#!/bin/bash

# Configuration (Customize these!)
REPO_URL="ssh://gitea@git.orca-central.de:10229/jali/PDP10Sudoku.git"
REPO_LOCAL_PATH="/home/jali/Projects/PDP10Sudoku"
BRANCH_NAME="develop"
POLL_INTERVAL=60  # Seconds between checks
#LOG_FILE="/var/log/git-monitor.log" # Log file for recording actions
LOCK_FILE="/tmp/git-monitor.lock" # File to prevent multiple instances running concurrently

# Functions
log_message() {
  local level=$1
  local message=$2
  timestamp=$(date +'%Y-%m-%d %H:%M:%S')
  #echo "$timestamp [$level] $message" >> "$LOG_FILE"
  echo "$timestamp [$level] $message"  # Also print to console (optional)
}

check_lock() {
  if [ -f "$LOCK_FILE" ]; then
    log_message "WARN" "Another instance is already running. Exiting."
    exit 1
  fi
}

create_lock() {
  touch "$LOCK_FILE"
}

remove_lock() {
  rm -f "$LOCK_FILE"
}

initialize_repo() {
  if [ ! -d "$REPO_LOCAL_PATH" ]; then
    log_message "INFO" "Repository directory does not exist. Cloning..."
    mkdir -p "$REPO_LOCAL_PATH"
    git clone --depth 1 "$REPO_URL" "$REPO_LOCAL_PATH"
    if [ $? -ne 0 ]; then
      log_message "ERROR" "Failed to clone repository. Exiting."
      exit 1
    fi
    log_message "INFO" "Repository cloned successfully."
  fi
}

check_for_updates() {
  local last_commit_hash
  local current_commit_hash

  # Get the last known commit hash (from a file)
  if [ -f "$REPO_LOCAL_PATH/.git-monitor-last-commit" ]; then
    last_commit_hash=$(cat "$REPO_LOCAL_PATH/.git-monitor-last-commit")
  else
    last_commit_hash="" # Initialize if file doesn't exist
  fi

  # Fetch the latest commit hash from the remote repository
  current_commit_hash=$(git -C "$REPO_LOCAL_PATH" branch --format '%(sha)')

  if [ -z "$last_commit_hash" ] || [ "$current_commit_hash" != "$last_commit_hash" ]; then
    log_message "INFO" "New commits detected. Pulling..."
    git -C "$REPO_LOCAL_PATH" pull origin "$BRANCH_NAME"
    if [ $? -eq 0 ]; then
      log_message "INFO" "Pull successful."

      # Update the last commit hash file
      echo "$current_commit_hash" > "$REPO_LOCAL_PATH/.git-monitor-last-commit"
    else
      log_message "ERROR" "Pull failed."
    fi
  fi
}

# Main Execution
check_lock
create_lock

log_message "INFO" "Git monitor started."

initialize_repo

while true; do
  check_for_updates
  sleep "$POLL_INTERVAL"
done

remove_lock # This won't be reached in this infinite loop.  Useful if exiting gracefully.