chore: initial commit

.github/workflows/main.yml

@@ -0,0 +1,22 @@
+name: CI
+
+on: push
+
+concurrency:
+  group: ${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: Run tests
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+      - name: Set up Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: "1.22"
+      - name: Run test script
+        run: |
+          chmod +x ./scripts/test.sh && ./scripts/test.sh

.gitignore

@@ -0,0 +1,27 @@
+# If you prefer the allow list template instead of the deny list, see community template:
+# https://github.com/github/gitignore/blob/main/community/Golang/Go.AllowList.gitignore
+#
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
+
+# Go workspace file
+go.work
+go.work.sum
+
+# env file
+.env
+
+.idea

go.mod

@@ -0,0 +1,17 @@
+module github.com/nejdetkadir/statemachine
+
+go 1.22.2
+
+require (
+	github.com/jedib0t/go-pretty/v6 v6.5.9
+	github.com/stretchr/testify v1.8.4
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/mattn/go-runewidth v0.0.15 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/rivo/uniseg v0.2.0 // indirect
+	golang.org/x/sys v0.17.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -0,0 +1,18 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/jedib0t/go-pretty/v6 v6.5.9 h1:ACteMBRrrmm1gMsXe9PSTOClQ63IXDUt03H5U+UV8OU=
+github.com/jedib0t/go-pretty/v6 v6.5.9/go.mod h1:zbn98qrYlh95FIhwwsbIip0LYpwSG8SUOScs+v9/t0E=
+github.com/mattn/go-runewidth v0.0.15 h1:UNAjwbU9l54TA3KzvqLGxwWjHmMgBUVhBiTjelZgg3U=
+github.com/mattn/go-runewidth v0.0.15/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/rivo/uniseg v0.2.0 h1:S1pD9weZBuJdFmowNwbpi7BJ8TNftyUImj/0WQi72jY=
+github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+golang.org/x/sys v0.17.0 h1:25cE3gD+tdBA7lp7QfhuV+rJiE9YXTcS3VG1SqssI/Y=
+golang.org/x/sys v0.17.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

scripts/test.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+output=$(go test ./...)
+result=$?
+
+if [ $result -ne 0 ]; then
+    echo "Some tests failed:"
+    echo "$output"
+    exit 1
+else
+    go test ./... -v
+    exit 0
+fi

statemachine.go

@@ -0,0 +1,178 @@
+package statemachine
+
+import (
+	"errors"
+	"fmt"
+	"github.com/jedib0t/go-pretty/v6/table"
+	"os"
+	"slices"
+)
+
+type (
+	Context struct {
+		states       []string
+		initialState string
+		currentState string
+		events       []Event
+		beforeAll    func(event string, from string, to string)
+		afterAll     func(event string, from string, to string)
+	}
+	Event struct {
+		name     string
+		to       string
+		from     []string
+		before   func()
+		after    func()
+		validate func(from string, to string) error
+	}
+	StateMachine interface {
+		CurrentState() string
+		Fire(event string) error
+		RegisterEvent(event Event) error
+		RegisterEvents(events []Event) error
+		BeforeAll(before func(event string, from string, to string))
+		AfterAll(after func(event string, from string, to string))
+		RenderGraph()
+		Context() *Context
+		SetCurrentState(state string) error
+	}
+)
+
+func New(states []string, initialState string) (StateMachine, error) {
+	if slices.Contains(states, initialState) == false {
+		return nil, errors.New("initial state must be one of the states")
+	}
+
+	return &Context{
+		states:       states,
+		initialState: initialState,
+		currentState: initialState,
+	}, nil
+}
+
+func (c *Context) CurrentState() string {
+	return c.currentState
+}
+
+func (c *Context) Context() *Context {
+	return c
+}
+
+func (c *Context) RegisterEvent(event Event) error {
+	if slices.Contains(c.states, event.to) == false {
+		return errors.New(fmt.Sprintf("to state must be one of: %v", c.states))
+	}
+
+	if slices.ContainsFunc(event.from, func(s string) bool {
+		return slices.Contains(c.states, s) == false
+	}) {
+		return errors.New(fmt.Sprintf("from states must be one of: %v", c.states))
+	}
+
+	if slices.Contains(event.from, event.to) {
+		return errors.New("from and to states cannot be the same")
+	}
+
+	if slices.ContainsFunc(c.events, func(e Event) bool {
+		return e.name == event.name
+	}) {
+		return errors.New("event name must be unique")
+	}
+
+	c.events = append(c.events, event)
+
+	return nil
+}
+
+func (c *Context) RegisterEvents(events []Event) error {
+	var err error
+
+	for _, e := range events {
+		err = c.RegisterEvent(e)
+	}
+
+	if err != nil {
+		c.events = []Event{}
+
+		return err
+	}
+
+	return nil
+}
+
+func (c *Context) BeforeAll(before func(event string, from string, to string)) {
+	c.beforeAll = before
+}
+
+func (c *Context) AfterAll(after func(event string, from string, to string)) {
+	c.afterAll = after
+}
+
+func (c *Context) RenderGraph() {
+	t := table.NewWriter()
+	t.SetOutputMirror(os.Stdout)
+	t.AppendHeader(table.Row{"Event", "From", "To"})
+
+	for _, e := range c.events {
+		t.AppendRow([]interface{}{e.name, e.from, e.to})
+	}
+
+	t.Render()
+}
+
+func (c *Context) Fire(event string) error {
+	var currentEvent *Event
+
+	for _, e := range c.events {
+		if e.name == event {
+			currentEvent = &e
+			break
+		}
+	}
+
+	if currentEvent == nil {
+		return errors.New(fmt.Sprintf("%s event is not registered", event))
+	}
+
+	if slices.Contains(currentEvent.from, c.currentState) == false {
+		return errors.New(fmt.Sprintf("cannot fire the %s event from the %s state", currentEvent.name, c.currentState))
+	}
+
+	if c.beforeAll != nil {
+		c.beforeAll(currentEvent.name, c.currentState, currentEvent.to)
+	}
+
+	if currentEvent.before != nil {
+		currentEvent.before()
+	}
+
+	if currentEvent.validate != nil {
+		err := currentEvent.validate(c.currentState, currentEvent.to)
+
+		if err != nil {
+			return err
+		}
+	}
+
+	c.currentState = currentEvent.to
+
+	if currentEvent.after != nil {
+		currentEvent.after()
+	}
+
+	if c.afterAll != nil {
+		c.afterAll(currentEvent.name, c.currentState, currentEvent.to)
+	}
+
+	return nil
+}
+
+func (c *Context) SetCurrentState(state string) error {
+	if !slices.Contains(c.states, state) {
+		return errors.New(fmt.Sprintf("state must be one of: %v", c.states))
+	}
+
+	c.currentState = state
+
+	return nil
+}