import { Player, GridCellState, GameState, clone, ShipType, isShipType, isShipCell, isValidTargetCell } from '../module/util.js'
import { InvalidShipPlacementError, InvalidAdvanceStateError, InvalidMissileFireAttemptError } from '../module/errors.js'
/**
* Singleton service for managing the state of the game.
*/
export class GameStateService {
/**
* A mapping of player => game board state.
* @private
* @type {object}
*/
player_x_game_board = {}
/**
* A mapping of player => ship definitions.
* @private
* @type {object}
*/
player_x_ships = {}
/**
* An array of all players. This is mostly for internal purposes.
* @private
* @type {string[]}
*/
players = [Player.One, Player.Two]
/**
* Number of rows in the grid.
* @private
* @type {number}
*/
n_rows = 9
/**
* Number of cols in the grid.
* @private
* @type {number}
*/
n_cols = 9
/**
* Number boats placed on the board.
* @private
* @type {number}
*/
n_boats = 1
/**
* gets the number of boats placed on the board
* @private
* @return {number}
*/
get_n_boats(){
return (this.n_boats);
}
/**
* sets the number of boats to a valid number
* @private
* @return none
*/
set_n_boats(number){
if(number >= 1 && number <= 5 )
{
this.n_boats = number;
}
}
/**
* Given the number of boats set by the player (n_boats), return an array
* of possible ShipTypes.
* @return {string[]}
*/
get_possible_boats(){
if (this.get_n_boats() === 1) {
return [ShipType.x1]
}
else if (this.get_n_boats() === 2) {
return [ShipType.x1, ShipType.x2]
}
else if (this.get_n_boats() === 3) {
return [ShipType.x1, ShipType.x2, ShipType.x3]
}
else if (this.get_n_boats() === 4) {
return [ShipType.x1, ShipType.x2, ShipType.x3, ShipType.x4]
}
else if (this.get_n_boats() === 5) {
return [ShipType.x1, ShipType.x2, ShipType.x3, ShipType.x4, ShipType.x5]
}
}
/**
* The current state of the game.
* @private
* @type {string}
*/
current_state = GameState.ChoosingNumberOfShips
/**
* The current player.
* @private
* @type {string}
*/
current_player = Player.One
/**
* The current opponent.
* @private
* @type {string}
*/
current_opponent = Player.Two
/**
* If the current state is the PromptPlayerChange, then this is
* the state that we should move to next.
* @type {undefined|string}
*/
post_player_change_state = undefined
/**
* True if, during the current turn, the user has tried to fire a missile.
* @type {boolean}
*/
current_turn_had_missile_attempt = false
/**
* Array of functions that are called when the game state changes.
* @type {function[]}
*/
game_state_change_listeners = []
/**
* Construct a new game service. Initialize any internal states.
*/
constructor() {
// Generate empty boards for each player
for ( const player of this.players ) {
this.player_x_game_board[player] = this._build_empty_board()
this.player_x_ships[player] = []
}
}
/**
* Get the dimensions of the board as [rows, cols].
* @example const [n_rows, n_cols] = game_service.get_dimensions()
* @return {number[]}
*/
get_dimensions() {
return [this.n_rows, this.n_cols]
}
/**
* Get the player who is the focus of the current game state.
* @return {string}
*/
get_current_player() {
return this.current_player
}
/**
* Get the player who is NOT the focus of the current game state.
* @return {string}
*/
get_current_opponent() {
return this.current_opponent
}
/**
* Get the state of the current player's board, as it should appear to them.
* @return {object[][]}
*/
get_current_player_state() {
// The player can see everything about their own board, so just return it.
// Return a deep-copy, so internal state can't be modified.
return clone(this.player_x_game_board[this.current_player])
}
/**
* Get the state of the current opponent's board, as it should appear to the
* current player. Note that the current player cannot see "ship" spaces, only
* available, damaged, missed, or sunk.
