import assert from 'node:assert/strict';
import { spawnSync } from 'node:child_process';
import { mkdtemp, rm, writeFile } from 'node:fs/promises';
import os from 'node:os';
import path from 'node:path';
import { fileURLToPath } from 'node:url';
import { after, before, test } from 'node:test';

import {
    DEFAULT_HEAD_PATH,
    compareBaselineDirection,
    formatDirectionResult,
    parseArgs,
} from './check-baseline-direction.mjs';

const scriptPath = fileURLToPath(
    new URL('./check-baseline-direction.mjs', import.meta.url)
);

const file = (initialBytes, extra = {}) => ({
    version: 1,
    journeys: {
        launch: {
            'renderer.initialBytes': { value: initialBytes, unit: 'bytes' },
            ...extra,
        },
    },
});

let workDir;
before(async () => {
    workDir = await mkdtemp(
        path.join(os.tmpdir(), 'check-baseline-direction-')
    );
});
after(async () => {
    await rm(workDir, { recursive: true, force: true });
});

test('an unchanged or lowered baseline passes', () => {
    const same = compareBaselineDirection({ base: file(100), head: file(100) });
    assert.deepEqual(same.failures, []);
    assert.deepEqual(same.unchanged, ['launch/renderer.initialBytes']);

    const lowered = compareBaselineDirection({
        base: file(100),
        head: file(90),
    });
    assert.deepEqual(lowered.failures, []);
    assert.match(lowered.lowered[0], /100 -> 90 bytes/);
});

test('a raised baseline fails with both values', () => {
    const result = compareBaselineDirection({
        base: file(100),
        head: file(101),
    });
    assert.equal(result.failures.length, 1);
    assert.match(
        result.failures[0],
        /raised from 100 to 101 bytes\. Baselines only move down/
    );
});

test('a removed baseline fails; a new one is reported and passes', () => {
    const removed = compareBaselineDirection({
        base: file(100, { cdTicks: { value: 5 } }),
        head: file(100),
    });
    assert.equal(removed.failures.length, 1);
    assert.match(
        removed.failures[0],
        /launch\/cdTicks: baseline 5 was removed/
    );

    const added = compareBaselineDirection({
        base: file(100),
        head: file(100, { cdTicks: { value: 5 } }),
    });
    assert.deepEqual(added.failures, []);
    assert.deepEqual(added.added, ['launch/cdTicks']);
});

test('a widened or newly added tolerance fails even when the value went down', () => {
    const widened = compareBaselineDirection({
        base: file(100, {
            firstCardMs: { value: 100, unit: 'ms', toleranceRatio: 1.1 },
        }),
        head: file(100, {
            firstCardMs: { value: 99, unit: 'ms', toleranceRatio: 2 },
        }),
    });
    assert.equal(widened.failures.length, 1);
    assert.match(
        widened.failures[0],
        /firstCardMs: toleranceRatio widened from 1\.1 to 2/
    );

    const added = compareBaselineDirection({
        base: file(100),
        head: file(100, undefined) && {
            version: 1,
            journeys: {
                launch: {
                    'renderer.initialBytes': {
                        value: 100,
                        unit: 'bytes',
                        toleranceRatio: 1.25,
                    },
                },
            },
        },
    });
    assert.equal(added.failures.length, 1);
    assert.match(added.failures[0], /toleranceRatio widened from 1 to 1\.25/);
});

test('the enforced limit is what is compared for wall-clock entries', () => {
    const narrowed = compareBaselineDirection({
        base: file(100, {
            firstCardMs: { value: 100, unit: 'ms', toleranceRatio: 1.25 },
        }),
        head: file(100, {
            firstCardMs: { value: 110, unit: 'ms', toleranceRatio: 1 },
        }),
    });
    assert.deepEqual(narrowed.failures, []);
    assert.match(narrowed.lowered[0], /firstCardMs: 125 -> 110 ms/);

