import { Card } from '../cards/Card';
import { PlayerId } from './GameState';

export enum ActionType {
    /** Lay an attacking card — either the opening card of a turn or an addition. */
    Attack = 'attack',
    /** Beat one attacking card. */
    Defend = 'defend',
    /** Give up the defence and pick the whole table up. */
    Take = 'take',
    /** Declare that nothing more will be added this turn. */
    Pass = 'pass',
}

export interface AttackAction {
    readonly type: ActionType.Attack;
    readonly player: PlayerId;
    readonly card: Card;
}

export interface DefendAction {
    readonly type: ActionType.Defend;
    readonly player: PlayerId;
    readonly card: Card;
    /** Index into `GameState.table` of the slot being beaten. */
    readonly slot: number;
}

export interface TakeAction {
    readonly type: ActionType.Take;
    readonly player: PlayerId;
}

export interface PassAction {
    readonly type: ActionType.Pass;
    readonly player: PlayerId;
}

export type Action = AttackAction | DefendAction | TakeAction | PassAction;

export const Actions = {
    attack(player: PlayerId, card: Card): AttackAction {
        return { type: ActionType.Attack, player, card };
    },
    defend(player: PlayerId, card: Card, slot: number): DefendAction {
        return { type: ActionType.Defend, player, card, slot };
    },
    take(player: PlayerId): TakeAction {
        return { type: ActionType.Take, player };
    },
    pass(player: PlayerId): PassAction {
        return { type: ActionType.Pass, player };
    },
};

export function describeAction(action: Action): string {
    switch (action.type) {
        case ActionType.Attack: return `${action.player} attacks with ${action.card.code}`;
        case ActionType.Defend: return `${action.player} beats slot ${action.slot} with ${action.card.code}`;
        case ActionType.Take: return `${action.player} takes`;
        case ActionType.Pass: return `${action.player} passes`;
    }
}

/** Thrown when an action is not permitted in the current state. */
export class IllegalActionError extends Error {
    constructor(action: Action, reason: string) {
        super(`Illegal action (${describeAction(action)}): ${reason}`);
        this.name = 'IllegalActionError';
    }
}