use std::collections::HashMap;
use std::sync::Arc;
pub const SNAPSHOT_INTERVAL_TICKS: i32 = 20;
use std::time::Instant;
use logic::battle::{
    LogicGameMode, LogicGameObjectEntry, LogicVector2, BATTLE_TICKS_PER_SECOND, BATTLE_TYPE_PVP,
};
use logic::battle::{verify_snapshot, LogicBattleEvent};
use logic::SectorStateMessage;
use logic::{BattleEventMessage, LogicDataRef, LogicRandom};
use titan::LogicLong;
use service_rpc::{AccountRef, WireMessage};
use tokio::sync::Mutex;
pub struct BattleSession {
    mode: LogicGameMode,
    tick: i32,
    queued: Vec<(i32, Vec<LogicGameObjectEntry>)>,
    outbound: Vec<WireMessage>,
    started_at: Instant,
    random: LogicRandom,
    taunts: Vec<LogicDataRef>,
    next_bot_emote: i32,
    next_snapshot: i32,
    next_bot_play: i32,
    pending_bot_play: Option<(LogicDataRef, LogicVector2, i32)>,
}
impl BattleSession {
    pub fn new(mode: LogicGameMode, taunts: Vec<LogicDataRef>) -> Self {
        let mut random = LogicRandom::new(mode.random_seed);
        let next_bot_emote = Self::roll_emote_tick(&mut random, 0);
        Self {
            mode,
            tick: 0,
            queued: Vec::new(),
            outbound: Vec::new(),
            started_at: Instant::now(),
            random,
            taunts,
            next_bot_emote,
            next_snapshot: SNAPSHOT_INTERVAL_TICKS,
            next_bot_play: 0,
            pending_bot_play: None,
        }
    }
    pub fn take_bot_play(&mut self) -> Option<(LogicDataRef, LogicVector2, i32)> {
        self.pending_bot_play.take()
    }
    pub fn bot_play(&mut self) -> Option<(LogicDataRef, LogicVector2, i32)> {
        let deck = self.mode.battle.decks.get(1)?.as_ref()?;
        let filled: Vec<LogicDataRef> = deck
            .slots
            .iter()
            .flatten()
            .map(|spell| spell.data.clone())
            .collect();
        if filled.is_empty() {
            return None;
        }
        let card = filled
            .get(self.random.next(filled.len() as i32).max(0) as usize)?
            .clone();
        let towers: Vec<(i32, i32)> = self
            .mode
            .battle
            .objects
            .objects
            .iter()
            .filter(|entry| entry.owner_index() == crate::bot::BOT_OWNER_INDEX)
            .map(|entry| entry.position())
            .collect();
        let leader = self.mode.battle.leader(crate::bot::BOT_OWNER_INDEX as usize)?;
        let (king_x, king_y) = leader.position();
        let ahead = towers
            .iter()
            .map(|(_, y)| *y)
            .fold(king_y, |best, y| if (y - king_y).abs() > (best - king_y).abs() { y } else { best });
        let lane_x = towers
            .iter()
            .filter(|(_, y)| *y == ahead)
            .map(|(x, _)| *x)
            .collect::<Vec<_>>();
        let x = lane_x
            .get(self.random.next(lane_x.len().max(1) as i32).max(0) as usize)
            .copied()
            .unwrap_or(king_x);
        Some((card, LogicVector2::new(x, ahead), self.next_instance()))
    }
    pub fn pushes_snapshots(&self) -> bool {
        self.mode.battle.battle_type == BATTLE_TYPE_PVP
    }
    fn snapshot_message(&mut self) -> Option<WireMessage> {
        let snapshot = self.mode.snapshot().ok()?;
        let report = verify_snapshot(&snapshot);
        if !report.is_ok() {
            tracing::error!(
                bytes = snapshot.len(),
                trailing = report.trailing,
                error = report.error.as_deref().unwrap_or("-"),
                "the battle snapshot does not read back, not pushing it"
            );
            return None;
        }
        crate::wire::encode(&SectorStateMessage::new(snapshot)).ok()
    }
    fn roll_emote_tick(random: &mut LogicRandom, from: i32) -> i32 {
        let span = crate::bot::BOT_EMOTE_MAX_SECONDS - crate::bot::BOT_EMOTE_MIN_SECONDS;
        let seconds = crate::bot::BOT_EMOTE_MIN_SECONDS + random.next(span.max(1));
        from + seconds * BATTLE_TICKS_PER_SECOND
    }
    pub fn opponent_account(&self) -> LogicLong {
        self.mode
            .battle
            .account_ids
            .get(1)
            .copied()
            .unwrap_or_default()
    }
    pub fn bot_emote(&mut self) -> Option<LogicBattleEvent> {
        if self.taunts.is_empty() {
            return None;
        }
