refactor: Refactor command definitions

Makefile

@@ -1,6 +1,6 @@
-EXECUTABLE := microgit
+EXECUTABLE := mgit
 
 build:
-	go build -o $(EXECUTABLE) cmd/cmd.go
+	go build -o $(EXECUTABLE) main.go
 install: build
 	sudo mv $(EXECUTABLE) /usr/local/bin/

cmd/abstract.go

@@ -0,0 +1,14 @@
+package cmd
+
+import (
+	"github.com/akamensky/argparse"
+)
+
+type ICommand interface {
+	Register(parser *argparse.Parser)
+	Handle() bool
+}
+
+type CommandMeta struct {
+	Command *argparse.Command
+}

cmd/cat.go

@@ -0,0 +1,66 @@
+package cmd
+
+import (
+	"fmt"
+	"strconv"
+
+	"micro-git/object"
+
+	"github.com/akamensky/argparse"
+)
+
+type CatCommand struct {
+	CommandMeta
+	fileInput            *string
+	shouldShowObjectType *bool
+	shouldShowSize       *bool
+}
+
+func (c *CatCommand) Register(p *argparse.Parser) {
+	c.Command = p.NewCommand("cat-file", "Provide content or type and size information for repository objects")
+	c.fileInput = c.Command.StringPositional(&argparse.Options{
+		Required: true,
+		Help:     "The name of the object to show",
+	})
+	c.shouldShowObjectType = c.Command.Flag("t", "type", &argparse.Options{
+		Default: false,
+		Help:    "Instead of the content, show the object type",
+	})
+	c.shouldShowSize = c.Command.Flag("s", "size", &argparse.Options{
+		Default: false,
+		Help:    "Instead of the content, show the object size",
+	})
+}
+
+func (c *CatCommand) Handle() bool {
+	if c.Command.Happened() {
+		info, err := catFile(*c.fileInput, *c.shouldShowObjectType, *c.shouldShowSize)
+		if err != nil {
+			fmt.Println(err)
+		} else {
+			fmt.Println(info)
+		}
+		return true
+	}
+	return false
+}
+
+func catFile(oid string, shouldShowType, shouldShowSize bool) (string, error) {
+	objectInfo, err := object.Read(oid)
+	if err != nil {
+		return "", err
+	}
+
+	if shouldShowType && shouldShowSize {
+		err = fmt.Errorf("-t and -s cannot be used altogether")
+		return "", err
+	}
+
+	if shouldShowType {
+		return objectInfo.Type, nil
+	}
+	if shouldShowSize {
+		return strconv.Itoa(objectInfo.Size), nil
+	}
+	return string(objectInfo.Content), nil
+}

cmd/cat_test.go

@@ -0,0 +1,99 @@
+package cmd
+
+import (
+	"crypto/sha1"
+	"encoding/hex"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"micro-git/root"
+	"micro-git/testutil"
+
+	"github.com/stretchr/testify/suite"
+)
+
+type CatTestSuite struct {
+	suite.Suite
+	currWd    string
+	tmpDir    string
+	sampleOid string
+}
+
+func (suite *CatTestSuite) SetupSuite() {
+	currWd, err := os.Getwd()
+	if err != nil {
+		suite.FailNow("Failed to get current working directory", "Error: %v", err)
+	}
+
+	suite.currWd = currWd
+
+	tmpDir := testutil.CreateTestDir(suite.T())
+	suite.tmpDir = tmpDir
+
+	err = os.WriteFile("test.txt", []byte("Hello"), 0o664)
+	if err != nil {
+		suite.FailNow("Failed to create test.txt file for testing", "Error: %v", err)
+	}
+
+	// create the .microgit folder
+	err = root.InitDB()
+	if err != nil {
+		suite.FailNow("Failed to execute Init command", "Error: %v", err)
+	}
+
+	// hash the test.txt file
+	combined := append([]byte("blob"), []byte(" 5")...)
+	combined = append(combined, '\x00')
+	combined = append(combined, []byte("Hello")...)
+	shaSum := sha1.Sum(combined)
+	hexSum := hex.EncodeToString(shaSum[:])
+
+	suite.sampleOid = hexSum
+
+	folderPath := filepath.Join(".microgit", "objects", hexSum[:2])
+	objectPath := filepath.Join(folderPath, hexSum[2:])
+
+	err = os.MkdirAll(folderPath, 0o774)
+	if err != nil {
+		suite.FailNow("Failed to create folder for hashed file of test.txt", "Error: %v", err)
+	}
+
+	err = os.WriteFile(objectPath, combined, 0o664)
+	if err != nil {
+		suite.FailNow("Failed to create hashed file of test.txt", "Error: %v", err)
+	}
+}
+
+func (suite *CatTestSuite) TearDownSuite() {
+	os.RemoveAll(suite.tmpDir)
+	os.Chdir(suite.currWd)
+}
+
+func (suite *CatTestSuite) TestCatFileContentReturnCorrectResult() {
+	content, err := catFile(suite.sampleOid, false, false)
+	if err != nil {
+		suite.FailNow("catFile failed", "Error: %v", err)
+	}
+	suite.Equal("Hello", string(content))
+}
+
+func (suite *CatTestSuite) TestCatFileTypeReturnCorrectResult() {
+	fileType, err := catFile(suite.sampleOid, true, false)
+	if err != nil {
+		suite.FailNow("catFile failed", "Error: %v", err)
+	}
+	suite.Equal("blob", fileType)
+}
+
+func (suite *CatTestSuite) TestCatFileSizeReturnCorrectResult() {
+	fileSize, err := catFile(suite.sampleOid, false, true)
+	if err != nil {
+		suite.FailNow("catFile failed", "Error: %v", err)
+	}
+	suite.Equal("5", fileSize)
+}
+
+func TestCatTestSuite(t *testing.T) {
+	suite.Run(t, new(CatTestSuite))
+}