// Tests unitaires du domaine « partie », avec un faux moteur (ADR 0007,
// point 7) : journal, rejeu, branches, déroulement des tours et du videau.
//
// Copyright (C) 2026 les auteurs d'Ustagammon.
// Licence : GPLv3 ou ultérieure (voir LICENSE).

import assert from "node:assert/strict";
import { test } from "node:test";
import type {
    Board,
    CubeDecision,
    Engine,
    HalfMovesCheck,
    Move,
} from "../src/domain/game/engine.js";
import { appendEvent, currentLine, EMPTY_JOURNAL, goBackTo } from "../src/domain/game/events.js";
import { Game } from "../src/domain/game/game.js";
import { formatHalfMoves, parseHalfMoves, START_POSITION } from "../src/domain/game/position.js";
import { fixedDice } from "../src/domain/game/roll.js";
import { replay } from "../src/domain/game/state.js";

/** Un faux moteur : chaque réponse est réglable, et les positions sont des
 * textes sans signification. */
function fakeEngine(overrides: Partial<Engine> = {}): Engine {
    const move: Move = {
        notation: "8/5 6/5",
        halfMoves: parseHalfMoves("8/5 6/5"),
        position: "AFTER",
    };
    const notOver: Board = {
        onRoll: { points: [], bar: 0, off: 0, pipCount: 0 },
        opponent: { points: [], bar: 0, off: 0, pipCount: 0 },
        swappedPosition: "SWAPPED",
        result: null,
    };
    const noDouble: CubeDecision = { available: true, double: false, take: true };
    return {
        legalMoves: async () => [move],
        bestMove: async () => move,
        cubeDecision: async () => noDouble,
        checkHalfMoves: async (_position, _roll, halfMoves): Promise<HalfMovesCheck> => {
            const text = formatHalfMoves(halfMoves);
            if (text === "8/5") {
                return { valid: true, complete: false, position: "HALF" };
            }
            if (text === "8/5 6/5") {
                return { valid: true, complete: true, position: "AFTER" };
            }
            return { valid: false, complete: false, position: null };
        },
        board: async () => notOver,
        ...overrides,
    };
}

test("le jet d'ouverture se relance en cas d'égalité, puis le plus fort dé commence", () => {
    const game = Game.start(fakeEngine(), { dice: fixedDice([4, 4, 2, 5]) });
    const rolls = game.events.filter((e) => e.type === "DiceRolled");
    assert.deepEqual(
        rolls.map((e) => e.roll),
        [
            [4, 4],
            [2, 5],
        ],
    );
    assert.equal(game.state.turn, "computer");
    assert.equal(game.state.phase, "moving");
    assert.deepEqual(game.state.roll, [2, 5]);
    assert.equal(game.state.position, START_POSITION);
});

test("un coup se saisit demi-coup par demi-coup ; un demi-coup refusé ne change rien", async () => {
    const game = Game.start(fakeEngine(), { dice: fixedDice([3, 1]) });
    assert.equal(await game.playHalfMove({ from: 13, to: 12 }), false);
    assert.equal(game.events.length, 2);
    assert.equal(await game.playHalfMove({ from: 8, to: 5 }), true);
    assert.equal(game.displayedPosition, "HALF");
    assert.deepEqual(game.pendingHalfMoves, [{ from: 8, to: 5 }]);
    assert.equal(await game.playHalfMove({ from: 6, to: 5 }), true);

    const last = game.events.at(-1);
    assert.equal(last?.type, "MovePlayed");
    assert.deepEqual(game.pendingHalfMoves, []);
    assert.equal(game.state.turn, "computer");
    assert.equal(game.state.phase, "rolling");
    assert.equal(game.state.position, "SWAPPED");
});

