#!/usr/bin/env node

import {
    existsSync,
    mkdirSync,
    readFileSync,
    readdirSync,
    statSync,
    writeFileSync,
} from 'node:fs';
import path from 'node:path';
import process from 'node:process';

import {
    describeShardReports,
    findPlaywrightJsonReports,
    loadPlaywrightReports,
    verifyShardReports,
} from './e2e-shard-reports.mjs';

const workspaceRoot = process.cwd();
const args = process.argv.slice(2);
const projectArg = valueFor('--project');
const inputArg = valueFor('--input');
const policy = JSON.parse(
    readFileSync(path.join(workspaceRoot, 'tools/coverage/coverage-policy.json'), 'utf8')
);
const outputDirArg = valueFor('--output-dir');
const outputDir = path.resolve(
    workspaceRoot,
    outputDirArg ?? policy.reporting.e2eSummaryDir
);
const outputDirLabel = outputDirArg ?? policy.reporting.e2eSummaryDir;

function valueFor(flag) {
    const prefixed = args.find((arg) => arg.startsWith(`${flag}=`));
    if (prefixed) {
        return prefixed.slice(flag.length + 1);
    }
    const index = args.indexOf(flag);
    return index >= 0 ? args[index + 1] : undefined;
}

function listFiles(directory, predicate) {
    if (!existsSync(directory)) {
        return [];
    }
    const files = [];
    for (const entry of readdirSync(directory)) {
        const fullPath = path.join(directory, entry);
        const stats = statSync(fullPath);
        if (stats.isDirectory()) {
            files.push(...listFiles(fullPath, predicate));
        } else if (predicate(fullPath)) {
            files.push(fullPath);
        }
    }
    return files;
}

function normalizeTag(tag) {
    const normalized = tag.startsWith('@') ? tag : `@${tag}`;
    return normalized.toLowerCase();
}

function tagsFromTitle(title) {
    return Array.from(
        new Set((title.match(/@[a-z0-9-]+/gi) ?? []).map(normalizeTag).sort())
    );
}

function fail(message) {
    console.error(`e2e-semantic-summary: ${message}`);
    if (process.env.GITHUB_STEP_SUMMARY) {
        writeFileSync(
            process.env.GITHUB_STEP_SUMMARY,
            `\n> **E2E semantic summary not written:** ${message}\n`,
            { flag: 'a' }
        );
    }
    process.exit(1);
}

const FAILURE_STATUSES = new Set(['failed', 'timedOut']);
// A spec runs once per Playwright project (browser). Flaky outranks skipped so
// a retried test in one browser is not hidden by a skip in another.
const STATUS_PRECEDENCE = ['failed', 'flaky', 'skipped'];

// Playwright retries a failing test and records every attempt. Only a final
// pass turns earlier failures into flaky, which Playwright itself does not
// count as unexpected; any other ending after a failure stays failed.
function attemptsStatus(results) {
    const statuses = results.map((result) => result.status);
    const finalStatus = statuses.at(-1);
    if (finalStatus === undefined) {
        return 'unknown';
    }
    const anyFailure = statuses.some((status) => FAILURE_STATUSES.has(status));
    if (finalStatus === 'passed') {
        return anyFailure ? 'flaky' : 'passed';
    }
    return anyFailure ? 'failed' : finalStatus;
}

function specStatus(spec) {
    const statuses = (spec.tests ?? []).map((test) => attemptsStatus(test.results ?? []));
    return (
        STATUS_PRECEDENCE.find((status) => statuses.includes(status)) ?? statuses[0] ?? 'unknown'
    );
}

function collectFromPlaywrightJson(report, projectName) {
    const tests = [];

    function walkSuite(suite, inheritedFile) {
        const file = suite.file ?? inheritedFile;
        for (const spec of suite.specs ?? []) {
            const title = [...(spec.titlePath ?? []), spec.title].filter(Boolean).join(' ');
            const tags = new Set([
                ...(spec.tags ?? []).map(normalizeTag),
                ...tagsFromTitle(title),
            ]);
            const status = specStatus(spec);

            tests.push({
                project: projectName,
                file,
                title,
                status,
                tags: Array.from(tags).sort(),
            });
        }

        for (const child of suite.suites ?? []) {
            walkSuite(child, file);
        }
    }

    for (const suite of report.suites ?? []) {
        walkSuite(suite, suite.file);
    }

    return tests;
}

function collectFromSource(projectName) {
    const root =
        projectName === 'electron-backend-e2e'
            ? 'apps/electron-backend-e2e/src'
            : 'apps/web-e2e/src';
    const files = listFiles(path.join(workspaceRoot, root), (file) => file.endsWith('.e2e.ts'));
    const tests = [];

    for (const file of files) {
        const relativeFile = path.relative(workspaceRoot, file);
        const contents = readFileSync(file, 'utf8');
        const regex = /\btest(?:\.describe)?\s*\(\s*(['"`])([\s\S]*?)\1/g;
        for (const match of contents.matchAll(regex)) {
            const title = match[2].replace(/\s+/g, ' ').trim();
            const tags = tagsFromTitle(title);
            if (tags.length > 0) {
                tests.push({
                    project: projectName,
                    file: relativeFile,
                    title,
                    status: 'not-run',
                    tags,
                });
            }
        }
    }

    return tests;
}

function defaultInputFor(projectName) {
    return path.join(workspaceRoot, 'dist/test-results', projectName, 'results.json');
}

