//! Native headless runner for the simulation.
//!
//!   cargo run --release --example sim_run -- [options]
//!
//! Options (all optional; a preset gives the defaults, the others override it):
//!   --scenario NAME     big-smart | logistics | ew-adaptive            (default big-smart)
//!   --seed N            random seed
//!   --layout FILE       systems from a text file, replacing the preset's; one per line:
//!                         `KIND X Z [HEADING_RAD] [empty]`   (`#` starts a comment)
//!                       KIND is a system key (patriot, tor, radar, depot, tzm, ew, ...)
//!   --raid SPEC         replaces the preset's raids; repeatable. SPEC is
//!                         `kind=count,kind=count[;dist=500][;aim=smart|objects|sams][;approach=sector|two|all|waves][;at=TICK]`
//!   --terrain T         flat[:HEIGHT] | hills[:BASE:AMP:PERIOD]
//!   --ticks N           tick limit (20 a second)
//!   --run-on            do not stop when the raids have ended
//!   --ew / --no-ew      EW stations on or off
//!   --json              one JSON object instead of text
//!   --list              list scenarios, system and drone kinds
//! Exit code 1 when the run has problems (NaN positions, stuck trucks, a raid that never ended).
//! Native timings are for comparing runs on one machine, not an estimate of WASM/GPU cost.
mod harness;
use airdef::sim::{Aim, Approach, DroneKind, SamKind};
use glam::DVec3;
use harness::*;

fn die(msg: &str) -> ! {
    eprintln!("sim_run: {msg}");
    std::process::exit(2);
}

fn parse_raid(spec: &str) -> RaidSpec {
    let mut r = RaidSpec { kinds: Vec::new(), approach: Approach::Sector, aim: Aim::Smart, dist: 400.0, at: 1 };
    for (i, part) in spec.split(';').enumerate() {
        if i == 0 {
            for kc in part.split(',').filter(|s| !s.is_empty()) {
                let (k, c) = kc.split_once('=').unwrap_or_else(|| die(&format!("raid kind `{kc}` needs =count")));
                let kind = DroneKind::from_key(k).unwrap_or_else(|| die(&format!("unknown drone kind `{k}` (see --list)")));
                r.kinds.push((kind, c.parse().unwrap_or_else(|_| die(&format!("bad count `{c}`")))));
            }
            continue;
        }
        let (k, v) = part.split_once('=').unwrap_or_else(|| die(&format!("bad raid option `{part}`")));
        match k {
            "dist" => r.dist = v.parse().unwrap_or_else(|_| die("bad dist")),
            "at" => r.at = v.parse().unwrap_or_else(|_| die("bad at")),
            "aim" => {
                r.aim = match v {
                    "smart" => Aim::Smart,
                    "objects" => Aim::Objects,
                    "sams" => Aim::ObjectsAndSams,
                    _ => die("aim: smart | objects | sams"),
                }
            }
            "approach" => {
                r.approach = match v {
                    "sector" => Approach::Sector,
                    "two" => Approach::TwoSectors,
                    "all" => Approach::AllSides,
                    "waves" => Approach::Waves,
                    _ => die("approach: sector | two | all | waves"),
                }
            }
            _ => die(&format!("unknown raid option `{k}`")),
        }
    }
    r
}

fn parse_terrain(t: &str) -> Terrain {
    let n: Vec<&str> = t.split(':').collect();
    let num = |i: usize, d: f64| n.get(i).map_or(d, |s| s.parse().unwrap_or_else(|_| die("bad terrain number")));
    match n[0] {
        "flat" => Terrain::Flat(num(1, 70.0) as i32),
        "hills" => Terrain::Hills { base: num(1, 70.0) as i32, amp: num(2, 14.0), period: num(3, 90.0) },
        _ => die("terrain: flat[:H] | hills[:BASE:AMP:PERIOD]"),
    }
}

fn parse_layout(path: &str) -> Vec<Unit> {
    let text = std::fs::read_to_string(path).unwrap_or_else(|e| die(&format!("{path}: {e}")));
    let mut units = Vec::new();
    for (n, line) in text.lines().enumerate() {
        let line = line.split('#').next().unwrap_or("").trim();
        if line.is_empty() {
            continue;
        }
        let w: Vec<&str> = line.split_whitespace().collect();
        let bad = || die(&format!("{path}:{}: expected `KIND X Z [HEADING] [empty]`", n + 1));
        if w.len() < 3 {
            bad();
        }
        let kind = SamKind::from_key(w[0]).unwrap_or_else(|| die(&format!("{path}:{}: unknown system `{}`", n + 1, w[0])));
        let f = |s: &str| s.parse::<f64>().unwrap_or_else(|_| bad());
        let heading = w.get(3).filter(|s| **s != "empty").map_or(0.0, |s| f(s));
        units.push(Unit { kind, pos: DVec3::new(f(w[1]), 70.0, f(w[2])), heading, empty: w.contains(&"empty") });
    }
    units
}

pub fn main() {
    let args: Vec<String> = std::env::args().skip(1).collect();
    let mut name = "big-smart".to_string();
    let mut i = 0;
    // The scenario first, so the other options override it whatever their order.
    while i < args.len() {
        if args[i] == "--scenario" {
            name = args.get(i + 1).cloned().unwrap_or_else(|| die("--scenario needs a name"));
        }
        i += 1;
    }
    let mut sc = preset(&name).unwrap_or_else(|| die(&format!("unknown scenario `{name}`; one of {PRESETS:?}")));
    let (mut json, mut raids) = (false, Vec::new());
    let mut it = args.iter();
    while let Some(arg) = it.next() {
        let mut value = || it.next().cloned().unwrap_or_else(|| die(&format!("{arg} needs a value")));
        match arg.as_str() {
            "--scenario" => {
                value();
            }
            "--seed" => sc.seed = value().parse().unwrap_or_else(|_| die("bad seed")),
            "--ticks" => sc.ticks = value().parse().unwrap_or_else(|_| die("bad ticks")),
            "--layout" => sc.units = parse_layout(&value()),
            "--raid" => raids.push(parse_raid(&value())),
            "--terrain" => sc.terrain = parse_terrain(&value()),
            "--run-on" => sc.stop_at_end = false,
            "--ew" => sc.ew = true,
            "--no-ew" => sc.ew = false,
            "--json" => json = true,
            "--list" => {
                println!("scenarios: {PRESETS:?}");
                println!("systems: {:?}", SamKind::ALL.iter().map(|k| k.key()).collect::<Vec<_>>());
                println!("drones: {:?}", DroneKind::ALL.iter().map(|k| k.spec().key).collect::<Vec<_>>());
                return;
            }
            "-h" | "--help" => {
                println!("{}", include_str!("main.rs").lines().take_while(|l| l.starts_with("//")).map(|l| l.trim_start_matches("//!").trim_start_matches("//").to_string() + "\n").collect::<String>());
                return;
            }
            other => die(&format!("unknown option `{other}` (try --help)")),
        }
    }
    if !raids.is_empty() {
        sc.raids = raids;
    }
    let r = run(&sc);
    if json {
        println!("{}", r.json());
    } else {
        print!("{}", r.text());
    }
    let problems = r.problems();
    if !problems.is_empty() {
        eprintln!("PROBLEMS: {}", problems.join("; "));
        std::process::exit(1);
    }
}