#!/usr/bin/env python3
"""
Utility to interact with golden data test outputs, produced by golden data test framework.

For details on the golden data test framework see: docs/golden_data_test_framework.md.
"""

import json
import os
import pathlib
import platform
import re
import sys
import shutil

from subprocess import call, CalledProcessError, check_output, STDOUT, DEVNULL
import click

# Get relative imports to work when the package is not installed on the PYTHONPATH.
if __name__ == "__main__" and __package__ is None:
    sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

# pylint: disable=wrong-import-position
from buildscripts.util.fileops import read_yaml_file
# pylint: enable=wrong-import-position

assert sys.version_info >= (3, 7)


class AppError(Exception):
    """Application execution error."""

    pass


class GoldenTestConfig(object):
    """Represents the golden test configuration.

    See: docs/golden_data_test_framework.md#appendix---config-file-reference
    """

    def __init__(self, iterable=(), **kwargs):
        """Initialize the fields."""
        self.__dict__.update(iterable, **kwargs)

    outputRootPattern: str
    diffCmd: str

    @classmethod
    def from_yaml_file(cls, path: str) -> "GoldenTestConfig":
        """Read the golden test configuration from the given file."""
        return cls(**read_yaml_file(path))


class OutputPaths(object):
    """Represents actual and expected output paths."""

    def __init__(self, actual, expected):
        """Initialize the fields."""
        self.actual = actual
        self.expected = expected

    actual: None
    expected: None


def replace_variables(pattern: str, variables: dict) -> str:
    """Replace the mustache-style variables."""
    return re.sub(r"\{\{(\w+)\}\}", lambda match: variables[match.group(1)], pattern)


def get_path_name_regex(pattern: str) -> str:
    """Return the regex pattern for output names."""
    return '[0-9a-f]'.join([re.escape(part) for part in pattern.split('%')])


# For compatibility with version<3.8 that does not support shutil.copytree with dirs_exist_ok=True
def copytree_dirs_exist_ok_compatibility(src, dest):
    if os.path.isdir(src):
        if not os.path.isdir(dest):
            os.makedirs(dest)
        files = os.listdir(src)
        for file in files:
            copytree_dirs_exist_ok_compatibility(os.path.join(src, file), os.path.join(dest, file))
    else:
        shutil.copyfile(src, dest)


def copytree_dirs_exist_ok(src, dest):
    if sys.version_info >= (3, 8):
        shutil.copytree(src, dest, dirs_exist_ok=True)
    else:
        copytree_dirs_exist_ok_compatibility(src, dest)


@click.group()
@click.option('-n', '--dry-run', is_flag=True)
@click.option('-v', '--verbose', is_flag=True)
@click.option('--config', envvar='GOLDEN_TEST_CONFIG_PATH',
              help='Config file path. Also GOLDEN_TEST_CONFIG_PATH environment variable.')
@click.pass_context
def cli(ctx, dry_run, verbose, config):
    """Manage test results from golden data test framework.

    Allows for querying, diffing and accepting the golden data test results.

    \b
    For advanced setup guide see: https://wiki.corp.mongodb.com/display/KERNEL/Golden+Data+test+framework+and+workstation+setup
    """

    ctx.obj = GoldenTestApp(dry_run, verbose, config)


class GoldenTestApp(object):
    """Represents the golden application."""

    verbose: False
    dry_run: False
    config_path: None
    config: None
    output_parent_path = None
    output_name_pattern = None
    output_name_regex = None

    def __init__(self, dry_run, verbose, config_path):
        """Initialize the app."""
        self.verbose = verbose
        self.dry_run = dry_run
        self.config_path = config_path

    def init_config(self):
        self.config = self.load_config(self.config_path)

        self.output_parent_path = pathlib.Path(self.config.outputRootPattern).parent
        self.output_name_pattern = str(pathlib.Path(self.config.outputRootPattern).name)
        self.output_name_regex = get_path_name_regex(self.output_name_pattern)

    def vprint(self, *args, **kwargs):
        """Verbose print, if enabled."""
        if self.verbose:
            print(*args, file=sys.stderr, **kwargs)

    def call_shell(self, cmd):
        """Call shell command."""
        if not self.dry_run:
            call(cmd, shell=True)
        else:
            print(cmd)

