wowsunpack 0.37.0

//! TTX factory functions: apply per-species formulas + the equipped
//! `ModifierBundle` to base component stats, producing unit-carrying `ShipStats`
//! sections. Formulas are transcribed verbatim from the deob; each is cited at
//! its application site.
//!
//! This module currently covers the direct-field species `durability` and
//! `mobility`; armor/battery/hull-summary land in later M2 tasks.

use crate::game_params::ttx::armor_materials::armor_type_classifies;
use crate::game_params::ttx::armor_materials::collision_material_name;
use crate::game_params::ttx::components::ArtilleryComponentStats;
use crate::game_params::ttx::components::EngineComponentStats;
use crate::game_params::ttx::components::HullComponentStats;
use crate::game_params::ttx::components::SecondaryComponentStats;
use crate::game_params::ttx::components::TorpedoLauncherStats;
use crate::game_params::ttx::constants;
use crate::game_params::ttx::constants::BW_TO_BALLISTIC;
use crate::game_params::ttx::constants::HULL_HEALTH_ROUND;
use crate::game_params::ttx::constants::KM_TO_M;
use crate::game_params::ttx::constants::TORPEDO_DAMAGE_CONSTANT;
use crate::game_params::ttx::model::AmmoCount;
use crate::game_params::ttx::model::Armor;
use crate::game_params::ttx::model::Artillery;
use crate::game_params::ttx::model::Battery;
use crate::game_params::ttx::model::DegreesPerSecond;
use crate::game_params::ttx::model::Durability;
use crate::game_params::ttx::model::Hp;
use crate::game_params::ttx::model::Knots;
use crate::game_params::ttx::model::Launcher;
use crate::game_params::ttx::model::MainGun;
use crate::game_params::ttx::model::Mobility;
use crate::game_params::ttx::model::Percent;
use crate::game_params::ttx::model::Seconds;
use crate::game_params::ttx::model::ShellStats;
use crate::game_params::ttx::model::TorpedoStats;
use crate::game_params::ttx::model::Torpedoes;
use crate::game_params::ttx::model::Visibility;
use crate::game_params::ttx::modifiers::ModifierBundle;
use crate::game_params::ttx::weapon_tables::StatWeaponType;
use crate::game_params::ttx::weapon_tables::alpha_damage_coeff;
use crate::game_params::ttx::weapon_tables::ammo_to_stat_weapon_table;
use crate::game_params::ttx::weapon_tables::artillery_damage_coeff;
use crate::game_params::ttx::weapon_tables::calculate_burn_chance;
use crate::game_params::ttx::weapon_tables::is_small_projectile;
use crate::game_params::types::ArmorMap;
use crate::game_params::types::GameParamProvider;
use crate::game_params::types::Km;
use crate::game_params::types::Meters;
use crate::game_params::types::Millimeters;
use crate::game_params::types::Projectile;

/// `AMMO_TYPES.TORPEDO` string discriminant (ProjectileConstants.py:13), the gate
/// for `normalTorpedoSpeedMultiplier` in `getTorpedoSpeed` (ModifiersApply.py:495).
const AMMO_TYPE_TORPEDO: &str = "torpedo";

/// `TORPEDO_TYPE.COMMON = 0` (shared_constants/mbe76a59e.py:517), the value tested by
/// `disabledUnderwater` (FactoryTorpedoes.py:101).
const TORPEDO_TYPE_COMMON: i64 = 0;

/// Survivability section (`ma6320f36/ttx/FactoryDurability.py:5`).
///
/// `health` transcribes `Modifiers/ModifiersApply.py:142`'s `calculateVehicleHealth`:
/// `(hull.health + healthPerLevel*level) * healthHullCoeff`, then rounded up to a
/// multiple of `HULL_HEALTH_ROUND` (line 143). `healthPerLevel` is additive
/// (base_value 0.0 -> `bonus`); `healthHullCoeff` is multiplicative (base_value 1.0
/// -> `coef`).
///
/// `torpedo_protection` (ptz, FactoryDurability.py:8) is
/// `hull.floodProb * uwCoeffMultiplier * 100 + uwCoeffBonus`. `floodProb` is derived
/// at parse time from `floodNodes` (HullComponentStats::flood_prob, PreprocessedHull.py:12);
/// `uwCoeffMultiplier` is a coefficient (`*`) and `uwCoeffBonus` an additive bonus (`+`,
/// MODIFIER_SETTINGS base_value 0.0). `None` when `flood_prob` is absent.
pub fn durability(hull: &HullComponentStats, modifiers: &ModifierBundle, level: u32) -> Durability {
    let health = hull.health.map(|base| {
        let raw = (base.value() + modifiers.bonus("healthPerLevel") * level as f32) * modifiers.coef("healthHullCoeff");
        // ceil(raw / round) * round (ModifiersApply.py:143).
        let rounded = (raw / HULL_HEALTH_ROUND).ceil() * HULL_HEALTH_ROUND;
        Hp::from(rounded)
    });

    let torpedo_protection = hull.flood_prob.map(|prob| {
        Percent::from(prob * modifiers.coef("uwCoeffMultiplier") * 100.0 + modifiers.bonus("uwCoeffBonus"))
    });

    Durability { health, torpedo_protection }
}

/// Maneuverability section (`ma6320f36/ttx/FactoryMobility.py:6`).
///
/// `speed` = `calculateMaxSpeedKnots(prepared) * speedCoef` (FactoryMobility.py:8),
/// where `calculateMaxSpeedKnots` (ShipParams.py:348) is
/// `hull.maxSpeed * clamp(hull.speedCoef + engine.speedCoef, 0.0, 1.0)`. `speedCoef`
/// is multiplicative (base_value 1.0 -> `coef`).
///
/// `turning_radius` = `hull.turningRadius` directly (FactoryMobility.py:9, no modifier).
///
/// `rudder_time` = `hull.rudderTime * SGRudderTime` (FactoryMobility.py:10).
/// `SGRudderTime` is multiplicative (base_value 1.0 -> `coef`).
pub fn mobility(hull: &HullComponentStats, engine: &EngineComponentStats, modifiers: &ModifierBundle) -> Mobility {
    let speed = match (hull.max_speed, hull.speed_coef) {
        (Some(max_speed), Some(hull_speed_coef)) => {
            let engine_speed_coef = engine.speed_coef.unwrap_or(0.0);
            let coef = (hull_speed_coef + engine_speed_coef).clamp(0.0, 1.0);
            Some(Knots::from(max_speed.value() * coef * modifiers.coef("speedCoef")))
        }
        _ => None,
    };

    let turning_radius = hull.turning_radius;

    let rudder_time = hull.rudder_time.map(|t| Seconds::from(t.value() * modifiers.coef("SGRudderTime")));

    Mobility { speed, turning_radius, rudder_time }
}

/// Submarine battery section (`ma6320f36/ttx/FactoryBattery.py:4`).
///
/// `capacity = hull.batteryCapacity * batteryCapacityCoeff` (FactoryBattery.py:10),
/// `regeneration = hull.batteryRegenRate * batteryRegenCoeff` (FactoryBattery.py:11).
/// Both coeffs are multiplicative (MODIFIER_SETTINGS base_value 1.0). The deob returns
/// `None` when `batteryCapacity == 0` (FactoryBattery.py:5); here the hull carries
/// battery fields only for submarines, so `None` when they are absent.
pub fn battery(hull: &HullComponentStats, modifiers: &ModifierBundle) -> Option<Battery> {
    let (capacity, regen) = (hull.battery_capacity?, hull.battery_regen_rate?);
    if capacity == 0.0 {
        return None;
    }
    Some(Battery {
        capacity: Some(capacity * modifiers.coef("batteryCapacityCoeff")),
        regeneration: Some(regen * modifiers.coef("batteryRegenCoeff")),
    })
}

/// Default lowest armor thickness when an `armorList` yields no classified plate
/// (`PreprocessedArmor.py:8`'s `armorMin`/`armorMax` seed, `ArmorConstants.py`
/// `DEFAULT_LOWEST_ARMOR_THICKNESS`).
const DEFAULT_LOWEST_ARMOR_THICKNESS: f32 = 6.0;

/// Reduce one `armorList` (an [`ArmorMap`]) to its `(min, max)` over the plates
/// `getArmorType` classifies, transcribing `PreprocessedArmor.__init__`
/// (`PreprocessedArmor.py:7-15`).
///
/// The deob filter is `[thk for matId, thk in armorList.items()
/// if getArmorType(collisionMaterialName(matId)) if thk > 0]`. The collision
/// material id is the low byte of the outer key (`Avatar.py:1386` masks `& 255`;
/// `getGunArmorBits`/`gunArmorMask` reserve the other bits for gun/model
/// indices). When no plate is classified, both extremes are
/// `DEFAULT_LOWEST_ARMOR_THICKNESS`.
fn armor_list_min_max(armor: &ArmorMap) -> (f32, f32) {
    let mut min = DEFAULT_LOWEST_ARMOR_THICKNESS;
    let mut max = DEFAULT_LOWEST_ARMOR_THICKNESS;
    let mut found = false;

    for (&material_key, layers) in armor {
        let material_id = (material_key & 0xFF) as u8;
        if !armor_type_classifies(collision_material_name(material_id)) {
            continue;
        }
        for &thickness in layers.values() {
            if thickness <= 0.0 {
                continue;
            }
            if found {
                min = min.min(thickness);
                max = max.max(thickness);
            } else {
                min = thickness;
                max = thickness;
                found = true;
            }
        }
    }

    (min, max)
}

/// Armor section (`ma6320f36/ttx/FactoryArmor.py:5` `createArmorTTX`).
///
/// `min`/`max` are the extremes of classified plate thicknesses across the hull
/// `armorList` and, when the ship has artillery, the combined artillery
/// `armorList` (`getArmorDictByComponent`, all gun mounts). Per
/// `FactoryArmor.py:7-12`: with artillery, `min = min(arti.min, hull.min)` and
/// `max = max(arti.max, hull.max)`; otherwise hull-only.
///
/// `hull_armor` is the selected hull's `module.armor` (= `Vehicle.armor`).
/// `artillery_armor` yields each main-battery mount's armor map
/// (`MountPoint::mount_armor`); an empty iterator is the no-artillery branch.
/// `None` when the hull carries no armor data.
pub fn armor<'a>(hull_armor: &ArmorMap, artillery_armor: impl IntoIterator<Item = &'a ArmorMap>) -> Option<Armor> {
    if hull_armor.is_empty() {
        return None;
    }

    let (hull_min, hull_max) = armor_list_min_max(hull_armor);

    let mut arti_min: Option<f32> = None;
    let mut arti_max: Option<f32> = None;
    for map in artillery_armor {
        let (m, x) = armor_list_min_max(map);
        arti_min = Some(arti_min.map_or(m, |cur: f32| cur.min(m)));
        arti_max = Some(arti_max.map_or(x, |cur: f32| cur.max(x)));
    }

    let (min, max) = match (arti_min, arti_max) {
        (Some(amin), Some(amax)) => (amin.min(hull_min), amax.max(hull_max)),
        _ => (hull_min, hull_max),
    };

    Some(Armor { min: Some(Millimeters::from(min)), max: Some(Millimeters::from(max)) })
}

