package service

import (
	"context"
	"sort"

	"github.com/gogf/gf/v2/errors/gerror"
	"golang.org/x/crypto/bcrypt"

	"service.xpcool.com/internal/consts"
	"service.xpcool.com/internal/dao"
	"service.xpcool.com/internal/library/response"
	"service.xpcool.com/internal/model/do"
	"service.xpcool.com/internal/model/dto"
	"service.xpcool.com/internal/model/entity"
)

// IAdminManage manages administrators.
type IAdminManage interface {
	List(context.Context, dto.PageQuery) ([]*dto.AdminItem, int, error)
	Create(context.Context, dto.AdminCreateInput) (uint64, error)
	Update(context.Context, dto.AdminUpdateInput) error
	ResetPassword(context.Context, uint64, string) error
	Delete(context.Context, uint64) error
}

// IRoleManage manages roles and their menu bindings.
type IRoleManage interface {
	List(context.Context, dto.PageQuery) ([]*dto.RoleItem, int, error)
	Create(context.Context, dto.RoleCreateInput) (uint64, error)
	Update(context.Context, dto.RoleUpdateInput) error
	Delete(context.Context, uint64) error
}

// IMenuManage manages the menu tree (menus + button permissions).
type IMenuManage interface {
	Tree(context.Context) ([]*dto.MenuNode, error)
	Create(context.Context, dto.MenuCreateInput) (uint64, error)
	Update(context.Context, dto.MenuUpdateInput) error
	Delete(context.Context, uint64) error
}

type adminManage struct{}
type roleManage struct{}
type menuManage struct{}

func NewAdminManage() IAdminManage { return &adminManage{} }
func NewRoleManage() IRoleManage   { return &roleManage{} }
func NewMenuManage() IMenuManage   { return &menuManage{} }

var (
	localAdminManage IAdminManage
	localRoleManage  IRoleManage
	localMenuManage  IMenuManage
)

func AdminManage() IAdminManage {
	if localAdminManage == nil {
		panic("AdminManage implementation not registered")
	}
	return localAdminManage
}
func RegisterAdminManage(i IAdminManage) { localAdminManage = i }
func RoleManage() IRoleManage {
	if localRoleManage == nil {
		panic("RoleManage implementation not registered")
	}
	return localRoleManage
}
func RegisterRoleManage(i IRoleManage) { localRoleManage = i }
func MenuManage() IMenuManage {
	if localMenuManage == nil {
		panic("MenuManage implementation not registered")
	}
	return localMenuManage
}
func RegisterMenuManage(i IMenuManage) { localMenuManage = i }

// ---------------------- Admin manage ----------------------

func (s *adminManage) List(ctx context.Context, q dto.PageQuery) ([]*dto.AdminItem, int, error) {
	total, err := dao.AdminUser.Ctx(ctx).Count()
	if err != nil {
		return nil, 0, gerror.Wrap(err, "count admins")
	}
	if total == 0 {
		return nil, 0, nil
	}
	var list []entity.AdminUser
	if err = dao.AdminUser.Ctx(ctx).Page(q.Page, q.Size).OrderDesc("id").Scan(&list); err != nil {
		return nil, 0, gerror.Wrap(err, "query admins")
	}
	items := make([]*dto.AdminItem, 0, len(list))
	for i := range list {
		a := &list[i]
		roleIds, roleNames, err := s.roles(ctx, a.Id)
		if err != nil {
			return nil, 0, err
		}
		items = append(items, &dto.AdminItem{
			Id: a.Id, Username: a.Username, Nickname: a.Nickname, Status: a.Status,
			RoleIds: roleIds, RoleNames: roleNames,
			CreatedAt: a.CreatedAt.Layout("2006-01-02 15:04:05"),
		})
	}
	return items, total, nil
}