    def get_git_root(self):
        """Return the root for git repo."""
        self.vprint("Querying git repo root")
        repo_root = check_output("git rev-parse --show-toplevel", shell=True, text=True).strip()
        self.vprint(f"Found git repo root: '{repo_root}'")
        return repo_root

    def load_config(self, config_path):
        """Load configuration file."""
        if config_path is None:
            raise AppError((
                "Can't load config. GOLDEN_TEST_CONFIG_PATH envrionment variable is not set. Golden test CLI must be configured before use.\n"
                "To configure it, follow the instructions in https://github.com/10gen/mongo/blob/master/docs/golden_data_test_framework.md#how-to-diff-and-accept-new-test-outputs-on-a-workstation\n"
                "Note: After setup you may need to rerun the tests for this utility to find them."))

        self.vprint(f"Loading config from path: '{config_path}'")
        config = GoldenTestConfig.from_yaml_file(config_path)

        if config.outputRootPattern is None:
            raise AppError("Invalid config. outputRootPattern config parameter is not set")

        return config

    def get_output_path(self, output_name):
        """Return the path for given output name."""
        if not re.match(self.output_name_regex, output_name):
            raise AppError(f"Invalid name: '{output_name}'. " +
                           f"Does not match configured pattern: {self.output_name_pattern}")
        output_path = os.path.join(self.output_parent_path, output_name)
        if not os.path.isdir(output_path):
            raise AppError(f"No such directory: '{output_path}'")
        return output_path

    def list_outputs(self):
        """Return names of all available outputs."""
        self.vprint(f"Listing outputs in path: '{self.output_parent_path}' " +
                    f"matching '{self.output_name_pattern}'")

        if not os.path.isdir(self.output_parent_path):
            return []
        return [
            o for o in os.listdir(self.output_parent_path) if re.match(self.output_name_regex, o)
            and os.path.isdir(os.path.join(self.output_parent_path, o))
        ]

    def get_latest_output(self):
        """Return the output name wit most recent created timestamp."""
        latest_name = None
        latest_ctime = None
        self.vprint("Searching for output with latest creation time")
        for output_name in self.list_outputs():
            stat = os.stat(self.get_output_path(output_name))
            if (latest_ctime is None) or (stat.st_ctime > latest_ctime):
                latest_name = output_name
                latest_ctime = stat.st_ctime

        if latest_name is None:
            raise AppError("No outputs found")

        self.vprint(f"Found output with latest creation time: {latest_name} " +
                    f"created at {latest_ctime}")

        return latest_name

    def get_paths(self, output_name):
        """Return actual and expected paths for given output name."""
        output_path = self.get_output_path(output_name)
        return OutputPaths(
            actual=os.path.join(output_path, "actual"), expected=os.path.join(
                output_path, "expected"))

    def setup_linux(self):
        # Create config file
        config_path = os.path.join(os.path.expanduser('~'), ".golden_test_config.yml")
        if not os.path.isfile(config_path):
            print(f"Creating {config_path}")
            config_contents = (
                r"""outputRootPattern: '/var/tmp/test_output/out-%%%%-%%%%-%%%%-%%%%'"""
                "\n"
                r"""diffCmd: 'git diff --no-index "{{expected}}" "{{actual}}"'"""
                "\n")
            with open(config_path, 'w') as file:
                file.write(config_contents)
        else:
            print(f"Skipping creating {config_path}, file exists.")

        # Add global GOLDEN_TEST_CONFIG_PATH environment variable
        etc_environment_path = "/etc/environment"
        env_var_defined = False
        if os.path.isfile(etc_environment_path):
            with open(etc_environment_path, 'r') as file:
                for line in file.readlines():
                    if line.startswith("GOLDEN_TEST_CONFIG_PATH="):
                        env_var_defined = True
        if not env_var_defined:
            print(f"Adding GOLDEN_TEST_CONFIG_PATH to {etc_environment_path}")
            env_var_contents = (f"GOLDEN_TEST_CONFIG_PATH=\"{config_path}\"")
            call(["sudo", "/bin/sh", "-c", f"echo '{env_var_contents}' >> {etc_environment_path}"])
        else:
            print(
                f"Skipping adding GOLDEN_TEST_CONFIG_PATH to {etc_environment_path}, variable already defined."
            )

    def setup_windows(self):
        # Create config file
        config_path = os.path.join(os.path.expandvars('%LocalAppData%'), ".golden_test_config.yml")
        if not os.path.isfile(config_path):
            print(f"Creating {config_path}")
            config_contents = (
                r"outputRootPattern: 'C:\Users\Administrator\AppData\Local\Temp\test_output\out-%%%%-%%%%-%%%%-%%%%'"
                "\n"
                r"""diffCmd: 'git diff --no-index "{{expected}}" "{{actual}}"'"""
                "\n")
            with open(config_path, 'w') as file:
                file.write(config_contents)
        else:
            print(f"Skipping creating {config_path}, file exists.")

