from uuid import UUID

from fastapi import APIRouter, Depends, HTTPException, status
from pydantic import BaseModel, Field
from sqlalchemy import select
from sqlalchemy.orm import Session, joinedload

from .auth import current_user
from .database import get_db
from .message_send_service import SendMessageError, send_template_messages
from .models import SenderConfig, TemplateConfig, UserAccount
from .sender_validators import (
    validate_dlt_entity_id,
    validate_purpose,
    validate_sender_id,
    validate_sender_type,
)
from .template_validators import (
    validate_dlt_template_id,
    validate_template_name,
    validate_template_text,
)

router = APIRouter(prefix="/api/v1/messaging", tags=["messaging"])


class CreateSenderRequest(BaseModel):
    sender_id: str = Field(min_length=3, max_length=11)
    sender_type: str
    purpose: str = Field(min_length=10, max_length=500)
    dlt_entity_id: str = Field(min_length=12, max_length=25)


class CreateTemplateRequest(BaseModel):
    sender_config_id: str
    template_name: str = Field(min_length=3, max_length=40)
    template_text: str = Field(min_length=10, max_length=1000)
    dlt_template_id: str = Field(min_length=12, max_length=25)


def serialize_sender(sender: SenderConfig) -> dict:
    return {
        "id": str(sender.id),
        "sender_id": sender.sender_id,
        "sender_type": sender.sender_type,
        "purpose": sender.purpose,
        "dlt_entity_id": sender.dlt_entity_id,
        "status": sender.status,
        "review_note": sender.review_note,
        "created_at": sender.created_at,
        "reviewed_at": sender.reviewed_at,
    }


def serialize_template(template: TemplateConfig) -> dict:
    return {
        "id": str(template.id),
        "sender_config_id": str(template.sender_config_id),
        "sender_id": template.sender_config.sender_id,
        "template_name": template.template_name,
        "template_text": template.template_text,
        "dlt_template_id": template.dlt_template_id,
        "status": template.status,
        "review_note": template.review_note,
        "created_at": template.created_at,
        "reviewed_at": template.reviewed_at,
    }


@router.get("/senders")
def list_senders(
    db: Session = Depends(get_db),
    user: UserAccount = Depends(current_user),
) -> list[dict]:
    senders = db.scalars(
        select(SenderConfig)
        .where(SenderConfig.user_id == user.id)
        .order_by(SenderConfig.created_at.desc())
    ).all()
    return [serialize_sender(sender) for sender in senders]


@router.post("/senders", status_code=status.HTTP_201_CREATED)
def create_sender(
    payload: CreateSenderRequest,
    db: Session = Depends(get_db),
    user: UserAccount = Depends(current_user),
) -> dict:
    try:
        sender_id = validate_sender_id(payload.sender_id)
        sender_type = validate_sender_type(payload.sender_type)
        purpose = validate_purpose(payload.purpose)
        dlt_entity_id = validate_dlt_entity_id(payload.dlt_entity_id)
    except ValueError as exc:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail=str(exc)) from exc

    existing = db.scalar(
        select(SenderConfig).where(
            SenderConfig.user_id == user.id,
            SenderConfig.sender_id == sender_id,
        )
    )
    if existing:
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="Sender ID already exists")

    sender = SenderConfig(
        user_id=user.id,
        sender_id=sender_id,
        sender_type=sender_type,
        purpose=purpose,
        dlt_entity_id=dlt_entity_id,
        status="pending",
    )
    db.add(sender)
    db.commit()
    db.refresh(sender)
    return serialize_sender(sender)


@router.get("/templates")
def list_templates(
    db: Session = Depends(get_db),
    user: UserAccount = Depends(current_user),
) -> list[dict]:
    templates = db.scalars(
        select(TemplateConfig)
        .options(joinedload(TemplateConfig.sender_config))
        .where(TemplateConfig.user_id == user.id)
        .order_by(TemplateConfig.created_at.desc())
    ).unique().all()
    return [serialize_template(template) for template in templates]


@router.post("/templates", status_code=status.HTTP_201_CREATED)
def create_template(
    payload: CreateTemplateRequest,
    db: Session = Depends(get_db),
    user: UserAccount = Depends(current_user),
) -> dict:
    try:
        template_name = validate_template_name(payload.template_name)
        template_text = validate_template_text(payload.template_text)
        dlt_template_id = validate_dlt_template_id(payload.dlt_template_id)
    except ValueError as exc:
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail=str(exc)) from exc

    sender = db.scalar(
        select(SenderConfig).where(
            SenderConfig.id == payload.sender_config_id,
            SenderConfig.user_id == user.id,
        )
    )
    if not sender:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Sender ID not found")
    if sender.status != "approved":
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
            detail="Template can only be linked to an approved sender ID",
        )

    existing = db.scalar(
        select(TemplateConfig).where(
            TemplateConfig.user_id == user.id,
            TemplateConfig.template_name == template_name,
        )
    )
    if existing:
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="Template name already exists")

    template = TemplateConfig(
        user_id=user.id,
        sender_config_id=sender.id,
        template_name=template_name,
        template_text=template_text,
        dlt_template_id=dlt_template_id,
        status="pending",
    )
    db.add(template)
    db.commit()
    db.refresh(template)
    db.refresh(sender)
    template.sender_config = sender
    return serialize_template(template)


class ComposeSendRequest(BaseModel):
    sender_config_id: UUID
    template_id: UUID
    numbers: str = Field(min_length=10, max_length=5000)
    message: str = Field(min_length=1, max_length=1000)
    campaign_name: str | None = Field(default=None, max_length=120)


@router.post("/send")
def compose_send_message(
    payload: ComposeSendRequest,
    db: Session = Depends(get_db),
    user: UserAccount = Depends(current_user),
) -> dict:
    try:
        return send_template_messages(
            db,
            user,
            sender_config_id=payload.sender_config_id,
            template_id=payload.template_id,
            message=payload.message,
            recipients=[part.strip() for part in payload.numbers.split(",") if part.strip()],
            campaign_name=payload.campaign_name,
        )
    except SendMessageError as exc:
        raise HTTPException(status_code=exc.status_code, detail=exc.detail) from exc