"""
whatsapp.bindings
~~~~~~~~~~~~~~~~~~~~~~
Chat Context and Binding Client for wasup.py.

:copyright: (c) 2025-present June
:license: MIT, see LICENSE for more details.
"""

import logging
import re
from typing import TYPE_CHECKING, Any, Callable, Union

from whatsapp.messages import (
    AudioMessage,
    DocumentMessage,
    ImageMessage,
    InteractiveButtonMessage,
    InteractiveListMessage,
    InteractiveUrlMessage,
    ReactionMessage,
    StickerMessage,
    TextMessage,
    VideoMessage,
)

logger = logging.getLogger(__name__)

# Covers main Unicode emoji ranges: emoticons, misc symbols, dingbats, transport,
# supplemental symbols, regional indicators, and variation selectors.
EMOJI_PATTERN = re.compile(
    "["
    "\U0001f600-\U0001f64f"  # emoticons
    "\U0001f300-\U0001f5ff"  # misc symbols and pictographs
    "\U0001f680-\U0001f6ff"  # transport and map
    "\U0001f1e0-\U0001f1ff"  # regional indicator (flags)
    "\U00002600-\U000027bf"  # misc symbols, dingbats
    "\U0001f900-\U0001f9ff"  # supplemental symbols
    "\U0001fa00-\U0001fa6f"  # chess, health
    "\U0001fa70-\U0001faff"  # symbols and pictographs extended-A
    "\U00002702-\U000027b0"  # dingbats
    "]+",
    flags=re.UNICODE,
)

__all__ = ["BaseBindingClient", "ChatContext", "EMOJI_PATTERN"]

if TYPE_CHECKING:
    from whatsapp.bindings.azure.models import MediaContent  # base model class soon

    from .. import Bot


class BaseBindingClient:
    """
    Abstract base class for binding clients.

    Provides a standard interface for connecting WhatsApp messaging platforms
    (e.g., Azure ACS) to the wasup.py bot. Handles event processing, message routing,
    and session management.
    """

    def __init__(
        self,
        ctx: "Bot",
        client: Callable[[Any], Any],
        route: str = "/api/events",
    ):
        """
        Initialize the binding client.

        Args:
            ctx: The Bot instance.
            client: The platform-specific client (e.g., NotificationMessagesClient for Azure).
            route: HTTP route for receiving webhook events. Defaults to "/api/events".
        """
        self.ctx = ctx
        self.inactivity_manager = ctx.inactivity_manager
        self.session_store = ctx.session_store
        self.client = client
        self.route = route
        self.message = self.MessageHandler(self.client)

    # --- Event Handling ---
    async def process_event(self, req: Any) -> Any:
        """
        Process incoming events from the messaging platform.

        Should be implemented by subclasses to handle platform-specific event formats.

        Args:
            req: The request object containing event data.

        Returns:
            Response data to send back to the platform.
        """
        # 1. process event based on given API
        # 2. call internal event processor
        pass

    async def _process_message(self, events: Any) -> Any:
        """
        Process individual message events.

        Should be implemented by subclasses to handle:
        - Create chat context
        - Retrieve session
        - Build dialog context
        - Run dialog logic
        - Handle session persistence

        Args:
            events: The message event(s) to process.
        """
        # 1. create chat context
        # 2. retieve session
        # 3. build dialog context
        # 4. run dialog logic
        # 5. handle session persistance
        pass

    async def _step_accepts_media(self, from_id: str, media_type: str, stored_stack: list = None) -> bool:
        """Check if the current dialog step accepts the given media type.

        Inspects the active dialog's current step for the @Dialog.accept_media
        decorator. Returns True if the step declares acceptance of `media_type`,
        or if it accepts all types (empty list). Returns False if the step has no
        media acceptance or no active dialog is found.

        Shared by all binding implementations so Meta, Amazon, and other future
        adapters can reuse this without duplicating logic.

        Args:
            from_id: The user ID.
            media_type: The incoming media type string (e.g. "image", "document").
            stored_stack: Already-fetched session stack (avoids a second DB call).

        Returns:
            True if the active step accepts this media type.
        """
        if stored_stack is None:
            stored_stack = await self.session_store.get(from_id)
        if not stored_stack:
            return False

        active = stored_stack[-1]
        dialog_cls = self.ctx.dialog_registry.get(active["id"])
        if not dialog_cls:
            return False

        media_steps = getattr(dialog_cls, "_media_steps", {})
        if not media_steps:
            return False

        state = active.get("state", {})
        step_index = state.get("step_index", 0) + 1  # resume_dialog increments before running
        steps = getattr(dialog_cls, "_steps", [])
        if step_index >= len(steps):
            return False

        step_name = steps[step_index].__name__
        if step_name not in media_steps:
            return False

        accepted_types = media_steps[step_name]
        # empty list means accept all types
        return len(accepted_types) == 0 or media_type in accepted_types

    async def download_media(self, media: None, path: None) -> bytes:
        """Download media content by ID.

