#!/usr/bin/env python

import os
import logging
import logging.handlers

BASE_LOGGER_NAME = "splunk.splgen"
DEFAULT_LEVEL = logging.INFO

def get_splunkhome_path():
    return os.path.normpath(os.environ["SPLUNK_HOME"])


def make_splunkhome_path(p):
    return os.path.join(get_splunkhome_path(), *p)


def get_logger(name=BASE_LOGGER_NAME, level=DEFAULT_LEVEL):
    """Returns a general-purpose logger instance.

    The logger is configured to write to both:
      * A (rotated) file in $SPLUNK_HOME/var/log/splunk/<name>.log
      * Standard error.

    Additionally, it consults $SPLUNK_HOME/etc/log.cfg and
    log-local.cfg for default log-levels. You can configure per-logger
    log-levels by adding a property to log-local.cfg that looks like:

        [python]
        myloggername = DEBUG

    For DEBUG messages to show up in search.log as well, you will need
    to modify $SPLUNK_HOME/etc/log-searchprocess-local.cfg to contain:

        category.ChunkedExternProcessor=DEBUG

    Idiomatic usage is:

        #!/usr/bin/env python
        import setup_logging
        logger = setup_logging.get_logger()

        def foo():
            logger.warn("Red Alert, report to battle stations")

    """
    logger = logging.getLogger(name)

    # Initial setup
    if len(logger.handlers) == 0:
        logger.setLevel(level)

        has_splunk_home = os.environ.get("SPLUNK_HOME")
        if has_splunk_home:
            path = make_splunkhome_path(["var", "log", "splunk", name + ".log"])
            backup_count = 5
        else:
            # No backups if logging to current directory
            path = os.path.normpath(os.path.join(os.getcwd(), name + ".log"))
            backup_count = 0

        file_handler = logging.handlers.RotatingFileHandler(
            path, maxBytes=1000000, backupCount=backup_count
        )
        formatter = logging.Formatter(
            "%(created)f PID %(process)d %(asctime)s %(levelname)s [%(name)s] [%(funcName)s] %(message)s"
        )
        file_handler.setFormatter(formatter)
        logger.addHandler(file_handler)

        stream_handler = logging.StreamHandler()
        stream_handler.setFormatter(logging.Formatter("%(levelname)s %(message)s"))
        logger.addHandler(stream_handler)

        if has_splunk_home:
            try:
                import splunk

                # Read logging level information from log.cfg so it will overwrite log
                # Note if logger level is specified on that file then it will overwrite log level
                SPLUNK_HOME = os.environ["SPLUNK_HOME"]

                LOGGING_DEFAULT_CONFIG_FILE = os.path.join(
                    SPLUNK_HOME, "etc", "log.cfg"
                )
                LOGGING_LOCAL_CONFIG_FILE = os.path.join(
                    SPLUNK_HOME, "etc", "log-local.cfg"
                )
                LOGGING_STANZA_NAME = "python"
                splunk.setupSplunkLogger(
                    logger,
                    LOGGING_DEFAULT_CONFIG_FILE,
                    LOGGING_LOCAL_CONFIG_FILE,
                    LOGGING_STANZA_NAME,
                    verbose=False,
                )
            except ImportError:
                warning_msg = "Unable to import splunk python module: cannot setup splunk logging. "
                logger.warn(warning_msg)

    return logger


def get_child_logger(name=None):
    """Returns a logger for internal messages."""
    logger = get_logger()
    if name:
        return logger.getChild(name)
    else:
        return logger