// Programs: run a command, read what it printed, look at the environment.
//
//   import proc
//   code := proc.run("make")                  the exit code; what the command prints goes to the screen
//   text := try proc.output("git describe")   what the command printed; an error if it failed
//   proc.env("HOME", "/")                     an environment variable, or the second value if it is not set
import "stdlib.h"
import "unistd.h"
import "time.h"

// run a command; its output goes to the screen. Gives its exit code.
fn run(str command) -> int {
    return shell(command)
}

// run a command and give what it printed. Fails, with its output as the message, if it exits with an error.
fn output(str command) -> str! {
    tmp := "/tmp/finch_out_" + str(getpid()) + "_" + str(int(time(null)))
    code := shell("(" + command + ") > '" + tmp + "' 2>&1")
    text := read_file(tmp) or ""
    delete_file(tmp)
    if code != 0 {
        return error("'" + command + "' exited with code " + str(code) + ": " + text.trim())
    }
    return text
}

fn env(str name, str fallback) -> str {
    v := getenv(name)
    if v.len == 0 {
        return fallback
    }
    return v
}

fn pid() -> int {
    return int(getpid())
}

// the folder the program is running in
fn cwd() -> str {
    []char buf
    for i in 0..4096 {
        buf.push(char(0))
    }
    getcwd(buf.ptr, 4096)
    return str(buf.ptr)
}