// Multiplayer step C (client): the browser-side lobby and turn bridge.
//
// The WebSocket itself is opened by the browser plugin (`dc_ws_*` in www/dc_plugin.js). This module
// only speaks the relay protocol from server/src/netplay.rs, turns `Command`s into JSON and feeds the
// game with confirmed turns. It can also run without a socket in tests: requests go into `outbox`,
// server answers are put back with `feed`.

#![allow(dead_code)]

use crate::commands::Command;
use serde_json::{json, Value};
use std::collections::VecDeque;

const MAX_CHAT: usize = 80;

#[derive(Clone, Copy, PartialEq, Eq, Debug, Default)]
pub enum Phase {
    #[default]
    Offline,
    Lobby,
    InLobby,
    Playing,
    Closed,
}

#[derive(Clone, Debug, Default)]
pub struct SeatUi {
    pub side: u8,
    pub name: String,
    pub ready: bool,
    pub connected: bool,
    pub ai: bool,
}

#[derive(Clone, Debug, Default)]
pub struct RoomUi {
    pub code: String,
    pub players: usize,
    pub sides: Vec<u8>,
    pub started: bool,
    pub paused: bool,
}

#[derive(Clone, Debug, Default)]
pub struct MatchUi {
    pub phase: Phase,
    pub connected: bool,
    pub name: String,
    pub code: Option<String>,
    pub local_side: Option<u8>,
    pub ready: bool,
    pub is_host: bool,
    pub sides: Vec<u8>,
    pub seats: Vec<SeatUi>,
    pub ai: Vec<u8>,
    pub rooms: Vec<RoomUi>,
    pub started: bool,
    pub paused: bool,
    pub missing: bool,
    pub turn: u32,
    pub error: Option<String>,
    pub status: Option<String>,
    pub chat: Vec<(Option<u8>, String, String)>,
}

impl MatchUi {
    pub fn room_open(&self) -> bool {
        self.code.is_some() || !self.seats.is_empty()
    }
}

#[derive(Clone, Debug)]
pub struct StartInfo {
    pub seed: u32,
    pub map_w: usize,
    pub map_h: usize,
    pub difficulty: u8,
    pub sides: Vec<u8>,
    pub local_side: Option<u8>,
    pub mission: Option<usize>,
    pub ai: Vec<u8>,
}

#[derive(Clone, Debug, Default)]
struct SeatInfo {
    side: u8,
    name: String,
    ready: bool,
    connected: bool,
    ai: bool,
}

#[derive(Clone, Debug, Default)]
struct RoomInfo {
    code: String,
    sides: Vec<u8>,
    seats: Vec<SeatInfo>,
    ai: Vec<u8>,
    turn: u32,
    started: bool,
    paused: bool,
    missing: bool,
}

#[derive(Clone, Debug)]
pub struct MatchClient {
    pub name: String,
    pub connected: bool,
    pub outbox: VecDeque<String>,
    code: Option<String>,
    room: Option<RoomInfo>,
    rooms: Vec<RoomUi>,
    local_side: Option<u8>,
    error: Option<String>,
    status: Option<String>,
    chat: Vec<(Option<u8>, String, String)>,
    chat_seen: usize,
    start: Option<StartInfo>,
    turns: Vec<(u32, Vec<Command>, Vec<u8>)>,
    checks: Vec<(Option<u8>, u32, u64)>,
    pub ping_ms: f32,
    ping_seq: u64,
    ping_next: f64,
    ping_pending: Option<(u64, f64)>,
}

impl MatchClient {
    pub fn new() -> Self {
        MatchClient {
            name: "Guest".into(),
            connected: false,
            outbox: VecDeque::new(),
            code: None,
            room: None,
            rooms: Vec::new(),
            local_side: None,
            error: None,
            status: None,
            chat: Vec::new(),
            chat_seen: 0,
            start: None,
            turns: Vec::new(),
            checks: Vec::new(),
            ping_ms: 0.0,
            ping_seq: 0,
            ping_next: 0.0,
            ping_pending: None,
        }
    }

