from datetime import datetime, timedelta, timezone
from math import ceil

from fastapi import APIRouter, Depends, HTTPException, Query, status
from sqlalchemy import func, select
from sqlalchemy.orm import Session, joinedload

from .auth import current_user
from .database import get_db
from .models import OtpMessageLog, SmsMessageLog, UserAccount, VoiceCall, VoiceSocketEndpoint

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

LOG_TYPES = frozenset({"outbound", "inbound", "sms", "otp"})
DEFAULT_RANGE_DAYS = 7
MAX_RANGE_DAYS = 31
PAGE_SIZE = 10


def _parse_time(value: str | None, *, fallback: datetime) -> datetime:
    if not value:
        return fallback
    normalized = value.strip()
    if normalized.endswith("Z"):
        normalized = normalized[:-1] + "+00:00"
    try:
        parsed = datetime.fromisoformat(normalized)
    except ValueError as exc:
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
            detail="Invalid datetime format. Use ISO 8601.",
        ) from exc
    if parsed.tzinfo is None:
        parsed = parsed.replace(tzinfo=timezone.utc)
    return parsed.astimezone(timezone.utc)


def _resolve_time_window(from_value: str | None, to_value: str | None) -> tuple[datetime, datetime]:
    now = datetime.now(timezone.utc)
    end = _parse_time(to_value, fallback=now)
    start = _parse_time(from_value, fallback=end - timedelta(days=DEFAULT_RANGE_DAYS))

    if start > end:
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
            detail="'from' must be earlier than 'to'.",
        )

    if (end - start).days > MAX_RANGE_DAYS:
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
            detail=f"Time range cannot exceed {MAX_RANGE_DAYS} days.",
        )
    return start, end


def _serialize_voice_call(call: VoiceCall, *, socket_name: str | None) -> dict:
    if call.direction == "inbound":
        from_number = call.to_number
        to_number = call.from_did
    else:
        from_number = call.from_did
        to_number = call.to_number

    payload = {
        "id": str(call.id),
        "from": from_number,
        "to": to_number,
        "status": call.status,
        "time": call.created_at,
    }
    if call.direction == "outbound":
        payload["socket_name"] = socket_name or "—"
    return payload


def _serialize_sms_log(entry: SmsMessageLog) -> dict:
    return {
        "id": str(entry.id),
        "from": entry.sender_id,
        "to": entry.to_number,
        "template": entry.template_name,
        "status": entry.status,
        "time": entry.created_at,
    }


def _serialize_otp_log(entry: OtpMessageLog) -> dict:
    return {
        "id": str(entry.id),
        "to": entry.to_number,
        "otp_type": entry.template_type,
        "project": entry.project_name,
        "status": entry.status,
        "time": entry.created_at,
    }


@router.get("")
def list_logs(
    log_type: str = Query(..., alias="type"),
    from_value: str | None = Query(default=None, alias="from"),
    to_value: str | None = Query(default=None, alias="to"),
    page: int = Query(default=1, ge=1),
    db: Session = Depends(get_db),
    user: UserAccount = Depends(current_user),
) -> dict:
    normalized_type = log_type.strip().lower()
    if normalized_type not in LOG_TYPES:
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
            detail=f"type must be one of: {', '.join(sorted(LOG_TYPES))}",
        )

    start, end = _resolve_time_window(from_value, to_value)
    offset = (page - 1) * PAGE_SIZE

    if normalized_type in {"outbound", "inbound"}:
        direction = normalized_type
        filters = [
            VoiceCall.user_id == user.id,
            VoiceCall.direction == direction,
            VoiceCall.created_at >= start,
            VoiceCall.created_at <= end,
        ]
        total = db.scalar(select(func.count()).select_from(VoiceCall).where(*filters)) or 0
        calls = db.scalars(
            select(VoiceCall)
            .options(joinedload(VoiceCall.phone_number))
            .where(*filters)
            .order_by(VoiceCall.created_at.desc())
            .offset(offset)
            .limit(PAGE_SIZE)
        ).unique().all()

        socket_by_phone: dict = {}
        if direction == "outbound" and calls:
            phone_ids = [call.phone_number_id for call in calls]
            sockets = db.scalars(
                select(VoiceSocketEndpoint).where(
                    VoiceSocketEndpoint.user_id == user.id,
                    VoiceSocketEndpoint.phone_number_id.in_(phone_ids),
                )
            ).all()
            socket_by_phone = {socket.phone_number_id: socket.name for socket in sockets}

        items = [
            _serialize_voice_call(call, socket_name=socket_by_phone.get(call.phone_number_id))
            for call in calls
        ]
    elif normalized_type == "sms":
        filters = [
            SmsMessageLog.user_id == user.id,
            SmsMessageLog.created_at >= start,
            SmsMessageLog.created_at <= end,
        ]
        total = db.scalar(select(func.count()).select_from(SmsMessageLog).where(*filters)) or 0
        entries = db.scalars(
            select(SmsMessageLog)
            .where(*filters)
            .order_by(SmsMessageLog.created_at.desc())
            .offset(offset)
            .limit(PAGE_SIZE)
        ).all()
        items = [_serialize_sms_log(entry) for entry in entries]
    else:
        filters = [
            OtpMessageLog.user_id == user.id,
            OtpMessageLog.created_at >= start,
            OtpMessageLog.created_at <= end,
        ]
        total = db.scalar(select(func.count()).select_from(OtpMessageLog).where(*filters)) or 0
        entries = db.scalars(
            select(OtpMessageLog)
            .where(*filters)
            .order_by(OtpMessageLog.created_at.desc())
            .offset(offset)
            .limit(PAGE_SIZE)
        ).all()
        items = [_serialize_otp_log(entry) for entry in entries]

    total_pages = ceil(total / PAGE_SIZE) if total else 0
    return {
        "type": normalized_type,
        "page": page,
        "page_size": PAGE_SIZE,
        "total": total,
        "total_pages": total_pages,
        "from": start,
        "to": end,
        "items": items,
    }