#!/usr/bin/env bash
# git-lock-guard: PreToolUse hook that clears stale git index.lock files
# before git write operations.
#
# Claude Code's internal git status polling creates stale lock files that
# persist after the process exits (anthropics/claude-code#11005). This hook
# detects and removes them before LLM-initiated git commands run.
#
# Only acts on git write commands (add, commit, merge, push, etc.).
# Read-only commands (status, log, diff, show) are skipped.
set -uo pipefail

INPUT=$(cat)

# Only act on Bash tool calls
TOOL_NAME=$(echo "$INPUT" | python3 -c "import sys,json; print(json.load(sys.stdin).get('tool_name',''))" 2>/dev/null)
[ "$TOOL_NAME" = "Bash" ] || exit 0

COMMAND=$(echo "$INPUT" | python3 -c "import sys,json; print(json.load(sys.stdin).get('tool_input',{}).get('command',''))" 2>/dev/null)

# Only act on git write commands — skip read-only operations
case "$COMMAND" in
  git\ add*|git\ commit*|git\ merge*|git\ push*|git\ pull*|\
  git\ checkout*|git\ stash*|git\ rebase*|git\ reset*|\
  git\ cherry-pick*|git\ rm*|git\ mv*|git\ fetch*)
    ;;
  *)
    exit 0
    ;;
esac

# Resolve the git directory for the current working directory
CWD=$(echo "$INPUT" | python3 -c "import sys,json; print(json.load(sys.stdin).get('cwd',''))" 2>/dev/null)
[ -n "$CWD" ] || exit 0

# Find the .git directory (handles both regular repos and worktrees)
GIT_DIR=$(git -C "$CWD" rev-parse --git-dir 2>/dev/null) || exit 0

# For worktrees, also check the common git dir (shared index operations)
GIT_COMMON_DIR=$(git -C "$CWD" rev-parse --git-common-dir 2>/dev/null) || GIT_COMMON_DIR="$GIT_DIR"

for DIR in "$GIT_DIR" "$GIT_COMMON_DIR"; do
  LOCK="$DIR/index.lock"
  [ -f "$LOCK" ] || continue

  # Check if any process holds the lock
  if command -v lsof &>/dev/null; then
    if lsof "$LOCK" &>/dev/null; then
      # Lock is held by a live process — don't touch it
      continue
    fi
  elif command -v fuser &>/dev/null; then
    if fuser "$LOCK" &>/dev/null 2>&1; then
      continue
    fi
  fi

  # Stale lock — remove it
  rm -f "$LOCK" 2>/dev/null
done

# Always allow the command to proceed
exit 0