test("sans coup possible, le tour passe", async () => {
    const engine = fakeEngine({ legalMoves: async () => [] });
    const game = Game.start(engine, {
        dice: fixedDice([6, 6]),
        setup: { position: "BLOCKED", firstTurn: "player" },
    });
    await game.roll();
    const last = game.events.at(-1);
    assert.ok(last?.type === "MovePlayed");
    assert.deepEqual(last.halfMoves, []);
    assert.equal(game.state.turn, "computer");
});

test("l'ordinateur double si le moteur le recommande ; le joueur prend", async () => {
    const engine = fakeEngine({
        cubeDecision: async () => ({ available: true, double: true, take: true }),
    });
    const game = Game.start(engine, { setup: { position: "X", firstTurn: "computer" } });
    await game.playComputerTurn();
    assert.equal(game.state.phase, "doubled");
    game.take();
    assert.deepEqual(game.state.cube, { value: 2, owner: "player" });
    assert.equal(game.state.phase, "rolling");
    assert.equal(game.state.turn, "computer");
});

test("le joueur passe : il perd la partie à la valeur d'avant le double", async () => {
    const engine = fakeEngine({
        cubeDecision: async () => ({ available: true, double: true, take: true }),
    });
    const game = Game.start(engine, {
        setup: { position: "X", firstTurn: "computer", cube: { value: 2, owner: "computer" } },
    });
    await game.playComputerTurn();
    game.drop();
    assert.equal(game.state.phase, "over");
    assert.deepEqual(game.state.result, { winner: "computer", kind: "single", points: 2 });
});

test("le joueur double : l'ordinateur passe si le moteur le dit", async () => {
    const engine = fakeEngine({
        cubeDecision: async () => ({ available: true, double: true, take: false }),
    });
    const game = Game.start(engine, { setup: { position: "X", firstTurn: "player" } });
    await game.double();
    assert.deepEqual(
        game.events.slice(-3).map((e) => e.type),
        ["CubeOffered", "CubeDropped", "GameEnded"],
    );
    assert.deepEqual(game.state.result, { winner: "player", kind: "single", points: 1 });
});

test("le joueur ne peut pas doubler si le videau est chez l'ordinateur", async () => {
    const engine = fakeEngine({
        cubeDecision: async () => ({ available: false, double: false, take: true }),
    });
    const game = Game.start(engine, {
        setup: { position: "X", firstTurn: "player", cube: { value: 2, owner: "computer" } },
    });
    await assert.rejects(game.double(), /videau/);
    assert.equal(game.events.length, 1);
});

test("la fin de partie vient du moteur : gagnant, sorte et points", async () => {
    const engine = fakeEngine({
        board: async () => ({
            onRoll: { points: [], bar: 0, off: 15, pipCount: 0 },
            opponent: { points: [], bar: 0, off: 0, pipCount: 100 },
            swappedPosition: "SWAPPED",
            result: { winner: "onRoll", kind: "gammon", points: 2 },
        }),
    });
    const game = Game.start(engine, {
        setup: { position: "X", firstTurn: "computer" },
        dice: fixedDice([2, 1]),
    });
    await game.playComputerTurn();
    assert.deepEqual(game.state.result, { winner: "computer", kind: "gammon", points: 2 });
    assert.throws(() => game.take(), /action impossible/);
});

test("annuler repart du parent ; l'action suivante ouvre une branche", async () => {
    const game = Game.start(fakeEngine(), { dice: fixedDice([3, 1, 6, 5, 4, 2]) });
    await game.playHalfMove({ from: 8, to: 5 });
    await game.playHalfMove({ from: 6, to: 5 });
    const played = game.events.at(-1);
    assert.equal(played?.type, "MovePlayed");

    game.undo();
    assert.equal(game.state.phase, "moving");
    assert.equal(game.state.turn, "player");
    await game.playHalfMove({ from: 8, to: 5 });
    await game.playHalfMove({ from: 6, to: 5 });