        let index = self.random.next(self.taunts.len() as i32).max(0) as usize;
        let taunt = self.taunts.get(index)?;
        let instance = taunt.global_id().map(|id| id.instance_id).unwrap_or(0);
        Some(LogicBattleEvent {
            event_type: 1,
            account_id: self.opponent_account(),
            ticks: vec![self.tick],
            coords: Vec::new(),
            params: vec![instance],
        })
    }
    pub fn elapsed_tick(&self) -> i32 {
        let millis = self.started_at.elapsed().as_millis() as i64;
        (millis * BATTLE_TICKS_PER_SECOND as i64 / 1000) as i32
    }
    pub fn advance_to_now(&mut self) {
        let tick = self.elapsed_tick();
        self.advance_to(tick);
    }
    pub fn push_outbound(&mut self, message: WireMessage) {
        self.outbound.push(message);
    }
    pub fn take_outbound(&mut self) -> Vec<WireMessage> {
        std::mem::take(&mut self.outbound)
    }
    pub fn mode(&self) -> &LogicGameMode {
        &self.mode
    }
    pub fn tick(&self) -> i32 {
        self.tick
    }
    pub fn seconds(&self) -> i32 {
        self.tick / BATTLE_TICKS_PER_SECOND
    }
    pub fn queue(&mut self, at_tick: i32, entries: Vec<LogicGameObjectEntry>) {
        if entries.is_empty() {
            return;
        }
        self.queued.push((at_tick.max(self.tick + 1), entries));
    }
    pub fn advance_to(&mut self, tick: i32) {
        while self.tick < tick {
            self.tick += 1;
            self.release_queued(self.tick);
            self.mode.battle.tick(self.tick);
            if self.pushes_snapshots() && self.tick >= self.next_snapshot {
                self.next_snapshot = self.tick + SNAPSHOT_INTERVAL_TICKS;
                if let Some(message) = self.snapshot_message() {
                    self.outbound.push(message);
                }
            }
            if self.tick >= self.next_bot_play {
                let span = crate::bot::BOT_PLAY_MAX_SECONDS - crate::bot::BOT_PLAY_MIN_SECONDS;
                let wait = crate::bot::BOT_PLAY_MIN_SECONDS + self.random.next(span.max(1));
                self.next_bot_play = self.tick + wait * BATTLE_TICKS_PER_SECOND;
                if let Some((card, position, instance)) = self.bot_play() {
                    self.pending_bot_play = Some((card, position, instance));
                }
            }
            if self.tick >= self.next_bot_emote {
                self.next_bot_emote = Self::roll_emote_tick(&mut self.random, self.tick);
                if let Some(event) = self.bot_emote() {
                    if let Ok(message) = crate::wire::encode(&BattleEventMessage::new(event)) {
                        self.outbound.push(message);
                    }
                }
            }
        }
        self.mode.time.tick = self.tick;
    }
    fn release_queued(&mut self, tick: i32) {
        let mut due = Vec::new();
        self.queued.retain(|(at, entries)| {
            if *at <= tick {
                due.extend(entries.iter().cloned());
                false
            } else {
                true
            }
        });
        for entry in due {
            self.mode.battle.objects.push(entry);
        }
    }
    pub fn is_finished(&self) -> bool {
        self.mode.battle.is_end_condition_matched(self.tick)
    }
    pub fn stars(&self) -> (i32, i32) {
        (self.mode.battle.stars(0), self.mode.battle.stars(1))
    }
    pub fn checksum(&self) -> Option<i32> {
        self.mode.calculate_checksum().ok()
    }
    pub fn towers_standing(&self) -> (usize, usize) {
        (
            self.mode.battle.leader_towers[0].len(),
            self.mode.battle.leader_towers[1].len(),
        )
    }
    pub fn owner_of(&self, account: LogicLong) -> Option<i32> {
        self.mode
            .battle
            .account_ids
            .iter()
            .position(|id| *id == account)
            .map(|index| index as i32)
    }
    pub fn next_instance(&self) -> i32 {
        self.mode
            .battle
            .objects
            .objects
            .iter()
            .filter_map(|entry| entry.global_id.0.map(|id| id.instance_id))
            .max()
            .map(|last| last + 1)
            .unwrap_or(0)
    }
    pub fn deck_card(&self, owner: i32, slot: i32) -> Option<LogicDataRef> {
        let deck = self.mode.battle.decks.get(owner.max(0) as usize)?.as_ref()?;
