// Copyright (C) 2026 Viorel Munteanu
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

#include "process.h"

#include <sys/wait.h>
#include <unistd.h>

#include <cstring>

#include <fmt/ranges.h>
#include <spdlog/spdlog.h>

ProcessResult run_process(const std::vector<std::string>& argv) {
    spdlog::debug("running external command: {}", fmt::join(argv, " "));

    int stdout_pipe[2];
    if (pipe(stdout_pipe) != 0) {
        return {-1, ""};
    }

    pid_t pid = fork();
    if (pid < 0) {
        close(stdout_pipe[0]);
        close(stdout_pipe[1]);
        return {-1, ""};
    }

    if (pid == 0) {
        close(stdout_pipe[0]);
        dup2(stdout_pipe[1], STDOUT_FILENO);
        close(stdout_pipe[1]);

        std::vector<char*> c_argv;
        c_argv.reserve(argv.size() + 1);
        for (const auto& arg : argv) {
            c_argv.push_back(const_cast<char*>(arg.c_str()));
        }
        c_argv.push_back(nullptr);

        execvp(c_argv[0], c_argv.data());
        const char* msg = "run_process: execvp failed\n";
        write(STDERR_FILENO, msg, std::strlen(msg));
        _exit(127);
    }

    close(stdout_pipe[1]);

    std::string output;
    char buffer[4096];
    ssize_t n;
    while ((n = read(stdout_pipe[0], buffer, sizeof(buffer))) > 0) {
        output.append(buffer, static_cast<size_t>(n));
    }
    close(stdout_pipe[0]);

    int status = 0;
    waitpid(pid, &status, 0);

    int exit_code = WIFEXITED(status) ? WEXITSTATUS(status) : -1;
    if (exit_code != 0) {
        spdlog::warn("external command failed (exit code {}): {}", exit_code, fmt::join(argv, " "));
    }
    return {exit_code, output};
}