using System;
using System.Collections.Generic;
using UnityEngine;

namespace Heroes.Battle
{
    /// <summary>
    /// Designer-authored obstacle entry. The sprite is placed on an anchor hex
    /// and marks a set of hexes as blocked. Relative blocked hexes are expressed
    /// as offsets from the anchor. A visual offset in world space is applied to
    /// the sprite so designers can align overhanging art.
    /// </summary>
    [CreateAssetMenu(menuName = "Heroes/Battle/Obstacle", fileName = "Obstacle")]
    public sealed class ObstacleDefinition : ScriptableObject
    {
        [Tooltip("Stable identifier used in BattlefieldConfig. Leave empty to use asset name.")]
        public string id;

        public Sprite sprite;

        [Tooltip("Obstacle class (VCMI terminology). Absolute obstacles are placed at a fixed anchor and appear at most once per battlefield.")]
        public ObstacleType type = ObstacleType.Usual;

        [Tooltip("Fixed anchor position used when type = Absolute. Ignored for Usual obstacles.")]
        public Vector2Int absoluteAnchor = new Vector2Int(7, 5);

        [Tooltip("Terrains on which this obstacle is allowed to spawn.")]
        public List<TerrainType> allowedTerrains = new List<TerrainType>();

        [Tooltip("Hexes blocked by this obstacle, relative to the anchor hex (0,0).")]
        public List<HexOffset> blockedHexes = new List<HexOffset>
        {
            new HexOffset { dx = 0, dy = 0 }
        };

        [Tooltip("World-space offset applied to the sprite when placed on the anchor hex.")]
        public Vector2 spriteOffset = Vector2.zero;

        [Tooltip("Relative weight for random selection. Higher = more frequent. Only used for Usual obstacles.")]
        [Min(0f)]
        public float weight = 1f;

        public string ResolveId() => string.IsNullOrEmpty(id) ? name : id;
    }

    /// <summary>
    /// Obstacle class mirroring VCMI's CObstacleInstance::USUAL / ABSOLUTE_OBSTACLE.
    /// Absolute obstacles define a large scripted decoration (e.g. ship wreck,
    /// giant rock) that sits at a fixed anchor; at most one appears per battle.
    /// </summary>
    public enum ObstacleType
    {
        Usual,
        Absolute,
    }

    [Serializable]
    public struct HexOffset
    {
        public int dx;
        public int dy;
    }
}