import logging
import os
import sys
from pathlib import Path
import glob
from types import SimpleNamespace
from datetime import datetime
from pprint import pprint
import pkg_resources

import chromalog
import click
import toml

from . import core, plugin

# chromalog.basicConfig(level=os.environ.get("LOGLEVEL", "INFO"))

log = logging.getLogger("shepherd.cli")


def echo_heading(title, on_nl=True):
    if on_nl:
        click.echo("")
    click.echo(click.style(".: ", fg='blue', bold=True) +
               click.style(title, fg='white', bold=True) +
               click.style(" :.", fg='blue', bold=True))


def echo_section(title, input_text=None, on_nl=True):
    if on_nl:
        click.echo("")
    click.secho(":: ", bold=True, fg='blue', nl=False)
    click.secho(title, bold=True, nl=False)
    if input_text:
        click.secho(F" {input_text}", fg='green', bold=True, nl=False)
    click.echo("")


@click.group(invoke_without_command=True)
@click.option('-c', '--config', 'default_config_path',  type=click.Path(),
              help="Shepherd config TOML file to be used as default config layer."
              " Overrides default './shepherd*.toml' search")
@click.option('-l', '--local', 'local_operation', is_flag=True,
              help="Only use the local config layers (default and custom), and disable all"
              " Shepherd Control remote features")
@click.option('-d', '--default-config-only', 'only_default_layer', is_flag=True,
              help="Ignore the custom config layer (still uses the Control config above that)")
@click.option('-n', '--new-device-mode', 'new_device_mode', is_flag=True,
              help="Clear existing device identity and cached Shepherd Control config layer."
              " Also triggered by the presence of a shepherd.new file in the"
              " same directory as the custom config layer file.")
@click.pass_context
def cli(ctx, default_config_path, local_operation, only_default_layer, new_device_mode):
    """
    Core service. If default config file is not provided with '-c' option, the first filename
    in the current working directory beginning  with "shepherd" and
    ending with ".toml" will be used.
    """

    version_text = pkg_resources.get_distribution("shepherd")
    log.info(F"Shepherd Agent [{version_text}]")

    # Drop down to subcommand if it doesn't need default config file processing
    if ctx.invoked_subcommand == "template":
        return

    # Get a default config path to use
    if not default_config_path:
        default_config_path = sorted(glob.glob("./shepherd*.toml"))[:1]
        if default_config_path:
            default_config_path = default_config_path[0]
            log.info(F"No default config file provided, found {default_config_path}")
            with open(default_config_path, 'r+') as f:
                content = f.read()
                if "Compiled Shepherd config" in content:
                    log.warning("Default config file looks like it is full compiled config"
                                " file generated by Shepherd and picked up due to accidental"
                                " name match")
        else:
            log.error("No default config file provided, and no 'shepherd*.toml' could be"
                      " found in the current directory")
            sys.exit(1)

    # Establish what config layers we're going to try and use
    control_enabled = True
    use_custom_config = True

    if local_operation or (ctx.invoked_subcommand == "test"):
        control_enabled = False
        log.info("Running in local only mode")

    if only_default_layer:
        use_custom_config = False

    agent = core.Agent(default_config_path, use_custom_config, control_enabled, new_device_mode)
    ctx.ensure_object(SimpleNamespace)
    ctx.obj.agent = agent

    # Drop down to subcommands that needed a config compiled
    if ctx.invoked_subcommand == "test":
        return

    print(str(datetime.now()))

    agent.start()


@cli.command()
@click.argument('plugin_name', required=False)
@click.argument('interface_function', required=False)
@click.pass_context
def test(ctx, plugin_name, interface_function):
    agent = ctx.obj.agent
    plugin_configs = agent.applied_config.copy()
    del plugin_configs['shepherd']

    echo_heading("Shepherd - Test")

    if not plugin_name:
        log.info("Test initialisation of all plugins in config...")

        echo_section("Plugins loaded:")
        if len(plugin_configs) == 0:
            click.echo("---none---")
        for plugin_name, config in plugin_configs.items():
            click.secho(F" {plugin_name}", fg='green')

        echo_section("Core config:")
        print(toml.dumps(agent.core_config))
        # pprint(agent.core_config)

        echo_section("Plugin configs:")
        if len(plugin_configs) == 0:
            click.echo("---none---")
        for name, config in plugin_configs.items():
            click.secho(F" {plugin_name}", fg='green')
            print(toml.dumps(config))
            # pprint(config)

        click.echo("")

        log.info("Initialising plugins...")
        plugin.init_plugins(agent.applied_config)
        log.info("Plugin initialisation done")

        return

    echo_section("Target plugin:", input_text=plugin_name, on_nl=False)
    # TODO find plugin dependancies

