# SPDX-License-Identifier: GPL-2.0+
#
# Copyright (c) 2016 Google, Inc
#

import glob
import os
import shutil
import struct
import sys
import tempfile

from patman import command
from patman import tout

# Output directly (generally this is temporary)
outdir = None

# True to keep the output directory around after exiting
preserve_outdir = False

# Path to the Chrome OS chroot, if we know it
chroot_path = None

# Search paths to use for Filename(), used to find files
search_paths = []

tool_search_paths = []

# Tools and the packages that contain them, on debian
packages = {
    'lz4': 'liblz4-tool',
    }

# List of paths to use when looking for an input file
indir = []

def PrepareOutputDir(dirname, preserve=False):
    """Select an output directory, ensuring it exists.

    This either creates a temporary directory or checks that the one supplied
    by the user is valid. For a temporary directory, it makes a note to
    remove it later if required.

    Args:
        dirname: a string, name of the output directory to use to store
                intermediate and output files. If is None - create a temporary
                directory.
        preserve: a Boolean. If outdir above is None and preserve is False, the
                created temporary directory will be destroyed on exit.

    Raises:
        OSError: If it cannot create the output directory.
    """
    global outdir, preserve_outdir

    preserve_outdir = dirname or preserve
    if dirname:
        outdir = dirname
        if not os.path.isdir(outdir):
            try:
                os.makedirs(outdir)
            except OSError as err:
                raise CmdError("Cannot make output directory '%s': '%s'" %
                                (outdir, err.strerror))
        tout.Debug("Using output directory '%s'" % outdir)
    else:
        outdir = tempfile.mkdtemp(prefix='binman.')
        tout.Debug("Using temporary directory '%s'" % outdir)

def _RemoveOutputDir():
    global outdir

    shutil.rmtree(outdir)
    tout.Debug("Deleted temporary directory '%s'" % outdir)
    outdir = None

def FinaliseOutputDir():
    global outdir, preserve_outdir

    """Tidy up: delete output directory if temporary and not preserved."""
    if outdir and not preserve_outdir:
        _RemoveOutputDir()
        outdir = None

def GetOutputFilename(fname):
    """Return a filename within the output directory.

    Args:
        fname: Filename to use for new file

    Returns:
        The full path of the filename, within the output directory
    """
    return os.path.join(outdir, fname)

def GetOutputDir():
    """Return the current output directory

    Returns:
        str: The output directory
    """
    return outdir

def _FinaliseForTest():
    """Remove the output directory (for use by tests)"""
    global outdir

    if outdir:
        _RemoveOutputDir()
        outdir = None

def SetInputDirs(dirname):
    """Add a list of input directories, where input files are kept.

    Args:
        dirname: a list of paths to input directories to use for obtaining
                files needed by binman to place in the image.
    """
    global indir

    indir = dirname
    tout.Debug("Using input directories %s" % indir)

def GetInputFilename(fname, allow_missing=False):
    """Return a filename for use as input.

    Args:
        fname: Filename to use for new file
        allow_missing: True if the filename can be missing

    Returns:
        fname, if indir is None;
        full path of the filename, within the input directory;
        None, if file is missing and allow_missing is True

    Raises:
        ValueError if file is missing and allow_missing is False
    """
    if not indir or fname[:1] == '/':
        return fname
    for dirname in indir:
        pathname = os.path.join(dirname, fname)
        if os.path.exists(pathname):
            return pathname

    if allow_missing:
        return None
    raise ValueError("Filename '%s' not found in input path (%s) (cwd='%s')" %
                     (fname, ','.join(indir), os.getcwd()))

def GetInputFilenameGlob(pattern):
    """Return a list of filenames for use as input.

    Args:
        pattern: Filename pattern to search for

    Returns:
        A list of matching files in all input directories
    """
    if not indir:
        return glob.glob(fname)
    files = []
    for dirname in indir:
        pathname = os.path.join(dirname, pattern)
        files += glob.glob(pathname)
    return sorted(files)

def Align(pos, align):
    if align:
        mask = align - 1
        pos = (pos + mask) & ~mask
    return pos

def NotPowerOfTwo(num):
    return num and (num & (num - 1))

def SetToolPaths(toolpaths):
    """Set the path to search for tools

    Args:
        toolpaths: List of paths to search for tools executed by Run()
    """
    global tool_search_paths

    tool_search_paths = toolpaths

def PathHasFile(path_spec, fname):
    """Check if a given filename is in the PATH

    Args:
        path_spec: Value of PATH variable to check
        fname: Filename to check

    Returns:
        True if found, False if not
    """
    for dir in path_spec.split(':'):
        if os.path.exists(os.path.join(dir, fname)):
            return True
    return False

def GetHostCompileTool(name):
    """Get the host-specific version for a compile tool

    This checks the environment variables that specify which version of
    the tool should be used (e.g. ${HOSTCC}).

