from __future__ import annotations

import re
from datetime import datetime
from typing import Annotated, Literal
from uuid import UUID

from pydantic import BaseModel, ConfigDict, Field, StringConstraints, model_validator

Checksum = Annotated[str, StringConstraints(pattern=r"^sha256:[0-9a-f]{64}$")]


class StrictModel(BaseModel):
    model_config = ConfigDict(extra="forbid", strict=True)


class Attachment(StrictModel):
    attachment_id: UUID
    quarantine_object_key: Annotated[str, StringConstraints(min_length=1, max_length=1024)]
    quarantine_version_id: Annotated[str, StringConstraints(min_length=1, max_length=512)]
    quarantine_etag: Annotated[str, StringConstraints(min_length=1, max_length=512)]
    mime_type: Annotated[str, StringConstraints(min_length=1, max_length=127)]
    size_bytes: int = Field(ge=1, le=5_242_880)
    checksum: Checksum

    @model_validator(mode="after")
    def canonical_key(self) -> Attachment:
        uuid = r"[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}"
        pattern = rf"^quarantine/users/{uuid}/dialogs/{uuid}/{uuid}$"
        if not self.quarantine_object_key.isascii() or not re.fullmatch(
            pattern, self.quarantine_object_key
        ):
            raise ValueError("quarantine_object_key is not canonical")
        return self


class TextCheck(StrictModel):
    message_id: UUID
    content_kind: Literal["text"]
    text: Annotated[str, StringConstraints(min_length=1, max_length=10_000)]
    attachment: None = None


class FileCheck(StrictModel):
    message_id: UUID
    content_kind: Literal["file"]
    text: Literal[""]
    attachment: Attachment


CheckRequest = Annotated[TextCheck | FileCheck, Field(discriminator="content_kind")]


class Verdict(StrictModel):
    verdict: Literal["allow", "deny"]
    processing_mode: Literal["standard", "mock"]
    config_version: int
    rule_id: str
    rules_version: str
    reason_code: Literal["message_blocked"] | None = None


class Pending(StrictModel):
    verdict: Literal["pending"] = "pending"
    processing_mode: Literal["standard"] = "standard"
    config_version: int
    task_id: UUID
    poll_after_ms: int = 2000
    expires_at: datetime
    rules_version: str


class ErrorBody(StrictModel):
    code: str
    message: str
    request_id: str
    details: dict[str, object] = Field(default_factory=dict)


class ErrorEnvelope(StrictModel):
    error: ErrorBody