    if plugin_name not in plugin_configs:
        log.error(F"Supplied plugin name '{plugin_name}' is not loaded"
                  " (not present in config)")
        sys.exit(1)

    echo_section(F"Config [{plugin_name}]:")
    print(toml.dumps(plugin_configs[plugin_name]))
    # pprint(plugin_configs[plugin_name])

    interface = plugin.load_plugin(plugin_name)

    if not interface_function:
        echo_section(F"Interface functions [{plugin_name}]:", on_nl=False)

        for name, func in interface._functions.items():
            click.echo(F" {name}")
        return

    echo_section("Target interface function:", input_text=interface_function,  on_nl=False)
    if interface_function not in interface._functions:
        log.error(F"Supplied interface function name '{interface_function}' is not present in"
                  F" plugin {plugin_name}")
        sys.exit(1)

    log.info("Initialising plugins...")
    # TODO Going to need to add 'shepherd' to this, so that its public plugin interface also gets
    # init - functions and hooks
    plugin.init_plugins({plugin_name: plugin_configs[plugin_name]})
    log.info("Plugin initialisation done")

    # TODO look for a spec on the interface function, and parse cmdline values if it's there

    print(interface._functions[interface_function]())


class BlankEncoder(toml.TomlEncoder):
    """
    A TOML encoder that emit empty keys (values of None). This isn't valid TOML,
    but is useful for generating templates.
    """
    class BlankValue:
        pass

    def __init__(self, _dict=dict, preserve=False):
        super().__init__(_dict, preserve)
        self.dump_funcs[self.BlankValue] = lambda v: ''

    def dump_sections(self, o, sup):
        for section in o:
            if o[section] is None:
                o[section] = self.BlankValue()
        return super().dump_sections(o, sup)

    def dump_value(self, v):
        if v is None:
            v = self.BlankValue()
        return super().dump_value(v)


@cli.command()
@click.argument('plugin_name', required=False)
@click.option('-a', '--include-all', is_flag=True,
              help="Include all optional fields in the template")
@click.option('-c', '--config', 'config_path',  type=click.Path(),
              help="Path to append or create config tempalate")
@click.option('-d', '--plugin-dir', type=click.Path(),
              help="Directory to search for plugin modules, in addition to built in Shepherd"
              " plugins and the global import path. Defaults to current directory.")
@click.pass_context
def template(ctx, plugin_name, include_all, config_path, plugin_dir):
    """
    Generate a template config TOML file for PLUGIN_NAME, or for the Shepherd core if
    PLUGIN_NAME is not provided.

    If config path is provided ("-c"), append to that file (if it exists) or write to
    a new file (if it doesn't yet exist).
    """

    echo_heading("Shepherd - Template")

    if not plugin_dir:
        plugin_dir = Path.cwd()

    confspec = None
    if not plugin_name:
        plugin_name = "shepherd"

    try:
        plugin_interface = plugin.load_plugin(plugin_name, plugin_dir)
    except plugin.PluginLoadError as e:
        log.error(e.args[0])
        sys.exit(1)
    confspec = plugin_interface.confspec

    template_dict = confspec.get_template(include_all)
    template_toml = toml.dumps({plugin_name: template_dict}, encoder=BlankEncoder())

    if include_all:
        log.info("Including all optional fields")
    else:
        log.info("Including required fields only")

    echo_section("Config template for", input_text=F"[{plugin_name}]")
    click.echo("")
    click.echo(template_toml)

    if not config_path:
        # reuse parent "-c" for convenience
        config_path = ctx.parent.params["default_config_path"]

    if not config_path:
        return

    if Path(config_path).is_file():
        try:
            existing_config = toml.load(config_path)
        except Exception:
            click.confirm(
                F"File {config_path} already exists and is not a valid TOML file. Overwrite?",
                default=True, abort=True)

            click.echo(F"Writing [{plugin_name}] template to {config_path}")
            with open(config_path, 'w+') as f:
                f.write(template_toml)
        else:
            if plugin_name in existing_config:
                click.confirm(F"Overwrite [{plugin_name}] section in {config_path}?",
                              default=True, abort=True)
                click.echo(F"Overwriting [{plugin_name}] section in {config_path}")
            else:
                click.confirm(F"Add [{plugin_name}] section to {config_path}?",
                              default=True, abort=True)
                click.echo(F"Adding [{plugin_name}] section to {config_path}")
            existing_config[plugin_name] = template_dict
            with open(config_path, 'w+') as f:
                f.write(toml.dumps(existing_config))
    else:
        click.echo(F"Writing [{plugin_name}] template to {config_path}")
        with open(config_path, 'w+') as f:
            f.write(template_toml)