using Sandbox;

namespace NZombies;

/// <summary>
/// WEAPON — a plain hitscan gun on top of s&box's BaseCombatWeapon.
///
/// Deliberately thin. The base already does everything a first gun needs:
/// tracing, damage, impact effects, muzzle presentation on every peer,
/// magazines, reserve ammo and the reload loop. Its default PrimaryAttack
/// "spends a round, shoots the volley and plays the effects" — so firing needs
/// no code at all, only configuration.
///
/// It also merges the struck hitbox's tags into the damage
/// (BaseCombatWeapon.MergeHitboxTags), which is how "head" reaches
/// Health.IsHeadshot without us tracing for it. That matters here: nZombies
/// pays 100 points for a headshot against 50 for a body shot.
///
/// Damage lands on anything with a Health component, because Health implements
/// Sandbox.Component.IDamageable and the engine's bullet path looks for that.
///
/// ⚠️ Values below are placeholders to make the loop playable, NOT the
/// original's balance. Real weapon stats come from the GMod weapon tables when
/// weapons get ported properly.
/// </summary>
public sealed class NZWeapon : BaseCombatWeapon
{
	[Property] public float ShotDamage { get; set; } = 35f;
	[Property] public int ShotPellets { get; set; } = 1;
	[Property] public float ShotRange { get; set; } = 8192f;
	[Property] public float ShotSpread { get; set; } = 0.6f;

	/// <summary>Seconds between shots — GMod's Primary.Delay.</summary>
	[Property] public float FireDelay { get; set; } = 0.12f;

	[Property] public int ClipSize { get; set; } = 30;
	[Property] public int ReserveAmmo { get; set; } = 240;

	protected override void OnStart()
	{
		// ⚠️ EVERYTHING BELOW base.OnStart(), NOT after it. The base seeds the
		// magazine during its own start, so configuring afterwards is too late:
		// Clip1 comes out as -1 ("no magazine") no matter what UsesClips says,
		// and the HUD shows -1 rounds. Set the authoring values first and the
		// base initialises from them.
		//
		// Feed from a magazine, like every nZombies weapon: the reload is part
		// of the tension, and Max Ammo as a powerup only means something if a
		// reserve pool exists.
		UsesAmmo = true;
		UsesClips = true;

		// ⚠️ ClipMaxSize / StartingAmmo are the AUTHORING properties.
		// PrimaryClipSize and MaxReserveAmmo look like the obvious ones but are
		// read-only — they're derived (PrimaryClipSize resolves to -1 when the
		// weapon feeds straight from reserve, MaxReserveAmmo comes from the
		// ammo type).
		ClipMaxSize = ClipSize;
		StartingAmmo = ReserveAmmo;

		PrimaryDelay = FireDelay;
		PrimaryAutomatic = true;

		Ballistics = new BallisticConfig
		{
			Damage = ShotDamage,
			Pellets = ShotPellets,
			Range = ShotRange,
			SpreadBase = new Vector2( ShotSpread, ShotSpread ),
		};

		base.OnStart();

		// The base does not put rounds in the magazine — it sizes it. Clip1
		// stays at -1 ("no magazine") until something loads it, so a weapon that
		// is configured correctly still reads as having no clip. Load it here.
		if ( UsesPrimaryClip && Clip1 < 0 )
			Clip1 = ClipMaxSize;

		Log.Info( $"[NZWeapon] clip {Clip1}/{ClipMaxSize}  usesPrimaryClip={UsesPrimaryClip}  "
			+ $"usesClips={UsesClips}  reserve={(HasInfiniteReserve ? "inf" : Ammo1.ToString())}" );
	}

	/// <summary>
	/// Is the reserve pool bottomless?
	///
	/// PrimaryAmmoType null means exactly that — "the magazine still forces the
	/// reload rhythm, it just never runs out". Ammo1 then reads int.MaxValue,
	/// which is correct but unprintable, so the HUD shows ∞ instead.
	///
	/// Assigning a BaseAmmoResource is what makes the reserve finite. nZombies
	/// wants finite (Max Ammo is a powerup and only means something against a
	/// pool that empties), so this is a TODO, not the intended end state.
	/// </summary>
	public bool HasInfiniteReserve => PrimaryAmmoType is null;
}