package main

import (
	"database/sql"
	"encoding/json"
	"flag"
	"fmt"
	"math/rand"
	"net/http"
	"os"
	"path"
	"time"

	"github.com/speps/go-hashids"

	_ "github.com/mattn/go-sqlite3"

	"github.com/gorilla/mux"
	"github.com/jmoiron/sqlx"
	"github.com/rs/zerolog"
	"github.com/rs/zerolog/log"
	"github.com/stretchr/graceful"
)

var (
	distPath   = flag.String("dist", "frontend/dist", "path to dist files")
	salt       = flag.String("salt", "happy", "salt for IDs")
	minHashLen = flag.Int("minHashLen", 4, "minimum ID hash size")
	develop    = flag.Bool("develop", false, "turn on develop mode")
)

func main() {
	flag.Parse()
	log.Logger = log.Logger.Output(zerolog.ConsoleWriter{Out: os.Stderr})
	zerolog.SetGlobalLevel(zerolog.DebugLevel)
	s := server{
		addr:      "0.0.0.0:8080",
		assetPath: "pub",
		salt:      *salt,
	}
	db, err := sqlx.Connect("sqlite3", "happy.db")
	if err != nil {
		log.Fatal().
			Err(err).
			Msg("could not connect to database")
	}
	s.db = db
	hd := hashids.NewData()
	hd.Salt = s.salt
	hd.MinLength = *minHashLen
	s.h, _ = hashids.NewWithData(hd)
	if err := s.makeDB(); err != nil {
		log.Fatal().
			Err(err).
			Msg("could not create database")
	}
	s.serve()
}

type server struct {
	addr      string
	assetPath string
	db        *sqlx.DB
	salt      string
	h         *hashids.HashID
}

func (s *server) makeDB() error {
	q := `create table if not exists users (
		id integer primary key,
		email text unique,
		verification integer not null,
		dateCreated integer,
		lastLogin integer
	)`
	if _, err := s.db.Exec(q); err != nil {
		return err
	}
	q = `create table if not exists mood_categories (
		id integer primary key,
		name text
	)`
	if _, err := s.db.Exec(q); err != nil {
		return err
	}
	q = `create table if not exists mood_category_texts (
		id integer primary key,
		mood_category_id integer,
		key text,
		value integer,
		foreign key(mood_category_id) references mood_categories(id)

	)`
	if _, err := s.db.Exec(q); err != nil {
		return err
	}
	q = `create table if not exists moods (
		id integer primary key,
		user_id integer,
		mood_category_id integer,
		value integer,
		time integer,
		foreign key(user_id) references users(id),
		foreign key(mood_category_id) references mood_categories(id)
	)`
	if _, err := s.db.Exec(q); err != nil {
		return err
	}
	return nil
}

func (s *server) recordMood(mood getMoodsResponse, who UserID) error {
	q := `insert into moods (user_id,mood_category_id,value,time) values (?,?,?,?)`
	_, err := s.db.Exec(q, who.ID, mood.CategoryID, mood.Value, time.Now().Unix())
	return err
}

type UserID struct {
	db *sqlx.DB

	ID           int64
	Email        sql.NullString
	Verification int64
	DateCreated  sql.NullInt64 `db:"dateCreated"`
	LastLogin    sql.NullInt64 `db:"lastLogin"`

	salt int64
	str  string
}

func (s *server) NewUserID() (UserID, error) {
	uid := UserID{
		db:           s.db,
		DateCreated:  sql.NullInt64{time.Now().Unix(), true},
		LastLogin:    sql.NullInt64{time.Now().Unix(), true},
		Verification: rand.Int63(),
	}
	q := `insert into users (verification,dateCreated) values (?, ?)`
	res, err := s.db.Exec(q, uid.Verification, uid.DateCreated)
	if err != nil {
		return uid, err
	}
	id, err := res.LastInsertId()
	if err != nil {
		return uid, err
	}
	uid.ID = id
	idstr, err := s.h.EncodeInt64([]int64{id})
	if err != nil {
		return uid, err
	}
	uid.str = idstr
	return uid, nil
}

func (s *server) FromStr(uid, verification string) (UserID, error) {
	id := UserID{db: s.db}
	idInt, err := s.h.DecodeInt64WithError(uid)
	if err != nil {
		return id, err
	}
	q := `select id,email,verification,datecreated,lastlogin from users where id=?`
	if err := s.db.Get(&id, q, idInt[0]); err != nil {
		log.Error().
			Err(err).
			Msg("unable to select")
		return id, err
	}
	verify, err := s.h.EncodeInt64([]int64{id.Verification})
	if err != nil {
		log.Error().
			Err(err).
			Str("verify", verify).
			Str("id.Verification", verification).
			Msg("unable to encode")
		return id, err
	}
	if verify != verification {
		log.Debug().
			Str("verify", verify).
			Str("id.Verification", verification).
			Msg("verification mismatch")
		return id, fmt.Errorf("Invalid verification token")
	}
	return id, nil
}

