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

package home

import (
	"context"
	"io"
	"net/http"
	"strconv"

	"github.com/jackc/pgx/v4"

	"dev.tandem.ws/tandem/camper/pkg/auth"
	"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/template"
)

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

		switch head {
		case "":
			switch r.Method {
			case http.MethodPost:
				addSlide(w, r, user, company, conn)
			default:
				httplib.MethodNotAllowed(w, r, http.MethodGet)
			}
		case "new":
			switch r.Method {
			case http.MethodGet:
				f := newSlideForm()
				f.MustRender(w, r, user, company)
			default:
				httplib.MethodNotAllowed(w, r, http.MethodGet)
			}
		default:
			id, err := strconv.Atoi(head)
			if err != nil {
				http.NotFound(w, r)
			}
			f := newSlideForm()
			if err := f.FillFromDatabase(r.Context(), conn, id); err != nil {
				if database.ErrorIsNotFound(err) {
					http.NotFound(w, r)
					return
				}
				panic(err)
			}

			var langTag string
			langTag, r.URL.Path = httplib.ShiftPath(r.URL.Path)

			switch langTag {
			case "":
				switch r.Method {
				case http.MethodGet:
					f.MustRender(w, r, user, company)
				case http.MethodPut:
					editSlide(w, r, user, company, conn, f)
				case http.MethodDelete:
					deleteSlide(w, r, user, conn, id)
				default:
					httplib.MethodNotAllowed(w, r, http.MethodGet, http.MethodPut)
				}
			default:
				loc, ok := h.locales.Get(langTag)
				if !ok {
					http.NotFound(w, r)
					return
				}
				l10n := newSlideL10nForm(f, loc)
				if err := l10n.FillFromDatabase(r.Context(), conn); err != nil {
					panic(err)
				}
				switch r.Method {
				case http.MethodGet:
					l10n.MustRender(w, r, user, company)
				case http.MethodPut:
					editSlideL10n(w, r, user, company, conn, l10n)
				default:
					httplib.MethodNotAllowed(w, r, http.MethodGet, http.MethodPut)
				}
			}
		}
	})
}

type carouselSlide struct {
	Media   string
	Caption string
}

func mustCollectCarouselSlides(ctx context.Context, company *auth.Company, conn *database.Conn, loc *locale.Locale) []*carouselSlide {
	rows, err := conn.Query(ctx, `
		select coalesce(i18n.caption, slide.caption) as l10_caption
		     , media.path
		from home_carousel as slide
		    join media using (media_id)
		    left join home_carousel_i18n as i18n on i18n.media_id = slide.media_id and lang_tag = $1
		where media.company_id = $2
	`, loc.Language, company.ID)
	if err != nil {
		panic(err)
	}
	defer rows.Close()

	var carousel []*carouselSlide
	for rows.Next() {
		slide := &carouselSlide{}
		err = rows.Scan(&slide.Caption, &slide.Media)
		if err != nil {
			panic(err)
		}
		carousel = append(carousel, slide)
	}
	if rows.Err() != nil {
		panic(rows.Err())
	}

	return carousel
}

type slideEntry struct {
	carouselSlide
	ID           int
	Translations []*translation
}

type translation struct {
	Language string
	Endonym  string
	Missing  bool
}

func collectSlideEntries(ctx context.Context, company *auth.Company, conn *database.Conn) ([]*slideEntry, error) {
	rows, err := conn.Query(ctx, `
		select media_id
		     , media.path
		     , caption
		     , array_agg((lang_tag, endonym, not exists (select 1 from home_carousel_i18n as i18n where i18n.media_id = home_carousel.media_id and i18n.lang_tag = language.lang_tag)) order by endonym)
		from home_carousel
		    join media using (media_id)
		    join company using (company_id)
		   , language
		where lang_tag <> default_lang_tag
		  and language.selectable
		  and media.company_id = $1
		group by media_id
		       , media.path
		       , caption
		order by caption
	`, pgx.QueryResultFormats{pgx.BinaryFormatCode}, company.ID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var slides []*slideEntry
	for rows.Next() {
		slide := &slideEntry{}
		var translations database.RecordArray
		if err = rows.Scan(&slide.ID, &slide.Media, &slide.Caption, &translations); err != nil {
			return nil, err
		}
		for _, el := range translations.Elements {
			slide.Translations = append(slide.Translations, &translation{
				el.Fields[0].Get().(string),
				el.Fields[1].Get().(string),
				el.Fields[2].Get().(bool),
			})
		}
		slides = append(slides, slide)
	}