func (s *adminManage) roles(ctx context.Context, adminID uint64) ([]uint64, []string, error) {
	var rels []entity.AdminUserRole
	if err := dao.AdminUserRole.Ctx(ctx).Where(do.AdminUserRole{AdminUserId: adminID}).Scan(&rels); err != nil {
		return nil, nil, gerror.Wrap(err, "query admin roles")
	}
	roleIds := make([]uint64, 0, len(rels))
	for _, r := range rels {
		roleIds = append(roleIds, r.RoleId)
	}
	if len(roleIds) == 0 {
		return roleIds, nil, nil
	}
	var roles []entity.AdminRole
	if err := dao.AdminRole.Ctx(ctx).WhereIn("id", roleIds).Scan(&roles); err != nil {
		return nil, nil, gerror.Wrap(err, "query roles")
	}
	names := make([]string, 0, len(roles))
	for _, r := range roles {
		names = append(names, r.Name)
	}
	return roleIds, names, nil
}

func (s *adminManage) Create(ctx context.Context, in dto.AdminCreateInput) (uint64, error) {
	count, err := dao.AdminUser.Ctx(ctx).Where(do.AdminUser{Username: in.Username}).Count()
	if err != nil {
		return 0, gerror.Wrap(err, "check username")
	}
	if count > 0 {
		return 0, response.Error(consts.CodeInvalidParam, "username already exists")
	}
	hash, err := bcrypt.GenerateFromPassword([]byte(in.Password), bcrypt.DefaultCost)
	if err != nil {
		return 0, gerror.Wrap(err, "hash password")
	}
	id, err := dao.AdminUser.Ctx(ctx).Data(do.AdminUser{
		Username: in.Username, PasswordHash: string(hash), Nickname: in.Nickname, Status: 1,
	}).InsertAndGetId()
	if err != nil {
		return 0, gerror.Wrap(err, "insert admin")
	}
	if err = bindAdminRoles(ctx, uint64(id), in.RoleIds); err != nil {
		return 0, err
	}
	return uint64(id), nil
}

func (s *adminManage) Update(ctx context.Context, in dto.AdminUpdateInput) error {
	data := do.AdminUser{Nickname: in.Nickname, Status: in.Status}
	if _, err := dao.AdminUser.Ctx(ctx).Where(do.AdminUser{Id: in.Id}).Data(data).Update(); err != nil {
		return gerror.Wrap(err, "update admin")
	}
	return bindAdminRoles(ctx, in.Id, in.RoleIds)
}

func (s *adminManage) ResetPassword(ctx context.Context, id uint64, password string) error {
	hash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
	if err != nil {
		return gerror.Wrap(err, "hash password")
	}
	if _, err = dao.AdminUser.Ctx(ctx).Where(do.AdminUser{Id: id}).Data(do.AdminUser{PasswordHash: string(hash)}).Update(); err != nil {
		return gerror.Wrap(err, "reset password")
	}
	return nil
}

func (s *adminManage) Delete(ctx context.Context, id uint64) error {
	if _, err := dao.AdminUser.Ctx(ctx).Where(do.AdminUser{Id: id}).Delete(); err != nil {
		return gerror.Wrap(err, "delete admin")
	}
	// 关联关系物理删除，避免唯一键残留。
	if _, err := dao.AdminUserRole.Ctx(ctx).Unscoped().Where(do.AdminUserRole{AdminUserId: id}).Delete(); err != nil {
		return gerror.Wrap(err, "delete admin role bindings")
	}
	return nil
}

// bindAdminRoles 全量重绑管理员-角色关系。
func bindAdminRoles(ctx context.Context, adminID uint64, roleIds []uint64) error {
	if _, err := dao.AdminUserRole.Ctx(ctx).Unscoped().Where(do.AdminUserRole{AdminUserId: adminID}).Delete(); err != nil {
		return gerror.Wrap(err, "clear admin roles")
	}
	for _, rid := range roleIds {
		if _, err := dao.AdminUserRole.Ctx(ctx).Data(do.AdminUserRole{AdminUserId: adminID, RoleId: rid}).Insert(); err != nil {
			return gerror.Wrap(err, "bind admin role")
		}
	}
	return nil
}

