// netrc -- parse .netrc file
// Copyright 2018 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.

// netrc library parses .netrc file. It is copy-paste of
// golang.org/x/tools/cmd/auth/netrcauth.
//
// See https://www.gnu.org/software/inetutils/manual/html_node/The-_002enetrc-file.html
// for documentation on the .netrc format.
package netrc

import (
	"os"
	"path"
	"strings"
)

type Line struct {
	Machine  string
	Login    string
	Password string
}

func Parse(data string) []Line {
	var nrc []Line
	var l Line
	inMacro := false
	for _, line := range strings.Split(data, "\n") {
		if inMacro {
			if line == "" {
				inMacro = false
			}
			continue
		}
		f := strings.Fields(line)
		i := 0
		for ; i < len(f)-1; i += 2 {
			// Reset at each "machine" token.
			// "The auto-login process searches the .netrc file for a machine token
			// that matches […]. Once a match is made, the subsequent .netrc tokens
			// are processed, stopping when the end of file is reached or another
			// machine or a default token is encountered."
			switch f[i] {
			case "machine":
				l = Line{Machine: f[i+1]}
			case "default":
				break
			case "login":
				l.Login = f[i+1]
			case "password":
				l.Password = f[i+1]
			case "macdef":
				// "A macro is defined with the specified name; its contents begin with
				// the next .netrc line and continue until a null line (consecutive
				// new-line characters) is encountered."
				inMacro = true
			}
			if l.Machine != "" && l.Login != "" && l.Password != "" {
				nrc = append(nrc, l)
				l = Line{}
			}
		}
		if i < len(f) && f[i] == "default" {
			// "There can be only one default token, and it must be after all machine tokens."
			break
		}
	}
	return nrc
}

func Path() (netrc string) {
	p, ok := os.LookupEnv("NETRC")
	if ok {
		return p
	}
	homeDir, _ := os.UserHomeDir()
	return path.Join(homeDir, ".netrc")
}

func Find(host string) (login string, password string) {
	data, err := os.ReadFile(Path())
	if err != nil {
		return "", ""
	}
	for _, l := range Parse(string(data)) {
		if l.Machine == host {
			return l.Login, l.Password
		}
	}
	return "", ""
}