import os
import datetime
import subprocess
import logging
import sys
import boto3
from botocore.exceptions import ClientError
from email_utils import send_email
from gzip_util import gzip_file
import json # For reading JSON config


# Initialize a message list
email_body_parts = []
BACKUP_DIR = "/var/www/apps/db-backup-script/backups" # Example default
MYSQLDUMP_PATH = "/usr/bin/mysqldump" # Example default
LOG_DIR = "/var/www/apps/db-backup-script/logs"
LOG_FILE = "/var/www/apps/db-backup-script/logs/mysql_backup.log"


# Assuming your JSON file is named 'config.json' and is in the same directory
CONFIG_FILE_PATH = 'config.json'

def load_config(file_path):
    with open(file_path, 'r') as f:
        return json.load(f)
    
def set_platform_specific_paths(config):
    # Determine OS and set paths accordingly
    if sys.platform.startswith('win'):
        # Paths for Windows
        # You can also load these from .env if you prefer fine-grained control
        BACKUP_DIR = config['WINDOWS_PATHS']['BACKUP_DIR'] # Default if not in .env
        MYSQLDUMP_PATH = config['WINDOWS_PATHS']['MYSQLDUMP_PATH']
        LOG_DIR = config['WINDOWS_PATHS']['LOG_DIR']
        LOG_FILE = config['WINDOWS_PATHS']['LOG_FILE']
    else:
        if 'LINUX_PATHS' in config:
            # Paths for Ubuntu/Linux
            BACKUP_DIR = config['LINUX_PATHS']['BACKUP_DIR']
            MYSQLDUMP_PATH = config['LINUX_PATHS']['MYSQLDUMP_PATH']
            LOG_DIR = config['LINUX_PATHS']['LOG_DIR']
            LOG_FILE = config['LINUX_PATHS']['LOG_FILE']
        else:
            print("Error: Linux paths not configured in JSON.")
            # Handle this error appropriately, e.g., exit or use default Linux paths.
            BACKUP_DIR = "/var/www/apps/db-backup-script/backups" # Example default
            MYSQLDUMP_PATH = "/usr/bin/mysqldump" # Example default
            LOG_DIR = "/var/www/apps/db-backup-script/logs"
            LOG_FILE = "/var/www/apps/db-backup-script/logs/mysql_backup.log"

    try:
        os.makedirs(BACKUP_DIR, exist_ok=True)
        logging.info(f"Ensured backup directory exists: {BACKUP_DIR}")
        os.makedirs(LOG_DIR, exist_ok=True)
        logging.info(f"Ensured log directory exists: {LOG_DIR}")
    except Exception as ex:
        logging.critical(f"---Unable to create required folders. Database Backup Process Failed: {ex} ---")
        exit(1)

# --- Logging Setup ---
# Configure logging to write messages to a file and to the console
logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s - %(levelname)s - %(message)s',
    handlers=[
        logging.FileHandler(LOG_FILE),
        logging.StreamHandler()
    ]
)

# --- Helper Functions (unchanged from previous version) ---

def build_path(database_name):
    timestamp = datetime.datetime.now().strftime('%Y%m%d%H%M%S')
    backup_filename = f"{timestamp}-{database_name}-database-backup.sql"
    backup_path = os.path.join(BACKUP_DIR, backup_filename)
    return backup_path

def build_mysqldump_command(db_conf):
    command = [
        MYSQLDUMP_PATH,
        f"-h{db_conf["DB_HOST"]}",
        f"-u{db_conf["DB_USER"]}",
        f"-p{db_conf["DB_PASSWORD"]}",
        db_conf["DB_NAME"]
    ]
    return command


def clean_backup_folder():
    folder_path = BACKUP_DIR
    for filename in os.listdir(folder_path):
        file_path = os.path.join(folder_path, filename)
        if os.path.isfile(file_path):
            os.remove(file_path)

def start_backup(db_conf):
    backup_file_path = build_path(db_conf["DB_NAME"])
    command = build_mysqldump_command(db_conf)
    try:
        logging.info(f"Starting backup for database: {db_conf["DB_NAME"]} to {backup_file_path}")
        with open(backup_file_path, "w", encoding="utf-8") as out_file:
            subprocess.run(command, stdout=out_file, check=True, text=True)
        logging.info(f"Successfully backed up {db_conf["DB_NAME"]}.")

