feat(api): add model delete, pagination, and cors config

internal/api/list_query.go

@@ -0,0 +1,88 @@
+package api
+
+import (
+	"strconv"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+	"gorm.io/gorm"
+)
+
+type listQuery struct {
+	Page    int
+	Limit   int
+	Offset  int
+	Search  string
+	Enabled bool
+}
+
+func parseListQuery(c *gin.Context) listQuery {
+	var q listQuery
+	if c == nil {
+		return q
+	}
+	if raw := strings.TrimSpace(c.Query("search")); raw != "" {
+		q.Search = raw
+		q.Enabled = true
+	}
+	if raw := strings.TrimSpace(c.Query("page")); raw != "" {
+		if v, err := strconv.Atoi(raw); err == nil && v > 0 {
+			q.Page = v
+		}
+		q.Enabled = true
+	}
+	if raw := strings.TrimSpace(c.Query("limit")); raw != "" {
+		if v, err := strconv.Atoi(raw); err == nil && v > 0 {
+			q.Limit = v
+		}
+		q.Enabled = true
+	}
+	if q.Enabled {
+		if q.Limit <= 0 {
+			q.Limit = 50
+		}
+		if q.Limit > 200 {
+			q.Limit = 200
+		}
+		if q.Page <= 0 {
+			q.Page = 1
+		}
+		q.Offset = (q.Page - 1) * q.Limit
+	}
+	return q
+}
+
+func applyListSearch(q *gorm.DB, search string, fields ...string) *gorm.DB {
+	if q == nil {
+		return q
+	}
+	search = strings.TrimSpace(search)
+	if search == "" || len(fields) == 0 {
+		return q
+	}
+	pattern := "%" + strings.ToLower(search) + "%"
+	clauses := make([]string, 0, len(fields))
+	args := make([]any, 0, len(fields))
+	for _, field := range fields {
+		field = strings.TrimSpace(field)
+		if field == "" {
+			continue
+		}
+		clauses = append(clauses, "LOWER("+field+") LIKE ?")
+		args = append(args, pattern)
+	}
+	if len(clauses) == 0 {
+		return q
+	}
+	return q.Where(strings.Join(clauses, " OR "), args...)
+}
+
+func applyListPagination(q *gorm.DB, query listQuery) *gorm.DB {
+	if q == nil {
+		return q
+	}
+	if !query.Enabled {
+		return q
+	}
+	return q.Limit(query.Limit).Offset(query.Offset)
+}