package main

import (
	"embed"
	"encoding/json"
	"errors"
	"fmt"
	"html/template"
	"net/http"
	"net/url"
	"strings"
	"time"

	"git.milar.in/milarin/advsql"
	"git.milar.in/milarin/channel"
	"git.milar.in/milarin/envvars/v2"
	"github.com/gorilla/mux"
)

var (
	//go:embed templates/*
	TemplateFS embed.FS

	//go:embed static/*
	StaticFS embed.FS

	Templates *template.Template
)

func main() {
	advsql.InitMysqlDatabase(
		Database,
		envvars.String("DB_HOST", ""),
		envvars.Uint16("DB_PORT", 3306),
		envvars.String("DB_USER", ""),
		envvars.String("DB_PASS", ""),
		envvars.String("DB_BASE", "startpage"),
	)
	defer Database.Close()

	if tmpl, err := template.New("homepage").Funcs(tmplFuncs).ParseFS(TemplateFS, "templates/*"); err == nil {
		Templates = tmpl
	} else {
		panic(err)
	}

	r := mux.NewRouter()
	r.HandleFunc("/", handler)
	r.HandleFunc("/customize", customize)
	r.HandleFunc("/save-changes", saveChanges)
	r.HandleFunc("/search", search)
	r.PathPrefix("/static/").Handler(http.FileServer(http.FS(StaticFS)))

	go func() {
		for range time.Tick(time.Hour) {
			if err := DeleteSessionsByExpirationDateBefore(time.Now()); err != nil {
				fmt.Println("could not delete expired sessions", err)
			}
		}
	}()

	if err := http.ListenAndServe(fmt.Sprintf("%s:%d", envvars.String("HTTP_INTF", ""), envvars.Uint16("HTTP_PORT", 80)), r); err != nil {
		panic(err)
	}
}

func handler(w http.ResponseWriter, r *http.Request) {
	session, err := GetSession(w, r)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Println(err)
		return
	}

	data := &TmplData{
		text:      GetText(r),
		Bookmarks: channel.ToSliceDeref(GetBookmarksBySessionIdOrdered(session.ID)),
		Settings:  GetSettingsBySessionID(session.ID),
	}

	if err := Templates.ExecuteTemplate(w, "index.html", data); err != nil {
		panic(err)
	}
}

func search(w http.ResponseWriter, r *http.Request) {
	session, err := GetSession(w, r)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Println(err)
		return
	}
	settings := GetSettingsBySessionID(session.ID)

	if err := r.ParseForm(); err != nil {
		fmt.Println(err)
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	query := r.Form.Get("query")

	if uri, err := ParseURI(query); err == nil {
		// url
		w.Header().Add("Location", uri.String())
		w.WriteHeader(http.StatusMovedPermanently)
	} else {
		// search string
		w.Header().Add("Location", fmt.Sprintf(settings.Search, query))
		w.WriteHeader(http.StatusMovedPermanently)
	}

}

func customize(w http.ResponseWriter, r *http.Request) {
	session, err := GetSession(w, r)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Println(err)
		return
	}

	text := GetText(r)

	data := &CustomizeData{
		text:     text,
		Settings: GetSettingsBySessionID(session.ID),
		Bookmarks: channel.ToSliceDeref(channel.MapSuccessive(GetBookmarksBySessionIdOrdered(session.ID), func(b *Bookmark) *BookmarkData {
			return &BookmarkData{
				Bookmark: b,
				text:     text,
			}
		})),
	}

	if err := Templates.ExecuteTemplate(w, "customize.html", data); err != nil {
		panic(err)
	}
}

func saveChanges(w http.ResponseWriter, r *http.Request) {
	if r.Method != "POST" {
		w.WriteHeader(http.StatusMethodNotAllowed)
		return
	}

	session, err := GetSession(w, r)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Println(err)
		return
	}

	sessionData := &SessionData{}
	err = json.NewDecoder(r.Body).Decode(&sessionData)
	if err != nil {
		fmt.Println(err)
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	for _, bookmark := range sessionData.Bookmarks {
		uri, err := url.Parse(bookmark.Link)
		if err != nil {
			fmt.Println(err)
			w.WriteHeader(http.StatusBadRequest)
			return
		}
		if uri.Scheme == "" {
			uri.Scheme = "https"
		}
		bookmark.Link = uri.String()
	}

	Reorder(sessionData.Bookmarks)
	if err := DeleteBookmarksBySessionID(session.ID); err != nil {
		fmt.Println(err)
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	for _, bookmark := range sessionData.Bookmarks {
		bookmark.SessionID = session.ID
		if err := InsertBookmark(&bookmark); err != nil {
			fmt.Println(err)
			w.WriteHeader(http.StatusInternalServerError)
			return
		}
	}

	sessionData.Settings.SessionID = session.ID
	if err := UpdateSettings(sessionData.Settings); err != nil {
		fmt.Println(err)
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
}

func ParseURI(uri string) (*url.URL, error) {
	if !strings.HasPrefix(uri, "http://") && !strings.HasPrefix(uri, "https://") {
		uri = "https://" + uri
	}

	ret, err := url.ParseRequestURI(uri)
	if err != nil {
		return nil, err
	}

	splits := strings.Split(ret.Hostname(), ".")
	if len(splits) <= 1 {
		return nil, errors.New("hostname doesn't have a TLD")
	}

	if _, ok := TLDs[splits[len(splits)-1]]; !ok {
		return nil, errors.New("invalid top level domain")
	}

	return ret, nil
}