	return slides, nil
}

func addSlide(w http.ResponseWriter, r *http.Request, user *auth.User, company *auth.Company, conn *database.Conn) {
	f := newSlideForm()
	editSlide(w, r, user, company, conn, f)
}

func editSlide(w http.ResponseWriter, r *http.Request, user *auth.User, company *auth.Company, conn *database.Conn, f *slideForm) {
	f.process(w, r, user, company, false, func(ctx context.Context) {
		bytes := f.MustReadAllMedia()
		if bytes == nil {
			conn.MustExec(ctx, "select add_home_carousel_slide($1, $2)", f.ID, f.Caption)
		} else {
			tx := conn.MustBegin(ctx)
			defer tx.Rollback(ctx)
			f.ID = tx.MustGetInt(ctx, "select add_media($1, $2, $3, $4)", company.ID, f.Media.Filename(), f.Media.ContentType, bytes)
			tx.MustExec(ctx, "select add_home_carousel_slide($1, $2)", f.ID, f.Caption)
			tx.MustCommit(ctx)
		}
	})
}

func deleteSlide(w http.ResponseWriter, r *http.Request, user *auth.User, conn *database.Conn, id int) {
	if err := user.VerifyCSRFToken(r); err != nil {
		http.Error(w, err.Error(), http.StatusForbidden)
		return
	}
	conn.MustExec(r.Context(), "select remove_home_carousel_slide($1)", id)
	httplib.Redirect(w, r, "/admin/home", http.StatusSeeOther)
}

type slideForm struct {
	ID      int
	Media   *form.File
	Caption *form.Input
}

func newSlideForm() *slideForm {
	return &slideForm{
		Media: &form.File{
			Name:    "media",
			MaxSize: 1 << 20,
		},
		Caption: &form.Input{
			Name: "caption",
		},
	}
}

func (f *slideForm) FillFromDatabase(ctx context.Context, conn *database.Conn, id int) error {
	f.ID = id
	row := conn.QueryRow(ctx, `
		select caption
		     , media.path
		from home_carousel
		join media using (media_id)
		where media_id = $1
	`, id)
	return row.Scan(&f.Caption.Val, &f.Media.Val)
}

func (f *slideForm) process(w http.ResponseWriter, r *http.Request, user *auth.User, company *auth.Company, mediaRequired bool, act func(ctx context.Context)) {
	if err := f.Parse(w, r); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	defer f.Close()
	if err := user.VerifyCSRFToken(r); err != nil {
		http.Error(w, err.Error(), http.StatusForbidden)
		return
	}
	if !f.Valid(user.Locale, mediaRequired) {
		if !httplib.IsHTMxRequest(r) {
			w.WriteHeader(http.StatusUnprocessableEntity)
		}
		f.MustRender(w, r, user, company)
		return
	}
	act(r.Context())
	httplib.Redirect(w, r, "/admin/home", http.StatusSeeOther)
}

func (f *slideForm) Parse(w http.ResponseWriter, r *http.Request) error {
	maxSize := f.Media.MaxSize + 1024
	r.Body = http.MaxBytesReader(w, r.Body, maxSize)
	if err := r.ParseMultipartForm(maxSize); err != nil {
		return err
	}
	f.Caption.FillValue(r)
	if err := f.Media.FillValue(r); err != nil {
		return err
	}
	return nil
}

func (f *slideForm) Close() error {
	return f.Media.Close()
}

func (f *slideForm) Valid(l *locale.Locale, mediaRequired bool) bool {
	v := form.NewValidator(l)
	if f.HasMediaFile() {
		v.CheckImageFile(f.Media, l.GettextNoop("File must be a valid PNG or JPEG image."))
	} else {
		v.Check(f.Media, !mediaRequired, l.GettextNoop("Slide image can not be empty."))
	}
	return v.AllOK
}

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

func (f *slideForm) HasMediaFile() bool {
	return f.Media.HasData()
}

func (f *slideForm) MustReadAllMedia() []byte {
	if !f.HasMediaFile() {
		return nil
	}
	bytes, err := io.ReadAll(f.Media)
	if err != nil {
		panic(err)
	}
	return bytes
}