issue #70: proof of concept refactoring of diff command

Author: kamilsk

docs/changelog.md

@@ -68,7 +68,7 @@
       "2013-12-27T00:00:00Z": 2
     }
 
-    $ maintainer github contribution diff --base=/tmp/snap.01.2013.json 2013
+    $ maintainer github contribution diff /tmp/snap.01.2013.json 2013
      Day / Week                  #46             #48             #49           #50
     ---------------------- --------------- --------------- --------------- -----------
      Sunday                       -               -               -             -
@@ -81,7 +81,7 @@
     ---------------------- --------------- --------------- --------------- -----------
      The diff between head{"/tmp/snap.02.2013.json"} → base{"/tmp/snap.01.2013.json"}
 
-    $ maintainer github contribution diff --base=/tmp/snap.01.2013.json --head=/tmp/snap.02.2013.json
+    $ maintainer github contribution diff /tmp/snap.01.2013.json /tmp/snap.02.2013.json
     ```
 
   * Suggests a reasonable date to contribute

internal/command/github/contribution.go

@@ -12,7 +12,6 @@ import (
 	"go.octolab.org/toolset/maintainer/internal/command/github/view"
 	"go.octolab.org/toolset/maintainer/internal/config"
 	"go.octolab.org/toolset/maintainer/internal/model/github/contribution"
-	"go.octolab.org/toolset/maintainer/internal/pkg/config/flag"
 	"go.octolab.org/toolset/maintainer/internal/pkg/http"
 	"go.octolab.org/toolset/maintainer/internal/pkg/time"
 	"go.octolab.org/toolset/maintainer/internal/pkg/unsafe"
@@ -25,7 +24,7 @@ func Contribution(cnf *config.Tool) *cobra.Command {
 	}
 
 	//
-	// $ maintainer github contribution diff --base=/tmp/snap.01.2013.json --head=/tmp/snap.02.2013.json
+	// $ maintainer github contribution diff /tmp/snap.01.2013.json /tmp/snap.02.2013.json
 	//
 	//  Day / Week                  #46             #48             #49           #50
 	// ---------------------- --------------- --------------- --------------- -----------
@@ -39,15 +38,13 @@ func Contribution(cnf *config.Tool) *cobra.Command {
 	// ---------------------- --------------- --------------- --------------- -----------
 	//  The diff between head{"/tmp/snap.02.2013.json"} → base{"/tmp/snap.01.2013.json"}
 	//
-	// $ maintainer github contribution diff --base=/tmp/snap.01.2013.json 2013
+	// $ maintainer github contribution diff /tmp/snap.01.2013.json 2013
 	//
 	diff := cobra.Command{
 		Use:  "diff",
-		Args: cobra.MaximumNArgs(1),
+		Args: cobra.ExactArgs(2),
 		RunE: exec.ContributionDiff(cnf),
 	}
-	flag.Adopt(diff.Flags()).File("base", "", "path to a base file")
-	flag.Adopt(diff.Flags()).File("head", "", "path to a head file")
 	cmd.AddCommand(&diff)
 
 	//

internal/command/github/exec/contribution_diff.go

@@ -2,66 +2,69 @@ package exec
 
 import (
 	"fmt"
+	"regexp"
 
 	"github.com/spf13/cobra"
 
 	"go.octolab.org/toolset/maintainer/internal/command/github/run"
 	"go.octolab.org/toolset/maintainer/internal/config"
-	"go.octolab.org/toolset/maintainer/internal/pkg/config/flag"
+	"go.octolab.org/toolset/maintainer/internal/model/github/contribution"
 	"go.octolab.org/toolset/maintainer/internal/pkg/http"
 	"go.octolab.org/toolset/maintainer/internal/pkg/time"
 	"go.octolab.org/toolset/maintainer/internal/service/github"
 )
 