/// Per-ammo torpedo stats from a resolved [`Projectile`] (`createTorpedoTTX`,
/// FactoryTorpedoes.py:82-122). Pure over the projectile + bundle so the formulas
/// are testable without a provider. `name` is filled by the caller (the launcher's
/// `ammoList` entry); `disabled_underwater` is left `None` here (surface-ship path,
/// FactoryTorpedoes.py:100-101 gates it on `isSubmarine`).
///
/// Each field is `None` when its base projectile input is absent.
pub fn torpedo_stats(name: String, projectile: &Projectile, modifiers: &ModifierBundle) -> TorpedoStats {
    // damage: getTorpedoDamage (ModifiersApply.py:477-488). Surface torpedoes take
    // the `alphaDamage / TORPEDO_DAMAGE_CONSTANT` branch (line 484); the submarine
    // citadel branch (line 480) needs SubmarineTorpedoParams not modeled here.
    // controllableWeaponDamageCoeff applies to all torpedoes (line 488, ungated).
    let damage = match (projectile.alpha_damage(), projectile.damage()) {
        (Some(alpha), Some(flood)) => {
            let base = alpha / TORPEDO_DAMAGE_CONSTANT + flood;
            Some(Hp::from(
                base * modifiers.coef("torpedoDamageCoeff") * modifiers.coef("controllableWeaponDamageCoeff"),
            ))
        }
        _ => None,
    };

    // speed: getTorpedoSpeed (ModifiersApply.py:491-499). normalTorpedoSpeedMultiplier
    // only applies when ammoType == AMMO_TYPES.TORPEDO (line 495); deep-water/alt
    // torpedoes skip it (multiplier stays 1.0).
    let speed = projectile.speed().map(|s| {
        let normal = if projectile.ammo_type() == AMMO_TYPE_TORPEDO {
            modifiers.coef("normalTorpedoSpeedMultiplier")
        } else {
            1.0
        };
        Knots::from(s * modifiers.coef("torpedoSpeedMultiplier") * normal + modifiers.bonus("torpedoSpeedBonus"))
    });

    // range: maxDist * torpedoRangeCoefficient * BW_TO_BALLISTIC / KM_TO_M (FactoryTorpedoes.py:93).
    let range = projectile
        .max_dist()
        .map(|d| Km::from(d.value() * modifiers.coef("torpedoRangeCoefficient") * BW_TO_BALLISTIC / KM_TO_M));

    // visibility: visibilityFactor * torpedoVisibilityFactor (FactoryTorpedoes.py:92).
    let visibility = projectile.visibility_factor().map(|v| Km::from(v * modifiers.coef("torpedoVisibilityFactor")));

    // isDamageIncreasing: distanceOfDamage max-coeff dist > min-coeff dist (FactoryTorpedoes.py:103-120).
    // distanceOfMaxDamage (line 119) also needs ammoParams.armingTime/maneuverDist,
    // which are not on the parsed Projectile, so it stays None (no fabrication).
    let is_damage_increasing = projectile.distance_of_damage().filter(|d| !d.is_empty()).map(|pairs| {
        let coeff_at_min_dist = pairs.iter().min_by(|a, b| a.1.total_cmp(&b.1)).map(|p| p.0).unwrap_or(0.0);
        let coeff_at_max_dist = pairs.iter().max_by(|a, b| a.1.total_cmp(&b.1)).map(|p| p.0).unwrap_or(0.0);
        coeff_at_max_dist > coeff_at_min_dist
    });

    TorpedoStats {
        name,
        damage,
        speed,
        range,
        visibility,
        distance_of_max_damage: None,
        is_damage_increasing,
        disabled_underwater: None,
    }
}

/// Torpedo armament section (`createTorpedoesTTX`, FactoryTorpedoes.py:12-24).
///
/// `launchers` mirror `createLauncherTTX` (FactoryTorpedoes.py:74-80):
/// `rotation_speed = rotationSpeed[0] * GTRotationSpeed + GTRotationSpeedBonus`,
/// `rotation_time = 180 / rotation_speed`. FactoryTorpedoes.py:78 reads the
/// `GunRotationSpeedModifiersStruct` fields `yawSpeedCoef`/`yawSpeedBonus`, which
/// ModifiersApply.py:123 builds from `modifier.GTRotationSpeed`/`GTRotationSpeedBonus`
/// (GunRotationSpeed.py:10-13 positional->field map); the bundle is keyed by the
/// real modifier names, so we look up `GTRotationSpeed`/`GTRotationSpeedBonus`.
/// `reload_time` is the launcher reload
/// `shotDelay * GTShotDelay` (createUngroupedLaunchersTTX, FactoryTorpedoes.py:49)
/// aggregated as the `min` non-zero across mounts (initAmmoReloadParams,
/// FactoryTorpedoes.py:40). Per-ammo stats are resolved by NAME from `provider`
/// (`createTorpedoTTX`, FactoryTorpedoes.py:88-89).
///
/// Warn once per ammo name that an `ammoList` entry did not resolve to a
/// projectile, so the dropped shell/torpedo row is debuggable. Mirrors the
/// warn-once pattern in `armor_materials::collision_material_name`.
fn warn_unresolved_ammo(name: &str) {
    use std::collections::HashSet;
    use std::sync::Mutex;
    static WARNED: Mutex<Option<HashSet<String>>> = Mutex::new(None);

    let mut warned = WARNED.lock().unwrap();
    if warned.get_or_insert_with(HashSet::new).insert(name.to_string()) {
        eprintln!("TTX: ammo '{name}' did not resolve to a projectile; shell/torpedo row dropped");
    }
}

/// `None` when `launchers` is empty (no torpedo armament).
pub fn torpedoes(
    launchers: &[TorpedoLauncherStats],
    modifiers: &ModifierBundle,
    provider: &dyn GameParamProvider,
) -> Option<Torpedoes> {
    if launchers.is_empty() {
        return None;
    }

    // Real modifier names behind GunRotationSpeedModifiersStruct.yawSpeedCoef/yawSpeedBonus
    // (GunRotationSpeed.py:10-13, ModifiersApply.py:123).
    let yaw_coef = modifiers.coef("GTRotationSpeed");
    let yaw_bonus = modifiers.bonus("GTRotationSpeedBonus");
    let shot_delay_coef = modifiers.coef("GTShotDelay");

    let mut result_launchers = Vec::with_capacity(launchers.len());
    let mut reload_times: Vec<f32> = Vec::new();
    let mut seen_ammo: Vec<String> = Vec::new();
    let mut torpedoes = Vec::new();

    for launcher in launchers {
        let rotation_speed = launcher.rotation_speed.map(|r| r.value() * yaw_coef + yaw_bonus);
        let rotation_time = rotation_speed.filter(|&r| r != 0.0).map(|r| Seconds::from(180.0 / r));
        result_launchers.push(Launcher {
            rotation_speed: rotation_speed.map(DegreesPerSecond::from),
            rotation_time,
            num_barrels: launcher.num_barrels.map(|n| n as u32),
        });

        if let Some(delay) = launcher.shot_delay {
            let reload = delay.value() * shot_delay_coef;
            if reload != 0.0 {
                reload_times.push(reload);
            }
        }

        for ammo_name in &launcher.ammo {
            if seen_ammo.iter().any(|n| n == ammo_name) {
                continue;
            }
            seen_ammo.push(ammo_name.clone());
            if let Some(param) = provider.game_param_by_name(ammo_name)
                && let Some(projectile) = param.projectile()
            {
                torpedoes.push(torpedo_stats(ammo_name.clone(), projectile, modifiers));
            } else {
                warn_unresolved_ammo(ammo_name);
            }
        }
    }

    let reload_time = reload_times.iter().copied().reduce(f32::min).map(Seconds::from);

    Some(Torpedoes { reload_time, launchers: result_launchers, torpedoes })
}

/// Caliber threshold constants (`me658a8e4.py:13,15`) are zeroed placeholders in
/// every deob source; the real values live in a compiled C++ module. Stock results
/// are unaffected (the gated coeffs read identity 1.0/0.0 from an empty bundle).
/// Passed as `0.0` here, matching the weapon_tables test convention.
const HEAVY_CRUISER_SHELL_DIAMETER_M: f32 = 0.0;
const SMALL_PROJECTILE_MAX_DIAMETER_M: f32 = 0.0;

/// Per-shell stats from a resolved [`Projectile`] (`createAmmoTTX`,
/// FactoryArtillery.py:147-190). Pure over the projectile + bundle so the formulas
/// are testable without a provider. `level` is the ship tier (burn-chance branch,
/// ModifiersApply.py:43); main-battery shells take `max_ammo = Infinite` (the main
/// `getPreprocessedAmmoList` call passes no pool info, PreprocessedArtillery.py:33,
/// so every pool is `INFINITE_AMMO_POOL_SIZE = -1`, PreprocessedAmmo.py:6).
///
/// `is_atba` selects the secondary-battery path (FactoryArtillery.py:159-161): the
/// resolved [`StatWeaponType`] is mapped through `to_atba()` so `getAlphaDamageCoeff`
/// (ModifiersApply.py:459-463) and `getArtilleryDamageCoeff` (ModifiersApply.py:380-388)
/// read the `GS*` coefficients, and HE penetration uses `GSPenetrationCoeffHE`
/// (FactoryArtillery.py:175) rather than `GMPenetrationCoeffHE`.
///
/// Each field is `None` when its base projectile input is absent.
pub fn shell_stats(
    name: String,
    projectile: &Projectile,
    modifiers: &ModifierBundle,
    level: u32,
    is_atba: bool,
) -> ShellStats {
    let ammo_kind = projectile.ammo_type();
    let mut weapon = ammo_to_stat_weapon_table(ammo_kind);
    if is_atba {
        // FactoryArtillery.py:159-161: map the main stat type to its ATBA equivalent.
        weapon = weapon.to_atba();
    }

    // caliber * 1000 (FactoryArtillery.py:155). caliber (m) = bulletDiametr.
    let caliber_m = projectile.bullet_diametr();
    let caliber = caliber_m.map(|c| Millimeters::from(c * 1000.0));

    // speed = bulletSpeed * timeFactor (PreprocessedAmmo.py:16). timeFactor defaults to
    // 1.0 when absent (maa3520d6.py:1151, GameParams class attribute); most shells omit it,
    // but PXPA* event shells carry 0.5/0.75/2.2.
    let speed = projectile.bullet_speed().map(|s| s * projectile.time_factor().unwrap_or(1.0));

    // damage = alphaDamage * getAlphaDamageCoeff * controllableWeaponDamageCoeff
    //   * getArtilleryDamageCoeff * citadelCSAP(if weapon in WEAPONS_CSAP)
    // (FactoryArtillery.py:164). isManualATBA factor (line 156/164 `unknown_42`) is 1.0
    // on the main path. Stock coeffs are 1.0, so damage reduces to alphaDamage.
    let damage = match (projectile.alpha_damage(), caliber_m) {
        (Some(alpha), Some(cal_m)) => {
            let csap = if weapon.is_csap() { modifiers.coef("citadelDamageMultiplierCSAP") } else { 1.0 };
            let value = alpha
                * alpha_damage_coeff(weapon, modifiers, false)
                * modifiers.coef("controllableWeaponDamageCoeff")
                * artillery_damage_coeff(cal_m, weapon, modifiers, HEAVY_CRUISER_SHELL_DIAMETER_M)
                * csap;
            Some(Hp::from(value))
        }
        _ => None,
    };

