Monster.sol

//SPDX-License-Identifier: MIT
pragma solidity 0.8.7;

import "./Combat.sol";
import "./Random.sol";

library Monster {
    struct MonsterCodex {
        uint8 id;
        uint8 hit_dice_count;
        uint8 hit_dice_sides;
        int8 hit_dice_modifier;
        int8 initiative_bonus;
        uint8 armor_class;
        uint16 challenge_rating;
        uint8[6] abilities;
        int8[28] attacks; // layout: [attack_bonus, critical_modifier, critical_multiplier, damage_dice_count, damage_dice_sides, damage_modifier, damage_type.. x4]
        string name;
    }

    function standard_hit_points(MonsterCodex memory monster)
        public
        pure
        returns (int16)
    {
        return
            int16(
                uint16(
                    (monster.hit_dice_count *
                        monster.hit_dice_sides -
                        monster.hit_dice_count) /
                        2 +
                        monster.hit_dice_count
                )
            ) + monster.hit_dice_modifier;
    }

    function roll_hit_points(MonsterCodex memory monster, uint256 token)
        public
        view
        returns (int16)
    {
        int16 roll = int16(
            uint16(
                Random.dn(
                    9409069218745053777,
                    token,
                    monster.hit_dice_count,
                    monster.hit_dice_sides
                )
            )
        );
        return roll + monster.hit_dice_modifier;
    }

    function monster_combatant(
        uint256 token,
        address mint,
        Monster.MonsterCodex memory monster_codex
    ) public view returns (Combat.Combatant memory combatant) {
        (uint8 initiative_roll, int8 initiative_score) = Roll.initiative(
            token,
            Attributes.compute_modifier(monster_codex.abilities[1]),
            monster_codex.initiative_bonus
        );

        combatant.mint = mint;
        combatant.token = token;
        combatant.initiative_roll = initiative_roll;
        combatant.initiative_score = initiative_score;
        combatant.hit_points = standard_hit_points(monster_codex);
        combatant.armor_class = monster_codex.armor_class;
        combatant.attacks = monster_codex.attacks;
    }

    function monster_by_id(uint8 id)
        public
        pure
        returns (MonsterCodex memory monster)
    {
        if (id == 1) {
            return kobold();
        } else if (id == 2) {
            return dire_rat();
        } else if (id == 3) {
            return goblin();
        } else if (id == 4) {
            return gnoll();
        } else if (id == 5) {
            return grimlock();
        } else if (id == 6) {
            return black_bear();
        } else if (id == 7) {
            return ogre();
        } else if (id == 8) {
            return dire_boar();
        } else if (id == 9) {
            return dire_wolverine();
        } else if (id == 10) {
            return troll();
        } else if (id == 11) {
            return ettin();
        } else if (id == 12) {
            return hill_giant();
        } else if (id == 13) {
            return stone_giant();
        }
    }

    function kobold() public pure returns (MonsterCodex memory monster) {
        monster.id = 1;
        monster.challenge_rating = 25; // CR 1/4
        monster.hit_dice_count = 1;
        monster.hit_dice_sides = 8;
        monster.hit_dice_modifier = 0;
        monster.initiative_bonus = 0;
        monster.armor_class = 15;
        monster.abilities = [9, 13, 10, 10, 9, 8];
        Combat.pack_attack(1, 0, 3, 1, 2, -1, 2, 0, monster.attacks);
        monster.name = "Kobold";
    }

    function dire_rat() public pure returns (MonsterCodex memory monster) {
        monster.id = 2;
        monster.challenge_rating = 33; // CR 1/3
        monster.hit_dice_count = 1;
        monster.hit_dice_sides = 8;
        monster.hit_dice_modifier = 1;
        monster.initiative_bonus = 0;
        monster.armor_class = 15;
        monster.abilities = [10, 17, 12, 1, 12, 4];
        Combat.pack_attack(4, 0, 2, 1, 4, 0, 3, 0, monster.attacks);
        monster.name = "Dire Rat";
    }

    function goblin() public pure returns (MonsterCodex memory monster) {
        monster.id = 3;
        monster.challenge_rating = 33; // CR 1/3
        monster.hit_dice_count = 1;
        monster.hit_dice_sides = 8;
        monster.hit_dice_modifier = 1;
        monster.initiative_bonus = 0;
        monster.armor_class = 15;
        monster.abilities = [11, 13, 12, 10, 9, 6];
        Combat.pack_attack(2, 0, 2, 1, 6, 0, 1, 0, monster.attacks);
        monster.name = "Goblin";
    }

    function gnoll() public pure returns (MonsterCodex memory monster) {
        monster.id = 4;
        monster.challenge_rating = 100; // CR 1
        monster.hit_dice_count = 2;
        monster.hit_dice_sides = 8;
        monster.hit_dice_modifier = 2;
        monster.initiative_bonus = 0;
        monster.armor_class = 15;
        monster.abilities = [15, 10, 13, 8, 11, 8];
        Combat.pack_attack(3, 0, 3, 1, 8, 2, 3, 0, monster.attacks);
        monster.name = "Gnoll";
    }

    function grimlock() public pure returns (MonsterCodex memory monster) {
        monster.id = 5;
        monster.challenge_rating = 100; // CR 1
        monster.hit_dice_count = 2;
        monster.hit_dice_sides = 8;
        monster.hit_dice_modifier = 2;
        monster.initiative_bonus = 0;
        monster.armor_class = 15;
        monster.abilities = [15, 13, 13, 10, 8, 6];
        Combat.pack_attack(4, 0, 3, 1, 8, 3, 3, 0, monster.attacks);
        monster.name = "Grimlock";
    }

