#!/usr/bin/env bun

/**
 * SLSA Provenance generation script for CI/CD
 *
 * Generates an in-toto attestation with SLSA v1.0 provenance predicate
 * for a published package. Intended to be called from the publish pipeline
 * after a successful npm publish.
 *
 * Reads build metadata from GitLab CI environment variables and writes
 * the provenance statement to a `.provenance.json` file alongside the artifact.
 *
 * Usage:
 *   bun scripts/generate-provenance.ts --package @suaveplan/utils --version 1.2.3 --digest abc123
 *   bun scripts/generate-provenance.ts --package @suaveplan/utils --version 1.2.3 --digest abc123 --output ./provenance/
 *
 * Environment variables (auto-detected in GitLab CI):
 *   CI_COMMIT_SHA           - Git commit SHA
 *   CI_PROJECT_URL          - Repository URL
 *   CI_COMMIT_REF_NAME      - Branch or tag name
 *   CI_RUNNER_ID            - Runner identifier
 *   CI_JOB_ID               - Job identifier
 *   CI_JOB_STARTED_AT       - Job start timestamp
 *   CI_PIPELINE_ID          - Pipeline identifier
 */

import { createHash } from "node:crypto";
import { mkdir, stat, writeFile } from "node:fs/promises";
import { join } from "node:path";
import { CONFIG } from "./lib/config.js";

const ROOT_DIR = CONFIG.paths.root;

interface CliOptions {
    packageName: string;
    version: string;
    digest: string;
    outputDir?: string;
}

function parseArgs(): CliOptions {
    const args = process.argv.slice(2);
    let packageName = "";
    let version = "";
    let digest = "";
    let outputDir: string | undefined;

    for (let i = 0; i < args.length; i++) {
        const arg = args[i];
        if (arg === "--package" && i + 1 < args.length) {
            packageName = args[++i];
        } else if (arg.startsWith("--package=")) {
            packageName = arg.slice(10);
        } else if (arg === "--version" && i + 1 < args.length) {
            version = args[++i];
        } else if (arg.startsWith("--version=")) {
            version = arg.slice(10);
        } else if (arg === "--digest" && i + 1 < args.length) {
            digest = args[++i];
        } else if (arg.startsWith("--digest=")) {
            digest = arg.slice(9);
        } else if (arg === "--output" && i + 1 < args.length) {
            outputDir = args[++i];
        } else if (arg.startsWith("--output=")) {
            outputDir = arg.slice(9);
        }
    }

    if (!packageName || !version || !digest) {
        console.error(
            "Usage: bun scripts/generate-provenance.ts --package <name> --version <ver> --digest <sha256>"
        );
        process.exit(1);
    }

    return { packageName, version, digest, outputDir };
}

function getGitLabEnv() {
    return {
        commitSha: process.env.CI_COMMIT_SHA ?? "unknown",
        projectUrl:
            process.env.CI_PROJECT_URL ??
            "https://gitlab.fq.io/suaveplan/monorepo",
        refName: process.env.CI_COMMIT_REF_NAME ?? "unknown",
        runnerId: process.env.CI_RUNNER_ID ?? "local",
        jobId: process.env.CI_JOB_ID ?? `local-${Date.now()}`,
        jobStartedAt: process.env.CI_JOB_STARTED_AT ?? new Date().toISOString(),
        pipelineId: process.env.CI_PIPELINE_ID ?? "local",
        isCI: !!(process.env.CI || process.env.GITLAB_CI),
    };
}

function generateProvenanceStatement(
    options: CliOptions,
    env: ReturnType<typeof getGitLabEnv>
) {
    const buildType = "https://suaveplan.app/slsa/build-type/bun-monorepo/v1";
    const encodedName = options.packageName.replace("@", "%40");
    const subjectUri = `pkg:npm/${encodedName}@${options.version}`;
    const builderId = `${env.projectUrl}/-/runners/${env.runnerId}`;
    const invocationId = `${env.projectUrl}/-/pipelines/${env.pipelineId}/jobs/${env.jobId}`;

    return {
        _type: "https://in-toto.io/Statement/v1",
        subject: [
            {
                uri: subjectUri,
                digest: { sha256: options.digest },
                name: options.packageName,
            },
        ],
        predicateType: "https://slsa.dev/provenance/v1",
        predicate: {
            buildDefinition: {
                buildType,
                externalParameters: {
                    repository: env.projectUrl,
                    ref: `refs/heads/${env.refName}`,
                },
                internalParameters: {
                    environment: env.isCI ? "gitlab-ci" : "local",
                    resolvedDependencies: [
                        {
                            uri: `git+${env.projectUrl}@refs/heads/${env.refName}`,
                            digest: { sha256: env.commitSha },
                            name: "source",
                        },
                    ],
                },
                resolvedDependencies: [
                    {
                        uri: `git+${env.projectUrl}@refs/heads/${env.refName}`,
                        digest: { sha256: env.commitSha },
                        name: "source",
                    },
                ],
            },
            runDetails: {
                builder: {
                    id: builderId,
                    version: {
                        bun:
                            typeof Bun !== "undefined"
                                ? Bun.version
                                : "unknown",
                    },
                },
                metadata: {
                    invocationId,
                    startedOn: env.jobStartedAt,
                    finishedOn: new Date().toISOString(),
                },
            },
        },
    };
}

async function main() {
    const options = parseArgs();
    const env = getGitLabEnv();

    console.log(
        `Generating SLSA provenance for ${options.packageName}@${options.version}`
    );
    console.log(`  Commit: ${env.commitSha}`);
    console.log(`  Builder: ${env.projectUrl}/-/runners/${env.runnerId}`);
    console.log(`  CI: ${env.isCI ? "yes" : "no (local)"}`);

    const statement = generateProvenanceStatement(options, env);
    const json = JSON.stringify(statement, null, 2);

    // Compute digest of the provenance itself
    const provenanceDigest = createHash("sha256").update(json).digest("hex");

    const outputDir = options.outputDir
        ? join(ROOT_DIR, options.outputDir)
        : join(ROOT_DIR, "provenance");

    try {
        await stat(outputDir);
    } catch {
        await mkdir(outputDir, { recursive: true });
    }

    const safeName = options.packageName.replace(/[/@]/g, "_");
    const filename = `${safeName}-${options.version}.provenance.json`;
    const outputPath = join(outputDir, filename);

    await writeFile(outputPath, json);

    console.log(`  Output: ${outputPath}`);
    console.log(`  Provenance digest: ${provenanceDigest}`);
}

main().catch(console.error);