    pub fn phase(&self) -> Phase {
        if !self.connected {
            return Phase::Offline;
        }
        match &self.room {
            Some(r) if r.started => Phase::Playing,
            Some(_) => Phase::InLobby,
            None if self.error.is_some() || self.status.as_deref().map(|s| s != "offline").unwrap_or(false) => Phase::Closed,
            None => Phase::Lobby,
        }
    }

    pub fn on_connect(&mut self, name: &str) {
        self.connected = true;
        self.name = name.to_string();
        self.status = None;
        self.ping_ms = 0.0;
        self.ping_pending = None;
        self.ping_next = 0.0;
        self.rooms_request();
    }

    pub fn on_disconnect(&mut self) {
        self.connected = false;
        self.room = None;
        self.code = None;
        self.local_side = None;
        self.start = None;
        self.turns.clear();
        self.status = Some("offline".into());
        self.ping_ms = 0.0;
        self.ping_pending = None;
        self.ping_next = 0.0;
    }

    pub fn tick_ping(&mut self, now: f64) {
        if let Some((_, start)) = self.ping_pending {
            if now - start > 5.0 {
                self.ping_pending = None;
                self.ping_ms = 0.0;
            }
        }
        if !self.connected || self.ping_pending.is_some() || now < self.ping_next {
            return;
        }
        self.ping_seq = self.ping_seq.wrapping_add(1);
        self.outbox.push_back(json!({"t":"ping","c":self.ping_seq}).to_string());
        self.ping_pending = Some((self.ping_seq, now));
        self.ping_next = now + 2.0;
    }

    pub fn rooms_request(&mut self) {
        self.outbox.push_back(json!({"t":"rooms"}).to_string());
    }

    pub fn create(&mut self, sides: &[u8], map_w: usize, map_h: usize, difficulty: u8) {
        self.send_create(sides, map_w, map_h, difficulty, None);
    }

    pub fn create_coop(&mut self, mission: usize, sides: &[u8], map_w: usize, map_h: usize, difficulty: u8) {
        self.send_create(sides, map_w, map_h, difficulty, Some(mission));
    }

    fn send_create(&mut self, sides: &[u8], map_w: usize, map_h: usize, difficulty: u8, mission: Option<usize>) {
        if !self.connected {
            return;
        }
        self.error = None;
        self.status = None;
        self.chat.clear();
        self.chat_seen = 0;
        self.outbox.push_back(json!({"t":"create","sides":sides,"map_w":map_w,"map_h":map_h,"difficulty":difficulty,"mission":mission}).to_string());
    }

    pub fn join(&mut self, code: &str) {
        if !self.connected {
            return;
        }
        let code = code.trim().to_uppercase();
        if code.len() != 6 {
            self.error = Some("match code needs 6 characters".into());
            return;
        }
        self.error = None;
        self.status = None;
        self.chat.clear();
        self.chat_seen = 0;
        self.outbox.push_back(json!({"t":"join","code":code}).to_string());
    }

    pub fn take_side(&mut self, side: u8) {
        if !self.connected {
            return;
        }
        self.outbox.push_back(json!({"t":"take_side","side":side}).to_string());
    }

    pub fn set_ai(&mut self, side: u8, ai: bool) {
        if !self.connected {
            return;
        }
        self.outbox.push_back(json!({"t":"set_ai","side":side,"ai":ai}).to_string());
    }

    pub fn ready(&mut self, ready: bool) {
        if !self.connected {
            return;
        }
        self.outbox.push_back(json!({"t":"ready","ready":ready}).to_string());
    }

    pub fn start(&mut self) {
        if !self.connected {
            return;
        }
        self.outbox.push_back(json!({"t":"start"}).to_string());
    }

    pub fn resume(&mut self) {
        if !self.connected {
            return;
        }
        self.outbox.push_back(json!({"t":"resume"}).to_string());
    }

    pub fn abort(&mut self) {
        if !self.connected {
            return;
        }
        self.outbox.push_back(json!({"t":"abort"}).to_string());
    }

