commands: add a package to handle implicit bug selection

1 files changed, 125 insertions, 0 deletions

diff --git a/commands/select/select.go b/commands/select/select.go
new file mode 100644
index 00000000..5d6cee7f
--- /dev/null
+++ b/commands/select/select.go
@@ -0,0 +1,125 @@
+package _select
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path"
+
+	"github.com/MichaelMure/git-bug/bug"
+	"github.com/MichaelMure/git-bug/cache"
+	"github.com/MichaelMure/git-bug/repository"
+	"github.com/MichaelMure/git-bug/util/git"
+	"github.com/pkg/errors"
+)
+
+const selectFile = "select"
+
+var ErrNoValidId = errors.New("you must provide a bug id")
+
+// ResolveBug first try to resolve a bug using the first argument of the command
+// line. If it fails, it fallback to the select mechanism.
+//
+// Returns:
+// - the bug if any
+// - the new list of command line arguments with the bug prefix removed if it
+//   has been used
+// - an error if the process failed
+func ResolveBug(repo *cache.RepoCache, args []string) (*cache.BugCache, []string, error) {
+	if len(args) > 0 {
+		b, err := repo.ResolveBugPrefix(args[0])
+
+		if err == nil {
+			return b, args[1:], nil
+		}
+
+		if err != bug.ErrBugNotExist {
+			return nil, nil, err
+		}
+	}
+
+	// first arg is not a valid bug prefix
+
+	b, err := selected(repo)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	if b != nil {
+		return b, args, nil
+	}
+
+	return nil, nil, ErrNoValidId
+}
+
+// Select will select a bug for future use
+func Select(repo *cache.RepoCache, id string) error {
+	selectPath := selectFilePath(repo.Repository())
+
+	f, err := os.OpenFile(selectPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
+	if err != nil {
+		return err
+	}
+
+	_, err = f.WriteString(id)
+	if err != nil {
+		return err
+	}
+
+	return f.Close()
+}
+
+// Clear will clear the selected bug, if any
+func Clear(repo *cache.RepoCache) error {
+	selectPath := selectFilePath(repo.Repository())
+
+	return os.Remove(selectPath)
+}
+
+func selected(repo *cache.RepoCache) (*cache.BugCache, error) {
+	selectPath := selectFilePath(repo.Repository())
+
+	f, err := os.Open(selectPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, nil
+		} else {
+			return nil, err
+		}
+	}
+
+	buf, err := ioutil.ReadAll(io.LimitReader(f, 100))
+	if err != nil {
+		return nil, err
+	}
+	if len(buf) == 100 {
+		return nil, fmt.Errorf("the select file should be < 100 bytes")
+	}
+
+	h := git.Hash(buf)
+	if !h.IsValid() {
+		err = os.Remove(selectPath)
+		if err != nil {
+			return nil, errors.Wrap(err, "error while removing invalid select file")
+		}
+
+		return nil, fmt.Errorf("select file in invalid, removing it")
+	}
+
+	b, err := repo.ResolveBug(string(h))
+	if err != nil {
+		return nil, err
+	}
+
+	err = f.Close()
+	if err != nil {
+		return nil, err
+	}
+
+	return b, nil
+}
+
+func selectFilePath(repo repository.Repo) string {
+	return path.Join(repo.GetPath(), ".git", "git-bug", selectFile)
+}