        # Add global GOLDEN_TEST_CONFIG_PATH environment variable
        if os.environ.get("GOLDEN_TEST_CONFIG_PATH") is None:
            print("Setting GOLDEN_TEST_CONFIG_PATH global variable")
            call([
                "runas", "/profile", "/user:administrator",
                f"setx GOLDEN_TEST_CONFIG_PATH \"{config_path}\""
            ])
        else:
            print(
                "Skipping setting GOLDEN_TEST_CONFIG_PATH global variable, variable already defined."
            )

    @cli.command('diff', help='Diff the expected and actual folders of the test output')
    @click.argument('output_name', required=False)
    @click.pass_obj
    def command_diff(self, output_name):
        """Diff the expected and actual folders of the test output."""
        self.init_config()

        if output_name is None:
            output_name = self.get_latest_output()

        self.vprint(f"Diffing results from output '{output_name}'")

        paths = self.get_paths(output_name)
        diff_cmd = replace_variables(self.config.diffCmd,
                                     {'actual': paths.actual, 'expected': paths.expected})
        self.vprint(f"Running command: '{diff_cmd}'")
        self.call_shell(diff_cmd)

    @cli.command('get-path', help='Get the root folder path of the test output.')
    @click.argument('output_name', required=False)
    @click.pass_obj
    def command_get_path(self, output_name):
        """Get the root folder path of the test output."""
        self.init_config()

        if output_name is None:
            output_name = self.get_latest_output()

        print(self.get_output_path(output_name))

    @cli.command(
        'accept',
        help='Accept the actual test output and copy it as new golden data to the source repo.')
    @click.argument('output_name', required=False)
    @click.pass_obj
    def command_accept(self, output_name):
        """Accept the actual test output and copy it as new golden data to the source repo."""
        self.init_config()

        if output_name is None:
            output_name = self.get_latest_output()

        self.vprint(f"Accepting actual results from output '{output_name}'")

        repo_root = self.get_git_root()
        paths = self.get_paths(output_name)

        self.vprint(f"Copying files recursively from '{paths.actual}' to '{repo_root}'")
        if not self.dry_run:
            copytree_dirs_exist_ok(paths.actual, repo_root)

    @cli.command('clean', help='Remove all test outputs')
    @click.pass_obj
    def command_clean(self):
        """Remove all test outputs."""
        self.init_config()

        outputs = self.list_outputs()
        self.vprint(f"Deleting {len(outputs)} outputs")
        for output_name in outputs:
            output_path = self.get_output_path(output_name)
            self.vprint(f"Deleting folder: '{output_path}'")
            if not self.dry_run:
                shutil.rmtree(output_path)

    @cli.command('latest', help='Get the name of the most recent test output')
    @click.pass_obj
    def command_latest(self):
        """Get the name of the most recent test output."""
        self.init_config()

        output_name = self.get_latest_output()
        print(output_name)

    @cli.command('list', help='List all names of the available test outputs')
    @click.pass_obj
    def command_list(self):
        """List all names of the available test outputs."""
        self.init_config()

        for output_name in self.list_outputs():
            print(output_name)

    @cli.command('setup', help='Performs default setup based on current platform')
    @click.pass_obj
    def command_setup(self):
        """Performs default setup based on current platform."""
        if platform.platform().startswith("Linux"):
            self.setup_linux()
        elif platform.platform().startswith("Windows"):
            self.setup_windows()
        else:
            raise AppError(f"Platform not supported by this setup utility: {platform.platform()}")


def main():
    """Execute main."""
    try:
        cli()  # pylint: disable=no-value-for-parameter
    except AppError as err:
        print(err)
        sys.exit(1)


if __name__ == "__main__":
    main()