using Sandbox;

namespace NZombies;

/// <summary>
/// THE GENERIC STATS OF THE TIER-4/5 AUGMENTS (2026-10-04, Sbox nzombies/Docs/WEAPON_TECH_BY_CLASS.md): every owned
/// node's `s.*` and `f.*` magnitudes, combined, for one weapon.
///
/// ⚠️ TIERS 1–3 USE THEM TOO SINCE 2026-10-04 (WEAPON_TECH_TIERS_1_3.md): Floated Barrel, Quick Sling, Steel Core, Gunner's
/// Plate, Backup Sights… are made only of these. They brought one new key, `s.reserve+` (Side Pouch's flat +30 reserve),
/// read once at `NZPlayer`'s reserve site.
///
/// ⛔ ONE ACCESSOR PER STAT SITE, NOT ONE CALL PER NODE. The per-class redesign brought about seventy augments, most of
/// them made only of stats (×1.6 damage, half the range, +3 penetration…). Wiring each by id at every site would be
/// seventy names to remember in a dozen files; instead each stat site reads its stat once from here, and a node made
/// of stats needs no code at all. The catalogue is still the only source of every number (`WeaponTech`'s rule).
///
/// ⚠️ ONLY `s.*` AND `f.*` NAMES ARE READ HERE. The old nodes' magnitudes (`rpm`, `clip`, `walk`…) are wired by id at
/// their own sites; giving the new stats their own prefix is what keeps an old node from being counted twice.
///
/// ⚠️ THROUGH `NZPlayer.TechOrNull`, NOT `TechFor`: these are read several times a frame (`EffectiveFiringType`,
/// `GetRealSpread`), and `TechFor` allocates a new list for every gun without tech.
///
/// ⚠️ AMPLIFIED like every other magnitude (`TechEffects.AmpMag`): a multiplier obeys `nz_tech_amp`, a count or a
/// switch (`Multiplier: false`) does not.
/// </summary>
public static class TechStats
{
	/// <summary>The product of every owned node's <paramref name="stat"/> multiplier on this prefab. 1 when none.</summary>
	public static float Mul( NZPlayer player, string prefab, string stat )
	{
		if ( !player.IsValid() || string.IsNullOrEmpty( prefab ) ) return 1f;

		var f = 1f;
		var owned = player.TechOrNull( prefab );
		if ( owned is null ) return 1f;

		foreach ( var id in owned )
		{
			var extra = WeaponTech.Find( id )?.Extra;
			if ( extra is null ) continue;

			foreach ( var m in extra )
				if ( m.Name == stat ) f *= TechEffects.AmpMag( m.Value, m.Multiplier );
		}

		return f;
	}

	/// <summary>The sum of every owned node's <paramref name="stat"/> addend on this prefab. 0 when none.</summary>
	public static float Add( NZPlayer player, string prefab, string stat )
	{
		if ( !player.IsValid() || string.IsNullOrEmpty( prefab ) ) return 0f;

		var sum = 0f;
		var owned = player.TechOrNull( prefab );
		if ( owned is null ) return 0f;

		foreach ( var id in owned )
		{
			var extra = WeaponTech.Find( id )?.Extra;
			if ( extra is null ) continue;

			foreach ( var m in extra )
				if ( m.Name == stat ) sum += m.Value;
		}

		return sum;
	}

	/// <summary>Does any owned node on this prefab switch <paramref name="flag"/> on.</summary>
	public static bool Flag( NZPlayer player, string prefab, string flag )
	{
		if ( !player.IsValid() || string.IsNullOrEmpty( prefab ) ) return false;

		var owned = player.TechOrNull( prefab );
		if ( owned is null ) return false;

		foreach ( var id in owned )
		{
			var extra = WeaponTech.Find( id )?.Extra;
			if ( extra is null ) continue;

			foreach ( var m in extra )
				if ( m.Name == flag && m.Value != 0f ) return true;
		}

		return false;
	}

	/// <summary>A value an owned node SETS (`s.pellets=`), or <paramref name="ifAbsent"/>. The last owned one wins.</summary>
	public static float Set( NZPlayer player, string prefab, string stat, float ifAbsent )
	{
		if ( !player.IsValid() || string.IsNullOrEmpty( prefab ) ) return ifAbsent;

		var v = ifAbsent;
		var owned = player.TechOrNull( prefab );
		if ( owned is null ) return ifAbsent;

		foreach ( var id in owned )
		{
			var extra = WeaponTech.Find( id )?.Extra;
			if ( extra is null ) continue;

			foreach ( var m in extra )
				if ( m.Name == stat ) v = m.Value;
		}

		return v;
	}

	// ── the weapon's own reads (read-time sites) ────────────────────────────────────────

	/// <summary>
	/// The owner and prefab of a weapon, the way `TechEffects.Has` resolves them: from the WEAPON, never from whatever
	/// the player is holding, so one slot's tech never leaks onto the other.
	/// </summary>
	static (NZPlayer player, string prefab) Of( Component weapon )
	{
		if ( !weapon.IsValid() ) return (null, null);

		var player = weapon.Components.Get<NZPlayer>( FindMode.InAncestors | FindMode.Enabled );
		var prefab = Rarity.PrefabOf( weapon as SWB.Base.Weapon );
		return (player, prefab);
	}

	public static float Mul( Component weapon, string stat )
	{
		var (p, prefab) = Of( weapon );
		return Mul( p, prefab, stat );
	}

	public static float Add( Component weapon, string stat )
	{
		var (p, prefab) = Of( weapon );
		return Add( p, prefab, stat );
	}

	public static bool Flag( Component weapon, string flag )
	{
		var (p, prefab) = Of( weapon );
		return Flag( p, prefab, flag );
	}

	// ── the victim's side (a relayed hit has no weapon on the host) ─────────────────────

	public static float Mul( in TechEffects.TechRef tech, string stat )
		=> tech.Valid ? Mul( tech.Player, tech.Prefab, stat ) : 1f;

	public static bool Flag( in TechEffects.TechRef tech, string flag )
		=> tech.Valid && Flag( tech.Player, tech.Prefab, flag );
}