elseware/src/ship/drops/mod.rs

// TODO: there is some structure duplication that occurs here:
// the rare and box tables instantiate their own copies of the
// generic drop tables as they need them to apply their modifiers
// to their drops


mod drop_table;
mod rare_drop_table;
mod generic_weapon;
mod generic_armor;
mod generic_shield;
mod generic_unit;
mod tool_table;
mod tech_table;
mod box_drop_table;

use std::collections::HashMap;
use std::fs::File;
use std::path::PathBuf;
use std::io::Read;
use serde::{Serialize, Deserialize};
use rand::{Rng, SeedableRng};

use crate::ship::monster::MonsterType;
use crate::ship::room::{Difficulty, Episode};
use crate::ship::map::MapArea;
use crate::entity::character::SectionID;
use crate::ship::drops::generic_weapon::GenericWeaponTable;
use crate::ship::drops::generic_armor::GenericArmorTable;
use crate::ship::drops::generic_shield::GenericShieldTable;
use crate::ship::drops::generic_unit::GenericUnitTable;
use crate::ship::drops::tool_table::ToolTable;
use crate::ship::drops::rare_drop_table::RareDropTable;
use crate::ship::drops::box_drop_table::BoxDropTable;
use crate::ship::map::MapObject;
use crate::entity::item::{weapon, armor, shield, unit, mag, tool, tech};


fn data_file_path(episode: Episode, difficulty: Difficulty, section_id: SectionID, filename: &str) -> PathBuf {
    let mut path = PathBuf::from("data/drops/");
    path.push(episode.to_string());
    path.push(difficulty.to_string().to_lowercase());
    path.push(section_id.to_string().to_lowercase());
    path.push(filename);
    path
}

pub fn load_data_file<T: serde::de::DeserializeOwned>(episode: Episode, difficulty: Difficulty, section_id: SectionID, filename: &str) -> T {
    let path = data_file_path(episode, difficulty, section_id, filename);
    let mut f = File::open(path).unwrap();
    let mut s = String::new();
    f.read_to_string(&mut s);

    toml::from_str::<T>(s.as_str()).unwrap()
}


#[derive(Debug, Serialize, Deserialize, Copy, Clone)]
pub enum MonsterDropType {
    #[serde(rename = "weapon")]
    Weapon,
    #[serde(rename = "armor")]
    Armor,
    #[serde(rename = "shield")]
    Shield,
    #[serde(rename = "unit")]
    Unit,
    #[serde(rename = "none")]
    None,
}

#[derive(Debug, Serialize, Deserialize, Copy, Clone)]
pub struct MonsterDropStats {
    pub dar: u32,
    pub drop_type: MonsterDropType,
    pub min_meseta: u32,
    pub max_meseta: u32,
}

#[derive(Clone, Debug, PartialEq)]
pub enum ItemDropType {
    Weapon(weapon::Weapon),
    Armor(armor::Armor),
    Shield(shield::Shield),
    Unit(unit::Unit),
    Tool(tool::Tool),
    //Tools(Vec<tool::Tool>),
    TechniqueDisk(tech::TechniqueDisk),
    Mag(mag::Mag),
    Meseta(u32),
}

pub struct ItemDrop {
    pub map_area: MapArea,
    pub x: f32,
    pub y: f32,
    pub z: f32,
    pub item: ItemDropType,
}

impl ItemDrop {
    pub fn as_client_bytes(&self) -> u8 {
        0
    }
}



pub struct DropTable<R: Rng + SeedableRng> {
    monster_stats: HashMap<MonsterType, MonsterDropStats>,
    rare_table: RareDropTable,
    weapon_table: GenericWeaponTable,
    armor_table: GenericArmorTable,
    shield_table: GenericShieldTable,
    unit_table: GenericUnitTable,
    tool_table: ToolTable,
    box_table: BoxDropTable,
    rng: R,
}


impl<R: Rng + SeedableRng> DropTable<R> {
    pub fn new(episode: Episode, difficulty: Difficulty, section_id: SectionID) -> DropTable<R> {
        let monster_stats: HashMap<String, MonsterDropStats> = load_data_file(episode, difficulty, section_id, "monster_dar.toml");
        
        DropTable {
            monster_stats: monster_stats.into_iter().map(|(m, s)| (m.parse().unwrap(), s)).collect(),
            rare_table: RareDropTable::new(episode, difficulty, section_id),
            weapon_table: GenericWeaponTable::new(episode, difficulty, section_id),
            armor_table: GenericArmorTable::new(episode, difficulty, section_id),
            shield_table: GenericShieldTable::new(episode, difficulty, section_id),
            unit_table: GenericUnitTable::new(episode, difficulty, section_id),
            tool_table: ToolTable::new(episode, difficulty, section_id),
            box_table: BoxDropTable::new(episode, difficulty, section_id),
            rng: R::from_entropy(),
        }
    }

    fn generate_meseta(&mut self, monster: &MonsterDropStats) -> Option<ItemDropType> {
        Some(ItemDropType::Meseta(self.rng.gen_range(monster.min_meseta, monster.max_meseta)))
    }

    fn generate_typed_drop(&mut self, map_area: &MapArea, monster: &MonsterDropStats) -> Option<ItemDropType> {
        match monster.drop_type {
            MonsterDropType::Weapon => self.weapon_table.get_drop(map_area, &mut self.rng),
            MonsterDropType::Armor => self.armor_table.get_drop(map_area, &mut self.rng),
            MonsterDropType::Shield => self.shield_table.get_drop(map_area, &mut self.rng),
            MonsterDropType::Unit => self.unit_table.get_drop(map_area, &mut self.rng),
            MonsterDropType::None => None,
        }
    }

    pub fn get_drop(&mut self, map_area: &MapArea, monster: &MonsterType) -> Option<ItemDropType> {
        let monster_stat = *self.monster_stats.get(monster)?;

        let drop_anything = self.rng.gen_range(0, 100);
        if drop_anything > monster_stat.dar {
            return None;
        }

        if let Some(item) = self.rare_table.get_drop(map_area, &monster, &mut self.rng) {
            return Some(item);
        }

        let drop_type = self.rng.gen_range(0, 3);
        
        match drop_type {
            0 => {
                self.generate_meseta(&monster_stat)
            },
            1 => {
                self.tool_table.get_drop(map_area, &mut self.rng)
            },
            2 => {
                self.generate_typed_drop(map_area, &monster_stat)
            },
            _ => panic!()
        }
    }

    pub fn get_box_drop(&mut self, map_area: &MapArea, object: &MapObject) -> Option<ItemDropType> {
        self.box_table.get_drop(map_area, object, &mut self.rng)
    }
}


#[cfg(test)]
mod test {
    use super::*;
    use rand::seq::IteratorRandom;

    #[test]
    fn test_initializing_drop_table() {
        let mut rng = rand_chacha::ChaCha20Rng::from_entropy();
        let episode = vec![Episode::One, Episode::Two].into_iter().choose(&mut rng).unwrap();
        let difficulty = vec![Difficulty::Normal, Difficulty::Hard, Difficulty::VeryHard, Difficulty::Ultimate]
            .into_iter().choose(&mut rng).unwrap();
        let section_id = vec![SectionID::Viridia, SectionID::Greenill, SectionID::Skyly, SectionID::Bluefull, SectionID::Purplenum,
                              SectionID::Pinkal, SectionID::Redria, SectionID::Oran, SectionID::Yellowboze, SectionID::Whitill]
            .into_iter().choose(&mut rng).unwrap();
        DropTable::<rand_chacha::ChaCha20Rng>::new(episode, difficulty, section_id);
    }
}