"""
Generate header file with macros defining MicroPython version info.

This script works with Python 2.6, 2.7, 3.3 and 3.4.
"""

from __future__ import print_function

import sys
import os
import datetime
import subprocess


def get_version_info_from_git():
 # Python 2.6 doesn't have check_output, so check for that
 try:
 subprocess.check_output
 subprocess.check_call
 except AttributeError:
 return None

 # Note: git describe doesn't work if no tag is available
 try:
 git_tag = subprocess.check_output(
 ["git", "describe", "--dirty", "--always"],
 stderr=subprocess.STDOUT,
 universal_newlines=True,
 ).strip()
 except subprocess.CalledProcessError as er:
 if er.returncode == 128:
 # git exit code of 128 means no repository found
 return None
 git_tag = ""
 except OSError:
 return None
 try:
 git_hash = subprocess.check_output(
 ["git", "rev-parse", "--short", "HEAD"],
 stderr=subprocess.STDOUT,
 universal_newlines=True,
 ).strip()
 except subprocess.CalledProcessError:
 git_hash = "unknown"
 except OSError:
 return None

 try:
 # Check if there are any modified files.
 subprocess.check_call(
 ["git", "diff", "--no-ext-diff", "--quiet", "--exit-code"], stderr=subprocess.STDOUT
 )
 # Check if there are any staged files.
 subprocess.check_call(
 ["git", "diff-index", "--cached", "--quiet", "HEAD", "--"], stderr=subprocess.STDOUT
 )
 except subprocess.CalledProcessError:
 git_hash += "-dirty"
 except OSError:
 return None

 return git_tag, git_hash


def get_version_info_from_docs_conf():
 return ('v0.1.0 for HOS', '<no hash>')


def make_version_header(filename):
 # Get version info using git, with fallback to docs/conf.py
 info = get_version_info_from_git()
 if info is None:
 info = get_version_info_from_docs_conf()
 
 git_tag, git_hash = info

 # Generate the file with the git and version info
 file_data = """\
// This file was generated by py/makeversionhdr.py
#define MICROPY_GIT_TAG "%s"
#define MICROPY_GIT_HASH "%s"
#define MICROPY_BUILD_DATE "%s"
""" % (
 git_tag,
 git_hash,
 datetime.date.today().strftime("%Y-%m-%d"),
 )

 # Check if the file contents changed from last time
 write_file = True
 if os.path.isfile(filename):
 with open(filename, "r") as f:
 existing_data = f.read()
 if existing_data == file_data:
 write_file = False

 # Only write the file if we need to
 if write_file:
 print("GEN %s" % filename)
 with open(filename, "w") as f:
 f.write(file_data)


if __name__ == "__main__":
 make_version_header(sys.argv[1])