package activitypub

import (
	"net/http"
	"strconv"

	webutils "git.mstar.dev/mstar/goutils/http"
	"git.mstar.dev/mstar/goutils/other"
	"github.com/rs/zerolog/hlog"
	"gorm.io/gorm"

	"git.mstar.dev/mstar/linstrom/storage-new/dbgen"
)

func handleUndo(w http.ResponseWriter, r *http.Request, object map[string]any) {
	log := hlog.FromRequest(r)
	_ = object["id"].(string)
	_, ok := object["actor"].(string)
	if !ok {
		webutils.ProblemDetails(
			w,
			http.StatusBadRequest,
			"/errors/bad-request-data",
			"Bad activity data",
			other.IntoPointer(`Request data needs to contain a field "actor" with a string value`),
			nil,
		)
		return
	}
	rawTarget, ok := object["object"]
	if !ok {
		webutils.ProblemDetails(
			w,
			http.StatusBadRequest,
			"/errors/bad-request-data",
			"Bad activity data",
			other.IntoPointer(`Request data needs to contain a field "object"`),
			nil,
		)
		return
	}
	// FIXME: Also handle other undo cases, such as follows
	var targetObjectId string
	var targetObjectType string
	// I *think* the spec says that this must be an object. Not sure though
	switch target := rawTarget.(type) {
	case string:
		targetObjectId = target
	case map[string]any:
		objType, ok := target["type"].(string)
		if !ok {
			webutils.ProblemDetails(
				w,
				http.StatusBadRequest,
				"/errors/bad-request-data",
				"Bad activity data",
				other.IntoPointer(`Target object does not have a type`),
				nil,
			)
			return
		}
		targetObjectType = objType
		targetObjectId, ok = target["id"].(string)
		if !ok {
			webutils.ProblemDetails(
				w,
				http.StatusBadRequest,
				"/errors/bad-request-data",
				"Bad activity data",
				other.IntoPointer(`Missing id in undone object`),
				nil,
			)
			return
		}
	default:
		webutils.ProblemDetails(
			w,
			http.StatusBadRequest,
			"/errors/bad-request-data",
			"Bad activity data",
			other.IntoPointer(`Request data needs to contain a field "object" of type string or object`),
			nil,
		)
		return
	}
	switch targetObjectType {
	case "Like":
		undoLike(w, r, object, targetObjectId)
	case "Follow":
		undoFollow(w, r, object, targetObjectId)
	default:
		log.Error().
			Str("undo-target-type", targetObjectType).
			Msg("Unknown/unimplemented undo target type")
		webutils.ProblemDetailsStatusOnly(w, http.StatusInternalServerError)
	}
}

func undoLike(w http.ResponseWriter, r *http.Request, object map[string]any, targetId string) {
	log := hlog.FromRequest(r)
	act, err := dbgen.Activity.Where(dbgen.Activity.Id.Eq(targetId), dbgen.Activity.Type.Eq("like")).
		First()
	switch err {
	case gorm.ErrRecordNotFound:
		return
	case nil:
	default:
		log.Error().
			Err(err).
			Str("activity-id", targetId).
			Msg("Error while looking for like activity")
		webutils.ProblemDetailsStatusOnly(w, http.StatusInternalServerError)
		return
	}
	reactionId := uint(other.Must(strconv.ParseUint(act.ObjectId, 10, 64)))
	reaction, err := dbgen.Reaction.Where(dbgen.Reaction.ID.Eq(reactionId)).First()
	switch err {
	case gorm.ErrRecordNotFound:
		return
	case nil:
	default:
		log.Error().
			Err(err).
			Str("activity-id", targetId).
			Msg("Error while looking for find activity")
		webutils.ProblemDetailsStatusOnly(w, http.StatusInternalServerError)
		return
	}
	tx := dbgen.Q.Begin()
	_, err = tx.Activity.Where(dbgen.Activity.Id.Eq(act.Id)).Delete()
	if err != nil {
		_ = tx.Rollback()
		log.Error().Err(err).Str("activity-id", act.Id).Msg("Failed to delete activity on undo")
		webutils.ProblemDetailsStatusOnly(w, http.StatusInternalServerError)
		return
	}
	_, err = tx.Reaction.Where(dbgen.Reaction.ID.Eq(reaction.ID)).Delete()
	if err != nil {
		_ = tx.Rollback()
		log.Error().
			Err(err).
			Uint("reaction-id", reaction.ID).
			Msg("Failed to delete reaction on undo")
		webutils.ProblemDetailsStatusOnly(w, http.StatusInternalServerError)
		return
	}
	err = tx.Commit()
	if err != nil {
		log.Error().Err(err).Msg("Failed to delete reaction and activity")
		webutils.ProblemDetailsStatusOnly(w, http.StatusInternalServerError)
	}
}

func undoFollow(w http.ResponseWriter, r *http.Request, object map[string]any, targetId string) {
	log := hlog.FromRequest(r)
	act, err := dbgen.Activity.Where(dbgen.Activity.Id.Eq(targetId), dbgen.Activity.Type.Eq("follow")).
		First()
	switch err {
	case gorm.ErrRecordNotFound:
		return
	case nil:
	default:
		log.Error().
			Err(err).
			Str("activity-id", targetId).
			Msg("Error while looking for follow activity")
		webutils.ProblemDetailsStatusOnly(w, http.StatusInternalServerError)
		return
	}
	relationId := other.Must(strconv.ParseUint(act.ObjectId, 10, 64))
	tx := dbgen.Q.Begin()
	_, err = tx.Activity.Where(dbgen.Activity.Id.Eq(act.Id)).Delete()
	if err != nil {
		_ = tx.Rollback()
		log.Error().
			Err(err).
			Str("activity-id", act.Id).
			Msg("Failed to delete follow activity on undo")
		webutils.ProblemDetailsStatusOnly(w, http.StatusInternalServerError)
		return
	}
	// Delete all activities that reference the follow activity (so accept/reject if exists)
	_, err = tx.Activity.Where(dbgen.Activity.ObjectId.Eq(act.Id)).Delete()
	if err != nil {
		_ = tx.Rollback()
		log.Error().
			Err(err).
			Str("activity-id", act.Id).
			Msg("Failed to delete accept/reject activity for follow on undo")
		webutils.ProblemDetailsStatusOnly(w, http.StatusInternalServerError)
		return
	}
	_, err = tx.UserToUserRelation.Where(dbgen.UserToUserRelation.ID.Eq(relationId)).Delete()
	if err != nil {
		_ = tx.Rollback()
		log.Error().
			Err(err).
			Str("activity-id", act.Id).
			Uint64("relation-id", relationId).
			Msg("Failed to delete user-to-user relation for follow on undo")
		webutils.ProblemDetailsStatusOnly(w, http.StatusInternalServerError)
		return
	}
	err = tx.Commit()
	if err != nil {
		log.Error().Err(err).Msg("Failed to delete reaction and activity")
		webutils.ProblemDetailsStatusOnly(w, http.StatusInternalServerError)
	}
}