manabrew-engine 0.4.1

//! Replacement logic for `Event$ DamageDone`.
//!
//! Mirrors Java `ReplaceDamage.java` in `forge/game/replacement/`.

use crate::card::Card;
use crate::game::GameState;
use crate::ids::CardId;
use crate::parsing::compare::compare_expr;

use super::replacement_effect::ReplacementEffect;
use super::replacement_handler::ReplacementEvent;
use super::replacement_handler::{execute_replace_with_numeric_update, resolve_replace_value};
use super::replacement_result::ReplacementResult;
use super::replacement_type::ReplacementType;
use crate::card_trait_base::CardTrait;

/// Mirrors Java `ReplaceDamage.canReplace()`.
pub fn can_replace(
    effect: &ReplacementEffect,
    event: &ReplacementEvent,
    game: &GameState,
    source_card: &Card,
) -> bool {
    if effect.event != ReplacementType::DamageDone {
        return false;
    }
    let (damage_source, target_player, target_card, amount, is_combat) = match event {
        ReplacementEvent::DamageToCard {
            target,
            amount,
            source,
            is_combat,
        } => (*source, None, Some(*target), *amount, *is_combat),
        ReplacementEvent::DamageToPlayer {
            target,
            amount,
            source,
            is_combat,
        } => (*source, Some(*target), None, *amount, *is_combat),
        _ => return false,
    };
    if amount <= 0 {
        return false;
    }
    if let Some(valid_source) = effect.ir.valid_source_selector.as_ref() {
        let Some(source_id) = damage_source else {
            return false;
        };
        if !effect.matches_compiled_valid_card(valid_source, game.card(source_id), source_card) {
            return false;
        }
    }
    if let Some(valid_target) = effect.ir.valid_target_selector.as_ref() {
        let target_matches = if let Some(target) = target_player {
            crate::card::valid_filter::matches_valid(
                &valid_target.as_raw(),
                None,
                Some(target),
                source_card,
                source_card.controller,
            )
        } else if let Some(target) = target_card {
            effect.matches_compiled_valid_card(valid_target, game.card(target), source_card)
        } else {
            false
        };
        if !target_matches {
            return false;
        }
    }
    if let Some(wants_max_speed) = effect.ir.max_speed {
        if wants_max_speed != (game.player(source_card.controller).speed == 4) {
            return false;
        }
    }
    if let Some(wants_combat) = effect.ir.is_combat {
        if wants_combat != is_combat {
            return false;
        }
    }
    if let Some(damage_amount) = effect.ir.damage_amount_text.as_deref() {
        let threshold = damage_amount.get(2..).unwrap_or("");
        let rhs = resolve_replace_value(threshold, game, source_card.id, event)
            .or_else(|| threshold.parse::<i32>().ok())
            .unwrap_or(0);
        let cmp = format!("{}{}", damage_amount.get(..2).unwrap_or("GE"), rhs);
        if !compare_expr(amount, &cmp) {
            return false;
        }
    }
    true
}

/// Mirrors Java `ReplacementHandler.executeReplacement()` for DamageDone.
pub fn execute(
    effect: &ReplacementEffect,
    event: &mut ReplacementEvent,
    game: &GameState,
    source_card_id: CardId,
) -> ReplacementResult {
    match event {
        ReplacementEvent::DamageToCard { .. } | ReplacementEvent::DamageToPlayer { .. } => {}
        _ => return ReplacementResult::NotReplaced,
    }
    if effect.prevents() {
        match event {
            ReplacementEvent::DamageToCard { amount, .. } => *amount = 0,
            ReplacementEvent::DamageToPlayer { amount, .. } => *amount = 0,
            _ => {}
        }
        return ReplacementResult::Prevented;
    }
    // Handle built-in replacement modes before SVar chain.
    if let Some(replace) = effect.replace_with() {
        match replace {
            "DmgTwice" | "DoubleDamage" => {
                match event {
                    ReplacementEvent::DamageToCard { amount, .. } => *amount *= 2,
                    ReplacementEvent::DamageToPlayer { amount, .. } => *amount *= 2,
                    _ => {}
                }
                return ReplacementResult::Updated;
            }
            "DmgHalf" | "HalfDamage" => {
                match event {
                    ReplacementEvent::DamageToCard { amount, .. } => *amount = (*amount + 1) / 2,
                    ReplacementEvent::DamageToPlayer { amount, .. } => *amount = (*amount + 1) / 2,
                    _ => {}
                }
                return ReplacementResult::Updated;
            }
            "DmgPlus1" => {
                match event {
                    ReplacementEvent::DamageToCard { amount, .. } => *amount += 1,
                    ReplacementEvent::DamageToPlayer { amount, .. } => *amount += 1,
                    _ => {}
                }
                return ReplacementResult::Updated;
            }
            "DmgPlus2" => {
                match event {
                    ReplacementEvent::DamageToCard { amount, .. } => *amount += 2,
                    ReplacementEvent::DamageToPlayer { amount, .. } => *amount += 2,
                    _ => {}
                }
                return ReplacementResult::Updated;
            }
            _ => {}
        }
    }
    if let Some(result) =
        execute_replace_with_numeric_update(effect, event, game, source_card_id, "DamageAmount")
    {
        return result;
    }
    ReplacementResult::Replaced
}