use anyhow::Context;
use serde::{Deserialize, Serialize};
use std::collections::HashMap;

#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct ScrapeTarget {
    pub name: String,
    pub addr: String,
    #[serde(default = "default_metrics_path")]
    pub metrics_path: String,
    #[serde(default)]
    pub labels: HashMap<String, String>,
}

fn default_metrics_path() -> String {
    "/metrics".to_string()
}

impl ScrapeTarget {
    pub fn url(&self) -> String {
        if self.metrics_path.starts_with("http") {
            self.metrics_path.clone()
        } else {
            format!("http://{}{}", self.addr, self.metrics_path)
        }
    }
}

pub async fn load_targets_from_file(path: &str) -> anyhow::Result<Vec<ScrapeTarget>> {
    let content = tokio::fs::read_to_string(path)
        .await
        .context("read targets file")?;
    let targets: Vec<ScrapeTarget> =
        serde_json::from_str(&content).with_context(|| format!("parse targets file {path}"))?;
    Ok(targets)
}