#!/usr/bin/env python3
#
# This file is part of the MicroPython project, http://micropython.org/
#
# The MIT License (MIT)
#
# Copyright (c) 2023 Jim Mussared
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

import ast, errno, hashlib, os, re, sys
from collections import namedtuple
from .mp_errno import MP_ERRNO_TABLE


def stdout_write_bytes(b):
    b = b.replace(b"\x04", b"")
    if hasattr(sys.stdout, "buffer"):
        sys.stdout.buffer.write(b)
        sys.stdout.buffer.flush()
    else:
        text = b.decode(sys.stdout.encoding, "strict")
        sys.stdout.write(text)


class TransportError(Exception):
    pass


class TransportExecError(TransportError):
    def __init__(self, status_code, error_output):
        self.status_code = status_code
        self.error_output = error_output
        super().__init__(error_output)


listdir_result = namedtuple("dir_result", ["name", "st_mode", "st_ino", "st_size"])


# Takes a Transport error (containing the text of an OSError traceback) and
# raises it as the corresponding OSError-derived exception.
def _convert_filesystem_error(e, info):
    if "OSError" in e.error_output:
        for code, estr in [
            *errno.errorcode.items(),
            (errno.EOPNOTSUPP, "EOPNOTSUPP"),
        ]:
            if estr in e.error_output:
                return OSError(code, info)

        # Some targets don't render OSError with the name of the errno, so in these
        # cases support an explicit mapping of errnos to known numeric codes.
        error_lines = e.error_output.splitlines()
        match = re.match(r"OSError: (\d+)$", error_lines[-1])
        if match:
            value = int(match.group(1), 10)
            if value in MP_ERRNO_TABLE:
                return OSError(MP_ERRNO_TABLE[value], info)

    return e


class Transport:
    def fs_listdir(self, src=""):
        buf = bytearray()

        def repr_consumer(b):
            buf.extend(b.replace(b"\x04", b""))

        cmd = "import os\nfor f in os.ilistdir(%s):\n print(repr(f), end=',')" % (
            ("'%s'" % src) if src else ""
        )
        try:
            buf.extend(b"[")
            self.exec(cmd, data_consumer=repr_consumer)
            buf.extend(b"]")
        except TransportExecError as e:
            raise _convert_filesystem_error(e, src) from None

        return [
            listdir_result(*f) if len(f) == 4 else listdir_result(*(f + (0,)))
            for f in ast.literal_eval(buf.decode())
        ]

    def fs_stat(self, src):
        try:
            self.exec("import os")
            return os.stat_result(self.eval("os.stat(%s)" % ("'%s'" % src)))
        except TransportExecError as e:
            raise _convert_filesystem_error(e, src) from None

    def fs_exists(self, src):
        try:
            self.fs_stat(src)
            return True
        except OSError:
            return False

    def fs_isdir(self, src):
        try:
            mode = self.fs_stat(src).st_mode
            return (mode & 0x4000) != 0
        except OSError:
            # Match CPython, a non-existent path is not a directory.
            return False

    def fs_printfile(self, src, chunk_size=256):
        cmd = (
            "with open('%s') as f:\n while 1:\n"
            "  b=f.read(%u)\n  if not b:break\n  print(b,end='')" % (src, chunk_size)
        )
        try:
            self.exec(cmd, data_consumer=stdout_write_bytes)
        except TransportExecError as e:
            raise _convert_filesystem_error(e, src) from None

    def fs_readfile(self, src, chunk_size=256, progress_callback=None):
        if progress_callback:
            src_size = self.fs_stat(src).st_size

        contents = bytearray()

        try:
            self.exec("f=open('%s','rb')\nr=f.read" % src)
            while True:
                chunk = self.eval("r({})".format(chunk_size))
                if not chunk:
                    break
                contents.extend(chunk)
                if progress_callback:
                    progress_callback(len(contents), src_size)
            self.exec("f.close()")
        except TransportExecError as e:
            raise _convert_filesystem_error(e, src) from None

        return contents

    def fs_writefile(self, dest, data, chunk_size=256, progress_callback=None):
        if progress_callback:
            src_size = len(data)
            written = 0

        try:
            self.exec("f=open('%s','wb')\nw=f.write" % dest)
            while data:
                chunk = data[:chunk_size]
                self.exec("w(" + repr(chunk) + ")")
                data = data[len(chunk) :]
                if progress_callback:
                    written += len(chunk)
                    progress_callback(written, src_size)
            self.exec("f.close()")
        except TransportExecError as e:
            raise _convert_filesystem_error(e, dest) from None

    def fs_mkdir(self, path):
        try:
            self.exec("import os\nos.mkdir('%s')" % path)
        except TransportExecError as e:
            raise _convert_filesystem_error(e, path) from None

    def fs_rmdir(self, path):
        try:
            self.exec("import os\nos.rmdir('%s')" % path)
        except TransportExecError as e:
            raise _convert_filesystem_error(e, path) from None

    def fs_rmfile(self, path):
        try:
            self.exec("import os\nos.remove('%s')" % path)
        except TransportExecError as e:
            raise _convert_filesystem_error(e, path) from None

    def fs_touchfile(self, path):
        try:
            self.exec("f=open('%s','a')\nf.close()" % path)
        except TransportExecError as e:
            raise _convert_filesystem_error(e, path) from None

    def fs_hashfile(self, path, algo, chunk_size=256):
        try:
            self.exec("import hashlib\nh = hashlib.{algo}()".format(algo=algo))
        except TransportExecError:
            # hashlib (or hashlib.{algo}) not available on device. Do the hash locally.
            data = self.fs_readfile(path, chunk_size=chunk_size)
            return getattr(hashlib, algo)(data).digest()
        try:
            self.exec(
                "buf = memoryview(bytearray({chunk_size}))\nwith open('{path}', 'rb') as f:\n while True:\n  n = f.readinto(buf)\n  if n == 0:\n   break\n  h.update(buf if n == {chunk_size} else buf[:n])\n".format(
                    chunk_size=chunk_size, path=path
                )
            )
            return self.eval("h.digest()")
        except TransportExecError as e:
            raise _convert_filesystem_error(e, path) from None