//! Drug Interaction Handlers (Phase 2.8)

use axum::{
    extract::{Extension, State},
    http::StatusCode,
    Json,
};
use serde::{Deserialize, Serialize};

use crate::{
    auth::jwt::Claims,
    config::AppState,
    services::openfda_service::{DrugInteraction, InteractionSeverity},
};

#[derive(Debug, Deserialize)]
pub struct CheckInteractionRequest {
    pub medications: Vec<String>,
}

#[derive(Debug, Serialize)]
pub struct InteractionResponse {
    pub interactions: Vec<DrugInteraction>,
    pub has_severe: bool,
    pub disclaimer: String,
}

/// Check interactions between medications
pub async fn check_interactions(
    _claims: Extension<Claims>,
    State(state): State<AppState>,
    Json(request): Json<CheckInteractionRequest>,
) -> Result<Json<InteractionResponse>, StatusCode> {
    if request.medications.len() < 2 {
        return Err(StatusCode::BAD_REQUEST);
    }

    let interaction_service = state
        .interaction_service
        .as_ref()
        .ok_or(StatusCode::SERVICE_UNAVAILABLE)?;

    match interaction_service
        .check_eu_medications(&request.medications)
        .await
    {
        Ok(interactions) => {
            let has_severe = interactions
                .iter()
                .any(|i| matches!(i.severity, InteractionSeverity::Severe));

            Ok(Json(InteractionResponse {
                interactions,
                has_severe,
                disclaimer: "This information is advisory only. Consult with a physician for detailed information about drug interactions.".to_string(),
            }))
        }
        Err(_) => Err(StatusCode::INTERNAL_SERVER_ERROR),
    }
}

#[derive(Debug, Deserialize)]
pub struct CheckNewMedicationRequest {
    pub new_medication: String,
    pub existing_medications: Vec<String>,
}

#[derive(Debug, Serialize)]
pub struct NewMedicationCheckResult {
    pub interactions: Vec<DrugInteraction>,
    pub has_severe: bool,
    pub disclaimer: String,
}

/// Check if a new medication has interactions with existing medications
pub async fn check_new_medication(
    _claims: Extension<Claims>,
    State(state): State<AppState>,
    Json(request): Json<CheckNewMedicationRequest>,
) -> Result<Json<InteractionResponse>, StatusCode> {
    let interaction_service = state
        .interaction_service
        .as_ref()
        .ok_or(StatusCode::SERVICE_UNAVAILABLE)?;

    match interaction_service
        .check_new_medication(&request.new_medication, &request.existing_medications)
        .await
    {
        Ok(result) => Ok(Json(InteractionResponse {
            interactions: result.interactions,
            has_severe: result.has_severe,
            disclaimer: result.disclaimer,
        })),
        Err(_) => Err(StatusCode::INTERNAL_SERVER_ERROR),
    }
}