* @return {object[][]}
*/
get_current_opponent_state() {
// Return a deep-copy, so internal state can't be modified.
const state = clone(this.player_x_game_board[this.current_opponent])
const hidden_states = [
GridCellState.Disabled,
GridCellState.Ship,
]
return state.map(row => {
return row.map(cell => {
if ( hidden_states.includes(cell.render) ) {
// This is a hidden state, so hide it
cell.render = GridCellState.Available
}
return cell
})
})
}
/**
* Get the states that should be shown on the victory screen.
* First element is the winner's state, second element is the loser's state.
* @return {object[][][]}
*/
get_player_victory_state(){
return [clone(this.player_x_game_board[this.current_player]), clone(this.player_x_game_board[this.current_opponent])]
}
/**
* get the "score" (the number of hits) that the
* current player has (counting sunk ships)
* @return {number}
* @private
*/
get_player_score(player) {
let score = 0
this.player_x_game_board[player].some(row => {
row.some(cell => {
if ( cell.render === GridCellState.Damaged || cell.render === GridCellState.Sunk ) {
score += 1
}
})
})
return score
}
/**
* gets the number of the boats (sunken, damaged or not) that the opponent has
* used to help keep get progress method looking clean
* @return {number}
* @private
*/
get_boat_count(player){
let boat_count = 0
this.player_x_game_board[player].some(row => {
row.some(cell => {
if ( isShipCell(cell.render) ) {
boat_count += 1
}
})
})
return boat_count
}
/**
* gets the progress (hits/total boats) that the player has
* @return {number}
* @private
*/
get_progress(player){
const boat_count = this.get_boat_count(player)
if ( boat_count !== 0 ) {
return (this.get_player_score(player) / boat_count).toFixed(2)
} else {
return 0
}
}
/**
* Get the current game state.
* @return {string}
*/
get_game_state() {
return clone(this.current_state)
}
/**
* responsible for advancing the game state
* will be consisting of
*/
advance_game_state() {
/** functions to be made that validate:
* 1) number of ships
* 2) player one placement
* 3) player two placement
* 4) player one turn
* 5) advance to player 2
* 6) player 2 turn
* 7) advance to player one
* 8) player win
*/
if (this.current_state === GameState.ChoosingNumberOfShips) {
if (this.n_boats >= 1 && this.n_boats <= 5) {
this.current_state = GameState.PromptPlayerChange;
this.post_player_change_state = GameState.PlayerSetup;
this.current_player = Player.One;
this.current_opponent = Player.Two;
} else {
throw new InvalidAdvanceStateError("Invalid Number of Boats");
}
}
else if (this.current_state === GameState.PlayerSetup) {
if (this.current_player === Player.One) {
// because the place_ship handles all the validation
// all you need to do is make sure they have placed all the appropriate ships
if ( this.get_ship_entities(this.current_player).length === this.n_boats ) {
this.current_state = GameState.PromptPlayerChange;
this.post_player_change_state = GameState.PlayerSetup;
this.current_player = Player.Two;
this.current_opponent = Player.One;
}
else{
throw new InvalidAdvanceStateError("Player One has a problem with the number of boats selected");
}
}
else if (this.current_player === Player.Two) {
if ( this.get_ship_entities(this.current_player).length === this.n_boats ) {
this.current_state = GameState.PromptPlayerChange;
this.post_player_change_state = GameState.PlayerTurn;
this.current_player = Player.One;
this.current_opponent = Player.Two;
}
else{
throw new InvalidAdvanceStateError("Player Two has a problem with the number of boats selected");
}
}
}
else if (this.current_state === GameState.PlayerTurn && this.current_player === Player.One) {
if (this.current_turn_had_missile_attempt === true) {
this.current_state = GameState.PromptPlayerChange;
this.post_player_change_state = GameState.PlayerTurn;
this.current_player = Player.Two;
this.current_opponent = Player.One;
}
else {
throw new InvalidAdvanceStateError("the player has not fired a missle");
}
}
else if (this.current_state === GameState.PlayerTurn && this.current_player === Player.Two) {
if (this.current_turn_had_missile_attempt === true) {
this.current_state = GameState.PromptPlayerChange;
this.post_player_change_state = GameState.PlayerTurn;
this.current_player = Player.One;
this.current_opponent = Player.Two;
}
else {
throw new InvalidAdvanceStateError("the player has not fired a missle");
}
}
else if ( this.current_state === GameState.PromptPlayerChange ) {
if ( !this.post_player_change_state ) {
throw new InvalidAdvanceStateError('No state to advance to after player change!')
