package pkg

import (
	"bufio"
	"errors"
	"fmt"
	"os"
	"strings"
)

var (
	errInvalidNumberOfElements = errors.New("more than two space-separated 2 elements on the line")
	errEmptyLine               = errors.New("empty line")
)

type parsedLine struct {
	rawurl string
	branch string
}

// ParseDumpFile opens a given gitgetfile and parses its content into a slice of CloneOpts.
func parseDumpFile(path string) ([]parsedLine, error) {
	file, err := os.Open(path)
	if err != nil {
		return nil, fmt.Errorf("failed opening dump file %s: %w", path, err)
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)

	var (
		parsedLines []parsedLine
		line        int
	)

	for scanner.Scan() {
		line++

		parsed, err := parseLine(scanner.Text())
		if err != nil && !errors.Is(errEmptyLine, err) {
			return nil, fmt.Errorf("failed parsing dump file line %d: %w", line, err)
		}

		parsedLines = append(parsedLines, parsed)
	}

	return parsedLines, nil
}

// parseLine splits a dump file line into space-separated segments.
// First part is the URL to clone. Second, optional, is the branch (or tag) to checkout after cloning
func parseLine(line string) (parsedLine, error) {
	var parsed parsedLine

	if len(strings.TrimSpace(line)) == 0 {
		return parsed, errEmptyLine
	}

	parts := strings.Split(strings.TrimSpace(line), " ")
	if len(parts) > 2 {
		return parsed, errInvalidNumberOfElements
	}

	parsed.rawurl = parts[0]
	if len(parts) == 2 {
		parsed.branch = parts[1]
	}

	return parsed, nil
}