Add todo mode and replace the plan with TODO.md

internal/agents/tasks.go

@@ -13,9 +13,58 @@ import (
 	"g.fc.run/misc/byre/internal/git"
 	"g.fc.run/misc/byre/internal/mcp"
 	"g.fc.run/misc/byre/internal/store"
+	"g.fc.run/misc/byre/internal/todo"
 )
 
 func (m *Manager) CreateTask(ctx context.Context, project api.Project, title, createdBy, base string) (api.Task, error) {
+	return m.createTask(ctx, project, title, createdBy, base, nil)
+}
+
+func (m *Manager) StartTodo(ctx context.Context, project api.Project, creator api.User, title, model string) (api.Task, error) {
+	if creator.GitName == "" || creator.GitEmail == "" {
+		return api.Task{}, ErrNoGitIdentity
+	}
+
+	src, found, err := git.ReadFile(project.RepoPath, project.DefaultBranch, todo.File)
+	if err != nil {
+		return api.Task{}, err
+	}
+	if !found {
+		return api.Task{}, fmt.Errorf("%w: %s has no %s", store.ErrNotFound, project.DefaultBranch, todo.File)
+	}
+	item, found := todo.Find(todo.Parse(src), title)
+	if !found {
+		return api.Task{}, fmt.Errorf("%w: %s on %s has no item %q", store.ErrNotFound, todo.File, project.DefaultBranch, title)
+	}
+
+	tasks, err := m.store.ListTasks(ctx, project.Id)
+	if err != nil {
+		return api.Task{}, err
+	}
+	for _, t := range tasks {
+		if t.Status == api.TaskStatusActive && t.TodoItem != nil && *t.TodoItem == title {
+			return api.Task{}, fmt.Errorf("%w: task %s is already working on %q", ErrConflict, t.Id, title)
+		}
+	}
+
+	task, err := m.createTask(ctx, project, item.Title, creator.Login, project.DefaultBranch, &item.Title)
+	if err != nil {
+		return api.Task{}, err
+	}
+
+	_, err = m.create(ctx, task, creator, todoPrompt(item), model, creator.Login, nil)
+	if err != nil {
+		return api.Task{}, fmt.Errorf("task %s created, but its agent did not start: %w", task.Id, err)
+	}
+	return task, nil
+}
+
+func todoPrompt(item api.TodoItem) string {
+	return fmt.Sprintf("Work on this item from %[1]s at the repo root:\n\n%[2]s\n\nWhen the work is done, remove this item from %[1]s in this worktree, so the removal lands in the same merge as the work.",
+		todo.File, todo.Markdown(item))
+}
+
+func (m *Manager) createTask(ctx context.Context, project api.Project, title, createdBy, base string, todoItem *string) (api.Task, error) {
 	id := store.NewID()
 	t := api.Task{
 		Id:           id,
@@ -27,6 +76,7 @@ func (m *Manager) CreateTask(ctx context.Context, project api.Project, title, cr
 		Status:       api.TaskStatusActive,
 		CreatedBy:    createdBy,
 		CreatedAt:    time.Now().UTC(),
+		TodoItem:     todoItem,
 	}
 
 	var err error