// Orders: "attack" on an enemy unit or tower sends the fighting creatures nearby at it; on open
// ground it sets an attack marker (a sword) - the ready creatures share out over all swords and
// fight where they stand. "Guard" sets a guard marker (a shield) that three creatures hold. Up to
// eight of each; a right click on a marker removes it (elsewhere: the guards stand down).

use crate::game::*;
use crate::map::*;

const ORDER_RADIUS: f32 = 18.0;
const GUARDS: usize = 3;
pub const MAX_MARKS: usize = 8;

fn ready(e: &Ent) -> bool {
    e.alive && !e.held && e.creature() && !matches!(e.job, Job::Leave | Job::Register | Job::MakeBed(_)) && e.hp > e.max_hp * 0.25
}

impl Game {
    // attack: the enemy (unit, or tower) at (wx, wy)
    pub fn order_attack(&mut self, picked: Option<usize>, wx: f32, wy: f32) {
        let unit = picked.filter(|&j| j < self.ents.len() && self.is_hostile(&self.ents[j])).or_else(|| {
            self.ents.iter().position(|e| self.is_hostile(e) && (e.x - wx).powi(2) + (e.y - wy).powi(2) < 1.5 * 1.5)
        });
        let tower = if unit.is_none() {
            self.towers.iter().find(|t| t.hero && (t.pos().0 - wx).powi(2) + (t.pos().1 - wy).powi(2) < 1.2 * 1.2).map(|t| (t.id, t.pos()))
        } else {
            None
        };
        let (tx, ty) = match (unit, tower) {
            (Some(j), _) => (self.ents[j].x, self.ents[j].y),
            (None, Some((_, p))) => p,
            _ => {
                // open ground: an attack marker
                self.place_mark(wx.floor() as i32, wy.floor() as i32, true);
                return;
            }
        };
        let mut n = 0;
        for e in self.ents.iter_mut().filter(|e| ready(e) && (e.x - tx).powi(2) + (e.y - ty).powi(2) < ORDER_RADIUS * ORDER_RADIUS) {
            e.job = match (unit, tower) {
                (Some(_), _) => Job::Attack(0),
                (None, Some((id, _))) => Job::AttackTower(id),
                _ => continue,
            };
            e.path.clear();
            e.repath = 0.0;
            n += 1;
        }
        if let Some(j) = unit {
            let id = self.ents[j].id;
            for e in self.ents.iter_mut() {
                if e.job == Job::Attack(0) {
                    e.job = Job::Attack(id);
                }
            }
        }
        if n == 0 {
            self.hint(31, "hint.order_nobody");
            return;
        }
        self.fx(7, tx, ty, 0.0, 0.0, 0.6, 0xff3040ff);
        self.sfx_ui(Sfx::FlagSet);
        self.msg("msg.order_attack", vec![n.to_string()]);
    }

    // guard: a guard marker at (x, y) (three creatures hold it, see update_marks)
    pub fn order_guard(&mut self, x: i32, y: i32) {
        self.place_mark(x, y, false);
    }

    // a sword (attack) or shield (guard) marker on tile (x, y)
    pub fn place_mark(&mut self, x: i32, y: i32, attack: bool) {
        if !inb(x, y) {
            return;
        }
        let i = idx(x, y);
        let t = self.map.t[i];
        // a guard marker stands on own ground, an attack marker anywhere one can walk
        let ok = if attack { t.walkable() || t.bridge() } else { t.owner == self.me && t.walkable() };
        if !ok {
            self.hint(31, if attack { "hint.order_attack" } else { "hint.order_guard" });
            self.sfx_ui(Sfx::Error);
            return;
        }
        let marks = if attack { &self.attack_marks } else { &self.guard_marks };
        if marks.iter().any(|&m| {
            let (mx, my) = xy(m);
            (mx - x).abs() <= 1 && (my - y).abs() <= 1
        }) {
            return; // there is one already
        }
        if marks.len() >= MAX_MARKS {
            self.hint(31, "hint.marks_full");
            self.sfx_ui(Sfx::Error);
            return;
        }
        if attack {
            self.attack_marks.push(i);
        } else {
            self.guard_marks.push(i);
        }
        self.marks_t = 0.0; // creatures are sent at once
        self.fx(7, x as f32 + 0.5, y as f32 + 0.5, 0.0, 0.0, 0.6, if attack { 0xff3040ff } else { 0xff40d0ff });
        self.sfx_ui(Sfx::FlagSet);
        self.msg(if attack { "msg.mark_attack" } else { "msg.mark_guard" }, vec![]);
    }

