DeathMod

using SoulHarvest.Common;
using Microsoft.Xna.Framework;
using System;
using System.Collections.Generic;
using System.IO;
using Terraria;
using Terraria.ID;
using Terraria.ModLoader;

namespace SoulHarvest.Projectiles;

/// <summary>
/// A continuous blood wound copied from a summoned Blood scythe's real blade-tip
/// path. Collision and rendering share the same ordered world-space curve.
/// </summary>
public sealed class ReaperBloodArcScarProjectile : ModProjectile
{
    private const int MaximumPoints = 24;
    private readonly List<Vector2> points = [];
    private SickleCombatSnapshot snapshot;
    private float baseWidth;
    private int lifetime;
    private int seed;
    private int age;
    private bool configured;
    private bool serverAuthorized;

    public override string Texture => "Terraria/Images/Projectile_0";

    internal static int Spawn(Terraria.DataStructures.IEntitySource source, int owner,
        in SickleCombatSnapshot snapshot, Vector2[] newestFirstPoints,
        int validPointCount, int phase, int actionId, float damageMultiplier)
    {
        if (Main.netMode == NetmodeID.MultiplayerClient || validPointCount < 2)
            return -1;
        List<Vector2> ordered = [];
        int usable = Math.Min(Math.Min(validPointCount, newestFirstPoints.Length),
            MaximumPoints);
        for (int index = usable - 1; index >= 0; index--)
        {
            Vector2 point = newestFirstPoints[index];
            if (!float.IsFinite(point.X) || !float.IsFinite(point.Y))
                continue;
            if (ordered.Count == 0
                || Vector2.DistanceSquared(ordered[^1], point) >= 3f * 3f)
            {
                ordered.Add(point);
            }
        }
        if (ordered.Count < 2)
            return -1;

        Vector2 center = Vector2.Zero;
        foreach (Vector2 point in ordered)
            center += point;
        center /= ordered.Count;
        Vector2 direction = (ordered[^1] - ordered[0]).SafeNormalize(Vector2.UnitX);
        int indexProjectile = Projectile.NewProjectile(source, center, direction,
            ModContent.ProjectileType<ReaperBloodArcScarProjectile>(),
            Math.Max(1, (int)Math.Round(snapshot.Damage
                * MathHelper.Clamp(damageMultiplier, 0.05f, 2f))),
            snapshot.Knockback * 0.10f, owner);
        if (indexProjectile < 0 || indexProjectile >= Main.maxProjectiles)
            return -1;

        Projectile projectile = Main.projectile[indexProjectile];
        projectile.originalDamage = snapshot.Damage;
        int level = Math.Clamp(Math.Max(1, (int)snapshot.Skill1), 1, 3);
        int stableSeed = unchecked(actionId * 16777619 + phase * 486187739
            + owner * 97);
        if (projectile.ModProjectile is ReaperBloodArcScarProjectile scar)
        {
            scar.Configure(snapshot, ordered, 10f + snapshot.StageNumber * 2.5f,
                ReaperBloodBladeProjectile.GetScarLifetime(level), stableSeed);
        }
        projectile.GetGlobalProjectile<MyGlobalProjectile>().ConfigureReaperProjectile(
            projectile, snapshot, ReaperHitKind.DamageOverTime, phase,
            direction.ToRotation(), actionId);
        projectile.localNPCHitCooldown = 24;
        ReaperProjectileHelper.SyncNewProjectile(projectile);
        return indexProjectile;
    }

    public override void SetDefaults()
    {
        Projectile.width = 4;
        Projectile.height = 4;
        Projectile.friendly = true;
        Projectile.hostile = false;
        Projectile.tileCollide = false;
        Projectile.ignoreWater = true;
        Projectile.penetrate = -1;
        Projectile.timeLeft = 300;
        Projectile.netImportant = true;
        Projectile.DamageType = DamageClass.Melee;
        Projectile.usesLocalNPCImmunity = true;
        Projectile.localNPCHitCooldown = 24;
    }

    public override bool ShouldUpdatePosition() => false;
    public override bool? CanDamage()
        => configured && age >= 4 && Projectile.timeLeft > 15 ? null : false;

