/*
 * SPDX-FileCopyrightText: 2023 jordi fita mas <jfita@peritasoft.com>
 * SPDX-License-Identifier: AGPL-3.0-only
 */

package campsite

import (
	"context"
	"net/http"
	"time"

	"github.com/jackc/pgx/v4"

	"dev.tandem.ws/tandem/camper/pkg/auth"
	"dev.tandem.ws/tandem/camper/pkg/campsite/types"
	"dev.tandem.ws/tandem/camper/pkg/database"
	"dev.tandem.ws/tandem/camper/pkg/form"
	httplib "dev.tandem.ws/tandem/camper/pkg/http"
	"dev.tandem.ws/tandem/camper/pkg/locale"
	"dev.tandem.ws/tandem/camper/pkg/season"
	"dev.tandem.ws/tandem/camper/pkg/template"
)

type AdminHandler struct {
	types *types.AdminHandler
}

func NewAdminHandler() *AdminHandler {
	return &AdminHandler{
		types: types.NewAdminHandler(),
	}
}

func (h *AdminHandler) Handler(user *auth.User, company *auth.Company, conn *database.Conn) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		var head string
		head, r.URL.Path = httplib.ShiftPath(r.URL.Path)

		switch head {
		case "new":
			switch r.Method {
			case http.MethodGet:
				f := newCampsiteForm(r.Context(), conn, company)
				f.MustRender(w, r, user, company)
			default:
				httplib.MethodNotAllowed(w, r, http.MethodGet)
			}
		case "types":
			h.types.Handler(user, company, conn).ServeHTTP(w, r)
		case "":
			switch r.Method {
			case http.MethodGet:
				serveCampsiteIndex(w, r, user, company, conn)
			case http.MethodPost:
				addCampsite(w, r, user, company, conn)
			default:
				httplib.MethodNotAllowed(w, r, http.MethodGet, http.MethodPost)
			}
		default:
			f := newCampsiteForm(r.Context(), conn, company)
			if err := f.FillFromDatabase(r.Context(), conn, company, head); err != nil {
				if database.ErrorIsNotFound(err) {
					http.NotFound(w, r)
					return
				}
				panic(err)
			}

			head, r.URL.Path = httplib.ShiftPath(r.URL.Path)
			switch head {
			case "":
				switch r.Method {
				case http.MethodGet:
					f.MustRender(w, r, user, company)
				case http.MethodPut:
					editCampsite(w, r, user, company, conn, f)
				default:
					httplib.MethodNotAllowed(w, r, http.MethodGet, http.MethodPut)
				}
			case "slides":
				h.carouselHandler(user, company, conn, f.Label.Val).ServeHTTP(w, r)
			case "features":
				h.featuresHandler(user, company, conn, f.Label.Val).ServeHTTP(w, r)
			default:
				http.NotFound(w, r)
			}
		}
	}
}

func serveCampsiteIndex(w http.ResponseWriter, r *http.Request, user *auth.User, company *auth.Company, conn *database.Conn) {
	page := newCampsiteIndex()
	if err := page.Parse(r); err != nil {
		panic(err)
	}
	var err error
	page.Campsites, err = collectCampsiteEntries(r.Context(), company, conn, page.From.Date(), page.To.Date())
	if err != nil {
		panic(err)
	}
	page.Months = collectMonths(page.From.Date(), page.To.Date())
	page.MustRender(w, r, user, company)
}

func collectCampsiteEntries(ctx context.Context, company *auth.Company, conn *database.Conn, from time.Time, to time.Time) ([]*campsiteEntry, error) {
	rows, err := conn.Query(ctx, `
		select campsite.label
		     , campsite_type.name
		     , campsite.active
		from campsite
		join campsite_type using (campsite_type_id)
		where campsite.company_id = $1
		order by label`, company.ID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	byLabel := make(map[string]*campsiteEntry)
	var campsites []*campsiteEntry
	for rows.Next() {
		entry := &campsiteEntry{}
		if err = rows.Scan(&entry.Label, &entry.Type, &entry.Active); err != nil {
			return nil, err
		}
		campsites = append(campsites, entry)
		byLabel[entry.Label] = entry
	}

	if err := collectBookingEntries(ctx, company, conn, from, to, byLabel); err != nil {
		return nil, err
	}