    // a right click with an order tool: the marker there goes (its creatures are free again);
    // without a marker there the guards stand down
    pub fn unmark(&mut self, wx: f32, wy: f32) {
        let near = |m: &usize| {
            let (mx, my) = xy(*m);
            (mx as f32 + 0.5 - wx).powi(2) + (my as f32 + 0.5 - wy).powi(2) < 1.6 * 1.6
        };
        if let Some(k) = self.attack_marks.iter().position(near) {
            let m = self.attack_marks.remove(k);
            for e in self.ents.iter_mut().filter(|e| e.job == Job::March(m)) {
                e.job = Job::None;
                e.path.clear();
            }
        } else if let Some(k) = self.guard_marks.iter().position(near) {
            let m = self.guard_marks.remove(k);
            for j in 0..self.ents.len() {
                if let Job::Guard(spot) = self.ents[j].job {
                    if guard_of(m, spot) && self.ents[j].creature() {
                        let me = self.ents[j].id + 1;
                        self.unreserve(me);
                        self.ents[j].job = Job::None;
                    }
                }
            }
        } else {
            self.cancel_orders();
            return;
        }
        self.msg("msg.mark_removed", vec![]);
        self.sfx_ui(Sfx::Click);
    }

    // every second: three creatures for every shield, the ready ones shared out over the swords
    pub(crate) fn update_marks(&mut self, dt: f32) {
        self.marks_t -= dt;
        if self.marks_t > 0.0 || (self.guard_marks.is_empty() && self.attack_marks.is_empty()) {
            return;
        }
        self.marks_t = 1.0;
        // markers on ground that is gone (dug in, lost) go
        let me = self.me;
        let map = &self.map;
        self.guard_marks.retain(|&m| map.t[m].owner == me && map.t[m].walkable());
        self.attack_marks.retain(|&m| map.t[m].walkable() || map.t[m].bridge());
        // shields
        for m in self.guard_marks.clone() {
            let have = self.ents.iter().filter(|e| e.alive && e.creature() && matches!(e.job, Job::Guard(s) if guard_of(m, s))).count();
            for _ in have..GUARDS {
                if !self.send_guard(m) {
                    break;
                }
            }
        }
        // swords: every ready creature that is free goes to the nearest sword with room
        if self.attack_marks.is_empty() {
            return;
        }
        let free: Vec<usize> = (0..self.ents.len())
            .filter(|&j| {
                let e = &self.ents[j];
                ready(e) && e.hp > e.max_hp * 0.5 && e.energy > 0.15 && matches!(e.job, Job::None | Job::Wander | Job::Train(_) | Job::Study(_) | Job::March(_))
            })
            .collect();
        let cap = free.len().div_ceil(self.attack_marks.len()).max(1);
        let mut count: Vec<usize> = self.attack_marks.iter().map(|&m| self.ents.iter().filter(|e| e.alive && e.job == Job::March(m)).count()).collect();
        for j in free {
            if matches!(self.ents[j].job, Job::March(_)) {
                continue;
            }
            let (ex, ey) = (self.ents[j].x, self.ents[j].y);
            let best = (0..self.attack_marks.len()).filter(|&k| count[k] < cap).min_by(|&a, &b| {
                let d = |k: usize| {
                    let (mx, my) = xy(self.attack_marks[k]);
                    (mx as f32 + 0.5 - ex).powi(2) + (my as f32 + 0.5 - ey).powi(2)
                };
                d(a).partial_cmp(&d(b)).unwrap_or(std::cmp::Ordering::Equal)
            });
            let Some(k) = best else { break };
            count[k] += 1;
            let mark = self.attack_marks[k];
            let me = self.ents[j].id + 1;
            self.unreserve(me);
            let e = &mut self.ents[j];
            e.job = Job::March(mark);
            e.path.clear();
            e.repath = 0.0;
        }
    }

