//! Prometheus metrics inspection command (requires "metrics" feature)

use colored::Colorize;
use serde_json::json;

use crate::error::Result;

/// Execute metrics command.
///
/// # Errors
///
/// Returns an error if the metrics endpoint cannot be reached or output
/// serialization fails.
#[allow(clippy::unused_async)] // Reason: trait/interface requires async signature
pub async fn execute(
    format: crate::cli::OutputFormat,
    _metric: Option<String>,
    _help: bool,
) -> Result<()> {
    // In a real implementation, this would:
    // 1. Connect to Prometheus metrics endpoint
    // 2. Fetch metric values
    // 3. Display metrics with formatting
    // 4. Show metric types and help text

    let metrics = json!({
        "observer_events_processed_total": {
            "type": "counter",
            "value": 12850,
            "help": "Total number of events processed by observer system",
            "unit": "events"
        },
        "observer_events_matched_total": {
            "type": "counter",
            "value": 9124,
            "help": "Total number of events matched by at least one observer",
            "unit": "events"
        },
        "observer_actions_executed_total": {
            "type": "counter",
            "value": 15234,
            "help": "Total number of actions executed",
            "unit": "actions"
        },
        "observer_actions_failed_total": {
            "type": "counter",
            "value": 342,
            "help": "Total number of actions that failed",
            "unit": "actions"
        },
        "observer_action_duration_seconds": {
            "type": "histogram",
            "buckets": {
                "0.01": 4521,
                "0.05": 8234,
                "0.1": 2156,
                "0.5": 256,
                "1.0": 45,
                "inf": 22
            },
            "help": "Action execution duration in seconds",
            "unit": "seconds"
        },
        "observer_dlq_items_total": {
            "type": "gauge",
            "value": 28,
            "help": "Current number of items in dead letter queue",
            "unit": "items"
        },
        "observer_listener_health": {
            "type": "gauge",
            "value": 1.0,
            "help": "Listener health status (1=healthy, 0=unhealthy)",
            "unit": "status"
        }
    });

    match format {
        crate::cli::OutputFormat::Json => {
            let json_str =
                serde_json::to_string_pretty(&metrics).unwrap_or_else(|_| "{}".to_string());
            println!("{json_str}");
        },
        crate::cli::OutputFormat::Text => {
            println!("{}", "Observer Metrics".bold().underline());
            println!();

            for (metric_name, metric_data) in
                metrics.as_object().unwrap_or(&serde_json::Map::default())
            {
                let metric_type = metric_data["type"].as_str().unwrap_or("unknown");
                let help = metric_data["help"].as_str().unwrap_or("no help");

                println!("{}", metric_name.cyan().bold());
                println!("  {}: {}", "Type".yellow(), metric_type);
                println!("  {}: {}", "Help".yellow(), help);

                match metric_type {
                    "counter" | "gauge" => {
                        let value = metric_data["value"].as_u64().unwrap_or(0);
                        println!("  {}: {}", "Value".green(), value);
                    },
                    "histogram" => {
                        if let Some(buckets) = metric_data["buckets"].as_object() {
                            println!("  {}:", "Buckets".green());
                            for (bucket, count) in buckets {
                                println!("    {} s: {}", bucket.cyan(), count);
                            }
                        }
                    },
                    _ => {},
                }

                println!();
            }

            println!("{}", "Summary Statistics".bold().underline());
            println!(
                "{}: {}",
                "Total Events".cyan(),
                metrics["observer_events_processed_total"]["value"]
                    .as_u64()
                    .unwrap_or(0)
                    .to_string()
                    .green()
            );
            println!(
                "{}: {}",
                "Matched Events".cyan(),
                metrics["observer_events_matched_total"]["value"].as_u64().unwrap_or(0)
            );
            {
                #[allow(clippy::cast_precision_loss)]
                // Reason: f64 precision is acceptable for metrics display
                let match_rate =
                    metrics["observer_events_matched_total"]["value"].as_u64().unwrap_or(0) as f64
                        / metrics["observer_events_processed_total"]["value"].as_u64().unwrap_or(1)
                            as f64
                        * 100.0;
                println!("{}: {:.1}%", "Match Rate".cyan(), match_rate);
            }
            println!(
                "{}: {}",
                "Failed Actions".cyan(),
                metrics["observer_actions_failed_total"]["value"]
                    .as_u64()
                    .unwrap_or(0)
                    .to_string()
                    .red()
            );
            {
                #[allow(clippy::cast_precision_loss)]
                // Reason: f64 precision is acceptable for metrics display
                let failure_rate =
                    metrics["observer_actions_failed_total"]["value"].as_u64().unwrap_or(0) as f64
                        / metrics["observer_actions_executed_total"]["value"].as_u64().unwrap_or(1)
                            as f64
                        * 100.0;
                println!("{}: {:.1}%", "Failure Rate".cyan(), failure_rate);
            }
            println!(
                "{}: {}",
                "DLQ Items".cyan(),
                metrics["observer_dlq_items_total"]["value"].as_u64().unwrap_or(0)
            );
        },
    }

    Ok(())
}
