#!/usr/bin/env bash
# git-worktrees-branches-agent-sessions.sh — one worktree and one branch per agent task.
#
# What it does:
#   new <task>   creates .worktrees/<task> on a new branch agent/<task> from the current HEAD,
#                copies any gitignored files listed in .worktreeinclude (one path per line,
#                same idea as Claude Code's .worktreeinclude) into it, and prints the commands
#                to start an agent there.
#   list         shows every worktree and whether it has uncommitted changes.
#   clean        removes worktrees under .worktrees/ that are clean (no changes, no untracked
#                files) and lists the ones it kept because they still hold work.
#
# Run from the main checkout:  bash git-worktrees-branches-agent-sessions.sh new fix-parser
# Requires git 2.5+ (worktree support). Tested with bash on Windows (Git Bash) and Linux.
set -euo pipefail

ROOT="$(git rev-parse --show-toplevel 2>/dev/null)" || { echo "not inside a git repository" >&2; exit 2; }
WT_DIR="$ROOT/.worktrees"

usage() { sed -n '2,15p' "$0"; exit 2; }

cmd_new() {
  local task="${1:-}"; [[ -n "$task" ]] || usage
  local path="$WT_DIR/$task" branch="agent/$task"
  mkdir -p "$WT_DIR"
  grep -qx '.worktrees/' "$ROOT/.gitignore" 2>/dev/null || echo '.worktrees/' >> "$ROOT/.gitignore"
  git -C "$ROOT" worktree add -b "$branch" "$path" HEAD
  if [[ -f "$ROOT/.worktreeinclude" ]]; then
    while IFS= read -r rel; do
      [[ -z "$rel" || "$rel" == \#* ]] && continue
      if [[ -e "$ROOT/$rel" ]] && git -C "$ROOT" check-ignore -q "$rel"; then
        mkdir -p "$path/$(dirname "$rel")"
        cp -r "$ROOT/$rel" "$path/$rel"
        echo "seeded $rel"
      fi
    done < "$ROOT/.worktreeinclude"
  fi
  echo
  echo "worktree ready: $path  (branch $branch)"
  echo "start an agent there with one of:"
  echo "  cd \"$path\" && claude"
  echo "  cd \"$path\" && codex --sandbox workspace-write"
  echo "when it is green, review the diff from the main checkout:"
  echo "  git diff HEAD...$branch"
}

cmd_list() {
  git -C "$ROOT" worktree list --porcelain | awk '/^worktree /{print $2}' | while read -r wt; do
    local status
    status="$(git -C "$wt" status --porcelain 2>/dev/null | wc -l | tr -d ' ')"
    local branch
    branch="$(git -C "$wt" rev-parse --abbrev-ref HEAD 2>/dev/null)"
    printf '%-8s %-24s %s\n' "$([[ "$status" == 0 ]] && echo clean || echo "dirty($status)")" "$branch" "$wt"
  done
}

cmd_clean() {
  local kept=0 removed=0
  [[ -d "$WT_DIR" ]] || { echo "no .worktrees/ directory"; return 0; }
  for wt in "$WT_DIR"/*/; do
    [[ -d "$wt" ]] || continue
    wt="${wt%/}"
    if [[ -n "$(git -C "$wt" status --porcelain 2>/dev/null)" ]]; then
      echo "kept   $wt (uncommitted changes or untracked files)"
      kept=$((kept + 1))
    else
      git -C "$ROOT" worktree remove "$wt"
      echo "removed $wt"
      removed=$((removed + 1))
    fi
  done
  git -C "$ROOT" worktree prune
  echo "removed $removed, kept $kept; branches were left in place (delete with: git branch -d agent/<task>)"
}

case "${1:-}" in
  new)   shift; cmd_new "$@" ;;
  list)  cmd_list ;;
  clean) cmd_clean ;;
  *)     usage ;;
esac