// Rival dungeon masters (simplified): a dungeon around their own soul core that grows over
// time, creatures that appear there, guard it and attack in groups - the player, the other
// master or the humans. A master whose core falls is out; its ground becomes free.

use crate::game::*;
use crate::map::*;
use serde::{Deserialize, Serialize};

pub const RIVAL_CORE_HP: f32 = 2000.0;

#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct Rival {
    pub side: u8,        // 2 (green) or 3 (blue)
    pub core: (i32, i32), // top-left corner of the 3x3 core
    pub hp: f32,
    pub alive: bool,
    pub radius: i32, // size of the dungeon around the core
    pub grow_t: f32,
    pub spawn_t: f32,
    pub attack_t: f32,
    pub difficulty: u8, // 0 easy, 1 medium, 2 hard
    pub power: f32,     // grows with the time: level of the new creatures
}

struct Pace {
    spawn: f32,      // seconds between new creatures
    grow: f32,       // seconds between growth steps
    attack: f32,     // seconds between attacks
    cap: usize,      // most creatures at a time
    max_radius: i32, // largest dungeon
    power: f32,      // levels per minute
}

fn pace(d: u8) -> Pace {
    match d {
        0 => Pace { spawn: 55.0, grow: 45.0, attack: 330.0, cap: 6, max_radius: 8, power: 0.25 },
        2 => Pace { spawn: 26.0, grow: 22.0, attack: 170.0, cap: 13, max_radius: 13, power: 0.6 },
        _ => Pace { spawn: 38.0, grow: 30.0, attack: 240.0, cap: 9, max_radius: 11, power: 0.4 },
    }
}

impl Rival {
    pub fn centre(&self) -> (f32, f32) {
        (self.core.0 as f32 + 1.5, self.core.1 as f32 + 1.5)
    }
}

impl Game {
    // Free game: one opponent per map up to 128 x 128 tiles, two on bigger maps; with a chance of
    // one in two one of them is the humans' gate instead of a rival master
    pub fn new_free(seed: u32, w: usize, h: usize, difficulty: u8) -> Game {
        let opponents = if w * h > 128 * 128 { 2 } else { 1 };
        let mut rng = Rng((seed ^ 0x9e37_79b9) | 1);
        for _ in 0..5 {
            rng.next();
        }
        let humans = rng.f() < 0.5;
        let rivals = if humans { opponents - 1 } else { opponents };
        let opts = GenOpts { gate: humans, ..GenOpts::default() };
        let map = Map::generate_with(seed, w, h, &opts);
        let mut g = Game::from_map(map, seed);
        g.gate_on = humans;
        if humans {
            let (cx, cy) = g.map.core;
            let (gx, gy) = g.map.gate;
            let dist = ((gx - cx).abs() + (gy - cy).abs()) as f32;
            g.wave_timer = FIRST_WAVE + ((dist - 45.0) * 1.5).clamp(0.0, 300.0);
        } else {
            g.gate_hp = 0.0;
        }
        g.guard_treasures();
        // the rival dungeons on the far side, away from the gate
        let (wi, hi) = (g.map.w as i32, g.map.h as i32);
        let x = wi - 14;
        let spots: Vec<(i32, i32)> = match (rivals, humans) {
            (1, false) => vec![(x, hi / 2)],
            (1, true) => vec![(x, if g.map.gate.1 < hi / 2 { hi * 3 / 4 } else { hi / 4 })],
            (2, _) => vec![(x, hi / 4), (x, hi * 3 / 4)],
            _ => Vec::new(),
        };
        for (k, &(rx, ry)) in spots.iter().enumerate() {
            g.add_rival(2 + k as u8, rx, ry.clamp(8, hi - 9), difficulty);
        }
        g.place_all_torches();
        g.msg("msg.welcome1", vec![]);
        g.msg("msg.welcome2", vec![]);
        g.msg(if rivals == 0 { "msg.welcome_humans" } else if humans { "msg.welcome_both" } else { "msg.welcome_rivals" }, vec![rivals.to_string()]);
        g.init_research(None);
        g.init_fog();
        g.place_dwarf_caves(seed);
        g
    }

    pub fn rival_alive(&self, side: u8) -> bool {
        self.rivals.iter().any(|r| r.side == side && r.alive)
    }