 func ContributionDiff(cnf *config.Tool) Runner {
+	isYear := regexp.MustCompile(`^\d{4}$`)
+	wrap := func(err error, input string) error {
+		return fmt.Errorf(
+			"please provide the argument in format YYYY, e.g., 2006: %w",
+			fmt.Errorf("invalid argument %q: %w", input, err),
+		)
+	}
+
+	// input validation:
+	//  - Args: cobra.ExactArgs(2)
+	//  - base{file|date(year)} head{file|date(year)}
 	return func(cmd *cobra.Command, args []string) error {
 		service := github.New(http.TokenSourcedClient(cmd.Context(), cnf.Token))
-		date := time.TruncateToYear(time.Now().UTC())
-
-		// input validation: files{params}, date(year){args}
-		var baseSource, headSource string
-		dst, err := flag.Adopt(cmd.Flags()).GetFile("base")
-		if err != nil {
-			return err
-		}
-		if dst == nil {
-			return fmt.Errorf("please provide a base file by `--base` parameter")
-		}
-		baseSource = dst.Name()
 
-		src, err := flag.Adopt(cmd.Flags()).GetFile("head")
-		if err != nil {
-			return err
-		}
-		if src == nil && len(args) == 0 {
-			return fmt.Errorf("please provide a compared file by `--head` parameter or year in args")
-		}
-		if src != nil && len(args) > 0 {
-			return fmt.Errorf("please omit `--head` or argument, only one of them is allowed")
-		}
-		if len(args) == 1 {
-			var err error
-			wrap := func(err error) error {
-				return fmt.Errorf(
-					"please provide argument in format YYYY, e.g., 2006: %w",
-					fmt.Errorf("invalid argument %q: %w", args[0], err),
-				)
+		var base run.ContributionSource
+		if input := args[0]; isYear.MatchString(input) {
+			year, err := time.Parse(time.RFC3339Year, input)
+			if err != nil {
+				return wrap(err, input)
 			}
 
-			switch input := args[0]; len(input) {
-			case len(time.RFC3339Year):
-				date, err = time.Parse(time.RFC3339Year, input)
-			default:
-				err = fmt.Errorf("unsupported format")
+			base = &contribution.UpstreamSource{
+				Provider: service,
+				Year:     year,
+			}
+		} else {
+			base = &contribution.FileSource{
+				Provider: cnf.FS,
+				Path:     input,
 			}
+		}
+
+		var head run.ContributionSource
+		if input := args[1]; isYear.MatchString(input) {
+			year, err := time.Parse(time.RFC3339Year, input)
 			if err != nil {
-				return wrap(err)
+				return wrap(err, input)
+			}
+
+			head = &contribution.UpstreamSource{
+				Provider: service,
+				Year:     year,
 			}
-			headSource = fmt.Sprintf("upstream:year(%s)", date.Format(time.RFC3339Year))
 		} else {
-			headSource = src.Name()
+			head = &contribution.FileSource{
+				Provider: cnf.FS,
+				Path:     input,
+			}
 		}
 
-		return run.ContributionDiff(cmd.Context(), service, cmd, date, dst, src, baseSource, headSource)
+		return run.ContributionDiff(cmd.Context(), base, head, cmd)
 	}
 }

internal/command/github/run/contract.go

@@ -4,11 +4,11 @@ import (
 	"context"
 
 	"go.octolab.org/toolset/maintainer/internal/model/github/contribution"
-	"go.octolab.org/toolset/maintainer/internal/pkg/time"
 )
 
-type Contributor interface {
-	ContributionHeatMap(context.Context, time.Range) (contribution.HeatMap, error)
+type ContributionSource interface {
+	Location() string
+	Fetch(context.Context) (contribution.HeatMap, error)
 }
 
 type Printer interface {

internal/command/github/run/contribution_diff.go

@@ -2,42 +2,24 @@ package run
 
 import (
 	"context"
-	"encoding/json"
-	"os"
 
 	"go.octolab.org/toolset/maintainer/internal/command/github/view"
-	"go.octolab.org/toolset/maintainer/internal/model/github/contribution"
-	"go.octolab.org/toolset/maintainer/internal/pkg/time"
 )
 
 func ContributionDiff(
 	ctx context.Context,
-	service Contributor,
+	src, dst ContributionSource,
 	printer Printer,
-
-	date time.Time,
-	src, dst *os.File,
-	baseSource, headSource string,
 ) error {
-	var (
-		base contribution.HeatMap
-		head contribution.HeatMap
-	)
-	if err := json.NewDecoder(dst).Decode(&base); err != nil {
+	base, err := src.Fetch(ctx)
+	if err != nil {
 		return err
 	}
-	if src != nil {
-		if err := json.NewDecoder(src).Decode(&head); err != nil {
-			return err
-		}
-	} else {
-		var err error
-		scope := time.RangeByYears(date, 0, false).ExcludeFuture()
-		head, err = service.ContributionHeatMap(ctx, scope)
-		if err != nil {
-			return err
-		}
+
+	head, err := dst.Fetch(ctx)
+	if err != nil {
+		return err
 	}
 
