from __future__ import annotations

from datetime import datetime, timezone
from typing import Optional

from sqlmodel import Field, SQLModel


def _now() -> datetime:
    return datetime.now(timezone.utc)


#: Worst first. The order is load-bearing: findings are sorted and truncated by
#: it, so what survives a cap is always the part that matters.
SEVERITIES = ["critical", "high", "medium", "low", "unknown"]


class ImageScan(SQLModel, table=True):
    """The result of scanning one image tag for known vulnerabilities.

    One row per image reference, replaced on each scan. ``digest`` is the local
    image's digest when it was scanned: if the image is pulled again the digest
    moves and the result is stale, which the UI says rather than quietly
    presenting yesterday's counts for today's image.
    """

    id: Optional[int] = Field(default=None, primary_key=True)
    image: str = Field(index=True, unique=True)
    digest: Optional[str] = None
    scanner: str = "trivy"
    critical: int = 0
    high: int = 0
    medium: int = 0
    low: int = 0
    unknown: int = 0
    #: How many findings have a fixed version available. The actionable number —
    #: a hundred unfixable CVEs are noise, three fixable ones are a to-do.
    fixable: int = 0
    #: JSON list of the findings, worst first and capped (see scan_service).
    findings: str = "[]"
    scanned_at: datetime = Field(default_factory=_now)
    duration_ms: int = 0
    error: Optional[str] = None


# --- API schemas ---


class ScanRequest(SQLModel):
    image: str


class ScanSummary(SQLModel):
    image: str
    digest: Optional[str]
    scanner: str
    critical: int
    high: int
    medium: int
    low: int
    unknown: int
    fixable: int
    total: int
    scanned_at: datetime
    duration_ms: int
    error: Optional[str]
    #: True when the image has been pulled since this scan ran.
    stale: bool = False


class ScanDetail(ScanSummary):
    findings: list[dict] = []