    // sets up a rival dungeon around (cx, cy)
    pub fn add_rival(&mut self, side: u8, cx: i32, cy: i32, difficulty: u8) {
        let owner = Owner::of_side(side);
        let core = (cx - 1, cy - 1);
        let r = 4;
        for y in cy - r..=cy + r {
            for x in cx - r..=cx + r {
                if !inb(x, y) || x < 2 || y < 2 || x >= mw() as i32 - 2 || y >= mh() as i32 - 2 {
                    continue;
                }
                let t = &mut self.map.t[idx(x, y)];
                if matches!(t.kind, Kind::Portal | Kind::Gate | Kind::Core) {
                    continue; // portals and other cores stay
                }
                t.kind = Kind::Floor;
                t.owner = owner;
                t.gold = 0;
                t.marked = false;
                t.reinforced = false;
            }
        }
        for y in 0..3 {
            for x in 0..3 {
                let t = &mut self.map.t[idx(core.0 + x, core.1 + y)];
                t.kind = Kind::Core;
                t.owner = owner;
            }
        }
        // a lair and a treasury (the player can take it)
        for y in cy - 3..=cy + 3 {
            let t = &mut self.map.t[idx(cx - 3, y)];
            t.kind = Kind::Lair;
        }
        for y in cy - 1..=cy + 1 {
            let t = &mut self.map.t[idx(cx + 3, y)];
            t.kind = Kind::Treasury;
            t.gold = 300;
            t.res = 0;
        }
        self.rivals.push(Rival { side, core, hp: RIVAL_CORE_HP, alive: true, radius: r, grow_t: 20.0, spawn_t: 5.0, attack_t: pace(difficulty).attack, difficulty, power: 0.0 });
        for k in 0..3 {
            self.spawn_rival_unit(side, EK::Kobold, 1, k as f32);
        }
    }

    fn spawn_rival_unit(&mut self, side: u8, kind: EK, level: u32, k: f32) {
        let Some(rv) = self.rivals.iter().find(|r| r.side == side) else { return };
        let (cx, cy) = rv.centre();
        let a = k * 1.7 + self.rng.f() * 2.0;
        let (x, y) = (cx + a.cos() * 2.4, cy + a.sin() * 2.4);
        let id = self.spawn(kind, false, x, y, level);
        if let Some(e) = self.ents.iter_mut().find(|e| e.id == id) {
            e.side = side;
            e.home = Some((cx, cy));
        }
    }

