#!/usr/bin/env python3

# SàT: an XMPP client
# Copyright (C) 2009-2020 Jérôme Poisson (goffi@goffi.org)

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.

# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import sys
import os
import tempfile
import string
import hashlib
import random
from pathlib import Path
from textwrap import dedent
import json
import pytest
from sh import jp


class JpJson:
    """jp like commands parsing result as JSON"""

    def __init__(self):
        self.subcommands = []

    def __call__(self, *args, **kwargs):
        args = self.subcommands + list(args)
        self.subcommands.clear()
        kwargs['output'] = 'json_raw'
        kwargs['_tty_out'] = False
        cmd = jp(*args, **kwargs)
        return json.loads(cmd.stdout)

    def __getattr__(self, name):
        if name.startswith('_'):
            # no jp subcommand starts with a "_",
            # and pytest uses some attributes with this name scheme
            return super().__getattr__(name)
        self.subcommands.append(name)
        return self


class JpElt(JpJson):
    """jp like commands parsing result as domishElement"""

    def __init__(self):
        super().__init__()
        from sat.tools.xml_tools import ElementParser
        self.parser = ElementParser()

    def __call__(self, *args, **kwargs):
        args = self.subcommands + list(args)
        self.subcommands.clear()
        kwargs['output'] = 'xml_raw'
        kwargs['_tty_out'] = False
        cmd = jp(*args, **kwargs)
        return self.parser(cmd.stdout.decode().strip())


class Editor:

    def __init__(self):
        # temporary directory will be deleted Automatically when this object will be
        # destroyed
        self.tmp_dir_obj = tempfile.TemporaryDirectory(prefix="sat_e2e_test_editor_")
        self.tmp_dir_path = Path(self.tmp_dir_obj.name)
        if not sys.executable:
            raise Exception("Can't find python executable")
        self.editor_set = False
        self.editor_path = self.tmp_dir_path / "editor.py"
        self.ori_content_path = self.tmp_dir_path / "original_content"
        self.new_content_path = self.tmp_dir_path / "new_content"
        self.base_script = dedent(f"""\
            #!{sys.executable}
            import sys

            def content_filter(content):
                return {{content_filter}}

            with open(sys.argv[1], 'r+') as f:
                original_content = f.read()
                f.seek(0)
                new_content = content_filter(original_content)
                f.write(new_content)
                f.truncate()

            with open("{self.ori_content_path}", "w") as f:
                f.write(original_content)

            with open("{self.new_content_path}", "w") as f:
                f.write(new_content)
            """
        )
        self._env = os.environ.copy()
        self._env["EDITOR"] = str(self.editor_path)

    def set_filter(self, content_filter: str = "content"):
        """Python code to modify original content

        The code will be applied to content received by editor.
        The original content received by editor is in the "content" variable.
        If filter_ is not specified, original content is written unmodified.
        Code must be on a single line.
        """
        if '\n' in content_filter:
            raise ValueError("new lines can't be used in filter_")
        with self.editor_path.open('w') as f:
            f.write(self.base_script.format(content_filter=content_filter))
        self.editor_path.chmod(0o700)
        self.editor_set = True

    @property
    def env(self):
        """Get environment variable with the editor set"""
        if not self.editor_set:
            self.set_filter()
        return self._env

    @property
    def original_content(self):
        """Last content received by editor, before any modification

        returns None if editor has not yet been called
        """
        try:
            with self.ori_content_path.open() as f:
                return f.read()
        except FileNotFoundError:
            return None

    @property
    def new_content(self):
        """Last content writen by editor

        This is the final content, after filter has been applied to original content
        returns None if editor has not yet been called
        """
        try:
            with self.new_content_path.open() as f:
                return f.read()
        except FileNotFoundError:
            return None


class FakeFile:
    ALPHABET = f"{string.ascii_letters}{string.digits}_"
    BUF_SIZE = 65535

    def __init__(self):
        self.tmp_dir_obj = tempfile.TemporaryDirectory(prefix="sat_e2e_test_files_")
        self.tmp_dir_path = Path(self.tmp_dir_obj.name)
        self.source_files = self.tmp_dir_path / "source"
        self.source_files.mkdir()
        self.dest_files = self.tmp_dir_path / "dest"
        self.dest_files.mkdir()
        self.hashes = {}

    @property
    def dest_path(self):
        """Path of a directory where files can be received

