vbvictor · vbvictor · Mar 14, 2025 · Mar 14, 2025
diff --git a/grit/cmd/stat/subcommands/complexity.go b/grit/cmd/stat/subcommands/complexity.go
@@ -25,18 +25,18 @@ var ComplexityCmd = &cobra.Command{ //nolint:exhaustruct // no need to set all f
 	Short: "Finds the most complex files",
 	Args:  cobra.ExactArgs(1),
 	RunE: func(_ *cobra.Command, args []string) error {
-		repoPath, err := filepath.Abs(args[0])
+		path, err := filepath.Abs(args[0])
 		if err != nil {
 			return fmt.Errorf("error getting absolute path: %w", err)
 		}
 
-		flag.LogIfVerbose("Processing repository: %s\n", repoPath)
+		flag.LogIfVerbose("Processing repository: %s\n", path)
 
 		if err := complexity.PopulateOpts(&complexityOpts, excludeComplexityRegex); err != nil {
 			return fmt.Errorf("failed to create options: %w", err)
 		}
 
-		fileStat, err := complexity.RunComplexity(repoPath, &complexityOpts)
+		fileStat, err := complexity.RunComplexity(path, &complexityOpts)
 		if err != nil {
 			return fmt.Errorf("error running complexity analysis: %w", err)
 		}
@@ -51,7 +51,10 @@ func init() {
 	flags := ComplexityCmd.PersistentFlags()
 
 	flags.StringVarP(&complexityOpts.Engine, flag.LongEngine, flag.ShortEngine, complexity.Gocyclo,
-		fmt.Sprintf("Specify complexity calculation engine: [%s, %s]", complexity.Gocyclo, complexity.Gocognit))
+		fmt.Sprintf(`Specify complexity calculation engine: [%s, %s, %s].
+When CSV engine is chosen, GRIT will try to read function complexity data from CSV file specified by <path> parameter.
+The file should have following fields: "filename,function,complexity,line-count (optional),packages (optional)"
+`, complexity.Gocyclo, complexity.Gocognit, complexity.CSV))
 	flags.IntVarP(&complexityOpts.Top, flag.LongTop, flag.ShortTop, git.DefaultTop, "Number of top files to display")
 	flags.BoolVarP(&flag.Verbose, flag.LongVerbose, flag.ShortVerbose, false, "Show detailed progress")
 	flags.StringVar(&excludeComplexityRegex, flag.LongExclude, "", "Exclude files matching regex pattern")