    pub fn update_rivals(&mut self, dt: f32) {
        for k in 0..self.rivals.len() {
            if !self.rivals[k].alive {
                continue;
            }
            let p = pace(self.rivals[k].difficulty);
            let side = self.rivals[k].side;
            {
                let r = &mut self.rivals[k];
                r.power += dt / 60.0 * p.power;
                r.grow_t -= dt;
                r.spawn_t -= dt;
                r.attack_t -= dt;
            }
            // growth: one more ring of ground (no imps needed)
            if self.rivals[k].grow_t <= 0.0 {
                self.rivals[k].grow_t = p.grow * (0.8 + self.rng.f() * 0.4);
                if self.rivals[k].radius < p.max_radius {
                    self.rivals[k].radius += 1;
                    self.rival_grow(k);
                }
            }
            // new creatures
            let units = self.ents.iter().filter(|e| e.alive && e.side == side && !e.hero).count();
            if self.rivals[k].spawn_t <= 0.0 {
                self.rivals[k].spawn_t = p.spawn * (0.8 + self.rng.f() * 0.4);
                if units < p.cap {
                    let power = self.rivals[k].power;
                    let mut pool = vec![EK::Kobold, EK::Spider];
                    if power >= 1.5 {
                        pool.extend([EK::Mage, EK::Ogre]);
                    }
                    if power >= 3.0 {
                        pool.push(EK::Gargoyle);
                    }
                    let kind = pool[(self.rng.next() as usize) % pool.len()];
                    let level = (1.0 + power) as u32;
                    self.spawn_rival_unit(side, kind, level.clamp(1, 10), units as f32);
                }
            }
            // attack: about two thirds of the creatures march on an enemy
            if self.rivals[k].attack_t <= 0.0 {
                self.rivals[k].attack_t = p.attack * (0.8 + self.rng.f() * 0.4);
                let mut targets: Vec<(u8, u32)> = vec![(0, 3)];
                for o in &self.rivals {
                    if o.alive && o.side != side {
                        targets.push((o.side, 1));
                    }
                }
                if self.has_gate() && self.gate_hp > 0.0 {
                    targets.push((1, 1));
                }
                let total: u32 = targets.iter().map(|t| t.1).sum();
                let mut r = self.rng.next() % total;
                let mut target = 0;
                for (s, w) in targets {
                    if r < w {
                        target = s;
                        break;
                    }
                    r -= w;
                }
                let mut n = 0;
                for e in self.ents.iter_mut() {
                    if e.alive && !e.hero && e.side == side && e.target.is_none() && n * 3 < units * 2 {
                        e.target = Some(target);
                        e.path.clear();
                        n += 1;
                    }
                }
                if n > 0 && target == 0 {
                    self.msg(if side == 2 { "msg.rival1_attack" } else { "msg.rival2_attack" }, vec![n.to_string()]);
                    self.sfx_ui(Sfx::WaveAlarm);
                }
            }
        }
    }

    // a ring of earth around the rival dungeon becomes its ground
    fn rival_grow(&mut self, k: usize) {
        let rv = self.rivals[k].clone();
        let owner = Owner::of_side(rv.side);
        let (cx, cy) = (rv.core.0 + 1, rv.core.1 + 1);
        let r = rv.radius;
        for y in cy - r..=cy + r {
            for x in cx - r..=cx + r {
                if (x - cx).abs() != r && (y - cy).abs() != r {
                    continue;
                }
                if !inb(x, y) || x < 2 || y < 2 || x >= mw() as i32 - 2 || y >= mh() as i32 - 2 {
                    continue;
                }
                let t = self.map.t[idx(x, y)];
                let free = matches!(t.kind, Kind::Earth | Kind::Floor) && !t.reinforced && t.owner == Owner::None;
                let touches = DIR4.iter().any(|&(dx, dy)| self.map.get(x + dx, y + dy).map_or(false, |n| n.owner == owner && n.walkable()));
                if free && touches {
                    let tl = &mut self.map.t[idx(x, y)];
                    tl.kind = Kind::Floor;
                    tl.owner = owner;
                    tl.gold = 0;
                    tl.marked = false;
                }
            }
        }
    }

    // damage to the core of a rival master
    pub fn rival_core_hit(&mut self, side: u8, dmg: f32) {
        let Some(k) = self.rivals.iter().position(|r| r.side == side && r.alive) else { return };
        self.rivals[k].hp -= dmg;
        let (x, y) = self.rivals[k].centre();
        self.fx(2, x, y, 0.0, 0.0, 0.3, 0xff4040ff);
        self.sfx(Sfx::CoreHit, x, y);
        if self.rivals[k].hp <= 0.0 {
            self.eliminate_rival(k);
        }
    }

    pub(crate) fn eliminate_rival(&mut self, k: usize) {
        let side = self.rivals[k].side;
        let owner = Owner::of_side(side);
        self.rivals[k].alive = false;
        self.rivals[k].hp = 0.0;
        let (x, y) = self.rivals[k].centre();
        self.fx(1, x, y, 0.0, 0.0, 1.0, 0xffffffff);
        self.sfx(Sfx::Victory, x, y);
        self.msg(if side == 2 { "msg.rival1_out" } else { "msg.rival2_out" }, vec![]);
        // its creatures scatter and vanish, its ground is free
        for e in self.ents.iter_mut() {
            if e.alive && !e.hero && e.side == side {
                e.alive = false;
            }
        }
        for t in self.map.t.iter_mut() {
            if t.owner == owner {
                if t.kind == Kind::Core {
                    t.kind = Kind::Floor;
                }
                t.owner = Owner::None;
            }
        }
    }

