bug: implement comment edition

- add a new operation
- add a new "timeline" in the snapshot that hold a processed version of the operations

1 files changed, 123 insertions, 0 deletions

diff --git a/bug/op_edit_comment.go b/bug/op_edit_comment.go
new file mode 100644
index 00000000..c6cfab2b
--- /dev/null
+++ b/bug/op_edit_comment.go
@@ -0,0 +1,123 @@
+package bug
+
+import (
+	"fmt"
+
+	"github.com/MichaelMure/git-bug/util/git"
+	"github.com/MichaelMure/git-bug/util/text"
+)
+
+var _ Operation = &EditCommentOperation{}
+
+// EditCommentOperation will change a comment in the bug
+type EditCommentOperation struct {
+	*OpBase
+	Target  git.Hash   `json:"target"`
+	Message string     `json:"message"`
+	Files   []git.Hash `json:"files"`
+}
+
+func (op *EditCommentOperation) base() *OpBase {
+	return op.OpBase
+}
+
+func (op *EditCommentOperation) Hash() (git.Hash, error) {
+	return hashOperation(op)
+}
+
+func (op *EditCommentOperation) Apply(snapshot *Snapshot) {
+	// Todo: currently any message can be edited, even by a different author
+	// crypto signature are needed.
+
+	var target TimelineItem
+	var commentIndex int
+
+	for i, item := range snapshot.Timeline {
+		h, err := item.Hash()
+
+		if err != nil {
+			// Should never happen, we control what goes into the timeline
+			panic(err)
+		}
+
+		if h == op.Target {
+			target = snapshot.Timeline[i]
+			break
+		}
+
+		// Track the index in the []Comment
+		switch item.(type) {
+		case *CreateTimelineItem, *CommentTimelineItem:
+			commentIndex++
+		}
+	}
+
+	if target == nil {
+		// Target not found, edit is a no-op
+		return
+	}
+
+	switch target.(type) {
+	case *CreateTimelineItem:
+		item := target.(*CreateTimelineItem)
+		newComment := item.LastState()
+		newComment.Message = op.Message
+		item.History = append(item.History, newComment)
+
+	case *CommentTimelineItem:
+		item := target.(*CommentTimelineItem)
+		newComment := item.LastState()
+		newComment.Message = op.Message
+		item.History = append(item.History, newComment)
+	}
+
+	snapshot.Comments[commentIndex].Message = op.Message
+	snapshot.Comments[commentIndex].Files = op.Files
+}
+
+func (op *EditCommentOperation) GetFiles() []git.Hash {
+	return op.Files
+}
+
+func (op *EditCommentOperation) Validate() error {
+	if err := opBaseValidate(op, EditCommentOp); err != nil {
+		return err
+	}
+
+	if !op.Target.IsValid() {
+		return fmt.Errorf("target hash is invalid")
+	}
+
+	if text.Empty(op.Message) {
+		return fmt.Errorf("message is empty")
+	}
+
+	if !text.Safe(op.Message) {
+		return fmt.Errorf("message is not fully printable")
+	}
+
+	return nil
+}
+
+func NewEditCommentOp(author Person, unixTime int64, target git.Hash, message string, files []git.Hash) *EditCommentOperation {
+	return &EditCommentOperation{
+		OpBase:  newOpBase(EditCommentOp, author, unixTime),
+		Target:  target,
+		Message: message,
+		Files:   files,
+	}
+}
+
+// Convenience function to apply the operation
+func EditComment(b Interface, author Person, unixTime int64, target git.Hash, message string) error {
+	return EditCommentWithFiles(b, author, unixTime, target, message, nil)
+}
+
+func EditCommentWithFiles(b Interface, author Person, unixTime int64, target git.Hash, message string, files []git.Hash) error {
+	editCommentOp := NewEditCommentOp(author, unixTime, target, message, files)
+	if err := editCommentOp.Validate(); err != nil {
+		return err
+	}
+	b.Append(editCommentOp)
+	return nil
+}