first commit

src/home_assistant.rs

@@ -0,0 +1,40 @@
+use anyhow::{anyhow, bail, Context, Result};
+use serde_json::Value;
+use url::Url;
+use crate::models::HomeAssistantSettings;
+
+pub async fn read_temperature(
+    client: &reqwest::Client,
+    settings: &HomeAssistantSettings,
+    entity_override: Option<&str>,
+) -> Result<f64> {
+    if settings.url.trim().is_empty() { bail!("Home Assistant URL is not configured") }
+    if settings.token.trim().is_empty() { bail!("Home Assistant token is not configured") }
+    let entity = entity_override.filter(|v| !v.trim().is_empty())
+        .unwrap_or(settings.default_entity_id.trim());
+    if entity.is_empty() { bail!("Home Assistant entity_id is not configured") }
+
+    let mut base = Url::parse(settings.url.trim()).context("invalid Home Assistant URL")?;
+    if !matches!(base.scheme(), "http" | "https") { bail!("Home Assistant URL must use http or https") }
+    let path = format!("api/states/{}", entity.trim_start_matches('/'));
+    base = base.join(&path).context("cannot build Home Assistant API URL")?;
+
+    let response = client.get(base)
+        .bearer_auth(settings.token.trim())
+        .header("Accept", "application/json")
+        .send().await.context("Home Assistant request failed")?;
+    if !response.status().is_success() {
+        let status = response.status();
+        let body = response.text().await.unwrap_or_default();
+        bail!("Home Assistant returned {status}: {}", body.chars().take(200).collect::<String>())
+    }
+    let payload: Value = response.json().await.context("invalid Home Assistant JSON")?;
+    let state = payload.get("state").and_then(Value::as_str)
+        .ok_or_else(|| anyhow!("Home Assistant state is missing"))?;
+    let mut temperature: f64 = state.parse().context("Home Assistant state is not a number")?;
+    let unit = payload.pointer("/attributes/unit_of_measurement").and_then(Value::as_str).unwrap_or("°C");
+    if unit.eq_ignore_ascii_case("°F") || unit.eq_ignore_ascii_case("F") {
+        temperature = (temperature - 32.0) * 5.0 / 9.0;
+    }
+    Ok((temperature * 10.0).round() / 10.0)
+}