use std::{net::SocketAddr, str::FromStr};

use metrics::{Unit, counter, describe_counter, describe_gauge, gauge};

pub fn webhook_received(event_type: &str) {
    counter!("herald_webhooks_received_total", "event_type" => event_type.to_string()).increment(1);
}

pub fn webhook_duplicate(event_type: &str) {
    counter!("herald_webhooks_duplicate_total", "event_type" => event_type.to_string())
        .increment(1);
}

pub fn webhook_channel_full(event_type: &str) {
    counter!("herald_webhooks_channel_full_total", "event_type" => event_type.to_string())
        .increment(1);
}

pub fn increment_task_active() {
    gauge!("herald_bot_tasks_active").increment(1.0);
}

pub fn decrement_task_active() {
    gauge!("herald_bot_tasks_active").decrement(1.0);
}

pub fn task_completed(event_type: &str) {
    counter!("herald_bot_tasks_completed_total", "event_type" => event_type.to_string())
        .increment(1);
}

pub fn task_failed(event_type: &str) {
    counter!("herald_bot_tasks_failed_total", "event_type" => event_type.to_string()).increment(1);
}

pub fn openrouter_cost_usd(cost: f64) {
    counter!("herald_openrouter_cost_cents_total").increment((cost * 100.0).round() as u64);
}

pub fn describe() {
    describe_counter!(
        "herald_webhooks_received_total",
        Unit::Count,
        "Total webhooks received"
    );
    describe_counter!(
        "herald_webhooks_duplicate_total",
        Unit::Count,
        "Webhooks rejected as duplicates"
    );
    describe_counter!(
        "herald_webhooks_channel_full_total",
        Unit::Count,
        "Webhooks dropped because the bot channel was full"
    );
    describe_gauge!(
        "herald_bot_tasks_active",
        Unit::Count,
        "Bot tasks currently in progress"
    );
    describe_counter!(
        "herald_bot_tasks_completed_total",
        Unit::Count,
        "Bot tasks completed successfully"
    );
    describe_counter!(
        "herald_bot_tasks_failed_total",
        Unit::Count,
        "Bot tasks that failed"
    );
    describe_counter!(
        "herald_openrouter_cost_cents_total",
        Unit::Count,
        "Total OpenRouter cost in cents (divide by 100 for USD)"
    );
}

pub fn install(bind_addr: &str) -> anyhow::Result<()> {
    describe();

    let builder = metrics_exporter_prometheus::PrometheusBuilder::new();
    builder
        .with_http_listener(SocketAddr::from_str(bind_addr)?)
        .install()?;

    tracing::info!(bind_addr, "Prometheus metrics exporter installed");
    Ok(())
}