from typing import Callable
from collections import defaultdict
from abc import ABC

from .context import CallContext
from .model import ModelMatcher
from .const import RESERVED_MODULES, RESERVED_SERVICES, TRIVIAL_SERVICES, MODULE_SERVICES, METHOD_SERVICES_GET

import eaapi


Handler = Callable[[CallContext], None]


class IController(ABC):
    _name: str

    def get_handler(self, ctx: CallContext) -> Handler | None:
        raise NotImplementedError

    def get_service_routes(self, ctx: CallContext | None) -> dict[str, str]:
        raise NotImplementedError

    def serviced_prefixes(self) -> list[str]:
        raise NotImplementedError


class Controller(IController):
    def __init__(self, server, endpoint="", matcher: None | ModelMatcher = None):
        from .server import EAMServer
        self._server: EAMServer = server
        server.controllers.append(self)

        import inspect
        caller = inspect.getmodule(inspect.stack()[1][0])
        assert caller is not None
        self._name = caller.__name__

        self._handlers: dict[
            tuple[str | None, str | None],
            list[tuple[ModelMatcher, Handler]]
        ] = defaultdict(lambda: [])
        self._endpoint = endpoint
        self._matcher = matcher

        self._services: set[tuple[ModelMatcher, str]] = set()

        self._pre_handler: list[Callable[[CallContext, Handler], Handler]] = []

    @property
    def server(self):
        return self._server

    def on_pre(self, callback):
        if callback not in self._pre_handler:
            self._pre_handler.append(callback)

    def add_dummy_service(
        self,
        service: str,
        matcher: ModelMatcher | None = None,
        unsafe_force_bypass_reserved: bool = False
    ):
        if not unsafe_force_bypass_reserved:
            if service in RESERVED_SERVICES:
                raise KeyError(
                    f"{service} is a reserved service provided by default.\n"
                    "Pass unsafe_force_bypass_reserved=True to override this implementation"
                )
        if matcher is None:
            matcher = ModelMatcher()
        self._services.add((matcher, service))

    def register_handler(
        self,
        handler: Handler,
        module: str,
        method: str,
        matcher: ModelMatcher | None = None,
        service: str | None = None,
        unsafe_force_bypass_reserved: bool = False
    ):
        if not unsafe_force_bypass_reserved:
            if module in RESERVED_MODULES:
                raise KeyError(
                    f"{module} is a reserved module provided by default.\n"
                    "Pass unsafe_force_bypass_reserved=True to override this implementation"
                )

            if service is not None and service in RESERVED_SERVICES:
                raise KeyError(
                    f"{service} is a reserved service provided by default.\n"
                    "Pass unsafe_force_bypass_reserved=True to override this implementation"
                )

        if service is None:
            if module not in TRIVIAL_SERVICES:
                raise ValueError(f"Unable to identify service for {module}")
            service = module

        handlers = self._handlers[(module, method)]
        for i in handlers:
            if matcher is None and i[0] is None:
                raise ValueError(f"Duplicate default handler for {module}.{method}")
            if matcher == i[0]:
                raise ValueError(f"Duplicate handler for {module}.{method} ({matcher})")
        matcher_ = matcher or ModelMatcher()
        handlers.append((matcher_, handler))
        handlers.sort(key=lambda x: x[0])

        self._services.add((matcher_, service))

    def handler(
        self,
        module: str,
        method: str | None = None,
        matcher: ModelMatcher | None = None,
        service: str | None = None,
        unsafe_force_bypass_reserved: bool = False
    ):
        if method is None:
            def h2(method):
                return self.handler(module, method, matcher, service)
            return h2

        # Commented out for MachineCallContext bodge
        # def decorator(handler: Handler):
        def decorator(handler):
            self.register_handler(handler, module, method, matcher, service, unsafe_force_bypass_reserved)
            return handler
        return decorator

    def get_handler(self, ctx):
        if self._matcher is not None:
            if not self._matcher.matches(ctx.model):
                return None

        handlers = self._handlers[(ctx.module, ctx.method)]
        if not handlers:
            return None

        for matcher, handler in handlers:
            if matcher.matches(ctx.model):
                for i in self._pre_handler:
                    handler = i(ctx, handler)
                return handler

        return None

    def get_service_routes(self, ctx: CallContext | None):
        endpoint = self._server.expand_url(self._endpoint)

        if ctx is None:
            return {
                service: endpoint
                for _, service in self._services
            }

        if self._matcher is not None and not self._matcher.matches(ctx.model):
            return {}

        return {
            service: endpoint
            for matcher, service in self._services
            if matcher.matches(ctx.model)
        }

    def serviced_prefixes(self) -> list[str]:
        return [self._endpoint]


class ServicesController(IController):
    def __init__(self, server, services_mode: eaapi.const.ServicesMode):
        from .server import EAMServer
        self._server: EAMServer = server

        self.services_mode = services_mode

        self._name = __name__ + "." + self.__class__.__name__

    def service_routes_for(self, ctx: CallContext):
        services = defaultdict(lambda: self._server.public_url)
        for service, route in self._server.get_service_routes(ctx):
            services[service] = self._server.expand_url(route)

        return services

    def get_handler(self, ctx: CallContext) -> Handler | None:
        if ctx.module == MODULE_SERVICES and ctx.method == METHOD_SERVICES_GET:
            return self.services_get
        return None

    def service_route(self, for_service: str, ctx: CallContext):
        routes = self.service_routes_for(ctx)
        return routes[for_service]

    def services_get(self, ctx: CallContext):
        services = ctx.resp.append(
            MODULE_SERVICES, expire="600", mode=self.services_mode.value, status="0"
        )

        routes = self._server.get_service_routes(ctx)
        for service in routes:
            services.append("item", name=service, url=routes[service])

    def get_service_routes(self, ctx: CallContext | None) -> dict[str, str]:
        return {}

    def serviced_prefixes(self) -> list[str]:
        return [""]