//! Output formatting: the ✦ / ✗ habit, colour that can be turned off, and the
//! `--json` shapes agents read.
//!
//! Every command that prints data has a JSON form with stable field names, and
//! every error is `{"error": "..."}` on stderr. Exit codes are fixed: 0
//! success, 1 refusal or error, 2 bad usage.

module cli

import json
import os

const glyph_ok = '✦'
const glyph_fail = '✗'

pub fn color_enabled() bool {
	if os.getenv('NO_COLOR') != '' || os.getenv('KOH_NO_COLOR') != '' {
		return false
	}
	return os.is_atty(1) != 0
}

fn paint(text string, code string) string {
	if !color_enabled() {
		return text
	}
	return '\x1b[${code}m${text}\x1b[0m'
}

pub fn amber(text string) string {
	return paint(text, '38;5;214')
}

pub fn red(text string) string {
	return paint(text, '38;5;203')
}

pub fn dim(text string) string {
	return paint(text, '38;5;245')
}

pub fn green(text string) string {
	return paint(text, '38;5;114')
}

pub fn ok(message string) {
	println('  ${amber(glyph_ok)} ${message}')
}

pub fn note(message string) {
	println('  ${dim(message)}')
}

pub fn warn(message string) {
	println('  ${amber('!')} ${message}')
}

// fail prints a refusal and returns the exit code to hand back.
pub fn fail(message string) int {
	eprintln('  ${red(glyph_fail)} ${message}')
	return 1
}

pub fn fail_json(message string) int {
	eprintln(json.encode({
		'error': message
	}))
	return 1
}

pub fn usage_error(message string) int {
	eprintln('  ${red(glyph_fail)} ${message}')
	return 2
}

// refuse reports an error in whichever shape the command was asked for.
pub fn refuse(as_json bool, message string) int {
	if as_json {
		return fail_json(message)
	}
	return fail(message)
}

pub fn emit_json(value string) {
	println(value)
}