use super::traits::{Game, GameState};
use crate::roulette::{is_even, is_odd, BetTarget, Bets, Outside};

pub const ROULETTE_BOARD_LINES: usize = 12;

/// Width of one number cell on the felt.
const CELL: usize = 5;
const NUM_COLUMNS: usize = 12;
const NUM_WIDTH: usize = CELL * NUM_COLUMNS;
const THIRD_WIDTH: usize = NUM_WIDTH / 3;
const OUTSIDE_WIDTH: usize = NUM_WIDTH / 6;
const OUTSIDE_ORDER: [Outside; 6] = [
    Outside::Low,
    Outside::Even,
    Outside::Red,
    Outside::Black,
    Outside::Odd,
    Outside::High,
];

pub struct RouletteGame;

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Direction {
    Up,
    Down,
    Left,
    Right,
}

/// Where the betting cursor is.
///
/// Over the numbers the cursor sits on a *lattice point*, the way a chip sits
/// between numbers on a real felt: an inner point covers four numbers (corner),
/// an edge point covers two (split), and an outer corner is a straight number.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Cursor {
    Zero,
    Lattice { x: usize, y: usize },
    Dozen(usize),
    Column(usize),
    Outside(usize),
}

impl Default for Cursor {
    fn default() -> Self {
        // Bottom-left number (1).
        Cursor::Lattice { x: 0, y: 3 }
    }
}

impl Cursor {
    pub fn parse(raw: &str) -> Self {
        let parts: Vec<&str> = raw.split(':').collect();
        match parts.as_slice() {
            ["zero"] => Cursor::Zero,
            ["lattice", x, y] => match (x.parse::<usize>(), y.parse::<usize>()) {
                (Ok(x), Ok(y)) if x <= NUM_COLUMNS && y <= 3 => Cursor::Lattice { x, y },
                _ => Cursor::default(),
            },
            ["dozen", index] => parse_index(index).map(Cursor::Dozen).unwrap_or_default(),
            ["column", index] => parse_index(index).map(Cursor::Column).unwrap_or_default(),
            ["outside", index] => match index.parse::<usize>() {
                Ok(index) if index < OUTSIDE_ORDER.len() => Cursor::Outside(index),
                _ => Cursor::default(),
            },
            _ => Cursor::default(),
        }
    }

    pub fn encoded(&self) -> String {
        match self {
            Cursor::Zero => "zero".to_string(),
            Cursor::Lattice { x, y } => format!("lattice:{x}:{y}"),
            Cursor::Dozen(index) => format!("dozen:{index}"),
            Cursor::Column(index) => format!("column:{index}"),
            Cursor::Outside(index) => format!("outside:{index}"),
        }
    }

    pub fn target(&self) -> Option<BetTarget> {
        match self {
            Cursor::Zero => Some(BetTarget::Straight { number: 0 }),
            Cursor::Lattice { x, y } => lattice_target(*x, *y),
            Cursor::Dozen(index) => Some(BetTarget::Dozen {
                index: *index as u8,
            }),
            Cursor::Column(index) => Some(BetTarget::Column {
                index: *index as u8,
            }),
            Cursor::Outside(index) => Some(BetTarget::Outside {
                kind: OUTSIDE_ORDER[*index],
            }),
        }
    }

    /// Numbers the cursor would cover, for highlighting the felt.
    pub fn numbers(&self) -> Vec<u8> {
        self.target().map(|target| target.numbers()).unwrap_or_default()
    }

    pub fn moved(&self, direction: Direction) -> Cursor {
        match (*self, direction) {
            (Cursor::Zero, Direction::Down) => Cursor::Lattice { x: 0, y: 0 },
            (Cursor::Zero, _) => Cursor::Zero,

            (Cursor::Lattice { x, y }, Direction::Left) => Cursor::Lattice {
                x: x.saturating_sub(1),
                y,
            },
            (Cursor::Lattice { x, y }, Direction::Right) => Cursor::Lattice {
                x: (x + 1).min(NUM_COLUMNS),
                y,
            },
            (Cursor::Lattice { x: _, y: 0 }, Direction::Up) => Cursor::Zero,
            (Cursor::Lattice { x, y }, Direction::Up) => Cursor::Lattice { x, y: y - 1 },
            (Cursor::Lattice { x, y: 3 }, Direction::Down) => Cursor::Dozen((x / 4).min(2)),
            (Cursor::Lattice { x, y }, Direction::Down) => Cursor::Lattice { x, y: y + 1 },