    const raisedLimit = compareBaselineDirection({
        base: file(100, {
            firstCardMs: { value: 100, unit: 'ms', toleranceRatio: 1.25 },
        }),
        head: file(100, {
            firstCardMs: { value: 130, unit: 'ms', toleranceRatio: 1.25 },
        }),
    });
    assert.equal(raisedLimit.failures.length, 1);
    assert.match(
        raisedLimit.failures[0],
        /firstCardMs: baseline raised from 125 to 162\.5 ms/
    );
});

test('a widened or newly added slack fails; a narrowed one lowers the limit', () => {
    const withSlack = (value, slack) => ({
        version: 1,
        journeys: {
            launch: {
                'renderer.initialBytes': { value, unit: 'bytes', slack },
            },
        },
    });

    const added = compareBaselineDirection({
        base: file(100),
        head: withSlack(90, 20),
    });
    assert.equal(added.failures.length, 1);
    assert.match(
        added.failures[0],
        /renderer\.initialBytes: slack widened from 0 to 20 bytes/
    );

    const widened = compareBaselineDirection({
        base: withSlack(100, 10),
        head: withSlack(95, 12),
    });
    assert.equal(widened.failures.length, 1);
    assert.match(widened.failures[0], /slack widened from 10 to 12 bytes/);

    const narrowed = compareBaselineDirection({
        base: withSlack(100, 10),
        head: withSlack(100, 4),
    });
    assert.deepEqual(narrowed.failures, []);
    assert.match(narrowed.lowered[0], /110 -> 104 bytes/);

    const raised = compareBaselineDirection({
        base: withSlack(100, 10),
        head: withSlack(101, 10),
    });
    assert.match(raised.failures[0], /baseline raised from 110 to 111 bytes/);
    assert.match(raised.failures[0], /perf-baseline-increase label/);
});

test('a counter value raised behind narrower slack still fails', () => {
    const withSlack = (value, slack) => ({
        version: 1,
        journeys: {
            launch: {
                'renderer.initialBytes': { value, unit: 'bytes', slack },
            },
        },
    });
    const result = compareBaselineDirection({
        base: withSlack(100, 10),
        head: withSlack(105, 0),
    });
    assert.equal(result.failures.length, 1);
    assert.deepEqual(result.lowered, []);
    assert.match(
        result.failures[0],
        /renderer\.initialBytes: baseline value raised from 100 to 105 bytes while slack narrowed from 10 to 0/
    );

    const allowed = compareBaselineDirection({
        base: withSlack(100, 10),
        head: withSlack(105, 0),
        allowIncrease: true,
    });
    assert.deepEqual(allowed.failures, []);
    assert.equal(allowed.allowed.length, 1);
});

test('switching an entry between counter and wall-clock fails', () => {
    const counterToWallClock = compareBaselineDirection({
        base: file(100, { x: { value: 100, slack: 10 } }),
        head: file(100, { x: { value: 105, toleranceRatio: 1 } }),
    });
    assert.equal(counterToWallClock.failures.length, 1);
    assert.deepEqual(counterToWallClock.lowered, []);
    assert.match(
        counterToWallClock.failures[0],
        /launch\/x: changed from a counter entry to a wall-clock entry/
    );

    const wallClockToCounter = compareBaselineDirection({
        base: file(100, { x: { value: 100, toleranceRatio: 1.25 } }),
        head: file(100, { x: { value: 90 } }),
    });
    assert.equal(wallClockToCounter.failures.length, 1);
    assert.match(
        wallClockToCounter.failures[0],
        /changed from a wall-clock entry to a counter entry/
    );

    const allowed = compareBaselineDirection({
        base: file(100, { x: { value: 100, slack: 10 } }),
        head: file(100, { x: { value: 105, toleranceRatio: 1 } }),
        allowIncrease: true,
    });
    assert.deepEqual(allowed.failures, []);
    assert.equal(allowed.allowed.length, 1);
});

