from datetime import datetime
from typing import Literal

from pydantic import BaseModel, ConfigDict, Field


DocumentStatus = Literal["uploaded", "processing", "ready", "failed"]
EducationExtractionStatus = Literal[
    "uploaded",
    "classifying",
    "extracting",
    "ready",
    "needs_review",
    "extraction_failed",
]


class DocumentRead(BaseModel):
    id: str
    user_id: str
    title: str
    file_name: str
    file_type: str
    # file_path intentionally excluded — server filesystem path must not reach the client
    # extracted_text intentionally excluded — raw OCR text is private document content
    # extraction_error intentionally excluded — internal processing state must not leak
    subject: str | None
    chapter: str | None
    syllabus: str | None
    status: str
    chunk_count: int
    source_type: str = "pdf"
    material_type: str = "unknown"
    education_extraction_status: str = "uploaded"
    education_extraction_error: str | None = None
    education_warnings_json: list[str] = Field(default_factory=list)
    syllabus_items_count: int = 0
    pyq_questions_count: int = 0
    pyq_years_json: list[int] = Field(default_factory=list)
    extracted_text_length: int | None = None
    processing_started_at: datetime | None = None
    processing_completed_at: datetime | None = None
    created_at: datetime

    model_config = ConfigDict(from_attributes=True)


class DocumentUploadResponse(BaseModel):
    id: str
    user_id: str
    title: str
    file_name: str
    file_type: str
    # extracted_text intentionally excluded — raw OCR text is private document content
    subject: str | None
    chapter: str | None
    syllabus: str | None
    status: str
    chunk_count: int
    source_type: str = "pdf"
    material_type: str = "unknown"
    education_extraction_status: str = "uploaded"
    education_extraction_error: str | None = None
    education_warnings_json: list[str] = Field(default_factory=list)
    syllabus_items_count: int = 0
    pyq_questions_count: int = 0
    pyq_years_json: list[int] = Field(default_factory=list)
    extracted_text_length: int | None = None
    processing_started_at: datetime | None = None
    processing_completed_at: datetime | None = None
    created_at: datetime

    model_config = ConfigDict(from_attributes=True)


class DocumentPreview(BaseModel):
    id: str
    title: str
    file_name: str
    status: str
    extracted_text_preview: str
    extracted_text_length: int
    chunk_count: int