main.go

package main

import (
	"path"

	_ "github.com/mattn/go-sqlite3"
	"strk.kbt.io/projects/go/libravatar"

	"bufio"
	"database/sql"
	"fmt"
	"html/template"
	"log"
	"net/http"
	"net/http/cgi"
	"net/http/fcgi"
	"net/url"
	"os"
	"os/signal"
	"strings"
	"syscall"
	"time"
)

const (
	ITEMS    = 24
	UITEMS   = 6
	DBNAME   = "llist.sqlite"
	TMPLFILE = "llist.gtml"

	CR_LINKS = `CREATE TABLE IF NOT EXISTS links (
                         id INTEGER PRIMARY KEY,
                         title TEXT, url TEXT,
                         name TEXT, posted DATETIME)`
	CR_COMM = `CREATE TABLE IF NOT EXISTS comments (
                         id INTEGER PRIMARY KEY,
                         link INTEGER NOT NULL, reply INTEGER,
                         name TEXT, content TEXT, posted DATETIME,
                         FOREIGN KEY (link) REFERENCES links (id) ON DELETE CASCADE,
                         FOREIGN KEY (reply) REFERENCES comments (id) ON DELETE CASCADE)`
	CR_TAGS = `CREATE TABLE IF NOT EXISTS tags (
                         id INTEGER PRIMARY KEY,
                         name TEXT, link INTEGER,
                         FOREIGN KEY (link) REFERENCES links (id) ON DELETE CASCADE)`
	SE_LINK = `SELECT id, title, url, posted, name,
                           (SELECT count(1) FROM comments WHERE comments.link = links.id)
                     FROM links WHERE links.id = ?`
	SE_LINKS = `SELECT id, title, url, posted, name,
                           (SELECT count(1) FROM comments WHERE comments.link = links.id)
                     FROM links
                     ORDER BY posted DESC LIMIT ? OFFSET ?`
	SE_COMM = `SELECT id, posted, name, content 
                     FROM comments
                     WHERE link = ? AND reply = ? 
                     ORDER BY posted`
	SE_BY_TAG = `SELECT links.id, title, url, posted, links.name,
                            (SELECT count(1) FROM comments WHERE comments.link = links.id)
                     FROM links
                     LEFT JOIN tags ON tags.link = links.id
                     WHERE tags.name = ?
                     ORDER BY posted DESC LIMIT ? OFFSET ?`
	SE_LINK_BY_USER = `SELECT id, title, url, posted,
                           (SELECT count(1) FROM comments WHERE comments.link = links.id)
                           FROM links
                           WHERE name = ?
                           ORDER BY posted DESC LIMIT ? OFFSET ?`
	SE_COMM_BY_USER = `SELECT id, link, content, posted
                           FROM comments
                           WHERE name = ?
                           ORDER BY posted DESC LIMIT ? OFFSET ?`
	SE_TAG_BY_OCC = `SELECT a.name FROM tags a
                         INNER JOIN tags b ON (a.name = b.name)
                         GROUP BY a.name
                         ORDER BY count(1) DESC
                         LIMIT 10;`
	SE_TAGS  = `SELECT name FROM tags WHERE link = ?`
	SE_TITLE = `SELECT title FROM links WHERE id = ?`
	IN_LINK  = `INSERT INTO links (title, url, posted, name)
                   values (?, ?, datetime("now"), ?)`
	IN_COMM = `INSERT INTO comments (link, reply, posted, name, content)
                   values (?, ?, datetime("now"), ?, ?)`
	IN_TAG  = `INSERT INTO tags (name, link) values (?, ?)`
	DE_LINK = `DELETE FROM links WHERE id = ?`
	DE_COMM = `DELETE FROM comments WHERE id = ?`
)

var (
	tmpl   *template.Template
	db     *sql.DB
	users  map[string]User
	titles map[int]string
)

type User struct {
	passwd string
	Email  string
	Descr  string
}

type Comment struct {
	Id       int
	Posted   time.Time
	Name     string
	Text     string
	Replies  []Comment
	Response int
}

type Link struct {
	Id       int
	Posted   time.Time
	Name     string
	Title    string
	Url      string
	Comments []Comment
	CCount   int
	Tags     []string
}

func init() {
	var err error
	if db, err = sql.Open("sqlite3", DBNAME); err != nil {
		log.Fatal(err)
	}