-	return view.ContributionDiff(printer, base.Diff(head), baseSource, headSource)
+	return view.ContributionDiff(printer, base.Diff(head), src.Location(), dst.Location())
 }

internal/command/root.go

@@ -23,7 +23,7 @@ func New() *cobra.Command {
 
 		PersistentPreRunE: func(*cobra.Command, []string) error {
 			// TODO:feature home dir and specific config
-			return cnf.Load(afero.NewMemMapFs())
+			return cnf.Load(afero.NewOsFs())
 		},
 
 		SilenceErrors: false,

internal/config/tool.go

@@ -18,6 +18,7 @@ type GitHub struct {
 }
 
 type Tool struct {
+	FS     afero.Fs `mapstructure:"-"`
 	Git    `mapstructure:"git,squash"`
 	GitHub `mapstructure:"github,squash"`
 
@@ -40,8 +41,9 @@ func (cnf *Tool) Bind(bind func(*viper.Viper) error) error {
 
 func (cnf *Tool) Load(fs afero.Fs, bindings ...func(*viper.Viper) error) error {
 	v := cnf.init().config
-
 	v.SetFs(fs)
+	cnf.FS = fs
+
 	for _, bind := range bindings {
 		if err := bind(v); err != nil {
 			return err

internal/model/github/contribution/contract.go

@@ -0,0 +1,11 @@
+package contribution
+
+import (
+	"context"
+
+	"go.octolab.org/toolset/maintainer/internal/pkg/time"
+)
+
+type Contributor interface {
+	ContributionHeatMap(context.Context, time.Range) (HeatMap, error)
+}

internal/model/github/contribution/source.go

@@ -0,0 +1,77 @@
+package contribution
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/spf13/afero"
+	"go.octolab.org/safe"
+	"go.octolab.org/unsafe"
+	"gopkg.in/yaml.v2"
+
+	xtime "go.octolab.org/toolset/maintainer/internal/pkg/time"
+)
+
+type FileSource struct {
+	Provider afero.Fs
+	Path     string
+
+	data HeatMap
+}
+
+func (src FileSource) Location() string {
+	return fmt.Sprintf("file:%s", src.Path)
+}
+
+func (src *FileSource) Fetch(_ context.Context) (HeatMap, error) {
+	if src.data != nil {
+		return src.data, nil
+	}
+
+	file, err := src.Provider.Open(src.Path)
+	if err != nil {
+		return nil, err
+	}
+	defer safe.Close(file, unsafe.Ignore)
+
+	var data HeatMap
+	format := strings.ToLower(filepath.Ext(file.Name()))
+	switch format {
+	case ".json":
+		err := json.NewDecoder(file).Decode(&data)
+		src.data = data
+		return data, err
+	case ".yml", ".yaml":
+		err := yaml.NewDecoder(file).Decode(&data)
+		src.data = data
+		return data, err
+	default:
+		return nil, fmt.Errorf("unsupported format: %s", format)
+	}
+}
+
+type UpstreamSource struct {
+	Provider Contributor
+	Year     time.Time
+
+	data HeatMap
+}
+
+func (src UpstreamSource) Location() string {
+	return fmt.Sprintf("upstream:year(%s)", src.Year.Format(xtime.RFC3339Year))
+}
+
+func (src *UpstreamSource) Fetch(ctx context.Context) (HeatMap, error) {
+	if src.data != nil {
+		return src.data, nil
+	}
+
+	var err error
+	scope := xtime.RangeByYears(src.Year, 0, false).ExcludeFuture()
+	src.data, err = src.Provider.ContributionHeatMap(ctx, scope)
+	return src.data, err
+}