    // piercing: HE floor(alphaPiercingHE * penetrationCoeffHE) (FactoryArtillery.py:182);
    // the coef is GMPenetrationCoeffHE for main, GSPenetrationCoeffHE for ATBA
    // (FactoryArtillery.py:175/180). CS floor(alphaPiercingCS) (line 185); AP is a
    // ballistic sim (no closed form) -> None.
    let he_pen_coef =
        if is_atba { modifiers.coef("GSPenetrationCoeffHE") } else { modifiers.coef("GMPenetrationCoeffHE") };
    let penetration = match weapon {
        StatWeaponType::MainHe | StatWeaponType::AtbaHe => {
            projectile.alpha_piercing_he().map(|p| Millimeters::from((p * he_pen_coef).floor()))
        }
        StatWeaponType::MainCs | StatWeaponType::AtbaCs => {
            projectile.alpha_piercing_cs().map(|p| Millimeters::from(p.floor()))
        }
        _ => None,
    };

    // burnChance: calculateBurnChance(level, burnProb) for HE (line 171) and AP (line 188);
    // CS sets no burnChance. burnProb -0.5 (AP "N/A") clamps to 0 in calculate_burn_chance.
    // Stored as a percent (burnProb 0.12 -> 12%).
    let is_small = caliber_m.is_some_and(|c| is_small_projectile(c, SMALL_PROJECTILE_MAX_DIAMETER_M));
    let burn_chance = match weapon {
        StatWeaponType::MainHe | StatWeaponType::MainAp | StatWeaponType::AtbaHe | StatWeaponType::AtbaAp => projectile
            .burn_prob()
            .map(|bp| Percent::from(calculate_burn_chance(level, bp, modifiers, is_small) * 100.0)),
        _ => None,
    };

    // floodChance = uwCritical, HE only (FactoryArtillery.py:172). Stored as a percent.
    let flood_chance = match weapon {
        StatWeaponType::MainHe | StatWeaponType::AtbaHe => projectile.uw_critical().map(|f| Percent::from(f * 100.0)),
        _ => None,
    };

    ShellStats {
        name,
        ammo_kind: Some(ammo_kind.to_string()),
        damage,
        caliber,
        speed,
        penetration,
        burn_chance,
        flood_chance,
        // Main battery pools are unlimited (INFINITE_AMMO_POOL_SIZE -> Infinite).
        max_ammo: Some(AmmoCount::Infinite),
        // Deferred: FactoryArtillery.py:165 sets this from the hull's canBeUnderwater,
        // which is not threaded into this projectile-only path.
        disabled_underwater: None,
    }
}

/// Main-battery armament section (`ArtilleryTTX`, FactoryArtillery.py + TTXFactory.py).
///
/// `reload_time` = `gun.shotDelay * GMShotDelay` (FactoryArtillery.py:32 alt-fire analog;
/// the per-gun reload). `range` = `(maxDist / KM_TO_M) * fcMaxDistCoef * GMMaxDist`
/// (FactoryArtillery.py:42; `maxDist` is the component BigWorld range,
/// PreprocessedArtillery.py:32 divides by `KM_TO_M`). `dispersion` =
/// `getDispersionValue(gun, range_km, GMIdealRadius)` over the FC-adjusted range
/// (FactoryArtillery.py:47 passes the `* GMMaxDist`-scaled `unknown_12`).
/// `ammo_switch_time` = `shotDelay * ammoSwitchCoeff * GMShotDelay * switchAmmoReloadCoef`
/// (Components/Artillery.py:311, `ammoSwitchCoeff * switchAmmoReloadCoef`).
///
/// The gun (`MainGun`) mirrors `createMainGunTTX` (FactoryArtillery.py:70-76) +
/// `initGunTTX` (PreprocessedGun.py:18-23):
/// `rotation_speed = rotationSpeed[0] * GMRotationSpeed + GMRotationSpeedBonus`,
/// `rotation_time = 180 / rotation_speed`, `caliber = barrelDiameter * 1000`,
/// `num_barrels = gp.numBarrels`, `num_guns = HP_AGM mount count`.
///
/// `fc_max_dist_coef` is the fire-control `maxDistCoef` (FactoryArtillery.py:42, default
/// 1.0; M5 supplies the real value). `None` when the component has no guns.
pub fn artillery(
    arty: &ArtilleryComponentStats,
    modifiers: &ModifierBundle,
    fc_max_dist_coef: f32,
    level: u32,
    provider: &dyn GameParamProvider,
) -> Option<Artillery> {
    if arty.guns.is_empty() {
        return None;
    }

    let shot_delay_coef = modifiers.coef("GMShotDelay");
    let max_dist_coef = modifiers.coef("GMMaxDist");
    let ideal_radius_coef = modifiers.coef("GMIdealRadius");
    let switch_coef = modifiers.coef("switchAmmoReloadCoef");
    let yaw_coef = modifiers.coef("GMRotationSpeed");
    let yaw_bonus = modifiers.bonus("GMRotationSpeedBonus");

    // All main-battery mounts share the same reload; take the first gun's shotDelay.
    let first = &arty.guns[0];

    let reload_time = first.shot_delay.map(|d| Seconds::from(d.value() * shot_delay_coef));

    let range_km = arty.max_dist.map(|d| (d.value() / KM_TO_M) * fc_max_dist_coef * max_dist_coef);
    let range = range_km.map(Km::from);

    // dispersion over the FC-adjusted range (FactoryArtillery.py:47 uses `unknown_12`).
    let dispersion = match (range_km, first.min_radius, first.ideal_radius, first.ideal_distance) {
        (Some(rng), Some(min_r), Some(ideal_r), Some(ideal_d)) => {
            Some(Meters::from(constants::dispersion(min_r, ideal_r, ideal_d, rng, ideal_radius_coef)))
        }
        _ => None,
    };

    let ammo_switch_time = match (first.shot_delay, first.ammo_switch_coeff) {
        (Some(delay), Some(coeff)) => Some(Seconds::from(delay.value() * coeff * shot_delay_coef * switch_coef)),
        _ => None,
    };

    let rotation_speed = first.rotation_speed.map(|r| r.value() * yaw_coef + yaw_bonus);
    let rotation_time = rotation_speed.filter(|&r| r != 0.0).map(|r| Seconds::from(180.0 / r));
    let gun = Some(MainGun {
        caliber: first.barrel_diameter.map(|b| b.to_mm()),
        num_barrels: first.num_barrels.map(|n| n as u32),
        num_guns: Some(arty.guns.len() as u32),
        rotation_speed: rotation_speed.map(DegreesPerSecond::from),
        rotation_time,
    });

    // Shell stats resolved by NAME from the first gun's ammoList (all mounts share ammo).
    let mut shells = Vec::new();
    let mut seen: Vec<String> = Vec::new();
    for ammo_name in &first.ammo {
        if seen.iter().any(|n| n == ammo_name) {
            continue;
        }
        seen.push(ammo_name.clone());
        if let Some(param) = provider.game_param_by_name(ammo_name)
            && let Some(projectile) = param.projectile()
        {
            shells.push(shell_stats(ammo_name.clone(), projectile, modifiers, level, false));
        } else {
            warn_unresolved_ammo(ammo_name);
        }
    }

    Some(Artillery { reload_time, range, dispersion, ammo_switch_time, gun, shells })
}

/// Secondary-battery (ATBA) armament section (`createATBAGunTTX`,
/// FactoryArtillery.py:79-87). Mirrors [`artillery`] but reads the `GS*` modifier
/// coefficients and resolves shells through the ATBA stat-weapon path.
///
/// `reload_time` = `gun.shotDelay * GSShotDelay` (FactoryArtillery.py:83).
/// `range` = `atba.maxDist * GSMaxDist` (FactoryArtillery.py:84). The deob's
/// `atba.maxDist` is in KM (PreprocessedATBA.py:30 stores `module.maxDist / KM_TO_M`);
/// [`SecondaryComponentStats::max_dist`] keeps the raw BigWorld value, so this divides
/// by `KM_TO_M` here. Secondaries have no fire-control `maxDistCoef`
/// (FactoryArtillery.py:84 omits it, unlike the main-battery line 42).
/// `dispersion` = `getDispersionValue(gun, range_km, GSIdealRadius)` over that range
/// (FactoryArtillery.py:84). The gun `rotation_speed` =
/// `rotationSpeed[0] * GSRotationSpeed + GSRotationSpeedBonus` (initGunTTX +
/// createMainGunTTX analog, FactoryArtillery.py:74 with the GS coefficient names).
///
/// Secondaries mount mixed calibers (e.g. Bismarck's 150mm + 105mm guns), so the deob
/// builds a per-gun-group `ATBAGunTTX` list (ArtilleryTTX.atba) sharing one
/// component-level `atbaMaxDist`. This single-[`Artillery`] view takes the first gun
/// group for `reload_time`/`gun` (as [`artillery`] does for main mounts) and lists a
/// shell per distinct ATBA ammo name across all mounts; `range`/`dispersion` use the
/// component `maxDist`. `None` when the component has no guns.
pub fn secondaries(
    atba: &SecondaryComponentStats,
    modifiers: &ModifierBundle,
    level: u32,
    provider: &dyn GameParamProvider,
) -> Option<Artillery> {
    if atba.guns.is_empty() {
        return None;
    }

    let shot_delay_coef = modifiers.coef("GSShotDelay");
    let max_dist_coef = modifiers.coef("GSMaxDist");
    let ideal_radius_coef = modifiers.coef("GSIdealRadius");
    let yaw_coef = modifiers.coef("GSRotationSpeed");
    let yaw_bonus = modifiers.bonus("GSRotationSpeedBonus");

    // First gun group drives the displayed reload/gun (FactoryArtillery.py:83 is per gun).
    let first = &atba.guns[0];

    let reload_time = first.shot_delay.map(|d| Seconds::from(d.value() * shot_delay_coef));

    // range = (maxDist / KM_TO_M) * GSMaxDist (FactoryArtillery.py:84 over the KM
    // maxDist of PreprocessedATBA.py:30). No fire-control coef for secondaries.
    let range_km = atba.max_dist.map(|d| (d.value() / KM_TO_M) * max_dist_coef);
    let range = range_km.map(Km::from);

    let dispersion = match (range_km, first.min_radius, first.ideal_radius, first.ideal_distance) {
        (Some(rng), Some(min_r), Some(ideal_r), Some(ideal_d)) => {
            Some(Meters::from(constants::dispersion(min_r, ideal_r, ideal_d, rng, ideal_radius_coef)))
        }
        _ => None,
    };

    let rotation_speed = first.rotation_speed.map(|r| r.value() * yaw_coef + yaw_bonus);
    let rotation_time = rotation_speed.filter(|&r| r != 0.0).map(|r| Seconds::from(180.0 / r));
    let gun = Some(MainGun {
        caliber: first.barrel_diameter.map(|b| b.to_mm()),
        num_barrels: first.num_barrels.map(|n| n as u32),
        num_guns: Some(atba.guns.len() as u32),
        rotation_speed: rotation_speed.map(DegreesPerSecond::from),
        rotation_time,
    });

