use super::traits::{Game, GamePhase, GameState};
use crate::slots::{paytable_lines, LINE_NAMES, REELS, ROWS};

/// Height of the game board. It must never depend on the spin result.
pub const SLOT_BOARD_LINES: usize = 10;

pub struct SlotsGame;

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

    fn cell(chars: &[char], row: usize, col: usize, winning: &[usize]) -> String {
        let symbol = if chars.len() == REELS * ROWS {
            chars.get(col * ROWS + row).copied().unwrap_or('?')
        } else if chars.len() == 3 && row == 0 {
            // Legacy 3-symbol server: degrade to the first row.
            chars.get(col).copied().unwrap_or('?')
        } else {
            '?'
        };

        if winning.contains(&(col * ROWS + row)) {
            format!("{{ {} }}", symbol)
        } else {
            format!("[ {} ]", symbol)
        }
    }

    fn highlighted_cells(state: &GameState) -> Vec<usize> {
        state
            .data
            .get("win_cells")
            .map(|raw| {
                raw.split(',')
                    .filter_map(|value| value.trim().parse::<usize>().ok())
                    .collect()
            })
            .unwrap_or_default()
    }

    fn render_grid(&self, reels: &str, winning: &[usize]) -> [String; ROWS] {
        let chars: Vec<char> = reels.chars().collect();
        std::array::from_fn(|row| {
            (0..REELS)
                .map(|col| Self::cell(&chars, row, col, winning))
                .collect::<Vec<_>>()
                .join(" ")
        })
    }

    fn render_status(&self, state: &GameState) -> String {
        if let Some(error) = state.data.get("error") {
            return format!("ERROR: {error}");
        }
        if state.phase == GamePhase::Playing {
            return "Spinning...".to_string();
        }
        if state.phase == GamePhase::Finished {
            let winnings = state
                .data
                .get("winnings")
                .map(String::as_str)
                .unwrap_or("0");
            if winnings != "0" {
                return match state.data.get("win_type").map(String::as_str) {
                    Some("mega") => format!("MEGA WIN! {winnings} PLN"),
                    Some("big") => format!("BIG WIN! {winnings} PLN"),
                    _ => format!("Won {winnings} PLN"),
                };
            }
            return "No win.".to_string();
        }
        "Press [SPACE] to spin!".to_string()
    }

    fn render_win_lines(&self, state: &GameState) -> String {
        if state.phase != GamePhase::Finished {
            return String::new();
        }
        match state.data.get("win_lines").map(String::as_str) {
            Some(lines) if !lines.is_empty() && lines != "-" => {
                let named: Vec<String> = lines
                    .split(',')
                    .filter_map(|raw| raw.trim().parse::<usize>().ok())
                    .map(|line| {
                        let name = line
                            .checked_sub(1)
                            .and_then(|index| LINE_NAMES.get(index))
                            .copied();
                        match name {
                            Some(name) => format!("{line} ({name})"),
                            None => line.to_string(),
                        }
                    })
                    .collect();
                format!("Winning lines: {}", named.join(", "))
            }
            _ => String::new(),
        }
    }
}

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

    fn render(&self, state: &GameState) -> String {
        let reels = state.data.get("reels").cloned().unwrap_or_default();
        let balance = state.data.get("balance").map(String::as_str).unwrap_or("?");
        let winning = Self::highlighted_cells(state);
        let grid = self.render_grid(&reels, &winning);
        let paytable = paytable_lines();

        format!(
            "=== SLOTS ===\r\nBet: {} PLN   Balance: {} PLN\r\n{}\r\n{}\r\n{}\r\n{}\r\n{}\r\n{}\r\n{}\r\n[+/-] Bet   [SPACE] Spin   [Q] Quit",
            state.bet_amount,
            balance,
            grid[0],
            grid[1],
            grid[2],
            paytable[0],
            paytable[1],
            self.render_status(state),
            self.render_win_lines(state)
        )
    }

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

    fn get_help(&self) -> String {
        "SLOTS GAME\n\
        =========\n\
        5 reels x 3 rows, 5 paylines.\n\
        A win needs 3, 4 or 5 matching symbols from reel 1 on a payline.\n\
        \n\
        Payout = total bet x symbol x shape\n\
        Symbols: C=1 L=2 O=3 G=4 D=6 S=10\n\
        Shapes: 3 of a kind=1, 4 of a kind=3, 5 of a kind=14\n\
        \n\
        Lines: 1 top, 2 middle, 3 bottom, 4 V, 5 inverted V\n\
        Multiple winning lines are added together.\n\
        \n\
        Symbols: C=Cherry, L=Lemon, O=Orange, G=Grapes, D=Diamond, S=Seven\n\
        \n\
        Controls:\n\
        SPACE - Spin the reels\n\
        + or = - Increase total bet\n\
        - - Decrease total bet\n\
        Q - Exit the game"
            .to_string()
    }
}