using UnityEngine;

namespace ProjectM.Client
{
    /// <summary>
    /// Shared asset-free procedural-FX toolkit for the client presentation FEEDBACK systems (Combat / Structure /
    /// World / Ambient), which previously each carried a near-identical private copy. Pure UnityEngine (no ECS), so
    /// it stays a plain static helper. MakeBurst takes the owning FX-root transform + the per-use gravity / shape
    /// radius / size-tail that were the ONLY real differences between the old copies (Combat 0/0.06/0.2,
    /// Structure 0.3/0.18/0.15, World 0.25/0.10/0.2). MakeClip folds in the noise + envelope-decay knobs that were
    /// the only differences between the CombatFeedback MakeClip and the AmbientAudio MakeSting.
    /// </summary>
    public static class FeedbackFx
    {
        public static AudioClip MakeClip(string name, float f0, float f1, float dur, float vol, bool noise = false, float decay = 5f)
        {
            const int rate = 44100;
            int len = Mathf.Max(16, (int)(dur * rate));
            var clip = AudioClip.Create(name, len, 1, rate, false);
            var data = new float[len];
            var rng = new System.Random(name.Length * 9973 + 7);
            float phase = 0f;
            for (int i = 0; i < len; i++)
            {
                float t = i / (float)len;
                float env = Mathf.Exp(-decay * t);
                float freq = Mathf.Lerp(f0, f1, t);
                phase += 2f * Mathf.PI * freq / rate;
                float s = noise ? (float)(rng.NextDouble() * 2.0 - 1.0) : Mathf.Sin(phase);
                data[i] = s * env * vol;
            }
            clip.SetData(data, 0);
            return clip;
        }

        public static Material MakeParticleMaterial(string name = "FeedbackParticle")
        {
            // Sprites/Default is an always-included transparent vertex-coloured shader (reliable billboarded sparks;
            // HDR start colours still push past the bloom threshold); fall back through URP unlit / Unlit/Color.
            Shader sh = Shader.Find("Sprites/Default");
            if (sh == null) sh = Shader.Find("Universal Render Pipeline/Particles/Unlit");
            if (sh == null) sh = Shader.Find("Unlit/Color");
            return new Material(sh) { name = name };
        }

        public static ParticleSystem MakeBurst(Transform parent, string name, Material mat, Color color,
            float size, float speed, float life, int max,
            float gravity = 0f, float shapeRadius = 0.06f, float sizeTail = 0.2f)
        {
            var go = new GameObject(name);
            go.transform.SetParent(parent, false);
            var ps = go.AddComponent<ParticleSystem>();

            var main = ps.main;
            main.loop = false;
            main.playOnAwake = false;
            main.startLifetime = life;
            main.startSpeed = speed;
            main.startSize = size;
            main.startColor = color;
            main.maxParticles = max;
            main.gravityModifier = gravity;
            main.simulationSpace = ParticleSystemSimulationSpace.World;

            var emission = ps.emission;
            emission.enabled = false; // manual Emit(count)

            var shape = ps.shape;
            shape.enabled = true;
            shape.shapeType = ParticleSystemShapeType.Sphere;
            shape.radius = shapeRadius;

            var colOverLife = ps.colorOverLifetime;
            colOverLife.enabled = true;
            var grad = new Gradient();
            grad.SetKeys(
                new[] { new GradientColorKey(Color.white, 0f), new GradientColorKey(Color.white, 1f) },
                new[] { new GradientAlphaKey(1f, 0f), new GradientAlphaKey(0f, 1f) });
            colOverLife.color = new ParticleSystem.MinMaxGradient(grad);

            var sizeOverLife = ps.sizeOverLifetime;
            sizeOverLife.enabled = true;
            sizeOverLife.size = new ParticleSystem.MinMaxCurve(1f, AnimationCurve.Linear(0f, 1f, 1f, sizeTail));

            var renderer = ps.GetComponent<ParticleSystemRenderer>();
            renderer.material = mat;
            renderer.renderMode = ParticleSystemRenderMode.Billboard;
            return ps;
        }

        public static void EmitTinted(ParticleSystem ps, Vector3 pos, int count, Color tint)
        {
            if (ps == null) return;
            var main = ps.main;
            main.startColor = tint;
            ps.transform.position = pos;
            ps.Emit(count);
        }

        public static void EmitAt(ParticleSystem ps, Vector3 pos, int count)
        {
            if (ps == null) return;
            ps.transform.position = pos;
            ps.Emit(count);
        }

        public static void PlayClip(AudioClip clip, Vector3 pos, float vol)
        {
            if (clip == null) return;
            AudioSource.PlayClipAtPoint(clip, pos, vol * GameVolume.Sfx);
        }
    }
}