// SPDX-License-Identifier: AGPL-3.0-only
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, version 3.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>

package handler

import (
	"errors"
	"net/http"
	"strconv"

	"github.com/labstack/echo/v4"
	"github.com/trim21/errgo"

	"github.com/bangumi/server/domain/gerr"
	"github.com/bangumi/server/internal/episode"
	"github.com/bangumi/server/internal/pkg/generic/slice"
	"github.com/bangumi/server/internal/pkg/null"
	"github.com/bangumi/server/internal/subject"
	"github.com/bangumi/server/web/accessor"
	"github.com/bangumi/server/web/req"
	"github.com/bangumi/server/web/res"
)

func (h Handler) GetEpisode(c echo.Context) error {
	u := accessor.GetFromCtx(c)

	id, err := req.ParseID(c.Param("id"))
	if err != nil {
		return err
	}

	e, err := h.episode.Get(c.Request().Context(), id)
	if err != nil {
		if errors.Is(err, gerr.ErrNotFound) {
			return res.ErrNotFound
		}

		return errgo.Wrap(err, "failed to get episode")
	}

	_, err = h.subject.Get(c.Request().Context(), e.SubjectID, subject.Filter{
		NSFW: null.Bool{Value: false, Set: !u.AllowNSFW()},
	})
	if err != nil {
		if errors.Is(err, gerr.ErrNotFound) {
			return res.ErrNotFound
		}

		return errgo.Wrap(err, "failed to find subject of episode")
	}

	return c.JSON(http.StatusOK, res.ConvertModelEpisode(e))
}

func (h Handler) ListEpisode(c echo.Context) error {
	u := accessor.GetFromCtx(c)

	page, err := req.GetPageQuery(c, req.EpisodeDefaultLimit, req.EpisodeMaxLimit)
	if err != nil {
		return err
	}

	epType, err := req.ParseEpTypeOptional(c.QueryParam("type"))
	if err != nil {
		return err
	}

	subjectID, err := req.ParseID(c.QueryParam("subject_id"))
	if err != nil {
		return err
	}
	if subjectID == 0 {
		return res.BadRequest("missing required query `subject_id`")
	}

	_, err = h.subject.Get(c.Request().Context(), subjectID, subject.Filter{
		NSFW: null.Bool{Value: false, Set: !u.AllowNSFW()}})
	if err != nil {
		if errors.Is(err, gerr.ErrNotFound) {
			return res.ErrNotFound
		}
		return errgo.Wrap(err, "failed to get subject")
	}

	filter := episode.Filter{Type: null.NewFromPtr(epType)}

	count, err := h.episode.Count(c.Request().Context(), subjectID, filter)
	if err != nil {
		return errgo.Wrap(err, "failed to count episode")
	}

	if count == 0 {
		return c.JSON(http.StatusOK, res.Paged{
			Limit:  page.Limit,
			Offset: page.Offset,
			Data:   res.EmptySlice(),
			Total:  count,
		})
	}

	if int64(page.Offset) > count {
		return res.BadRequest("offset should be less than or equal to " + strconv.FormatInt(count, 10))
	}

	episodes, err := h.episode.List(c.Request().Context(), subjectID, filter, page.Limit, page.Offset)
	if err != nil {
		return errgo.Wrap(err, "failed to list episode")
	}

	return c.JSON(http.StatusOK, res.PagedG[res.Episode]{
		Limit:  page.Limit,
		Offset: page.Offset,
		Data:   slice.Map(episodes, res.ConvertModelEpisode),
		Total:  count,
	})
}
