import type { WorkspaceMergePreview } from "agent-relay-sdk";
import { prMergedState } from "../workspace-pr";

// Populate a preview's PR fields from `gh` ground truth; returns whether the PR is merged
// (#168/#304). One home for the PR-landing rule so the worktree- and repoRoot-based previews
// can't drift. On a merge it stamps the merge SHA so the relay can finalize a parked pr land.
export async function applyPrMergeState(base: WorkspaceMergePreview, cwd: string, branch: string | undefined): Promise<boolean> {
  const pr = await prMergedState(cwd, branch);
  if (!pr) return false;
  base.prState = pr.state;
  if (pr.url) base.prUrl = pr.url;
  if (pr.number) base.prNumber = pr.number;
  if (pr.reviewDecision) base.reviewDecision = pr.reviewDecision;
  if (pr.statusCheckRollup) base.statusCheckRollup = pr.statusCheckRollup;
  if (pr.mergeable) base.mergeable = pr.mergeable;
  if (pr.mergeStateStatus) base.mergeStateStatus = pr.mergeStateStatus;
  if (pr.state !== "merged") return false;
  base.prMerged = true;
  if (pr.sha) base.prMergeSha = pr.sha;
  if (pr.title) base.prMergeSubject = pr.title;
  return true;
}