//! Game board.

use std::collections::HashMap;
use std::rc::Rc;

use termion::cursor;
use termion::event::Key;

use crate::game::Position;
use crate::chars;
use crate::cell::Cell;
use crate::cell_grid::CellGrid;
use crate::cursor::{Cursor, KeyHandleResult};
use crate::str_utils;

const TEXT_ALIGN_CENTER: &'static str = "|^|";
const TEXT_ALIGN_RIGHT: &'static str = "|>|";

/// Resources for cell content.
///
/// This can be useful when board has a lot of cells with the same content.
pub type ResourceTable = HashMap<u16, String>;

/// Cell updates array.
///
/// Each array element is a tuple of cell content and cell position.
pub type CellUpdates = Vec<(Cell, Position)>;

/// Board structure.
pub struct Board {
    /// Board top left position.
    position: Position,
    /// Total board width in characters (with borders).
    width: usize,
    /// Total board height in characters (with borders).
    height: usize,
    rows: usize,
    columns: usize,
    cell_width: usize,
    cell_height: usize,
    cell_borders: bool,
    grid: CellGrid,
    resources: Rc<Option<ResourceTable>>,
    cursor: Option<Cursor>,
    message_lines: Option<Vec<String>>,
    /// Need to redraw all cells and borders (for example, after message dialog was closed).
    update_all: bool,
}

impl Board {
    /// Creates new board.
    ///
    /// # Arguments
    ///
    /// `width` - horizontal number of cells (number of columns)
    ///
    /// `height` - vertical number of cells (number of rows)
    ///
    /// `cell_width` - cell width in characters
    ///
    /// `cell_height` - cell height in characters
    ///
    /// `cell_borders` - if `true` show cell borders
    ///
    /// `resources` - resource table (optional)
    ///
    /// # Examples
    ///
    /// A board for 3x3 tic-tac-toe game. Cell has 10x5 size to look square in terminal.
    /// ```no_run
    /// fn create_resources() -> ResourceTable {
    ///     let mut res = ResourceTable::new();
    ///     res.insert(0, String::from("    OOO      O   O    O     O    O   O      OOO   "));
    ///     res.insert(1, String::from("   X   X      X X        X        X X      X   X  "));
    ///     res
    /// }
    /// let mut board = Board::new(3, 3, 10, 5, true, Some(create_resources()));
    /// ```
    pub fn new(width: usize, height: usize, cell_width: usize, cell_height: usize,
               cell_borders: bool, resources: Option<ResourceTable>) -> Self {
        let mut w_borders = 2;
        let mut h_borders = 2;
        if cell_borders {
            w_borders += width - 1;
            h_borders += height - 1;
        }
        let w = width * cell_width + w_borders;
        let h = height * cell_height + h_borders;

        let res_table = Rc::new(resources);
        let grid = CellGrid::new(width, height, cell_width, cell_height, Rc::clone(&res_table));

        Board {
            position: Position(1, 1),
            width: w,
            height: h,
            rows: height,
            columns: width,
            cell_width,
            cell_height,
            cell_borders,
            grid,
            resources: Rc::clone(&res_table),
            cursor: None,
            message_lines: None,
            update_all: false,
        }
    }

    /// Initializes board with cells and cursor (optional).
    ///
    /// The cells will be filled from vector by rows.
    ///
    /// # Panics
    ///
    /// Panics `cells` contain wrong number of elements.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// let mut board = Board::new(2, 2, 1, 1, false, None));
    /// board.init_from_vec(&vec![Cell::Empty, Cell::Char('x'), Cell::Empty, Cell::Char('o')],
    ///                     None);
    /// ```
    pub fn init_from_vec(&mut self, cells: &Vec<Cell>, cursor: Option<Cursor>) {
        if cells.len() != self.rows * self.columns {
            panic!("Invalid number of cells.");
        }
        self.grid.init_from_vec(cells);
        self.add_cursor(cursor);
    }

