from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session
from sqlalchemy import or_, and_, func
from typing import List
from app.db.base import get_db
from app.models.user import User, Connection
from app.models.message import (
    Conversation,
    Message,
    GroupChat,
    GroupChatMember,
    GroupMessage,
)
from app.schemas.message import (
    MessageCreate,
    MessageResponse,
    ConversationResponse,
    GroupChatCreate,
    GroupChatResponse,
    GroupMessageCreate,
    GroupMessageResponse,
)
from app.api.auth import get_current_user

router = APIRouter()

# Direct Messages


@router.get("/conversations", response_model=List[ConversationResponse])
def get_conversations(
    db: Session = Depends(get_db), current_user: User = Depends(get_current_user)
):
    """Get user's conversations"""
    conversations = (
        db.query(Conversation)
        .filter(
            or_(
                Conversation.participant_1_id == current_user.id,
                Conversation.participant_2_id == current_user.id,
            )
        )
        .order_by(Conversation.updated_at.desc())
        .all()
    )

    result = []
    for conv in conversations:
        # Determine other participant
        other_participant = (
            conv.participant_2
            if conv.participant_1_id == current_user.id
            else conv.participant_1
        )

        # Get last message
        last_message = (
            db.query(Message)
            .filter(Message.conversation_id == conv.id)
            .order_by(Message.created_at.desc())
            .first()
        )

        # Get unread count
        unread_count = (
            db.query(Message)
            .filter(
                Message.conversation_id == conv.id,
                Message.receiver_id == current_user.id,
                Message.is_read is False,
            )
            .count()
        )

        conv_response = ConversationResponse(
            id=conv.id,
            participant_1_id=conv.participant_1_id,
            participant_2_id=conv.participant_2_id,
            created_at=conv.created_at,
            updated_at=conv.updated_at,
            other_participant_name=f"{other_participant.first_name} {other_participant.last_name}",
            other_participant_id=other_participant.id,
            last_message=last_message.content if last_message else None,
            unread_count=unread_count,
        )
        result.append(conv_response)

    return result


@router.get("/conversations/{user_id}/messages", response_model=List[MessageResponse])
def get_conversation_messages(
    user_id: int,
    skip: int = 0,
    limit: int = 50,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """Get messages in a conversation with specific user"""

    # Check if users are connected
    connection = (
        db.query(Connection)
        .filter(
            or_(
                and_(
                    Connection.sender_id == current_user.id,
                    Connection.receiver_id == user_id,
                ),
                and_(
                    Connection.sender_id == user_id,
                    Connection.receiver_id == current_user.id,
                ),
            ),
            Connection.status == "accepted",
        )
        .first()
    )

    if not connection:
        raise HTTPException(status_code=403, detail="Can only message connections")

    # Get or create conversation
    conversation = (
        db.query(Conversation)
        .filter(
            or_(
                and_(
                    Conversation.participant_1_id == current_user.id,
                    Conversation.participant_2_id == user_id,
                ),
                and_(
                    Conversation.participant_1_id == user_id,
                    Conversation.participant_2_id == current_user.id,
                ),
            )
        )
        .first()
    )

    if not conversation:
        conversation = Conversation(
            participant_1_id=min(current_user.id, user_id),
            participant_2_id=max(current_user.id, user_id),
        )
        db.add(conversation)
        db.commit()
        db.refresh(conversation)

    # Get messages
    messages = (
        db.query(Message)
        .filter(Message.conversation_id == conversation.id)
        .order_by(Message.created_at.desc())
        .offset(skip)
        .limit(limit)
        .all()
    )

    # Mark messages as read
    db.query(Message).filter(
        Message.conversation_id == conversation.id,
        Message.receiver_id == current_user.id,
        Message.is_read is False,
    ).update({"is_read": True, "read_at": func.now()})
    db.commit()

    # Add sender names
    for message in messages:
        message.sender_name = f"{message.sender.first_name} {message.sender.last_name}"

    return messages


@router.post("/send", response_model=MessageResponse)
def send_message(
    message: MessageCreate,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """Send a direct message"""

    # Check if users are connected
    connection = (
        db.query(Connection)
        .filter(
            or_(
                and_(
                    Connection.sender_id == current_user.id,
                    Connection.receiver_id == message.receiver_id,
                ),
                and_(
                    Connection.sender_id == message.receiver_id,
                    Connection.receiver_id == current_user.id,
                ),
            ),
            Connection.status == "accepted",
        )
        .first()
    )

    if not connection:
        raise HTTPException(status_code=403, detail="Can only message connections")

