import config.base
import os
import re

class Configure(config.base.Configure):
  def __init__(self, framework):
    config.base.Configure.__init__(self, framework)
    self.headerPrefix = 'PETSC'
    self.substPrefix  = 'PETSC'
    return

  def __str1__(self):
    if not hasattr(self, 'arch'):
      return ''
    desc = ['PETSc:']
    desc.append('  PETSC_ARCH: '+str(self.arch))
    return '\n'.join(desc)+'\n'

  def setupHelp(self, help):
    import nargs
    help.addArgument('PETSc', '-PETSC_ARCH=<string>',     nargs.Arg(None, None, 'The configuration name'))
    help.addArgument('PETSc', '-with-petsc-arch=<string>',nargs.Arg(None, None, 'The configuration name'))
    help.addArgument('PETSc', '-force=<bool>',            nargs.ArgBool(None, 0, 'Bypass configure hash caching, and run to completion'))
    return

  def setupDependencies(self, framework):
    self.sourceControl = framework.require('config.sourceControl',self)
    self.petscdir = framework.require('PETSc.options.petscdir', self)
    return

  def setNativeArchitecture(self):
    import sys
    arch = 'arch-' + sys.platform.replace('cygwin','mswin')
    # use opt/debug, c/c++ tags.s
    arch+= '-'+self.framework.argDB['with-clanguage'].lower().replace('+','x')
    if self.framework.argDB['with-debugging']:
      arch += '-debug'
    else:
      arch += '-opt'
    self.nativeArch = arch
    return

  def configureArchitecture(self):
    '''Checks PETSC_ARCH and sets if not set'''
    # Warn if PETSC_ARCH doesn't match env variable
    if 'PETSC_ARCH' in self.framework.argDB and 'PETSC_ARCH' in os.environ and self.framework.argDB['PETSC_ARCH'] != os.environ['PETSC_ARCH']:
      self.logPrintBox('''\
Warning: PETSC_ARCH from environment does not match command-line or name of script.
Warning: Using from command-line or name of script: %s, ignoring environment: %s''' % (str(self.framework.argDB['PETSC_ARCH']), str(os.environ['PETSC_ARCH'])))
      os.environ['PETSC_ARCH'] = self.framework.argDB['PETSC_ARCH']
    if 'with-petsc-arch' in self.framework.argDB:
      self.arch = self.framework.argDB['with-petsc-arch']
      msg = 'option -with-petsc-arch='+str(self.arch)
    elif 'PETSC_ARCH' in self.framework.argDB:
      self.arch = self.framework.argDB['PETSC_ARCH']
      msg = 'option PETSC_ARCH='+str(self.arch)
    elif 'PETSC_ARCH' in os.environ:
      self.arch = os.environ['PETSC_ARCH']
      msg = 'environment variable PETSC_ARCH='+str(self.arch)
    else:
      self.arch = self.nativeArch
    if self.arch.find('/') >= 0 or self.arch.find('\\') >= 0:
      raise RuntimeError('PETSC_ARCH should not contain path characters, but you have specified with '+msg)
    if self.arch.startswith('-'):
      raise RuntimeError('PETSC_ARCH should not start with "-", but you have specified with '+msg)
    if self.arch.startswith('.'):
      raise RuntimeError('PETSC_ARCH should not start with ".", but you have specified with '+msg)
    if not len(self.arch):
      raise RuntimeError('PETSC_ARCH cannot be empty string. Use a valid string or do not set one. Currently set with '+msg)
    self.archBase = re.sub(r'^(\w+)[-_]?.*$', r'\1', self.arch)
    return

  def makeDependency(self,hash,hashfile,hashfilepackages):
    '''Deletes the current hashfile and saves the hashfile names and its value in framework so that'''
    '''framework.Configure can create the file upon success of configure'''
    import os
    if hash:
      self.framework.hash = hash
      self.framework.hashfile = hashfile
      self.logPrint('Setting hashfile: '+hashfile)
      if hashfilepackages: self.framework.hashfilepackages = hashfilepackages
    try:
      self.logPrint('Deleting configure hash file: '+hashfile)
      os.remove(hashfile)
      self.logPrint('Deleted configure hash file: '+hashfile)
    except:
      self.logPrint('Unable to delete configure hash file: '+hashfile)


