squash! api: refactor pagination

api: return Pagination instead of just Total

api/accounts.go

@@ -575,8 +575,8 @@ func (a *API) sendAccountList(ctx *httprouter.HTTPContext, paramPage string) err
 		return ErrIndexerQueryFailed.WithErr(err)
 	}
 	list := &AccountsList{
-		Accounts: accounts,
-		Total:    total,
+		Accounts:   accounts,
+		Pagination: calculatePagination(page, total),
 	}
 	return marshalAndSend(ctx, list)
 }

api/api_types.go

@@ -17,6 +17,15 @@ type CountResult struct {
 	Count uint64 `json:"count" example:"10"`
 }
 
+// Pagination contains all the values needed for the UI to easily organize the returned data
+type Pagination struct {
+	TotalItems   uint64 `json:"total_items"`
+	TotalPages   uint64 `json:"total_pages"`
+	PreviousPage uint64 `json:"previous_page"`
+	CurrentPage  uint64 `json:"current_page"`
+	NextPage     uint64 `json:"next_page"`
+}
+
 type OrganizationSummary struct {
 	OrganizationID types.HexBytes `json:"organizationID"  example:"0x370372b92514d81a0e3efb8eba9d036ae0877653"`
 	ElectionCount  uint64         `json:"electionCount" example:"1"`
@@ -26,7 +35,7 @@ type OrganizationSummary struct {
 // and return an empty object if the list does not contains any result
 type OrganizationsList struct {
 	Organizations []OrganizationSummary `json:"organizations"`
-	Total         uint64                `json:"total"`
+	Pagination    *Pagination           `json:"pagination"`
 }
 
 type ElectionSummary struct {
@@ -45,8 +54,8 @@ type ElectionSummary struct {
 // ElectionsList wraps the elections list to consistently return the list inside an object,
 // and return an empty object if the list does not contains any result
 type ElectionsList struct {
-	Elections []ElectionSummary `json:"elections"`
-	Total     uint64            `json:"total"`
+	Elections  []ElectionSummary `json:"elections"`
+	Pagination *Pagination       `json:"pagination"`
 }
 
 // ElectionResults is the struct used to wrap the results of an election
@@ -246,8 +255,8 @@ type Account struct {
 }
 
 type AccountsList struct {
-	Accounts []indexertypes.Account `json:"accounts"`
-	Total    uint64                 `json:"total"`
+	Accounts   []indexertypes.Account `json:"accounts"`
+	Pagination *Pagination            `json:"pagination"`
 }
 
 type AccountSet struct {

api/chain.go

@@ -312,7 +312,7 @@ func (a *API) sendOrganizationList(ctx *httprouter.HTTPContext,
 	}
 
 	list := &OrganizationsList{
-		Total: total,
+		Pagination: calculatePagination(page, total),
 	}
 	for _, org := range entities {
 		list.Organizations = append(list.Organizations, OrganizationSummary{

api/elections.go

@@ -276,7 +276,7 @@ func (a *API) sendElectionList(ctx *httprouter.HTTPContext, params *ElectionFilt
 	}
 
 	list := &ElectionsList{
-		Total: total,
+		Pagination: calculatePagination(params.Page, total),
 	}
 	for _, eid := range eids {
 		e, err := a.indexer.ProcessInfo(eid)

api/helpers.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"math"
 	"math/big"
 	"strconv"
 	"strings"
@@ -235,3 +236,22 @@ func parseBool(s string) (bool, error) {
 	}
 	return b, nil
 }
+
+func calculatePagination(page int, totalItems uint64) *Pagination {
+	totalp := math.Ceil(float64(totalItems) / ItemsPerPage)
+	prevp := page - 1
+	if prevp < 0 {
+		prevp = 0
+	}
+	nextp := page + 1
+	if nextp > int(totalp) {
+		nextp = int(totalp)
+	}
+	return &Pagination{
+		TotalItems:   totalItems,
+		TotalPages:   uint64(totalp),
+		PreviousPage: uint64(prevp),
+		CurrentPage:  uint64(page),
+		NextPage:     uint64(nextp),
+	}
+}

test/api_test.go

@@ -263,10 +263,10 @@ func TestAPIAccountsList(t *testing.T) {
 	qt.Assert(t, el["1"], qt.DeepEquals, el["p1"])
 
 	// 2 accounts pre-exist: the faucet account, and the burn address
-	qt.Assert(t, el["0"].Total, qt.Equals, uint64(2+20))
-	qt.Assert(t, el["1"].Total, qt.Equals, el["0"].Total)
-	qt.Assert(t, el["p0"].Total, qt.Equals, el["0"].Total)
-	qt.Assert(t, el["p1"].Total, qt.Equals, el["0"].Total)
+	qt.Assert(t, el["0"].Pagination.TotalItems, qt.Equals, uint64(2+20))
+	qt.Assert(t, el["1"].Pagination.TotalItems, qt.Equals, el["0"].Pagination.TotalItems)
+	qt.Assert(t, el["p0"].Pagination.TotalItems, qt.Equals, el["0"].Pagination.TotalItems)
+	qt.Assert(t, el["p1"].Pagination.TotalItems, qt.Equals, el["0"].Pagination.TotalItems)
 
 	for _, item := range el {
 		qt.Assert(t, len(item.Accounts), qt.Equals, api.ItemsPerPage)
@@ -943,10 +943,10 @@ func TestAPIElectionsList(t *testing.T) {
 	qt.Assert(t, el["0"], qt.DeepEquals, el["p0"])
 	qt.Assert(t, el["1"], qt.DeepEquals, el["p1"])
 
-	qt.Assert(t, el["0"].Total, qt.Equals, uint64(20))
-	qt.Assert(t, el["1"].Total, qt.Equals, el["0"].Total)
-	qt.Assert(t, el["p0"].Total, qt.Equals, el["0"].Total)
-	qt.Assert(t, el["p1"].Total, qt.Equals, el["0"].Total)
+	qt.Assert(t, el["0"].Pagination.TotalItems, qt.Equals, uint64(20))
+	qt.Assert(t, el["1"].Pagination.TotalItems, qt.Equals, el["0"].Pagination.TotalItems)
+	qt.Assert(t, el["p0"].Pagination.TotalItems, qt.Equals, el["0"].Pagination.TotalItems)
+	qt.Assert(t, el["p1"].Pagination.TotalItems, qt.Equals, el["0"].Pagination.TotalItems)
 
 	for _, item := range el {
 		qt.Assert(t, len(item.Elections), qt.Equals, api.ItemsPerPage)