// repomapper updates and manipulate reposurfeon-style contributor maps
package main

// Copyright by Eric S. Raymond
// SPDX-License-Identifier: BSD-2-Clause

import (
	"bufio"
	"flag"
	"fmt"
	"log"
	"net/mail"
	"os"
	"regexp"
	"sort"
	"strings"
)

// Contributor - associate a username with a DVCS-style ID
type Contributor struct {
	name     string
	fullname string
	email    string
	tz       string
	definite bool
}

// Does this entry need completion?
func (cb *Contributor) incomplete() bool {
	return cb.name == cb.fullname || !strings.Contains(cb.email, "@")
}

// Stringer - render a Contributor in rereadable form
func (cb *Contributor) Stringer() string {
	out := fmt.Sprintf("%s = %s <%s>", cb.name, cb.fullname, cb.email)
	if cb.tz != "" {
		out += " " + cb.tz
	}
	out += "\n"
	return out
}

// ContribMap - a map of contributors.
type ContribMap map[string]Contributor

/* apply a specified function to each line of a file */
func bylines(fn string, hook func(string)) {
	file, err := os.Open(fn)
	if err != nil {
		log.Fatal(err)
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		hook(scanner.Text())
	}

	if err := scanner.Err(); err != nil {
		log.Fatal(err)
	}
}

// NewContribMap - initialize a new contributor map from a file */
func NewContribMap(fn string) ContribMap {
	re := regexp.MustCompile("([^ ]+) *= ([^<]+)*<([^<]+)> *(.*)")
	cm := make(map[string]Contributor)

	digest := func(line string) {
		groups := re.FindAllStringSubmatch(line, -1)
		if groups == nil {
			log.Fatal("repomapper: ill-formed map line.\n")
		}
		firstmatch := groups[0]
		v := Contributor{
			name:     firstmatch[1],
			fullname: strings.Trim(firstmatch[2], " \t"),
			email:    firstmatch[3],
			tz:       firstmatch[4],
		}
		v.definite = strings.Contains(v.email, "@")
		cm[v.name] = v
	}
	bylines(fn, digest)
	return cm
}

// Suffix - add an address suffix to entries lacking one.
func (cm *ContribMap) Suffix(addr string) {
	for k, obj := range *cm {
		if !strings.Contains(obj.email, "@") {
			obj.email += "@" + addr
			(*cm)[k] = obj
		}
	}
}

/* Write the current state of this contrib map. */
func (cm *ContribMap) Write(fp *os.File, incomplete bool) {
	keys := make([]string, 0)
	for k := range *cm {
		keys = append(keys, k)
	}
	sort.Strings(keys)
	for _, name := range keys {
		item := (*cm)[name]
		if incomplete && !item.incomplete() {
			continue
		}
		fmt.Print(item.Stringer())
	}
}

// Manifest constants describing the Unix password DSV format
const pwdFLDSEP = ":" // field separator
const pwdNAME = 0     // field index of username
const pwdGECOS = 4    // field index of fullname
const pwdFLDCOUNT = 7 // required number of fields

func main() {
	var host string
	var incomplete bool

	flag.StringVar(&host, "h", "", "set host for suffixing")
	flag.BoolVar(&incomplete, "i", false, "dump incomplete entries")
	flag.Parse()

	if flag.NArg() == 0 {
		fmt.Fprintf(os.Stderr,
			"repomapper: requires a contrib-map file argument.\n")
		os.Exit(1)
	}

	// Read in an ordered dictionary of existing attributions.
	contribmap := NewContribMap(flag.Arg(0))

	// Apply the -h option
	if host != "" {
		contribmap.Suffix(host)
	}

	for i := 1; i < flag.NArg(); i++ {
		file, err := os.Open(flag.Arg(i))
		if err != nil {
			log.Fatal(err)
		}
		defer file.Close()

		scanner := bufio.NewScanner(file)

		scanner.Scan()
		firstline := scanner.Text()
		if err := scanner.Err(); err != nil {
			log.Fatal(err)
		}

		// Is this a map file?
		if strings.Contains(firstline, "=") || firstline[0] == '#' {
			updatemap := NewContribMap(flag.Arg(i))
			for name, obj := range updatemap {
				_, ok := contribmap[name]
				if !ok {
					contribmap[name] = obj
				}
			}
			continue
		}

		// Is this a password file?
		if strings.Count(firstline, ":") > 3 {
			passwd := make(map[string]string)

			passwdline := func(line string) {
				fields := strings.Split(line, pwdFLDSEP)
				if len(fields) != pwdFLDCOUNT {
					fmt.Fprintf(os.Stderr,
						"repomapper: ill-formed passwd line\n")
					os.Exit(1)
				}
				name := fields[pwdNAME]
				gecos := fields[pwdGECOS]
				if strings.Index(gecos, ",") != 1 {
					gecos = strings.Split(gecos, ",")[0]
				}
				passwd[name] = gecos
			}

			passwdline(firstline)
			for scanner.Scan() {
				passwdline(scanner.Text())
			}
			if err := scanner.Err(); err != nil {
				log.Fatal(err)
			}

			// Attempt to fill in the contribmap
			for name, obj := range contribmap {
				_, ok := passwd[name]
				if !ok {
					fmt.Fprintf(os.Stderr,
						"repomapper: %s not in password file.\n", name)
				} else if obj.fullname == name {
					item := contribmap[name]
					item.fullname = passwd[name]
					item.definite = true
					contribmap[name] = item
				} else {
					fmt.Fprintf(os.Stderr,
						"repomapper: %s -> %s should be %s.\n",
						name, obj.fullname, passwd[name])
				}
			}
			continue
		}

		// Is this a mailbox file?
		mineAddresses := func(line string) {
			for _, fld := range strings.Split(line, ",") {
				e, err := mail.ParseAddress(fld)
				if err == nil {
					if e.Name != "" && e.Name != e.Address {
						userid := strings.Split(e.Address, "@")[0]
						if item, ok := contribmap[userid]; ok && (!strings.Contains(e.Address, "@") || !item.definite) {
							item.fullname = e.Name
							item.email = e.Address
							contribmap[userid] = item
						}
					}
				}
			}
		}
		if strings.HasPrefix(firstline, "From ") {
			for scanner.Scan() {
				line := scanner.Text()
				if strings.Contains(line, ":") {
					body := strings.Split(line, ":")[1]
					mineAddresses(body)
				} else if len(line) > 0 && (line[0] == ' ' || line[0] == '\t') {
					mineAddresses(strings.TrimSpace(line))
				}
			}

			if err := scanner.Err(); err != nil {
				log.Fatal(err)
			}
		}
	}

	// By default, report all entries
	contribmap.Write(os.Stdout, incomplete)
}

// end