    /// Initializes board with cells and cursor (optional).
    ///
    /// The cells will be filled from string by rows.
    ///
    /// This is an additional initialization method. It might be useful if board has 1x1 cells and
    /// all cells contain 1 character without styling.
    ///
    /// # Implementation note
    ///
    /// We iterate string using `chars()` method, it iterates through Unicode code points. Do not
    /// use Unicode symbols which consist of more than 1 code points.
    ///
    /// # Panics
    ///
    /// Panics `cells` contain wrong number of elements.
    ///
    /// Panics if cell size is not 1x1.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// let mut board = Board::new(4, 4, 1, 1, false, None));
    /// board.init_from_str(&"x    o    x    o", None);
    /// ```
    /// The following code does the same.
    /// ```no_run
    /// let mut board = Board::new(4, 4, 1, 1, false, None));
    /// board.init_from_vec(&vec![Cell::Char('x'), Cell::Empty, Cell::Empty, Cell::Empty,
    ///                           Cell::Empty, Cell::Char('o'), Cell::Empty, Cell::Empty,
    ///                           Cell::Empty, Cell::Empty, Cell::Char('x'), Cell::Empty,
    ///                           Cell::Empty, Cell::Empty, Cell::Empty, Cell::Char('o')],
    ///                     None);
    /// ```
    pub fn init_from_str(&mut self, cells: &str, cursor: Option<Cursor>) {
        if cells.chars().count() != self.rows * self.columns {
            panic!("Invalid number of cells.");
        }
        if self.cell_width != 1 && self.cell_height != 1 {
            panic!("You can initialize cells from string for board with 1x1 cells only.");
        }
        self.grid.init_from_str(cells);
        self.add_cursor(cursor);
    }

    fn add_cursor(&mut self, cursor: Option<Cursor>) {
        if let Some(mut cur) = cursor {
            cur.init(self.rows, self.columns, &mut self.grid);
            self.cursor = Some(cur);
        }
    }

    pub(crate) fn get_width(&self) -> usize {
        self.width
    }

    pub(crate) fn get_height(&self) -> usize {
        self.height
    }

    pub(crate) fn set_position(&mut self, pos: Position) {
        self.position = pos;
    }

    pub(crate) fn get_border(&self) -> String {
        let mut y = self.position.1 as u16;
        // Add chars to row width for Goto sequences
        let mut res =
            String::with_capacity((self.width + str_utils::GOTO_SEQUENCE_WIDTH) * self.height);

        for h in 0..self.height {
            res.push_str(&format!("{}", cursor::Goto(self.position.0 as u16, y)));
            for w in 0..self.width {
                match self.get_border_char(w, h) {
                    Some(border_ch) => {
                        res.push(border_ch);
                    },
                    None => {
                        res.push(' ');
                    }
                };
            }
            y += 1;
        }
        res
    }

    pub(crate) fn get_updates(&mut self) -> Option<String> {
        let msg_dlg = self.get_message_dialog();
        if msg_dlg.is_some() {
            return msg_dlg
        }

        if !self.update_all && !self.grid.has_updates() {
            return None
        }

        let mut res = String::with_capacity(self.width * self.height);
        let update_all = self.update_all || self.grid.need_update_all();
        if self.update_all {
            // We need to redraw the whole board with borders to wipe out message dialog.
            res.push_str(&self.get_border());
        }