	return campsites, nil
}

func collectBookingEntries(ctx context.Context, company *auth.Company, conn *database.Conn, from time.Time, to time.Time, campsites map[string]*campsiteEntry) error {
	lastDay := to.AddDate(0, 1, 0)
	rows, err := conn.Query(ctx, `
		select campsite.label
		     , lower(booking_campsite.stay * daterange($2::date, $3::date))
		     , holder_name
		     , booking_status
			 , upper(booking_campsite.stay * daterange($2::date, $3::date)) - lower(booking_campsite.stay * daterange($2::date, $3::date))
			 , booking_campsite.stay &> daterange($2::date, $3::date) 
			 , booking_campsite.stay &< daterange($2::date, $3::date) 
		from booking_campsite
		join booking using (booking_id)
		join campsite using (campsite_id)
		where booking.company_id = $1
		  and booking_campsite.stay && daterange($2::date, $3::date)
		order by label`, company.ID, from, lastDay)
	if err != nil {
		return err
	}
	defer rows.Close()

	for rows.Next() {
		entry := &bookingEntry{}
		var label string
		var date time.Time
		if err = rows.Scan(&label, &date, &entry.Holder, &entry.Status, &entry.Nights, &entry.Begin, &entry.End); err != nil {
			return err
		}
		campsite := campsites[label]
		if campsite != nil {
			if campsite.Bookings == nil {
				campsite.Bookings = make(map[time.Time]*bookingEntry)
			}
			campsite.Bookings[date] = entry
		}
	}

	return nil
}

type campsiteEntry struct {
	Label    string
	Type     string
	Active   bool
	Bookings map[time.Time]*bookingEntry
}

type bookingEntry struct {
	Holder string
	Status string
	Nights int
	Begin  bool
	End    bool
}

type campsiteIndex struct {
	From      *form.Month
	To        *form.Month
	Campsites []*campsiteEntry
	Months    []*Month
}

func newCampsiteIndex() *campsiteIndex {
	now := time.Now()
	from := time.Date(now.Year(), now.Month(), 1, 0, 0, 0, 0, time.UTC)
	to := from.AddDate(0, 3, 0)
	return &campsiteIndex{
		From: &form.Month{
			Name:  "from",
			Year:  from.Year(),
			Month: from.Month(),
		},
		To: &form.Month{
			Name:  "to",
			Year:  to.Year(),
			Month: to.Month(),
		},
	}
}

func (page *campsiteIndex) Parse(r *http.Request) error {
	if err := r.ParseForm(); err != nil {
		return err
	}
	page.From.FillValue(r)
	page.To.FillValue(r)
	return nil
}

type Month struct {
	Year  int
	Month time.Month
	Name  string
	Days  []time.Time
	Spans []*Span
}

type Span struct {
	Weekend bool
	Count   int
}

func isWeekend(t time.Time) bool {
	switch t.Weekday() {
	case time.Saturday, time.Sunday:
		return true
	default:
		return false
	}
}

func collectMonths(from time.Time, to time.Time) []*Month {
	current := time.Date(from.Year(), from.Month(), 1, 0, 0, 0, 0, time.UTC)
	numMonths := (to.Year()-from.Year())*12 + int(to.Month()) - int(from.Month()) + 1
	var months []*Month
	for i := 0; i < numMonths; i++ {
		span := &Span{
			Weekend: isWeekend(current),
		}
		month := &Month{
			Year:  current.Year(),
			Month: current.Month(),
			Name:  season.LongMonthNames[current.Month()-1],
			Days:  make([]time.Time, 0, 31),
			Spans: make([]*Span, 0, 10),
		}
		month.Spans = append(month.Spans, span)
		for current.Month() == month.Month {
			month.Days = append(month.Days, current)
			if span.Weekend != isWeekend(current) {
				span = &Span{
					Weekend: !span.Weekend,
				}
				month.Spans = append(month.Spans, span)
			}
			span.Count = span.Count + 1
			current = current.AddDate(0, 0, 1)
		}
		months = append(months, month)
	}
	return months
}

func (page *campsiteIndex) MustRender(w http.ResponseWriter, r *http.Request, user *auth.User, company *auth.Company) {
	template.MustRenderAdminFiles(w, r, user, company, page, "campsite/index.gohtml", "web/templates/campground_map.svg")
}

func addCampsite(w http.ResponseWriter, r *http.Request, user *auth.User, company *auth.Company, conn *database.Conn) {
	f := newCampsiteForm(r.Context(), conn, company)
	processCampsiteForm(w, r, user, company, conn, f, func(ctx context.Context, tx *database.Tx) error {
		var err error
		f.ID, err = tx.AddCampsite(ctx, f.CampsiteType.Int(), f.Label.Val, f.Info1[f.DefaultLang].Val, f.Info2[f.DefaultLang].Val)
		if err != nil {
			return err
		}
		return translateCampsite(ctx, tx, company, f)
	})
	httplib.Redirect(w, r, "/admin/campsites", http.StatusSeeOther)
}

