#!/usr/bin/env python
# PipelineSelection.py
#   Copyright (C) 2006 CCLRC, Graeme Winter
#
#   This code is distributed under the BSD license, a copy of which is
#   included in the root directory of this package.
#
# A handler to manage the selection of pipelines through which to run xia2,
# for instance what indexer to use, what integrater and what scaler.
# This will look for a file preferences.xia in ~/.xia2 or equivalent,
# and the current working directory.

import os
import sys

def check(key, value):
  '''Check that this thing is allowed to have this value.'''

  # this should be current!

  allowed_indexers = [
      'mosflm', 'labelit', 'labelitii', 'xds', 'xdsii', 'xdssum', 'dials']
  allowed_integraters = ['mosflmr', 'xdsr', 'mosflm', 'xds', 'dials']
  allowed_scalers = ['ccp4a', 'xdsa']

  if key == 'indexer':
    if not value in allowed_indexers:
      raise RuntimeError, 'indexer %s unknown' % value
    return value

  if key == 'integrater':
    if not value in allowed_integraters:
      raise RuntimeError, 'integrater %s unknown' % value
    if value == 'mosflm':
      return 'mosflmr'
    if value == 'xds':
      return 'xdsr'
    return value

  if key == 'scaler':
    if not value in allowed_scalers:
      raise RuntimeError, 'scaler %s unknown' % value
    return value

  return

preferences = { }

def get_preferences():
  global preferences

  if preferences == { }:
    search_for_preferences()

  return preferences

def add_preference(key, value):
  '''Add in run-time a preference.'''

  global preferences

  value = check(key, value)

  if preferences.has_key(key):
    if preferences[key] != value:
      raise RuntimeError, 'setting %s to %s: already %s' % \
            (key, value, preferences[key])

  preferences[key] = value

  return

def search_for_preferences():
  '''Search for a preferences file, first in HOME then here.'''

  global preferences

  if os.name == 'nt':
    homedir = os.path.join(os.environ['HOMEDRIVE'],
                           os.environ['HOMEPATH'])
    xia2dir = os.path.join(homedir, 'xia2')
  else:
    homedir = os.environ['HOME']
    xia2dir = os.path.join(homedir, '.xia2')

  if os.path.exists(os.path.join(xia2dir, 'preferences.xia')):
    preferences = parse_preferences(
        os.path.join(xia2dir, 'preferences.xia'), preferences)

  # look also in current working directory

  if os.path.exists(os.path.join(os.getcwd(), 'preferences.xia')):
    preferences = parse_preferences(
        os.path.join(os.getcwd(), 'preferences.xia'), preferences)

  return preferences

def parse_preferences(file, preferences):
  '''Parse preferences to the dictionary.'''

  for line in open(file, 'r').readlines():

    # all lower case
    line = line.lower()

    # ignore comment lines
    if line[0] == '!' or line[0] == '#' or not line.split():
      continue

    key = line.split(':')[0].strip()
    value = line.split(':')[1].strip()

    value = check(key, value)

    add_preference(key, value)

  return preferences

if __name__== '__main__':

  print search_for_preferences()