        This is a stub for type hinting. Subclasses should implement actual media
        downloading for their specific platform.

        Args:
            media: The MediaContent object containing media metadata.a to download.
            path: Optional file path to save the downloaded media. If not provided, media will be returned as bytes.
        """
        pass

    # --- Callable ---
    async def run(self):
        """
        Run the binding client (to be implemented by subclasses).

        Should start the web server and begin listening for incoming events
        from the messaging platform.
        """
        pass

    # --- Message Wrappers ---
    class MessageHandler:
        """
        Message handler for parsing and sending messages through the binding client.

        Provides methods to convert message objects into platform-specific formats
        and send them through the messaging platform.
        """

        def __init__(self, client: Any):
            """
            Initialize the message handler.

            Args:
                client: The platform-specific client for sending messages.
            """
            self.client = client

        async def parse_message(
            self,
            msg: Union[
                TextMessage,
                ImageMessage,
                DocumentMessage,
                VideoMessage,
                AudioMessage,
                StickerMessage,
                ReactionMessage,
                InteractiveListMessage,
                InteractiveButtonMessage,
                InteractiveUrlMessage,
            ],
        ) -> Any:
            """
            Parse message objects into platform-specific notification content.

            This is a stub for type hinting. Subclasses should implement message parsing
            for their specific platform (e.g., Azure ACS, AWS, etc.).

            Args:
                msg: The message object to parse (any supported message type).

            Returns:
                Platform-specific notification content.

            Raises:
                ValueError: If the message type is not supported.
            """
            message_type = type(msg).__name__  # using this as match/case checks patterns in order
            # since each message_type is inherited from TextMessage
            match msg:
                case "TextMessage":
                    # Parse text message
                    pass
                case "ImageMessage":
                    # Parse image message
                    pass
                case "DocumentMessage":
                    # Parse document message
                    pass
                case "VideoMessage":
                    # Parse video message
                    pass
                case "AudioMessage":
                    # Parse audio message
                    pass
                case "StickerMessage":
                    # Parse sticker message
                    pass
                case "ReactionMessage":
                    # Parse reaction message
                    pass
                case "InteractiveListMessage":
                    # Parse interactive list message
                    pass
                case "InteractiveButtonMessage":
                    # Parse interactive button message
                    pass
                case "InteractiveUrlMessage":
                    # Parse interactive URL message
                    pass
                case _:
                    raise ValueError(f"Unsupported message type: {message_type}")

        async def send_message(
            self,
            message: Union[
                TextMessage,
                ImageMessage,
                DocumentMessage,
                VideoMessage,
                AudioMessage,
                StickerMessage,
                ReactionMessage,
                InteractiveListMessage,
                InteractiveButtonMessage,
                InteractiveUrlMessage,
            ],
        ) -> Any:
            """
            Send a message through the messaging platform.

            This is a stub for type hinting. Subclasses should implement actual message sending
            for their specific platform.

            Args:
                message: The message object to send (any supported message type).

            Returns:
                Platform-specific response from sending the message.

            Raises:
                ValueError: If the message type is not supported.
            """
            match message:
                case TextMessage():
                    # Send text message
                    pass
                case ImageMessage():
                    # Send image message
                    pass
                case DocumentMessage():
                    # Send document message
                    pass
                case VideoMessage():
                    # Send video message
                    pass
                case AudioMessage():
                    # Send audio message
                    pass
                case StickerMessage():
                    # Send sticker message
                    pass
                case ReactionMessage():
                    # Send reaction message
                    pass
                case InteractiveListMessage():
                    # Send interactive list message
                    pass
                case InteractiveButtonMessage():
                    # Send interactive button message
                    pass
                case InteractiveUrlMessage():
                    # Send interactive URL message
                    pass
                case _:
                    raise ValueError(f"Unsupported message type: {type(message)}")


class ChatContext:
    """
    Represents the context of a chat session.

    Encapsulates information about a specific conversation including the user ID,
    channel ID, and recent message history. Used by bindings and message handlers
    to maintain conversation state.
    """

    def __init__(
        self,
        client: BaseBindingClient,
        channel_id: str,
        from_id: str,
        to: str,
        message_id: str,
        last_incoming_text: str = None,
        _retrieval_time_ns: int = None,
        incoming_media: "MediaContent | None" = None,
    ):
        """
        Initialize a chat context.

        Args:
            client: The binding client managing this chat session.
            channel_id: The channel/phone number ID for this conversation.
            from_id: The user ID (phone number) sending the message.
            to: The recipient ID (phone number).
            message_id: The ID of the last incoming message.
            last_incoming_text: Optional text content of the last incoming message.
            _retrieval_time_ns: Internal timestamp for message retrieval (in nanoseconds).
        """
        self.client = client
        self.channel_id = channel_id
        self.from_id = from_id
        self.to = to

        # TODO: create class for last message
        self.last_message_id = message_id
        self.last_incoming_text = last_incoming_text
        self.incoming_media = incoming_media

        self._retrieval_time_ns = _retrieval_time_ns