            (Cursor::Dozen(index), Direction::Left) => Cursor::Dozen(index.saturating_sub(1)),
            (Cursor::Dozen(index), Direction::Right) => Cursor::Dozen((index + 1).min(2)),
            (Cursor::Dozen(index), Direction::Up) => Cursor::Lattice {
                x: 4 * index + 1,
                y: 3,
            },
            (Cursor::Dozen(index), Direction::Down) => Cursor::Column(index),

            (Cursor::Column(index), Direction::Left) => Cursor::Column(index.saturating_sub(1)),
            (Cursor::Column(index), Direction::Right) => Cursor::Column((index + 1).min(2)),
            (Cursor::Column(index), Direction::Up) => Cursor::Dozen(index),
            (Cursor::Column(index), Direction::Down) => Cursor::Outside(index * 2),

            (Cursor::Outside(index), Direction::Left) => {
                Cursor::Outside(index.saturating_sub(1))
            }
            (Cursor::Outside(index), Direction::Right) => {
                Cursor::Outside((index + 1).min(OUTSIDE_ORDER.len() - 1))
            }
            (Cursor::Outside(index), Direction::Up) => Cursor::Column(index / 2),
            (Cursor::Outside(index), Direction::Down) => Cursor::Outside(index),
        }
    }
}

fn parse_index(raw: &str) -> Option<usize> {
    raw.parse::<usize>().ok().filter(|index| *index < 3)
}

/// Numbers under a lattice point: 1 (outer corner), 2 (edge) or 4 (inner).
fn lattice_target(x: usize, y: usize) -> Option<BetTarget> {
    let cell = |column: isize, row: isize| -> Option<u8> {
        if !(0..NUM_COLUMNS as isize).contains(&column) || !(0..3isize).contains(&row) {
            return None;
        }
        Some((3 * column + (3 - row)) as u8)
    };

    let x = x as isize;
    let y = y as isize;
    let mut numbers: Vec<u8> = [(x - 1, y - 1), (x, y - 1), (x - 1, y), (x, y)]
        .into_iter()
        .filter_map(|(column, row)| cell(column, row))
        .collect();
    numbers.sort_unstable();

    match numbers.as_slice() {
        [number] => Some(BetTarget::Straight { number: *number }),
        [a, b] => Some(BetTarget::Split { a: *a, b: *b }),
        [a, b, c, d] => Some(BetTarget::Corner {
            numbers: [*a, *b, *c, *d],
        }),
        _ => None,
    }
}

impl RouletteGame {
    pub fn new() -> Self {
        Self
    }

    fn bets(state: &GameState) -> Bets {
        state
            .data
            .get("bets")
            .and_then(|raw| Bets::from_json(raw).ok())
            .unwrap_or_default()
    }

    fn cursor(state: &GameState) -> Cursor {
        state
            .data
            .get("cursor")
            .map(|raw| Cursor::parse(raw))
            .unwrap_or_default()
    }

    fn zero_cell(cursor: Cursor) -> String {
        let cell = if cursor == Cursor::Zero {
            "[ 0 ]".to_string()
        } else {
            format!("{:^CELL$}", 0)
        };
        format!("{cell:<NUM_WIDTH$}")
    }

    fn number_row(row: usize, covered: &[u8]) -> String {
        (0..NUM_COLUMNS)
            .map(|column| {
                let number = (3 * column + (3 - row)) as u8;
                if covered.contains(&number) {
                    format!("[{number:^3}]")
                } else {
                    format!("{number:^CELL$}")
                }
            })
            .collect()
    }

    fn wide_cell(label: &str, width: usize, active: bool) -> String {
        if active {
            format!("[{:^inner$}]", label, inner = width - 2)
        } else {
            format!("{label:^width$}")
        }
    }

    fn dozens_row(cursor: Cursor) -> String {
        ["1st 12", "2nd 12", "3rd 12"]
            .iter()
            .enumerate()
            .map(|(index, label)| {
                Self::wide_cell(label, THIRD_WIDTH, cursor == Cursor::Dozen(index))
            })
            .collect()
    }

    fn columns_row(cursor: Cursor) -> String {
        ["col 1 2:1", "col 2 2:1", "col 3 2:1"]
            .iter()
            .enumerate()
            .map(|(index, label)| {
                Self::wide_cell(label, THIRD_WIDTH, cursor == Cursor::Column(index))
            })
            .collect()
    }