    public override void AI()
    {
        if (Main.netMode == NetmodeID.Server && !serverAuthorized)
        {
            Projectile.Kill();
            return;
        }
        if (configured)
            age++;
    }

    public override bool? Colliding(Rectangle projHitbox, Rectangle targetHitbox)
    {
        float collisionPoint = 0f;
        for (int index = 1; index < points.Count; index++)
        {
            float taper = GetTaper(index - 0.5f);
            if (Collision.CheckAABBvLineCollision(targetHitbox.TopLeft(),
                targetHitbox.Size(), points[index - 1], points[index],
                Math.Max(2f, baseWidth * taper * 0.72f), ref collisionPoint))
            {
                return true;
            }
        }
        return false;
    }

    public override bool PreDraw(ref Color lightColor)
    {
        if (!configured || Main.dedServ || points.Count < 2)
            return false;
        float reveal = Smooth01(age / 9f);
        float fade = Smooth01(Projectile.timeLeft / 36f);
        int visible = Math.Clamp((int)Math.Ceiling((points.Count - 1) * reveal),
            1, points.Count - 1);
        for (int index = 1; index <= visible; index++)
        {
            float width = Math.Max(0.7f, baseWidth * GetTaper(index - 0.5f));
            ReaperBloodTrailRenderer.DrawSegment(points[index - 1], points[index],
                width, fade);
        }
        return false;
    }

    public override void SendExtraAI(BinaryWriter writer)
    {
        writer.Write(configured);
        if (!configured)
            return;
        snapshot.Write(writer);
        writer.Write(baseWidth);
        writer.Write((short)Math.Clamp(lifetime, 1, short.MaxValue));
        writer.Write(seed);
        writer.Write((short)Math.Clamp(age, 0, short.MaxValue));
        writer.Write((byte)Math.Min(points.Count, MaximumPoints));
        for (int index = 0; index < points.Count && index < MaximumPoints; index++)
            writer.WriteVector2(points[index]);
    }

    public override void ReceiveExtraAI(BinaryReader reader)
    {
        bool incoming = reader.ReadBoolean();
        if (!incoming)
        {
            if (Main.netMode != NetmodeID.Server)
                configured = false;
            return;
        }
        SickleCombatSnapshot incomingSnapshot = SickleCombatSnapshot.Read(reader);
        float incomingWidth = reader.ReadSingle();
        int incomingLifetime = reader.ReadInt16();
        int incomingSeed = reader.ReadInt32();
        int incomingAge = reader.ReadInt16();
        int count = reader.ReadByte();
        List<Vector2> incomingPoints = [];
        for (int index = 0; index < count; index++)
            incomingPoints.Add(reader.ReadVector2());
        if (Main.netMode == NetmodeID.Server)
            return;
        snapshot = incomingSnapshot;
        baseWidth = incomingWidth;
        lifetime = incomingLifetime;
        seed = incomingSeed;
        age = incomingAge;
        points.Clear();
        points.AddRange(incomingPoints);
        configured = points.Count >= 2;
    }

    private void Configure(in SickleCombatSnapshot value, List<Vector2> path,
        float width, int activeLifetime, int stableSeed)
    {
        snapshot = value;
        points.Clear();
        points.AddRange(path);
        baseWidth = MathHelper.Clamp(width, 5f, 24f);
        lifetime = Math.Clamp(activeLifetime, 60, 300);
        seed = stableSeed;
        age = 0;
        configured = points.Count >= 2;
        serverAuthorized = Main.netMode != NetmodeID.MultiplayerClient;
        Projectile.timeLeft = lifetime;
    }

    private float GetTaper(float segmentIndex)
    {
        float progress = segmentIndex / Math.Max(1f, points.Count - 1f);
        return (float)Math.Pow(Math.Max(0f, Math.Sin(progress * MathHelper.Pi)), 0.46f);
    }

    private static float Smooth01(float value)
    {
        value = MathHelper.Clamp(value, 0f, 1f);
        return value * value * (3f - 2f * value);
    }
}