package pagination

import (
	"testing"

	"github.com/stretchr/testify/require"
)

func TestDefaultPagination(t *testing.T) {
	p := DefaultPagination()
	require.Equal(t, 1, p.Page)
	require.Equal(t, 20, p.PageSize)
}

func TestPaginationParams_Offset(t *testing.T) {
	tests := []struct {
		name     string
		page     int
		pageSize int
		want     int
	}{
		{"page_1", 1, 20, 0},
		{"page_2", 2, 20, 20},
		{"page_10", 10, 20, 180},
		{"zero_page", 0, 20, 0}, // < 1 defaults to 1
		{"negative_page", -1, 20, 0},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			p := PaginationParams{Page: tt.page, PageSize: tt.pageSize}
			require.Equal(t, tt.want, p.Offset())
		})
	}
}

func TestPaginationParams_Limit(t *testing.T) {
	tests := []struct {
		name     string
		pageSize int
		want     int
	}{
		{"default_20", 20, 20},
		{"valid_50", 50, 50},
		{"max_100", 100, 100},
		{"exceed_max_150", 150, 100}, // capped at 100
		{"zero_size", 0, 20},         // < 1 defaults to 20
		{"negative_size", -5, 20},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			p := PaginationParams{Page: 1, PageSize: tt.pageSize}
			require.Equal(t, tt.want, p.Limit())
		})
	}
}

func TestPaginationResult_Fields(t *testing.T) {
	result := PaginationResult{
		Total:    100,
		Page:     2,
		PageSize: 20,
		Pages:    5,
	}
	require.Equal(t, int64(100), result.Total)
	require.Equal(t, 2, result.Page)
	require.Equal(t, 20, result.PageSize)
	require.Equal(t, 5, result.Pages)
}