#! /usr/bin/env python3
# encoding: UTF-8
# Petar Forai
# Thomas Nagy 2008-2010 (ita)

import re
from waflib import Task, Logs
from waflib.TaskGen import extension, feature, after_method
from waflib.Configure import conf
from waflib.Tools import c_preproc

"""
tasks have to be added dynamically:
- swig interface files may be created at runtime
- the module name may be unknown in advance
"""

SWIG_EXTS = ['.swig', '.i']

re_module = re.compile(r'%module(?:\s*\(.*\))?\s+(.+)', re.M)

re_1 = re.compile(r'^%module.*?\s+([\w]+)\s*?$', re.M)
re_2 = re.compile(r'[#%](?:include|import(?:\(module=".*"\))+|python(?:begin|code)) [<"](.*)[">]', re.M)

class swig(Task.Task):
	color   = 'BLUE'
	run_str = '${SWIG} ${SWIGFLAGS} ${SWIGPATH_ST:INCPATHS} ${SWIGDEF_ST:DEFINES} ${SRC}'
	ext_out = ['.h'] # might produce .h files although it is not mandatory
	vars = ['SWIG_VERSION', 'SWIGDEPS']

	def runnable_status(self):
		for t in self.run_after:
			if not t.hasrun:
				return Task.ASK_LATER

		if not getattr(self, 'init_outputs', None):
			self.init_outputs = True
			if not getattr(self, 'module', None):
				# search the module name
				txt = self.inputs[0].read()
				m = re_module.search(txt)
				if not m:
					raise ValueError("could not find the swig module name")
				self.module = m.group(1)

			swig_c(self)

			# add the language-specific output files as nodes
			# call funs in the dict swig_langs
			for x in self.env['SWIGFLAGS']:
				# obtain the language
				x = x[1:]
				try:
					fun = swig_langs[x]
				except KeyError:
					pass
				else:
					fun(self)

		return super(swig, self).runnable_status()

	def scan(self):
		"scan for swig dependencies, climb the .i files"
		lst_src = []

		seen = []
		missing = []
		to_see = [self.inputs[0]]

		while to_see:
			node = to_see.pop(0)
			if node in seen:
				continue
			seen.append(node)
			lst_src.append(node)

			# read the file
			code = node.read()
			code = c_preproc.re_nl.sub('', code)
			code = c_preproc.re_cpp.sub(c_preproc.repl, code)

			# find .i files and project headers
			names = re_2.findall(code)
			for n in names:
				for d in self.generator.includes_nodes + [node.parent]:
					u = d.find_resource(n)
					if u:
						to_see.append(u)
						break
				else:
					missing.append(n)
		return (lst_src, missing)

# provide additional language processing
swig_langs = {}
def swigf(fun):
	swig_langs[fun.__name__.replace('swig_', '')] = fun
	return fun
swig.swigf = swigf

def swig_c(self):
	ext = '.swigwrap_%d.c' % self.generator.idx
	flags = self.env['SWIGFLAGS']
	if '-c++' in flags:
		ext += 'xx'
	out_node = self.inputs[0].parent.find_or_declare(self.module + ext)

	if '-c++' in flags:
		c_tsk = self.generator.cxx_hook(out_node)
	else:
		c_tsk = self.generator.c_hook(out_node)

	c_tsk.set_run_after(self)

	# transfer weights from swig task to c task
	if getattr(self, 'weight', None):
		c_tsk.weight = self.weight
	if getattr(self, 'tree_weight', None):
		c_tsk.tree_weight = self.tree_weight

	try:
		self.more_tasks.append(c_tsk)
	except AttributeError:
		self.more_tasks = [c_tsk]

	try:
		ltask = self.generator.link_task
	except AttributeError:
		pass
	else:
		ltask.set_run_after(c_tsk)
		# setting input nodes does not declare the build order
		# because the build already started, but it sets
		# the dependency to enable rebuilds
		ltask.inputs.append(c_tsk.outputs[0])

	self.outputs.append(out_node)

	if not '-o' in self.env['SWIGFLAGS']:
		self.env.append_value('SWIGFLAGS', ['-o', self.outputs[0].abspath()])

@swigf
def swig_python(tsk):
	node = tsk.inputs[0].parent
	if tsk.outdir:
		node = tsk.outdir
	tsk.set_outputs(node.find_or_declare(tsk.module+'.py'))

@swigf
def swig_ocaml(tsk):
	node = tsk.inputs[0].parent
	if tsk.outdir:
		node = tsk.outdir
	tsk.set_outputs(node.find_or_declare(tsk.module+'.ml'))
	tsk.set_outputs(node.find_or_declare(tsk.module+'.mli'))

@extension(*SWIG_EXTS)
def i_file(self, node):
	# the task instance
	tsk = self.create_task('swig')
	tsk.set_inputs(node)
	tsk.module = getattr(self, 'swig_module', None)

	flags = self.to_list(getattr(self, 'swig_flags', []))
	tsk.env.append_value('SWIGFLAGS', flags)

	tsk.outdir = None
	if '-outdir' in flags:
		outdir = flags[flags.index('-outdir')+1]
		outdir = tsk.generator.bld.bldnode.make_node(outdir)
		outdir.mkdir()
		tsk.outdir = outdir

@feature('c', 'cxx', 'd', 'fc', 'asm')
@after_method('apply_link', 'process_source')
def enforce_swig_before_link(self):
	try:
		link_task = self.link_task
	except AttributeError:
		pass
	else:
		for x in self.tasks:
			if x.__class__.__name__ == 'swig':
				link_task.run_after.add(x)

@conf
def check_swig_version(conf, minver=None):
	"""
	Check if the swig tool is found matching a given minimum version.
	minver should be a tuple, eg. to check for swig >= 1.3.28 pass (1,3,28) as minver.

	If successful, SWIG_VERSION is defined as 'MAJOR.MINOR'
	(eg. '1.3') of the actual swig version found.

	:param minver: minimum version
	:type minver: tuple of int
	:return: swig version
	:rtype: tuple of int
	"""
	assert minver is None or isinstance(minver, tuple)
	swigbin = conf.env['SWIG']
	if not swigbin:
		conf.fatal('could not find the swig executable')

	# Get swig version string
	cmd = swigbin + ['-version']
	Logs.debug('swig: Running swig command %r', cmd)
	reg_swig = re.compile(r'SWIG Version\s(.*)', re.M)
	swig_out = conf.cmd_and_log(cmd)
	swigver_tuple = tuple([int(s) for s in reg_swig.findall(swig_out)[0].split('.')])

	# Compare swig version with the minimum required
	result = (minver is None) or (swigver_tuple >= minver)

	if result:
		# Define useful environment variables
		swigver = '.'.join([str(x) for x in swigver_tuple[:2]])
		conf.env['SWIG_VERSION'] = swigver

	# Feedback
	swigver_full = '.'.join(map(str, swigver_tuple[:3]))
	if minver is None:
		conf.msg('Checking for swig version', swigver_full)
	else:
		minver_str = '.'.join(map(str, minver))
		conf.msg('Checking for swig version >= %s' % (minver_str,), swigver_full, color=result and 'GREEN' or 'YELLOW')

	if not result:
		conf.fatal('The swig version is too old, expecting %r' % (minver,))

	return swigver_tuple

def configure(conf):
	conf.find_program('swig', var='SWIG')
	conf.env.SWIGPATH_ST = '-I%s'
	conf.env.SWIGDEF_ST = '-D%s'