From 5fc0d642ac38742f5eaddd3a4c6916fe23dfb563 Mon Sep 17 00:00:00 2001
From: Naveen <172697+naveensrinivasan@users.noreply.github.com>
Date: Fri, 29 Mar 2024 13:11:13 -0500
Subject: [PATCH] feat: add MergePathAndValueIntoMap (#49)

## Description

- included a helper for generating a nested map.

## Related Issue
https://github.com/defenseunicorns/zarf/pull/2403#discussion_r1543576325

---------

Signed-off-by: naveensrinivasan <172697+naveensrinivasan@users.noreply.github.com>
Co-authored-by: Lucas Rodriguez <lucas.rodriguez@defenseunicorns.com>
Co-authored-by: Lucas Rodriguez <lucas.rodriguez9616@gmail.com>
---
 helpers/misc.go      | 26 +++++++++++++
 helpers/misc_test.go | 87 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 113 insertions(+)

diff --git a/helpers/misc.go b/helpers/misc.go
index 16a02e91..446f1d90 100644
--- a/helpers/misc.go
+++ b/helpers/misc.go
@@ -8,6 +8,7 @@ import (
 	"math"
 	"reflect"
 	"regexp"
+	"strings"
 	"time"
 )
 
@@ -146,3 +147,28 @@ func MergeNonZero[T any](original T, overrides T) T {
 	}
 	return originalValue.Elem().Interface().(T)
 }
+
+// MergePathAndValueIntoMap takes a path in dot notation as a string and a value (also as a string for simplicity),
+// then merges this into the provided map. The value can be any type.
+func MergePathAndValueIntoMap(m map[string]any, path string, value any) error {
+	pathParts := strings.Split(path, ".")
+	current := m
+	for i, part := range pathParts {
+		if i == len(pathParts)-1 {
+			// Set the value at the last key in the path.
+			current[part] = value
+		} else {
+			if _, exists := current[part]; !exists {
+				// If the part does not exist, create a new map for it.
+				current[part] = make(map[string]any)
+			}
+
+			nextMap, ok := current[part].(map[string]any)
+			if !ok {
+				return fmt.Errorf("conflict at %q, expected map but got %T", strings.Join(pathParts[:i+1], "."), current[part])
+			}
+			current = nextMap
+		}
+	}
+	return nil
+}
diff --git a/helpers/misc_test.go b/helpers/misc_test.go
index 44019ae8..0be62db8 100644
--- a/helpers/misc_test.go
+++ b/helpers/misc_test.go
@@ -5,6 +5,7 @@ package helpers
 
 import (
 	"errors"
+	"reflect"
 	"strings"
 	"testing"
 
@@ -199,3 +200,89 @@ func (suite *TestMiscSuite) TestBoolPtr() {
 func TestMisc(t *testing.T) {
 	suite.Run(t, new(TestMiscSuite))
 }
+
+func (suite *TestMiscSuite) TestMergePathAndValueIntoMap() {
+	type args struct {
+		m     map[string]interface{}
+		path  string
+		value interface{}
+	}
+	tests := []struct {
+		name    string
+		args    args
+		wantErr bool
+		want    map[string]any
+	}{
+		{
+			name:    "nested map creation",
+			args:    args{m: make(map[string]interface{}), path: "a.b.c", value: "hello"},
+			wantErr: false,
+			want: map[string]any{
+				"a": map[string]any{
+					"b": map[string]any{
+						"c": "hello",
+					},
+				},
+			},
+		},
+		{
+			name: "overwrite existing value",
+			args: args{m: map[string]interface{}{"a": map[string]any{"b": map[string]any{"c": "initial"}}},
+				path: "a.b.c", value: "updated"},
+			wantErr: false,
+			want: map[string]any{
+				"a": map[string]any{
+					"b": map[string]any{
+						"c": "updated",
+					},
+				},
+			},
+		},
+		{
+			name:    "deeply nested map creation",
+			args:    args{m: make(map[string]interface{}), path: "a.b.c.d.e.f", value: 42},
+			wantErr: false,
+			want: map[string]any{
+				"a": map[string]any{
+					"b": map[string]any{
+						"c": map[string]any{
+							"d": map[string]any{
+								"e": map[string]any{
+									"f": 42,
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+		{
+			name:    "empty path",
+			args:    args{m: make(map[string]interface{}), path: "", value: "root level"},
+			wantErr: false,
+			want: map[string]any{
+				"": "root level",
+			},
+		},
+		{
+			name:    "root level value",
+			args:    args{m: make(map[string]interface{}), path: "root", value: "root value"},
+			wantErr: false,
+			want: map[string]any{
+				"root": "root value",
+			},
+		},
+	}
+	for _, tt := range tests {
+		suite.Run(tt.name, func() {
+			err := MergePathAndValueIntoMap(tt.args.m, tt.args.path, tt.args.value)
+			if tt.wantErr {
+				suite.Error(err, "Expected an error")
+			} else {
+				suite.NoError(err, "Expected no error")
+			}
+
+			suite.True(reflect.DeepEqual(tt.args.m, tt.want), "Map structure mismatch: got %v, want %v", tt.args.m, tt.want)
+		})
+	}
+}