"""Pydantic data models for invoice extraction and validation."""

from __future__ import annotations

from datetime import datetime
from enum import Enum
from typing import Any

from pydantic import BaseModel, Field, field_validator


class ValidationSeverity(str, Enum):
    ERROR = "error"
    WARNING = "warning"
    INFO = "info"


class LineItem(BaseModel):
    description: str = ""
    quantity: float | None = None
    unit_price: float | None = None
    total: float | None = None
    confidence: float = Field(default=0.0, ge=0.0, le=1.0)


class ValidationIssue(BaseModel):
    field: str
    severity: ValidationSeverity
    message: str
    rule_id: str


class ValidationReport(BaseModel):
    is_valid: bool
    score: float = Field(ge=0.0, le=1.0)
    issues: list[ValidationIssue] = Field(default_factory=list)

    def to_markdown(self) -> str:
        if not self.issues:
            return "✅ All business rules passed."
        lines = ["### Validation Report", ""]
        for issue in self.issues:
            icon = {"error": "❌", "warning": "⚠️", "info": "ℹ️"}[issue.severity.value]
            lines.append(f"- {icon} **{issue.field}** (`{issue.rule_id}`): {issue.message}")
        lines.append("")
        lines.append(f"**Overall score:** {self.score:.0%} | **Status:** {'PASS' if self.is_valid else 'REVIEW REQUIRED'}")
        return "\n".join(lines)


class ExtractedInvoice(BaseModel):
    vendor_name: str | None = None
    vendor_tax_id: str | None = None
    invoice_number: str | None = None
    invoice_date: str | None = None
    invoice_date_jalali: str | None = None
    buyer_name: str | None = None
    subtotal: float | None = None
    tax_amount: float | None = None
    total_amount: float | None = None
    currency: str = "IRR"
    line_items: list[LineItem] = Field(default_factory=list)
    raw_text: str = ""
    confidence: float = Field(default=0.0, ge=0.0, le=1.0)
    extraction_method: str = "hybrid_ocr_ner"
    processed_at: datetime = Field(default_factory=datetime.utcnow)

    @field_validator("currency", mode="before")
    @classmethod
    def normalize_currency(cls, value: Any) -> str:
        if not value:
            return "IRR"
        return str(value).upper()

    def to_export_dict(self) -> dict[str, Any]:
        return {
            "vendor": {
                "name": self.vendor_name,
                "tax_id": self.vendor_tax_id,
            },
            "invoice": {
                "number": self.invoice_number,
                "date_gregorian": self.invoice_date,
                "date_jalali": self.invoice_date_jalali,
                "buyer": self.buyer_name,
            },
            "amounts": {
                "subtotal": self.subtotal,
                "tax": self.tax_amount,
                "total": self.total_amount,
                "currency": self.currency,
            },
            "line_items": [item.model_dump() for item in self.line_items],
            "metadata": {
                "confidence": round(self.confidence, 3),
                "extraction_method": self.extraction_method,
                "processed_at": self.processed_at.isoformat() + "Z",
            },
        }