func (u UserID) String() string {
	return u.str
}

type RegisterResponse struct {
	ID          string
	DateCreated int64
	Validation  string `json:",omitempty"`
}

func (s *server) handlerRegisterCode(w http.ResponseWriter, r *http.Request) {
	uid, err := s.NewUserID()
	if err != nil {
		w.WriteHeader(500)
		log.Error().Err(err).Msg("error from NewUserID")
		fmt.Fprintf(w, "Error registering user: %s", err)
		return
	}
	if err != nil {
		w.WriteHeader(500)
		log.Error().Err(err).Msg("error converting date")
		fmt.Fprintf(w, "Error registering user: %s", err)
		return
	}
	resp := RegisterResponse{
		ID:          uid.String(),
		DateCreated: uid.DateCreated.Int64,
	}
	if *develop {
		resp.Validation, _ = s.h.EncodeInt64([]int64{uid.Verification})
	}
	out, err := json.Marshal(resp)
	if err != nil {
		w.WriteHeader(500)
		log.Error().Err(err).Msg("error from json.Marshal")
		fmt.Fprintf(w, "Error registering user: %s", err)
		return
	}
	fmt.Fprintf(w, "%s", string(out))
}

type getMoodsResponse struct {
	CategoryID   int64  `db:"category_id"`
	CategoryName string `db:"category_name"`
	Key          string
	Value        int64
}

func (s *server) getMoods(w http.ResponseWriter, r *http.Request) {
	log.Debug().Interface("req", r).Msg("getMoods")
	q := `select mc.id category_id,mc.name category_name,mct.key,mct.value
		from mood_categories mc 
		    inner join mood_category_texts mct 
		        on mc.id=mct.mood_category_id`
	recs := []getMoodsResponse{}
	err := s.db.Select(&recs, q)
	if err != nil {
		log.Error().Err(err).Msg("could not retrieve mood categories and texts")
		w.WriteHeader(500)
		fmt.Fprintf(w, "Error getting moods: %s", err)
		return
	}
	resp, err := json.Marshal(recs)
	if err != nil {
		log.Error().Err(err).Msg("error from json.Marshal")
		w.WriteHeader(500)
		fmt.Fprintf(w, "Error getting moods: %s", err)
		return
	}
	fmt.Fprintf(w, "%s", string(resp))
}

func (s *server) handleMood(w http.ResponseWriter, r *http.Request) {
	uid := r.Header.Get("X-user-id")
	verify := r.Header.Get("X-user-validation")
	log.Debug().
		Str("uid", uid).
		Str("verify", verify).
		Msg("handleMood")
	dec := json.NewDecoder(r.Body)
	happyReq := getMoodsResponse{}
	err := dec.Decode(&happyReq)
	if err != nil {
		log.Error().Err(err).Msg("error with happy")
		w.WriteHeader(400)
		fmt.Fprintf(w, err.Error())
		return
	}
	log.Debug().
		Interface("mood", happyReq).
		Msg("mood")
	user, err := s.FromStr(uid, verify)
	if err != nil {
		log.Error().
			Err(err).
			Msg("error getting user")
		w.WriteHeader(403)
		fmt.Fprintf(w, "Error: %s", err)
		return
	}
	if err := s.recordMood(happyReq, user); err != nil {
		log.Error().Err(err).Msg("error saving mood")
		w.WriteHeader(500)
		fmt.Fprintf(w, "Error: %s", err)
		return
	}
	fmt.Fprintf(w, "ok")
}

func (s *server) indexHandler(entryPoint string) func(w http.ResponseWriter, r *http.Request) {
	fn := func(w http.ResponseWriter, r *http.Request) {
		p := path.Join(*distPath, path.Clean(r.URL.Path))
		f, err := os.Stat(p)
		if !os.IsNotExist(err) && !f.IsDir() {
			http.ServeFile(w, r, p)
			return
		}
		p = path.Join(p, "index.html")
		if f, err := os.Stat(p); !os.IsNotExist(err) && !f.IsDir() {
			http.ServeFile(w, r, p)
			return
		}
		http.ServeFile(w, r, path.Join(*distPath, entryPoint))
	}
	return fn
}

func (s *server) routeSetup() *mux.Router {
	r := mux.NewRouter()
	api := r.PathPrefix("/v1/").Subrouter()
	api.HandleFunc("/moods", s.getMoods).Methods("GET")
	api.HandleFunc("/moods", s.handleMood).Methods("POST")
	api.HandleFunc("/register/code", s.handlerRegisterCode).Methods("GET")
	r.PathPrefix("/").HandlerFunc(s.indexHandler("/index.html"))
	return r
}

func (s *server) serve() {
	middle := s.routeSetup()
	log.Info().Str("addr", "http://"+s.addr).Msg("serving HTTP")
	graceful.Run(s.addr, 10*time.Second, middle)
}