    // where an attacker of `side`'s enemy is heading: the core (or gate) of the target side
    fn target_core_adjacent(&self, i: usize, target: u8) -> bool {
        match target {
            1 => {
                let (x, y) = xy(i);
                DIR4.iter().any(|&(dx, dy)| self.map.get(x + dx, y + dy).map_or(false, |t| t.kind == Kind::Gate))
            }
            s => self.map.adj_core_of(i, Owner::of_side(s)),
        }
    }

    fn target_alive(&self, target: u8) -> bool {
        match target {
            0 => self.core_hp > 0.0,
            1 => self.has_gate() && self.gate_hp > 0.0,
            s => self.rival_alive(s),
        }
    }

    // hit the core (or gate) of the target side
    pub fn hit_target_core(&mut self, e: &mut Ent, target: u8) {
        let dmg = e.atk();
        e.cd = st(e.kind).interval;
        match target {
            0 => {
                self.core_hp -= dmg;
                let (cx, cy) = self.map.core;
                self.fx(2, (e.x + cx as f32 + 1.5) * 0.5, (e.y + cy as f32 + 1.5) * 0.5, 0.0, 0.0, 0.3, 0xff4040ff);
                self.sfx(Sfx::CoreHit, e.x, e.y);
                self.hint(6, "hint.core_attacked");
            }
            1 => {
                self.gate_hp -= dmg;
                self.gate_hit_t = self.time;
                let (gx, gy) = self.gate_center();
                self.sfx(Sfx::GateHit, gx, gy);
            }
            s => self.rival_core_hit(s, dmg),
        }
    }

    // the march of an attacker on a core; false = no target (any more)
    pub fn march_on(&mut self, e: &mut Ent, dt: f32) -> bool {
        let Some(target) = e.target else { return false };
        if !self.target_alive(target) || target == e.side() {
            e.target = None;
            return false;
        }
        let cur = e.tile();
        if e.path.is_empty() && self.target_core_adjacent(cur, target) {
            e.working = true;
            if e.cd <= 0.0 {
                self.hit_target_core(e, target);
            }
            return true;
        }
        if e.path.is_empty() && e.repath <= 0.0 {
            e.repath = 1.5;
            // attackers dig their way like heroes; the player's creatures only walk
            let goal = |i: usize| self.target_core_adjacent(i, target);
            let found = if e.side() == 0 { self.map.search(cur, self.map.walk_cost(), goal, true) } else { self.map.search(cur, self.map.hero_cost(), goal, true) };
            match found {
                Some(p) => e.path = p,
                None => {
                    e.target = None;
                    return false;
                }
            }
        }
        self.step_path(e, dt);
        true
    }

