#!/usr/bin/env ruby
# encoding: UTF-8

# (c) Copyright 2014 Hewlett-Packard Development Company, L.P.
#
#    Licensed under the Apache License, Version 2.0 (the "License");
#    you may not use this file except in compliance with the License.
#    You may obtain a copy of the License at
#
#        http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS,
#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#    See the License for the specific language governing permissions and
#    limitations under the License.

# create a forj.log file in ~/.hpcloud/forj.log

require 'rubygems'
require 'logger'
require 'ansi'
require 'ansi/logger'

#
module PrcLib
  # Class used to create 2 logger object, in order to keep track of error in a
  # log file and change log output to OUTPUT on needs (option flags).
  # The idea is that everytime, if you did not set the debug level mode, you can
  # refer to the log file which is
  # already configured with Logger::DEBUG level.
  #
  # As well, sometimes, you do not want to keep track on messages that are just
  # to keep informed the end user about activity.
  # So, this object implement 2 Logger objects.
  # * One for log file
  # * One for print out.
  #
  # Everytime you log a message with Logging, it is printed out if the level
  # permits and stored everytime in the log file, never mind about Logger level
  # set.
  # In several cases, messages are printed out, but not stored in the log file.
  #
  # To use the Prc::Logging system, do the following:
  #    require 'PrcLib'
  #
  #    # To configure logging system:
  #    PrcLib.app_name = 'config/app' # Define application data path as
  #                                   # ~/.<app_name>.
  #                                   #  Ex: 'config/app' will use ~/.config/app
  #    PrcLib.log_file = 'app.log'    # Relative path to the log file name
  #                                   # stored in the Application data path.
  #                                   # Here, ~/.config/app/app.log
  #    PrcLib.level = Logger::FATAL   # Define printout debug level. Can be any
  #                                   # Logger predefined value.
  #
  #    # To log some information:
  #    PrcLib.debug('My %s debug message', 'test')
  #    PrcLib.info('My info message')
  #    PrcLib.warning('my warning')
  #    PrcLib.error('my error')
  #    PrcLib.fatal(2, "Fatal error, with return code = 2)
  #    PrcLib.message('Only printout message')
  #
  #    # You can printout some instant message to the terminal, not logged.
  #    # This is useful before any action that will take time to be executed.
  #    # It is inform the end user that something is still running, which means
  #    # the application is not frozen
  #    PrcLib.state("Running a long task")
  #    # The next message will replace the previous state message.
  #    sleep(10)
  #    PrcLib.info("The long task has been executed successfully.")
  #
  #    # You can change the logger level with PrcLib.level
  #    PrcLib.level = Logger::DEBUG
  #
  #    # You can just print high level message (print without \n)
  #    # if PrcLib.level is not DEBUG or INFO.
  #    PrcLib.high_level_msg("Print a message, not logged, if level is not DEBUG
  #    # or INFO")
  #
  # For details, see Logging functions
  #
  class Logging
    # Initialize Logging instance
    # The log file name is defined by PrcLib.log_file
    # The log path is defined by PrcLib.app_name and will be kept as
    # ~/.<PrcLib.app_name>
    # The log level is defined by PrcLib.level. It will update only log print
    # out.
    # Depending on levels, messages are prefixed by colored 'ERROR!!!',
    # 'FATAL!!!', 'WARNING' or <LEVEL NAME>
    def initialize
      file_logger_initialize

      @out_logger = Logger.new(STDOUT)
      @level = Logger::WARN
      @out_logger.level = @level
      @out_logger.formatter = proc do |severity, _datetime, _progname, msg|
        case severity
        when 'ANY'
          str = "#{msg} \n"
        when 'ERROR', 'FATAL'
          str = ANSI.bold(ANSI.red("#{severity}!!!")) + ": #{msg} \n"
        when 'WARN'
          str = ANSI.bold(ANSI.yellow('WARNING')) + ": #{msg} \n"
        else
          str = "#{severity}: #{msg} \n"
        end
        str
      end
    end

    # Is Logging print out level is info?
    def info?
      (@out_logger.info?)
    end

    # Is Logging print out level is debug?
    def debug?
      (@out_logger.debug?)
    end

    # Is Logging print out level is error?
    def error?
      (@out_logger.error?)
    end

    # Is Logging print out level is fatal?
    def fatal?
      (@out_logger.fatal?)
    end

    # Log to STDOUT and Log file and INFO class message
    def info(message)
      @out_logger.info(message + ANSI.clear_eol)
      @file_logger.info(message)
    end

