1 files changed, 249 insertions, 0 deletions
diff --git a/commands/patch/rebase.go b/commands/patch/rebase.go
new file mode 100644
index 00000000..10da2a63
--- /dev/null
+++ b/commands/patch/rebase.go
@@ -0,0 +1,249 @@
+package patch
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"sort"
+	"strings"
+	"time"
+
+	"git.sr.ht/~rjarry/aerc/app"
+	"git.sr.ht/~rjarry/aerc/config"
+	"git.sr.ht/~rjarry/aerc/lib/pama"
+	"git.sr.ht/~rjarry/aerc/lib/pama/models"
+	"git.sr.ht/~rjarry/aerc/lib/ui"
+	"git.sr.ht/~rjarry/aerc/log"
+)
+
+type Rebase struct {
+	Commit string `opt:"commit" required:"false"`
+}
+
+func init() {
+	register(Rebase{})
+}
+
+func (Rebase) Aliases() []string {
+	return []string{"rebase"}
+}
+
+func (r Rebase) Execute(args []string) error {
+	m := pama.New()
+	current, err := m.CurrentProject()
+	if err != nil {
+		return err
+	}
+
+	baseID := r.Commit
+	if baseID == "" {
+		baseID = current.Base.ID
+	}
+
+	commits, err := m.RebaseCommits(current, baseID)
+	if err != nil {
+		return err
+	}
+
+	if len(commits) == 0 {
+		err := m.SaveRebased(current, baseID, nil)
+		if err != nil {
+			return fmt.Errorf("No commits to rebase, but saving of new reference failed: %w", err)
+		}
+		app.PushStatus("No commits to rebase.", 10*time.Second)
+		return nil
+	}
+
+	rebase := newRebase(commits)
+	f, err := os.CreateTemp("", "aerc-patch-rebase-*")
+	if err != nil {
+		return err
+	}
+	name := f.Name()
+	_, err = io.Copy(f, rebase.content())
+	if err != nil {
+		return err
+	}
+	f.Close()
+
+	createWidget := func() (ui.DrawableInteractive, error) {
+		editorCmd, err := app.CmdFallbackSearch(config.EditorCmds(), true)
+		if err != nil {
+			return nil, err
+		}
+		editor := exec.Command("/bin/sh", "-c", editorCmd+" "+name)
+		term, err := app.NewTerminal(editor)
+		if err != nil {
+			return nil, err
+		}
+		term.OnClose = func(_ error) {
+			app.CloseDialog()
+			defer os.Remove(name)
+			defer term.Focus(false)
+
+			f, err := os.Open(name)
+			if err != nil {
+				app.PushError(fmt.Sprintf("failed to open file: %v", err))
+				return
+			}
+			defer f.Close()
+
+			if editor.ProcessState.ExitCode() > 0 {
+				app.PushError("Quitting rebase without saving.")
+				return
+			}
+			err = m.SaveRebased(current, baseID, rebase.parse(f))
+			if err != nil {
+				app.PushError(fmt.Sprintf("Failed to save rebased commits: %v", err))
+				return
+			}
+			app.PushStatus("Successfully rebased.", 10*time.Second)
+		}
+		term.Show(true)
+		term.Focus(true)
+		return term, nil
+	}
+
+	viewer, err := createWidget()
+	if err != nil {
+		return err
+	}
+
+	app.AddDialog(app.NewDialog(
+		ui.NewBox(viewer, fmt.Sprintf("Patch Rebase on %-6.6s", baseID), "",
+			app.SelectedAccountUiConfig(),
+		),
+		// start pos on screen
+		func(h int) int {
+			return h / 8
+		},
+		// dialog height
+		func(h int) int {
+			return h - 2*h/8
+		},
+	))
+
+	return nil
+}
+
+type rebase struct {
+	commits []models.Commit
+	table   map[string]models.Commit
+	order   []string
+}
+
+func newRebase(commits []models.Commit) *rebase {
+	return &rebase{
+		commits: commits,
+		table:   make(map[string]models.Commit),
+	}
+}
+
+const (
+	header string = ""
+	footer string = `
+# Rebase aerc's patch data. This will not affect the underlying repository in
+# any way.
+#
+# Change the name in the first column to assign a new tag to a commit. To group
+# multiple commits, use the same tag name.
+#
+# An 'untracked' tag indicates that aerc lost track of that commit, either due
+# to a commit-hash change or because that commit was applied outside of aerc.
+#
+# Do not change anything else besides the tag names (first column).
+#
+# Do not reorder the lines. The ordering should remain as in the repository.
+#
+# If you remove a line or keep an 'untracked' tag, those commits will be removed
+# from aerc's patch tracking.
+#
+`
+)
+
+func (r *rebase) content() io.Reader {
+	var buf bytes.Buffer
+	buf.WriteString(header)
+	for _, c := range r.commits {
+		tag := c.Tag
+		if tag == "" {
+			tag = models.Untracked
+		}
+		shortHash := fmt.Sprintf("%6.6s", c.ID)
+		buf.WriteString(
+			fmt.Sprintf("%-12s     %6.6s     %s\n", tag, shortHash, c.Info()))
+		r.table[shortHash] = c
+		r.order = append(r.order, shortHash)
+	}
+	buf.WriteString(footer)
+	return &buf
+}
+
+func (r *rebase) parse(reader io.Reader) []models.Commit {
+	var commits []models.Commit
+	var hashes []string
+	scanner := bufio.NewScanner(reader)
+	duplicated := make(map[string]struct{})
+	for scanner.Scan() {
+		s := scanner.Text()
+		i := strings.Index(s, "#")
+		if i >= 0 {
+			s = s[:i]
+		}
+		if strings.TrimSpace(s) == "" {
+			continue
+		}
+
+		fds := strings.Fields(s)
+		if len(fds) < 2 {
+			continue
+		}
+
+		tag, shortHash := fds[0], fds[1]
+		if tag == models.Untracked {
+			continue
+		}
+		_, dedup := duplicated[shortHash]
+		if dedup {
+			log.Warnf("rebase: skipping duplicated hash: %s", shortHash)
+			continue
+		}
+
+		hashes = append(hashes, shortHash)
+		c, ok := r.table[shortHash]
+		if !ok {
+			log.Errorf("Looks like the commit hashes were changed "+
+				"during the rebase. Dropping: %v", shortHash)
+			continue
+		}
+		log.Tracef("save commit %s with tag %s", shortHash, tag)
+		c.Tag = tag
+		commits = append(commits, c)
+		duplicated[shortHash] = struct{}{}
+	}
+	reorder(commits, hashes, r.order)
+	return commits
+}
+
+func reorder(toSort []models.Commit, now []string, by []string) {
+	byMap := make(map[string]int)
+	for i, s := range by {
+		byMap[s] = i
+	}
+
+	complete := true
+	for _, s := range now {
+		_, ok := byMap[s]
+		complete = complete && ok
+	}
+	if !complete {
+		return
+	}
+
+	sort.SliceStable(toSort, func(i, j int) bool {
+		return byMap[now[i]] < byMap[now[j]]
+	})
+}