const std = @import("std");

const Allocator = std.mem.Allocator;
const ArrayList = std.ArrayList;
const StringBuilder = @This();

pub const Error = std.mem.Allocator.Error;
pub const Writer = std.io.Writer(*StringBuilder, Error, writeFn);

data: ArrayList(u8),

pub fn init(allocator: std.mem.Allocator) StringBuilder {
    return .{
        .data = ArrayList(u8).init(allocator),
    };
}

pub fn deinit(self: StringBuilder) void {
    self.data.deinit();
}

pub fn append(self: *StringBuilder, char: u8) Error!void {
    return self.data.append(char);
}

pub fn appendMany(self: *StringBuilder, chars: []const u8) Error!void {
    return self.data.appendSlice(chars);
}

pub fn seeSlice(self: *StringBuilder) []const u8 {
    return self.data.items;
}

pub fn toOwnedSlice(self: StringBuilder) []u8 {
    return self.data.toOwnedSlice();
}

pub fn writer(self: *StringBuilder) Writer {
    return Writer{ .context = self };
}

fn writeFn(self: *StringBuilder, chars: []const u8) Error!usize {
    try self.appendMany(chars);
    return chars.len;
}