        let spell = deck.slots.get(slot.max(0) as usize)?.as_ref()?;
        Some(spell.data.clone())
    }
    pub fn push(&mut self, entry: LogicGameObjectEntry) {
        self.mode.battle.objects.push(entry);
    }
    pub fn object_count(&self) -> usize {
        self.mode.battle.objects.objects.len()
    }
}
#[derive(Default)]
pub struct BattleRegistry {
    sessions: Mutex<HashMap<AccountRef, Arc<Mutex<BattleSession>>>>,
}
impl BattleRegistry {
    pub async fn start(
        &self,
        players: &[AccountRef],
        mode: LogicGameMode,
        taunts: Vec<LogicDataRef>,
    ) {
        let session = Arc::new(Mutex::new(BattleSession::new(mode, taunts)));
        let mut sessions = self.sessions.lock().await;
        for account in players {
            sessions.insert(*account, Arc::clone(&session));
        }
    }
    async fn session(&self, account: AccountRef) -> Option<Arc<Mutex<BattleSession>>> {
        self.sessions.lock().await.get(&account).cloned()
    }
    pub async fn is_running(&self, account: AccountRef) -> bool {
        self.sessions.lock().await.contains_key(&account)
    }
    pub async fn finish(&self, account: AccountRef) -> Option<Arc<Mutex<BattleSession>>> {
        self.sessions.lock().await.remove(&account)
    }
    pub async fn tick<F>(&self, account: AccountRef, summon: F) -> Vec<WireMessage>
    where
        F: Fn(&LogicDataRef, LogicVector2, i32, i32) -> Vec<LogicGameObjectEntry>,
    {
        let Some(handle) = self.session(account).await else {
            return Vec::new();
        };
        let mut session = handle.lock().await;
        session.advance_to_now();
        if let Some((card, position, instance)) = session.take_bot_play() {
            let entries = summon(&card, position, crate::bot::BOT_OWNER_INDEX, instance);
            if !entries.is_empty() {
                tracing::debug!(card = %card, count = entries.len(), "the bot played a card");
                for entry in entries {
                    session.push(entry);
                }
            }
        }
        session.take_outbound()
    }
    pub async fn answer_emote(&self, account: AccountRef) {
        let Some(handle) = self.session(account).await else {
            return;
        };
        let mut session = handle.lock().await;
        let Some(event) = session.bot_emote() else {
            return;
        };
        if let Ok(message) = crate::wire::encode(&BattleEventMessage::new(event)) {
            session.push_outbound(message);
        }
    }
    pub async fn send(&self, account: AccountRef, message: WireMessage) {
        if let Some(handle) = self.session(account).await {
            handle.lock().await.push_outbound(message);
        }
    }
    pub async fn advance(&self, account: AccountRef, tick: i32) -> Option<BattleProgress> {
        let handle = self.session(account).await?;
        let mut session = handle.lock().await;
        session.advance_to(tick);
        Some(BattleProgress {
            seconds: session.seconds(),
            finished: session.is_finished(),
            stars: session.stars(),
            objects: session.object_count(),
            towers: session.towers_standing(),
            checksum: session.checksum(),
        })
    }
    pub async fn play<F>(
        &self,
        account: AccountRef,
        executor: LogicLong,
        slot: i32,
        position: logic::battle::LogicVector2,
        at_tick: i32,
        summon: F,
    ) -> usize
    where
        F: Fn(&LogicDataRef, logic::battle::LogicVector2, i32, i32) -> Vec<LogicGameObjectEntry>,
    {
        let Some(handle) = self.session(account).await else {
            return 0;
        };
        let mut session = handle.lock().await;
        let Some(owner) = session.owner_of(executor) else {
            return 0;
        };
        let Some(card) = session.deck_card(owner, slot) else {
            return 0;
        };
        let entries = summon(&card, position, owner, session.next_instance());
        let spawned = entries.len();
        session.queue(at_tick, entries);
        spawned
    }
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct BattleProgress {
    pub seconds: i32,
    pub finished: bool,
    pub stars: (i32, i32),
    pub objects: usize,
    pub towers: (usize, usize),
    pub checksum: Option<i32>,
}