	if _, err = db.Exec(CR_LINKS); err != nil {
		log.Fatal(err)
	}
	if _, err = db.Exec(CR_TAGS); err != nil {
		log.Fatal(err)
	}
	if _, err = db.Exec(CR_COMM); err != nil {
		log.Fatal(err)
	}

	var dir = "gtml"
	if os.Getenv("GTML") != "" {
		dir = os.Getenv("GTML")
	}
	tmpl = template.Must(template.New("").Funcs(template.FuncMap{
		"inc": func(i int) int {
			return i + 1
		}, "dec": func(i int) int {
			return i - 1
		}, "domain": func(rawurl string) string {
			url, err := url.Parse(rawurl)
			if err != nil {
				return ""
			}
			return url.Host
		}, "calcStart": func(page int) int {
			return (page-1)*ITEMS + 1
		}, "isType": func(tag string) bool {
			switch tag {
			case "video", "pdf", "audio", "podcast", "slides":
				return true
			}
			return false
		}, "libr": func(author string) string {
			r, _ := libravatar.FromEmail(author)
			return r
		}, "since": func(p time.Time) string {
			d := time.Since(p)
			switch {
			case d.Hours() > 24*365:
				return fmt.Sprintf("%d years ago",
					int(d.Hours()/(24*365)))
			case d.Hours() > 24:
				return fmt.Sprintf("%d days ago",
					int(d.Hours()/24))
			case d.Hours() > 1:
				return fmt.Sprintf("%d hours ago",
					int(d.Hours()))
			case d.Minutes() > 1:
				return fmt.Sprintf("%d minutes ago",
					int(d.Minutes()))
			default: // if posted less than 1m ago
				return "just now"
			}
		}, "cGetTitle": func(id int) string {
			title, err := queryTitle(id)
			if err != nil {
				return "N/A"
			}
			return title
		},
	}).ParseGlob(dir + "/*.gtml"))
}

func forceLoadUsers() {
	users = make(map[string]User)
	var userf string
	if userf = os.Getenv("USERF"); userf == "" {
		userf = "/etc/llist_users"
	}

	unf, err := os.Open(userf)
	defer unf.Close()
	if err != nil && !os.IsNotExist(err) {
		log.Fatal(err)
	}
	sca := bufio.NewScanner(unf)
	if sca.Err() != nil {
		log.Fatal(sca.Err())
	}
	lc := 1          // line counter
	for sca.Scan() { // name:email:passwd
		line := sca.Text()
		if len(strings.TrimSpace(line)) == 0 {
			lc++
			continue // ignore empty lines
		}
		parts := strings.SplitN(line, ":", 4)
		if len(parts) < 4 {
			log.Printf("Malformed line %d to be ignored: %s\n", lc, line)
			continue
		}
		users[parts[0]] = User{
			passwd: parts[1],
			Email:  parts[2],
			Descr:  parts[3],
		}
		lc++
	}
}

func loadUsers() {
	if len(users) == 0 { // find better/more efficient solution
		forceLoadUsers()
	}
}

func main() {
	defer db.Close()

	// reaload users when SIGUSER1 is caught
	c := make(chan os.Signal)
	signal.Notify(c, syscall.SIGUSR1)
	go func() {
		for {
			_ = <-c
			forceLoadUsers()
		}
	}()

	http.HandleFunc("/subm", submit)
	http.HandleFunc("/user", genuser)
	http.HandleFunc("/post", genpost)
	http.HandleFunc("/delete", delete)
	http.HandleFunc("/rss", genrss)
	http.HandleFunc("/", genlist)

	mux := http.NewServeMux()
	mux.HandleFunc("/", func(rw http.ResponseWriter, req *http.Request) {
		rw.Header().Set("Content-Type", "text/html")
		path := path.Dir(req.URL.Path)
		if path == "" || path == "/" {
			genlist(rw, req)
			return
		}
		http.StripPrefix(path, http.DefaultServeMux).ServeHTTP(rw, req)
	})

	if strings.HasSuffix(os.Args[0], ".cgi") {
		log.Println(cgi.Serve(mux))
	} else if strings.HasSuffix(os.Args[0], ".fcgi") {
		log.Println(fcgi.Serve(nil, mux))
	} else {
		if port := os.Getenv("PORT"); port == "" {
			log.Fatal("$PORT not defined")
		} else {
			log.Fatal(http.ListenAndServe(":"+port, nil))
		}
	}
}