import re

import subprocess

# import feature, taskgen_method, before_method, task_gen

from waflib import TaskGen, Node, Task, Utils, Build, Options, Logs, Task

debug = Logs.debug

error = Logs.error

import shellcmd

#shellcmd.subprocess = pproc # the WAF version of the subprocess module is supposedly less buggy

shellcmd.debug = debug

arg_rx = re.compile(r"(?P<dollar>\$\$)|(?P<subst>\$\{(?P<var>\w+)(?P<code>.*?)\})", re.M)

class command_task(Task.Task):

	color = "BLUE"

	def __init__(self, env, generator):

		Task.Task.__init__(self, env=env, normal=1, generator=generator)

	def __str__(self):

		"string to display to the user"

		env = self.env

		src_str = ' '.join([a.nice_path(env) for a in self.inputs])

		tgt_str = ' '.join([a.nice_path(env) for a in self.outputs])

		if self.outputs:

			sep = ' -> '

		else:

			sep = ''

		pipeline = shellcmd.Pipeline()

		pipeline.parse(self.generator.command)

		cmd = pipeline.get_abbreviated_command()

		return 'command (%s): %s%s%s\n' % (cmd, src_str, sep, tgt_str)

	def _subst_arg(self, arg, direction, namespace):

		"""

		@param arg: the command argument (or stdin/stdout/stderr) to substitute

		@param direction: direction of the argument: 'in', 'out', or None

		"""

		def repl(match):

			if match.group('dollar'):

				return "$"

			elif match.group('subst'):

				var = match.group('var')

				code = match.group('code')

				result = eval(var+code, namespace)

				if isinstance(result, Node.Node):

					if var == 'TGT':

						return result.get_bld().abspath()

					elif var == 'SRC':

						return result.srcpath()

					else:

						raise ValueError("Bad subst variable %r" % var)

				elif result is self.inputs:

					if len(self.inputs) == 1:

						return result[0].srcpath()

					else:

						raise ValueError("${SRC} requested but have multiple sources; which one?")

				elif result is self.outputs:

					if len(self.outputs) == 1:

						return result[0].get_bld().abspath()

					else:

						raise ValueError("${TGT} requested but have multiple targets; which one?")

				elif isinstance(result, list):

					assert len(result) == 1

					return result[0]

				else:

					return result

			return None

		return arg_rx.sub(repl, arg)

	def run(self):

		pipeline = shellcmd.Pipeline()

		pipeline.parse(self.generator.command)

		namespace = self.env.get_merged_dict()

		if self.generator.variables is not None:

			namespace.update(self.generator.variables)

		namespace.update(env=self.env, SRC=self.inputs, TGT=self.outputs)

		for cmd in pipeline.pipeline:

			if isinstance(cmd, shellcmd.Command):

				if isinstance(cmd.stdin, basestring):

					cmd.stdin = self._subst_arg(cmd.stdin, 'in', namespace)

				if isinstance(cmd.stdout, basestring):

					cmd.stdout = self._subst_arg(cmd.stdout, 'out', namespace)

				if isinstance(cmd.stderr, basestring):

					cmd.stderr = self._subst_arg(cmd.stderr, 'out', namespace)

				for argI in xrange(len(cmd.argv)):

					cmd.argv[argI] = self._subst_arg(cmd.argv[argI], None, namespace)

				if cmd.env_vars is not None:

					env_vars = dict()

					for name, value in cmd.env_vars.iteritems():

						env_vars[name] = self._subst_arg(value, None, namespace)

					cmd.env_vars = env_vars

			elif isinstance(cmd, shellcmd.Chdir):

				cmd.dir = self._subst_arg(cmd.dir, None, namespace)

		return pipeline.run(verbose=(Options.options.verbose > 0))

@TaskGen.taskgen_method

@TaskGen.feature('command')

def init_command(self):

	Utils.def_attrs(self,

					# other variables that can be used in the command: ${VARIABLE}

					variables = None,

					rule='')

@TaskGen.feature('command')

@TaskGen.after_method('process_rule')

def apply_command(self):

	#self.meths.remove('apply_core')

	# create the task

	task = self.create_task('command')

	setattr(task, "dep_vars", getattr(self, "dep_vars", None))

	# process the sources

	inputs = []

	for node in self.source:

		inputs.append(node)

	task.set_inputs(inputs)

	task.set_outputs([self.path.find_or_declare(tgt) for tgt in self.to_list(self.target)])

	self.source = ''

	#Task.file_deps = Task.extract_deps

# class command_taskgen(task_gen):

# 	def __init__(self, *k, **kw):

# 		task_gen.__init__(self, *k, **kw)

# 		self.features.append('command')