        The directory will be deleted at the end of session.
        Files from other test can be present, be sure to create a unique subdirectory or
        to use a unique destination file name
        """
        return self.dest_files

    def new_dest_file(self) -> Path:
        """Path to a randomly named destination file

        The file will be in self.dest_path.
        The file should be deleted after use. If not, it will be deleted at the end of
        session with the whole temporary test files directory.
        """
        name = ''.join(random.choices(self.ALPHABET, k=8))
        return self.dest_files / name

    def size(self, size: int, use_cache: bool = True):
        """Create a file of requested size, and returns its path

        @param use_cache: if True and a file of this size already exists, it is re-used
        """
        dest_path = self.source_files / str(size)
        if not use_cache or not dest_path.exists():
            hash_ = hashlib.sha256()
            remaining = size
            with dest_path.open('wb') as f:
                while remaining:
                    if remaining > self.BUF_SIZE:
                        to_get = self.BUF_SIZE
                    else:
                        to_get = remaining
                    buf = os.urandom(to_get)
                    f.write(buf)
                    hash_.update(buf)
                    remaining -= to_get
            self.hashes[dest_path] = hash_.hexdigest()
        return dest_path

    def get_source_hash(self, source_file: Path) -> str:
        """Retrieve hash calculated for a generated source file"""
        return self.hashes[source_file]

    def get_dest_hash(self, dest_file: Path) -> str:
        """Calculate hash of file at given path"""
        hash_ = hashlib.sha256()
        with dest_file.open('rb') as f:
            while True:
                buf = f.read(self.BUF_SIZE)
                if not buf:
                    break
                hash_.update(buf)
        return hash_.hexdigest()


@pytest.fixture(scope="session")
def jp_json():
    """Run jp with "json_raw" output, and returns the parsed value"""
    return JpJson()


@pytest.fixture(scope="session")
def jp_elt():
    """Run jp with "xml_raw" output, and returns the parsed value"""
    return JpElt()


@pytest.fixture(scope="session")
def test_profiles():
    """Test accounts created using in-band registration

    They will be removed at the end of session.
    The number of account per servers is set in the "accounts_by_servers" dict.
    Jids are in the form "account[x]@server[y].test".
    The profiles used are in the form "account[x]" for server1.test, and
    "account[x]_s[y]" for other servers.
    Password is "test" for all profiles and XMPP accounts.
    "account1" is connected and set as default profile
    Profiles created are returned as a tuple
    """
    profiles = []
    nb_servers = 3
    accounts_by_servers = {
        1: 1,
        2: 1,
        3: 0,
    }
    for server_idx in range(1, nb_servers+1):
        account_stop = accounts_by_servers[server_idx] + 1
        for account_idx in range(1, account_stop):
            profile_suff = f"_s{server_idx}" if server_idx>1 else ""
            profile = f"account{account_idx}{profile_suff}"
            profiles.append(profile)
            jp.account.create(
                f"account{account_idx}@server{server_idx}.test",
                "test",
                profile=profile,
                host=f"server{server_idx}.test"
            )
    jp.profile.modify(profile="account1", default=True, connect=True)
    jp.profile.connect(profile="account1_s2", connect=True)
    yield tuple(profiles)
    for profile in profiles:
        jp.account.delete(profile=profile, connect=True, force=True)
        jp.profile.delete(profile, force=True)


@pytest.fixture(scope="class")
def pubsub_nodes(test_profiles):
    """Create 2 testing nodes

    Both nodes will be created with "account1" profile, named "test" and have and "open"
    access model.
    One node will account1's PEP, the other one on pubsub.server1.test.
    """
    jp.pubsub.node.create(
        "-f", "access_model", "open",
        node="test",
        profile="account1", connect=True
    )
    jp.pubsub.node.create(
        "-f", "access_model", "open",
        service="pubsub.server1.test", node="test",
        profile="account1"
    )
    yield
    jp.pubsub.node.delete(
        node="test",
        profile="account1", connect=True,
        force=True
    )
    jp.pubsub.node.delete(
        service="pubsub.server1.test", node="test",
        profile="account1",
        force=True
    )


@pytest.fixture()
def editor():
    """Create a fake editor to automatise edition from CLI"""
    return Editor()


@pytest.fixture(scope="session")
def fake_file():
    """Manage dummy files creation and destination path"""
    return FakeFile()