        # Compress and delete original
        gzipped_path = gzip_file(backup_file_path, delete_original=True)

        email_body_parts.append(f"Successfully backed up {db_conf["DB_NAME"]}.")
        #return backup_file_path
        return gzipped_path
    except subprocess.CalledProcessError as e:
        logging.error(f"MySQL dump failed for {db_conf["DB_NAME"]}: {e}")
        logging.error(f"Command: {' '.join(e.cmd)}")
        email_body_parts.append(f"MySQL dump failed for {db_conf["DB_NAME"]}: {e}")
        if e.stderr:
            logging.error(f"Stderr: {e.stderr}")
        return None
    except FileNotFoundError:
        logging.error(f"Error: mysqldump not found at '{MYSQLDUMP_PATH}'. Please verify the path.")
        if sys.platform.startswith('win'):
            logging.error(r"On Windows, ensure MySQL is installed and 'mysqldump.exe' path is correct (e.g., C:\Program Files\MySQL\MySQL Server 8.0\bin\mysqldump.exe)")
        else:
            logging.error("On Ubuntu/Linux, you might need to install 'mysql-client' package: sudo apt install mysql-client")
        return None
    except Exception as e:
        logging.error(f"An unexpected error occurred during backup of {db_conf["DB_NAME"]}: {e}")
        return None

def upload_to_git():
    original_cwd = os.getcwd()
    GIT_EXECUTABLE = "git"
    try:
        logging.info(f"Changing directory to {BACKUP_DIR} for Git operations.")
        os.chdir(BACKUP_DIR)

        logging.info("Staging all changes in Git repository...")
        subprocess.run([GIT_EXECUTABLE, "add", "."], check=True, text=True)
        commit_message = f"Automated database backup commit on {datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S')}"
        logging.info(f"Committing changes with message: '{commit_message}'")
        subprocess.run([GIT_EXECUTABLE, "commit", "-m", commit_message], check=True, text=True)
        logging.info("Pushing changes to remote Git repository...")
        subprocess.run([GIT_EXECUTABLE, "push"], check=True, text=True)

        logging.info("Backup files successfully pushed to Git repository.")
    except subprocess.CalledProcessError as e:
        logging.error(f"Git upload failed: {e}")
        logging.error(f"Command: {' '.join(e.cmd)}")
        if e.stderr:
            logging.error(f"Stderr: {e.stderr}")
        raise
    except FileNotFoundError:
        logging.error(f"Error: Git executable ('{GIT_EXECUTABLE}') not found. Ensure Git is installed and in your system's PATH.")
        raise
    except Exception as e:
        logging.error(f"An unexpected error occurred during Git upload: {e}")
        raise
    finally:
        os.chdir(original_cwd)

def remove_before_first_dash(input_string):
    """
    Removes the part of a string before the first dash.

    Args:
        input_string: The string to process.

    Returns:
        The part of the string after the first dash, or the original string
        if no dash is found.
    """
    parts = input_string.split('-', 1)  # Split only at the first dash
    if len(parts) > 1:
        return parts[1]
    else:
        return input_string
    
def upload_to_s3(aws_s3_configuration, file_paths):
    if not file_paths:
        logging.info("No backup files to upload to S3.")
        return

    # Basic validation for S3 configuration
    if not all([aws_s3_configuration["S3_BUCKET_NAME"], aws_s3_configuration["S3_REGION"], aws_s3_configuration["ACCESS_KEY"], aws_s3_configuration["SECRET_KEY"]]):
        logging.error("S3_BUCKET_NAME, S3_REGION, ACCESS_KEY or SECRET_KEY is not set. Cannot upload to S3. Please check your .env file.")
        email_body_parts.append(f"S3_BUCKET_NAME, S3_REGION, ACCESS_KEY or SECRET_KEY is not set. Cannot upload to S3. Please check your .env file.")

        return

    try:
        logging.info(f"Attempting to connect to AWS S3 bucket: {aws_s3_configuration["S3_BUCKET_NAME"]} in region: {aws_s3_configuration["S3_REGION"]}")
        s3_client = boto3.client('s3',
                                  region_name=aws_s3_configuration["S3_REGION"],
                                  aws_access_key_id=aws_s3_configuration["ACCESS_KEY"],
                                  aws_secret_access_key=aws_s3_configuration["SECRET_KEY"])

        for file_path in file_paths:
            if not os.path.exists(file_path):
                logging.warning(f"File not found, skipping S3 upload: {file_path}")
                continue

            s3_object_key = os.path.basename(file_path)
            s3_object_key = remove_before_first_dash(s3_object_key)
            try:
                logging.info(f"Uploading {s3_object_key} to s3://{aws_s3_configuration["S3_BUCKET_NAME"]}/{s3_object_key}")
                s3_client.upload_file(
                    file_path, 
                    aws_s3_configuration["S3_BUCKET_NAME"], 
                    s3_object_key,
                    ExtraArgs={
                        'StorageClass': 'GLACIER_IR',  # Glacier Instant Retrieval
                        'ServerSideEncryption': 'AES256'
                    })
                logging.info(f"Uploaded to {aws_s3_configuration["S3_BUCKET_NAME"]}/{s3_object_key} with Glacier Instant Retrieval")
                email_body_parts.append(f"Successfully uploaded {s3_object_key} to S3.")

