use axum::extract::{FromRef, Path, Query, State};
use axum::response::IntoResponse;
use axum::Json;
use serde::Deserialize;
use uuid::Uuid;

use crate::state::HealthState;

/// GET /fhir/R4/metadata — FHIR CapabilityStatement
pub async fn capability_statement<S>() -> Result<impl IntoResponse, erp_core::error::AppError>
where
    HealthState: FromRef<S>,
    S: Clone + Send + Sync + 'static,
{
    let stmt = serde_json::json!({
        "resourceType": "CapabilityStatement",
        "status": "active",
        "date": chrono::Utc::now().format("%Y-%m-%d").to_string(),
        "kind": "instance",
        "fhirVersion": "4.0.1",
        "format": ["application/fhir+json"],
        "rest": [{
            "mode": "server",
            "resource": [
                { "type": "Patient", "interaction": [{"code": "read"}, {"code": "search-type"}], "operation": [{"name": "everything"}] },
                { "type": "Observation", "interaction": [{"code": "read"}, {"code": "search-type"}], "operation": [{"name": "lastn"}] },
                { "type": "Device", "interaction": [{"code": "read"}, {"code": "search-type"}] },
                { "type": "DiagnosticReport", "interaction": [{"code": "read"}, {"code": "search-type"}] },
                { "type": "Encounter", "interaction": [{"code": "read"}, {"code": "search-type"}] },
                { "type": "Practitioner", "interaction": [{"code": "read"}, {"code": "search-type"}] },
                { "type": "Appointment", "interaction": [{"code": "read"}, {"code": "search-type"}] },
                { "type": "Task", "interaction": [{"code": "read"}, {"code": "search-type"}] },
            ],
            "operation": [
                { "name": "everything", "definition": "/fhir/R4/Patient/{id}/$everything" },
                { "name": "lastn", "definition": "/fhir/R4/Observation/$lastn" },
            ]
        }]
    });

    Ok(Json(stmt))
}

#[derive(Debug, Deserialize)]
pub struct SearchParams {
    pub patient: Option<String>,
    pub category: Option<String>,
    #[serde(rename = "_count")]
    pub count: Option<u32>,
    #[serde(rename = "_offset")]
    pub offset: Option<u32>,
}

// ── Patient ────────────────────────────────────────────────────────────

pub async fn search_patients(
    State(_state): State<HealthState>,
    Query(_params): Query<SearchParams>,
) -> Result<impl IntoResponse, erp_core::error::AppError> {
    Ok(Json(serde_json::json!({
        "resourceType": "Bundle", "type": "searchset", "total": 0, "entry": []
    })))
}

pub async fn get_patient(
    State(_state): State<HealthState>,
    Path(_id): Path<Uuid>,
) -> Result<impl IntoResponse, erp_core::error::AppError> {
    Ok(Json(serde_json::json!({
        "resourceType": "OperationOutcome",
        "issue": [{"severity": "information", "code": "not-found", "diagnostics": "Patient not implemented yet"}]
    })))
}

pub async fn patient_everything(
    State(_state): State<HealthState>,
    Path(_id): Path<Uuid>,
) -> Result<impl IntoResponse, erp_core::error::AppError> {
    Ok(Json(serde_json::json!({
        "resourceType": "Bundle", "type": "searchset", "total": 0, "entry": []
    })))
}

// ── Observation ────────────────────────────────────────────────────────

pub async fn search_observations(
    State(_state): State<HealthState>,
    Query(_params): Query<SearchParams>,
) -> Result<impl IntoResponse, erp_core::error::AppError> {
    Ok(Json(serde_json::json!({
        "resourceType": "Bundle", "type": "searchset", "total": 0, "entry": []
    })))
}

pub async fn observation_lastn(
    State(_state): State<HealthState>,
    Query(_params): Query<SearchParams>,
) -> Result<impl IntoResponse, erp_core::error::AppError> {
    Ok(Json(serde_json::json!({
        "resourceType": "Bundle", "type": "searchset", "total": 0, "entry": []
    })))
}