    pub fn leave(&mut self) {
        if !self.connected {
            return;
        }
        self.outbox.push_back(json!({"t":"leave"}).to_string());
    }

    pub fn chat(&mut self, text: &str, team: bool) {
        let text: String = text.trim().chars().take(MAX_CHAT).collect();
        if !self.connected || text.is_empty() {
            return;
        }
        let msg = if team { json!({"t":"chat","text":text,"channel":"team"}) } else { json!({"t":"chat","text":text,"channel":"all"}) };
        self.outbox.push_back(msg.to_string());
    }

    pub fn send_commands(&mut self, cmds: &[Command]) {
        if !self.connected || cmds.is_empty() {
            return;
        }
        self.outbox.push_back(json!({"t":"cmds","cmds":cmds}).to_string());
    }

    pub fn send_checksum(&mut self, turn: u32, sum: u64) {
        if !self.connected {
            return;
        }
        self.outbox.push_back(json!({"t":"sum","turn":turn,"sum":sum}).to_string());
    }

    pub fn feed(&mut self, text: &str) {
        self.feed_at(text, 0.0);
    }

    pub fn feed_at(&mut self, text: &str, now: f64) {
        let v: Value = match serde_json::from_str(text) {
            Ok(v) => v,
            Err(_) => return,
        };
        match v.get("t").and_then(|x| x.as_str()).unwrap_or("") {
            "hello" => {
                if let Some(n) = v.get("name").and_then(|x| x.as_str()) {
                    self.name = n.to_string();
                }
            }
            "pong" => {
                if let Some(c) = v.get("c").and_then(|x| x.as_u64()) {
                    if let Some((seq, start)) = self.ping_pending {
                        if seq == c {
                            self.ping_ms = ((now - start).max(0.0) * 1000.0) as f32;
                            self.ping_pending = None;
                        }
                    }
                }
            }
            "rooms" => self.parse_rooms(&v),
            "room" => self.parse_room(&v),
            "start" => self.parse_start(&v),
            "turn" => self.parse_turn(&v),
            "sum" => self.parse_sum(&v),
            "chat" => {
                let name = v.get("name").and_then(|x| x.as_str()).unwrap_or("?").to_string();
                let text = v.get("text").and_then(|x| x.as_str()).unwrap_or("").to_string();
                let side = v.get("side").and_then(|x| x.as_u64()).map(|x| x as u8);
                self.chat.push((side, name, text));
                while self.chat.len() > 40 {
                    self.chat.remove(0);
                    if self.chat_seen > 0 {
                        self.chat_seen -= 1;
                    }
                }
            }
            "closed" => {
                self.status = Some(v.get("why").and_then(|x| x.as_str()).unwrap_or("closed").to_string());
                self.room = None;
                self.code = None;
                self.local_side = None;
                self.start = None;
                self.turns.clear();
                self.chat.clear();
                self.chat_seen = 0;
            }
            "error" => {
                self.error = Some(v.get("why").and_then(|x| x.as_str()).unwrap_or("error").to_string());
            }
            _ => {}
        }
    }

    pub fn take_start(&mut self) -> Option<StartInfo> {
        self.start.take()
    }

    pub fn take_turns(&mut self) -> Vec<(u32, Vec<Command>, Vec<u8>)> {
        std::mem::take(&mut self.turns)
    }

    pub fn take_checks(&mut self) -> Vec<(Option<u8>, u32, u64)> {
        std::mem::take(&mut self.checks)
    }

    pub fn take_new_chat(&mut self) -> Vec<(Option<u8>, String, String)> {
        if self.chat_seen >= self.chat.len() {
            return Vec::new();
        }
        let out = self.chat[self.chat_seen..].to_vec();
        self.chat_seen = self.chat.len();
        out
    }

