use std::{sync::Arc, time::Duration};

use anyhow::Context;
use nvml_wrapper::{enum_wrappers::device::TemperatureSensor, Nvml};
use sqlx::PgPool;
use tokio::time::sleep;

use crate::config::Settings;

pub async fn spawn_telemetry_task(pool: PgPool, settings: Arc<Settings>) -> anyhow::Result<()> {
    if !settings.gpu_nvml_enabled {
        return Ok(());
    }

    let nvml = match Nvml::init() {
        Ok(nvml) => Arc::new(nvml),
        Err(error) => {
            tracing::warn!("NVML nav pieejams: {}", error);
            return Ok(());
        }
    };

    tokio::spawn(async move {
        loop {
            if let Err(error) = collect_once(&pool, &nvml).await {
                tracing::warn!("GPU telemetry kļūda: {}", error);
            }
            sleep(Duration::from_millis(settings.gpu_telemetry_poll_ms.max(500))).await;
        }
    });
    Ok(())
}

async fn collect_once(pool: &PgPool, nvml: &Nvml) -> anyhow::Result<()> {
    let count = nvml.device_count().context("Neizdevās nolasīt NVML device count")?;
    for device_index in 0..count {
        let device = nvml
            .device_by_index(device_index)
            .with_context(|| format!("Neizdevās nolasīt GPU {}", device_index))?;
        let memory = device.memory_info().context("Neizdevās nolasīt GPU memory")?;
        let utilization = device.utilization_rates().ok();
        let power = device.power_usage().ok().map(|value| value as f64 / 1000.0);
        let temperature = device.temperature(TemperatureSensor::Gpu).ok().map(|value| value as i32);
        let name = device.name().unwrap_or_else(|_| format!("GPU-{}", device_index));
        let used_mb = (memory.used / 1024 / 1024) as i32;
        let total_mb = (memory.total / 1024 / 1024) as i32;
        let free_mb = (memory.free / 1024 / 1024) as i32;
        let utilization_percent = utilization.map(|item| item.gpu as f32).unwrap_or(0.0);
        sqlx::query(
            r#"
            INSERT INTO vision_gpu_resources (
                device_id, device_name, memory_total_mb, memory_available_mb, active_jobs,
                utilization_percent, status, metadata_json, last_heartbeat
            )
            VALUES ($1, $2, $3, $4, COALESCE((SELECT active_jobs FROM vision_gpu_resources WHERE device_id = $1), 0),
                    $5, 'healthy', $6, NOW())
            ON CONFLICT (device_id) DO UPDATE SET
                device_name = EXCLUDED.device_name,
                memory_total_mb = EXCLUDED.memory_total_mb,
                memory_available_mb = EXCLUDED.memory_available_mb,
                utilization_percent = EXCLUDED.utilization_percent,
                metadata_json = EXCLUDED.metadata_json,
                status = 'healthy',
                last_heartbeat = NOW()
            "#,
        )
        .bind(device_index as i32)
        .bind(name)
        .bind(total_mb)
        .bind(free_mb)
        .bind(utilization_percent)
        .bind(serde_json::json!({
            "temperature_c": temperature,
            "power_watts": power,
            "memory_used_mb": used_mb,
        }))
        .execute(pool)
        .await
        .context("Neizdevās atjaunināt GPU telemetry")?;

        sqlx::query(
            r#"
            INSERT INTO vision_gpu_telemetry_history (
                device_id, temperature_c, power_watts, memory_used_mb, memory_total_mb, utilization_percent, metadata_json
            )
            VALUES ($1, $2, $3, $4, $5, $6, $7)
            "#,
        )
        .bind(device_index as i32)
        .bind(temperature)
        .bind(power)
        .bind(used_mb)
        .bind(total_mb)
        .bind(utilization_percent)
        .bind(serde_json::json!({
            "memory_available_mb": free_mb,
        }))
        .execute(pool)
        .await
        .context("Neizdevās saglabāt GPU telemetry history")?;
    }
    Ok(())
}