using System.Collections.Generic;

namespace Heroes.Battle
{
    /// <summary>
    /// Pure-data description of a generated battlefield. Contains no Unity
    /// references so it can be produced, serialized or tested without the
    /// engine.
    /// </summary>
    public sealed class BattlefieldConfig
    {
        public const int Width = 15;
        public const int Height = 11;

        /// <summary>Default PPU used for the VCMI-style reference layout.</summary>
        public const int ReferencePixelsPerUnit = 64;

        /// <summary>Horizontal step between hexes in the same row, in pixels (matches VCMI BattleHex::WIDTH).</summary>
        public const int HexHorizontalStepPx = 44;

        /// <summary>Vertical step between rows, in pixels (matches VCMI hex layout; rows overlap by ~10 px).</summary>
        public const int HexVerticalStepPx = 32;

        /// <summary>Horizontal shift applied to odd rows, in pixels (half of horizontal step, VCMI convention).</summary>
        public const int OddRowOffsetPx = 22;

        /// <summary>Default horizontal distance between hex centers in world units (at ReferencePixelsPerUnit).</summary>
        public const float HexHorizontalStep = (float)HexHorizontalStepPx / ReferencePixelsPerUnit;

        /// <summary>Default vertical distance between hex rows in world units (at ReferencePixelsPerUnit).</summary>
        public const float HexVerticalStep = (float)HexVerticalStepPx / ReferencePixelsPerUnit;

        public int Seed;
        public TerrainType Terrain;

        /// <summary>Identifier of the background to use (obstacle DB resolves it to a sprite).</summary>
        public string BackgroundId;

        public readonly List<PlacedObstacle> Obstacles = new List<PlacedObstacle>();
    }

    /// <summary>Single obstacle placed on the battlefield.</summary>
    public struct PlacedObstacle
    {
        /// <summary>Identifier of the obstacle definition in the database.</summary>
        public string ObstacleId;

        /// <summary>Column of the obstacle anchor hex (0..Width-1).</summary>
        public int X;

        /// <summary>Row of the obstacle anchor hex (0..Height-1).</summary>
        public int Y;
    }
}