Energy Analyzer

use lager::LagerBox;

let lager = LagerBox::from_env()?;
let energy = lager.energy_analyzer("energy1");

pub struct EnergyReading {
    pub energy_j: Option<f64>,    // joules
    pub charge_c: Option<f64>,    // coulombs
    pub duration_s: Option<f64>,  // the window actually used
}

pub struct EnergyStats {
    pub current: Option<StatSummary>,  // amps
    pub voltage: Option<StatSummary>,  // volts
    pub power: Option<StatSummary>,    // watts
}

pub struct StatSummary {
    pub mean: Option<f64>,
    pub min: Option<f64>,
    pub max: Option<f64>,
    pub std: Option<f64>,
}

let r = energy.read_energy(10.0)?;
println!("{:?} J, {:?} C", r.energy_j, r.charge_c);

let s = energy.read_stats(5.0)?;
if let Some(c) = s.current {
    println!("mean {:?} A, peak {:?} A", c.mean, c.max);
}

let energy = lager.energy_analyzer("energy1");

// One full wake/transmit/sleep cycle.
let cycle = energy.read_energy(30.0)?;
let joules = cycle.energy_j.expect("analyzer reports energy");

// 2000 mAh at 3.7 V, in joules.
let battery_j = 2.0 * 3.7 * 3600.0;
let days = (battery_j / joules) * 30.0 / 86_400.0;
println!("projected battery life: {days:.1} days");
assert!(days > 180.0, "only {days:.1} days of battery life");

let s = energy.read_stats(10.0)?;
let c = s.current.expect("analyzer reports current");
let (mean, peak) = (c.mean.unwrap_or(0.0), c.max.unwrap_or(0.0));
assert!(peak < mean * 20.0, "peak {peak:.4} A is {:.0}x the mean", peak / mean);