diff --git a/pkg/complexity/csv.go b/pkg/complexity/csv.go
@@ -0,0 +1,110 @@
+package complexity
+
+import (
+	"encoding/csv"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func RunCSV(filepath string, opts *Options) ([]*FileStat, error) {
+	file, err := os.Open(filepath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open CSV file at %s: %w", filepath, err)
+	}
+	defer file.Close()
+
+	functionStats, err := readComplexityFromCSV(file)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse complexity data from CSV: %w", err)
+	}
+
+	fileMap := make(map[string][]FunctionStat)
+	for _, stat := range functionStats {
+		fileMap[stat.File] = append(fileMap[stat.File], *stat)
+	}
+
+	result := make([]*FileStat, 0, len(fileMap))
+
+	for file, functions := range fileMap {
+		if opts.ExcludeRegex != nil && opts.ExcludeRegex.MatchString(file) {
+			continue
+		}
+
+		result = append(result, &FileStat{
+			Path:      file,
+			Functions: functions,
+		})
+	}
+
+	// Calculate average complexity for each file
+	AvgComplexity(result)
+
+	return result, nil
+}
+
+const minimalColumns = 4
+
+func readComplexityFromCSV(r io.Reader) ([]*FunctionStat, error) { //nolint:cyclop // complexity is not a problem here
+	csvReader := csv.NewReader(r)
+	csvReader.FieldsPerRecord = -1 // Allow variable number of fields per record
+
+	records, err := csvReader.ReadAll()
+	if err != nil {
+		return nil, fmt.Errorf("failed to read CSV data: %w", err)
+	}
+
+	if len(records) == 0 {
+		return nil, errors.New("CSV data is empty")
+	}
+
+	result := make([]*FunctionStat, 0, len(records))
+
+	for pos, record := range records {
+		// Minimum required fields: filename, function, length, complexity
+		if len(record) < minimalColumns {
+			return nil, fmt.Errorf("row %d: insufficient columns, expected at least 4", pos+1)
+		}
+
+		stat := &FunctionStat{
+			File: record[0],
+			Name: record[1],
+		}
+
+		length, err := strconv.Atoi(record[2])
+		if err != nil {
+			return nil, fmt.Errorf("row %d: invalid length value '%s': %w", pos+1, record[2], err)
+		}
+
+		stat.Length = length
+
+		complexity, err := strconv.Atoi(record[3])
+		if err != nil {
+			return nil, fmt.Errorf("row %d: invalid complexity value '%s': %w", pos+1, record[3], err)
+		}
+
+		stat.Complexity = complexity
+
+		// Optional: line number
+		if len(record) > 4 && record[4] != "" {
+			line, err := strconv.Atoi(record[4])
+			if err != nil {
+				return nil, fmt.Errorf("row %d: invalid line value '%s': %w", pos+1, record[4], err)
+			}
+
+			stat.Line = line
+		}
+
+		// Optional: packages
+		if len(record) > 5 && record[5] != "" {
+			stat.Package = strings.Split(record[5], ";")
+		}
+
+		result = append(result, stat)
+	}
+
+	return result, nil
+}
diff --git a/pkg/complexity/csv_test.go b/pkg/complexity/csv_test.go
@@ -0,0 +1,201 @@
+package complexity
+
+import (
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestReadComplexityFromCSV(t *testing.T) {
+	tests := []struct {
+		name    string
+		csv     string
+		want    []*FunctionStat
+		wantErr bool
+	}{
+		{
+			name: "valid csv with all fields",
+			csv: `filename.go,Calculate,120,15,42,pkg1;pkg2
+anothefile.go,Process,80,8,123,main`,
+			want: []*FunctionStat{
+				{
+					File:       "filename.go",
+					Name:       "Calculate",
+					Length:     120,
+					Complexity: 15,
+					Line:       42,
+					Package:    []string{"pkg1", "pkg2"},
+				},
+				{
+					File:       "anothefile.go",
+					Name:       "Process",
+					Length:     80,
+					Complexity: 8,
+					Line:       123,
+					Package:    []string{"main"},
+				},
+			},
+			wantErr: false,
+		},
+		{
+			name: "valid csv with header row",
+			csv:  `filename.go,Calculate,120,15,42,pkg1;pkg2`,
+			want: []*FunctionStat{
+				{
+					File:       "filename.go",
+					Name:       "Calculate",
+					Length:     120,
+					Complexity: 15,
+					Line:       42,