// ---------------------- Role manage ----------------------

func (s *roleManage) List(ctx context.Context, q dto.PageQuery) ([]*dto.RoleItem, int, error) {
	total, err := dao.AdminRole.Ctx(ctx).Count()
	if err != nil {
		return nil, 0, gerror.Wrap(err, "count roles")
	}
	if total == 0 {
		return nil, 0, nil
	}
	var list []entity.AdminRole
	if err = dao.AdminRole.Ctx(ctx).Page(q.Page, q.Size).OrderAsc("id").Scan(&list); err != nil {
		return nil, 0, gerror.Wrap(err, "query roles")
	}
	items := make([]*dto.RoleItem, 0, len(list))
	for i := range list {
		r := &list[i]
		menuIds, err := roleMenuIDs(ctx, r.Id)
		if err != nil {
			return nil, 0, err
		}
		items = append(items, &dto.RoleItem{
			Id: r.Id, Code: r.Code, Name: r.Name, Status: r.Status, MenuIds: menuIds,
			CreatedAt: r.CreatedAt.Layout("2006-01-02 15:04:05"),
		})
	}
	return items, total, nil
}

func (s *roleManage) Create(ctx context.Context, in dto.RoleCreateInput) (uint64, error) {
	count, err := dao.AdminRole.Ctx(ctx).Where(do.AdminRole{Code: in.Code}).Count()
	if err != nil {
		return 0, gerror.Wrap(err, "check role code")
	}
	if count > 0 {
		return 0, response.Error(consts.CodeInvalidParam, "role code already exists")
	}
	id, err := dao.AdminRole.Ctx(ctx).Data(do.AdminRole{Code: in.Code, Name: in.Name, Status: in.Status}).InsertAndGetId()
	if err != nil {
		return 0, gerror.Wrap(err, "insert role")
	}
	if err = bindRoleMenus(ctx, uint64(id), in.MenuIds); err != nil {
		return 0, err
	}
	return uint64(id), nil
}

func (s *roleManage) Update(ctx context.Context, in dto.RoleUpdateInput) error {
	if _, err := dao.AdminRole.Ctx(ctx).Where(do.AdminRole{Id: in.Id}).Data(do.AdminRole{Name: in.Name, Status: in.Status}).Update(); err != nil {
		return gerror.Wrap(err, "update role")
	}
	return bindRoleMenus(ctx, in.Id, in.MenuIds)
}

func (s *roleManage) Delete(ctx context.Context, id uint64) error {
	if _, err := dao.AdminRole.Ctx(ctx).Where(do.AdminRole{Id: id}).Delete(); err != nil {
		return gerror.Wrap(err, "delete role")
	}
	if _, err := dao.AdminRoleMenu.Ctx(ctx).Unscoped().Where(do.AdminRoleMenu{RoleId: id}).Delete(); err != nil {
		return gerror.Wrap(err, "delete role menu bindings")
	}
	if _, err := dao.AdminUserRole.Ctx(ctx).Unscoped().Where(do.AdminUserRole{RoleId: id}).Delete(); err != nil {
		return gerror.Wrap(err, "delete user role bindings")
	}
	return nil
}

func roleMenuIDs(ctx context.Context, roleID uint64) ([]uint64, error) {
	var rels []entity.AdminRoleMenu
	if err := dao.AdminRoleMenu.Ctx(ctx).Where(do.AdminRoleMenu{RoleId: roleID}).Scan(&rels); err != nil {
		return nil, gerror.Wrap(err, "query role menus")
	}
	ids := make([]uint64, 0, len(rels))
	for _, r := range rels {
		ids = append(ids, r.MenuId)
	}
	return ids, nil
}

// bindRoleMenus 全量重绑角色-菜单关系。
func bindRoleMenus(ctx context.Context, roleID uint64, menuIds []uint64) error {
	if _, err := dao.AdminRoleMenu.Ctx(ctx).Unscoped().Where(do.AdminRoleMenu{RoleId: roleID}).Delete(); err != nil {
		return gerror.Wrap(err, "clear role menus")
	}
	for _, mid := range menuIds {
		if _, err := dao.AdminRoleMenu.Ctx(ctx).Data(do.AdminRoleMenu{RoleId: roleID, MenuId: mid}).Insert(); err != nil {
			return gerror.Wrap(err, "bind role menu")
		}
	}
	return nil
}