    // One shell per distinct ATBA ammo name across every mount (mixed calibers).
    let mut shells = Vec::new();
    let mut seen: Vec<String> = Vec::new();
    for gun_stats in &atba.guns {
        for ammo_name in &gun_stats.ammo {
            if seen.iter().any(|n| n == ammo_name) {
                continue;
            }
            seen.push(ammo_name.clone());
            if let Some(param) = provider.game_param_by_name(ammo_name)
                && let Some(projectile) = param.projectile()
            {
                shells.push(shell_stats(ammo_name.clone(), projectile, modifiers, level, true));
            } else {
                warn_unresolved_ammo(ammo_name);
            }
        }
    }

    Some(Artillery {
        reload_time,
        range,
        dispersion,
        // Secondaries have no ammo switch (single shell type per gun, FactoryArtillery.py omits it).
        ammo_switch_time: None,
        gun,
        shells,
    })
}

/// `MINIMAL_VALID_VALUE` smoke-detection gate (createVisibilityTTX@140): the in-smoke
/// range is shown only when `visibilityCoefGKInSmoke` exceeds it. The compiled module
/// that defines the constant carries 0.01; below it the field is a zeroed placeholder.
const MINIMAL_VALID_VALUE: f32 = 0.01;

/// Detectability section (`ma6320f36/ttx/FactoryVisibility.pyc` createVisibilityTTX,
/// offsets from the bytecode disassembly).
///
/// `coeff` (@21,@49-58) = `mod.visibilityDistCoeff`, multiplied by
/// `mod.GMBigGunVisibilityCoeff` when the ship has non-small artillery
/// (`artillery and not artillery.isSmall`, @30-58); `has_big_gun_artillery` is that
/// gate. Both modifiers are coefficients (MODIFIER_SETTINGS base_value 1.0).
///
/// `sea_detection` (@65-94) = `hull.visibilityFactor * mod.visibilityFactor * coeff`.
/// `sea_detection_on_fire` (@97-128) = `sea + hull.visibilityCoefFire`.
/// `detection_in_smoke` (@131-167) = `hull.visibilityCoefGKInSmoke`, only when it
/// exceeds `MINIMAL_VALID_VALUE`. `air_detection` (@278-307) =
/// `hull.visibilityFactorByPlane * mod.visibilityFactorByPlane * coeff`;
/// `air_detection_on_fire` (@310-341) = `air + hull.visibilityCoefFireByPlane`.
/// `secondary_range_detection` (@227-272) = `max(sea, atbaMaxDist)` when the secondary
/// range is supplied; the MG floor (`max(sea, mgMaxDist)`, @173-224) folds into the same
/// field via `mg_max_dist_km`. `periscope_depth_detection` (@359-384) =
/// `hull.visibilityByPeriscope * mod.visibilityForSubmarineCoeff`, present only for subs.
///
/// Per-depth submarine ranges (`byDepth`, @387-513) are a runtime entity calc
/// (`ShipParams.getVehicleParams` + `getPerDepthRangeVisiblity`) and are deferred.
///
/// Each field is `None` when its base hull input is absent.
pub fn visibility(
    hull: &HullComponentStats,
    modifiers: &ModifierBundle,
    has_big_gun_artillery: bool,
    mg_max_dist_km: Option<f32>,
    atba_max_dist_km: Option<f32>,
) -> Visibility {
    let mut coeff = modifiers.coef("visibilityDistCoeff");
    if has_big_gun_artillery {
        coeff *= modifiers.coef("GMBigGunVisibilityCoeff");
    }

    let sea = hull.visibility_factor.map(|v| v.value() * modifiers.coef("visibilityFactor") * coeff);
    let sea_detection = sea.map(Km::from);

    let sea_detection_on_fire = match (sea, hull.visibility_coef_fire) {
        (Some(s), Some(fire)) => Some(Km::from(s + fire.value())),
        _ => None,
    };

    let detection_in_smoke =
        hull.visibility_coef_gk_in_smoke.filter(|&v| v.value() > MINIMAL_VALID_VALUE).map(|v| Km::from(v.value()));

    // mgMaxDist and atbaMaxDist both write the same secondary-detection floor; take the
    // max over whichever ranges are supplied, floored by `sea` (@188-272).
    let secondary_range_detection = match (sea, mg_max_dist_km, atba_max_dist_km) {
        (Some(s), mg, atba) if mg.is_some() || atba.is_some() => {
            let floor = mg.unwrap_or(s).max(atba.unwrap_or(s));
            Some(Km::from(s.max(floor)))
        }
        _ => None,
    };

    let air = hull.visibility_factor_by_plane.map(|v| v.value() * modifiers.coef("visibilityFactorByPlane") * coeff);
    let air_detection = air.map(Km::from);

    let air_detection_on_fire = match (air, hull.visibility_coef_fire_by_plane) {
        (Some(a), Some(fire)) => Some(Km::from(a + fire.value())),
        _ => None,
    };

    let periscope_depth_detection = hull
        .visibility_factor_by_periscope
        .map(|v| Km::from(v.value() * modifiers.coef("visibilityForSubmarineCoeff")));

    Visibility {
        sea_detection,
        sea_detection_on_fire,
        air_detection,
        air_detection_on_fire,
        detection_in_smoke,
        secondary_range_detection,
        periscope_depth_detection,
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::game_params::ttx::components::ArtilleryGunStats;
    use crate::game_params::ttx::constants::DEFAULT_UW_DAMAGE_COEFF;
    use crate::game_params::types::CrewSkillModifier;
    use crate::game_params::types::Species;

    /// The build whose `MODIFIER_SETTINGS` table is transcribed in the toolkit.
    const BUILD: u32 = 11791718;

    /// Gearing's real default-hull base stats (GameParams `PASD013_Gearing_1945`
    /// `A_Hull`): health 19400, maxSpeed 36, speedCoef 1.0, turningRadius 640,
    /// rudderTime 4.25, visibilityFactor 7.33. `floodNodes[0][0]` is 0.333 (==
    /// DEFAULT_UW_DAMAGE_COEFF), so flood_prob is 0.0; no SubmarineBattery (DD).
    fn gearing_hull() -> HullComponentStats {
        HullComponentStats {
            health: Some(Hp::from(19400.0)),
            max_speed: Some(Knots::from(36.0)),
            speed_coef: Some(1.0),
            turning_radius: Some(Meters::from(640.0)),
            rudder_time: Some(Seconds::from(4.25)),
            visibility_factor: Some(Km::from(7.33)),
            visibility_factor_by_plane: Some(Km::from(3.41)),
            visibility_coef_fire: Some(Km::from(2.0)),
            visibility_coef_fire_by_plane: Some(Km::from(2.0)),
            visibility_coef_gk: Some(Km::from(1e-6)),
            visibility_coef_gk_in_smoke: Some(Km::from(2.83)),
            visibility_factor_by_periscope: None,
            flood_prob: Some(0.0),
            battery_capacity: None,
            battery_regen_rate: None,
        }
    }

    /// Yamato's real default-hull `floodNodes[0][0]` is 0.15 (GameParams
    /// `PJSB018_Yamato_1944` `A_Hull`); flood_prob = (0.333 - 0.15) / 0.333.
    fn yamato_hull() -> HullComponentStats {
        let flood_prob = (DEFAULT_UW_DAMAGE_COEFF - 0.15) / DEFAULT_UW_DAMAGE_COEFF;
        HullComponentStats { flood_prob: Some(flood_prob), ..Default::default() }
    }

    /// Balao's real submarine battery (GameParams `PASS110_Balao` `A_Hull`
    /// `SubmarineBattery`): capacity 240, regenRate 1.2.
    fn balao_hull() -> HullComponentStats {
        HullComponentStats { battery_capacity: Some(240.0), battery_regen_rate: Some(1.2), ..Default::default() }
    }

    /// Gearing's engine `speedCoef` is 0.0 (hull carries the full coef).
    fn gearing_engine() -> EngineComponentStats {
        EngineComponentStats { speed_coef: Some(0.0) }
    }

    fn modifier(name: &str, value: f32) -> CrewSkillModifier {
        CrewSkillModifier::builder()
            .name(name.to_string())
            .aircraft_carrier(value)
            .auxiliary(value)
            .battleship(value)
            .cruiser(value)
            .destroyer(value)
            .submarine(value)
            .excluded_consumables(Vec::new())
            .build()
    }

    #[test]
    fn gearing_stock_durability_health() {
        let durability = durability(&gearing_hull(), &ModifierBundle::empty(Species::Destroyer), 10);
        // ceil(19400 / 50) * 50 = 19400 (healthPerLevel 0, healthHullCoeff 1).
        assert_eq!(durability.health, Some(Hp::from(19400.0)));
    }

    #[test]
    fn gearing_stock_durability_ptz_zero() {
        // Gearing floodNodes[0][0] == DEFAULT_UW_DAMAGE_COEFF -> flood_prob 0 -> ptz 0.
        let durability = durability(&gearing_hull(), &ModifierBundle::empty(Species::Destroyer), 10);
        assert_eq!(durability.torpedo_protection, Some(Percent::from(0.0)));
    }

    #[test]
    fn yamato_stock_durability_ptz() {
        // flood_prob * 1.0 (stock uwCoeffMultiplier) * 100 + 0 (stock uwCoeffBonus).
        // (0.333 - 0.15) / 0.333 * 100 = 54.9549... (Yamato in-game ptz ~55%).
        let durability = durability(&yamato_hull(), &ModifierBundle::empty(Species::Battleship), 10);
        let ptz = durability.torpedo_protection.expect("ptz computed").value();
        let expected = (DEFAULT_UW_DAMAGE_COEFF - 0.15) / DEFAULT_UW_DAMAGE_COEFF * 100.0;
        assert!((ptz - expected).abs() < 1e-4, "got {ptz}, expected {expected}");
        assert!((ptz - 54.954956).abs() < 1e-3, "got {ptz}");
    }

    #[test]
    fn yamato_ptz_modifier_applies() {
        // uwCoeffBonus +25 (additive) shifts ptz by +25: 54.9549... + 25 = 79.9549...
        let mods = [modifier("uwCoeffBonus", 25.0)];
        let bundle = ModifierBundle::from_modifiers(&mods, Species::Battleship, BUILD);
        let durability = durability(&yamato_hull(), &bundle, 10);
        let ptz = durability.torpedo_protection.expect("ptz computed").value();
        let expected = (DEFAULT_UW_DAMAGE_COEFF - 0.15) / DEFAULT_UW_DAMAGE_COEFF * 100.0 + 25.0;
        assert!((ptz - expected).abs() < 1e-4, "got {ptz}, expected {expected}");
    }

    #[test]
    fn ptz_none_when_flood_absent() {
        // No floodNodes -> flood_prob None -> ptz None (not fabricated).
        let hull = HullComponentStats::default();
        let durability = durability(&hull, &ModifierBundle::empty(Species::Destroyer), 10);
        assert!(durability.torpedo_protection.is_none());
    }

    #[test]
    fn gearing_stock_mobility() {
        let mobility = mobility(&gearing_hull(), &gearing_engine(), &ModifierBundle::empty(Species::Destroyer));
        // 36 * clamp(1.0 + 0.0) * 1.0 = 36.
        assert_eq!(mobility.speed, Some(Knots::from(36.0)));
        // turningRadius is a direct field.
        assert_eq!(mobility.turning_radius, Some(Meters::from(640.0)));
        // 4.25 * 1.0 (stock SGRudderTime) = 4.25.
        assert_eq!(mobility.rudder_time, Some(Seconds::from(4.25)));
    }

