// Fast-forward spawn (#67): one keystroke, every default resolved, no form.
// Pure resolution only — the caller (main.ts) owns the fetches and the POST,
// and falls back to a seeded draft pane when anything is missing.

import type { CreateSessionRequest, Project, SpawnPreset } from "./types.js";
import { sortProjects } from "./projectList.js";

/** What one fast-forward keystroke resolved. Anything absent means "open a
 *  draft pre-filled with the rest instead of spawning". */
export interface FastForwardResolution {
  project?: Project;
  command?: string;
  name?: string;
}

/** The defaults: most recent project (fresh-first, same ordering the picker
 *  shows), its last command falling back to the first non-custom preset, and
 *  a freshly generated name when the daemon supplied one. */
export function resolveFastForward(
  projects: Project[],
  presets: SpawnPreset[],
  name?: string,
): FastForwardResolution {
  const project = sortProjects(projects, new Date())[0];
  const lastCommand = project?.last_command?.trim();
  const command =
    lastCommand || presets.find((p) => p.command !== "")?.command || undefined;
  return { project, command, name: name || undefined };
}

/** The immediate spawn request — worktree on, new branch named after the
 *  generated session name — or `null` when any default is missing. */
export function buildFastForwardRequest(
  res: FastForwardResolution,
): CreateSessionRequest | null {
  const { project, command, name } = res;
  if (!project || !command?.trim() || !name) return null;
  return {
    cwd: project.path,
    command,
    metadata: { name },
    worktree: {
      base_repo: project.base_repo ?? project.path,
      branch: name,
      create_branch: true,
    },
  };
}

/** Seed for the fallback draft pane: whatever did resolve goes into the
 *  form; the rest stays with its own defaults. */
export function fastForwardSeed(res: FastForwardResolution) {
  return {
    cwd: res.project?.path ?? "",
    command: res.command ?? "",
    name: res.name ?? "",
    // Left undefined rather than false when nothing resolved: the form
    // defaults the toggle on, and `false` would stick, so the fallback draft
    // would disagree with both a normally-opened draft and the TUI's fast path
    // (#67 review).
    worktreeEnabled: res.project ? true : undefined,
    worktreeBranch:
      res.project && res.name ? res.name : undefined,
  };
}