Move status loader into the git package

- Loading status belongs to git domain so it makes more sense for it to
  be in git package.
- It also makes the `list` file simpler.
- Because status loader is now part of the RepoFinder, the ugly Repo interface is no longer necessary.

pkg/git/status.go

@@ -0,0 +1,175 @@
+package git
+
+import (
+	"fmt"
+	"strings"
+)
+
+// Status contains human readable (and printable) representation of a git repository status.
+type Status struct {
+	path     string
+	current  string
+	branches map[string]string // key: branch name, value: branch status
+	worktree string
+	remote   string
+	errors   []string // Slice of errors which occurred when loading the status.
+}
+
+// LoadStatus reads status of a repository.
+// If fetch equals true, it first fetches from the remote repo before loading the status.
+// If errors occur during loading, they are stored in Status.errors slice.
+func (r *Repo) LoadStatus(fetch bool) *Status {
+	status := &Status{
+		path:     r.path,
+		branches: make(map[string]string),
+		errors:   make([]string, 0),
+	}
+
+	if fetch {
+		if err := r.Fetch(); err != nil {
+			status.errors = append(status.errors, err.Error())
+		}
+	}
+
+	var err error
+	status.current, err = r.CurrentBranch()
+	if err != nil {
+		status.errors = append(status.errors, err.Error())
+	}
+
+	var errs []error
+	status.branches, errs = r.loadBranches()
+	for _, err := range errs {
+		status.errors = append(status.errors, err.Error())
+	}
+
+	status.worktree, err = r.loadWorkTree()
+	if err != nil {
+		status.errors = append(status.errors, err.Error())
+	}
+
+	status.remote, err = r.Remote()
+	if err != nil {
+		status.errors = append(status.errors, err.Error())
+	}
+
+	return status
+}
+
+func (r *Repo) loadBranches() (map[string]string, []error) {
+	statuses := make(map[string]string)
+	errors := make([]error, 0)
+
+	branches, err := r.Branches()
+	if err != nil {
+		errors = append(errors, err)
+		return statuses, errors
+	}
+
+	for _, branch := range branches {
+		status, err := r.loadBranchStatus(branch)
+		statuses[branch] = status
+		if err != nil {
+			errors = append(errors, err)
+		}
+	}
+
+	return statuses, errors
+}
+
+func (r *Repo) loadBranchStatus(branch string) (string, error) {
+	upstream, err := r.Upstream(branch)
+	if err != nil {
+		return "", err
+	}
+
+	if upstream == "" {
+		return "no upstream", nil
+	}
+
+	ahead, behind, err := r.AheadBehind(branch, upstream)
+	if err != nil {
+		return "", err
+	}
+
+	if ahead == 0 && behind == 0 {
+		return "", nil
+	}
+
+	var res []string
+	if ahead != 0 {
+		res = append(res, fmt.Sprintf("%d ahead", ahead))
+	}
+	if behind != 0 {
+		res = append(res, fmt.Sprintf("%d behind", behind))
+	}
+
+	return strings.Join(res, " "), nil
+}
+
+func (r *Repo) loadWorkTree() (string, error) {
+	uncommitted, err := r.Uncommitted()
+	if err != nil {
+		return "", err
+	}
+
+	untracked, err := r.Untracked()
+	if err != nil {
+		return "", err
+	}
+
+	if uncommitted == 0 && untracked == 0 {
+		return "", nil
+	}
+
+	var res []string
+	if uncommitted != 0 {
+		res = append(res, fmt.Sprintf("%d uncommitted", uncommitted))
+	}
+	if untracked != 0 {
+		res = append(res, fmt.Sprintf("%d untracked", untracked))
+	}
+
+	return strings.Join(res, " "), nil
+}
+
+// Path returns path to a repository.
+func (s *Status) Path() string {
+	return s.path
+}
+
+// Current returns the name of currently checked out branch (or tag or detached HEAD).
+func (s *Status) Current() string {
+	return s.current
+}
+
+// Branches returns a list of all branches names except the currently checked out one. Use Current() to get its name.
+func (s *Status) Branches() []string {
+	var branches []string
+	for b := range s.branches {
+		if b != s.current {
+			branches = append(branches, b)
+		}
+	}
+	return branches
+}
+
+// BranchStatus returns status of a given branch
+func (s *Status) BranchStatus(branch string) string {
+	return s.branches[branch]
+}
+
+// WorkTreeStatus returns status of a worktree
+func (s *Status) WorkTreeStatus() string {
+	return s.worktree
+}
+
+// Remote returns URL to remote repository
+func (s *Status) Remote() string {
+	return s.remote
+}
+
+// Errors is a slice of errors that occurred when loading repo status
+func (s *Status) Errors() []string {
+	return s.errors
+}