  def checkDependency(self):
    '''Checks if files in config have changed, the command line options have changed or the PATH has changed'''
    '''  By default - checks if configure needs to be run'''
    '''  If --arch-hash it manages the same information but it:'''
    '''     * computes a short hash for the configuration <hashvalue>'''
    '''     * sets self.arch and PETSC_ARCH to arch-<hashvalue>'''
    '''       This results in the downloaded packages being installed once to the arch-<hasvalue> directory'''
    '''       and a new directory with a different hash is created if the configuration changes.'''
    '''     This mode is intended mostly for testing to reduce reconfigure and recompile times (not currently used)'''
    '''  If --package-prefix-hash=directory is provided'''
    '''     * computes a short hash for the configuration <hashvalue>'''
    '''     * puts the downloaded external packages into location directory/hash'''
    '''       This results in the downloaded packages being installed once'''
    '''       and a new directory with a different hash is created if the configuration changes.'''
    '''     This mode is intended mostly for testing to reduce time of reinstalling external packages'''
    import os
    import sys
    import hashlib
    args = sorted(set(filter(lambda x: not (x.startswith('PETSC_ARCH') or x == '--force'),sys.argv[1:])))
    hash = 'args:\n' + '\n'.join('    '+a for a in args) + '\n'
    hash += 'PATH=' + os.environ.get('PATH', '') + '\n'
    chash=''
    try:
      for root, dirs, files in os.walk('config'):
        if root == 'config':
          dirs.remove('examples')
        for f in files:
          if not f.endswith('.py') or f.startswith('.') or f.startswith('#'):
            continue
          fname = os.path.join(root, f)
          with open(fname,'rb') as f:
            chash += hashlib.sha256(f.read()).hexdigest() + '  ' + fname + '\n'
    except:
      self.logPrint('Error generating file list/hash from config directory for configure hash, forcing new configuration')
      return
    hash += '\n'.join(sorted(chash.splitlines()))
    hashfilepackages = None
    # Generate short hash to use for the arch so the same arch can be reused if the configuration files don't change
    if 'arch-hash' in self.argDB:
      if self.argDB['prefix']:
        raise RuntimeError('Cannot provide --prefix and --arch-hash')
      if hasattr(self.argDB,'PETSC_ARCH'):
        raise RuntimeError('Cannot provide PETSC_ARCH and --arch-hash')
      if 'package-prefix-hash' in self.argDB:
        raise RuntimeError('Cannot provide --arch-hash and --package-prefix-hash')
      if os.getenv('PETSC_ARCH'):
        raise RuntimeError('Do not set the environmental variable PETSC_ARCH and use --arch-hash')
    if 'arch-hash' in self.argDB or 'package-prefix-hash' in self.argDB:
      import hashlib
      m = hashlib.md5()
      m.update(hash.encode('utf-8'))
      hprefix = m.hexdigest()
      if 'arch-hash' in self.argDB:
        self.argDB['PETSC_ARCH'] = 'arch-'+hprefix[0:6]
        self.arch = 'arch-'+hprefix[0:6]
      else:
        if not os.path.isdir(self.argDB['package-prefix-hash']):
          raise RuntimeError('--package-prefix-hash '+self.argDB['package-prefix-hash']+' directory does not exist\n')
        self.argDB['prefix'] = os.path.join(self.argDB['package-prefix-hash'],hprefix[0:6])
        if not os.path.isdir(self.argDB['prefix']):
          os.mkdir(self.argDB['prefix'])
          hashfilepackages = os.path.join(self.argDB['prefix'],'configure-hash')
        else:
          try:
            with open(os.path.join(self.argDB['prefix'],'configure-hash'), 'r') as f:
              a = f.read()
          except:
            self.logPrint('No previous hashfilepackages found')
            a = ''
          if a == hash:
            self.logPrint('Reusing download packages in '+self.argDB['prefix'])
            self.argDB['package-prefix-hash'] = 'reuse' # indicates prefix libraries already built, no need to rebuild

    hashfile = os.path.join(self.arch,'lib','petsc','conf','configure-hash')

    if self.argDB['force']:
      self.logPrint('Forcing a new configuration requested by use')
      self.makeDependency(hash,hashfile,hashfilepackages)
      return
    a = ''
    try:
      with open(hashfile, 'r') as f:
        a = f.read()
    except:
      self.logPrint('No previous hashfile found')
      self.makeDependency(hash,hashfile,hashfilepackages)
      return
    if a == hash:
      try:
        self.logPrint('Attempting to save lib/petsc/conf/petscvariables file')
        with open(os.path.join('lib','petsc','conf','petscvariables'), 'w') as g:
          g.write('PETSC_ARCH='+self.arch+'\n')
          g.write('PETSC_DIR='+self.petscdir.dir+'\n')
          g.write('include $(PETSC_DIR)/$(PETSC_ARCH)/lib/petsc/conf/petscvariables\n')
          self.logPrint('Saved lib/petsc/conf/petscvariables file')
      except:
        self.logPrint('Unable to save lib/petsc/conf/petscvariables file')
      self.logPrint('configure hash file: '+hashfile+' matches; no need to run configure.')
      print('Your configure options and state has not changed; no need to run configure')
      print('However you can force a configure run using the option: --force')
      sys.exit()
    self.logPrint('configure hash file: '+hashfile+' does not match\n'+a+'\n---\n'+hash+'\n need to run configure')
    self.makeDependency(hash,hashfile,hashfilepackages)

  def configure(self):
    self.executeTest(self.setNativeArchitecture)
    self.executeTest(self.configureArchitecture)
    # required by top-level configure.py
    self.framework.arch = self.arch
    self.checkDependency()
    return