#!/bin/bash
# on-pretooluse-guard.sh — PreToolUse hook: guard destructive operations.
#
# Called by Claude Code before executing a Bash command in agent sessions.
# Blocks:
# - git push --force / -f to primary branch
# - rm -rf targeting paths outside the worktree
# - Direct Codeberg API merge calls (should go through phase protocol)
# - git checkout / git switch to primary branch (stay on feature branch)
#
# Usage (in .claude/settings.json):
#   {"type":"command","command":"this-script <primary_branch> <worktree_path>"}
#
# Args: $1 = primary branch (default: main), $2 = worktree absolute path
#
# Exit 0: allow (tool proceeds)
# Exit 2: deny (reason on stdout — Claude sees it and can self-correct)

primary_branch="${1:-main}"
worktree_path="${2:-}"

input=$(cat)

# Extract the command string from hook JSON
command_str=$(printf '%s' "$input" | jq -r '.tool_input.command // empty' 2>/dev/null)
[ -z "$command_str" ] && exit 0

# --- Guard 1: force push to primary branch ---
if printf '%s' "$command_str" | grep -qE '\bgit\s+push\b' \
   && printf '%s' "$command_str" | grep -qE '(--force|--force-with-lease|\s-[a-zA-Z]*f)\b' \
   && printf '%s' "$command_str" | grep -qw "$primary_branch"; then
  printf 'BLOCKED: Force-pushing to %s is not allowed. Push to your feature branch instead.\n' "$primary_branch"
  exit 2
fi

# --- Guard 2: rm -rf outside worktree ---
if [ -n "$worktree_path" ] \
   && printf '%s' "$command_str" | grep -qE '\brm\s+(-[a-zA-Z]*r[a-zA-Z]*f|-[a-zA-Z]*f[a-zA-Z]*r)\b'; then
  # Extract absolute paths from the command
  abs_paths=$(printf '%s' "$command_str" | grep -oE "/[^[:space:];|&>\"']+" || true)
  if [ -n "$abs_paths" ]; then
    while IFS= read -r p; do
      [ -z "$p" ] && continue
      case "$p" in
        "${worktree_path}"/*|"${worktree_path}") ;;  # Inside worktree — allow
        /dev/*) ;;  # Device paths — allow
        *)
          printf 'BLOCKED: rm -rf targets %s which is outside the worktree (%s). Only delete files within your worktree.\n' "$p" "$worktree_path"
          exit 2
          ;;
      esac
    done <<< "$abs_paths"
  fi
fi

# --- Guard 3: Direct Codeberg API merge calls ---
if printf '%s' "$command_str" | grep -qE '/pulls/[0-9]+/merge'; then
  printf 'BLOCKED: Direct API merge calls must go through the phase protocol. Push your changes and write PHASE:awaiting_ci — the orchestrator handles merges.\n'
  exit 2
fi

# --- Guard 4: checkout/switch to primary branch ---
# Blocks: git checkout main, git switch main
# Allows: git checkout -b branch main, git checkout -- file
if printf '%s' "$command_str" | grep -qE "\bgit\s+(checkout|switch)\s+${primary_branch}\b" \
   && ! printf '%s' "$command_str" | grep -qE '\s--\s'; then
  printf 'BLOCKED: Switching to %s is not allowed. Stay on your feature branch.\n' "$primary_branch"
  exit 2
fi

exit 0