test('allowIncrease reports every weakening as allowed instead of failing', () => {
    const result = compareBaselineDirection({
        base: file(100, { cdTicks: { value: 5 } }),
        head: {
            version: 1,
            journeys: {
                launch: {
                    'renderer.initialBytes': {
                        value: 120,
                        unit: 'bytes',
                        slack: 8,
                    },
                },
            },
        },
        allowIncrease: true,
    });
    assert.deepEqual(result.failures, []);
    assert.equal(result.allowed.length, 2);
    assert.match(result.allowed[0], /slack widened from 0 to 8 bytes/);
    assert.match(result.allowed[1], /cdTicks: baseline 5 was removed/);
    assert.match(
        formatDirectionResult(result),
        /^ALLOWED {2}launch\/renderer\.initialBytes.*\nALLOWED {2}launch\/cdTicks.*\nBaseline direction OK: 0 unchanged, 0 lowered, 0 added, 2 weakened with the perf-baseline-increase label\.$/
    );

    const lowered = compareBaselineDirection({
        base: file(100),
        head: file(90),
        allowIncrease: true,
    });
    assert.deepEqual(lowered.allowed, []);
    assert.equal(lowered.lowered.length, 1);
});

test('an empty target-branch file cannot be weakened', () => {
    const result = compareBaselineDirection({
        base: { journeys: {} },
        head: file(100),
    });
    assert.deepEqual(result.failures, []);
    assert.deepEqual(result.added, ['launch/renderer.initialBytes']);
});

test('formats the outcome', () => {
    assert.match(
        formatDirectionResult(
            compareBaselineDirection({ base: file(100), head: file(90) })
        ),
        /^lowered {2}launch\/renderer\.initialBytes: 100 -> 90 bytes\.\nBaseline direction OK: 0 unchanged, 1 lowered, 0 added\.$/
    );
    assert.match(
        formatDirectionResult(
            compareBaselineDirection({ base: file(100), head: file(200) })
        ),
        /^FAIL {5}launch.*\nBaseline direction check failed: 1 entries raised or removed\.$/
    );
});

test('parses arguments and requires --base', () => {
    assert.deepEqual(parseArgs(['--base', 'b.json']), {
        base: 'b.json',
        head: DEFAULT_HEAD_PATH,
        allowIncrease: false,
    });
    assert.deepEqual(
        parseArgs(['--', '--base=b.json', '--head=h.json', '--allow-increase']),
        {
            base: 'b.json',
            head: 'h.json',
            allowIncrease: true,
        }
    );
    assert.throws(
        () => parseArgs([]),
        /--base <target-branch-journey-baselines\.json> is required/
    );
    assert.throws(() => parseArgs(['--base']), /Missing value for --base/);
    assert.throws(
        () => parseArgs(['--base', 'b', '--force']),
        /Unknown argument: --force/
    );
});

async function runCli(base, head, extraArgs = []) {
    const basePath =
        base === null
            ? path.join(workDir, 'absent.json')
            : path.join(workDir, `base-${Math.random()}.json`);
    const headPath = path.join(workDir, `head-${Math.random()}.json`);
    if (base !== null) await writeFile(basePath, JSON.stringify(base));
    await writeFile(headPath, JSON.stringify(head));
    return spawnSync(
        process.execPath,
        [scriptPath, '--base', basePath, '--head', headPath, ...extraArgs],
        {
            encoding: 'utf8',
        }
    );
}

test('CLI exits 0 for a lowered baseline, 1 for a raised one, 0 for a raised one with --allow-increase, 0 when the target branch has no file', async () => {
    const lowered = await runCli(file(100), file(90));
    assert.equal(lowered.status, 0, lowered.stderr);
    assert.match(lowered.stdout, /Baseline direction OK/);

    const raised = await runCli(file(100), file(101));
    assert.equal(raised.status, 1);
    assert.match(
        raised.stderr,
        /FAIL {5}launch\/renderer\.initialBytes: baseline raised/
    );

    const allowed = await runCli(file(100), file(101), ['--allow-increase']);
    assert.equal(allowed.status, 0, allowed.stderr);
    assert.match(
        allowed.stdout,
        /ALLOWED {2}launch\/renderer\.initialBytes: baseline raised/
    );

    const noBase = await runCli(null, file(100));
    assert.equal(noBase.status, 0, noBase.stderr);
    assert.match(noBase.stdout, /nothing to weaken/);
});