// Copyright 2013 The Go Authors. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd.

package gosrc

import (
	"regexp"
	"strconv"
	"strings"
)

var defaultTags = map[string]string{"git": "master", "hg": "default"}

func bestTag(tags map[string]string, defaultTag string) (string, string, error) {
	if commit, ok := tags["go1"]; ok {
		return "go1", commit, nil
	}
	if commit, ok := tags[defaultTag]; ok {
		return defaultTag, commit, nil
	}
	return "", "", NotFoundError{Message: "Tag or branch not found."}
}

// expand replaces {k} in template with match[k] or subs[atoi(k)] if k is not in match.
func expand(template string, match map[string]string, subs ...string) string {
	var p []byte
	var i int
	for {
		i = strings.Index(template, "{")
		if i < 0 {
			break
		}
		p = append(p, template[:i]...)
		template = template[i+1:]
		i = strings.Index(template, "}")
		if s, ok := match[template[:i]]; ok {
			p = append(p, s...)
		} else {
			j, _ := strconv.Atoi(template[:i])
			p = append(p, subs[j]...)
		}
		template = template[i+1:]
	}
	p = append(p, template...)
	return string(p)
}

var readmePat = regexp.MustCompile(`(?i)^readme(?:$|\.)`)

// isDocFile returns true if a file with name n should be included in the
// documentation.
func isDocFile(n string) bool {
	if strings.HasSuffix(n, ".go") && n[0] != '_' && n[0] != '.' {
		return true
	}
	return readmePat.MatchString(n)
}

var linePat = regexp.MustCompile(`(?m)^//line .*$`)

func OverwriteLineComments(p []byte) {
	for _, m := range linePat.FindAllIndex(p, -1) {
		for i := m[0] + 2; i < m[1]; i++ {
			p[i] = ' '
		}
	}
}