}
this.current_state = this.post_player_change_state
this.post_player_change_state = undefined
}
let winner = this.get_winner();
if(winner) {
this.current_state = GameState.PlayerVictory;
this.current_player = winner;
this.current_opponent = this.get_other_player(winner);
}
this.current_turn_had_missile_attempt = false
this.game_state_change_listeners.forEach(fn => fn(this.current_state, false))
}
/**
* Register a handler to be called when the game state changes.
* @param {function} handler
*/
on_state_change(handler) {
this.game_state_change_listeners.push(handler)
}
/**
* Attempt to fire a missile at the current opponent at the given coordinates.
* The coordinates should be an array of [row_index, column_index] where the missile should fire.
* Returns true if the missile hit an undamaged cell of a ship.
*
* @example
* If I want to fire a missile at row 5 column 7, then:
* game_service.attempt_missile_fire([5, 7])
*
* @param {number[]} coords
* @return {boolean}
*/
attempt_missile_fire([target_row_i, target_col_i]) {
if ( this.current_turn_had_missile_attempt ) {
throw new InvalidMissileFireAttemptError('Cannot fire more than once per turn.')
} else {
this.current_turn_had_missile_attempt = true
}
const target_cell = this._get_cell_state(this.current_opponent, target_row_i, target_col_i)
if ( !isValidTargetCell(target_cell.render) ) {
this.current_turn_had_missile_attempt = false
throw new InvalidMissileFireAttemptError('Cannot fire on cell with state: ' + target_cell.render)
}
if ( target_cell.render === GridCellState.Ship ) {
// We hit an un-hit ship cell!
this._set_cell_state(this.current_opponent, target_row_i, target_col_i, GridCellState.Damaged)
// set ships to sunk where appropriate
this._sink_damaged_ships(this.current_opponent)
this._trigger_view_update()
return true
} else if ( target_cell.render === GridCellState.Available ) {
// We missed...
this._set_cell_state(this.current_opponent, target_row_i, target_col_i, GridCellState.Missed)
}
this._trigger_view_update()
return false
}
/**
* Checks the player's ships. If any are fully damaged, it flags that ship's cells
* as "sunk" rather than damaged.
* @param {string} player
* @private
*/
_sink_damaged_ships(player) {
this.get_ship_entities(player).some(ship => {
const covered_cells = this.get_covered_cells(ship.coords_one, ship.coords_two)
const all_damaged = covered_cells.every(([cell_row, cell_col]) => {
return this._get_cell_state(player, cell_row, cell_col).render === GridCellState.Damaged
})
if ( all_damaged ) {
// The entire boat was damaged, so sink it
covered_cells.some(([cell_row, cell_col]) => {
this._set_cell_state(player, cell_row, cell_col, GridCellState.Sunk)
})
}
})
}
/**
* Attempt to place a ship of the given type at the given coordinates.
* Throws an InvalidShipPlacementError if the coordinates are invalid.
* Coordinates should be [row_index, column_index] of either end of the ship.
