From 19ca22acccade5efead787fa3d204fe49f92ff79 Mon Sep 17 00:00:00 2001
From: xing <fthvgb1>
Date: Sun, 28 Aug 2022 21:27:41 +0800
Subject: [PATCH] pagination

---
 helper/func.go  | 10 +++++++
 main.go         |  4 +--
 models/model.go | 69 +++++++++++++++++++++++++++++++++++++++++++++----
 3 files changed, 76 insertions(+), 7 deletions(-)
 create mode 100644 helper/func.go

diff --git a/helper/func.go b/helper/func.go
new file mode 100644
index 0000000..ba413f1
--- /dev/null
+++ b/helper/func.go
@@ -0,0 +1,10 @@
+package helper
+
+func IsContainInArr[T comparable](a T, arr []T) bool {
+	for _, v := range arr {
+		if a == v {
+			return true
+		}
+	}
+	return false
+}
diff --git a/main.go b/main.go
index d87624f..6ceb730 100644
--- a/main.go
+++ b/main.go
@@ -19,9 +19,9 @@ func init() {
 }
 
 func main() {
-	T, err := models.WpPostsM.FindOneById(3)
+	T, total, err := models.WpPostsM.SimplePagination(models.SqlBuilder{{"post_content", "like", "%哟%"}}, "*", 2, 10, models.SqlBuilder{{"ID", "desc"}})
 	if err != nil {
 		return
 	}
-	fmt.Println(T)
+	fmt.Println(T, total)
 }
diff --git a/models/model.go b/models/model.go
index b73f47b..4893ebd 100644
--- a/models/model.go
+++ b/models/model.go
@@ -3,6 +3,7 @@ package models
 import (
 	"fmt"
 	"github/fthvgb1/wp-go/db"
+	"github/fthvgb1/wp-go/helper"
 	"strings"
 )
 
@@ -14,9 +15,9 @@ type mod interface {
 type model[T mod] struct {
 }
 
-type SimpleWhere [][]string
+type SqlBuilder [][]string
 
-func (w SimpleWhere) parseWhere() (string, []interface{}) {
+func (w SqlBuilder) parseWhere() (string, []interface{}) {
 	var s strings.Builder
 	args := make([]interface{}, 0, len(w))
 	for _, ss := range w {
@@ -31,13 +32,59 @@ func (w SimpleWhere) parseWhere() (string, []interface{}) {
 			s.WriteString(ss[0])
 			s.WriteString("`")
 			s.WriteString(ss[1])
-			s.WriteString("? and ")
+			s.WriteString(" ? and ")
 			args = append(args, ss[2])
 		}
 	}
 	return strings.TrimRight(s.String(), "and "), args
 }
 
+func (w SqlBuilder) parseOrderBy() string {
+	s := strings.Builder{}
+	for _, ss := range w {
+		if len(ss) == 2 && ss[0] != "" && helper.IsContainInArr(ss[1], []string{"asc", "desc"}) {
+			s.WriteString(" `")
+			s.WriteString(ss[0])
+			s.WriteString("` ")
+			s.WriteString(ss[1])
+			s.WriteString(",")
+		}
+	}
+	return strings.TrimRight(s.String(), ",")
+}
+
+func (m model[T]) SimplePagination(where SqlBuilder, fields string, page, pageSize int, order SqlBuilder) (r []T, total int, err error) {
+	var rr T
+	w, args := where.parseWhere()
+	n := struct {
+		N int `db:"n" json:"n"`
+	}{}
+	tpx := "select count(*) n from %s where %s limit 1"
+	sq := fmt.Sprintf(tpx, rr.Table(), w)
+	err = db.Db.Get(&n, sq, args...)
+	if err != nil {
+		return
+	}
+	if n.N == 0 {
+		return
+	}
+	total = n.N
+	offset := 0
+	if page > 1 {
+		offset = (page - 1) * pageSize
+	}
+	if offset >= total {
+		return
+	}
+	tp := "select %s from %s where %s order by %s limit %d,%d"
+	sql := fmt.Sprintf(tp, fields, rr.Table(), w, order.parseOrderBy(), offset, pageSize)
+	err = db.Db.Select(&r, sql, args...)
+	if err != nil {
+		return
+	}
+	return
+}
+
 func (m model[T]) FindOneById(id int) (T, error) {
 	var r T
 	sql := fmt.Sprintf("select * from `%s` where `%s`=?", r.Table(), r.PrimaryKey())
@@ -48,7 +95,7 @@ func (m model[T]) FindOneById(id int) (T, error) {
 	return r, nil
 }
 
-func (m model[T]) FirstOne(where SimpleWhere, fields string) (T, error) {
+func (m model[T]) FirstOne(where SqlBuilder, fields string) (T, error) {
 	var r T
 	w, args := where.parseWhere()
 	tp := "select %s from %s where %s"
@@ -60,7 +107,19 @@ func (m model[T]) FirstOne(where SimpleWhere, fields string) (T, error) {
 	return r, nil
 }
 
-func (m model[T]) FindMany(where SimpleWhere, fields string) ([]T, error) {
+func (m model[T]) LastOne(where SqlBuilder, fields string) (T, error) {
+	var r T
+	w, args := where.parseWhere()
+	tp := "select %s from %s where %s order by %s desc limit 1"
+	sql := fmt.Sprintf(tp, fields, r.Table(), w, r.PrimaryKey())
+	err := db.Db.Get(&r, sql, args...)
+	if err != nil {
+		return r, err
+	}
+	return r, nil
+}
+
+func (m model[T]) FindMany(where SqlBuilder, fields string) ([]T, error) {
 	var r []T
 	var rr T
 	w, args := where.parseWhere()