    fn parse_rooms(&mut self, v: &Value) {
        let Some(arr) = v.get("rooms").and_then(|x| x.as_array()) else { return };
        self.rooms = arr
            .iter()
            .map(|r| RoomUi {
                code: r.get("code").and_then(|x| x.as_str()).unwrap_or("").to_string(),
                players: r.get("players").and_then(|x| x.as_u64()).unwrap_or(0) as usize,
                sides: array_bytes(r.get("sides")),
                started: r.get("started").and_then(|x| x.as_bool()).unwrap_or(false),
                paused: r.get("paused").and_then(|x| x.as_bool()).unwrap_or(false),
            })
            .collect();
    }

    fn parse_room(&mut self, v: &Value) {
        let mut room = self.room.take().unwrap_or_default();
        if let Some(code) = v.get("code").and_then(|x| x.as_str()) {
            room.code = code.to_string();
            self.code = Some(code.to_string());
        }
        let sides = array_bytes(v.get("sides"));
        if !sides.is_empty() {
            room.sides = sides;
        }
        let seats = seats_from(v.get("seats"));
        if !seats.is_empty() {
            room.seats = seats;
        }
        if let Some(x) = v.get("turn").and_then(|x| x.as_u64()) {
            room.turn = x as u32;
        }
        room.ai = array_bytes(v.get("ai"));
        if let Some(x) = v.get("started").and_then(|x| x.as_bool()) {
            room.started = x;
        }
        if let Some(x) = v.get("paused").and_then(|x| x.as_bool()) {
            room.paused = x;
        }
        if let Some(x) = v.get("missing").and_then(|x| x.as_bool()) {
            room.missing = x;
        }
        if let Some(why) = v.get("why").and_then(|x| x.as_str()) {
            self.status = Some(why.to_string());
        }
        self.local_side = room.seats.iter().find(|s| s.name == self.name && s.connected).map(|s| s.side);
        if !room.code.is_empty() || !room.seats.is_empty() {
            self.room = Some(room);
        } else {
            self.room = None;
        }
    }

    fn parse_start(&mut self, v: &Value) {
        let seed = v.get("seed").and_then(|x| x.as_u64()).unwrap_or(0) as u32;
        let map_w = v.get("map_w").and_then(|x| x.as_u64()).unwrap_or(96) as usize;
        let map_h = v.get("map_h").and_then(|x| x.as_u64()).unwrap_or(128) as usize;
        let difficulty = v.get("difficulty").and_then(|x| x.as_u64()).unwrap_or(1) as u8;
        let sides = array_bytes(v.get("sides"));
        let mission = v.get("mission").and_then(|x| x.as_u64()).map(|x| x as usize);
        let mut ai = array_bytes(v.get("ai"));
        if ai.is_empty() {
            if let Some(r) = self.room.as_ref() {
                ai = r.ai.clone();
            }
        }
        let local_side = self.room.as_ref().and_then(|r| r.seats.iter().find(|s| s.name == self.name && s.connected).map(|s| s.side));
        self.local_side = local_side;
        if let Some(r) = self.room.as_mut() {
            r.started = true;
            r.paused = false;
            r.missing = false;
            r.turn = 0;
            if !sides.is_empty() {
                r.sides = sides.clone();
            }
            r.ai = ai.clone();
        }
        self.start = Some(StartInfo { seed, map_w, map_h, difficulty, sides, local_side, mission, ai });
        self.error = None;
        self.status = None;
    }

    fn parse_turn(&mut self, v: &Value) {
        let turn = v.get("turn").and_then(|x| x.as_u64()).unwrap_or(0) as u32;
        if let Some(r) = self.room.as_mut() {
            r.turn = turn;
            r.ai = array_bytes(v.get("ai"));
        }
        let cmds = match v.get("cmds").cloned() {
            Some(v) => serde_json::from_value::<Vec<Command>>(v).unwrap_or_default(),
            None => Vec::new(),
        };
        let ai = array_bytes(v.get("ai"));
        self.turns.push((turn, cmds, ai));
    }

