--[[
  [[ User program to compute SHA-256 hashes of files for Halude
  [[ Copyright (C) 2026  tema5002
  [[
  [[ This program is free software; you can redistribute it and/or
  [[ modify it under the terms of the GNU General Public License
  [[ as published by the Free Software Foundation; either version 2
  [[ of the License, or (at your option) any later version.
  [[
  [[ This program is distributed in the hope that it will be useful,
  [[ but WITHOUT ANY WARRANTY; without even the implied warranty of
  [[ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  [[ GNU General Public License for more details.
  [[
  [[ You should have received a copy of the GNU General Public License
  [[ along with this program; If not, see <http://www.gnu.org/licenses/>.
  ]]--

local fs = require("filesystem")
local shell = require("shell")

local args = {...}

if not files[1] then
    return shell.run("help sha256sum")
end

local sha256 = require("sha256")

for _, file in ipairs(args) do
    file = shell.resolvePath(file)

    local handle = fs.open(file, "r")
    if not handle then
        print("\27[91msha256sum: can't open " .. file .. ".\27[0m")
        goto continue
    end

    local ctx = sha256.init()
    while true do
        local chunk = handle:read(256)
        if not chunk then break end
        sha256.update(ctx, chunk)
    end
    handle:close()
    local hash_bytes = sha256.final(ctx)
    termlib.write(sha256.to_hex(hash_bytes) .. "  " ..file.. "\n")
    ::continue::
end