    // the nearest free creature takes a free spot next to shield m
    fn send_guard(&mut self, m: usize) -> bool {
        let (x, y) = xy(m);
        let spot = (-2..=2).flat_map(|dy| (-2..=2).map(move |dx| (dx, dy))).filter(|&(dx, dy)| inb(x + dx, y + dy)).map(|(dx, dy)| idx(x + dx, y + dy)).filter(|&j| {
            let t = &self.map.t[j];
            t.walkable() && t.owner == self.me && t.reserved == 0 && !self.ents.iter().any(|e| e.job == Job::Guard(j))
        }).min_by_key(|&j| {
            let (sx, sy) = xy(j);
            (sx - x).pow(2) + (sy - y).pow(2)
        });
        let Some(spot) = spot else { return false };
        let (fx, fy) = (x as f32 + 0.5, y as f32 + 0.5);
        let cand = (0..self.ents.len()).filter(|&j| ready(&self.ents[j]) && !matches!(self.ents[j].job, Job::Attack(_) | Job::Guard(_) | Job::March(_) | Job::Rally)).min_by(|&a, &b| {
            let d = |j: usize| (self.ents[j].x - fx).powi(2) + (self.ents[j].y - fy).powi(2);
            d(a).partial_cmp(&d(b)).unwrap_or(std::cmp::Ordering::Equal)
        });
        let Some(j) = cand else { return false };
        let Some(p) = self.map.creature_path(flies(self.ents[j].kind), self.ents[j].tile(), spot) else { return false };
        let me = self.ents[j].id + 1;
        self.unreserve(me);
        self.map.t[spot].reserved = me;
        let e = &mut self.ents[j];
        e.job = Job::Guard(spot);
        e.path = p;
        e.timer = 1.0e9; // until the marker goes
        true
    }

    // the old one-off guard order in a room (kept for scripts and tests)
    #[allow(dead_code)]
    pub fn order_guard_room(&mut self, x: i32, y: i32) {
        if !inb(x, y) {
            return;
        }
        let i = idx(x, y);
        let kind = self.map.t[i].kind;
        if self.map.t[i].owner != self.me || room_index(kind).is_none() && kind != Kind::Floor {
            self.hint(31, "hint.order_guard");
            self.sfx_ui(Sfx::Error);
            return;
        }
        // the spots: tiles of the same room (or floor) around the click
        let mut spots: Vec<usize> = Vec::new();
        for dy in -3..=3 {
            for dx in -3..=3 {
                if let Some(t) = self.map.get(x + dx, y + dy) {
                    let j = idx(x + dx, y + dy);
                    if t.kind == kind && t.owner == self.me && t.reserved == 0 && !self.ents.iter().any(|e| e.job == Job::Guard(j)) {
                        spots.push(j);
                    }
                }
            }
        }
        spots.sort_by_key(|&j| {
            let (sx, sy) = xy(j);
            (sx - x).pow(2) + (sy - y).pow(2)
        });
        let (fx, fy) = (x as f32 + 0.5, y as f32 + 0.5);
        let mut cands: Vec<usize> = (0..self.ents.len()).filter(|&j| ready(&self.ents[j]) && !matches!(self.ents[j].job, Job::Attack(_) | Job::Guard(_))).collect();
        cands.sort_by(|&a, &b| {
            let da = (self.ents[a].x - fx).powi(2) + (self.ents[a].y - fy).powi(2);
            let db = (self.ents[b].x - fx).powi(2) + (self.ents[b].y - fy).powi(2);
            da.partial_cmp(&db).unwrap_or(std::cmp::Ordering::Equal)
        });
        let mut n = 0;
        for (&j, &spot) in cands.iter().zip(spots.iter()).take(GUARDS) {
            let cur = self.ents[j].tile();
            let Some(p) = self.map.creature_path(flies(self.ents[j].kind), cur, spot) else { continue };
            let me = self.ents[j].id + 1;
            self.unreserve(me);
            self.map.t[spot].reserved = me;
            let e = &mut self.ents[j];
            e.job = Job::Guard(spot);
            e.path = p;
            e.timer = 120.0;
            n += 1;
        }
        if n == 0 {
            self.hint(31, "hint.order_nobody");
            return;
        }
        self.fx(8, fx, fy, 0.0, 0.0, 0.6, 0xff40d0ff);
        self.sfx_ui(Sfx::FlagSet);
        self.msg("msg.order_guard", vec![n.to_string()]);
    }

