#!/usr/bin/env python

import os, sys, subprocess, argparse, shutil, glob, re, multiprocessing
import logging as log

SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))

class Fail(Exception):
    def __init__(self, text=None):
        self.t = text
    def __str__(self):
        return "ERROR" if self.t is None else self.t

def execute(cmd, shell=False):
    try:
        log.info("Executing: %s" % cmd)
        env = os.environ.copy()
        env['VERBOSE'] = '1'
        retcode = subprocess.call(cmd, shell=shell, env=env)
        if retcode < 0:
            raise Fail("Child was terminated by signal: %s" % -retcode)
        elif retcode > 0:
            raise Fail("Child returned: %s" % retcode)
    except OSError as e:
        raise Fail("Execution failed: %d / %s" % (e.errno, e.strerror))

def rm_one(d):
    d = os.path.abspath(d)
    if os.path.exists(d):
        if os.path.isdir(d):
            log.info("Removing dir: %s", d)
            shutil.rmtree(d)
        elif os.path.isfile(d):
            log.info("Removing file: %s", d)
            os.remove(d)

def check_dir(d, create=False, clean=False):
    d = os.path.abspath(d)
    log.info("Check dir %s (create: %s, clean: %s)", d, create, clean)
    if os.path.exists(d):
        if not os.path.isdir(d):
            raise Fail("Not a directory: %s" % d)
        if clean:
            for x in glob.glob(os.path.join(d, "*")):
                rm_one(x)
    else:
        if create:
            os.makedirs(d)
    return d

def check_file(d):
    d = os.path.abspath(d)
    if os.path.exists(d):
        if os.path.isfile(d):
            return True
        else:
            return False
    return False

def find_file(name, path):
    for root, dirs, files in os.walk(path):
        if name in files:
            return os.path.join(root, name)

class Builder:
    def __init__(self, options):
        self.options = options
        self.build_dir = check_dir(options.build_dir, create=True)
        self.opencv_dir = check_dir(options.opencv_dir)
        self.emscripten_dir = check_dir(options.emscripten_dir)

    def get_toolchain_file(self):
        return os.path.join(self.emscripten_dir, "cmake", "Modules", "Platform", "Emscripten.cmake")

    def clean_build_dir(self):
        for d in ["CMakeCache.txt", "CMakeFiles/", "bin/", "libs/", "lib/", "modules"]:
            rm_one(d)

    def get_cmake_cmd(self):
        cmd = [
            "cmake",
            "-DPYTHON_DEFAULT_EXECUTABLE=%s" % sys.executable,
               "-DENABLE_PIC=FALSE", # To workaround emscripten upstream backend issue https://github.com/emscripten-core/emscripten/issues/8761
               "-DCMAKE_BUILD_TYPE=Release",
               "-DCMAKE_TOOLCHAIN_FILE='%s'" % self.get_toolchain_file(),
               "-DCPU_BASELINE=''",
               "-DCPU_DISPATCH=''",
               "-DCV_TRACE=OFF",
               "-DBUILD_SHARED_LIBS=OFF",
               "-DWITH_1394=OFF",
               "-DWITH_VTK=OFF",
               "-DWITH_EIGEN=OFF",
               "-DWITH_FFMPEG=OFF",
               "-DWITH_GSTREAMER=OFF",
               "-DWITH_GTK=OFF",
               "-DWITH_GTK_2_X=OFF",
               "-DWITH_IPP=OFF",
               "-DWITH_JASPER=OFF",
               "-DWITH_JPEG=OFF",
               "-DWITH_WEBP=OFF",
               "-DWITH_OPENEXR=OFF",
               "-DWITH_OPENGL=OFF",
               "-DWITH_OPENVX=OFF",
               "-DWITH_OPENNI=OFF",
               "-DWITH_OPENNI2=OFF",
               "-DWITH_PNG=OFF",
               "-DWITH_TBB=OFF",
               "-DWITH_TIFF=OFF",
               "-DWITH_V4L=OFF",
               "-DWITH_OPENCL=OFF",
               "-DWITH_OPENCL_SVM=OFF",
               "-DWITH_OPENCLAMDFFT=OFF",
               "-DWITH_OPENCLAMDBLAS=OFF",
               "-DWITH_GPHOTO2=OFF",
               "-DWITH_LAPACK=OFF",
               "-DWITH_ITT=OFF",
               "-DWITH_QUIRC=ON",
               "-DBUILD_ZLIB=ON",
               "-DBUILD_opencv_apps=OFF",
               "-DBUILD_opencv_calib3d=ON",
               "-DBUILD_opencv_dnn=ON",
               "-DBUILD_opencv_features2d=ON",
               "-DBUILD_opencv_flann=OFF",
               "-DBUILD_opencv_ml=OFF",
               "-DBUILD_opencv_photo=OFF",
               "-DBUILD_opencv_imgcodecs=OFF",
               "-DBUILD_opencv_shape=OFF",
               "-DBUILD_opencv_videoio=OFF",
               "-DBUILD_opencv_videostab=OFF",
               "-DBUILD_opencv_highgui=OFF",
               "-DBUILD_opencv_superres=OFF",
               "-DBUILD_opencv_stitching=OFF",
               "-DBUILD_opencv_java=OFF",
               "-DBUILD_opencv_js=ON",
               "-DBUILD_opencv_python2=OFF",
               "-DBUILD_opencv_python3=OFF",
               "-DBUILD_EXAMPLES=OFF",
               "-DBUILD_PACKAGE=OFF",
               "-DBUILD_TESTS=OFF",
               "-DBUILD_PERF_TESTS=OFF"]
        if self.options.cmake_option:
            cmd += self.options.cmake_option
        if self.options.build_doc:
            cmd.append("-DBUILD_DOCS=ON")
        else:
            cmd.append("-DBUILD_DOCS=OFF")

