPieChart returns a new PieChart.
+func NewPieChart(w io.Writer, opts ...Option) *PieChart {
+	c := newConfig()
+
+	for _, opt := range opts {
+		opt(c)
+	}
+
+	lines := []string{}
+	lines = append(
+		lines,
+		fmt.Sprintf(
+			"%%%%{init: {\"pie\": {\"textPosition\": %.2f}, \"themeVariables\": {\"pieOuterStrokeWidth\": \"5px\"}} }%%%%",
+			c.textPosition,
+		))
+
+	baseLine := "pie"
+	if c.showData {
+		baseLine += " showData"
+	}
+
+	if c.title == noTitle {
+		lines = append(lines, baseLine)
+	} else {
+		lines = append(lines, baseLine)
+		lines = append(lines, fmt.Sprintf("    title %s", c.title))
+	}
+
+	return &PieChart{
+		body:   lines,
+		dest:   w,
+		config: c,
+	}
+}
+
+// String returns the pie chart body.
+func (p *PieChart) String() string {
+	return strings.Join(p.body, lineFeed())
+}
+
+// Build writes the pie chart body to the output destination.
+func (p *PieChart) Build() error {
+	if _, err := fmt.Fprint(p.dest, p.String()); err != nil {
+		if p.err != nil {
+			return fmt.Errorf("failed to write: %w: %s", err, p.err.Error()) //nolint:wrapcheck
+		}
+		return fmt.Errorf("failed to write: %w", err)
+	}
+	return nil
+}
+
+// LabelAndIntValue adds a label and value to the pie chart.
+func (p *PieChart) LabelAndIntValue(label string, value uint64) *PieChart {
+	p.body = append(p.body, fmt.Sprintf("    \"%s\" : %d", label, value))
+	return p
+}
+
+// LabelAndFloatValue adds a label and value to the pie chart.
+// The value is formatted with a precision of 6 digits after the decimal point.
+func (p *PieChart) LabelAndFloatValue(label string, value float64) *PieChart {
+	p.body = append(p.body, fmt.Sprintf("    \"%s\" : %f", label, value))
+	return p
+}
+
+// lineFeed return line feed for current OS.
+func lineFeed() string {
+	if runtime.GOOS == "windows" {
+		return "\r\n"
+	}
+	return "\n"
+}