/**
 * `--output-dir` overrides the policy's summary directory so several runs
 * (one per OS in CI) can be summarized side by side in one job.
 *
 * `--input` may name one Playwright JSON report or a directory that holds the
 * `results.json` of every shard (as downloaded from the per-shard CI
 * artifacts). An explicit input that does not exist, a directory without any
 * report, or an incomplete or duplicated shard set aborts instead of writing
 * a partial summary. Only the implicit default falls back to scanning the
 * spec sources.
 */
function resolveReportPaths(projectName) {
    const inputPath = inputArg
        ? path.resolve(workspaceRoot, inputArg)
        : defaultInputFor(projectName);

    if (!existsSync(inputPath)) {
        if (inputArg) {
            fail(`Playwright JSON report input does not exist: ${inputPath}`);
        }
        return [];
    }
    if (!statSync(inputPath).isDirectory()) {
        return [inputPath];
    }
    const found = findPlaywrightJsonReports(inputPath);
    if (found.length === 0) {
        fail(`no Playwright JSON reports (results.json) found under ${inputPath}`);
    }
    return found;
}

function collectTests(projectName) {
    const reportPaths = resolveReportPaths(projectName);
    if (reportPaths.length === 0) {
        return { tests: collectFromSource(projectName), reports: [] };
    }

    const reports = loadPlaywrightReports(reportPaths);
    const verification = verifyShardReports(reports);
    if (!verification.ok) {
        fail(
            `${projectName} reports do not form one complete run: ${verification.problems.join('; ')}`
        );
    }

    return {
        tests: reports.flatMap((entry) =>
            collectFromPlaywrightJson(entry.report, projectName)
        ),
        reports,
    };
}

function statusCounts(tests) {
    return tests.reduce((counts, test) => {
        counts[test.status] = (counts[test.status] ?? 0) + 1;
        return counts;
    }, {});
}

function tagCounts(tests) {
    const counts = {};
    for (const test of tests) {
        for (const tag of test.tags) {
            counts[tag] = (counts[tag] ?? 0) + 1;
        }
    }
    return counts;
}

function journeyMatches(journey, tests) {
    return tests.filter(
        (test) =>
            journey.projects.includes(test.project) &&
            journey.matchAnyTags.some((tag) => test.tags.includes(tag))
    );
}

function markdownFor(projectName, tests, reportsLabel) {
    const counts = statusCounts(tests);
    const countsText = Object.entries(counts)
        .map(([status, count]) => `${status}: ${count}`)
        .join(', ');
    const tagRows = Object.entries(tagCounts(tests))
        .sort(([left], [right]) => left.localeCompare(right))
        .map(([tag, count]) => `| ${tag} | ${count} |`)
        .join('\n');
    const journeys = policy.e2eSemanticCoverage.criticalJourneys
        .filter((journey) => !projectName || journey.projects.includes(projectName))
        .map((journey) => {
            const matches = journeyMatches(journey, tests);
            const failed = matches.some((test) => test.status === 'failed');
            const status = matches.length === 0 ? 'missing' : failed ? 'failing' : 'covered';
            return `| ${journey.name} | ${journey.matchAnyTags.join(', ')} | ${matches.length} | ${status} |`;
        })
        .join('\n');

    return `# E2E Semantic Coverage${projectName ? `: ${projectName}` : ''}

Source: ${tests.some((test) => test.status === 'not-run') ? 'spec source scan' : 'Playwright JSON report'}

Reports: ${reportsLabel}

Total tracked tests: ${tests.length}

Statuses: ${countsText || 'none'}

## Tags

| Tag | Tests |
| --- | ---: |
${tagRows || '| _none_ | 0 |'}

## Critical Journeys

| Journey | Matching tags | Tests | Status |
| --- | --- | ---: | --- |
${journeys || '| _none_ | _n/a_ | 0 | missing |'}
`;
}

const projects = projectArg ? [projectArg] : ['web-e2e', 'electron-backend-e2e'];
const collected = projects.map((projectName) => ({
    projectName,
    ...collectTests(projectName),
}));
const allTests = collected.flatMap((entry) => entry.tests);
const reportsLabel = collected
    .map((entry) =>
        projectArg
            ? describeShardReports(entry.reports)
            : `${entry.projectName}: ${describeShardReports(entry.reports)}`
    )
    .join('; ');

mkdirSync(outputDir, { recursive: true });

if (projectArg) {
    const content = markdownFor(projectArg, allTests, reportsLabel);
    writeFileSync(path.join(outputDir, `${projectArg}-semantic-summary.md`), content);
    writeFileSync(
        path.join(outputDir, `${projectArg}-semantic-summary.json`),
        `${JSON.stringify(allTests, null, 4)}\n`
    );
    if (process.env.GITHUB_STEP_SUMMARY) {
        writeFileSync(process.env.GITHUB_STEP_SUMMARY, `\n${content}\n`, { flag: 'a' });
    }
    console.log(`Wrote ${outputDirLabel}/${projectArg}-semantic-summary.md`);
} else {
    const content = markdownFor(undefined, allTests, reportsLabel);
    writeFileSync(path.join(outputDir, 'semantic-summary.md'), content);
    writeFileSync(
        path.join(outputDir, 'semantic-summary.json'),
        `${JSON.stringify(allTests, null, 4)}\n`
    );
    if (process.env.GITHUB_STEP_SUMMARY) {
        writeFileSync(process.env.GITHUB_STEP_SUMMARY, `\n${content}\n`, { flag: 'a' });
    }
    console.log(`Wrote ${outputDirLabel}/semantic-summary.md`);
}