# Copyright 2014 The Emscripten Authors.  All rights reserved.
# Emscripten is available under two separate licenses, the MIT license and the
# University of Illinois/NCSA Open Source License.  Both these licenses can be
# found in the LICENSE file.

import logging
import hashlib
import os
import shutil
import sys
import glob
from tools import config
from tools import shared
from tools import system_libs
from tools import utils
from tools.settings import settings

ports = []

ports_by_name = {}

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

logger = logging.getLogger('ports')


def read_ports():
  expected_attrs = ['get', 'clear', 'process_args', 'show', 'needed']
  for filename in os.listdir(ports_dir):
    if not filename.endswith('.py') or filename == '__init__.py':
      continue
    filename = os.path.splitext(filename)[0]
    port = __import__(filename, globals(), level=1)
    ports.append(port)
    port.name = filename
    ports_by_name[port.name] = port
    for a in expected_attrs:
      assert hasattr(port, a), 'port %s is missing %s' % (port, a)
    if not hasattr(port, 'process_dependencies'):
      port.process_dependencies = lambda x: 0
    if not hasattr(port, 'linker_setup'):
      port.linker_setup = lambda x, y: 0
    if not hasattr(port, 'deps'):
      port.deps = []

  for dep in port.deps:
    if dep not in ports_by_name:
      utils.exit_with_error('unknown dependency in port: %s' % dep)


def get_all_files_under(dirname):
  for path, subdirs, files in os.walk(dirname):
    for name in files:
      yield os.path.join(path, name)


def dir_is_newer(dir_a, dir_b):
  assert os.path.exists(dir_a)
  assert os.path.exists(dir_b)
  newest_a = max([os.path.getmtime(x) for x in get_all_files_under(dir_a)])
  newest_b = max([os.path.getmtime(x) for x in get_all_files_under(dir_b)])
  return newest_a < newest_b


class Ports:
  """emscripten-ports library management (https://github.com/emscripten-ports).
  """

  @staticmethod
  def get_include_dir(*parts):
    dirname = shared.Cache.get_include_dir(*parts)
    shared.safe_ensure_dirs(dirname)
    return dirname

  @staticmethod
  def install_header_dir(src_dir, target=None):
    if not target:
      target = os.path.basename(src_dir)
    dest = os.path.join(Ports.get_include_dir(), target)
    shared.try_delete(dest)
    logger.debug(f'installing headers: {dest}')
    shutil.copytree(src_dir, dest)

  @staticmethod
  def install_headers(src_dir, pattern='*.h', target=None):
    logger.debug('install_headers')
    dest = Ports.get_include_dir()
    if target:
      dest = os.path.join(dest, target)
      shared.safe_ensure_dirs(dest)
    matches = glob.glob(os.path.join(src_dir, pattern))
    assert matches, f'no headers found to install in {src_dir}'
    for f in matches:
      logger.debug('installing: ' + os.path.join(dest, os.path.basename(f)))
      shutil.copyfile(f, os.path.join(dest, os.path.basename(f)))

  @staticmethod
  def build_port(src_path, output_path, includes=[], flags=[], exclude_files=[], exclude_dirs=[]):
    srcs = []
    for root, dirs, files in os.walk(src_path, topdown=False):
      if any((excluded in root) for excluded in exclude_dirs):
        continue
      for f in files:
        ext = shared.suffix(f)
        if ext in ('.c', '.cpp') and not any((excluded in f) for excluded in exclude_files):
          srcs.append(os.path.join(root, f))
    include_commands = ['-I' + src_path]
    for include in includes:
      include_commands.append('-I' + include)

    commands = []
    objects = []
    for src in srcs:
      obj = src + '.o'
      commands.append([shared.EMCC, '-c', src, '-O2', '-o', obj, '-w'] + include_commands + flags)
      objects.append(obj)

    Ports.run_commands(commands)
    system_libs.create_lib(output_path, objects)
    return output_path