    // Deux coups accrochés au même jet : l'ancien reste dans le journal.
    const moves = game.journal.events.filter((e) => e.type === "MovePlayed");
    assert.equal(moves.length, 2);
    assert.equal(moves[0]?.parent, moves[1]?.parent);
    assert.notEqual(game.events.at(-1)?.id, played?.id);

    game.goBackTo(played?.id ?? "");
    assert.equal(game.events.at(-1)?.id, played?.id);
});

test("les événements sont immuables et versionnés ; le rejeu est déterministe", () => {
    let journal = appendEvent(EMPTY_JOURNAL, {
        type: "GameStarted",
        position: START_POSITION,
        cube: { value: 1, owner: null },
        firstTurn: null,
    });
    journal = appendEvent(journal, { type: "DiceRolled", side: null, roll: [5, 2] });
    const [started, rolled] = currentLine(journal);
    assert.equal(started?.version, 1);
    assert.equal(started?.parent, null);
    assert.equal(rolled?.parent, started?.id);
    assert.throws(() => {
        (rolled as { parent: string | null }).parent = null;
    }, TypeError);
    assert.deepEqual(replay(currentLine(journal)), replay(currentLine(journal)));
    assert.equal(replay(currentLine(goBackTo(journal, "1"))).phase, "opening");
});

test("lecture et écriture des demi-coups", () => {
    assert.deepEqual(parseHalfMoves("bar/22 6/off"), [
        { from: 25, to: 22 },
        { from: 6, to: 0 },
    ]);
    assert.equal(formatHalfMoves(parseHalfMoves(" 8/5  6/5 ")), "8/5 6/5");
    assert.throws(() => parseHalfMoves("8-5"), /mal formé/);
    assert.throws(() => parseHalfMoves("30/5"), /case invalide/);
});

test("une partie se reprend depuis son journal ; un journal d'une autre version est refusé", async () => {
    const game = Game.start(fakeEngine(), { dice: fixedDice([3, 1]) });
    await game.playHalfMove({ from: 8, to: 5 });
    await game.playHalfMove({ from: 6, to: 5 });
    const saved = JSON.parse(JSON.stringify(game.journal));

    const resumed = Game.resume(fakeEngine(), saved);
    assert.deepEqual(resumed.state, game.state);
    assert.deepEqual(resumed.events, game.events);

    const other = { ...saved, events: saved.events.map((e: object) => ({ ...e, version: 99 })) };
    assert.throws(() => Game.resume(fakeEngine(), other), /version/);
    assert.throws(() => Game.resume(fakeEngine(), EMPTY_JOURNAL), /mal formé/);
    assert.throws(() => Game.resume(fakeEngine(), { ...saved, head: "inconnu" }), /introuvable/);
});

test("le droit de doubler vient du moteur, seulement avant de lancer les dés", async () => {
    let available = true;
    const engine = fakeEngine({
        cubeDecision: async () => ({ available, double: false, take: true }),
    });
    const game = Game.start(engine, {
        dice: fixedDice([3, 1]),
        setup: { position: "X", firstTurn: "player" },
    });
    assert.equal(await game.canDouble(), true);
    available = false;
    assert.equal(await game.canDouble(), false);
    available = true;
    await game.roll();
    assert.equal(game.state.phase, "moving");
    assert.equal(await game.canDouble(), false);
});

test("le plateau affiché est donné du point de vue de chaque camp", async () => {
    const side = (pipCount: number) => ({ points: [], bar: 0, off: 0, pipCount });
    const engine = fakeEngine({
        board: async () => ({
            onRoll: side(1),
            opponent: side(2),
            swappedPosition: "SWAPPED",
            result: null,
        }),
    });
    const playerTurn = Game.start(engine, { setup: { position: "X", firstTurn: "player" } });
    const sides = await playerTurn.displayedBoard();
    assert.equal(sides.player.pipCount, 1);
    assert.equal(sides.computer.pipCount, 2);
    const computerTurn = Game.start(engine, { setup: { position: "X", firstTurn: "computer" } });
    const swapped = await computerTurn.displayedBoard();
    assert.equal(swapped.player.pipCount, 2);
    assert.equal(swapped.computer.pipCount, 1);
});