import child_process from "child_process"
import { PlatformPath } from "path"
import path from "path"

// FIXME: these imports basically looks ugly.
import { LLVM_EXTRACT, PREFIX, SYSROOT_PREFIX, FLANG } from "./environment";
import { CompilerCommands } from "./commands";


/**
 * Helper function to generate output options for the linker.
 * @param exe Executable file name.
 * @returns Array of options to be passed to the linker.
 */
function driverOutput(exe: string): string[] {
    return ["-o", exe];
}


export function functionList(module: string) {
    let result: string[] = [];

    // Split the LLVM module string by lines
    const lines = module.split('\n')

    lines.forEach(line => {
        if (line.startsWith('define')) {
            let begin = line.indexOf('@');
            let end = line.indexOf('(');
            result.push(line.substring(begin + 1, end).trim());
        }
    });
    return result;
}

/**
 * Extract one function using llvm-extract
 */
export async function extract(options: CompilerCommands.ExtractOptions) {
    let process = child_process.spawn(
        LLVM_EXTRACT,
        CompilerCommands.extractCommand(options),
        { stdio: "inherit" }
    )
    const exitcode = await new Promise((resolve, reject) => { process.on('close', resolve) })
    return exitcode
}


/**
 * Links objects into an executable using specified environment variables and paths.
 * @param objects Array of object files to link.
 * @param exe Executable file name.
 */
export async function link(objects: string[], exe: string) {

    // Set up environment variables
    const linkenv = { ...process.env };
    linkenv.LD_LIBRARY_PATH = [
        path.join(PREFIX, 'lib'),
        path.join(SYSROOT_PREFIX, 'lib'),
        path.join(SYSROOT_PREFIX, 'usr', 'lib')
    ].join(':');

    // Construct link command
    const linkcmd = [
        FLANG,
        ...objects,
        "-L", path.join(PREFIX, 'lib'),
        // TODO: Implement rpath logic here if needed
        ...driverOutput(exe)
    ];

    // Execute the link command
    child_process.spawn(linkcmd[0], linkcmd.slice(1), {
        stdio: 'inherit',
        env: linkenv
    });

    return new Promise((resolve, reject) => { process.on('close', resolve) })
}