/*!
 * @license
 * Copyright © 2005-2025 Hyland Software, Inc. and its affiliates. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Malware checker - queries OSV and GitHub Advisory databases for known malware.
 */

const MALWARE_KEYWORDS = ['malware', 'malicious', 'compromised', 'supply chain', 'backdoor'];
const OSV_API_URL = 'https://api.osv.dev/v1/querybatch';
const OSV_SINGLE_API_URL = 'https://api.osv.dev/v1/query';
const GITHUB_API_URL = 'https://api.github.com/advisories?ecosystem=npm&type=malware&per_page=100';
const REQUEST_TIMEOUT_MS = 10000;
const BATCH_SIZE = 1000;

// ============================================================================
// UTILITY FUNCTIONS
// ============================================================================

function containsMalwareKeyword(text) {
    const lowerText = text.toLowerCase();
    return MALWARE_KEYWORDS.some(keyword => lowerText.includes(keyword));
}

function splitIntoBatches(items, batchSize) {
    const batches = [];
    for (let index = 0; index < items.length; index += batchSize) {
        batches.push(items.slice(index, index + batchSize));
    }
    return batches;
}

function deduplicateFindings(findings) {
    return findings.filter((finding, index, array) =>
        array.findIndex(other =>
            other.name === finding.name && other.version === finding.version
        ) === index
    );
}

// ============================================================================
// OSV API
// ============================================================================

function buildOsvQuery(packageName, packageVersion) {
    return {
        package: { name: packageName, ecosystem: 'npm' },
        version: packageVersion
    };
}

function buildOsvBatchPayload(packages) {
    return {
        queries: packages.map(pkg => buildOsvQuery(pkg.name, pkg.version))
    };
}

function extractMalwareFromOsvVulnerability(vulnerability) {
    const summaryText = [vulnerability.summary || '', vulnerability.details || ''].join(' ');

    if (containsMalwareKeyword(summaryText)) {
        return vulnerability.summary || 'Malware detected';
    }

    return null;
}

async function fetchOsvBatch(packages) {
    const response = await fetch(OSV_API_URL, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(buildOsvBatchPayload(packages)),
        signal: AbortSignal.timeout(REQUEST_TIMEOUT_MS * 3)
    });

    if (!response.ok) {
        return null;
    }

    return response.json();
}

async function fetchOsvSingle(packageName, packageVersion) {
    const response = await fetch(OSV_SINGLE_API_URL, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(buildOsvQuery(packageName, packageVersion)),
        signal: AbortSignal.timeout(REQUEST_TIMEOUT_MS)
    });

    if (!response.ok) {
        return null;
    }

    return response.json();
}

function processBatchResults(batchResults, packages) {
    const findings = [];
    const results = batchResults.results || [];

    for (let index = 0; index < results.length; index++) {
        const vulnerabilities = results[index].vulns || [];

        for (const vulnerability of vulnerabilities) {
            const malwareReason = extractMalwareFromOsvVulnerability(vulnerability);

            if (malwareReason) {
                findings.push({
                    name: packages[index].name,
                    version: packages[index].version,
                    reason: malwareReason,
                    source: 'OSV'
                });
            }
        }
    }

    return findings;
}

export async function checkPackagesWithOsv(packages) {
    if (!packages.length) {
        return [];
    }

    const allFindings = [];
    const batches = splitIntoBatches(packages, BATCH_SIZE);

    for (const batch of batches) {
        try {
            const batchResults = await fetchOsvBatch(batch);

            if (batchResults) {
                const findings = processBatchResults(batchResults, batch);
                allFindings.push(...findings);
            }
        } catch {
            // Network errors are non-fatal
        }
    }

    return allFindings;
}

export async function checkSinglePackageWithOsv(packageName, packageVersion) {
    try {
        const data = await fetchOsvSingle(packageName, packageVersion);

        if (!data) {
            return null;
        }

        for (const vulnerability of data.vulns || []) {
            const malwareReason = extractMalwareFromOsvVulnerability(vulnerability);

            if (malwareReason) {
                return malwareReason;
            }
        }
    } catch {
        // Network errors are non-fatal
    }

    return null;
}

// ============================================================================
// GITHUB ADVISORY API
// ============================================================================

async function fetchGitHubAdvisories() {
    const response = await fetch(GITHUB_API_URL, {
        headers: { 'Accept': 'application/vnd.github+json' },
        signal: AbortSignal.timeout(REQUEST_TIMEOUT_MS)
    });

    if (!response.ok) {
        return null;
    }

    return response.json();
}

function extractMalwarePackageNames(advisories) {
    const malwarePackageNames = new Set();

    for (const advisory of advisories) {
        const vulnerabilities = advisory.vulnerabilities || [];

        for (const vulnerability of vulnerabilities) {
            const packageName = vulnerability.package?.name;

            if (packageName) {
                malwarePackageNames.add(packageName);
            }
        }
    }

    return malwarePackageNames;
}

export async function checkPackagesWithGitHub(packages) {
    if (!packages.length) {
        return [];
    }

    const findings = [];

    try {
        const advisories = await fetchGitHubAdvisories();

        if (!advisories) {
            return findings;
        }

        const malwarePackageNames = extractMalwarePackageNames(advisories);

        for (const pkg of packages) {
            if (malwarePackageNames.has(pkg.name)) {
                findings.push({
                    name: pkg.name,
                    version: pkg.version,
                    reason: 'Known malware package',
                    source: 'GitHub Advisory'
                });
            }
        }
    } catch {
        // Network errors are non-fatal
    }

    return findings;
}

export async function checkSinglePackageWithGitHub(packageName) {
    try {
        const advisories = await fetchGitHubAdvisories();

        if (!advisories) {
            return null;
        }

        for (const advisory of advisories) {
            const vulnerabilities = advisory.vulnerabilities || [];

            for (const vulnerability of vulnerabilities) {
                if (vulnerability.package?.name === packageName) {
                    return advisory.summary || 'Malware advisory';
                }
            }
        }
    } catch {
        // Network errors are non-fatal
    }

    return null;
}

// ============================================================================
// COMBINED CHECK
// ============================================================================

export async function checkPackagesForMalware(packages) {
    const [osvFindings, githubFindings] = await Promise.all([
        checkPackagesWithOsv(packages),
        checkPackagesWithGitHub(packages)
    ]);

    const allFindings = [...osvFindings, ...githubFindings];
    return deduplicateFindings(allFindings);
}

export async function checkSinglePackageForMalware(packageName, packageVersion) {
    const [osvResult, githubResult] = await Promise.all([
        checkSinglePackageWithOsv(packageName, packageVersion),
        checkSinglePackageWithGitHub(packageName)
    ]);

    return osvResult || githubResult || null;
}