import { describe, expect, it } from 'vitest';
import { SCENES, sceneCells } from './lessons';
import { frozen, hasLegalMove, inCheck, kindOf, legalMovesFrom, movesFrom, playOn, square } from './board';
import { CALLOUTS, TOLD_MOVES, toldStates } from './told';

describe('the lessons', () => {
	it('every scene’s move is legal for the side to move, and only the asked-for moves count', () => {
		for (const scene of SCENES) {
			const cells = sceneCells(scene);
			for (const [from, to] of scene.moves) {
				const legal = legalMovesFrom(cells, square(from), 'printed');
				expect(legal, `${scene.id}: ${from} to ${to}`).toContain(square(to));
			}
			// The piece asked for is the player's.
			for (const [from] of scene.moves) expect(cells[square(from)][0], scene.id).toBe(scene.side === 'gold' ? 'g' : 's');
			// The scene draws every board its move touches.
			for (const [from, to] of scene.moves) {
				expect(scene.levels, scene.id).toContain(Number(from[0]));
				expect(scene.levels, scene.id).toContain(Number(to[0]));
			}
		}
	});

	it('the scenes do what their words say', () => {
		const at = (id: string) => SCENES.find((s) => s.id === id)!;
		const play = (id: string) => {
			const s = at(id);
			const cells = sceneCells(s);
			const [from, to] = s.moves[0];
			return { cells, after: playOn(cells, square(from), square(to)), s };
		};
		// The Warrior's step is blocked and its capture is not.
		expect(movesFrom(sceneCells(at('warrior')), square('2c2'))).toEqual([square('2d3')]);
		// The Hero leaps the Warrior and takes the Mage.
		expect(play('hero').after.captured).toBe('M');
		// The Mage comes down two boards onto the Basilisk.
		expect(play('mage').after.captured).toBe('B');
		// The Paladin vaults over the Dwarf at 1c5.
		expect(play('paladin').after.captured).toBe('D');
		// The Sylph's dive and the Dragon's strike take what they say.
		expect(play('sylph').after.captured).toBe('O');
		const dragon = play('dragon');
		expect(dragon.after.afar).toBe(true);
		expect(dragon.after.captured).toBe('M');
		expect(dragon.after.cells[square('3c4')]).toBe('gR');
		// The Basilisk's arrival freezes the Mage above.
		const basilisk = play('basilisk');
		expect(frozen(basilisk.after.cells, square('2e4'))).toBe(true);
		expect(movesFrom(basilisk.after.cells, square('2e4'))).toEqual([]);
		// The Elemental climbs onto the Thief.
		expect(play('elemental').after.captured).toBe('T');
		// The King is in check before it moves, and out of it after either move; up or down leaves it off the land.
		const king = sceneCells(at('king'));
		expect(inCheck(king, 'gold')).toBe(true);
		expect(legalMovesFrom(king, square('2g1'), 'printed').sort()).toEqual([square('1g1'), square('2f1'), square('2h1'), square('3g1')].sort());
		// The last scene is mate in one by either listed move, and by no other.
		const mate = play('mate');
		for (const [from, to] of mate.s.moves) {
			const after = playOn(mate.cells, square(from), square(to)).cells;
			expect(inCheck(after, 'scarlet'), `${from} to ${to}`).toBe(true);
			expect(hasLegalMove(after, 'scarlet', 'printed'), `${from} to ${to}`).toBe(false);
		}
		const listed = new Set(mate.s.moves.map(([a, b]) => `${square(a)}-${square(b)}`));
		for (const to of legalMovesFrom(mate.cells, square('2a1'), 'printed')) {
			if (listed.has(`${square('2a1')}-${to}`)) continue;
			const after = playOn(mate.cells, square('2a1'), to).cells;
			expect(inCheck(after, 'scarlet') && !hasLegalMove(after, 'scarlet', 'printed'), `unlisted mate by the Oliphant to ${to}`).toBe(false);
		}
		expect(kindOf(mate.cells[square('2d4')])).toBe('K');
		expect(frozen(mate.cells, square('2d4'))).toBe(true);
	});
});

describe('the game told', () => {
	it('plays through the engine from the opening to a checkmate, and every callout sits on a move', () => {
		const states = toldStates();
		expect(states).toHaveLength(TOLD_MOVES.length + 1);
		const last = states[states.length - 1];
		expect(last.end).toBe('mate');
		expect(last.over?.winner).toBe('A');
		for (const n of Object.keys(CALLOUTS).map(Number)) expect(n).toBeLessThanOrEqual(TOLD_MOVES.length);
		// The things the callouts say happened.
		expect(last.moves[8].captured).toBe('R');
		expect(last.moves[16].kind).toBe('B');
		expect(last.moves[20].captured).toBe('H');
		expect(last.moves[23].captured).toBe('H');
		expect(last.moves[26].captured).toBe('S');
		expect(last.moves[26].check).toBe(true);
	});
});