From 4a33986b6a94c5dce187f8a6a90492a83b0822cc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mike=20Schw=C3=B6rer?= <pubgit@mikescher.com>
Date: Mon, 11 Mar 2024 16:40:41 +0100
Subject: [PATCH] v0.0.407 sq.Iterate

---
 goextVersion.go |  4 +--
 sq/filter.go    |  7 +++++
 sq/list.go      | 48 +++++++++++++++++++++++++++++++
 sq/paginate.go  |  8 ++++++
 sq/scanner.go   | 76 +++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 141 insertions(+), 2 deletions(-)
 create mode 100644 sq/list.go

diff --git a/goextVersion.go b/goextVersion.go
index 45a97df..62cd23c 100644
--- a/goextVersion.go
+++ b/goextVersion.go
@@ -1,5 +1,5 @@
 package goext
 
-const GoextVersion = "0.0.406"
+const GoextVersion = "0.0.407"
 
-const GoextVersionTimestamp = "2024-03-10T16:44:21+0100"
+const GoextVersionTimestamp = "2024-03-11T16:40:41+0100"
diff --git a/sq/filter.go b/sq/filter.go
index fa6b97c..c486292 100644
--- a/sq/filter.go
+++ b/sq/filter.go
@@ -47,3 +47,10 @@ func NewSimplePaginateFilter(filterClause string, filterParams PP, sort []Filter
 		},
 	}
 }
+
+func NewEmptyPaginateFilter() PaginateFilter {
+	return genericPaginateFilter{
+		sql:  func(params PP) (string, string, []string) { return "1=1", "", nil },
+		sort: func() []FilterSort { return make([]FilterSort, 0) },
+	}
+}
diff --git a/sq/list.go b/sq/list.go
new file mode 100644
index 0000000..affee37
--- /dev/null
+++ b/sq/list.go
@@ -0,0 +1,48 @@
+package sq
+
+import (
+	"context"
+	"fmt"
+	"gogs.mikescher.com/BlackForestBytes/goext/exerr"
+)
+
+func Iterate[TData any](ctx context.Context, q Queryable, table string, filter PaginateFilter, scanMode StructScanMode, scanSec StructScanSafety, page int, limit *int, consumer func(v TData) error) (int, error) {
+	if filter == nil {
+		filter = NewEmptyPaginateFilter()
+	}
+
+	prepParams := PP{}
+
+	sortOrder := filter.Sort()
+	sortCond := ""
+	if len(sortOrder) > 0 {
+		sortCond = "ORDER BY "
+		for i, v := range sortOrder {
+			if i > 0 {
+				sortCond += ", "
+			}
+			sortCond += v.Field + " " + string(v.Direction)
+		}
+	}
+
+	pageCond := ""
+	if limit != nil {
+		pageCond += fmt.Sprintf("LIMIT :%s OFFSET :%s", prepParams.Add(*limit+1), prepParams.Add(*limit*(page-1)))
+	}
+
+	filterCond, joinCond, joinTables := filter.SQL(prepParams)
+
+	selectCond := table + ".*"
+	for _, v := range joinTables {
+		selectCond += ", " + v + ".*"
+	}
+
+	sqlQueryData := "SELECT " + selectCond + " FROM " + table + " " + joinCond + " WHERE ( " + filterCond + " ) " + sortCond + " " + pageCond
+
+	rows, err := q.Query(ctx, sqlQueryData, prepParams)
+	if err != nil {
+		return 0, exerr.Wrap(err, "failed to list paginated entries from DB").Str("table", table).Any("filter", filter).Int("page", page).Any("limit", limit).Build()
+	}
+
+	return IterateAll[TData](ctx, q, rows, scanMode, scanSec, true, consumer)
+}
diff --git a/sq/paginate.go b/sq/paginate.go
index d5dea99..e0fac2f 100644
--- a/sq/paginate.go
+++ b/sq/paginate.go
@@ -9,6 +9,10 @@ import (
 )
 
 func Paginate[TData any](ctx context.Context, q Queryable, table string, filter PaginateFilter, scanMode StructScanMode, scanSec StructScanSafety, page int, limit *int) ([]TData, pag.Pagination, error) {
+	if filter == nil {
+		filter = NewEmptyPaginateFilter()
+	}
+
 	prepParams := PP{}
 
 	sortOrder := filter.Sort()
@@ -90,6 +94,10 @@ func Paginate[TData any](ctx context.Context, q Queryable, table string, filter
 }
 
 func Count(ctx context.Context, q Queryable, table string, filter PaginateFilter) (int, error) {
+	if filter == nil {
+		filter = NewEmptyPaginateFilter()
+	}
+
 	prepParams := PP{}
 
 	filterCond, joinCond, _ := filter.SQL(prepParams)
diff --git a/sq/scanner.go b/sq/scanner.go
index 9ff33ef..7a422ab 100644
--- a/sq/scanner.go
+++ b/sq/scanner.go
@@ -333,3 +333,79 @@ func ScanAll[TData any](ctx context.Context, q Queryable, rows *sqlx.Rows, mode
 	}
 	return res, nil
 }
+
+func IterateAll[TData any](ctx context.Context, q Queryable, rows *sqlx.Rows, mode StructScanMode, sec StructScanSafety, close bool, consumer func(v TData) error) (int, error) {
+	var strscan *StructScanner
+
+	if sec == Safe {
+		strscan = NewStructScanner(rows, false)
+		var data TData
+		err := strscan.Start(&data)
+		if err != nil {
+			return 0, err
+		}
+	} else if sec == Unsafe {
+		strscan = NewStructScanner(rows, true)
+		var data TData
+		err := strscan.Start(&data)
+		if err != nil {
+			return 0, err
+		}
+	} else {
+		return 0, errors.New("unknown value for <sec>")
+	}
+
+	rcount := 0
+
+	for rows.Next() {
+
+		if err := ctx.Err(); err != nil {
+			return rcount, err
+		}
+
+		if mode == SModeFast {
+			var data TData
+			err := strscan.StructScanBase(&data)
+			if err != nil {
+				return rcount, err
+			}
+
+			err = consumer(data)
+			if err != nil {
+				return rcount, exerr.Wrap(err, "").Build()
+			}
+
+			rcount++
+
+		} else if mode == SModeExtended {
+			var data TData
+			err := strscan.StructScanExt(q, &data)
+			if err != nil {
+				return rcount, err
+			}
+
+			err = consumer(data)
+			if err != nil {
+				return rcount, exerr.Wrap(err, "").Build()
+			}
+
+			rcount++
+
+		} else {
+			return rcount, errors.New("unknown value for <mode>")
+		}
+	}
+
+	if close {
+		err := strscan.rows.Close()
+		if err != nil {
+			return rcount, err
+		}
+	}
+
+	if err := rows.Err(); err != nil {
+		return rcount, err
+	}
+
+	return rcount, nil
+}