package model

import (
	"git.beejay.kim/Craft/Api/connection"
	"github.com/samber/lo"
)

//easyjson:json
type PageInfo[T connection.Cursor] struct {
	Total           int     `json:"total"`
	StartCursor     *string `json:"start_cursor,omitempty"`
	EndCursor       *string `json:"end_cursor,omitempty"`
	HasNextPage     bool    `json:"has_next_page"`
	HasPreviousPage bool    `json:"has_previous_page"`
}

func (pi *PageInfo[T]) SetTotal(nodes []T) {
	pi.Total = len(nodes)
	pi.Invalidate(nodes)
}

func (pi *PageInfo[T]) Invalidate(nodes []T) {
	l := len(nodes)
	if l < 1 {
		pi.HasPreviousPage = pi.StartCursor != nil
		pi.HasNextPage = pi.EndCursor != nil
		pi.StartCursor = nil
		pi.EndCursor = nil
	} else {
		if pi.StartCursor != nil {
			pi.HasPreviousPage = !(*pi.StartCursor == nodes[0].Cursor())
		} else {
			pi.HasPreviousPage = false
		}

		if pi.EndCursor != nil {
			pi.HasNextPage = !(*pi.EndCursor == nodes[l-1].Cursor())
		} else {
			pi.HasNextPage = false
		}

		pi.StartCursor = lo.ToPtr(nodes[0].Cursor())
		pi.EndCursor = lo.ToPtr(nodes[l-1].Cursor())
	}
}