    fn parse_sum(&mut self, v: &Value) {
        let turn = v.get("turn").and_then(|x| x.as_u64()).unwrap_or(0) as u32;
        let sum = match v.get("sum").and_then(|x| x.as_u64()) {
            Some(s) => s,
            None => return,
        };
        let from = v.get("from").and_then(|x| x.as_u64()).map(|n| n as u8);
        self.checks.push((from, turn, sum));
    }

    pub fn ui(&self) -> MatchUi {
        let room = self.room.clone().unwrap_or_default();
        let local = self.local_side;
        let ready = room.seats.iter().find(|s| Some(s.side) == local).map(|s| s.ready).unwrap_or(false);
        let host = room.seats.iter().find(|s| s.side == 0);
        let is_host = local == Some(0) && host.map(|s| s.connected).unwrap_or(false);
        MatchUi {
            phase: self.phase(),
            connected: self.connected,
            name: self.name.clone(),
            code: room.code.is_empty().then(|| self.code.clone()).unwrap_or(Some(room.code.clone())).clone(),
            local_side: local,
            ready,
            is_host,
            sides: room.sides.clone(),
            ai: room.ai.clone(),
            seats: room.seats.iter().map(|s| SeatUi { side: s.side, name: s.name.clone(), ready: s.ready, connected: s.connected, ai: s.ai }).collect(),
            rooms: self.rooms.clone(),
            started: room.started,
            paused: room.paused,
            missing: room.missing,
            turn: room.turn,
            error: self.error.clone(),
            status: self.status.clone(),
            chat: self.chat.clone(),
        }
    }
}

fn array_bytes(v: Option<&Value>) -> Vec<u8> {
    v.and_then(|x| x.as_array())
        .map(|a| a.iter().filter_map(|x| x.as_u64().map(|n| n as u8)).collect())
        .unwrap_or_default()
}

fn seats_from(v: Option<&Value>) -> Vec<SeatInfo> {
    v.and_then(|x| x.as_array())
        .map(|arr| {
            arr.iter()
                .map(|s| SeatInfo {
                    side: s.get("side").and_then(|x| x.as_u64()).unwrap_or(0) as u8,
                    name: s.get("name").and_then(|x| x.as_str()).unwrap_or("").to_string(),
                    ready: s.get("ready").and_then(|x| x.as_bool()).unwrap_or(false),
                    connected: s.get("connected").and_then(|x| x.as_bool()).unwrap_or(false),
                    ai: s.get("ai").and_then(|x| x.as_bool()).unwrap_or(false),
                })
                .collect()
        })
        .unwrap_or_default()
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::commands::{Act, Rect};

    fn pop(client: &mut MatchClient) -> Value {
        let s = client.outbox.pop_front().expect("no request");
        serde_json::from_str(&s).expect("bad json")
    }

    #[test]
    fn the_bridge_turns_orders_into_json_and_turns_back_into_commands() {
        let mut client = MatchClient::new();
        client.on_connect("red");
        let req = pop(&mut client); // rooms
        assert_eq!(req["t"].as_str(), Some("rooms"));

        client.create(&[0, 2], 96, 128, 1);
        let req = pop(&mut client);
        assert_eq!(req["t"].as_str(), Some("create"));

        client.feed(r#"{"t":"room","code":"ABC123","sides":[0,2],"seats":[{"side":0,"name":"red","ready":false,"connected":true}],"turn":0,"started":false,"paused":false,"missing":false}"#);
        client.feed(r#"{"t":"start","seed":7,"map_w":96,"map_h":128,"difficulty":1,"sides":[0,2]}"#);
        let start = client.take_start().expect("start info");
        assert_eq!(start.seed, 7);
        assert_eq!(start.local_side, Some(0));
        assert_eq!(start.mission, None);

        client.create_coop(2, &[0, 2], 80, 72, 1);
        let coop = pop(&mut client);
        assert_eq!(coop["t"].as_str(), Some("create"));
        assert_eq!(coop["mission"].as_u64(), Some(2));
        client.feed(r#"{"t":"start","seed":8,"map_w":80,"map_h":72,"difficulty":1,"sides":[0,2],"mission":2}"#);
        let coop_start = client.take_start().expect("co-op start info");
        assert_eq!(coop_start.mission, Some(2));

