package main

import (
	"errors"
	"io"
	"text/scanner"
)

type Submodule struct {
	Name string
	Path string
}

var SyntaxError error = errors.New("Syntax error")

func (sub *Submodule) parseSubmoduleName(s *scanner.Scanner) error {
	s.Scan()
	if s.TokenText() != "submodule" {
		return SyntaxError
	}
	s.Scan()
	sub.Name = s.TokenText()
	l := len(sub.Name)
	if sub.Name[0] != '"' || sub.Name[l-1] != '"' || s.ErrorCount > 0 {
		return SyntaxError
	}
	sub.Name = sub.Name[1 : len(sub.Name)-1]
	s.Scan()
	if s.TokenText() != "]" {
		return SyntaxError
	}
	return nil
}

func ParseSubmodulesFile(reader io.Reader) ([]Submodule, error) {
	ret := make([]Submodule, 0, 100)

	s := new(scanner.Scanner)
	s.Init(reader)

	sub := &Submodule{}
	for tok := s.Scan(); tok != scanner.EOF; tok = s.Scan() {
		t := s.TokenText()

		if t == "[" {
			if err := sub.parseSubmoduleName(s); err != nil {
				return nil, err
			}
		}
		ret = append(ret, *sub)
	}
	return ret, nil
}