    // right click with an order tool: everybody stands down
    pub fn cancel_orders(&mut self) {
        let mut n = 0;
        for k in 0..self.ents.len() {
            if matches!(self.ents[k].job, Job::Guard(_)) && self.ents[k].creature() {
                let me = self.ents[k].id + 1;
                self.unreserve(me);
                self.ents[k].job = Job::None;
                n += 1;
            }
        }
        if n > 0 {
            self.msg("msg.orders_cancelled", vec![]);
            self.sfx_ui(Sfx::Click);
        }
    }
}

// is guard spot s next to shield m?
fn guard_of(m: usize, s: usize) -> bool {
    let (mx, my) = xy(m);
    let (sx, sy) = xy(s);
    (mx - sx).abs() <= 2 && (my - sy).abs() <= 2
}

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

    #[test]
    fn creatures_follow_attack_and_guard_orders() {
        let mut g = Game::new(14, 64, 64);
        let (cx, cy) = g.map.core;
        let ids: Vec<u32> = (0..4).map(|k| g.spawn(EK::Ogre, false, cx as f32 - 0.5, cy as f32 + 0.5 + k as f32 * 0.3, 2)).collect();
        let knight = g.spawn(EK::Knight, true, cx as f32 + 2.5, cy as f32 - 1.5, 1);
        let j = g.find(knight).unwrap();
        g.order_attack(Some(j), 0.0, 0.0);
        assert!(ids.iter().all(|&id| g.ents[g.find(id).unwrap()].job == Job::Attack(knight)));
        // guard the treasury ring around the core
        for &id in &ids {
            let j = g.find(id).unwrap();
            g.ents[j].job = Job::None;
        }
        g.order_guard_room(cx - 1, cy - 1);
        let guards = g.ents.iter().filter(|e| matches!(e.job, Job::Guard(_))).count();
        assert_eq!(guards, 3);
        g.cancel_orders();
        assert_eq!(g.ents.iter().filter(|e| matches!(e.job, Job::Guard(_))).count(), 0);
    }

    #[test]
    fn shields_are_held_and_swords_share_the_creatures() {
        let mut g = Game::new(14, 64, 64);
        let (cx, cy) = g.map.core;
        for y in cy - 6..=cy + 8 {
            for x in cx - 6..=cx + 10 {
                let t = &mut g.map.t[idx(x, y)];
                if t.kind != Kind::Core {
                    t.kind = Kind::Floor;
                    t.owner = Owner::Player;
                }
            }
        }
        let ids: Vec<u32> = (0..6).map(|k| g.spawn(EK::Ogre, false, cx as f32 - 2.5, cy as f32 + 0.5 + k as f32 * 0.3, 2)).collect();
        for &id in &ids {
            let j = g.find(id).unwrap();
            g.ents[j].settled = true;
            g.ents[j].job = Job::None;
        }
        g.order_guard(cx + 5, cy + 5);
        g.update_marks(1.0);
        let guards = g.ents.iter().filter(|e| matches!(e.job, Job::Guard(_))).count();
        assert_eq!(guards, 3, "three hold the shield");
        g.place_mark(cx + 8, cy - 4, true);
        g.place_mark(cx - 4, cy - 5, true);
        g.update_marks(1.0);
        let a = g.ents.iter().filter(|e| e.job == Job::March(g.attack_marks[0])).count();
        let b = g.ents.iter().filter(|e| e.job == Job::March(g.attack_marks[1])).count();
        assert!(a + b == 3 && a.abs_diff(b) <= 1, "{} and {}", a, b);
        // a right click on a sword frees its creatures
        let (sx, sy) = xy(g.attack_marks[0]);
        g.unmark(sx as f32 + 0.5, sy as f32 + 0.5);
        assert_eq!(g.attack_marks.len(), 1);
        assert!(!g.ents.iter().any(|e| e.job == Job::March(idx(sx, sy))));
    }
}