    #[test]
    fn speed_coef_modifier_applies() {
        // speedCoef 1.05 -> 36 * 1.0 * 1.05 = 37.8.
        let mods = [modifier("speedCoef", 1.05)];
        let bundle = ModifierBundle::from_modifiers(&mods, Species::Destroyer, BUILD);
        let mobility = mobility(&gearing_hull(), &gearing_engine(), &bundle);
        let speed = mobility.speed.expect("speed computed").value();
        assert!((speed - 37.8).abs() < 1e-4, "got {speed}");
    }

    #[test]
    fn health_modifier_applies() {
        // healthPerLevel 350 (bonus, +) and healthHullCoeff 1.05 (coef, *):
        // (19400 + 350*10) * 1.05 = 22900*1.05 = 24045 -> ceil(24045/50)*50 = 24050.
        let mods = [modifier("healthPerLevel", 350.0), modifier("healthHullCoeff", 1.05)];
        let bundle = ModifierBundle::from_modifiers(&mods, Species::Destroyer, BUILD);
        let durability = durability(&gearing_hull(), &bundle, 10);
        assert_eq!(durability.health, Some(Hp::from(24050.0)));
    }

    #[test]
    fn absent_inputs_are_none() {
        let empty_hull = HullComponentStats::default();
        let durability = durability(&empty_hull, &ModifierBundle::empty(Species::Destroyer), 10);
        assert!(durability.health.is_none());

        let mobility =
            mobility(&empty_hull, &EngineComponentStats::default(), &ModifierBundle::empty(Species::Destroyer));
        assert!(mobility.speed.is_none());
        assert!(mobility.turning_radius.is_none());
        assert!(mobility.rudder_time.is_none());

        // No SubmarineBattery -> battery None.
        assert!(battery(&empty_hull, &ModifierBundle::empty(Species::Submarine)).is_none());
    }

    #[test]
    fn balao_stock_battery() {
        // capacity 240 * 1.0, regenRate 1.2 * 1.0 (stock battery coeffs).
        let battery = battery(&balao_hull(), &ModifierBundle::empty(Species::Submarine)).expect("battery computed");
        assert_eq!(battery.capacity, Some(240.0));
        assert_eq!(battery.regeneration, Some(1.2));
    }

    #[test]
    fn balao_battery_modifiers_apply() {
        // batteryCapacityCoeff 1.1 (coef) -> 240*1.1=264; batteryRegenCoeff 1.25 -> 1.2*1.25=1.5.
        let mods = [modifier("batteryCapacityCoeff", 1.1), modifier("batteryRegenCoeff", 1.25)];
        let bundle = ModifierBundle::from_modifiers(&mods, Species::Submarine, BUILD);
        let battery = battery(&balao_hull(), &bundle).expect("battery computed");
        let capacity = battery.capacity.expect("capacity");
        let regen = battery.regeneration.expect("regen");
        assert!((capacity - 264.0).abs() < 1e-4, "got {capacity}");
        assert!((regen - 1.5).abs() < 1e-4, "got {regen}");
    }

    #[test]
    fn battery_none_for_non_sub() {
        // Gearing has no SubmarineBattery -> battery None.
        assert!(battery(&gearing_hull(), &ModifierBundle::empty(Species::Destroyer)).is_none());
    }

    /// Build an [`ArmorMap`] from `(raw_key, thickness)` pairs, mirroring
    /// `parse_armor_dict`'s `(model_index << 16) | material_id` keying.
    fn armor_map(entries: &[(u32, f32)]) -> ArmorMap {
        use std::collections::BTreeMap;
        let mut m: ArmorMap = std::collections::HashMap::new();
        for &(raw, thk) in entries {
            let model_index = raw >> 16;
            let material_id = raw & 0xFFFF;
            m.entry(material_id).or_default().insert(model_index, thk);
        }
        m
    }

    /// Subset of Yamato's `PJSB018_Yamato_1944 A_Hull.armor`: a Cit_Belt plate
    /// (mat 61, 410mm), a Tur1GkBar barbette (mat 134, 560mm), an unclassified
    /// RudderSide plate (mat 82, 350mm, must be excluded), and a thin SS_Side
    /// (mat 89, 19mm). Raw keys use model_index 2 (131072) like the real data.
    fn yamato_hull_armor() -> ArmorMap {
        armor_map(&[
            (131072 | 61, 410.0),  // Cit_Belt
            (131072 | 134, 560.0), // Tur1GkBar (barbette, classifies as ARTI)
            (131072 | 82, 350.0),  // RudderSide (NOT an armor type -> excluded)
            (131072 | 89, 19.0),   // SS_Side
            (1, 0.0),              // common, thickness 0 -> excluded
        ])
    }

    /// Yamato's `A_Artillery.HP_JGM_*.armor`: TurretFwd (mat 100, 650mm face),
    /// TurretSide (mat 32, 250mm), TurretDown (mat 99, 135mm). Gun bits live in
    /// the high byte (model_index 1 here); only the low byte selects the material.
    fn yamato_turret_armor() -> ArmorMap {
        armor_map(&[
            (65536 | 100, 650.0), // TurretFwd (turret face)
            (65536 | 32, 250.0),  // TurretSide
            (65536 | 99, 135.0),  // TurretDown
        ])
    }

    #[test]
    fn yamato_armor_min_max_with_artillery() {
        // hull classified: {410, 560, 19}; arti classified: {650, 250, 135}.
        // max = max(650, 560) = 650 (Yamato's in-game turret armor).
        // min = min(135, 19)  = 19.
        let hull = yamato_hull_armor();
        let arti = [yamato_turret_armor()];
        let armor = armor(&hull, arti.iter()).expect("armor computed");
        assert_eq!(armor.max, Some(Millimeters::from(650.0)));
        assert_eq!(armor.min, Some(Millimeters::from(19.0)));
    }

    #[test]
    fn hull_only_armor_excludes_unclassified() {
        // No artillery branch: extremes over classified hull plates only.
        // RudderSide (350) is excluded, so max = 560 (Tur1GkBar), min = 19.
        let hull = yamato_hull_armor();
        let armor = armor(&hull, std::iter::empty()).expect("armor computed");
        assert_eq!(armor.max, Some(Millimeters::from(560.0)));
        assert_eq!(armor.min, Some(Millimeters::from(19.0)));
    }

    #[test]
    fn armor_none_when_hull_armor_absent() {
        // No armor data at all -> None (not fabricated as the default 6mm).
        let empty: ArmorMap = std::collections::HashMap::new();
        assert!(armor(&empty, std::iter::empty()).is_none());
    }

    #[test]
    fn armor_defaults_when_no_classified_plate() {
        // Hull with only unclassified plates -> default 6mm extremes
        // (PreprocessedArmor.py:8 seed), not None: the hull map is non-empty.
        let hull = armor_map(&[(131072 | 82, 350.0), (131072 | 80, 200.0)]); // Rudder*
        let armor = armor(&hull, std::iter::empty()).expect("armor computed");
        assert_eq!(armor.min, Some(Millimeters::from(6.0)));
        assert_eq!(armor.max, Some(Millimeters::from(6.0)));
    }

    use crate::Rc;
    use crate::game_params::types::Param;
    use crate::game_params::types::ParamData;
    use crate::game_types::GameParamId;

    /// Gearing's real `PAPT027_Mk_16_mod_1` torpedo (GameParams Projectile):
    /// ammoType "torpedo", torpedoType COMMON(0), maxDist 350 (BW), speed 66,
    /// alphaDamage 53500, damage (flood) 1200, visibilityFactor 1.4.
    fn gearing_torpedo() -> Projectile {
        Projectile::builder()
            .ammo_type("torpedo".to_string())
            .max_dist(crate::game_params::types::BigWorldDistance::from(350.0))
            .speed(66.0)
            .alpha_damage(53500.0)
            .damage(1200.0)
            .visibility_factor(1.4)
            .torpedo_type(0)
            .build()
    }

    /// Gearing's real torpedo launcher mount (`HP_AGT_*`): shotDelay 103,
    /// rotationSpeed[0] 25, numBarrels 5, one ammo PAPT027_Mk_16_mod_1.
    fn gearing_launcher() -> TorpedoLauncherStats {
        TorpedoLauncherStats {
            shot_delay: Some(Seconds::from(103.0)),
            rotation_speed: Some(DegreesPerSecond::from(25.0)),
            num_barrels: Some(5.0),
            ammo_switch_coeff: None,
            ammo: vec!["PAPT027_Mk_16_mod_1".to_string()],
        }
    }

    /// A minimal in-memory provider exposing one named Projectile param, enough to
    /// exercise the name->projectile resolver in `torpedoes` without a full
    /// GameParams index.
    struct StubProvider {
        param: Rc<Param>,
    }

    impl StubProvider {
        fn new(name: &str, projectile: Projectile) -> Self {
            let param = Param::builder()
                .id(GameParamId::from(1u32))
                .index("S0001".to_string())
                .name(name.to_string())
                .nation("USA".to_string())
                .data(ParamData::Projectile(projectile))
                .build();
            StubProvider { param: Rc::new(param) }
        }
    }

    impl GameParamProvider for StubProvider {
        fn game_param_by_id(&self, _id: GameParamId) -> Option<Rc<Param>> {
            None
        }
        fn game_param_by_index(&self, _index: &str) -> Option<Rc<Param>> {
            None
        }
        fn game_param_by_name(&self, name: &str) -> Option<Rc<Param>> {
            (self.param.name() == name).then(|| self.param.clone())
        }
        fn params(&self) -> &[Rc<Param>] {
            std::slice::from_ref(&self.param)
        }
    }

    fn approx(a: f32, b: f32) -> bool {
        (a - b).abs() < 1e-2
    }

    #[test]
    fn gearing_stock_torpedo_stats() {
        let stats = torpedo_stats(
            "PAPT027_Mk_16_mod_1".to_string(),
            &gearing_torpedo(),
            &ModifierBundle::empty(Species::Destroyer),
        );
        // damage: 53500/3 + 1200 = 19033.33 (alphaDamage/3 + flood, stock coeffs 1.0).
        let damage = stats.damage.expect("damage").value();
        assert!(approx(damage, 53500.0 / 3.0 + 1200.0), "got {damage}");
        // speed: 66 * 1.0 * 1.0 + 0 = 66.
        assert_eq!(stats.speed, Some(Knots::from(66.0)));
        // range: 350 * 1.0 * 30 / 1000 = 10.5.
        let range = stats.range.expect("range").value();
        assert!(approx(range, 10.5), "got {range}");
        // visibility: 1.4 * 1.0 = 1.4.
        assert_eq!(stats.visibility, Some(Km::from(1.4)));
        // No distanceOfDamage on Gearing's torpedo -> is_damage_increasing None.
        assert!(stats.is_damage_increasing.is_none());
        // distanceOfMaxDamage needs armingTime/maneuverDist (absent) -> None.
        assert!(stats.distance_of_max_damage.is_none());
        // Surface path -> disabledUnderwater not set.
        assert!(stats.disabled_underwater.is_none());
    }