    The following table lists the host-specific versions of the tools
    this function resolves to:

        Compile Tool  | Host version
        --------------+----------------
        as            |  ${HOSTAS}
        ld            |  ${HOSTLD}
        cc            |  ${HOSTCC}
        cpp           |  ${HOSTCPP}
        c++           |  ${HOSTCXX}
        ar            |  ${HOSTAR}
        nm            |  ${HOSTNM}
        ldr           |  ${HOSTLDR}
        strip         |  ${HOSTSTRIP}
        objcopy       |  ${HOSTOBJCOPY}
        objdump       |  ${HOSTOBJDUMP}
        dtc           |  ${HOSTDTC}

    Args:
        name: Command name to run

    Returns:
        host_name: Exact command name to run instead
        extra_args: List of extra arguments to pass
    """
    host_name = None
    extra_args = []
    if name in ('as', 'ld', 'cc', 'cpp', 'ar', 'nm', 'ldr', 'strip',
                'objcopy', 'objdump', 'dtc'):
        host_name, *host_args = env.get('HOST' + name.upper(), '').split(' ')
    elif name == 'c++':
        host_name, *host_args = env.get('HOSTCXX', '').split(' ')

    if host_name:
        return host_name, extra_args
    return name, []

def GetTargetCompileTool(name, cross_compile=None):
    """Get the target-specific version for a compile tool

    This first checks the environment variables that specify which
    version of the tool should be used (e.g. ${CC}). If those aren't
    specified, it checks the CROSS_COMPILE variable as a prefix for the
    tool with some substitutions (e.g. "${CROSS_COMPILE}gcc" for cc).

    The following table lists the target-specific versions of the tools
    this function resolves to:

        Compile Tool  | First choice   | Second choice
        --------------+----------------+----------------------------
        as            |  ${AS}         | ${CROSS_COMPILE}as
        ld            |  ${LD}         | ${CROSS_COMPILE}ld.bfd
                      |                |   or ${CROSS_COMPILE}ld
        cc            |  ${CC}         | ${CROSS_COMPILE}gcc
        cpp           |  ${CPP}        | ${CROSS_COMPILE}gcc -E
        c++           |  ${CXX}        | ${CROSS_COMPILE}g++
        ar            |  ${AR}         | ${CROSS_COMPILE}ar
        nm            |  ${NM}         | ${CROSS_COMPILE}nm
        ldr           |  ${LDR}        | ${CROSS_COMPILE}ldr
        strip         |  ${STRIP}      | ${CROSS_COMPILE}strip
        objcopy       |  ${OBJCOPY}    | ${CROSS_COMPILE}objcopy
        objdump       |  ${OBJDUMP}    | ${CROSS_COMPILE}objdump
        dtc           |  ${DTC}        | (no CROSS_COMPILE version)

    Args:
        name: Command name to run

    Returns:
        target_name: Exact command name to run instead
        extra_args: List of extra arguments to pass
    """
    env = dict(os.environ)

    target_name = None
    extra_args = []
    if name in ('as', 'ld', 'cc', 'cpp', 'ar', 'nm', 'ldr', 'strip',
                'objcopy', 'objdump', 'dtc'):
        target_name, *extra_args = env.get(name.upper(), '').split(' ')
    elif name == 'c++':
        target_name, *extra_args = env.get('CXX', '').split(' ')

    if target_name:
        return target_name, extra_args

    if cross_compile is None:
        cross_compile = env.get('CROSS_COMPILE', '')
    if not cross_compile:
        return name, []

