manabrew-engine 0.4.1

//! Bond effect — partner/bond mechanic for pairing creatures.
//!
//! Ported from Java's `BondEffect.java`.
//! Bond: Pair two creatures together (Soulbond).

use forge_foundation::ZoneType;

use super::EffectContext;
use crate::ids::CardId;

/// Struct form of this effect so it can participate in the
/// `SpellAbilityEffect` trait hierarchy — mirrors Java's
/// `BondEffect` class extending `SpellAbilityEffect`.
#[manabrew_engine_macros::spell_effect(BondEffect)]
fn resolve(ctx: &mut EffectContext, sa: &crate::spellability::SpellAbility) {
    let Some(source_id) = sa.source else { return };
    let controller = sa.activating_player;

    if ctx.game.card(source_id).zone != ZoneType::Battlefield {
        return;
    }

    // Find an unpaired creature to bond with
    let candidates: Vec<CardId> = ctx
        .game
        .cards
        .iter()
        .filter(|c| {
            c.zone == ZoneType::Battlefield
                && c.controller == controller
                && c.id != source_id
                && c.type_line
                    .core_types
                    .iter()
                    .any(|ct| matches!(ct, forge_foundation::CoreType::Creature))
                && c.paired_with.is_none()
        })
        .map(|c| c.id)
        .collect();

    if candidates.is_empty() {
        return;
    }

    // Optional — player may decline
    if sa.is_optional() {
        ctx.agents[controller.index()].snapshot_state(ctx.game, ctx.mana_pools);
        if !ctx.agents[controller.index()].confirm_action(
            controller,
            Some("Bond"),
            "Pair with a creature?",
            &[],
            None,
            None,
        ) {
            return;
        }
    }

    ctx.agents[controller.index()].snapshot_state(ctx.game, ctx.mana_pools);
    if let Some(partner) = ctx.agents[controller.index()].choose_single_card_for_zone_change(
        ctx.game,
        controller,
        &candidates,
        "Choose a creature to pair with",
        false,
    ) {
        ctx.game.card_mut(source_id).set_paired_with(Some(partner));
        ctx.game.card_mut(partner).set_paired_with(Some(source_id));
    }
}