func translateCampsite(ctx context.Context, tx *database.Tx, company *auth.Company, f *campsiteForm) error {
	for lang := range company.Locales {
		l := lang.String()
		if l == f.DefaultLang {
			continue
		}
		if err := tx.TranslateCampsite(ctx, f.ID, lang, f.Info1[l].Val, f.Info2[l].Val); err != nil {
			return err
		}
	}
	return nil
}

func editCampsite(w http.ResponseWriter, r *http.Request, user *auth.User, company *auth.Company, conn *database.Conn, f *campsiteForm) {
	processCampsiteForm(w, r, user, company, conn, f, func(ctx context.Context, tx *database.Tx) error {
		if err := tx.EditCampsite(ctx, f.ID, f.CampsiteType.Int(), f.Label.Val, f.Info1[f.DefaultLang].Val, f.Info2[f.DefaultLang].Val, f.Active.Checked); err != nil {
			return err
		}
		return translateCampsite(ctx, tx, company, f)
	})
	httplib.Redirect(w, r, "/admin/campsites", http.StatusSeeOther)
}

func processCampsiteForm(w http.ResponseWriter, r *http.Request, user *auth.User, company *auth.Company, conn *database.Conn, f *campsiteForm, act func(ctx context.Context, tx *database.Tx) error) {
	if ok, err := form.Handle(f, w, r, user); err != nil {
		return
	} else if !ok {
		f.MustRender(w, r, user, company)
		return
	}

	tx := conn.MustBegin(r.Context())
	defer tx.Rollback(r.Context())
	if err := act(r.Context(), tx); err != nil {
		panic(err)
	}
	tx.MustCommit(r.Context())
	httplib.Redirect(w, r, "/admin/campsites", http.StatusSeeOther)
}

type campsiteForm struct {
	DefaultLang  string
	ID           int
	CurrentLabel string
	Active       *form.Checkbox
	CampsiteType *form.Select
	Label        *form.Input
	Info1        form.I18nInput
	Info2        form.I18nInput
}

func newCampsiteForm(ctx context.Context, conn *database.Conn, company *auth.Company) *campsiteForm {
	campsiteTypes := form.MustGetOptions(ctx, conn, "select campsite_type_id::text, name from campsite_type where active")
	return &campsiteForm{
		DefaultLang: company.DefaultLanguage.String(),
		Active: &form.Checkbox{
			Name:    "active",
			Checked: true,
		},
		CampsiteType: &form.Select{
			Name:    "description",
			Options: campsiteTypes,
		},
		Label: &form.Input{
			Name: "label",
		},
		Info1: form.NewI18nInput(company.Locales, "info1"),
		Info2: form.NewI18nInput(company.Locales, "info2"),
	}
}

func (f *campsiteForm) FillFromDatabase(ctx context.Context, conn *database.Conn, company *auth.Company, label string) error {
	f.CurrentLabel = label
	var info1 database.RecordArray
	var info2 database.RecordArray
	row := conn.QueryRow(ctx, `
		select campsite_id
		     , array[campsite_type_id::text]
		     , label
		     , campsite.info1::text
		     , campsite.info2::text
		     , active
		     , array_agg((lang_tag, i18n.info1::text))
		     , array_agg((lang_tag, i18n.info2::text))
		from campsite
        left join campsite_i18n as i18n using (campsite_id)
		where company_id = $1
		  and label = $2
		group by campsite_id
		       , campsite_type_id
		       , label
		       , campsite.info1::text
		       , campsite.info2::text
		       , active
	`, pgx.QueryResultFormats{pgx.BinaryFormatCode}, company.ID, label)
	if err := row.Scan(&f.ID, &f.CampsiteType.Selected, &f.Label.Val, &f.Info1[f.DefaultLang].Val, &f.Info2[f.DefaultLang].Val, &f.Active.Checked, &info1, &info2); err != nil {
		return err
	}
	if err := f.Info1.FillArray(info1); err != nil {
		return err
	}
	if err := f.Info2.FillArray(info2); err != nil {
		return err
	}
	return nil
}

func (f *campsiteForm) Parse(r *http.Request) error {
	if err := r.ParseForm(); err != nil {
		return err
	}
	f.Active.FillValue(r)
	f.CampsiteType.FillValue(r)
	f.Label.FillValue(r)
	f.Info1.FillValue(r)
	f.Info2.FillValue(r)
	return nil
}

func (f *campsiteForm) Valid(l *locale.Locale) bool {
	v := form.NewValidator(l)
	v.CheckSelectedOptions(f.CampsiteType, l.GettextNoop("Selected campsite type is not valid."))
	v.CheckRequired(f.Label, l.GettextNoop("Label can not be empty."))
	return v.AllOK
}

func (f *campsiteForm) MustRender(w http.ResponseWriter, r *http.Request, user *auth.User, company *auth.Company) {
	template.MustRenderAdmin(w, r, user, company, "campsite/form.gohtml", f)
}