*
* @example
* If I am placing a 1x3 ship and I want it to be in row 3 column 2 horizontal
* to row 3 column 4, then I would call:
* game_service.place_ship(ShipType.x3, [3,2], [3,4])
*
* @param {string} ship_type
* @param {number[]} coords_one
* @param {number[]} coords_two
*/
place_ship(ship_type, coords_one, coords_two) {
// make sure the coordinates are valid for the given ship type
this.validate_coordinates(ship_type, coords_one, coords_two)
// get the ships for the current player
const player_ships = this.get_ship_entities(this.current_player)
// make sure they don't already have this ship type
const have_ship_type = player_ships.some(ship => ship.ship_type === ship_type)
if ( have_ship_type )
throw new InvalidShipPlacementError('A ship with this type has already been placed.')
// make sure they don't already have too many
if ( player_ships.length >= this.n_boats )
throw new InvalidShipPlacementError('This player cannot place any more ships.')
// place the ship
this.player_x_ships[this.current_player].push({ ship_type, coords_one, coords_two })
// mark the cells as having a ship in them
this.get_covered_cells(coords_one, coords_two).some(([row_i, col_i]) => {
this._set_cell_state(this.current_player, row_i, col_i, GridCellState.Ship)
})
// refresh the view
this._trigger_view_update()
}
/**
* Get an array of cell coordinates that are covered by a ship that spans
* the given coordinates.
*
* @example
* If a ship goes from row 1 column 1 to row 4 column 1, then I can get
* the coordinates of all cells covered by that ship using:
* game_service.get_covered_cells([1,1], [4,1])
* Which would return [[1,1], [2,1], [3,1], [4,1]].
*
* @param {number[]} coords_one
* @param {number[]} coords_two
* @return {number[][]}
*/
get_covered_cells(coords_one, coords_two) {
const [row_one, col_one] = coords_one
const [row_two, col_two] = coords_two
const [left_col, right_col] = [Math.min(col_one, col_two), Math.max(col_one, col_two)]
const [top_row, bottom_row] = [Math.min(row_one, row_two), Math.max(row_one, row_two)]
const is_horizontal = top_row === bottom_row
if ( is_horizontal ) {
return Array((right_col - left_col) + 1).fill('').map((_, i) => {
return [top_row, i + left_col]
})
} else {
return Array((bottom_row - top_row) + 1).fill('').map((_, i) => {
return [i + top_row, left_col]
})
}
}
/**
* Validate the given coordinates for the given ship type.
* Throws an InvalidShipPlacementError if the coordinates are invalid.
* Coordinates should be [row_index, column_index] of either end of the ship.
*
* @example
* If I am placing a 1x3 ship and I want it to be in row 3 column 2 horizontal
* to row 3 column 4, then I would call:
* game_service.validate_coordinates(ShipType.x3, [3,2], [3,4])
*
* @param {string} ship_type
* @param {number[]} coords_one
* @param {number[]} coords_two
*/
validate_coordinates(ship_type, coords_one, coords_two) {
if ( !isShipType(ship_type) ) throw new InvalidShipPlacementError('Invalid ship type: '+ship_type)
const ship_length = this.get_ship_length(ship_type)
const [row_one, col_one] = coords_one
const [row_two, col_two] = coords_two
const [left_col, right_col] = [Math.min(col_one, col_two), Math.max(col_one, col_two)]
const [top_row, bottom_row] = [Math.min(row_one, row_two), Math.max(row_one, row_two)]
const is_horizontal = top_row === bottom_row
const ship_cells = this.get_ship_cells(this.current_player)
const placement_cells = []
if ( is_horizontal ) {
// Make sure the input length matches the given ship type
if ( (right_col - left_col) !== (ship_length - 1) )
throw new InvalidShipPlacementError('Invalid coordinates: ship length is invalid')
Array(ship_length).fill('').map((_, i) => {
placement_cells.push([top_row, i + left_col])
})
} else {
// Make sure the input length matches the given ship type
if ( (bottom_row - top_row) !== (ship_length - 1) )
throw new InvalidShipPlacementError('Invalid coordinates: ship length is invalid')
Array(ship_length).fill('').map((_, i) => {
placement_cells.push([i + top_row, left_col])
})
}
// Make sure none of the placement cells overlap with existing ships
const has_overlap = ship_cells.some(([ship_row, ship_col]) => {
return placement_cells.some(([placement_row, placement_col]) => {
return ship_row === placement_row && ship_col === placement_col
})
})
if ( has_overlap )
throw new InvalidShipPlacementError('Invalid coordinates: ship overlaps with others')
}
/**
* Get the number of cells the given ship type should occupy.
