use fmt;
use io;
use locale;
use strings;

// A line in the file, which can be a comment (or a blank line), an entry, or
// a localized entry.
export type line = (blank | comment | group_header | entry);

// A blank line.
// Specification: §3.1
export type blank = void;

// A comment.
// Specification: §3.1
export type comment = str;

// A group header.
// Specification: §3.2
export type group_header = str;

// An entry in a desktop file. Entries without an explicitly stated locale are
// assigned [[locale::c]].
// Specification: §3.3, §5
export type entry = struct {
	group:  str,
	key:    str,
	value:  str,
	locale: locale::locale,
};

// Duplicates an [[entry]]. Use [[entry_finish]] to get rid of it.
export fn entry_dup(entr: entry) entry = entry {
	group  = strings::dup(entr.group),
	key    = strings::dup(entr.key),
	value  = strings::dup(entr.value),
	locale = locale::dup(entr.locale),
};

// Frees memory associated with an [[entry]].
export fn entry_finish(entr: entry) void = {
	free(entr.group);
	free(entr.key);
	free(entr.value);
	locale::finish(entr.locale);
};

// Formats a [[line]] and writes it to an [[io::handle]].
export fn fprint(output: io::handle, lin: line) (size | io::error) = match (lin) {
case blank                 => yield fmt::fprintln(output);
case let lin: comment      => yield fmt::fprintf(output, "#{}\n", lin: str);
case let lin: group_header => yield fmt::fprintf(output, "[{}]\n", lin: str);
case let lin: entry =>
	let wrote = fmt::print(lin.key)?;
	if (!locale::equal(locale::c, lin.locale)) {
		let localestr = locale::format(lin.locale);
		defer free(localestr);
		wrote += fmt::printf("[{}]", localestr)?;
	};
	wrote += fmt::printf("={}\n", lin.value)?;
	yield wrote;
};