        if update_all && self.cell_width == 1 && self.cell_height == 1 && !self.cell_borders {
            // If we need to update all cells and board has 1x1 cells and no borders,
            // we can simplify the process.
            for (i, cell) in self.grid.iter().enumerate() {
                if i % self.columns == 0 {
                    let (x, y) = self.get_cell_top_left(i);
                    res.push_str(&format!("{}", cursor::Goto(x, y)));
                }
                cell.add_value_to_str(&mut res, Rc::clone(&self.resources));
            }
        } else if update_all {
            for (i, cell) in self.grid.iter().enumerate() {
                let (x, y) = self.get_cell_top_left(i);
                res.push_str(
                    &cell.get_content(self.cell_width, self.cell_height, x, y,
                                      Rc::clone(&self.resources))
                );
            }
        } else {
            for (cell, pos) in self.grid.updated_iter() {
                let (x, y) = self.get_cell_top_left(pos);
                res.push_str(
                    &cell.get_content(self.cell_width, self.cell_height, x, y,
                                      Rc::clone(&self.resources))
                );
            }
        }
        self.grid.update_complete();
        self.update_all = false;
        Some(res)
    }

    pub(crate) fn update_cells(&mut self, updates: CellUpdates) {
        if self.message_lines.is_some() {
            panic!("You can't update cells while message is open. Use hide_message() to close it.");
        }
        self.grid.update_cells(&updates);
        if let Some(ref mut cursor) = self.cursor {
            cursor.check_updates(&updates, &mut self.grid)
        }
    }

    pub(crate) fn handle_key(&mut self, key: Key) -> KeyHandleResult {
        match self.cursor {
            Some(ref mut cursor) => cursor.handle_key(key, &mut self.grid),
            None => KeyHandleResult::NotHandled
        }
    }

    pub(crate) fn show_message(&mut self, lines: &[&str]) {
        let mut v = Vec::with_capacity(lines.len());
        for &l in lines {
            v.push(String::from(l));
        }
        self.message_lines = Some(v);
    }

    pub(crate) fn hide_message(&mut self) {
        self.message_lines = None;
        self.update_all = true;
    }

    fn get_message_dialog(&self) -> Option<String> {
        if let Some(ref msg_lines) = self.message_lines {
            let line_max_len = msg_lines.iter().map(|x| str_utils::get_str_len(x)).max()
                    .expect("Message lines slice must not be empty.");
            // We want to have at least 1 character margin between border and text.
            // So 8 means: board border + margin + dialog border + margin, from both sides.
            let dlg_w = line_max_len.min(self.width - 8) + 4;
            let dlg_h = msg_lines.len().min(self.height - 8) + 4;
            // Center dialog on the board.
            let x = (self.position.0 + (self.width - dlg_w) / 2) as u16;
            let mut y = (self.position.1 + (self.height - dlg_h) / 2) as u16;

            let mut res = String::with_capacity((dlg_w + str_utils::GOTO_SEQUENCE_WIDTH) * dlg_h);
            res.push_str(&format!(
                "{}{}{}{}{}{}{}{}{}",
                cursor::Goto(x, y),
                chars::DOUBLE_BORDER_TOP_LEFT,
                chars::DOUBLE_BORDER_HOR_LINE.to_string().repeat(dlg_w - 2),
                chars::DOUBLE_BORDER_TOP_RIGHT,
                cursor::Goto(x, y + 1),
                chars::DOUBLE_BORDER_VERT_LINE,
                " ".repeat(dlg_w - 2),
                chars::DOUBLE_BORDER_VERT_LINE,
                cursor::Goto(x, y + 2),
            ));
            y += 2;

            for i in 2..dlg_h - 2 {
                y += 1;
                let line = &msg_lines[i - 2];
                let s = if line.starts_with(TEXT_ALIGN_CENTER) {
                    let ll = &line[TEXT_ALIGN_CENTER.len()..];
                    if str_utils::get_str_len(ll) < dlg_w - 4 {
                        format!("{:^width$}", ll, width = dlg_w - 4)
                    } else {
                        str_utils::get_str_range(ll, 0, dlg_w - 4).to_string()
                    }
                } else if line.starts_with(TEXT_ALIGN_RIGHT) {
                    let ll = &line[TEXT_ALIGN_CENTER.len()..];
                    if str_utils::get_str_len(ll) < dlg_w - 4 {
                        format!("{:>width$}", ll, width = dlg_w - 4)
                    } else {
                        str_utils::get_str_range(ll, 0, dlg_w - 4).to_string()
                    }
                } else {
                    if str_utils::get_str_len(line) < dlg_w - 4 {
                        format!("{:width$}", &line, width = dlg_w - 4)
                    } else {
                        str_utils::get_str_range(line, 0, dlg_w - 4).to_string()
                    }
                };
                res.push_str(&format!(
                    "{} {} {}{}",
                    chars::DOUBLE_BORDER_VERT_LINE,
                    s,
                    chars::DOUBLE_BORDER_VERT_LINE,
                    cursor::Goto(x, y),
                ));
            }