  @staticmethod
  def run_commands(commands):
    # Runs a sequence of compiler commands, adding importand cflags as defined by get_cflags() so
    # that the ports are built in the correct configuration.
    def add_args(cmd):
      # this must only be called on a standard build command
      assert cmd[0] in (shared.EMCC, shared.EMXX)
      # add standard cflags, but also allow the cmd to override them
      return cmd[:1] + system_libs.get_base_cflags() + cmd[1:]
    system_libs.run_build_commands([add_args(c) for c in commands])

  @staticmethod
  def create_lib(libname, inputs): # make easily available for port objects
    system_libs.create_lib(libname, inputs)

  @staticmethod
  def get_dir():
    dirname = config.PORTS
    shared.safe_ensure_dirs(dirname)
    return dirname

  @staticmethod
  def erase():
    dirname = Ports.get_dir()
    shared.try_delete(dirname)
    if os.path.exists(dirname):
      logger.warning('could not delete ports dir %s - try to delete it manually' % dirname)

  @staticmethod
  def get_build_dir():
    return shared.Cache.get_path('ports-builds')

  name_cache = set()

  @staticmethod
  def fetch_project(name, url, subdir, sha512hash=None):
    # To compute the sha512 hash, run `curl URL | sha512sum`.
    fullname = os.path.join(Ports.get_dir(), name)

    # EMCC_LOCAL_PORTS: A hacky way to use a local directory for a port. This
    #                   is not tested but can be useful for debugging
    #                   changes to a port.
    #
    # if EMCC_LOCAL_PORTS is set, we use a local directory as our ports. This is useful
    # for testing. This env var should be in format
    #     name=dir,name=dir
    # e.g.
    #     sdl2=/home/username/dev/ports/SDL2
    # so you could run
    #     EMCC_LOCAL_PORTS="sdl2=/home/alon/Dev/ports/SDL2" ./tests/runner.py browser.test_sdl2_mouse
    # this will simply copy that directory into the ports directory for sdl2, and use that. It also
    # clears the build, so that it is rebuilt from that source.
    local_ports = os.environ.get('EMCC_LOCAL_PORTS')
    if local_ports:
      logger.warning('using local ports: %s' % local_ports)
      local_ports = [pair.split('=', 1) for pair in local_ports.split(',')]
      with shared.Cache.lock():
        for local in local_ports:
          if name == local[0]:
            path = local[1]
            if name not in ports_by_name:
              utils.exit_with_error('%s is not a known port' % name)
            port = ports_by_name[name]
            if not hasattr(port, 'SUBDIR'):
              logger.error(f'port {name} lacks .SUBDIR attribute, which we need in order to override it locally, please update it')
              sys.exit(1)
            subdir = port.SUBDIR
            target = os.path.join(fullname, subdir)
            if os.path.exists(target) and not dir_is_newer(path, target):
              logger.warning(f'not grabbing local port: {name} from {path} to {fullname} (subdir: {subdir}) as the destination {target} is newer (run emcc --clear-ports if that is incorrect)')
            else:
              logger.warning(f'grabbing local port: {name} from {path} to {fullname} (subdir: {subdir})')
              shared.try_delete(fullname)
              shutil.copytree(path, target)
              Ports.clear_project_build(name)
            return

    url_filename = url.rsplit('/')[-1]
    ext = url_filename.split('.', 1)[1]
    fullpath = fullname + '.' + ext

    if name not in Ports.name_cache: # only mention each port once in log
      logger.debug(f'including port: {name}')
      logger.debug(f'    (at {fullname})')
      Ports.name_cache.add(name)

    def retrieve():
      # retrieve from remote server
      logger.info(f'retrieving port: {name} from {url}')
      try:
        import requests
        response = requests.get(url)
        data = response.content
      except ImportError:
        from urllib.request import urlopen
        f = urlopen(url)
        data = f.read()

      if sha512hash:
        actual_hash = hashlib.sha512(data).hexdigest()
        if actual_hash != sha512hash:
          utils.exit_with_error(f'Unexpected hash: {actual_hash}\n'
                                'If you are updating the port, please update the hash.')
      utils.write_binary(fullpath, data)

    marker = os.path.join(fullname, '.emscripten_url')

    def unpack():
      logger.info(f'unpacking port: {name}')
      shared.safe_ensure_dirs(fullname)
      shutil.unpack_archive(filename=fullpath, extract_dir=fullname)
      utils.write_file(marker, url + '\n')

    def up_to_date():
      if os.path.exists(marker):
        if utils.read_file(marker).strip() == url:
          return True
      return False