    # Get or create conversation
    conversation = (
        db.query(Conversation)
        .filter(
            or_(
                and_(
                    Conversation.participant_1_id == current_user.id,
                    Conversation.participant_2_id == message.receiver_id,
                ),
                and_(
                    Conversation.participant_1_id == message.receiver_id,
                    Conversation.participant_2_id == current_user.id,
                ),
            )
        )
        .first()
    )

    if not conversation:
        conversation = Conversation(
            participant_1_id=min(current_user.id, message.receiver_id),
            participant_2_id=max(current_user.id, message.receiver_id),
        )
        db.add(conversation)
        db.commit()
        db.refresh(conversation)

    # Create message
    db_message = Message(
        conversation_id=conversation.id,
        sender_id=current_user.id,
        receiver_id=message.receiver_id,
        content=message.content,
        message_type=message.message_type,
        file_url=message.file_url,
    )

    db.add(db_message)

    # Update conversation timestamp
    conversation.updated_at = func.now()

    db.commit()
    db.refresh(db_message)

    db_message.sender_name = f"{current_user.first_name} {current_user.last_name}"
    return db_message


# Group Chats


@router.post("/groups", response_model=GroupChatResponse)
def create_group_chat(
    group_data: GroupChatCreate,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """Create a group chat"""

    # Create group chat
    group_chat = GroupChat(
        name=group_data.name,
        description=group_data.description,
        created_by=current_user.id,
    )

    db.add(group_chat)
    db.commit()
    db.refresh(group_chat)

    # Add creator as admin member
    creator_member = GroupChatMember(
        group_chat_id=group_chat.id, user_id=current_user.id, is_admin=True
    )
    db.add(creator_member)

    # Add other members
    for member_id in group_data.member_ids:
        if member_id != current_user.id:  # Don't add creator twice
            member = GroupChatMember(group_chat_id=group_chat.id, user_id=member_id)
            db.add(member)

    db.commit()

    group_chat.creator_name = f"{current_user.first_name} {current_user.last_name}"
    group_chat.member_count = len(group_data.member_ids) + 1  # Include creator

    return group_chat


@router.get("/groups", response_model=List[GroupChatResponse])
def get_my_group_chats(
    db: Session = Depends(get_db), current_user: User = Depends(get_current_user)
):
    """Get user's group chats"""

    # Get groups where user is a member
    memberships = (
        db.query(GroupChatMember)
        .filter(GroupChatMember.user_id == current_user.id)
        .all()
    )

    groups = []
    for membership in memberships:
        group = membership.group_chat
        if group.is_active:
            # Get member count
            member_count = (
                db.query(GroupChatMember)
                .filter(GroupChatMember.group_chat_id == group.id)
                .count()
            )

            # Get last message
            last_message = (
                db.query(GroupMessage)
                .filter(GroupMessage.group_chat_id == group.id)
                .order_by(GroupMessage.created_at.desc())
                .first()
            )

            group.creator_name = f"{group.creator.first_name} {group.creator.last_name}"
            group.member_count = member_count
            group.last_message = last_message.content if last_message else None

            groups.append(group)

    return groups


@router.get("/groups/{group_id}/messages", response_model=List[GroupMessageResponse])
def get_group_messages(
    group_id: int,
    skip: int = 0,
    limit: int = 50,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """Get group chat messages"""

    # Check if user is a member
    membership = (
        db.query(GroupChatMember)
        .filter(
            GroupChatMember.group_chat_id == group_id,
            GroupChatMember.user_id == current_user.id,
        )
        .first()
    )

    if not membership:
        raise HTTPException(status_code=403, detail="Not a member of this group")

    # Get messages
    messages = (
        db.query(GroupMessage)
        .filter(GroupMessage.group_chat_id == group_id)
        .order_by(GroupMessage.created_at.desc())
        .offset(skip)
        .limit(limit)
        .all()
    )

    # Add sender names
    for message in messages:
        message.sender_name = f"{message.sender.first_name} {message.sender.last_name}"

    return messages


@router.post("/groups/{group_id}/send", response_model=GroupMessageResponse)
def send_group_message(
    group_id: int,
    message: GroupMessageCreate,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """Send a group message"""

    # Check if user is a member
    membership = (
        db.query(GroupChatMember)
        .filter(
            GroupChatMember.group_chat_id == group_id,
            GroupChatMember.user_id == current_user.id,
        )
        .first()
    )

    if not membership:
        raise HTTPException(status_code=403, detail="Not a member of this group")

    # Create message
    db_message = GroupMessage(
        group_chat_id=group_id,
        sender_id=current_user.id,
        content=message.content,
        message_type=message.message_type,
        file_url=message.file_url,
    )

    db.add(db_message)
    db.commit()
    db.refresh(db_message)

    db_message.sender_name = f"{current_user.first_name} {current_user.last_name}"
    return db_message