package switchcounter

import (
	"context"
	"encoding/json"
	"io/ioutil"
	"net/http"
	"path"
	"strconv"
	"time"

	"github.com/celrenheit/sandflake"
	r "gopkg.in/rethinkdb/rethinkdb-go.v6"
	"within.website/ln"
)

func (s *Switches) ByID(ctx context.Context, id string) (*Switch, error) {
	var result Switch
	res, err := r.Table("switches").
		Get(id).
		Run(s.session)
	if err != nil {
		return nil, err
	}

	err = res.One(&result)
	if err != nil {
		return nil, err
	}

	return &result, nil
}

func (s *Switches) Get(ctx context.Context, limit, page int) ([]Switch, error) {
	var result []Switch
	res, err := r.Table("switches").
		OrderBy(r.Desc("started_at")).
		Skip(page * limit).
		Limit(limit).
		Run(s.session)
	if err != nil {
		return nil, err
	}

	err = res.All(&result)
	if err != nil {
		return nil, err
	}

	return result, nil
}

func (s *Switches) Switch(ctx context.Context, who string) (Switch, Switch, error) {
	var lastSw Switch
	var currentSw Switch

	ln.Log(ctx, ln.Info("getting last switch"))
	res, err := r.Table("switches").
		OrderBy(r.Desc("started_at")).
		Limit(1).
		Run(s.session)
	if err != nil {
		return lastSw, currentSw, err
	}

	err = res.One(&lastSw)
	if err != nil {
		return lastSw, currentSw, err
	}

	f := ln.F{
		"from": lastSw.Who,
		"to":   who,
	}
	ln.Log(ctx, f, ln.Info("got last switch"))

	now := time.Now().UTC()
	lastSw.EndedAt = &now
	lastSw.Duration = now.Sub(lastSw.StartedAt).Round(time.Second)
	err = r.Table("switches").
		Update(lastSw).
		Exec(s.session)
	if err != nil {
		return lastSw, currentSw, err
	}

	currentSw = Switch{
		ID:        sandflake.Next().String(),
		Who:       who,
		StartedAt: now,
	}

	err = r.Table("switches").
		Insert(currentSw).
		Exec(s.session)
	if err != nil {
		return lastSw, currentSw, err
	}

	ln.Log(ctx, f, ln.Info("switched"))

	return lastSw, currentSw, nil
}

func (s *Switches) GetID(rw http.ResponseWriter, req *http.Request) {
	id := path.Base(req.URL.Path)
	sw, err := s.ByID(req.Context(), id)
	if err != nil {
		ln.Error(req.Context(), err)
		http.Error(rw, "can't get data", http.StatusInternalServerError)
		return
	}

	json.NewEncoder(rw).Encode(sw)
}

func (s *Switches) Current(rw http.ResponseWriter, req *http.Request) {
	var result Switch
	res, err := r.Table("switches").
		OrderBy(r.Desc("started_at")).
		Limit(1).
		Run(s.session)
	if err != nil {
		ln.Error(req.Context(), err)
		http.Error(rw, "can't get data", http.StatusInternalServerError)
		return
	}

	err = res.One(&result)
	if err != nil {
		panic(err)
	}

	switch req.Header.Get("Accept") {
	case "text/plain":
		http.Error(rw, result.Who, http.StatusOK)
		return
	default:
		json.NewEncoder(rw).Encode(result)
	}
}

func (s *Switches) GetSwitches(rw http.ResponseWriter, req *http.Request) {
	var (
		limit = 40
		page  = 0
	)
	q := req.URL.Query()

	if val := q.Get("limit"); val != "" {
		i, err := strconv.Atoi(val)
		if err != nil {
			http.Error(rw, "limit is bad: "+err.Error(), http.StatusBadRequest)
			return
		}
		limit = i
	}

	if val := q.Get("page"); val != "" {
		i, err := strconv.Atoi(val)
		if err != nil {
			http.Error(rw, "page is bad: "+err.Error(), http.StatusBadRequest)
			return
		}
		page = i
	}

	switches, err := s.Get(req.Context(), limit, page)
	if err != nil {
		ln.Error(req.Context(), err)
		http.Error(rw, "can't get data", http.StatusInternalServerError)
		return
	}

	json.NewEncoder(rw).Encode(switches)
}

func (s *Switches) RegisterSwitch(rw http.ResponseWriter, req *http.Request) {
	who, err := ioutil.ReadAll(req.Body)
	defer req.Body.Close()
	if err != nil {
		http.Error(rw, err.Error(), http.StatusBadRequest)
		return
	}

	last, current, err := s.Switch(req.Context(), string(who))
	if err != nil {
		ln.Error(req.Context(), err)
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}

	json.NewEncoder(rw).Encode(struct {
		Last    Switch `json:"last"`
		Current Switch `json:"current"`
	}{
		Last:    last,
		Current: current,
	})
}