// Copyright (c) 2019-2023 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
import os

fn main() {
    mut path := 'cinderella.txt'
    if os.args.len != 2 {
        println('usage: word_counter [text_file]')
        println('using ${path}')
    } else {
        path = os.args[1]
    }
    contents := os.read_file(path.trim_space()) or {
        println('failed to open ${path}')
        return
    }
    mut m := map[string]int{}
    for word in extract_words(contents) {
        m[word]++
    }
    // Sort the keys
    mut keys := m.keys()
    keys.sort()
    // Print the map
    for key in keys {
        val := m[key]
        println('${key} => ${val}')
    }
}

// Creates an array of words from a given string
fn extract_words(contents string) []string {
    mut splits := []string{}
    for space_split in contents.to_lower().split(' ') {
        if space_split.contains('\n') {
            splits << space_split.split('\n')
        } else {
            splits << space_split
        }
    }

    mut results := []string{}
    for s in splits {
        result := filter_word(s)
        if result == '' {
            continue
        }
        results << result
    }

    return results
}

// Removes punctuation
fn filter_word(word string) string {
    if word == '' || word == ' ' {
        return ''
    }
    mut i := 0
    for i < word.len && !word[i].is_letter() {
        i++
    }
    start := i
    for i < word.len && word[i].is_letter() {
        i++
    }
    end := i
    return word[start..end]
}