# Copyright 2016 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.


import contextlib
import os
import sys

from pylib import constants

DIR_SOURCE_ROOT = os.environ.get(
    'CHECKOUT_SOURCE_ROOT',
    os.path.abspath(
        os.path.join(
            os.path.dirname(__file__),
            os.pardir,
            os.pardir,
            os.pardir,
            os.pardir,
        )
    ),
)

# third-party libraries
ANDROID_PLATFORM_DEVELOPMENT_SCRIPTS_PATH = os.path.join(
    DIR_SOURCE_ROOT, 'third_party', 'android_platform', 'development', 'scripts'
)
BUILD_PATH = os.path.join(DIR_SOURCE_ROOT, 'build')
BUILD_UTIL_PATH = os.path.join(DIR_SOURCE_ROOT, 'build', 'util')

DEVIL_PATH = os.path.join(DIR_SOURCE_ROOT, 'third_party', 'catapult', 'devil')
JAVA_PATH = os.path.join(
    DIR_SOURCE_ROOT, 'third_party', 'jdk', 'current', 'bin'
)
TRACING_PATH = os.path.join(
    DIR_SOURCE_ROOT, 'third_party', 'catapult', 'tracing'
)


@contextlib.contextmanager
def SysPath(path, position=None):
    if position is None:
        sys.path.append(path)
    else:
        sys.path.insert(position, path)
    try:
        yield
    finally:
        if sys.path[-1] == path:
            sys.path.pop()
        else:
            sys.path.remove(path)


# Map of CPU architecture name to (toolchain_name, binprefix) pairs.
# TODO(digit): Use the build_vars.json file generated by gn.
_TOOL_ARCH_MAP = {
    'arm': ('arm-linux-androideabi-4.9', 'arm-linux-androideabi'),
    'arm64': ('aarch64-linux-android-4.9', 'aarch64-linux-android'),
    'x86': ('x86-4.9', 'i686-linux-android'),
    'x86_64': ('x86_64-4.9', 'x86_64-linux-android'),
    'x64': ('x86_64-4.9', 'x86_64-linux-android'),
    'mips': ('mipsel-linux-android-4.9', 'mipsel-linux-android'),
}

# Cache used to speed up the results of ToolPath()
# Maps (arch, tool_name) pairs to fully qualified program paths.
# Useful because ToolPath() is called repeatedly for demangling C++ symbols.
_cached_tool_paths = {}


def ToolPath(tool, cpu_arch):
    """Return a fully qualifed path to an arch-specific toolchain program.

    Args:
      tool: Unprefixed toolchain program name (e.g. 'objdump')
      cpu_arch: Target CPU architecture (e.g. 'arm64')
    Returns:
      Fully qualified path (e.g. ..../aarch64-linux-android-objdump')
    Raises:
      Exception if the toolchain could not be found.
    """
    tool_path = _cached_tool_paths.get((tool, cpu_arch))
    if tool_path:
        return tool_path

    toolchain_source, toolchain_prefix = _TOOL_ARCH_MAP.get(
        cpu_arch, (None, None)
    )
    if not toolchain_source:
        raise Exception('Could not find tool chain for ' + cpu_arch)

    toolchain_subdir = (
        'toolchains/%s/prebuilt/linux-x86_64/bin' % toolchain_source
    )

    tool_path = os.path.join(
        constants.ANDROID_NDK_ROOT,
        toolchain_subdir,
        toolchain_prefix + '-' + tool,
    )

    _cached_tool_paths[(tool, cpu_arch)] = tool_path
    return tool_path


def GetAaptPath():
    """Returns the path to the 'aapt' executable."""
    return os.path.join(constants.ANDROID_SDK_TOOLS, 'aapt')