"""FHIR R4 resource generator for medication data."""

import json
import logging
from datetime import datetime
from typing import Any
from uuid import uuid4

from fhir.resources.medicationrequest import MedicationRequest
from fhir.resources.medicationstatement import MedicationStatement
from fhir.resources.codeableconcept import CodeableConcept
from fhir.resources.dosage import Dosage
from fhir.resources.reference import Reference

logger = logging.getLogger(__name__)


class FhirGenerator:
    """Generator for FHIR R4 medication resources."""

    def generate_medication_statement(
        self, medication_data: dict[str, Any]
    ) -> str:
        """
        Generate a FHIR MedicationStatement resource.

        Args:
            medication_data: Dictionary with medication info
                - drug_name: Name of the medication
                - dosage: Dosage amount and unit
                - frequency: How often to take
                - route: Route of administration (optional)
                - notes: Additional instructions (optional)

        Returns:
            JSON string of FHIR MedicationStatement
        """
        try:
            # Ensure drug_name is non-empty
            drug_name = medication_data.get("drug_name", "").strip()
            if not drug_name:
                drug_name = "Medication (see prescription)"

            # Build dosage text
            dosage_text = self._format_dosage_text(medication_data)
            if not dosage_text or dosage_text == "As directed":
                dosage_text = "See prescription for details"

            # Build dosage with optional route
            route_text = medication_data.get("route", "").strip()
            dosage_kwargs = {"text": dosage_text}
            if route_text:
                dosage_kwargs["route"] = CodeableConcept(text=route_text)

            statement = MedicationStatement(
                id=str(uuid4()),
                status="active",
                medicationCodeableConcept=CodeableConcept(text=drug_name),
                subject=Reference(reference="Patient/example"),
                effectiveDateTime=datetime.now().isoformat(),
                dosage=[Dosage(**dosage_kwargs)],
            )

            return statement.json(indent=2)

        except Exception as e:
            logger.error(f"Failed to generate MedicationStatement: {e}")
            raise ValueError("Could not generate FHIR MedicationStatement.")

    def generate_medication_request(
        self, medication_data: dict[str, Any]
    ) -> str:
        """
        Generate a FHIR MedicationRequest resource.

        Args:
            medication_data: Dictionary with medication info
                - drug_name: Name of the medication
                - dosage: Dosage amount and unit
                - frequency: How often to take
                - duration: How long to take
                - route: Route of administration (optional)
                - notes: Additional instructions (optional)

        Returns:
            JSON string of FHIR MedicationRequest
        """
        try:
            # Ensure drug_name is non-empty
            drug_name = medication_data.get("drug_name", "").strip()
            if not drug_name:
                drug_name = "Medication (see prescription)"

            # Build dosage text
            dosage_text = self._format_dosage_text(medication_data)
            if not dosage_text or dosage_text == "As directed":
                dosage_text = "See prescription for details"

            # Build dosage with optional route
            route_text = medication_data.get("route", "").strip()
            dosage_kwargs = {"text": dosage_text}
            if route_text:
                dosage_kwargs["route"] = CodeableConcept(text=route_text)

            request = MedicationRequest(
                id=str(uuid4()),
                status="active",
                intent="order",
                medicationCodeableConcept=CodeableConcept(text=drug_name),
                subject=Reference(reference="Patient/example"),
                authoredOn=datetime.now().isoformat(),
                dosageInstruction=[Dosage(**dosage_kwargs)],
            )

            return request.json(indent=2)

        except Exception as e:
            logger.error(f"Failed to generate MedicationRequest: {e}")
            raise ValueError("Could not generate FHIR MedicationRequest.")

    def _format_dosage_text(self, medication_data: dict[str, Any]) -> str:
        """Format dosage information as human-readable text."""
        parts = []

        if dosage := medication_data.get("dosage"):
            parts.append(dosage)

        if frequency := medication_data.get("frequency"):
            parts.append(frequency)

        if duration := medication_data.get("duration"):
            parts.append(f"for {duration}")

        if notes := medication_data.get("notes"):
            parts.append(f"({notes})")

        return " ".join(parts) if parts else "As directed"


def parse_medications_to_dict(extraction_text: str) -> list[dict[str, Any]]:
    """
    Parse extracted medication text into structured dictionaries.

    Args:
        extraction_text: Raw text from MedGemma extraction

    Returns:
        List of medication dictionaries
    """
    # Simple parsing - in production, would use more robust NLP
    medications = []

    lines = extraction_text.strip().split("\n")
    current_med = {}

    for line in lines:
        line = line.strip()
        if not line:
            if current_med:
                medications.append(current_med)
                current_med = {}
            continue

        line_lower = line.lower()

        if "drug" in line_lower or "medication" in line_lower or "name:" in line_lower:
            if current_med:
                medications.append(current_med)
            current_med = {"drug_name": line.split(":", 1)[-1].strip()}
        elif "dosage" in line_lower or "dose:" in line_lower:
            current_med["dosage"] = line.split(":", 1)[-1].strip()
        elif "frequency" in line_lower or "times" in line_lower:
            current_med["frequency"] = line.split(":", 1)[-1].strip()
        elif "duration" in line_lower or "days" in line_lower:
            current_med["duration"] = line.split(":", 1)[-1].strip()
        elif "route" in line_lower:
            current_med["route"] = line.split(":", 1)[-1].strip()
        elif "instruction" in line_lower or "note" in line_lower:
            current_med["notes"] = line.split(":", 1)[-1].strip()

    if current_med:
        medications.append(current_med)

    return medications if medications else [{"drug_name": "See prescription details", "notes": extraction_text}]