    fn outside_row(cursor: Cursor) -> String {
        OUTSIDE_ORDER
            .iter()
            .enumerate()
            .map(|(index, kind)| {
                Self::wide_cell(kind.label(), OUTSIDE_WIDTH, cursor == Cursor::Outside(index))
            })
            .collect()
    }

    fn bets_line(bets: &Bets) -> String {
        let mut parts: Vec<String> = bets
            .chips
            .iter()
            .filter(|chip| chip.amount > 0)
            .map(|chip| format!("{} {}", chip.target.label(), chip.amount))
            .collect();
        if parts.is_empty() {
            parts.push("(none)".to_string());
        }
        let mut list = parts.join("  ");
        if list.chars().count() > 40 {
            list = list.chars().take(39).collect::<String>() + "…";
        }
        format!("Bets: {list}   Total: {} PLN", bets.total())
    }

    fn status_line(state: &GameState) -> String {
        if let Some(error) = state.data.get("error") {
            if !error.is_empty() {
                return format!("ERROR: {error}");
            }
        }

        match state.data.get("status").map(String::as_str) {
            Some("result") => {
                let number = state.data.get("number").map(String::as_str).unwrap_or("?");
                let color = state
                    .data
                    .get("color")
                    .map(|value| value.to_uppercase())
                    .unwrap_or_default();
                let parity = number
                    .parse::<u8>()
                    .ok()
                    .map(|number| {
                        if is_even(number) {
                            " EVEN"
                        } else if is_odd(number) {
                            " ODD"
                        } else {
                            ""
                        }
                    })
                    .unwrap_or("");
                let winnings = state
                    .data
                    .get("winnings")
                    .map(String::as_str)
                    .unwrap_or("0");
                let stake = state.bet_amount;
                if winnings == "0" {
                    format!("No win at {number} {color}{parity}")
                } else {
                    let profit = winnings.parse::<u64>().unwrap_or(0).saturating_sub(stake);
                    format!("Won {winnings} PLN at {number} {color}{parity}   (+{profit})")
                }
            }
            Some("spinning") => "Spinning...".to_string(),
            _ => "Arrows move, ENTER places the chip, SPACE spins.".to_string(),
        }
    }
}

impl Game for RouletteGame {
    fn get_name(&self) -> &'static str {
        "Roulette"
    }

    fn render(&self, state: &GameState) -> String {
        let bets = Self::bets(state);
        let chip = state.data.get("chip").map(String::as_str).unwrap_or("10");
        let balance = state.data.get("balance").map(String::as_str).unwrap_or("?");
        let cursor = Self::cursor(state);
        let covered = cursor.numbers();

        let lines = [
            "=== ROULETTE ===".to_string(),
            format!("Balance: {balance} PLN   Chip: {chip} PLN"),
            Self::zero_cell(cursor),
            Self::number_row(0, &covered),
            Self::number_row(1, &covered),
            Self::number_row(2, &covered),
            Self::dozens_row(cursor),
            Self::columns_row(cursor),
            Self::outside_row(cursor),
            Self::bets_line(&bets),
            Self::status_line(state),
            "[ARROWS] Move  [ENTER] Bet  [C]lear  [+/-] Chip  [SPACE] Spin  [Q] Quit"
                .to_string(),
        ];
        lines.join("\r\n")
    }

    fn render_lines(&self, _state: &GameState) -> usize {
        ROULETTE_BOARD_LINES
    }

    fn get_help(&self) -> String {
        "ROULETTE (European)\n\
        ==================\n\
        37 pockets: 0 plus 1-36. 0 is green and loses every outside bet.\n\
        \n\
        Betting with the cursor:\n\
        arrows - move over the felt; between numbers picks a split or corner\n\
        ENTER - place the current chip where the cursor is\n\
        C - clear all bets\n\
        + or = / - - change the chip size\n\
        SPACE - spin when at least one bet is placed\n\
        Q - exit\n\
        \n\
        Payouts (returned per unit staked):\n\
        straight 36x, split 18x, corner 9x\n\
        dozen 3x, column 3x\n\
        red/black, even/odd, 1-18/19-36: 2x\n\
        Multiple bets are settled independently and added together."
            .to_string()
    }
}