        if self.options.threads:
            cmd.append("-DWITH_PTHREADS_PF=ON")
        else:
            cmd.append("-DWITH_PTHREADS_PF=OFF")

        if self.options.simd:
            cmd.append("-DCV_ENABLE_INTRINSICS=ON")
        else:
            cmd.append("-DCV_ENABLE_INTRINSICS=OFF")

        if self.options.build_wasm_intrin_test:
            cmd.append("-DBUILD_WASM_INTRIN_TESTS=ON")
        else:
            cmd.append("-DBUILD_WASM_INTRIN_TESTS=OFF")

        flags = self.get_build_flags()
        if flags:
            cmd += ["-DCMAKE_C_FLAGS='%s'" % flags,
                    "-DCMAKE_CXX_FLAGS='%s'" % flags]
        return cmd

    def get_build_flags(self):
        flags = ""
        if self.options.build_wasm:
            flags += "-s WASM=1 "
        elif self.options.disable_wasm:
            flags += "-s WASM=0 "
        if self.options.threads:
            flags += "-s USE_PTHREADS=1 -s PTHREAD_POOL_SIZE=4 "
        else:
            flags += "-s USE_PTHREADS=0 "
        if self.options.enable_exception:
            flags += "-s DISABLE_EXCEPTION_CATCHING=0 "
        if self.options.simd:
            flags += "-msimd128 "
        if self.options.build_flags:
            flags += self.options.build_flags
        return flags

    def config(self):
        cmd = self.get_cmake_cmd()
        cmd.append(self.opencv_dir)
        execute(cmd)

    def build_opencvjs(self):
        execute(["make", "-j", str(multiprocessing.cpu_count()), "opencv.js"])

    def build_test(self):
        execute(["make", "-j", str(multiprocessing.cpu_count()), "opencv_js_test"])

    def build_perf(self):
        execute(["make", "-j", str(multiprocessing.cpu_count()), "opencv_js_perf"])

    def build_doc(self):
        execute(["make", "-j", str(multiprocessing.cpu_count()), "doxygen"])

    def build_loader(self):
        execute(["make", "-j", str(multiprocessing.cpu_count()), "opencv_js_loader"])


#===================================================================================================

if __name__ == "__main__":
    log.basicConfig(format='%(message)s', level=log.DEBUG)

    opencv_dir = os.path.abspath(os.path.join(SCRIPT_DIR, '../..'))
    emscripten_dir = None
    if "EMSCRIPTEN" in os.environ:
        emscripten_dir = os.environ["EMSCRIPTEN"]
    else:
        log.warning("EMSCRIPTEN environment variable is not available. Please properly activate Emscripten SDK and consider using 'emcmake' launcher")