    function black_bear() public pure returns (MonsterCodex memory monster) {
        monster.id = 6;
        monster.challenge_rating = 200; // CR 2
        monster.hit_dice_count = 3;
        monster.hit_dice_sides = 8;
        monster.hit_dice_modifier = 6;
        monster.initiative_bonus = 0;
        monster.armor_class = 13;
        monster.abilities = [19, 13, 15, 2, 12, 6];
        Combat.pack_attack(6, 0, 2, 1, 4, 4, 3, 0, monster.attacks);
        Combat.pack_attack(6, 0, 2, 1, 4, 4, 3, 1, monster.attacks);
        Combat.pack_attack(1, 0, 2, 1, 6, 2, 3, 2, monster.attacks);
        monster.name = "Black Bear";
    }

    function ogre() public pure returns (MonsterCodex memory monster) {
        monster.id = 7;
        monster.challenge_rating = 300; // CR 3
        monster.hit_dice_count = 4;
        monster.hit_dice_sides = 8;
        monster.hit_dice_modifier = 11;
        monster.initiative_bonus = 0;
        monster.armor_class = 16;
        monster.abilities = [21, 8, 15, 6, 10, 7];
        Combat.pack_attack(8, 0, 2, 2, 8, 7, 1, 0, monster.attacks);
        monster.name = "Ogre";
    }

    function dire_boar() public pure returns (MonsterCodex memory monster) {
        monster.id = 8;
        monster.challenge_rating = 400; // CR 4
        monster.hit_dice_count = 7;
        monster.hit_dice_sides = 8;
        monster.hit_dice_modifier = 21;
        monster.initiative_bonus = 0;
        monster.armor_class = 15;
        monster.abilities = [27, 10, 17, 2, 13, 8];
        Combat.pack_attack(12, 0, 2, 1, 8, 12, 2, 0, monster.attacks);
        monster.name = "Dire Boar";
    }

    function dire_wolverine()
        public
        pure
        returns (MonsterCodex memory monster)
    {
        monster.id = 9;
        monster.challenge_rating = 400; // CR 4
        monster.hit_dice_count = 5;
        monster.hit_dice_sides = 8;
        monster.hit_dice_modifier = 23;
        monster.initiative_bonus = 0;
        monster.armor_class = 16;
        monster.abilities = [22, 17, 19, 2, 12, 10];
        Combat.pack_attack(8, 0, 2, 1, 6, 6, 3, 0, monster.attacks);
        Combat.pack_attack(8, 0, 2, 1, 6, 6, 3, 1, monster.attacks);
        Combat.pack_attack(3, 0, 2, 1, 8, 3, 3, 2, monster.attacks);
        monster.name = "Dire Wolverine";
    }

    function troll() public pure returns (MonsterCodex memory monster) {
        monster.id = 10;
        monster.challenge_rating = 500; // CR 5
        monster.hit_dice_count = 6;
        monster.hit_dice_sides = 8;
        monster.hit_dice_modifier = 36;
        monster.initiative_bonus = 0;
        monster.armor_class = 16;
        monster.abilities = [27, 10, 17, 2, 13, 8];
        Combat.pack_attack(9, 0, 2, 1, 6, 6, 3, 0, monster.attacks);
        Combat.pack_attack(9, 0, 2, 1, 6, 6, 3, 1, monster.attacks);
        Combat.pack_attack(4, 0, 2, 1, 6, 3, 2, 2, monster.attacks);
        monster.name = "Troll";
    }

    function ettin() public pure returns (MonsterCodex memory monster) {
        monster.id = 11;
        monster.challenge_rating = 600; // CR 6
        monster.hit_dice_count = 10;
        monster.hit_dice_sides = 8;
        monster.hit_dice_modifier = 20;
        monster.initiative_bonus = 4; // improved initiative feat
        monster.armor_class = 18;
        monster.abilities = [27, 10, 17, 2, 13, 8];
        Combat.pack_attack(12, 0, 2, 2, 6, 6, 1, 0, monster.attacks);
        Combat.pack_attack(7, 0, 2, 2, 6, 6, 1, 1, monster.attacks);
        monster.name = "Ettin";
    }

    function hill_giant() public pure returns (MonsterCodex memory monster) {
        monster.id = 12;
        monster.challenge_rating = 700; // CR 7
        monster.hit_dice_count = 12;
        monster.hit_dice_sides = 8;
        monster.hit_dice_modifier = 48;
        monster.initiative_bonus = 0;
        monster.armor_class = 20;
        monster.abilities = [25, 8, 19, 6, 10, 7];
        Combat.pack_attack(16, 0, 2, 2, 8, 10, 1, 0, monster.attacks);
        Combat.pack_attack(11, 0, 2, 2, 8, 10, 1, 1, monster.attacks);
        monster.name = "Hill Giant";
    }

    function stone_giant() public pure returns (MonsterCodex memory monster) {
        monster.id = 13;
        monster.challenge_rating = 800; // CR 8
        monster.hit_dice_count = 14;
        monster.hit_dice_sides = 8;
        monster.hit_dice_modifier = 56;
        monster.initiative_bonus = 0;
        monster.armor_class = 25;
        monster.abilities = [27, 15, 19, 10, 12, 11];
        Combat.pack_attack(17, 0, 2, 2, 8, 12, 1, 0, monster.attacks);
        Combat.pack_attack(12, 0, 2, 2, 8, 12, 1, 1, monster.attacks);
        monster.name = "Stone Giant";
    }
}