        client.send_commands(&[Command { side: 0, seq: 0, act: Act::Dig(Rect::new(1, 2, 3, 4)) }]);
        let req = pop(&mut client);
        assert_eq!(req["t"].as_str(), Some("cmds"));
        assert_eq!(req["cmds"][0]["side"].as_u64(), Some(0));

        client.feed(r#"{"t":"turn","turn":1,"cmds":[{"side":0,"seq":0,"act":{"Dig":{"x0":1,"y0":2,"x1":3,"y1":4}}}]}"#);
        let turns = client.take_turns();
        assert_eq!(turns.len(), 1);
        assert_eq!(turns[0].1[0].side, 0);
        assert!(matches!(turns[0].1[0].act, Act::Dig(_)));

        client.feed(r#"{"t":"sum","from":2,"turn":1,"sum":42}"#);
        let checks = client.take_checks();
        assert_eq!(checks[0], (Some(2), 1, 42));

        client.chat("hello", true);
        let req = pop(&mut client);
        assert_eq!(req["t"].as_str(), Some("chat"));
        assert_eq!(req["channel"].as_str(), Some("team"));
        client.feed(r#"{"t":"chat","name":"red","text":"hello","side":0,"channel":"team"}"#);
        let chat = client.take_new_chat();
        assert_eq!(chat[0], (Some(0), "red".to_string(), "hello".to_string()));
    }

    #[test]
    fn the_bridge_times_the_server_ping() {
        let mut client = MatchClient::new();
        client.on_connect("red");
        pop(&mut client); // rooms

        client.tick_ping(10.0);
        let req = pop(&mut client);
        assert_eq!(req["t"].as_str(), Some("ping"));
        assert_eq!(req["c"].as_u64(), Some(1));

        client.feed_at(r#"{"t":"pong","c":1}"#, 10.25);
        assert!(client.ping_ms > 200.0 && client.ping_ms < 300.0, "the pong came 250 ms after the ping");

        client.tick_ping(11.0);
        assert!(client.outbox.is_empty(), "the next ping waits for its two-second interval");

        client.tick_ping(12.0);
        let next = pop(&mut client);
        assert_eq!(next["c"].as_u64(), Some(2));
    }

    #[test]
    fn the_bridge_holds_ai_seats_through_the_lobby() {
        let mut client = MatchClient::new();
        client.on_connect("red");
        pop(&mut client); // rooms

        client.create(&[0, 2, 3, 4], 96, 128, 1);
        pop(&mut client); // create

        client.set_ai(3, true);
        let req = pop(&mut client);
        assert_eq!(req["t"].as_str(), Some("set_ai"));
        assert_eq!(req["side"].as_u64(), Some(3));
        assert_eq!(req["ai"].as_bool(), Some(true));

        client.feed(r#"{"t":"room","code":"ABC123","sides":[0,2,3,4],"seats":[{"side":0,"name":"red","ready":false,"connected":true,"ai":false},{"side":2,"name":"","ready":false,"connected":false,"ai":false},{"side":3,"name":"","ready":false,"connected":false,"ai":true},{"side":4,"name":"","ready":false,"connected":false,"ai":false}],"ai":[3],"turn":0,"started":false,"paused":false,"missing":false}"#);
        let ui = client.ui();
        assert_eq!(ui.ai, vec![3u8]);
        assert!(ui.seats.iter().any(|s| s.side == 3 && s.ai));
        assert!(ui.seats.iter().any(|s| s.side == 2 && !s.connected && !s.ai));

        client.feed(r#"{"t":"start","seed":7,"map_w":96,"map_h":128,"difficulty":1,"sides":[0,3],"ai":[3]}"#);
        let start = client.take_start().expect("start info with ai seats");
        assert_eq!(start.sides, vec![0u8, 3u8]);
        assert_eq!(start.ai, vec![3u8]);
    }
}