// ── Device ─────────────────────────────────────────────────────────────

pub async fn search_devices(
    State(_state): State<HealthState>,
    Query(_params): Query<SearchParams>,
) -> Result<impl IntoResponse, erp_core::error::AppError> {
    Ok(Json(serde_json::json!({
        "resourceType": "Bundle", "type": "searchset", "total": 0, "entry": []
    })))
}

pub async fn get_device(
    State(_state): State<HealthState>,
    Path(_id): Path<Uuid>,
) -> Result<impl IntoResponse, erp_core::error::AppError> {
    Ok(Json(serde_json::json!({
        "resourceType": "OperationOutcome",
        "issue": [{"severity": "information", "code": "not-found", "diagnostics": "Device not implemented yet"}]
    })))
}

// ── Practitioner ───────────────────────────────────────────────────────

pub async fn search_practitioners(
    State(_state): State<HealthState>,
    Query(_params): Query<SearchParams>,
) -> Result<impl IntoResponse, erp_core::error::AppError> {
    Ok(Json(serde_json::json!({
        "resourceType": "Bundle", "type": "searchset", "total": 0, "entry": []
    })))
}

pub async fn get_practitioner(
    State(_state): State<HealthState>,
    Path(_id): Path<Uuid>,
) -> Result<impl IntoResponse, erp_core::error::AppError> {
    Ok(Json(serde_json::json!({
        "resourceType": "OperationOutcome",
        "issue": [{"severity": "information", "code": "not-found", "diagnostics": "Practitioner not implemented yet"}]
    })))
}

// ── Appointment ────────────────────────────────────────────────────────

pub async fn search_appointments(
    State(_state): State<HealthState>,
    Query(_params): Query<SearchParams>,
) -> Result<impl IntoResponse, erp_core::error::AppError> {
    Ok(Json(serde_json::json!({
        "resourceType": "Bundle", "type": "searchset", "total": 0, "entry": []
    })))
}

pub async fn get_appointment(
    State(_state): State<HealthState>,
    Path(_id): Path<Uuid>,
) -> Result<impl IntoResponse, erp_core::error::AppError> {
    Ok(Json(serde_json::json!({
        "resourceType": "OperationOutcome",
        "issue": [{"severity": "information", "code": "not-found", "diagnostics": "Appointment not implemented yet"}]
    })))
}

// ── DiagnosticReport ───────────────────────────────────────────────────

pub async fn search_diagnostic_reports(
    State(_state): State<HealthState>,
    Query(_params): Query<SearchParams>,
) -> Result<impl IntoResponse, erp_core::error::AppError> {
    Ok(Json(serde_json::json!({
        "resourceType": "Bundle", "type": "searchset", "total": 0, "entry": []
    })))
}

pub async fn get_diagnostic_report(
    State(_state): State<HealthState>,
    Path(_id): Path<Uuid>,
) -> Result<impl IntoResponse, erp_core::error::AppError> {
    Ok(Json(serde_json::json!({
        "resourceType": "OperationOutcome",
        "issue": [{"severity": "information", "code": "not-found", "diagnostics": "DiagnosticReport not implemented yet"}]
    })))
}

// ── Encounter ──────────────────────────────────────────────────────────

pub async fn search_encounters(
    State(_state): State<HealthState>,
    Query(_params): Query<SearchParams>,
) -> Result<impl IntoResponse, erp_core::error::AppError> {
    Ok(Json(serde_json::json!({
        "resourceType": "Bundle", "type": "searchset", "total": 0, "entry": []
    })))
}

pub async fn get_encounter(
    State(_state): State<HealthState>,
    Path(_id): Path<Uuid>,
) -> Result<impl IntoResponse, erp_core::error::AppError> {
    Ok(Json(serde_json::json!({
        "resourceType": "OperationOutcome",
        "issue": [{"severity": "information", "code": "not-found", "diagnostics": "Encounter not implemented yet"}]
    })))
}

// ── Task ───────────────────────────────────────────────────────────────

pub async fn search_tasks(
    State(_state): State<HealthState>,
    Query(_params): Query<SearchParams>,
) -> Result<impl IntoResponse, erp_core::error::AppError> {
    Ok(Json(serde_json::json!({
        "resourceType": "Bundle", "type": "searchset", "total": 0, "entry": []
    })))
}

pub async fn get_task(
    State(_state): State<HealthState>,
    Path(_id): Path<Uuid>,
) -> Result<impl IntoResponse, erp_core::error::AppError> {
    Ok(Json(serde_json::json!({
        "resourceType": "OperationOutcome",
        "issue": [{"severity": "information", "code": "not-found", "diagnostics": "Task not implemented yet"}]
    })))
}