// Copyright (c) 2021 Lars Pontoppidan. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module input

import os

// Config is used to configure input to the toml module.
// Only one of the fields `text` and `file_path` is allowed to be set at time of configuration.
pub struct Config {
pub:
    text      string // TOML text
    file_path string // '/path/to/file.toml'
}

// read_input returns either Config.text or the read file contents of Config.file_path
// depending on which one is not empty.
pub fn (c Config) read_input() !string {
    if c.file_path != '' && c.text != '' {
        return error(@MOD + '.' + @FN +
            ' ${typeof(c).name} should contain only one of the fields `file_path` OR `text` filled out')
    }
    if c.file_path == '' && c.text == '' {
        // TODO: passing both empty is used *a lot* by `./v vlib/toml/tests/toml_lang_test.v`; investigate why.
        return ''
    }
    if c.text != '' {
        return c.text
    }
    text := os.read_file(c.file_path) or {
        return error(@MOD + '.' + @STRUCT + '.' + @FN +
            ' Could not read "${c.file_path}": "${err.msg()}"')
    }
    return text
}