#!/usr/bin/python

import ninja_syntax
import os, sys, glob
import itertools
import argparse

# utilities
def flags(*args):
    return ' '.join(itertools.chain(*args))

def includes(l):
    return ['-I"{}"'.format(x) for x in l]

def library_includes(l):
    return ['-L"{}"'.format(x) for x in l]

def libraries(l):
    return ['-l{}'.format(x) for x in l]

def dependencies(l):
    return ['-isystem "{}"'.format(x) for x in l]

def object_file(f):
    (root, ext) = os.path.splitext(f)
    return os.path.join(objdir, root + '.o')

def replace_extension(f, e):
    (root, ext) = os.path.splitext(f)
    return root + e

# command line stuff
parser = argparse.ArgumentParser()
parser.add_argument('--debug', action='store_true', help='compile with debug flags')
parser.add_argument('--cxx', metavar='<compiler>', help='compiler name to use (default: g++)', default='g++')
parser.add_argument('--ci', action='store_true', help='compile under TeamCity CI (internal use only)')
args = parser.parse_args()

# general variables
include = [ '.', os.path.join('Catch', 'include')]
depends = []
cxxflags = [ '-Wall', '-Wextra', '-pedantic', '-pedantic-errors', '-std=c++11' ]
ldflags = [ '-static' ]

if args.debug:
    cxxflags.extend(['-g', '-O0'])
else:
    cxxflags.extend(['-DNDEBUG', '-O3'])

if args.ci:
    ldflags.extend(libraries(['lua5.2', 'dl']))
    ldflags.extend(library_includes(['lib']))
    include.extend(['/usr/include/lua5.2', './lua-5.2.2/src', './include'])
else:
    ldflags.extend(libraries(['lua']))

builddir = 'bin'
objdir = 'obj'
tests = os.path.join(builddir, 'tests')

# ninja file
ninja = ninja_syntax.Writer(open('build.ninja', 'w'))

# variables
ninja.variable('ninja_required_version', '1.3')
ninja.variable('builddir', 'bin')
ninja.variable('cxx', args.cxx)
ninja.variable('cxxflags', flags(cxxflags + includes(include) + dependencies(depends)))
ninja.variable('ldflags', flags(ldflags))
ninja.newline()

# rules
ninja.rule('bootstrap', command = ' '.join(['python'] + sys.argv), generator = True)
ninja.rule('compile', command = '$cxx -MMD -MF $out.d -c $cxxflags -Werror $in -o $out',
                      deps = 'gcc', depfile = '$out.d',
                      description = 'Compiling $in to $out')
ninja.rule('link', command = '$cxx $cxxflags $in -o $out $ldflags', description = 'Creating $out')
ninja.rule('runner', command = tests)
ninja.rule('example', command = '$cxx $cxxflags $in -o $out $ldflags')
ninja.newline()

# builds
ninja.build('build.ninja', 'bootstrap', implicit = sys.argv[0])

tests_object_files = []
for f in glob.glob('test*.cpp'):
    obj = object_file(f)
    tests_object_files.append(obj)
    ninja.build(obj, 'compile', inputs = f)

examples = []
for f in glob.glob('examples/*.cpp'):
    example = os.path.join(builddir, replace_extension(f, ''))
    examples.append(example)
    ninja.build(example, 'example', inputs = f)

ninja.build(tests, 'link', inputs = tests_object_files)
ninja.build('tests', 'phony', inputs = tests)
ninja.build('examples', 'phony', inputs = examples)
ninja.build('run', 'runner', implicit = 'tests')
ninja.default('run')