from __future__ import annotations

MAX_LEVEL = 50
STAGE_MULT = [1.0, 1.25, 1.55, 1.9, 2.3]
GROWTH = {"attack": 0.06, "defense": 0.06, "health": 0.05, "speed": 0.04}
EVOLVE_STAGE_AT_LEVEL = {2: 10, 3: 20, 4: 30, 5: 40}   # evolve to stage 2/3/4/5 at these levels
EVOLVE_COST = {2: 2, 3: 4, 4: 6, 5: 8}                 # duplicates consumed to evolve


def compute_stats(base_stats, level: int = 1, stage: int = 1):
    """base_stats = (attack, speed, defense, health); returns leveled stats."""
    mult = STAGE_MULT[max(0, min(len(STAGE_MULT) - 1, stage - 1))]
    atk, spd, dfn, hp = base_stats

    def scale(v, growth):
        return int(v * mult * (1 + growth * (level - 1)))

    return (scale(atk, GROWTH["attack"]),
            scale(spd, GROWTH["speed"]),
            scale(dfn, GROWTH["defense"]),
            scale(hp, GROWTH["health"]))


def xp_to_next(level: int) -> int:
    return 40 * level


def stage_for_level(level: int) -> int:
    stage = 1
    for s in (2, 3, 4, 5):
        if level >= EVOLVE_STAGE_AT_LEVEL[s]:
            stage = s
    return stage


def can_evolve(level: int, stage: int, duplicates: int) -> bool:
    target = stage + 1
    if target not in EVOLVE_STAGE_AT_LEVEL:
        return False
    return level >= EVOLVE_STAGE_AT_LEVEL[target] and duplicates >= EVOLVE_COST[target]


def evolve_cost(stage: int) -> int:
    return EVOLVE_COST.get(stage + 1, 0) if stage + 1 in EVOLVE_COST else 0