    // units of a rival master: fight enemies nearby, march when sent, otherwise guard home
    pub fn rival_ai(&mut self, e: &mut Ent, dt: f32) {
        if e.think <= 0.0 {
            e.think = 0.5;
            if !matches!(e.job, Job::Attack(_)) {
                let radius = if e.target.is_some() { 6.0 } else { 8.0 };
                if let Some(id) = self.nearest_enemy(e, radius) {
                    e.job = Job::Attack(id);
                    e.path.clear();
                    e.repath = 0.0;
                }
            }
        }
        if let Job::Attack(id) = e.job {
            let (hx, hy) = e.home.unwrap_or((e.x, e.y));
            let far = e.target.is_none() && (e.x - hx).powi(2) + (e.y - hy).powi(2) > 15.0 * 15.0;
            if !far && self.attack_job(e, id, dt) {
                return;
            }
            e.job = Job::None;
            e.path.clear();
        }
        if self.march_on(e, dt) {
            return;
        }
        // guard the own dungeon
        let (hx, hy) = e.home.unwrap_or((e.x, e.y));
        let d2 = (e.x - hx).powi(2) + (e.y - hy).powi(2);
        if e.path.is_empty() && e.repath <= 0.0 {
            e.repath = 3.0 + self.rng.f() * 3.0;
            let (tx, ty) = if d2 > 36.0 { (hx, hy) } else { (hx + self.rng.f() * 8.0 - 4.0, hy + self.rng.f() * 8.0 - 4.0) };
            if self.map.walk(tx as i32, ty as i32) {
                if let Some(p) = self.map.path_to(e.tile(), idx(tx as i32, ty as i32)) {
                    e.path = p;
                }
            }
        }
        self.step_path(e, dt);
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn free_games_have_one_or_two_opponents() {
        for seed in 1..=12u32 {
            for &(w, h) in &[(64usize, 64usize), (160, 160)] {
                let g = Game::new_free(seed, w, h, 1);
                let opponents = g.rivals.len() + g.gate_on as usize;
                assert_eq!(opponents, if w * h > 128 * 128 { 2 } else { 1 }, "seed {} {}x{}", seed, w, h);
                for r in &g.rivals {
                    let (cx, cy) = (r.core.0 + 1, r.core.1 + 1);
                    assert_eq!(g.map.t[idx(cx, cy)].kind, Kind::Core);
                    assert_eq!(g.map.t[idx(cx, cy)].owner, Owner::of_side(r.side));
                }
                // the player's core is untouched
                let (px, py) = g.map.core;
                assert_eq!(g.map.t[idx(px + 1, py + 1)].owner, Owner::Player);
            }
        }
    }

    // a free game with exactly one rival master and no gate
    fn rival_game(difficulty: u8) -> Game {
        (1..200u32).map(|s| Game::new_free(s, 64, 64, difficulty)).find(|g| g.rivals.len() == 1 && !g.gate_on).unwrap()
    }

    #[test]
    fn rival_grows_spawns_and_attacks() {
        let mut g = rival_game(2);
        let r0 = g.rivals[0].radius;
        let core0 = g.core_hp;
        let mut attacked = false;
        for _ in 0..(12 * 60 * 20) {
            g.update(0.05);
            attacked |= g.ents.iter().any(|e| e.rival() && e.target == Some(0));
            if g.core_hp < core0 - 50.0 {
                break;
            }
        }
        assert!(g.rivals[0].radius > r0, "the rival dungeon grows");
        assert!(attacked, "the rival sends creatures");
        assert!(g.core_hp < core0, "they reach the player's core");
    }

    #[test]
    fn beating_the_rival_wins_the_free_game() {
        let mut g = rival_game(1);
        let side = g.rivals[0].side;
        g.update(0.05);
        assert!(g.ents.iter().any(|e| e.side == side && e.alive));
        g.rival_core_hit(side, RIVAL_CORE_HP + 1.0);
        assert!(!g.rivals[0].alive);
        assert!(!g.ents.iter().any(|e| e.side == side && e.alive));
        assert!(!g.map.t.iter().any(|t| t.owner == Owner::of_side(side)));
        g.update(0.05);
        assert_eq!(g.state, 1, "all opponents down: victory");
    }

    #[test]
    fn humans_attack_rival_masters_too() {
        let mut g = (1..200u32).map(|s| Game::new_free(s, 160, 160, 1)).find(|g| g.rivals.len() == 1 && g.gate_on).unwrap();
        let side = g.rivals[0].side;
        let (rx, ry) = g.rivals[0].centre();
        for k in 0..4 {
            let id = g.spawn(EK::Knight, true, rx + 6.0 + k as f32 * 0.3, ry, 4);
            if let Some(e) = g.ents.iter_mut().find(|e| e.id == id) {
                e.target = Some(side);
            }
        }
        let hp0 = g.rivals[0].hp;
        let mut fought = false;
        for _ in 0..(120 * 20) {
            g.update(0.05);
            fought |= g.rivals[0].hp < hp0 || g.ents.iter().any(|e| e.rival() && e.hp < e.max_hp);
            if fought {
                break;
            }
        }
        assert!(fought, "heroes fight the rival master");
    }
}