    if name in ('as', 'ar', 'nm', 'ldr', 'strip', 'objcopy', 'objdump'):
        target_name = cross_compile + name
    elif name == 'ld':
        try:
            if Run(cross_compile + 'ld.bfd', '-v'):
                target_name = cross_compile + 'ld.bfd'
        except:
            target_name = cross_compile + 'ld'
    elif name == 'cc':
        target_name = cross_compile + 'gcc'
    elif name == 'cpp':
        target_name = cross_compile + 'gcc'
        extra_args = ['-E']
    elif name == 'c++':
        target_name = cross_compile + 'g++'
    else:
        target_name = name
    return target_name, extra_args

def Run(name, *args, **kwargs):
    """Run a tool with some arguments

    This runs a 'tool', which is a program used by binman to process files and
    perhaps produce some output. Tools can be located on the PATH or in a
    search path.

    Args:
        name: Command name to run
        args: Arguments to the tool
        for_host: True to resolve the command to the version for the host
        for_target: False to run the command as-is, without resolving it
                   to the version for the compile target

    Returns:
        CommandResult object
    """
    try:
        binary = kwargs.get('binary')
        for_host = kwargs.get('for_host', False)
        for_target = kwargs.get('for_target', not for_host)
        env = None
        if tool_search_paths:
            env = dict(os.environ)
            env['PATH'] = ':'.join(tool_search_paths) + ':' + env['PATH']
        if for_target:
            name, extra_args = GetTargetCompileTool(name)
            args = tuple(extra_args) + args
        elif for_host:
            name, extra_args = GetHostCompileTool(name)
            args = tuple(extra_args) + args
        name = os.path.expanduser(name)  # Expand paths containing ~
        all_args = (name,) + args
        result = command.RunPipe([all_args], capture=True, capture_stderr=True,
                                 env=env, raise_on_error=False, binary=binary)
        if result.return_code:
            raise Exception("Error %d running '%s': %s" %
               (result.return_code,' '.join(all_args),
                result.stderr))
        return result.stdout
    except:
        if env and not PathHasFile(env['PATH'], name):
            msg = "Please install tool '%s'" % name
            package = packages.get(name)
            if package:
                 msg += " (e.g. from package '%s')" % package
            raise ValueError(msg)
        raise

def Filename(fname):
    """Resolve a file path to an absolute path.

    If fname starts with ##/ and chroot is available, ##/ gets replaced with
    the chroot path. If chroot is not available, this file name can not be
    resolved, `None' is returned.

    If fname is not prepended with the above prefix, and is not an existing
    file, the actual file name is retrieved from the passed in string and the
    search_paths directories (if any) are searched to for the file. If found -
    the path to the found file is returned, `None' is returned otherwise.

    Args:
      fname: a string,  the path to resolve.

    Returns:
      Absolute path to the file or None if not found.
    """
    if fname.startswith('##/'):
      if chroot_path:
        fname = os.path.join(chroot_path, fname[3:])
      else:
        return None

    # Search for a pathname that exists, and return it if found
    if fname and not os.path.exists(fname):
        for path in search_paths:
            pathname = os.path.join(path, os.path.basename(fname))
            if os.path.exists(pathname):
                return pathname

    # If not found, just return the standard, unchanged path
    return fname

def ReadFile(fname, binary=True):
    """Read and return the contents of a file.

    Args:
      fname: path to filename to read, where ## signifiies the chroot.

    Returns:
      data read from file, as a string.
    """
    with open(Filename(fname), binary and 'rb' or 'r') as fd:
        data = fd.read()
    #self._out.Info("Read file '%s' size %d (%#0x)" %
                   #(fname, len(data), len(data)))
    return data

def WriteFile(fname, data, binary=True):
    """Write data into a file.

    Args:
        fname: path to filename to write
        data: data to write to file, as a string
    """
    #self._out.Info("Write file '%s' size %d (%#0x)" %
                   #(fname, len(data), len(data)))
    with open(Filename(fname), binary and 'wb' or 'w') as fd:
        fd.write(data)

def GetBytes(byte, size):
    """Get a string of bytes of a given size

    Args:
        byte: Numeric byte value to use
        size: Size of bytes/string to return

    Returns:
        A bytes type with 'byte' repeated 'size' times
    """
    return bytes([byte]) * size

def ToBytes(string):
    """Convert a str type into a bytes type

    Args:
        string: string to convert

    Returns:
        A bytes type
    """
    return string.encode('utf-8')

def ToString(bval):
    """Convert a bytes type into a str type

    Args:
        bval: bytes value to convert

    Returns:
        Python 3: A bytes type
        Python 2: A string type
    """
    return bval.decode('utf-8')

def Compress(indata, algo, with_header=True):
    """Compress some data using a given algorithm

    Note that for lzma this uses an old version of the algorithm, not that
    provided by xz.

