// Package todos: todo lists and items with assignment.
package todos

import (
	"context"
	"errors"

	"atlas9.dev/c/core"
	"atlas9.dev/c/core/iam"
)

// List groups items. An item can belong to any number of lists
// within its tenant.
type List struct {
	ID     core.ID
	Tenant core.ID
	Name   string
}

type Item struct {
	ID     core.ID
	Tenant core.ID
	Title  string
	Notes  string
	Status Status
	// Assignee is the user assigned to the item. Empty means unassigned.
	// Assignees must be members of the item's tenant.
	Assignee core.ID
}

type Status string

const (
	StatusOpen       Status = "open"
	StatusInProgress Status = "in_progress"
	StatusDone       Status = "done"
)

func (s Status) Valid() bool {

	switch s {
	case StatusOpen, StatusInProgress, StatusDone:
		return true
	}
	return false
}

var (
	Cap_Todos_CreateList     = iam.NewCap("Todos_CreateList")
	Cap_Todos_UpdateList     = iam.NewCap("Todos_UpdateList")
	Cap_Todos_ReadList       = iam.NewCap("Todos_ReadList")
	Cap_Todos_DeleteList     = iam.NewCap("Todos_DeleteList")
	Cap_Todos_AddToList      = iam.NewCap("Todos_AddToList")
	Cap_Todos_RemoveFromList = iam.NewCap("Todos_RemoveFromList")

	Cap_Todos_CreateItem = iam.NewCap("Todos_CreateItem")
	Cap_Todos_UpdateItem = iam.NewCap("Todos_UpdateItem")
	Cap_Todos_ReadItem   = iam.NewCap("Todos_ReadItem")
	Cap_Todos_DeleteItem = iam.NewCap("Todos_DeleteItem")
)

var ErrAssigneeNotMember = errors.New("assignee is not a member of the tenant")

type Store interface {
	CreateList(ctx context.Context, list *List) error
	UpdateList(ctx context.Context, list *List) error
	GetList(ctx context.Context, tenant core.ID, id core.ID, out *List) error
	ListLists(ctx context.Context, tenant core.ID, page core.PageReq, out *core.Page[List]) error
	DeleteList(ctx context.Context, tenant core.ID, id core.ID) error

	AddToList(ctx context.Context, tenant core.ID, list core.ID, item core.ID) error
	RemoveFromList(ctx context.Context, tenant core.ID, list core.ID, item core.ID) error

	CreateItem(ctx context.Context, item *Item) error
	UpdateItem(ctx context.Context, item *Item) error
	GetItem(ctx context.Context, tenant core.ID, id core.ID, out *Item) error
	// ListItems lists items in the tenant. When list is non-empty, only
	// items belonging to that list are returned.
	ListItems(ctx context.Context, tenant core.ID, list core.ID, page core.PageReq, out *core.Page[Item]) error
	DeleteItem(ctx context.Context, tenant core.ID, id core.ID) error
}