    parser = argparse.ArgumentParser(description='Build OpenCV.js by Emscripten')
    parser.add_argument("build_dir", help="Building directory (and output)")
    parser.add_argument('--opencv_dir', default=opencv_dir, help='Opencv source directory (default is "../.." relative to script location)')
    parser.add_argument('--emscripten_dir', default=emscripten_dir, help="Path to Emscripten to use for build (deprecated in favor of 'emcmake' launcher)")
    parser.add_argument('--build_wasm', action="store_true", help="Build OpenCV.js in WebAssembly format")
    parser.add_argument('--disable_wasm', action="store_true", help="Build OpenCV.js in Asm.js format")
    parser.add_argument('--threads', action="store_true", help="Build OpenCV.js with threads optimization")
    parser.add_argument('--simd', action="store_true", help="Build OpenCV.js with SIMD optimization")
    parser.add_argument('--build_test', action="store_true", help="Build tests")
    parser.add_argument('--build_perf', action="store_true", help="Build performance tests")
    parser.add_argument('--build_doc', action="store_true", help="Build tutorials")
    parser.add_argument('--build_loader', action="store_true", help="Build OpenCV.js loader")
    parser.add_argument('--clean_build_dir', action="store_true", help="Clean build dir")
    parser.add_argument('--skip_config', action="store_true", help="Skip cmake config")
    parser.add_argument('--config_only', action="store_true", help="Only do cmake config")
    parser.add_argument('--enable_exception', action="store_true", help="Enable exception handling")
    # Use flag --cmake option="-D...=ON" only for one argument, if you would add more changes write new cmake_option flags
    parser.add_argument('--cmake_option', action='append', help="Append CMake options")
    # Use flag --build_flags="-s USE_PTHREADS=0 -Os" for one and more arguments as in the example
    parser.add_argument('--build_flags', help="Append Emscripten build options")
    parser.add_argument('--build_wasm_intrin_test', default=False, action="store_true", help="Build WASM intrin tests")
    # Write a path to modify file like argument of this flag
    parser.add_argument('--config', default=os.path.join(os.path.dirname(os.path.abspath(__file__)), 'opencv_js.config.py'),
                        help="Specify configuration file with own list of exported into JS functions")

    args = parser.parse_args()

    log.debug("Args: %s", args)

    os.environ["OPENCV_JS_WHITELIST"] = os.path.abspath(args.config)

    if 'EMMAKEN_JUST_CONFIGURE' in os.environ:
        del os.environ['EMMAKEN_JUST_CONFIGURE']  # avoid linker errors with NODERAWFS message then using 'emcmake' launcher

    if args.emscripten_dir is None:
        log.error("Cannot get Emscripten path, please use 'emcmake' launcher or specify it either by EMSCRIPTEN environment variable or --emscripten_dir option.")
        sys.exit(-1)

    builder = Builder(args)

    os.chdir(builder.build_dir)

    if args.clean_build_dir:
        log.info("=====")
        log.info("===== Clean build dir %s", builder.build_dir)
        log.info("=====")
        builder.clean_build_dir()

    if not args.skip_config:
        target = "default target"
        if args.build_wasm:
            target = "wasm"
        elif args.disable_wasm:
            target = "asm.js"
        log.info("=====")
        log.info("===== Config OpenCV.js build for %s" % target)
        log.info("=====")
        builder.config()

    if args.config_only:
        sys.exit(0)

    log.info("=====")
    log.info("===== Building OpenCV.js")
    log.info("=====")
    builder.build_opencvjs()

    if args.build_test:
        log.info("=====")
        log.info("===== Building OpenCV.js tests")
        log.info("=====")
        builder.build_test()

    if args.build_perf:
        log.info("=====")
        log.info("===== Building OpenCV.js performance tests")
        log.info("=====")
        builder.build_perf()

    if args.build_doc:
        log.info("=====")
        log.info("===== Building OpenCV.js tutorials")
        log.info("=====")
        builder.build_doc()

    if args.build_loader:
        log.info("=====")
        log.info("===== Building OpenCV.js loader")
        log.info("=====")
        builder.build_loader()

    log.info("=====")
    log.info("===== Build finished")
    log.info("=====")

    opencvjs_path = os.path.join(builder.build_dir, "bin", "opencv.js")
    if check_file(opencvjs_path):
        log.info("OpenCV.js location: %s", opencvjs_path)

    if args.build_test:
        opencvjs_test_path = os.path.join(builder.build_dir, "bin", "tests.html")
        if check_file(opencvjs_test_path):
            log.info("OpenCV.js tests location: %s", opencvjs_test_path)

    if args.build_perf:
        opencvjs_perf_path = os.path.join(builder.build_dir, "bin", "perf")
        opencvjs_perf_base_path = os.path.join(builder.build_dir, "bin", "perf", "base.js")
        if check_file(opencvjs_perf_base_path):
            log.info("OpenCV.js performance tests location: %s", opencvjs_perf_path)

    if args.build_doc:
        opencvjs_tutorial_path = find_file("tutorial_js_root.html", os.path.join(builder.build_dir, "doc", "doxygen", "html"))
        if check_file(opencvjs_tutorial_path):
            log.info("OpenCV.js tutorials location: %s", opencvjs_tutorial_path)

    if args.build_loader:
        opencvjs_loader_path = os.path.join(builder.build_dir, "bin", "loader.js")
        if check_file(opencvjs_loader_path):
            log.info("OpenCV.js loader location: %s", opencvjs_loader_path)