    This requires 'lz4' and 'lzma_alone' tools. It also requires an output
    directory to be previously set up, by calling PrepareOutputDir().

    Args:
        indata: Input data to compress
        algo: Algorithm to use ('none', 'gzip', 'lz4' or 'lzma')

    Returns:
        Compressed data
    """
    if algo == 'none':
        return indata
    fname = GetOutputFilename('%s.comp.tmp' % algo)
    WriteFile(fname, indata)
    if algo == 'lz4':
        data = Run('lz4', '--no-frame-crc', '-B4', '-5', '-c', fname,
                   binary=True)
    # cbfstool uses a very old version of lzma
    elif algo == 'lzma':
        outfname = GetOutputFilename('%s.comp.otmp' % algo)
        Run('lzma_alone', 'e', fname, outfname, '-lc1', '-lp0', '-pb0', '-d8')
        data = ReadFile(outfname)
    elif algo == 'gzip':
        data = Run('gzip', '-c', fname, binary=True)
    else:
        raise ValueError("Unknown algorithm '%s'" % algo)
    if with_header:
        hdr = struct.pack('<I', len(data))
        data = hdr + data
    return data

def Decompress(indata, algo, with_header=True):
    """Decompress some data using a given algorithm

    Note that for lzma this uses an old version of the algorithm, not that
    provided by xz.

    This requires 'lz4' and 'lzma_alone' tools. It also requires an output
    directory to be previously set up, by calling PrepareOutputDir().

    Args:
        indata: Input data to decompress
        algo: Algorithm to use ('none', 'gzip', 'lz4' or 'lzma')

    Returns:
        Compressed data
    """
    if algo == 'none':
        return indata
    if with_header:
        data_len = struct.unpack('<I', indata[:4])[0]
        indata = indata[4:4 + data_len]
    fname = GetOutputFilename('%s.decomp.tmp' % algo)
    with open(fname, 'wb') as fd:
        fd.write(indata)
    if algo == 'lz4':
        data = Run('lz4', '-dc', fname, binary=True)
    elif algo == 'lzma':
        outfname = GetOutputFilename('%s.decomp.otmp' % algo)
        Run('lzma_alone', 'd', fname, outfname)
        data = ReadFile(outfname, binary=True)
    elif algo == 'gzip':
        data = Run('gzip', '-cd', fname, binary=True)
    else:
        raise ValueError("Unknown algorithm '%s'" % algo)
    return data

CMD_CREATE, CMD_DELETE, CMD_ADD, CMD_REPLACE, CMD_EXTRACT = range(5)

IFWITOOL_CMDS = {
    CMD_CREATE: 'create',
    CMD_DELETE: 'delete',
    CMD_ADD: 'add',
    CMD_REPLACE: 'replace',
    CMD_EXTRACT: 'extract',
    }

def RunIfwiTool(ifwi_file, cmd, fname=None, subpart=None, entry_name=None):
    """Run ifwitool with the given arguments:

    Args:
        ifwi_file: IFWI file to operation on
        cmd: Command to execute (CMD_...)
        fname: Filename of file to add/replace/extract/create (None for
            CMD_DELETE)
        subpart: Name of sub-partition to operation on (None for CMD_CREATE)
        entry_name: Name of directory entry to operate on, or None if none
    """
    args = ['ifwitool', ifwi_file]
    args.append(IFWITOOL_CMDS[cmd])
    if fname:
        args += ['-f', fname]
    if subpart:
        args += ['-n', subpart]
    if entry_name:
        args += ['-d', '-e', entry_name]
    Run(*args)

def ToHex(val):
    """Convert an integer value (or None) to a string

    Returns:
        hex value, or 'None' if the value is None
    """
    return 'None' if val is None else '%#x' % val

def ToHexSize(val):
    """Return the size of an object in hex

    Returns:
        hex value of size, or 'None' if the value is None
    """
    return 'None' if val is None else '%#x' % len(val)