using System;
using Luneraria.Core;
using Luneraria.View;

namespace Luneraria.EditorTools
{
    /// <summary>
    /// Weg 2 (Stufen) of the U5 map decision (docs/port/U5-VISUAL.md): target quality along the
    /// lanes, simpler materials in the edge zones. A point counts as lane tier while it is within
    /// LaneCorridor metres of a lane centreline, a building or the grotto — the corridor the
    /// players actually look at. Everything beyond (mountains, rim cliffs, far vegetation) gets
    /// the edge tier: colour and stone relief, no PBR maps (Surface _Quality 0).
    /// </summary>
    public static class LuneZones
    {
        /// <summary>Metres from a lane centreline (or a building) that still count as lane tier.</summary>
        public const float LaneCorridor = 22f;

        /// <summary>Distance from at to the nearest lane centreline sample.</summary>
        public static double DistanceToLanes(LuneMap map, Vec2 at)
        {
            double best = double.MaxValue;
            foreach (string lane in LuneMap.Lanes)
            {
                LanePath path = map.LanePaths[lane];
                for (int i = 0; i < path.Points.Length; i++)
                {
                    float distance = path.Points[i].DistanceTo(at);
                    if (distance < best)
                        best = distance;
                }
            }
            return best;
        }

        /// <summary>True while at is in the target-quality corridor of the slice.</summary>
        public static bool NearLane(LuneMap map, Vec2 at)
        {
            if (DistanceToLanes(map, at) <= LaneCorridor)
                return true;
            foreach (BuildingDef building in map.Buildings)
            {
                if (building.Position.DistanceTo(at) <= LaneCorridor)
                    return true;
            }
            return map.GrottoCenter().DistanceTo(at) <= LaneCorridor * 1.5;
        }

        /// <summary>Quality for the Surface shader: 1 lane tier (full PBR), 0 edge tier.</summary>
        public static float QualityOf(LuneMap map, Vec2 at)
        {
            return NearLane(map, at) ? 1f : 0f;
        }

        /// <summary>Quality of a world-space point (Unity coordinates; x is mirrored).</summary>
        public static float QualityOfWorld(LuneMap map, UnityEngine.Vector3 world)
        {
            return QualityOf(map, LuneSpace.Map(world));
        }
    }
}