From e5eff3a4409762ccf8c9a1fe6bdbf7e6b8570a1b Mon Sep 17 00:00:00 2001
From: George Aristy <george.aristy@gmail.com>
Date: Sun, 3 Mar 2019 09:05:35 -0500
Subject: [PATCH] (#31) --since filter

---
 cmd/go-gitlint/main.go           | 12 +++++++++---
 internal/commits/commits.go      | 20 ++++++++++++++++++++
 internal/commits/commits_test.go | 23 +++++++++++++++++++++++
 internal/issues/filters.go       |  4 ++++
 4 files changed, 56 insertions(+), 3 deletions(-)

diff --git a/cmd/go-gitlint/main.go b/cmd/go-gitlint/main.go
index 5aa9a96..bde81bf 100644
--- a/cmd/go-gitlint/main.go
+++ b/cmd/go-gitlint/main.go
@@ -27,7 +27,10 @@ import (
 //  They promote coupling across different components inside the same package.
 //  Figure out a way to remove these global variables. Whatever command line
 //  parser we choose should be able to auto-generate usage.
-var path = kingpin.Flag("path", `Path to the git repo ("." by default).`).Default(".").String() //nolint[gochecknoglobals]
+var (
+	path  = kingpin.Flag("path", `Path to the git repo ("." by default).`).Default(".").String()                                                                       //nolint[gochecknoglobals]
+	since = kingpin.Flag("since", `A date in "yyyy-MM-dd" format starting from which commits will be analyzed (default: "1970-01-01")`).Default("1970-01-01").String() //nolint[gochecknoglobals]
+)
 
 func main() {
 	configure()
@@ -37,8 +40,11 @@ func main() {
 				os.Stdout, "\n",
 				issues.Collected(
 					issues.Filters(),
-					commits.In(
-						repo.Filesystem(*path),
+					commits.Since(
+						*since,
+						commits.In(
+							repo.Filesystem(*path),
+						),
 					),
 				),
 			)(),
diff --git a/internal/commits/commits.go b/internal/commits/commits.go
index d2b4bcf..3b69bf5 100644
--- a/internal/commits/commits.go
+++ b/internal/commits/commits.go
@@ -16,6 +16,7 @@ package commits
 
 import (
 	"strings"
+	"time"
 
 	"github.com/llorllale/go-gitlint/internal/repo"
 	git "gopkg.in/src-d/go-git.v4"
@@ -34,6 +35,7 @@ type Commits func() []*Commit
 type Commit struct {
 	Hash    string
 	Message string
+	Date    time.Time
 }
 
 // ID is the commit's hash.
@@ -83,6 +85,7 @@ func In(repository repo.Repo) Commits {
 				&Commit{
 					Hash:    c.Hash.String(),
 					Message: c.Message,
+					Date:    c.Author.When,
 				},
 			)
 			return nil
@@ -90,3 +93,20 @@ func In(repository repo.Repo) Commits {
 		return commits
 	}
 }
+
+// Since returns commits authored since time t (format: yyyy-MM-dd).
+func Since(t string, cmts Commits) Commits {
+	return func() []*Commit {
+		start, err := time.Parse("2006-01-02", t)
+		if err != nil {
+			panic(err)
+		}
+		filtered := make([]*Commit, 0)
+		for _, c := range cmts() {
+			if !c.Date.Before(start) {
+				filtered = append(filtered, c)
+			}
+		}
+		return filtered
+	}
+}
diff --git a/internal/commits/commits_test.go b/internal/commits/commits_test.go
index 4b5ad2b..c2837f4 100644
--- a/internal/commits/commits_test.go
+++ b/internal/commits/commits_test.go
@@ -26,6 +26,7 @@ import (
 	"github.com/google/uuid"
 	"github.com/llorllale/go-gitlint/internal/repo"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	git "gopkg.in/src-d/go-git.v4"
 	"gopkg.in/src-d/go-git.v4/plumbing/object"
 )
@@ -75,6 +76,28 @@ func TestIn(t *testing.T) {
 	}
 }
 
+func TestSince(t *testing.T) {
+	before, err := time.Parse("2006-01-02", "2017-10-25")
+	require.NoError(t, err)
+	since, err := time.Parse("2006-01-02", "2019-01-01")
+	require.NoError(t, err)
+	after, err := time.Parse("2006-01-02", "2019-03-03")
+	require.NoError(t, err)
+	commits := Since(
+		"2019-01-01",
+		func() []*Commit {
+			return []*Commit{
+				{Date: before},
+				{Date: since},
+				{Date: after},
+			}
+		},
+	)()
+	assert.Len(t, commits, 2)
+	assert.Contains(t, commits, &Commit{Date: since})
+	assert.Contains(t, commits, &Commit{Date: after})
+}
+
 // A git repo initialized and with one commit per each of the messages provided.
 // This repo is created in a temporary directory; use the cleanup function
 // to delete it afterwards.
diff --git a/internal/issues/filters.go b/internal/issues/filters.go
index 2a014ed..897a3f3 100644
--- a/internal/issues/filters.go
+++ b/internal/issues/filters.go
@@ -34,6 +34,10 @@ var (
 type Filter func(*commits.Commit) Issue
 
 // Filters returns all filters configured by the user.
+// @todo #31 Function issues.Filters() can be removed by providing
+//  default values for each filter that will effectively render them
+//  disabled. For example, OfSubjectRegex() can be effectively disabled
+//  by using ".*" as regex.
 func Filters() []Filter {
 	filters := make([]Filter, 0)
 	if subjectRegex != nil {