            except ClientError as ce:
                logging.error(f"Failed to upload {s3_object_key} to S3: {ce}")
                email_body_parts.append("Failed to upload {s3_object_key} to S3: {ce}")

                if ce.response['Error']['Code'] == 'AccessDenied':
                    logging.error("S3 upload access denied. Check your AWS credentials and bucket policy.")
                    email_body_parts.append("S3 upload access denied. Check your AWS credentials and bucket policy.")
                elif ce.response['Error']['Code'] == 'NoSuchBucket':
                    logging.error(f"S3 bucket '{aws_s3_configuration["S3_BUCKET_NAME"]}' does not exist or you don't have access.")
                    email_body_parts.append(f"S3 bucket '{aws_s3_configuration["S3_BUCKET_NAME"]}' does not exist or you don't have access.")

                else:
                    logging.error(f"S3 ClientError details: {ce.response['Error']['Code']} - {ce.response['Error']['Message']}")
                    email_body_parts.append(f"S3 ClientError details: {ce.response['Error']['Code']} - {ce.response['Error']['Message']}")

            except Exception as e:
                logging.error(f"An unexpected error occurred during S3 upload of {s3_object_key}: {e}")
        logging.info("All S3 uploads attempted.")
    except Exception as e:
        logging.critical(f"Failed to initialize S3 client or a critical S3 error occurred: {e}")
        email_body_parts.append(f"Failed to initialize S3 client or a critical S3 error occurred: {e}")



# --- Main Execution (unchanged from previous version) ---
if __name__ == "__main__":
    logging.info("--- Database Backup Process Started ---")
    backup_files_created = []

    config = load_config(CONFIG_FILE_PATH)
    set_platform_specific_paths(config)

    clean_backup_folder()

    # You would then loop through db_configs and perform backups as in the previous example
    db_configs = config['DATABASE_CONFIGS']
    email_body_parts.append(f"Starting backup for database")
    email_body_parts.append(f"-------------------------------------------------------------")

    for db_conf in db_configs:
        print( db_conf)
        # Basic validation that essential DB connection variables are loaded
        if not all([db_conf["DB_HOST"], db_conf["DB_USER"], db_conf["DB_PASSWORD"]]):
            logging.critical("Missing essential database connection variables. Please check your .env file.")
            continue

        email_body_parts.append(f"Starting backup for database: {db_conf["DB_NAME"]}")
        file_path = start_backup(db_conf)
        if file_path:
            backup_files_created.append(file_path)
        
        email_body_parts.append(f"")


    try:
       
        email_body_parts.append(f"Starting Git upload process...")
        email_body_parts.append(f"-------------------------------------------------------------")

        do_upload_to_git = config['ACTIONS']['DO_UPLOAD_TO_GIT']
        if do_upload_to_git:
            logging.info("Starting Git upload process...")            
            upload_to_git()
        else:
            logging.info("Disabled Git upload process...")
            email_body_parts.append(f"Disabled Git upload process...")

        email_body_parts.append(f"<br>Starting S3 upload process... ")
        email_body_parts.append(f"-------------------------------------------------------------")


        do_upload_to_s3 = config['ACTIONS']['DO_UPLOAD_TO_S3']
        if do_upload_to_s3:
            logging.info("Starting S3 upload process...")
            aws_s3_configuration = config['AWS_S3_CONFIGURATION']
            upload_to_s3(aws_s3_configuration, backup_files_created)
        else:
            logging.info("Disabled S3 upload process...")
            email_body_parts.append(f"Disabled S3 upload process...")


        # Send HTML email to multiple recipients
        # Final stage: send the mail
        do_send_email = config['ACTIONS']['DO_SEND_EMAIL']
        if do_send_email :
            email_body_parts.append(f"<br><br>Backup completed for folloing files:")  
            email_body_parts.append(f"-------------------------------------------------------------")
   
            for file_name in backup_files_created:
                email_body_parts.append(f"{file_name}")  

            email_body_parts.append(f"<br><br><br>Starting sending mail")
            email_body ="<br>".join(email_body_parts)  # for plain text
            email_config = config['EMAIL_CONFIGURATION']
            if email_config["EMAIL_RECEIVERS"]:
                # Split the string by the comma delimiter
                email_receivers_array = [item.strip() for item in email_config["EMAIL_RECEIVERS"].split(',')]
                if email_config["EMAIL_SUBJECT"] and email_config["EMAIL_SUBJECT"].strip(): # Check if not None and not just whitespace
                    email_subject = email_config["EMAIL_SUBJECT"].strip()
                else:
                    email_subject = "Database backup process"
                    
                send_email(
                    email_config["EMAIL_HOST"], email_config["EMAIL_PORT"], email_config["EMAIL_USER"], email_config["EMAIL_PASS"],
                    subject=email_subject,
                    body=email_body,
                    to_emails=email_receivers_array,
                    html=True                
                )
                logging.info(f"Send Mail to:  {email_receivers_array}")
            else:
                logging.info(f"database list array (DB_LIST_TO_BACKUP) not found or is empty.")        
        else:
            logging.info("Disabled EMAIL send process...")
            email_body_parts.append(f"Disabled EMAIL send process...")

        logging.info("--- Database Backup Process Completed Successfully ---")


        exit(0)

    except Exception as ex:
        logging.critical(f"--- Database Backup Process Failed: {ex} ---")
        exit(1)