package repo

import (
	"context"
	"strings"
	"time"

	"github.com/google/uuid"
	"github.com/hay-kot/homebox/backend/internal/data/ent"
	"github.com/hay-kot/homebox/backend/internal/data/ent/group"
	"github.com/hay-kot/homebox/backend/internal/data/ent/groupinvitationtoken"
)

type GroupRepository struct {
	db *ent.Client
}

type (
	Group struct {
		ID        uuid.UUID `json:"id,omitempty"`
		Name      string    `json:"name,omitempty"`
		CreatedAt time.Time `json:"createdAt,omitempty"`
		UpdatedAt time.Time `json:"updatedAt,omitempty"`
		Currency  string    `json:"currency,omitempty"`
	}

	GroupUpdate struct {
		Name     string `json:"name"`
		Currency string `json:"currency"`
	}

	GroupInvitationCreate struct {
		Token     []byte    `json:"-"`
		ExpiresAt time.Time `json:"expiresAt"`
		Uses      int       `json:"uses"`
	}

	GroupInvitation struct {
		ID        uuid.UUID `json:"id"`
		ExpiresAt time.Time `json:"expiresAt"`
		Uses      int       `json:"uses"`
		Group     Group     `json:"group"`
	}
	GroupStatistics struct {
		TotalUsers     int `json:"totalUsers"`
		TotalItems     int `json:"totalItems"`
		TotalLocations int `json:"totalLocations"`
		TotalLabels    int `json:"totalLabels"`
	}
)

var (
	mapToGroupErr = mapTErrFunc(mapToGroup)
)

func mapToGroup(g *ent.Group) Group {
	return Group{
		ID:        g.ID,
		Name:      g.Name,
		CreatedAt: g.CreatedAt,
		UpdatedAt: g.UpdatedAt,
		Currency:  strings.ToUpper(g.Currency.String()),
	}
}

var (
	mapToGroupInvitationErr = mapTErrFunc(mapToGroupInvitation)
)

func mapToGroupInvitation(g *ent.GroupInvitationToken) GroupInvitation {
	return GroupInvitation{
		ID:        g.ID,
		ExpiresAt: g.ExpiresAt,
		Uses:      g.Uses,
		Group:     mapToGroup(g.Edges.Group),
	}
}

func (r *GroupRepository) GroupStatistics(ctx context.Context, GID uuid.UUID) (GroupStatistics, error) {
	q := `
		SELECT
			(SELECT COUNT(*) FROM users WHERE group_users = ?) AS total_users,
			(SELECT COUNT(*) FROM items WHERE group_items = ? AND items.archived = false) AS total_items,
			(SELECT COUNT(*) FROM locations WHERE group_locations = ?) AS total_locations,
			(SELECT COUNT(*) FROM labels WHERE group_labels = ?) AS total_labels
`
	var stats GroupStatistics
	row := r.db.Sql().QueryRowContext(ctx, q, GID, GID, GID, GID)

	err := row.Scan(&stats.TotalUsers, &stats.TotalItems, &stats.TotalLocations, &stats.TotalLabels)
	if err != nil {
		return GroupStatistics{}, err
	}

	return stats, nil
}

func (r *GroupRepository) GroupCreate(ctx context.Context, name string) (Group, error) {
	return mapToGroupErr(r.db.Group.Create().
		SetName(name).
		Save(ctx))
}

func (r *GroupRepository) GroupUpdate(ctx context.Context, ID uuid.UUID, data GroupUpdate) (Group, error) {
	currency := group.Currency(strings.ToLower(data.Currency))

	entity, err := r.db.Group.UpdateOneID(ID).
		SetName(data.Name).
		SetCurrency(currency).
		Save(ctx)

	return mapToGroupErr(entity, err)
}

func (r *GroupRepository) GroupByID(ctx context.Context, id uuid.UUID) (Group, error) {
	return mapToGroupErr(r.db.Group.Get(ctx, id))
}

func (r *GroupRepository) InvitationGet(ctx context.Context, token []byte) (GroupInvitation, error) {
	return mapToGroupInvitationErr(r.db.GroupInvitationToken.Query().
		Where(groupinvitationtoken.Token(token)).
		WithGroup().
		Only(ctx))
}

func (r *GroupRepository) InvitationCreate(ctx context.Context, groupID uuid.UUID, invite GroupInvitationCreate) (GroupInvitation, error) {
	entity, err := r.db.GroupInvitationToken.Create().
		SetGroupID(groupID).
		SetToken(invite.Token).
		SetExpiresAt(invite.ExpiresAt).
		SetUses(invite.Uses).
		Save(ctx)

	if err != nil {
		return GroupInvitation{}, err
	}

	return r.InvitationGet(ctx, entity.Token)
}

func (r *GroupRepository) InvitationUpdate(ctx context.Context, id uuid.UUID, uses int) error {
	_, err := r.db.GroupInvitationToken.UpdateOneID(id).SetUses(uses).Save(ctx)
	return err
}

// InvitationPurge removes all expired invitations or those that have been used up.
// It returns the number of deleted invitations.
func (r *GroupRepository) InvitationPurge(ctx context.Context) (amount int, err error) {
	q := r.db.GroupInvitationToken.Delete()
	q.Where(groupinvitationtoken.Or(
		groupinvitationtoken.ExpiresAtLT(time.Now()),
		groupinvitationtoken.UsesLTE(0),
	))

	return q.Exec(ctx)
}