module os

// - ProcessState.not_started - the process has not yet started
// - ProcessState.running - the process is currently running
// - ProcessState.stopped - the process was running, but was stopped temporarily
// - ProcessState.exited - the process has finished/exited
// - ProcessState.aborted - the process was terminated by a signal
// - ProcessState.closed - the process resources like opened file descriptors were freed/discarded, final state.
pub enum ProcessState {
    not_started
    running
    stopped
    exited
    aborted
    closed
}

@[heap]
pub struct Process {
pub mut:
    filename         string // the process's command file path
    pid              int    // the PID of the process
    code             int          = -1           // the exit code of the process, != -1 *only* when status is .exited *and* the process was not aborted
    status           ProcessState = .not_started // the current status of the process
    err              string   // if the process fails, contains the reason why
    args             []string // the arguments that the command takes
    work_folder      string   // the initial working folder of the process. When '', reuse the same folder as the parent process.
    env_is_custom    bool     // true, when the environment was customized with .set_environment
    env              []string // the environment with which the process was started  (list of 'var=val')
    use_stdio_ctl    bool     // when true, then you can use p.stdin_write(), p.stdout_slurp() and p.stderr_slurp()
    use_pgroup       bool     // when true, the process will create a new process group, enabling .signal_pgkill()
    stdio_fd         [3]int   // the stdio file descriptors for the child process, used only by the nix implementation
    wdata            voidptr  // the WProcess; used only by the windows implementation
    create_no_window bool     // sets a value indicating whether to start the process in a new window, The default is false; used only by the windows implementation
}

// new_process - create a new process descriptor.
// Note: new does NOT start the new process.
// That is done because you may want to customize it first,
// by calling different set_ methods on it.
// In order to start it, call p.run() or p.wait()
pub fn new_process(filename string) &Process {
    return &Process{
        filename: filename
        stdio_fd: [-1, -1, -1]!
    }
}

// set_args - set the arguments for the new process.
pub fn (mut p Process) set_args(pargs []string) {
    if p.status != .not_started {
        return
    }
    p.args = pargs
    return
}

// set_work_folder - set the initial working folder for the new process.
// If you do not set it, it will reuse the current working folder of the parent process.
pub fn (mut p Process) set_work_folder(path string) {
    if p.status != .not_started {
        return
    }
    p.work_folder = real_path(path)
    return
}

// set_environment - set a custom environment variable mapping for the new process.
pub fn (mut p Process) set_environment(envs map[string]string) {
    if p.status != .not_started {
        return
    }
    p.env_is_custom = true
    p.env = []string{}
    for k, v in envs {
        p.env << '${k}=${v}'
    }
    return
}