            res.push_str(&format!(
                "{}{}{}{}{}{}{}",
                chars::DOUBLE_BORDER_VERT_LINE,
                " ".repeat(dlg_w - 2),
                chars::DOUBLE_BORDER_VERT_LINE,
                cursor::Goto(x, y + 1),
                chars::DOUBLE_BORDER_BOTTOM_LEFT,
                chars::DOUBLE_BORDER_HOR_LINE.to_string().repeat(dlg_w - 2),
                chars::DOUBLE_BORDER_BOTTOM_RIGHT
            ));
            Some(res)
        } else {
            None
        }
    }

    fn get_border_char(&self, w: usize, h: usize) -> Option<char> {
        let h_cell_border = h % (self.cell_height + 1) == 0;
        let v_cell_border = w % (self.cell_width + 1) == 0;

        if w == 0 && h == 0 {
            Some(chars::DOUBLE_BORDER_TOP_LEFT)
        } else if w == self.width - 1 && h == 0 {
            Some(chars::DOUBLE_BORDER_TOP_RIGHT)
        } else if w == 0 && h == self.height -1  {
            Some(chars::DOUBLE_BORDER_BOTTOM_LEFT)
        } else if w == self.width - 1 && h == self.height -1 {
            Some(chars::DOUBLE_BORDER_BOTTOM_RIGHT)
        } else if h == 0  {
            if self.cell_borders && v_cell_border {
                Some(chars::DOUBLE_BORDER_JOIN_UP)
            } else {
                Some(chars::DOUBLE_BORDER_HOR_LINE)
            }
        } else if h == self.height -1  {
            if self.cell_borders && v_cell_border {
                Some(chars::DOUBLE_BORDER_JOIN_DOWN)
            } else {
                Some(chars::DOUBLE_BORDER_HOR_LINE)
            }
        } else if w == 0 {
            if self.cell_borders && h_cell_border {
                Some(chars::DOUBLE_BORDER_JOIN_LEFT)
            } else {
                Some(chars::DOUBLE_BORDER_VERT_LINE)
            }
        } else if w == self.width - 1 {
            if self.cell_borders && h_cell_border {
                Some(chars::DOUBLE_BORDER_JOIN_RIGHT)
            } else {
                Some(chars::DOUBLE_BORDER_VERT_LINE)
            }
        } else if self.cell_borders {
            if h_cell_border && v_cell_border {
                Some(chars::SINGLE_BORDER_CROSS)
            } else if h_cell_border {
                Some(chars::SINGLE_BORDER_HOR_LINE)
            } else if v_cell_border {
                Some(chars::SINGLE_BORDER_VERT_LINE)
            } else {
                None
            }
        } else {
            None
        }
    }

    fn get_cell_top_left(&self, pos: usize) -> (u16, u16) {
        let start_x = self.position.0 + 1;
        let start_y = self.position.1 + 1;
        let step_x = if self.cell_borders {
            self.cell_width + 1
        } else {
            self.cell_width
        };
        let step_y = if self.cell_borders {
            self.cell_height + 1
        } else {
            self.cell_height
        };
        let x = start_x + (pos % self.columns) * step_x;
        let y = start_y + (pos / self.columns) * step_y;
        (x as u16, y as u16)
    }
}