    #[test]
    fn gearing_stock_torpedoes_via_provider() {
        let launchers = [gearing_launcher()];
        let provider = StubProvider::new("PAPT027_Mk_16_mod_1", gearing_torpedo());
        let torps =
            torpedoes(&launchers, &ModifierBundle::empty(Species::Destroyer), &provider).expect("torpedoes computed");

        // reload_time: shotDelay 103 * GTShotDelay 1.0 = 103 (min over one mount).
        assert_eq!(torps.reload_time, Some(Seconds::from(103.0)));

        // launcher: rotationSpeed 25 * 1.0 + 0 = 25; rotation_time = 180/25 = 7.2.
        assert_eq!(torps.launchers.len(), 1);
        let launcher = &torps.launchers[0];
        assert_eq!(launcher.rotation_speed, Some(DegreesPerSecond::from(25.0)));
        let rt = launcher.rotation_time.expect("rotation_time").value();
        assert!(approx(rt, 7.2), "got {rt}");
        assert_eq!(launcher.num_barrels, Some(5));

        // per-ammo resolved by name.
        assert_eq!(torps.torpedoes.len(), 1);
        let torp = &torps.torpedoes[0];
        assert_eq!(torp.name, "PAPT027_Mk_16_mod_1");
        assert!(approx(torp.damage.expect("damage").value(), 53500.0 / 3.0 + 1200.0));
        assert_eq!(torp.speed, Some(Knots::from(66.0)));
        assert!(approx(torp.range.expect("range").value(), 10.5));
        assert_eq!(torp.visibility, Some(Km::from(1.4)));
    }

    #[test]
    fn torpedo_speed_bonus_applies() {
        // torpedoSpeedBonus +5 (additive): 66 + 5 = 71.
        let mods = [modifier("torpedoSpeedBonus", 5.0)];
        let bundle = ModifierBundle::from_modifiers(&mods, Species::Destroyer, BUILD);
        let stats = torpedo_stats("PAPT027_Mk_16_mod_1".to_string(), &gearing_torpedo(), &bundle);
        let speed = stats.speed.expect("speed").value();
        assert!(approx(speed, 71.0), "got {speed}");
    }

    #[test]
    fn torpedo_damage_coeff_applies() {
        // torpedoDamageCoeff 1.2 (coef): (53500/3 + 1200) * 1.2.
        let mods = [modifier("torpedoDamageCoeff", 1.2)];
        let bundle = ModifierBundle::from_modifiers(&mods, Species::Destroyer, BUILD);
        let stats = torpedo_stats("PAPT027_Mk_16_mod_1".to_string(), &gearing_torpedo(), &bundle);
        let damage = stats.damage.expect("damage").value();
        assert!(approx(damage, (53500.0 / 3.0 + 1200.0) * 1.2), "got {damage}");
    }

    #[test]
    fn torpedo_launcher_traverse_coef_applies() {
        // GTRotationSpeed 1.2 (Torpedo_Mod_II, +20% traverse), real modifier name
        // mapped from GunRotationSpeedModifiersStruct.yawSpeedCoef
        // (GunRotationSpeed.py:10-13, ModifiersApply.py:123). base 25 -> 30, time 180/30 = 6.
        let mods = [modifier("GTRotationSpeed", 1.2)];
        let bundle = ModifierBundle::from_modifiers(&mods, Species::Destroyer, BUILD);
        let launchers = [gearing_launcher()];
        let provider = StubProvider::new("PAPT027_Mk_16_mod_1", gearing_torpedo());
        let torps = torpedoes(&launchers, &bundle, &provider).expect("torpedoes computed");
        let launcher = &torps.launchers[0];
        let rs = launcher.rotation_speed.expect("rotation_speed").value();
        assert!(approx(rs, 30.0), "got {rs}");
        let rt = launcher.rotation_time.expect("rotation_time").value();
        assert!(approx(rt, 6.0), "got {rt}");
    }

    #[test]
    fn torpedo_launcher_traverse_bonus_applies() {
        // GTRotationSpeedBonus +5 (additive, base 0.0): 25 + 5 = 30, time 180/30 = 6.
        let mods = [modifier("GTRotationSpeedBonus", 5.0)];
        let bundle = ModifierBundle::from_modifiers(&mods, Species::Destroyer, BUILD);
        let launchers = [gearing_launcher()];
        let provider = StubProvider::new("PAPT027_Mk_16_mod_1", gearing_torpedo());
        let torps = torpedoes(&launchers, &bundle, &provider).expect("torpedoes computed");
        let launcher = &torps.launchers[0];
        assert_eq!(launcher.rotation_speed, Some(DegreesPerSecond::from(30.0)));
        let rt = launcher.rotation_time.expect("rotation_time").value();
        assert!(approx(rt, 6.0), "got {rt}");
    }

    #[test]
    fn torpedoes_none_when_no_launchers() {
        let provider = StubProvider::new("PAPT027_Mk_16_mod_1", gearing_torpedo());
        assert!(torpedoes(&[], &ModifierBundle::empty(Species::Destroyer), &provider).is_none());
    }

    #[test]
    fn torpedo_stats_none_when_inputs_absent() {
        // A projectile with no torpedo fields -> all stats None (no fabrication).
        let empty = Projectile::builder().ammo_type("torpedo".to_string()).build();
        let stats = torpedo_stats("X".to_string(), &empty, &ModifierBundle::empty(Species::Destroyer));
        assert!(stats.damage.is_none());
        assert!(stats.speed.is_none());
        assert!(stats.range.is_none());
        assert!(stats.visibility.is_none());
    }

    /// Worcester's real HE shell `PAPA051_152mm_HE_HC_Mark_39_Mod_0` (GameParams):
    /// ammoType "HE", alphaDamage 2200, alphaPiercingHE 30, burnProb 0.12,
    /// uwCritical 0.0, bulletDiametr 0.152, bulletSpeed 812, timeFactor 1.0.
    fn worcester_he() -> Projectile {
        Projectile::builder()
            .ammo_type("HE".to_string())
            .alpha_damage(2200.0)
            .alpha_piercing_he(30.0)
            .burn_prob(0.12)
            .uw_critical(0.0)
            .bullet_diametr(0.152)
            .bullet_speed(812.0)
            .build()
    }

    /// Worcester's real AP shell `PAPA050_152mm_AP_130lbs_Mk35` (GameParams):
    /// ammoType "AP", alphaDamage 3200, burnProb -0.5 (N/A), uwCritical 0.0,
    /// bulletDiametr 0.152, bulletSpeed 762, timeFactor 1.0.
    fn worcester_ap() -> Projectile {
        Projectile::builder()
            .ammo_type("AP".to_string())
            .alpha_damage(3200.0)
            .burn_prob(-0.5)
            .uw_critical(0.0)
            .bullet_diametr(0.152)
            .bullet_speed(762.0)
            .build()
    }

    /// Worcester's real `ArtilleryDefault` component + `HP_AGM_*` gun fields
    /// (GameParams `PASC016_Worcester_1948`): maxDist 15320 (BW), 6 guns, each
    /// barrelDiameter 0.152, shotDelay 4.6, rotationSpeed[0] 25, numBarrels 2,
    /// ammoSwitchCoeff 1.0, minRadius 1.1, idealRadius 8, idealDistance 1000, ammo HE+AP.
    fn worcester_artillery() -> ArtilleryComponentStats {
        let gun = || ArtilleryGunStats {
            shot_delay: Some(Seconds::from(4.6)),
            rotation_speed: Some(DegreesPerSecond::from(25.0)),
            num_barrels: Some(2.0),
            barrel_diameter: Some(Meters::from(0.152)),
            ammo_switch_coeff: Some(1.0),
            min_radius: Some(1.1),
            ideal_radius: Some(8.0),
            ideal_distance: Some(1000.0),
            ammo: vec!["PAPA051_152mm_HE_HC_Mark_39_Mod_0".to_string(), "PAPA050_152mm_AP_130lbs_Mk35".to_string()],
        };
        ArtilleryComponentStats {
            max_dist: Some(Meters::from(15320.0)),
            guns: vec![gun(), gun(), gun(), gun(), gun(), gun()],
        }
    }

    /// A multi-param provider exposing both Worcester shells by name.
    struct MultiProvider {
        params: Vec<Rc<Param>>,
    }

    impl MultiProvider {
        fn new(entries: &[(&str, Projectile)]) -> Self {
            let params = entries
                .iter()
                .enumerate()
                .map(|(i, (name, proj))| {
                    Rc::new(
                        Param::builder()
                            .id(GameParamId::from((i + 1) as u32))
                            .index(format!("S{i:04}"))
                            .name(name.to_string())
                            .nation("USA".to_string())
                            .data(ParamData::Projectile(proj.clone()))
                            .build(),
                    )
                })
                .collect();
            MultiProvider { params }
        }
    }

    impl GameParamProvider for MultiProvider {
        fn game_param_by_id(&self, _id: GameParamId) -> Option<Rc<Param>> {
            None
        }
        fn game_param_by_index(&self, _index: &str) -> Option<Rc<Param>> {
            None
        }
        fn game_param_by_name(&self, name: &str) -> Option<Rc<Param>> {
            self.params.iter().find(|p| p.name() == name).cloned()
        }
        fn params(&self) -> &[Rc<Param>] {
            &self.params
        }
    }

    fn worcester_provider() -> MultiProvider {
        MultiProvider::new(&[
            ("PAPA051_152mm_HE_HC_Mark_39_Mod_0", worcester_he()),
            ("PAPA050_152mm_AP_130lbs_Mk35", worcester_ap()),
        ])
    }

    #[test]
    fn worcester_stock_artillery_gun_and_range() {
        let provider = worcester_provider();
        let arty = artillery(&worcester_artillery(), &ModifierBundle::empty(Species::Cruiser), 1.0, 10, &provider)
            .expect("artillery computed");

        // range: (15320 / 1000) * 1.0 (fc) * 1.0 (GMMaxDist) = 15.32.
        assert_eq!(arty.range, Some(Km::from(15.32)));
        // reload: 4.6 * 1.0 (GMShotDelay) = 4.6.
        assert_eq!(arty.reload_time, Some(Seconds::from(4.6)));
        // ammoSwitchTime: 4.6 * 1.0 * 1.0 * 1.0 = 4.6.
        let st = arty.ammo_switch_time.expect("switch time").value();
        assert!(approx(st, 4.6), "got {st}");

        let gun = arty.gun.expect("gun");
        // caliber: 0.152 * 1000 = 152.
        assert_eq!(gun.caliber, Some(Millimeters::from(152.0)));
        assert_eq!(gun.num_guns, Some(6));
        assert_eq!(gun.num_barrels, Some(2));
        // rotation: 25 * 1.0 + 0 = 25; time 180/25 = 7.2.
        assert_eq!(gun.rotation_speed, Some(DegreesPerSecond::from(25.0)));
        let rt = gun.rotation_time.expect("rotation_time").value();
        assert!(approx(rt, 7.2), "got {rt}");
    }

