"""
Pydantic models for request/response validation across the Puff n Parse API.
"""
from pydantic import BaseModel, Field
from typing import Literal, Optional
from enum import Enum


class FileType(str, Enum):
    """Supported input file types."""
    PDF = "pdf"
    JPEG = "jpeg"
    PNG = "png"
    URL = "url"


class ProcessingLane(str, Enum):
    """Which engine processes the file."""
    PDF_PARSER = "pdf_parser"
    OCR_ENGINE = "ocr_engine"
    URL_PARSER = "url_parser"

class DocumentType(str, Enum):
    """How the document data is structured."""
    FORM = "form"
    FREE_TEXT = "free_text"


class ExportFormat(str, Enum):
    """Supported output file formats."""
    CSV = "csv"
    XLSX = "xlsx"
    DOCX = "docx"
    PDF = "pdf"


class ExtractedField(BaseModel):
    """A single extracted field with its name, value, and metadata."""
    name: str = Field(..., description="The field label/name extracted from the document")
    value: str = Field(..., description="The field value extracted from the document")
    field_type: str = Field(default="text", description="Type of field: text, number, date, etc.")
    confidence: float = Field(default=0.0, ge=0.0, le=1.0, description="OCR confidence score 0-1")
    editable: bool = Field(default=True, description="Whether the user can edit this value")


class ExtractionMetadata(BaseModel):
    """Metadata about the extraction process."""
    filename: str
    file_type: FileType
    processing_lane: ProcessingLane
    document_type: DocumentType = DocumentType.FORM
    page_count: int = 1
    language_detected: Optional[str] = None
    processing_time_ms: int = 0
    confidence_score: float = 0.0


class ExtractionResponse(BaseModel):
    """Response returned after file upload and extraction."""
    success: bool = True
    fields: list[ExtractedField] = []
    metadata: ExtractionMetadata
    summary: Optional[str] = None
    message: str = "Extraction completed successfully"


class ExportRequest(BaseModel):
    """Request body for file export."""
    fields: list[ExtractedField]
    format: ExportFormat
    filename: Optional[str] = "export"


class TierStatus(BaseModel):
    """Current usage status for the user's tier."""
    is_registered: bool = False
    sessions_used: int = 0
    sessions_limit: int = 5
    files_this_session: int = 0
    files_limit: int = 3
    max_file_size_mb: int = 10


class TierCheckResponse(BaseModel):
    """Response from tier validation."""
    allowed: bool
    tier: TierStatus
    message: str = ""


class ErrorResponse(BaseModel):
    """Standard error response."""
    success: bool = False
    error: str
    code: str = "UNKNOWN_ERROR"