# vim: set ts=8 sts=2 sw=2 tw=99 et:

#

# This file is part of AMBuild.

# 

# AMBuild is free software: you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation, either version 3 of the License, or

# (at your option) any later version.

# 

# AMBuild is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

# GNU General Public License for more details.

# 

# You should have received a copy of the GNU General Public License

# along with AMBuild. If not, see <http://www.gnu.org/licenses/>.

import os

import sys, copy

from ambuild2 import util

from ambuild2.frontend import cpp

# AMBuild 2 scripts are parsed recursively. Each script is supplied with a

# "builder" object, which maps to a Context object. Each script gets its own

# context. The context describes the parent build file generator, the local

# input and output folders, and the global compiler that was detected in the

# root script (if any).

#

# Contexts form a tree that matches the build script hierarchy. This can be

# utilized by backends for minimal reparsing and DAG updates when build

# scripts change.

class ConfigureException(Exception):

  def __init__(self, *args, **kwargs):

    super(ConfigureException, self).__init__(*args, **kwargs)

class Context(object):

  def __init__(self, generator, parent, script):

    self.generator = generator

    self.parent = parent

    self.script = script

    self.compiler = None

    if parent:

      self.compiler = parent.compiler

    # By default, all generated files for a build script are placed in a path

    # matching its layout in the source tree.

    path, name = os.path.split(script)

    if parent:

      self.currentSourcePath = os.path.join(parent.currentSourcePath, path)

      self.currentSourceFolder = os.path.join(parent.currentSourceFolder, path)

      self.buildFolder = os.path.join(parent.buildFolder, path)

    else:

      self.currentSourcePath = generator.sourcePath

      self.currentSourceFolder = ''

      self.buildFolder = ''

    self.buildScript = os.path.join(self.currentSourceFolder, name)

    self.localFolder_ = self.buildFolder

  # Root source folder.

  @property

  def sourcePath(self):

    return self.generator.sourcePath

  @property

  def options(self):

    return self.generator.options

  @property

  def buildPath(self):

    return self.generator.buildPath

  # In build systems with dependency graphs, this can return a node

  # representing buildFolder. Otherwise, it returns buildFolder.

  @property

  def localFolder(self):

    return self.generator.getLocalFolder(self)

  @property

  def target_platform(self):

    return self.generator.target_platform

  @property

  def host_platform(self):

    return self.generator.host_platform

  def SetBuildFolder(self, folder):

    if folder == '/' or folder == '.' or folder == './':

      self.buildFolder = ''

    else:

      self.buildFolder = os.path.normpath(folder)

    self.localFolder_ = self.buildFolder

  def DetectCompilers(self):

    if not self.compiler:

      self.compiler = self.generator.DetectCompilers()

    return self.compiler

  def RunScript(self, file, vars={}):

    return self.generator.evalScript(file, vars)

  def RunBuildScripts(self, files, vars={}):

    if util.IsString(files):

      self.generator.evalScript(files, vars)

    else:

      for script in files:

        self.generator.evalScript(script, vars)

  def Add(self, taskbuilder):

    taskbuilder.finish(self)

    return taskbuilder.generate(self.generator, self)

  def AddSource(self, source_path):

    return self.generator.addSource(self, source_path)

  def AddSymlink(self, source, output_path):

    return self.generator.addSymlink(self, source, output_path)

  def AddFolder(self, folder):

    return self.generator.addFolder(self, folder)

  def AddCopy(self, source, output_path):

    return self.generator.addCopy(self, source, output_path)

  def AddCommand(self, inputs, argv, outputs):

    return self.generator.addShellCommand(self, inputs, argv, outputs)

  def AddConfigureFile(self, path):

    return self.generator.addConfigureFile(self, path)

class Generator(object):

  def __init__(self, sourcePath, buildPath, options, args):

    self.sourcePath = sourcePath

    self.buildPath = os.path.normpath(buildPath)

    self.options = options

    self.args = args

    self.compiler = None

    self.contextStack_ = [None]

    self.configure_failed = False

    # This is a hack... if we ever do cross-compiling or something, we'll have

    # to change this.

    self.host_platform = util.Platform()

    self.target_platform = util.Platform()

  def parseBuildScripts(self):

    root = os.path.join(self.sourcePath, 'AMBuildScript')

    self.evalScript(root)

  def pushContext(self, cx):

    self.contextStack_.append(cx)

  def popContext(self):

    self.contextStack_.pop()

  def evalScript(self, file, vars={}):

    cx = Context(self, self.contextStack_[-1], file)

    self.pushContext(cx)

    full_path = os.path.join(self.sourcePath, cx.buildScript)

    self.addConfigureFile(cx, full_path)

    new_vars = copy.copy(vars)

    new_vars['builder'] = cx

    # Run it.

    rvalue = None

    with open(full_path) as fp:

      chars = fp.read()

      # Python 2.6 can't compile() with Windows line endings?!?!!?

      chars = chars.replace('\r\n', '\n')

      chars = chars.replace('\r', '\n')

      code = compile(chars, full_path, 'exec')

    exec(code, new_vars)

    if 'rvalue' in new_vars:

      rvalue = new_vars['rvalue']

      del new_vars['rvalue']

    self.popContext()

    return rvalue

  def generateBuildFiles(self):

    build_py = os.path.join(self.buildPath, 'build.py')

    with open(build_py, 'w') as fp:

      fp.write("""

#!{exe}

# vim set: ts=8 sts=2 sw=2 tw=99 et:

import sys

from ambuild2 import run

if not run.CompatBuild(r"{build}"):

  sys.exit(1)

""".format(exe=sys.executable, build=self.buildPath))

    with open(os.path.join(self.buildPath, 'Makefile'), 'w') as fp:

      fp.write("""

all:

	"{exe}" "{py}"

""".format(exe=sys.executable, py=build_py))

  def generate(self):

    self.preGenerate()

    self.parseBuildScripts()

    self.postGenerate()

    if self.options.make_scripts:

      self.generateBuildFiles()

    return True

  def DetectCompilers(self):

    if self.compiler:

      return self.compiler

    with util.FolderChanger('.ambuild2'):

      cc = cpp.DetectCompiler(self, os.environ, 'CC')

      cxx = cpp.DetectCompiler(self, os.environ, 'CXX')

    self.compiler = cpp.Compiler(cc, cxx)

    return self.compiler

  def getLocalFolder(self, context):

    return context.localFolder_

  def addSymlink(self, context, source, output_path):

    if util.host_platform == 'windows':

      # Windows pre-Vista does not support symlinks. Windows Vista+ supports

      # symlinks via mklink, but it's Administrator-only by default.

      return self.addCopy(context, source, output_path)

    raise Exception('Must be implemented!')

  def addFolder(self, context, folder):

    raise Exception('Must be implemented!')

  def addCopy(self, context, source, output_path):

    raise Exception('Must be implemented!')

  def addShellCommand(self, context, inputs, argv, outputs):

    raise Exception('Must be implemented!')

  def addConfigureFile(self, context, path):

    raise Exception('Must be implemented!')