    #[test]
    fn worcester_stock_dispersion_matches_helper() {
        let provider = worcester_provider();
        let arty = artillery(&worcester_artillery(), &ModifierBundle::empty(Species::Cruiser), 1.0, 10, &provider)
            .expect("artillery computed");
        // dispersion over the FC-adjusted range 15.32 km, stock GMIdealRadius 1.0.
        let expected = constants::dispersion(1.1, 8.0, 1000.0, 15.32, 1.0);
        let got = arty.dispersion.expect("dispersion").value();
        assert!((got - expected).abs() < 1e-3, "got {got} expected {expected}");
        // The transcribed formula yields ~138.7 m at 15.32 km for Worcester's gun
        // (minRadius 1.1 / idealRadius 8 / idealDistance 1000); same BW_TO_SHIP=15
        // scale that recovers NC's 271 m and Yamato's 273 m in constants.rs.
        assert!((got - 138.7).abs() < 1.0, "got {got}");
    }

    #[test]
    fn worcester_stock_he_shell() {
        let provider = worcester_provider();
        let arty = artillery(&worcester_artillery(), &ModifierBundle::empty(Species::Cruiser), 1.0, 10, &provider)
            .expect("artillery computed");
        let he = arty.shells.iter().find(|s| s.ammo_kind.as_deref() == Some("HE")).expect("HE shell");
        // stock damage reduces to alphaDamage 2200.
        assert_eq!(he.damage, Some(Hp::from(2200.0)));
        // penetration: floor(30 * 1.0) = 30.
        assert_eq!(he.penetration, Some(Millimeters::from(30.0)));
        // burnChance: 0.12 * 100 = 12%.
        assert_eq!(he.burn_chance, Some(Percent::from(12.0)));
        assert_eq!(he.caliber, Some(Millimeters::from(152.0)));
        // speed: 812 * 1.0 (timeFactor) = 812.
        assert_eq!(he.speed, Some(812.0));
        // floodChance: uwCritical 0.0 * 100 = 0.
        assert_eq!(he.flood_chance, Some(Percent::from(0.0)));
        // Main battery -> unlimited pool.
        assert_eq!(he.max_ammo, Some(AmmoCount::Infinite));
    }

    #[test]
    fn worcester_stock_ap_shell() {
        let provider = worcester_provider();
        let arty = artillery(&worcester_artillery(), &ModifierBundle::empty(Species::Cruiser), 1.0, 10, &provider)
            .expect("artillery computed");
        let ap = arty.shells.iter().find(|s| s.ammo_kind.as_deref() == Some("AP")).expect("AP shell");
        // stock damage reduces to alphaDamage 3200.
        assert_eq!(ap.damage, Some(Hp::from(3200.0)));
        // AP penetration is a ballistic sim -> None (deferred).
        assert!(ap.penetration.is_none());
        // AP burnProb -0.5 (N/A) -> calculate_burn_chance clamps to 0%.
        assert_eq!(ap.burn_chance, Some(Percent::from(0.0)));
        // AP has no floodChance.
        assert!(ap.flood_chance.is_none());
        // speed: 762 * 1.0 = 762.
        assert_eq!(ap.speed, Some(762.0));
    }

    #[test]
    fn worcester_modified_reload_and_range() {
        // GMShotDelay 0.9 -> reload 4.6 * 0.9 = 4.14; GMMaxDist 1.1 -> range 15.32 * 1.1 = 16.852.
        let mods = [modifier("GMShotDelay", 0.9), modifier("GMMaxDist", 1.1)];
        let bundle = ModifierBundle::from_modifiers(&mods, Species::Cruiser, BUILD);
        let provider = worcester_provider();
        let arty = artillery(&worcester_artillery(), &bundle, 1.0, 10, &provider).expect("artillery computed");
        let reload = arty.reload_time.expect("reload").value();
        assert!(approx(reload, 4.14), "got {reload}");
        let range = arty.range.expect("range").value();
        assert!(approx(range, 16.852), "got {range}");
    }

    #[test]
    fn worcester_traverse_modifier_applies() {
        // GMRotationSpeed 1.2 (+20% traverse): 25 -> 30, rotation_time 180/30 = 6.
        let mods = [modifier("GMRotationSpeed", 1.2)];
        let bundle = ModifierBundle::from_modifiers(&mods, Species::Cruiser, BUILD);
        let provider = worcester_provider();
        let arty = artillery(&worcester_artillery(), &bundle, 1.0, 10, &provider).expect("artillery computed");
        let gun = arty.gun.expect("gun");
        let rs = gun.rotation_speed.expect("rotation_speed").value();
        assert!(approx(rs, 30.0), "got {rs}");
        let rt = gun.rotation_time.expect("rotation_time").value();
        assert!(approx(rt, 6.0), "got {rt}");
    }

    #[test]
    fn artillery_none_when_no_guns() {
        let provider = worcester_provider();
        let empty = ArtilleryComponentStats::default();
        assert!(artillery(&empty, &ModifierBundle::empty(Species::Cruiser), 1.0, 10, &provider).is_none());
    }

    #[test]
    fn artillery_drops_unresolvable_ammo_row() {
        // Provider knows only the HE shell; the AP ammo name does not resolve. The
        // section is still produced with the resolvable HE row, and the AP row is
        // silently dropped (a warn-once diagnostic fires; no fabrication).
        let provider = MultiProvider::new(&[("PAPA051_152mm_HE_HC_Mark_39_Mod_0", worcester_he())]);
        let arty = artillery(&worcester_artillery(), &ModifierBundle::empty(Species::Cruiser), 1.0, 10, &provider)
            .expect("artillery computed");
        assert_eq!(arty.shells.len(), 1);
        assert!(arty.shells.iter().any(|s| s.ammo_kind.as_deref() == Some("HE")));
        assert!(!arty.shells.iter().any(|s| s.ammo_kind.as_deref() == Some("AP")));
    }

    #[test]
    fn shell_stats_none_when_inputs_absent() {
        // A projectile with no shell fields -> stat fields None (no fabrication).
        let empty = Projectile::builder().ammo_type("HE".to_string()).build();
        let stats = shell_stats("X".to_string(), &empty, &ModifierBundle::empty(Species::Cruiser), 10, false);
        assert!(stats.damage.is_none());
        assert!(stats.caliber.is_none());
        assert!(stats.speed.is_none());
        assert!(stats.penetration.is_none());
        assert!(stats.burn_chance.is_none());
        assert!(stats.flood_chance.is_none());
    }

    #[test]
    fn shell_speed_applies_time_factor() {
        // PXPA005_305MM_HE_RASPUTIN (GameParams): timeFactor 0.5, bulletSpeed 762 ->
        // displayed speed 762 * 0.5 = 381 (PreprocessedAmmo.py:16).
        let shell = Projectile::builder()
            .ammo_type("HE".to_string())
            .bullet_diametr(0.305)
            .bullet_speed(762.0)
            .time_factor(0.5)
            .build();
        let stats = shell_stats("X".to_string(), &shell, &ModifierBundle::empty(Species::Cruiser), 10, false);
        assert_eq!(stats.speed, Some(381.0));

        // A shell without timeFactor defaults to 1.0 (maa3520d6.py:1151): speed == bulletSpeed.
        let plain = Projectile::builder().ammo_type("HE".to_string()).bullet_diametr(0.152).bullet_speed(812.0).build();
        let plain_stats = shell_stats("Y".to_string(), &plain, &ModifierBundle::empty(Species::Cruiser), 10, false);
        assert_eq!(plain_stats.speed, Some(812.0));
    }

    use crate::game_params::ttx::components::SecondaryComponentStats;

    /// Bismarck's real 150mm secondary shell `PGPA003_150mm_HE_HE_N_F` (GameParams
    /// `PGSB108_Bismarck`): ammoType "HE", alphaDamage 1700, alphaPiercingHE 38,
    /// burnProb 0.08, bulletDiametr 0.15, bulletSpeed 875, uwCritical 0.0.
    fn bismarck_150mm_he() -> Projectile {
        Projectile::builder()
            .ammo_type("HE".to_string())
            .alpha_damage(1700.0)
            .alpha_piercing_he(38.0)
            .burn_prob(0.08)
            .uw_critical(0.0)
            .bullet_diametr(0.15)
            .bullet_speed(875.0)
            .build()
    }

    /// Bismarck's real 105mm secondary shell `PGPA085_105mm_HE_HE_33lbs`: ammoType "HE",
    /// alphaDamage 1200, alphaPiercingHE 26, burnProb 0.05, bulletDiametr 0.105,
    /// bulletSpeed 900, uwCritical 0.0.
    fn bismarck_105mm_he() -> Projectile {
        Projectile::builder()
            .ammo_type("HE".to_string())
            .alpha_damage(1200.0)
            .alpha_piercing_he(26.0)
            .burn_prob(0.05)
            .uw_critical(0.0)
            .bullet_diametr(0.105)
            .bullet_speed(900.0)
            .build()
    }

    /// Bismarck's `A_ATBA` component + `HP_GGS_*` mixed-caliber guns (GameParams
    /// `PGSB108_Bismarck`): component maxDist 7600 (BigWorld, == 7.6 km in-game range).
    /// The 150mm group (PGGS001) shotDelay 7.5, barrelDiameter 0.15, numBarrels 2,
    /// rotationSpeed[0] 60, minRadius 1.0, idealRadius 15.5, idealDistance 333.333; the
    /// 105mm group (PGGS003) shotDelay 3.35, barrelDiameter 0.105. The first gun group
    /// (150mm) drives the displayed reload/gun.
    fn bismarck_secondaries() -> SecondaryComponentStats {
        let gun_150 = ArtilleryGunStats {
            shot_delay: Some(Seconds::from(7.5)),
            rotation_speed: Some(DegreesPerSecond::from(60.0)),
            num_barrels: Some(2.0),
            barrel_diameter: Some(Meters::from(0.15)),
            ammo_switch_coeff: None,
            min_radius: Some(1.0),
            ideal_radius: Some(15.5),
            ideal_distance: Some(333.333),
            ammo: vec!["PGPA003_150mm_HE_HE_N_F".to_string()],
        };
        let gun_105 = ArtilleryGunStats {
            shot_delay: Some(Seconds::from(3.35)),
            rotation_speed: Some(DegreesPerSecond::from(60.0)),
            num_barrels: Some(2.0),
            barrel_diameter: Some(Meters::from(0.105)),
            ammo_switch_coeff: None,
            min_radius: Some(1.0),
            ideal_radius: Some(15.5),
            ideal_distance: Some(333.333),
            ammo: vec!["PGPA085_105mm_HE_HE_33lbs".to_string()],
        };
        SecondaryComponentStats {
            max_dist: Some(Meters::from(7600.0)),
            // 14 mounts total: 6 x 150mm groups + 8 x 105mm groups (calibers as 2 distinct ammo).
            guns: vec![gun_150.clone(), gun_150, gun_105.clone(), gun_105],
        }
    }

    fn bismarck_secondary_provider() -> MultiProvider {
        MultiProvider::new(&[
            ("PGPA003_150mm_HE_HE_N_F", bismarck_150mm_he()),
            ("PGPA085_105mm_HE_HE_33lbs", bismarck_105mm_he()),
        ])
    }

    #[test]
    fn bismarck_stock_secondaries_gun_and_range() {
        let provider = bismarck_secondary_provider();
        let sec = secondaries(&bismarck_secondaries(), &ModifierBundle::empty(Species::Battleship), 8, &provider)
            .expect("secondaries computed");

