# Copyright (c) 2023 Kyle Schouviller (https://github.com/kyle0654)

from abc import ABC, abstractmethod
import argparse
from typing import Any, Callable, Iterable, Literal, get_args, get_origin, get_type_hints
from pydantic import BaseModel, Field

from ..invocations.image import ImageField
from ..services.graph import GraphExecutionState
from ..services.invoker import Invoker


def add_parsers(
    subparsers,
    commands: list[type],
    command_field: str = "type",
    exclude_fields: list[str] = ["id", "type"],
    add_arguments: Callable[[argparse.ArgumentParser], None]|None = None
    ):
    """Adds parsers for each command to the subparsers"""

    # Create subparsers for each command
    for command in commands:
        hints = get_type_hints(command)
        cmd_name = get_args(hints[command_field])[0]
        command_parser = subparsers.add_parser(cmd_name, help=command.__doc__)

        if add_arguments is not None:
            add_arguments(command_parser)

        # Convert all fields to arguments
        fields = command.__fields__ # type: ignore
        for name, field in fields.items():
            if name in exclude_fields:
                continue

            if get_origin(field.type_) == Literal:
                allowed_values = get_args(field.type_)
                allowed_types = set()
                for val in allowed_values:
                    allowed_types.add(type(val))
                allowed_types_list = list(allowed_types)
                field_type = allowed_types_list[0] if len(allowed_types) == 1 else Union[allowed_types_list]  # type: ignore

                command_parser.add_argument(
                    f"--{name}",
                    dest=name,
                    type=field_type,
                    default=field.default,
                    choices=allowed_values,
                    help=field.field_info.description,
                )
            else:
                command_parser.add_argument(
                    f"--{name}",
                    dest=name,
                    type=field.type_,
                    default=field.default,
                    help=field.field_info.description,
                )


class CliContext:
    invoker: Invoker
    session: GraphExecutionState
    parser: argparse.ArgumentParser
    defaults: dict[str, Any]

    def __init__(self, invoker: Invoker, session: GraphExecutionState, parser: argparse.ArgumentParser):
        self.invoker = invoker
        self.session = session
        self.parser = parser
        self.defaults = dict()

    def get_session(self):
        self.session = self.invoker.services.graph_execution_manager.get(self.session.id)
        return self.session


class ExitCli(Exception):
    """Exception to exit the CLI"""
    pass


class BaseCommand(ABC, BaseModel):
    """A CLI command"""

    # All commands must include a type name like this:
    # type: Literal['your_command_name'] = 'your_command_name'

    @classmethod
    def get_all_subclasses(cls):
        subclasses = []
        toprocess = [cls]
        while len(toprocess) > 0:
            next = toprocess.pop(0)
            next_subclasses = next.__subclasses__()
            subclasses.extend(next_subclasses)
            toprocess.extend(next_subclasses)
        return subclasses

    @classmethod
    def get_commands(cls):
        return tuple(BaseCommand.get_all_subclasses())

    @classmethod
    def get_commands_map(cls):
        # Get the type strings out of the literals and into a dictionary
        return dict(map(lambda t: (get_args(get_type_hints(t)['type'])[0], t),BaseCommand.get_all_subclasses()))

    @abstractmethod
    def run(self, context: CliContext) -> None:
        """Run the command. Raise ExitCli to exit."""
        pass


class ExitCommand(BaseCommand):
    """Exits the CLI"""
    type: Literal['exit'] = 'exit'

    def run(self, context: CliContext) -> None:
        raise ExitCli()


class HelpCommand(BaseCommand):
    """Shows help"""
    type: Literal['help'] = 'help'

    def run(self, context: CliContext) -> None:
        context.parser.print_help()


def get_graph_execution_history(
    graph_execution_state: GraphExecutionState,
) -> Iterable[str]:
    """Gets the history of fully-executed invocations for a graph execution"""
    return (
        n
        for n in reversed(graph_execution_state.executed_history)
        if n in graph_execution_state.graph.nodes
    )


def get_invocation_command(invocation) -> str:
    fields = invocation.__fields__.items()
    type_hints = get_type_hints(type(invocation))
    command = [invocation.type]
    for name, field in fields:
        if name in ["id", "type"]:
            continue

        # TODO: add links

        # Skip image fields when serializing command
        type_hint = type_hints.get(name) or None
        if type_hint is ImageField or ImageField in get_args(type_hint):
            continue

        field_value = getattr(invocation, name)
        field_default = field.default
        if field_value != field_default:
            if type_hint is str or str in get_args(type_hint):
                command.append(f'--{name} "{field_value}"')
            else:
                command.append(f"--{name} {field_value}")

    return " ".join(command)


class HistoryCommand(BaseCommand):
    """Shows the invocation history"""
    type: Literal['history'] = 'history'

    # Inputs
    # fmt: off
    count: int = Field(default=5, gt=0, description="The number of history entries to show")
    # fmt: on

    def run(self, context: CliContext) -> None:
        history = list(get_graph_execution_history(context.get_session()))
        for i in range(min(self.count, len(history))):
            entry_id = history[-1 - i]
            entry = context.get_session().graph.get_node(entry_id)
            print(f"{entry_id}: {get_invocation_command(entry)}")


class SetDefaultCommand(BaseCommand):
    """Sets a default value for a field"""
    type: Literal['default'] = 'default'

    # Inputs
    # fmt: off
    field: str = Field(description="The field to set the default for")
    value: str = Field(description="The value to set the default to, or None to clear the default")
    # fmt: on

    def run(self, context: CliContext) -> None:
        if self.value is None:
            if self.field in context.defaults:
                del context.defaults[self.field]
        else:
            context.defaults[self.field] = self.value