* @param {string} ship_type
* @return {number}
*/
get_ship_length(ship_type) {
if ( ship_type === ShipType.x1 ) return 1
if ( ship_type === ShipType.x2 ) return 2
if ( ship_type === ShipType.x3 ) return 3
if ( ship_type === ShipType.x4 ) return 4
if ( ship_type === ShipType.x5 ) return 5
}
/**
* Get the coordinates of all cells that have ships in them, for the given player.
* @param {string} player
* @return {number[]}
*/
get_ship_cells(player) {
const cells = []
this.player_x_game_board[player].some((row, row_i) => {
row.some((col, col_i) => {
if ( isShipCell(col.render) ) {
cells.push([row_i, col_i])
}
})
})
return cells
}
/**
* If there is a winner, this will return the Player that won.
* If no winner has been decided yet, will return undefined.
* @return {string|undefined}
*/
get_winner() {
const [player_1, player_2] = this.players
// Make sure to sink any fully-damaged ships
this._sink_damaged_ships(player_1)
const player_1_ship_cells = this.get_ship_cells(player_1)
const player_1_loses = (
(player_1_ship_cells.length > 0)
&& player_1_ship_cells.every(cell => this._get_cell_state(player_1, cell[0], cell[1]).render === GridCellState.Sunk)
)
if ( player_1_loses ) return player_2
// Make sure to sink any fully-damaged ships
this._sink_damaged_ships(player_2)
const player_2_ship_cells = this.get_ship_cells(player_2)
const player_2_loses = (
(player_2_ship_cells.length > 0)
&& player_2_ship_cells.every(cell => this._get_cell_state(player_2, cell[0], cell[1]).render === GridCellState.Sunk)
)
if ( player_2_loses ) return player_2
}
/**
* Returns the other player.
* @param {string} player
* @return {string}
*/
get_other_player(player) {
if ( player === Player.One ) return Player.Two
else if ( player === Player.Two ) return Player.One
}
/**
* Given a Player type, return the display value of that player.
* @param {string} player
* @return {string}
*/
get_player_display(player) {
if ( player === Player.One ) return 'Player 1'
else if ( player === Player.Two ) return 'Player 2'
}
/**
* Get an array of ship entities for the given player.
* @param {string} player
* @return {object[]}
*/
get_ship_entities(player) {
return clone(this.player_x_ships[player])
}
/**
* Build an empty structure of grid cells.
* @return {object[][]}
* @private
*/
_build_empty_board() {
return Array(this.n_rows).fill('').map(_ => {
return Array(this.n_cols).fill('').map(_ => {
return {
render: GridCellState.Available,
}
})
})
}
/**
* Set the state of the cell at the given coordinates on the player's board
* to the specified state.
* @param {string} player
* @param {number} row_i
* @param {number} col_i
* @param {string} state
* @private
*/
_set_cell_state(player, row_i, col_i, state) {
this.player_x_game_board[player][row_i][col_i].render = state
}
/**
* Get the state of the cell at the given coordinates on the player's board.
* @param {string} player
* @param {number} row_i
* @param {number} col_i
* @return {object}
* @private
*/
_get_cell_state(player, row_i, col_i) {
return this.player_x_game_board[player][row_i][col_i]
}
/**
* Force a view update without changing the current state.
* @private
*/
_trigger_view_update() {
this.game_state_change_listeners.forEach(fn => fn(this.current_state, true))
}
}
// Export a single instance, so it can be shared by all files
// To use the game state service, you should do:
// import game_service from './services/GameState.service.js'
const game_service = new GameStateService()
export default game_service