        // range: (7600 / 1000) * 1.0 (GSMaxDist) = 7.6 (Bismarck's in-game stock range).
        assert_eq!(sec.range, Some(Km::from(7.6)));
        // reload: 7.5 * 1.0 (GSShotDelay) = 7.5 (first gun group, the 150mm mount).
        assert_eq!(sec.reload_time, Some(Seconds::from(7.5)));
        // secondaries have no ammo-switch time.
        assert!(sec.ammo_switch_time.is_none());

        let gun = sec.gun.expect("gun");
        // caliber: 0.15 * 1000 = 150 (first gun group).
        assert_eq!(gun.caliber, Some(Millimeters::from(150.0)));
        // num_guns counts all mounts (mixed calibers).
        assert_eq!(gun.num_guns, Some(4));
        assert_eq!(gun.num_barrels, Some(2));
        // rotation: 60 * 1.0 + 0 = 60; time 180/60 = 3.
        assert_eq!(gun.rotation_speed, Some(DegreesPerSecond::from(60.0)));
        let rt = gun.rotation_time.expect("rotation_time").value();
        assert!(approx(rt, 3.0), "got {rt}");
    }

    #[test]
    fn bismarck_stock_secondaries_shells() {
        let provider = bismarck_secondary_provider();
        let sec = secondaries(&bismarck_secondaries(), &ModifierBundle::empty(Species::Battleship), 8, &provider)
            .expect("secondaries computed");

        // One shell per distinct ATBA ammo across the mixed-caliber mounts.
        assert_eq!(sec.shells.len(), 2);

        let s150 = sec.shells.iter().find(|s| s.name == "PGPA003_150mm_HE_HE_N_F").expect("150mm shell");
        // stock ATBA damage reduces to alphaDamage 1700 (GS coeffs all 1.0).
        assert_eq!(s150.damage, Some(Hp::from(1700.0)));
        // HE penetration: floor(38 * 1.0) = 38 (GSPenetrationCoeffHE stock 1.0).
        assert_eq!(s150.penetration, Some(Millimeters::from(38.0)));
        // burnChance: 0.08 * 100 = 8%.
        assert_eq!(s150.burn_chance, Some(Percent::from(8.0)));
        assert_eq!(s150.caliber, Some(Millimeters::from(150.0)));
        assert_eq!(s150.speed, Some(875.0));
        assert_eq!(s150.flood_chance, Some(Percent::from(0.0)));

        let s105 = sec.shells.iter().find(|s| s.name == "PGPA085_105mm_HE_HE_33lbs").expect("105mm shell");
        assert_eq!(s105.damage, Some(Hp::from(1200.0)));
        assert_eq!(s105.penetration, Some(Millimeters::from(26.0)));
        assert_eq!(s105.burn_chance, Some(Percent::from(5.0)));
        assert_eq!(s105.caliber, Some(Millimeters::from(105.0)));
    }

    #[test]
    fn bismarck_secondary_range_modifier_applies() {
        // GSMaxDist 1.2 (secondary-range upgrade/AtbaRange): 7.6 * 1.2 = 9.12.
        let mods = [modifier("GSMaxDist", 1.2)];
        let bundle = ModifierBundle::from_modifiers(&mods, Species::Battleship, BUILD);
        let provider = bismarck_secondary_provider();
        let sec = secondaries(&bismarck_secondaries(), &bundle, 8, &provider).expect("secondaries computed");
        let range = sec.range.expect("range").value();
        assert!(approx(range, 9.12), "got {range}");
    }

    #[test]
    fn bismarck_secondary_reload_modifier_applies() {
        // GSShotDelay 0.85 (secondary reload upgrade): 7.5 * 0.85 = 6.375.
        let mods = [modifier("GSShotDelay", 0.85)];
        let bundle = ModifierBundle::from_modifiers(&mods, Species::Battleship, BUILD);
        let provider = bismarck_secondary_provider();
        let sec = secondaries(&bismarck_secondaries(), &bundle, 8, &provider).expect("secondaries computed");
        let reload = sec.reload_time.expect("reload").value();
        assert!(approx(reload, 6.375), "got {reload}");
    }

    #[test]
    fn secondaries_none_when_no_guns() {
        let provider = bismarck_secondary_provider();
        let empty = SecondaryComponentStats::default();
        assert!(secondaries(&empty, &ModifierBundle::empty(Species::Battleship), 8, &provider).is_none());
    }

    #[test]
    fn gearing_stock_visibility() {
        // Gearing hull: visibilityFactor 7.33, visibilityFactorByPlane 3.41,
        // visibilityCoefFire 2.0, visibilityCoefFireByPlane 2.0, visibilityCoefGKInSmoke 2.83.
        // Stock = empty bundle, no big-gun penalty, no secondary range.
        let vis = visibility(&gearing_hull(), &ModifierBundle::empty(Species::Destroyer), false, None, None);
        // sea = 7.33 * 1.0 * 1.0 = 7.33.
        assert_eq!(vis.sea_detection, Some(Km::from(7.33)));
        // sea on fire = 7.33 + 2.0 = 9.33.
        let on_fire = vis.sea_detection_on_fire.expect("sea on fire").value();
        assert!(approx(on_fire, 9.33), "got {on_fire}");
        // air = 3.41 * 1.0 * 1.0 = 3.41.
        assert_eq!(vis.air_detection, Some(Km::from(3.41)));
        // air on fire = 3.41 + 2.0 = 5.41.
        let air_fire = vis.air_detection_on_fire.expect("air on fire").value();
        assert!(approx(air_fire, 5.41), "got {air_fire}");
        // smoke = visibilityCoefGKInSmoke 2.83 (> MINIMAL_VALID_VALUE).
        assert_eq!(vis.detection_in_smoke, Some(Km::from(2.83)));
        // No secondary range supplied, DD has no periscope.
        assert!(vis.secondary_range_detection.is_none());
        assert!(vis.periscope_depth_detection.is_none());
    }

    #[test]
    fn concealment_modifier_reduces_sea_detection() {
        // Concealment System Mod 1: visibilityFactor 0.9 (-10%) -> 7.33 * 0.9 = 6.597.
        let mods = [modifier("visibilityFactor", 0.9)];
        let bundle = ModifierBundle::from_modifiers(&mods, Species::Destroyer, BUILD);
        let vis = visibility(&gearing_hull(), &bundle, false, None, None);
        let sea = vis.sea_detection.expect("sea").value();
        assert!(approx(sea, 6.597), "got {sea}");
        // on fire shifts by the same base: 6.597 + 2.0 = 8.597.
        let on_fire = vis.sea_detection_on_fire.expect("sea on fire").value();
        assert!(approx(on_fire, 8.597), "got {on_fire}");
    }

    #[test]
    fn camouflage_dist_coeff_reduces_sea_detection() {
        // visibilityDistCoeff 0.97 (camouflage concealment coef) folds into `coeff`:
        // 7.33 * 1.0 * 0.97 = 7.1101.
        let mods = [modifier("visibilityDistCoeff", 0.97)];
        let bundle = ModifierBundle::from_modifiers(&mods, Species::Destroyer, BUILD);
        let vis = visibility(&gearing_hull(), &bundle, false, None, None);
        let sea = vis.sea_detection.expect("sea").value();
        assert!(approx(sea, 7.1101), "got {sea}");
        // air also scaled by coeff: 3.41 * 0.97 = 3.3077.
        let air = vis.air_detection.expect("air").value();
        assert!(approx(air, 3.3077), "got {air}");
    }

    #[test]
    fn big_gun_visibility_penalty_applies_only_with_non_small_artillery() {
        // GMBigGunVisibilityCoeff 1.05 multiplies coeff only when has_big_gun_artillery.
        let mods = [modifier("GMBigGunVisibilityCoeff", 1.05)];
        let bundle = ModifierBundle::from_modifiers(&mods, Species::Battleship, BUILD);
        // BB-like hull (reuse Gearing's factor for the arithmetic): with big guns the
        // penalty applies: 7.33 * 1.05 = 7.6965.
        let with_guns = visibility(&gearing_hull(), &bundle, true, None, None);
        let sea = with_guns.sea_detection.expect("sea").value();
        assert!(approx(sea, 7.6965), "got {sea}");
        // Without big guns the coeff is untouched: 7.33.
        let without = visibility(&gearing_hull(), &bundle, false, None, None);
        assert_eq!(without.sea_detection, Some(Km::from(7.33)));
    }

    #[test]
    fn secondary_range_detection_floors_at_atba_range() {
        // BB-like sea detection below the secondary range -> max(sea, 7.6) = 7.6.
        let hull = HullComponentStats { visibility_factor: Some(Km::from(6.0)), ..gearing_hull() };
        let vis = visibility(&hull, &ModifierBundle::empty(Species::Battleship), false, None, Some(7.6));
        // sea = 6.0; secondary floor = max(6.0, 7.6) = 7.6.
        assert_eq!(vis.sea_detection, Some(Km::from(6.0)));
        assert_eq!(vis.secondary_range_detection, Some(Km::from(7.6)));

        // When sea exceeds the secondary range, the floor stays at sea.
        let hull_far = HullComponentStats { visibility_factor: Some(Km::from(9.0)), ..gearing_hull() };
        let vis_far = visibility(&hull_far, &ModifierBundle::empty(Species::Battleship), false, None, Some(7.6));
        assert_eq!(vis_far.secondary_range_detection, Some(Km::from(9.0)));
    }

    #[test]
    fn near_zero_smoke_coef_yields_no_smoke_detection() {
        // visibilityCoefGKInSmoke == MINIMAL_VALID_VALUE (0.01) is not > the gate -> None.
        let hull = HullComponentStats { visibility_coef_gk_in_smoke: Some(Km::from(0.01)), ..gearing_hull() };
        let vis = visibility(&hull, &ModifierBundle::empty(Species::Destroyer), false, None, None);
        assert!(vis.detection_in_smoke.is_none());

        // Below the gate -> None.
        let hull_zero = HullComponentStats { visibility_coef_gk_in_smoke: Some(Km::from(0.0)), ..gearing_hull() };
        let vis_zero = visibility(&hull_zero, &ModifierBundle::empty(Species::Destroyer), false, None, None);
        assert!(vis_zero.detection_in_smoke.is_none());
    }

    #[test]
    fn submarine_periscope_detection_applies_coeff() {
        // Periscope-depth detection only when the field is present:
        // visibilityByPeriscope 5.0 * visibilityForSubmarineCoeff 1.0 (stock) = 5.0.
        let hull = HullComponentStats { visibility_factor_by_periscope: Some(Km::from(5.0)), ..gearing_hull() };
        let vis = visibility(&hull, &ModifierBundle::empty(Species::Submarine), false, None, None);
        assert_eq!(vis.periscope_depth_detection, Some(Km::from(5.0)));
    }

    #[test]
    fn visibility_none_when_inputs_absent() {
        // Empty hull -> every field None (no fabrication, per-depth sub deferred).
        let empty = HullComponentStats::default();
        let vis = visibility(&empty, &ModifierBundle::empty(Species::Destroyer), false, None, None);
        assert!(vis.sea_detection.is_none());
        assert!(vis.sea_detection_on_fire.is_none());
        assert!(vis.air_detection.is_none());
        assert!(vis.air_detection_on_fire.is_none());
        assert!(vis.detection_in_smoke.is_none());
        assert!(vis.secondary_range_detection.is_none());
        assert!(vis.periscope_depth_detection.is_none());
    }
}