import logging
import uuid
from collections.abc import Mapping
from datetime import datetime, timedelta
from typing import Optional

from sqlalchemy import text

from app.dao import BaseDAO

logger = logging.getLogger("app.dao.binding")


class BindingDAO(BaseDAO):
    def start_bind(self, user_id: int, device_id: str, child_id: int) -> str:
        bind_token = str(uuid.uuid4())
        expires_at = datetime.utcnow() + timedelta(minutes=10)

        self.db.execute(
            text(
                """
                INSERT INTO device_bind_sessions (bind_token, device_id, initiator_user_id, target_child_id, expires_at, status)
                VALUES (:bind_token, :device_id, :initiator_user_id, :target_child_id, :expires_at, 1)
                """
            ),
            {
                "bind_token": bind_token,
                "device_id": device_id,
                "initiator_user_id": user_id,
                "target_child_id": child_id,
                "expires_at": expires_at,
            },
        )
        self.commit()
        return bind_token

    def get_session(self, bind_token: str, user_id: int) -> Optional[Mapping]:
        return (
            self.db.execute(
                text(
                    "SELECT * FROM device_bind_sessions WHERE bind_token = :bind_token AND initiator_user_id = :user_id"
                ),
                {"bind_token": bind_token, "user_id": user_id},
            )
            .mappings()
            .first()
        )

    def confirm_bind(self, session_id: int, device_id: str, child_id: int, user_id: int) -> None:
        self.db.execute(
            text("UPDATE device_bind_sessions SET status = 2, confirmed_at = CURRENT_TIMESTAMP WHERE id = :id"),
            {"id": session_id},
        )

        existing = self.db.execute(
            text("SELECT id FROM device_bindings WHERE device_id = :device_id OR child_id = :child_id"),
            {"device_id": device_id, "child_id": child_id},
        ).scalar_one_or_none()

        if existing:
            self.db.execute(
                text(
                    "UPDATE device_bindings SET child_id = :child_id, status = 1, unbound_at = NULL WHERE device_id = :device_id"
                ),
                {"device_id": device_id, "child_id": child_id},
            )
        else:
            self.db.execute(
                text(
                    "INSERT INTO device_bindings (device_id, child_id, status, bound_at) VALUES (:device_id, :child_id, 1, CURRENT_TIMESTAMP)"
                ),
                {"device_id": device_id, "child_id": child_id},
            )

        self.db.execute(
            text(
                "INSERT INTO device_bind_history (device_id, child_id, bound_by_user_id, bind_source, bound_at) VALUES (:device_id, :child_id, :user_id, 1, CURRENT_TIMESTAMP)"
            ),
            {"device_id": device_id, "child_id": child_id, "user_id": user_id},
        )
        self.commit()

    def direct_bind(self, device_id: str, child_id: int, user_id: int) -> None:
        # Check if binding exists for this device_id
        existing_by_device = (
            self.db.execute(
                text("SELECT id FROM device_bindings WHERE device_id = :device_id"),
                {"device_id": device_id},
            ).fetchone()
        )

        # Check if this child is already bound to a different device
        existing_by_child = (
            self.db.execute(
                text("SELECT id FROM device_bindings WHERE child_id = :child_id AND status = 1"),
                {"child_id": child_id},
            ).fetchone()
        )

        if existing_by_device:
            # Update existing binding for this device
            self.db.execute(
                text(
                    "UPDATE device_bindings SET child_id = :child_id, status = 1, unbound_at = NULL WHERE device_id = :device_id"
                ),
                {"device_id": device_id, "child_id": child_id},
            )
            self.db.execute(
                text(
                    "INSERT INTO device_bind_history (device_id, child_id, bound_by_user_id, bind_source, bound_at) VALUES (:device_id, :child_id, :user_id, 2, CURRENT_TIMESTAMP)"
                ),
                {"device_id": device_id, "child_id": child_id, "user_id": user_id},
            )
            self.commit()
            return
        elif existing_by_child:
            # Child already bound to another device - update that binding
            self.db.execute(
                text(
                    "UPDATE device_bindings SET device_id = :device_id, status = 1, unbound_at = NULL WHERE child_id = :child_id AND status = 1"
                ),
                {"device_id": device_id, "child_id": child_id},
            )
            # Skip INSERT since we updated
            self.db.execute(
                text(
                    "INSERT INTO device_bind_history (device_id, child_id, bound_by_user_id, bind_source, bound_at) VALUES (:device_id, :child_id, :user_id, 2, CURRENT_TIMESTAMP)"
                ),
                {"device_id": device_id, "child_id": child_id, "user_id": user_id},
            )
            self.commit()
            return
        else:
            # Insert new binding
            self.db.execute(
                text(
                    "INSERT INTO device_bindings (device_id, child_id, status, bound_at) VALUES (:device_id, :child_id, 1, CURRENT_TIMESTAMP)"
                ),
                {"device_id": device_id, "child_id": child_id},
            )

        # Add history
        self.db.execute(
            text(
                "INSERT INTO device_bind_history (device_id, child_id, bound_by_user_id, bind_source, bound_at) VALUES (:device_id, :child_id, :user_id, 2, CURRENT_TIMESTAMP)"
            ),
            {"device_id": device_id, "child_id": child_id, "user_id": user_id},
        )
        self.commit()

    def get_current_by_user(self, user_id: int) -> Optional[Mapping]:
        return (
            self.db.execute(
                text(
                    """
                    SELECT b.* FROM device_bindings b
                    JOIN children c ON b.child_id = c.child_id
                    WHERE c.parent_user_id = :user_id AND b.status = 1
                    ORDER BY b.bound_at DESC
                    LIMIT 1
                    """
                ),
                {"user_id": user_id},
            )
            .mappings()
            .first()
        )

    def get_by_device(self, device_id: str, user_id: int) -> Optional[Mapping]:
        return (
            self.db.execute(
                text(
                    """
                    SELECT b.* FROM device_bindings b
                    JOIN children c ON b.child_id = c.child_id
                    WHERE b.device_id = :device_id AND c.parent_user_id = :user_id AND b.status = 1
                    """
                ),
                {"device_id": device_id, "user_id": user_id},
            )
            .mappings()
            .first()
        )

    def unbind(self, device_id: str, user_id: int) -> bool:
        row = self.get_by_device(device_id, user_id)
        if not row:
            return False

        self.db.execute(
            text("UPDATE device_bindings SET status = 0, unbound_at = CURRENT_TIMESTAMP WHERE id = :id"),
            {"id": row["id"]},
        )

        self.db.execute(
            text(
                "INSERT INTO device_bind_history (device_id, child_id, bound_by_user_id, unbound_by_user_id, bind_source, bound_at, unbound_at, unbind_reason) SELECT device_id, child_id, bound_by_user_id, :user_id, bind_source, bound_at, CURRENT_TIMESTAMP, 'user_unbind' FROM device_bind_history WHERE device_id = :device_id AND unbound_at IS NULL"
            ),
            {"device_id": device_id, "user_id": user_id},
        )
        self.commit()
        return True

    def list_history(self, device_id: str, limit: int = 20, cursor: datetime = None) -> list[Mapping]:
        params = {"device_id": device_id, "limit": limit + 1}
        where = "device_id = :device_id"
        if cursor:
            where += " AND bound_at < :cursor"
            params["cursor"] = cursor

        rows = (
            self.db.execute(
                text(
                    f"""
                    SELECT * FROM device_bind_history
                    WHERE {where}
                    ORDER BY bound_at DESC
                    LIMIT :limit
                    """
                ),
                params,
            )
            .mappings()
            .all()
        )
        return rows