#!/usr/bin/env bash
# Shared argument parsing for bash tool scripts.
# Tools receive a JSON object on stdin.
#
# Usage:
#   source "${XDG_CONFIG_HOME:-$HOME/.config}/ollie/tools/_lib/args.sh"
#   path=$(arg_require "path")
#   start=$(arg_get "start" "")
#
# Requires: jq

# Read stdin JSON into a variable (once)
_ARGS_JSON=$(cat)
[ -z "$_ARGS_JSON" ] && _ARGS_JSON='{}'

# Get a required argument. Exits with error if missing/null.
arg_require() {
    local key="$1"
    local val
    val=$(echo "$_ARGS_JSON" | jq -r --arg k "$key" '.[$k] // empty')
    if [ -z "$val" ]; then
        echo "error: missing required argument: $key" >&2
        exit 1
    fi
    echo "$val"
}

# Get an optional argument with default.
arg_get() {
    local key="$1"
    local default="${2:-}"
    local val
    val=$(echo "$_ARGS_JSON" | jq -r --arg k "$key" '.[$k] // empty')
    if [ -z "$val" ]; then
        echo "$default"
    else
        echo "$val"
    fi
}

# Get a boolean argument (returns "true" or "false").
arg_bool() {
    local key="$1"
    local default="${2:-false}"
    local val
    val=$(echo "$_ARGS_JSON" | jq -r --arg k "$key" '.[$k] // empty')
    case "$val" in
        true|1|yes) echo "true" ;;
        false|0|no|"") echo "$default" ;;
        *) echo "$default" ;;
    esac
}

# Get raw JSON value for a key.
arg_json() {
    local key="$1"
    echo "$_ARGS_JSON" | jq --arg k "$key" '.[$k]'
}

# Get the full raw JSON.
arg_raw() {
    echo "$_ARGS_JSON"
}