using UnityEngine;

namespace MazeGen
{
    /// <summary>
    /// One participant in a battle - either an agent or a monster instance - behind a single
    /// interface so <see cref="CombatResolver"/> doesn't need to branch on which it is.
    ///
    /// Wraps the *live* <see cref="CharacterSheet"/>, not a copy: resolving a fight mutates real
    /// agent and monster health, which is exactly what "only the result of the fight has changed
    /// for that room" means. <see cref="StartHealth"/> is snapshotted before resolution purely so
    /// the arena playback can animate health draining down from where it actually started.
    /// </summary>
    public class Combatant
    {
        public const int TeamAgents = 0;
        public const int TeamMonsters = 1;

        /// <summary>Index of this combatant within its own battle. Combat events refer to these.</summary>
        public readonly int Id;
        public readonly int Team;
        public readonly string Name;
        public readonly Color Color;

        /// <summary>Set for agent combatants, null for monsters.</summary>
        public readonly MazeAgent Agent;

        /// <summary>Set for monster combatants, null for agents.</summary>
        public readonly MonsterEncounter.MonsterInstance Monster;

        public readonly CharacterSheet Sheet;

        /// <summary>Health at the moment the battle was resolved, for playback purposes.</summary>
        public readonly float StartHealth;

        public bool IsAgent => Agent != null;
        public bool IsAlive => Sheet.Stats.IsAlive;

        /// <summary>
        /// Base max health, not GetEffectiveMaxHealth(): CharacterStats.CurrentHealth is clamped
        /// to the base value, so using the effective one here would give health bars that can
        /// never fill up whenever equipment grants a health bonus.
        /// </summary>
        public float MaxHealth => Mathf.Max(1f, Sheet.Stats.MaxHealth);

        private Combatant(int id, int team, string name, Color color, MazeAgent agent, MonsterEncounter.MonsterInstance monster, CharacterSheet sheet)
        {
            Id = id;
            Team = team;
            Name = name;
            Color = color;
            Agent = agent;
            Monster = monster;
            Sheet = sheet;
            StartHealth = sheet.Stats.CurrentHealth;
        }

        public static Combatant ForAgent(int id, MazeAgent agent, Color color)
            => new Combatant(id, TeamAgents, agent.CharacterSheet.Name, color, agent, null, agent.CharacterSheet);

        public static Combatant ForMonster(int id, MonsterEncounter.MonsterInstance monster)
            => new Combatant(id, TeamMonsters, monster.Template.MonsterName, monster.Template.Color, null, monster, monster.CharacterSheet);
    }
}