// Copyright 2018 Frank Schroeder. All rights reserved.

// Use of this source code is governed by a BSD-style

// license that can be found in the LICENSE file.

package properties

import (

	"fmt"

	"runtime"

)

type parser struct {

	lex *lexer

}

func parse(input string) (properties *Properties, err error) {

	p := &parser{lex: lex(input)}

	defer p.recover(&err)

	properties = NewProperties()

	key := ""

	comments := []string{}

	for {

		token := p.expectOneOf(itemComment, itemKey, itemEOF)

		switch token.typ {

		case itemEOF:

			goto done

		case itemComment:

			comments = append(comments, token.val)

			continue

		case itemKey:

			key = token.val

			if _, ok := properties.m[key]; !ok {

				properties.k = append(properties.k, key)

			}

		}

		token = p.expectOneOf(itemValue, itemEOF)

		if len(comments) > 0 {

			properties.c[key] = comments

			comments = []string{}

		}

		switch token.typ {

		case itemEOF:

			properties.m[key] = ""

			goto done

		case itemValue:

			properties.m[key] = token.val

		}

	}

done:

	return properties, nil

}

func (p *parser) errorf(format string, args ...interface{}) {

	format = fmt.Sprintf("properties: Line %d: %s", p.lex.lineNumber(), format)

	panic(fmt.Errorf(format, args...))

}

func (p *parser) expectOneOf(expected ...itemType) (token item) {

	token = p.lex.nextItem()

	for _, v := range expected {

		if token.typ == v {

			return token

		}

	}

	p.unexpected(token)

	panic("unexpected token")

}

func (p *parser) unexpected(token item) {

	p.errorf(token.String())

}

// recover is the handler that turns panics into returns from the top level of Parse.

func (p *parser) recover(errp *error) {

	e := recover()

	if e != nil {

		if _, ok := e.(runtime.Error); ok {

			panic(e)

		}

		*errp = e.(error)

	}

}