// ---------------------- Menu manage ----------------------

func (s *menuManage) Tree(ctx context.Context) ([]*dto.MenuNode, error) {
	var list []entity.AdminMenu
	if err := dao.AdminMenu.Ctx(ctx).OrderAsc("sort").Scan(&list); err != nil {
		return nil, gerror.Wrap(err, "query menus")
	}
	byID := make(map[uint64]*dto.MenuNode, len(list))
	for i := range list {
		m := &list[i]
		byID[m.Id] = &dto.MenuNode{
			Id: m.Id, ParentId: m.ParentId, Name: m.Name, Icon: m.Icon, Type: m.Type,
			Path: m.Path, Component: m.Component, Permission: m.Permission,
			Sort: m.Sort, Status: m.Status, Hidden: m.Hidden,
		}
	}
	var roots []*dto.MenuNode
	for i := range list {
		m := &list[i]
		node := byID[m.Id]
		if m.ParentId == 0 {
			roots = append(roots, node)
		} else if p, ok := byID[m.ParentId]; ok {
			p.Children = append(p.Children, node)
		}
	}
	sort.Slice(roots, func(i, j int) bool { return roots[i].Sort < roots[j].Sort })
	for _, r := range roots {
		sortMenuChildren(r)
	}
	return roots, nil
}

func sortMenuChildren(n *dto.MenuNode) {
	sort.Slice(n.Children, func(i, j int) bool { return n.Children[i].Sort < n.Children[j].Sort })
	for _, c := range n.Children {
		sortMenuChildren(c)
	}
}

func (s *menuManage) Create(ctx context.Context, in dto.MenuCreateInput) (uint64, error) {
	count, err := dao.AdminMenu.Ctx(ctx).Where(do.AdminMenu{Permission: in.Permission}).Count()
	if err != nil {
		return 0, gerror.Wrap(err, "check menu permission")
	}
	if count > 0 {
		return 0, response.Error(consts.CodeInvalidParam, "permission already exists")
	}
	id, err := dao.AdminMenu.Ctx(ctx).Data(do.AdminMenu{
		ParentId: in.ParentId, Name: in.Name, Icon: in.Icon, Type: in.Type, Path: in.Path,
		Component: in.Component, Permission: in.Permission, Sort: in.Sort, Status: in.Status, Hidden: in.Hidden,
	}).InsertAndGetId()
	if err != nil {
		return 0, gerror.Wrap(err, "insert menu")
	}
	return uint64(id), nil
}

func (s *menuManage) Update(ctx context.Context, in dto.MenuUpdateInput) error {
	count, err := dao.AdminMenu.Ctx(ctx).Where("permission = ? AND id != ?", in.Permission, in.Id).Count()
	if err != nil {
		return gerror.Wrap(err, "check menu permission")
	}
	if count > 0 {
		return response.Error(consts.CodeInvalidParam, "permission already exists")
	}
	_, err = dao.AdminMenu.Ctx(ctx).Where(do.AdminMenu{Id: in.Id}).Data(do.AdminMenu{
		ParentId: in.ParentId, Name: in.Name, Icon: in.Icon, Type: in.Type, Path: in.Path,
		Component: in.Component, Permission: in.Permission, Sort: in.Sort, Status: in.Status, Hidden: in.Hidden,
	}).Update()
	if err != nil {
		return gerror.Wrap(err, "update menu")
	}
	return nil
}

func (s *menuManage) Delete(ctx context.Context, id uint64) error {
	// 删除前检查是否存在子节点。
	cnt, err := dao.AdminMenu.Ctx(ctx).Where(do.AdminMenu{ParentId: id}).Count()
	if err != nil {
		return gerror.Wrap(err, "check menu children")
	}
	if cnt > 0 {
		return response.Error(consts.CodeInvalidParam, "delete children first")
	}
	if _, err = dao.AdminMenu.Ctx(ctx).Where(do.AdminMenu{Id: id}).Delete(); err != nil {
		return gerror.Wrap(err, "delete menu")
	}
	if _, err = dao.AdminRoleMenu.Ctx(ctx).Unscoped().Where(do.AdminRoleMenu{MenuId: id}).Delete(); err != nil {
		return gerror.Wrap(err, "delete role menu bindings")
	}
	return nil
}