// runtime/env.el — environment and process
// Covers: environment variables, command-line args, process exit, in-process
// state store, UUID generation, and list convenience helpers.

// env — read an environment variable.  Returns "" if the variable is not set.
fn env(key: String) -> String {
    return __env_get(key)
}

// args — command-line arguments as a list of strings.
// __args_json returns a JSON array (e.g. ["prog","arg1","arg2"]).
// The list is built by iterating over the array.
fn args() -> [String] {
    let json: String = __args_json()
    let n: Int = json_array_len(json)
    let result: [String] = el_list_empty()
    let i: Int = 0
    while i < n {
        let item: String = json_array_get_string(json, i)
        let result = el_list_append(result, item)
        let i = i + 1
    }
    return result
}

// exit_program — terminate the process with the given exit code.
fn exit_program(code: Int) {
    __exit_program(code)
}

// ── List convenience helpers ───────────────────────────────────────────────

// get — index into a list.  Thin alias for el_list_get used throughout the
// El stdlib so call sites read like `get(lst, i)` rather than the verbose form.
fn get(lst: [String], i: Int) -> String {
    return el_list_get(lst, i)
}

// len — length of a list.
fn len(lst: [String]) -> Int {
    return el_list_len(lst)
}

// ── In-process key-value state store ──────────────────────────────────────

// state_set — store a string value under key.
fn state_set(key: String, val: String) {
    __state_set(key, val)
}

// state_get — retrieve value for key; returns "" if key not present.
fn state_get(key: String) -> String {
    return __state_get(key)
}

// state_del — remove key from the store.
fn state_del(key: String) {
    __state_del(key)
}

// state_keys — all keys currently in the store as a JSON array string.
fn state_keys() -> String {
    return __state_keys()
}

// ── DHARMA runtime helpers ─────────────────────────────────────────────────

// config — read a configuration value from the environment.
// Returns "" if the variable is not set. Alias for env().
fn config(key: String) -> String {
    return __env_get(key)
}

// log_info — write an [INFO] log line to stdout.
fn log_info(msg: String) {
    __println("[INFO] " + msg)
}

// log_warn — write a [WARN] log line to stdout.
fn log_warn(msg: String) {
    __println("[WARN] " + msg)
}

// list_len — return the number of elements in a list. Alias for el_list_len.
fn list_len(lst: [String]) -> Int {
    return el_list_len(lst)
}

// list_get — return the element at index i in a list. Alias for el_list_get.
fn list_get(lst: [String], i: Int) -> String {
    return el_list_get(lst, i)
}

// ── UUID generation ────────────────────────────────────────────────────────

// uuid_new — generate a new random UUID v4.
fn uuid_new() -> String {
    return __uuid_v4()
}

// uuid_v4 — alias for uuid_new(); explicit version name for callers that
// need to be precise about the UUID variant.
fn uuid_v4() -> String {
    return __uuid_v4()
}