package db

import "github.com/uptrace/bun"

type PageOpts struct {
	Page    int
	PerPage int
	Order   bun.Order
	OrderBy string
}

type OrderOpts struct {
	Order   bun.Order
	OrderBy string
	Label   string
}

// TotalPages calculates the total number of pages
func (p *PageOpts) TotalPages(total int) int {
	if p.PerPage == 0 {
		return 0
	}
	pages := total / p.PerPage
	if total%p.PerPage > 0 {
		pages++
	}
	return pages
}

// HasPrevPage checks if there is a previous page
func (p *PageOpts) HasPrevPage() bool {
	return p.Page > 1
}

// HasNextPage checks if there is a next page
func (p *PageOpts) HasNextPage(total int) bool {
	return p.Page < p.TotalPages(total)
}

// GetPageRange returns an array of page numbers to display
// maxButtons controls how many page buttons to show
func (p *PageOpts) GetPageRange(total int, maxButtons int) []int {
	totalPages := p.TotalPages(total)
	if totalPages == 0 {
		return []int{}
	}

	// If total pages is less than max buttons, show all pages
	if totalPages <= maxButtons {
		pages := make([]int, totalPages)
		for i := 0; i < totalPages; i++ {
			pages[i] = i + 1
		}
		return pages
	}

	// Calculate range around current page
	halfButtons := maxButtons / 2
	start := p.Page - halfButtons
	end := p.Page + halfButtons

	// Adjust if at beginning
	if start < 1 {
		start = 1
		end = maxButtons
	}

	// Adjust if at end
	if end > totalPages {
		end = totalPages
		start = totalPages - maxButtons + 1
	}

	pages := make([]int, 0, maxButtons)
	for i := start; i <= end; i++ {
		pages = append(pages, i)
	}
	return pages
}

// StartItem returns the number of the first item on the current page
func (p *PageOpts) StartItem() int {
	if p.Page < 1 {
		return 0
	}
	return (p.Page-1)*p.PerPage + 1
}

// EndItem returns the number of the last item on the current page
func (p *PageOpts) EndItem(total int) int {
	end := p.Page * p.PerPage
	if end > total {
		return total
	}
	return end
}