+					Package:    []string{"pkg1", "pkg2"},
+				},
+			},
+			wantErr: false,
+		},
+		{
+			name: "valid csv with minimum required fields",
+			csv: `filename.go,Calculate,120,15
+anothefile.go,Process,80,8`,
+			want: []*FunctionStat{
+				{
+					File:       "filename.go",
+					Name:       "Calculate",
+					Length:     120,
+					Complexity: 15,
+				},
+				{
+					File:       "anothefile.go",
+					Name:       "Process",
+					Length:     80,
+					Complexity: 8,
+				},
+			},
+			wantErr: false,
+		},
+		{
+			name: "valid csv with mixed field counts",
+			csv: `filename.go,Calculate,120,15,42
+anothefile.go,Process,80,8,,main`,
+			want: []*FunctionStat{
+				{
+					File:       "filename.go",
+					Name:       "Calculate",
+					Length:     120,
+					Complexity: 15,
+					Line:       42,
+				},
+				{
+					File:       "anothefile.go",
+					Name:       "Process",
+					Length:     80,
+					Complexity: 8,
+					Package:    []string{"main"},
+				},
+			},
+			wantErr: false,
+		},
+		{
+			name:    "empty csv",
+			csv:     "",
+			want:    nil,
+			wantErr: true,
+		},
+		{
+			name:    "insufficient columns",
+			csv:     "filename.go,Calculate,120",
+			want:    nil,
+			wantErr: true,
+		},
+		{
+			name:    "invalid length value",
+			csv:     "filename.go,Calculate,invalid,15",
+			want:    nil,
+			wantErr: true,
+		},
+		{
+			name:    "invalid complexity value",
+			csv:     "filename.go,Calculate,120,invalid",
+			want:    nil,
+			wantErr: true,
+		},
+		{
+			name:    "invalid line value",
+			csv:     "filename.go,Calculate,120,15,invalid",
+			want:    nil,
+			wantErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			reader := strings.NewReader(tt.csv)
+			got, err := readComplexityFromCSV(reader)
+
+			if tt.wantErr {
+				assert.Error(t, err)
+
+				return
+			}
+
+			require.NoError(t, err)
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}
+
+func TestRunCSV(t *testing.T) {
+	csvContent := `file1.go,func1,50,5,10,pkg1
+file1.go,func2,70,10,20,pkg1
+file2.go,func3,30,3,15,pkg2
+file3.go,func4,100,15,25,pkg3;pkg4`
+
+	csvPath := filepath.Join(t.TempDir(), "complexity.csv")
+	err := os.WriteFile(csvPath, []byte(csvContent), 0o600)
+
+	require.NoError(t, err)
+
+	opts := &Options{
+		Engine: CSV,
+		Top:    10,
+	}
+
+	results, err := RunCSV(csvPath, opts)
+	require.NoError(t, err)
+	assert.Len(t, results, 3)
+
+	expectedFiles := map[string]struct {
+		FunctionCount int
+		AvgComplexity float64
+	}{
+		"file1.go": {FunctionCount: 2, AvgComplexity: 7.5}, // (5+10)/2 = 7.5
+		"file2.go": {FunctionCount: 1, AvgComplexity: 3.0},
+		"file3.go": {FunctionCount: 1, AvgComplexity: 15.0},
+	}
+
+	for _, file := range results {
+		expected, exists := expectedFiles[file.Path]
+		assert.True(t, exists, "Unexpected file in results: %s", file.Path)
+
+		if exists {
+			assert.Len(t, file.Functions, expected.FunctionCount, "Incorrect function count for %s", file.Path)
+			assert.InEpsilon(t, expected.AvgComplexity, file.AvgComplexity, 0.001,
+				"Incorrect average complexity for %s", file.Path)
+		}
+	}
+
+	// Test with exclude regex
+	excludeOpts := &Options{
+		Engine:       CSV,
+		ExcludeRegex: regexp.MustCompile(`file[12]\.go`),
+	}
+
+	filteredResults, err := RunCSV(csvPath, excludeOpts)
+	require.NoError(t, err)
+	assert.Len(t, filteredResults, 1)
+	assert.Equal(t, "file3.go", filteredResults[0].Path)
+}
diff --git a/pkg/complexity/run.go b/pkg/complexity/run.go
@@ -12,6 +12,7 @@ type Engine = string
 const (
 	Gocyclo  = "gocyclo"
 	Gocognit = "gocognit"
+	CSV      = "csv-file"
 )
 
 type FileStat struct {
@@ -57,6 +58,8 @@ func RunComplexity(repoPath string, opts *Options) ([]*FileStat, error) {
 		return RunGocyclo(repoPath, opts)
 	case Gocognit:
 		return RunGocognit(repoPath, opts)
+	case CSV:
+		return RunCSV(repoPath, opts)
 	default:
 		return nil, ErrUnsupportedEngine
 	}