// Package parse provides utility functions for parsing and reading data from files.
package parse

import (
	"bufio"
	"log"
	"os"
	"strconv"
	"strings"

	"golang.org/x/exp/constraints"
)

// ReadLines reads all lines from a file specified by fileName and returns them as a slice of strings.
func ReadLines(fileName string) []string {
	result := []string{}
	file, err := os.Open(fileName)
	if err != nil {
		log.Fatal(err)
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		result = append(result, scanner.Text())
	}

	if err := scanner.Err(); err != nil {
		log.Fatal(err)
	}

	return result
}

// ParseIntArray parses a string containing integer values separated by a specified separator and returns a slice of integers.
func ParseIntArray[T constraints.Integer](s string, sep string) []T {
	result := []T{}

	var vals []string
	if sep == " " {
		vals = strings.Fields(strings.TrimSpace(s))
	} else {
		vals = strings.Split(strings.TrimSpace(s), sep)
	}

	for _, val := range vals {
		n, e := strconv.ParseInt(strings.TrimSpace(val), 10, 64)
		if e != nil {
			log.Fatal(e)
		}

		result = append(result, T(n))
	}

	return result
}

// SplitNoBlank splits a string by a specified separator and returns a slice of the non-empty parts.
func SplitNoBlank(s string, sep string) []string {
	splitted_line := strings.Split(s, sep)

	result := []string{}

	for _, part := range splitted_line {
		if part != "" {
			result = append(result, part)
		}
	}

	return result
}