    # Log to STDOUT and Log file and DEBUG class message
    def debug(message)
      @out_logger.debug(message + ANSI.clear_eol)
      @file_logger.debug(message)
    end

    # Log to STDOUT and Log file and ERROR class message
    def error(message)
      @out_logger.error(message + ANSI.clear_eol)
      @file_logger.error(message + "\n" + caller.join("\n"))
    end

    # Log to STDOUT and Log file and FATAL class message
    def fatal(message)
      @out_logger.fatal(message + ANSI.clear_eol)
      @file_logger.fatal(message)
    end

    # Log to STDOUT and Log file and WARNING class message
    def warn(message)
      @out_logger.warn(message + ANSI.clear_eol)
      @file_logger.warn(message)
    end

    # set STDOUT logger level
    def level=(level)
      @level = level
      @out_logger.level = level
    end

    attr_reader :level

    # Print out a message, not logged in the log file. This message is printed
    # out systematically as not taking care of logger level.
    def unknown(message)
      @out_logger.unknown(message + ANSI.clear_eol)
    end

    private

    def file_logger_initialize
      @file_logger = Logger.new(PrcLib.log_file, 'weekly')
      @file_logger.level = Logger::DEBUG
      @file_logger.formatter = proc do |severity, datetime, progname, msg|
        "#{progname} : #{datetime}: #{severity}: #{msg} \n"
      end
    end
  end

  module_function

  # Create a Logging object if missing and return it.
  # Used internally by other functions
  def log_object
    PrcLib.log = PrcLib::Logging.new if PrcLib.log.nil?
    PrcLib.log
  end

  def log_object=(logger)
    return PrcLib.log unless logger.is_a?(Logger)

    PrcLib.log = logger if PrcLib.log.nil?
    PrcLib.log
  end

  # Print out a message, not logged in the log file. This message is printed out
  # systematically as not taking care of logger level.
  def message(message, *p)
    log_object.unknown(format(message, *p))
  end

  # Log to STDOUT and Log file and INFO class message
  def info(message, *p)
    log_object.info(format(message, *p))
    nil
  end

  # Log to STDOUT and Log file and DEBUG class message
  def debug(message, *p)
    log_object.debug(format(message, *p))
    nil
  end

  # Log to STDOUT and Log file and WARNING class message
  def warning(message, *p)
    log_object.warn(format(message, *p))
    nil
  end

  # Log to STDOUT and Log file and ERROR class message
  def error(message, *p)
    log_object.error(format(message, *p))
    nil
  end

  # Internal heap management to help controller developper to identify issue.
  def dcl_fail(msg, *p)
    msg = "Declaration error:\n" + msg
    msg += format("\nSee at %s",
                  PrcLib.model.heap[0]) if PrcLib.model.heap.is_a?(Array)
    runtime_fail(msg, *p)
  end

  # fail extended with format.
  def runtime_fail(msg, *p)
    fail Lorj::PrcError.new, format(msg, *p)
  end

  # Log to STDOUT and Log file and FATAL class message then exit the application
  # with a return code.
  # fatal retrieve the caller list of functions and save it to the log file if
  # the exception class is given.
  # The exception class should provide message and backtrace.
  def fatal(rc, message, *p)
    if p.length > 0 && p[-1].is_a?(Exception)
      e = p[-1]
      p.pop
      message = format("%s\n%s\n%s", message, e.message, e.backtrace.join("\n"))
    end
    log_object.fatal(format(message, *p))
    puts format('Issues found. Please fix it and retry. Process aborted. '\
         "See details in log file '%s'.", PrcLib.log_file)
    exit rc
  end

  def level=(level)
    log_object.level = level
    nil
  end

  def level
    log_object.level
  end

  # Print the message to the same line.
  def state(message, *p)
    print(format("%s%s ...\r", ANSI.clear_line,
                 format(message, *p))) if log_object.level <= Logger::INFO
    nil
  end

  # Not DEBUG and not INFO. Just printed to the output.
  def high_level_msg(message, *p)
    print(format(message, *p)) if log_object.level > 1
    nil
  end
end