package coffee.liz.ecs

import kotlin.reflect.KClass

/**
 * An entity is a unique identifier with a collection of components.
 */
class Entity(val id: Int) {
    private val components = mutableMapOf<KClass<out Component>, Component>()

    /**
     * Add a component to this entity.
     */
    fun <T : Component> add(component: T): Entity {
        components[component::class] = component
        return this
    }

    /**
     * Remove a component from this entity.
     */
    fun <T : Component> remove(type: KClass<T>): Entity {
        components.remove(type)
        return this
    }

    /**
     * Get a component by type.
     */
    @Suppress("UNCHECKED_CAST")
    fun <T : Component> get(type: KClass<T>): T? {
        return components[type] as? T
    }

    /**
     * Check if entity has a component.
     */
    fun <T : Component> has(type: KClass<T>): Boolean {
        return components.containsKey(type)
    }

    /**
     * Check if entity has all specified components.
     */
    fun hasAll(vararg types: KClass<out Component>): Boolean {
        return types.all { components.containsKey(it) }
    }

    /**
     * Get all component types on this entity.
     */
    fun componentTypes(): Set<KClass<out Component>> {
        return components.keys.toSet()
    }

    override fun equals(other: Any?): Boolean {
        if (this === other) return true
        if (other !is Entity) return false
        return id == other.id
    }

    override fun hashCode(): Int = id

    override fun toString(): String = "Entity($id)"
}

// Convenience extensions for cleaner syntax
inline fun <reified T : Component> Entity.get(): T? = get(T::class)
inline fun <reified T : Component> Entity.has(): Boolean = has(T::class)
inline fun <reified T : Component> Entity.remove(): Entity = remove(T::class)