const { test } = require('node:test');
const assert = require('node:assert');
const fs = require('node:fs');
const path = require('node:path');
const os = require('node:os');
const { loadSpriteLock, mergeSpriteLock, serializeSpriteLock } = require('../src/lock-sprite');

test('loadSpriteLock: missing file -> null', () => {
    const result = loadSpriteLock('/nonexistent/lock.json');
    assert.strictEqual(result, null);
});

test('loadSpriteLock: reads valid lock', () => {
    const tmp = fs.mkdtempSync(path.join(os.tmpdir(), 'lock-test-'));
    const lockPath = path.join(tmp, 'lock.json');
    fs.writeFileSync(lockPath, JSON.stringify({
        atlas_id: 'tcbasics',
        version: 1,
        aliases: ['bed1', 'bench1'],
        sources: { bed1: 'Bed1.png', bench1: 'Bench1.png' },
    }));
    const lock = loadSpriteLock(lockPath);
    assert.strictEqual(lock.atlas_id, 'tcbasics');
    assert.deepStrictEqual(lock.aliases, ['bed1', 'bench1']);
});

test('mergeSpriteLock: no existing lock -> all new', () => {
    const sources = [
        { alias: 'bed1',  sourceFile: 'Bed1.png' },
        { alias: 'bench1',sourceFile: 'Bench1.png' },
    ];
    const { merged, removed } = mergeSpriteLock(null, sources);
    assert.deepStrictEqual(merged.aliases, ['bed1', 'bench1']);
    assert.deepStrictEqual(removed, []);
});

test('mergeSpriteLock: existing alias preserved; new appended', () => {
    const existing = {
        atlas_id: 'tcbasics',
        version: 1,
        aliases: ['bed1'],
        sources: { bed1: 'Bed1.png' },
    };
    const sources = [
        { alias: 'bed1',   sourceFile: 'Bed1.png' },
        { alias: 'bench1', sourceFile: 'Bench1.png' },
    ];
    const { merged, removed } = mergeSpriteLock(existing, sources);
    assert.deepStrictEqual(merged.aliases, ['bed1', 'bench1']);
    assert.deepStrictEqual(removed, []);
});

test('mergeSpriteLock: removed alias appears in `removed`', () => {
    const existing = {
        atlas_id: 'tcbasics',
        version: 1,
        aliases: ['bed1', 'bench1'],
        sources: { bed1: 'Bed1.png', bench1: 'Bench1.png' },
    };
    const sources = [
        { alias: 'bed1', sourceFile: 'Bed1.png' },
    ];
    const { merged, removed } = mergeSpriteLock(existing, sources);
    assert.deepStrictEqual(merged.aliases, ['bed1']);
    assert.deepStrictEqual(removed, ['bench1']);
});

test('serializeSpriteLock: stable JSON shape', () => {
    const lock = {
        atlas_id: 'tcbasics',
        version: 1,
        aliases: ['bed1'],
        sources: { bed1: 'Bed1.png' },
    };
    const json = serializeSpriteLock(lock);
    const parsed = JSON.parse(json);
    assert.deepStrictEqual(parsed, lock);
    // Trailing newline for POSIX-friendliness
    assert.ok(json.endsWith('\n'));
});