#!/usr/bin/env bash
#
# wt-rm.sh — remove the worktree for a named branch.
#
# EXPLICIT BY DESIGN: it removes ONLY the branch you name. There is no
# scanning and no "is it merged into main?" heuristic to decide *what* to
# remove — long-lived branches (e.g. `website`, the `ci` line) are merged
# into main too, so auto-detection would happily delete them. Naming the
# target is the safety.
#
# Safety still comes from git's own refusals, not from cleverness here:
#   - the worktree won't be removed if it has uncommitted/untracked changes
#     (no `--force`);
#   - the local branch is deleted ONLY if it is fully merged into
#     `origin/main` — otherwise the worktree goes but the branch (and its
#     unmerged commits) is kept.
#
# USAGE
#   scripts/wt-rm.sh <branch>
#   scripts/wt-rm.sh feat/clause-concept-hints
#
# For a worktree whose directory you already deleted by hand, use the
# built-in `git worktree prune` (it only clears bookkeeping — never a
# directory or a branch).

set -euo pipefail

log() { printf '  wt-rm: %s\n' "$*" >&2; }
die() { printf 'wt-rm: ERROR: %s\n' "$*" >&2; exit 1; }

[ $# -eq 1 ] || die "usage: wt-rm.sh <branch>"
branch="$1"

git rev-parse --git-dir >/dev/null 2>&1 || die "not inside a git repo"

# Resolve the named branch to its worktree path.
path=""; cur=""
while read -r key val; do
  case "$key" in
    worktree) cur="$val" ;;
    branch)   [ "${val#refs/heads/}" = "$branch" ] && path="$cur" ;;
  esac
done < <(git worktree list --porcelain)

[ -n "$path" ] || die "no worktree is checked out on branch '$branch' (see: git worktree list)"

main_wt="$(git worktree list --porcelain | awk '/^worktree /{print $2; exit}')"
here="$(git rev-parse --show-toplevel)"
[ "$path" != "$main_wt" ] || die "refusing to remove the primary checkout ($path)"
[ "$path" != "$here" ]    || die "refusing to remove the worktree you're standing in — run this from elsewhere"

log "removing worktree $path (branch $branch)"
git worktree remove "$path" \
  || die "could not remove $path — it likely has uncommitted or untracked changes; clean it (or remove by hand) first"

# Delete the local branch only if it is safely merged into origin/main;
# otherwise keep it so unmerged commits are never lost. (No auto-fetch — it
# judges against your current origin/main; run `git fetch` first if you want
# a freshly-merged branch to be eligible.)
if git rev-parse --verify --quiet origin/main >/dev/null \
   && git merge-base --is-ancestor "$branch" origin/main; then
  git branch -D "$branch" >/dev/null
  log "deleted local branch $branch (merged into origin/main)"
else
  log "kept local branch $branch — not merged into origin/main; delete with 'git branch -D $branch' if you're sure"
fi

log "done"