    # before acquiring the lock we have an early out if the port already exists
    if up_to_date():
      return

    # main logic. do this under a cache lock, since we don't want multiple jobs to
    # retrieve the same port at once
    with shared.Cache.lock():
      if os.path.exists(fullpath):
        # Another early out in case another process build the library while we were
        # waiting for the lock
        if up_to_date():
          return
        # file exists but tag is bad
        logger.warning('local copy of port is not correct, retrieving from remote server')
        shared.try_delete(fullname)
        shared.try_delete(fullpath)

      retrieve()
      unpack()

      # we unpacked a new version, clear the build in the cache
      Ports.clear_project_build(name)

  @staticmethod
  def clear_project_build(name):
    port = ports_by_name[name]
    port.clear(Ports, settings, shared)
    shared.try_delete(os.path.join(Ports.get_build_dir(), name))


def dependency_order(port_list):
  # Perform topological sort of ports according to the dependency DAG
  port_map = {p.name: p for p in port_list}

  # Perform depth first search of dependecy graph adding nodes to
  # the stack only after all children have been explored.
  stack = []
  unsorted = set(port_list)

  def dfs(node):
    for dep in node.deps:
      child = port_map[dep]
      if child in unsorted:
        unsorted.remove(child)
        dfs(child)
    stack.append(node)

  while unsorted:
    dfs(unsorted.pop())

  return stack


def resolve_dependencies(port_set, settings):
  def add_deps(node):
    node.process_dependencies(settings)
    for d in node.deps:
      dep = ports_by_name[d]
      if dep not in port_set:
        port_set.add(dep)
        add_deps(dep)

  for port in port_set.copy():
    add_deps(port)


def get_needed_ports(settings):
  # Start with directly needed ports, and transitively add dependencies
  needed = set(p for p in ports if p.needed(settings))
  resolve_dependencies(needed, settings)
  return needed


def build_port(port_name, settings):
  port = ports_by_name[port_name]
  port_set = set((port,))
  resolve_dependencies(port_set, settings)
  for port in dependency_order(port_set):
    port.get(Ports, settings, shared)


def clear_port(port_name, settings):
  port = ports_by_name[port_name]
  port.clear(Ports, settings, shared)


def clear():
  Ports.erase()


def get_libs(settings):
  """Called add link time to calculate the list of port libraries.
  Can have the side effect of building and installing the needed ports.
  """
  ret = []
  needed = get_needed_ports(settings)

  for port in dependency_order(needed):
    if port.needed(settings):
      port.linker_setup(Ports, settings)
      # ports return their output files, which will be linked, or a txt file
      ret += [f for f in port.get(Ports, settings, shared) if not f.endswith('.txt')]

  ret.reverse()
  return ret


def add_cflags(args, settings): # noqa: U100
  """Called during compile phase add any compiler flags (e.g -Ifoo) needed
  by the selected ports.  Can also add/change settings.

  Can have the side effect of building and installing the needed ports.
  """

  # Legacy SDL1 port is not actually a port at all but builtin
  if settings.USE_SDL == 1:
    args += ['-Xclang', '-iwithsysroot/include/SDL']

  needed = get_needed_ports(settings)

  # Now get (i.e. build) the ports in dependency order.  This is important because the
  # headers from one ports might be needed before we can build the next.
  for port in dependency_order(needed):
    port.get(Ports, settings, shared)
    args += port.process_args(Ports)


def show_ports():
  print('Available ports:')
  for port in ports:
    print('   ', port.show())


read_ports()
