namespace UnityLauncherPro

{

internal static class JsonParser

{

// finds the index of the closing } matching the opening { at startIndex

internal static int FindMatchingBrace(string json, int startIndex)

{

int depth = 0;

for (int i = startIndex; i < json.Length; i++)

{

if (json[i] == '{') depth++;

else if (json[i] == '}') { depth--; if (depth == 0) return i; }

}

return -1;

}

// extracts a JSON string value for the given key

internal static string GetStringValue(string json, string key)

{

int keyIndex = json.IndexOf("\"" + key + "\":");

if (keyIndex == -1) return null;

int valueStart = json.IndexOf('"', keyIndex + key.Length + 2) + 1;

if (valueStart == 0) return null;

int valueEnd = json.IndexOf('"', valueStart);

if (valueEnd == -1) return null;

return json.Substring(valueStart, valueEnd - valueStart);

}

// extracts a JSON number value for the given key (returned as string for flexibility)

internal static string GetNumberValue(string json, string key)

{

int keyIndex = json.IndexOf("\"" + key + "\":");

if (keyIndex == -1) return null;

int valueStart = keyIndex + key.Length + 3; // skip past "key":

while (valueStart < json.Length && json[valueStart] == ' ') valueStart++;

int valueEnd = valueStart;

while (valueEnd < json.Length && (char.IsDigit(json[valueEnd]) || json[valueEnd] == '-')) valueEnd++;

return valueEnd > valueStart ? json.Substring(valueStart, valueEnd - valueStart) : null;

}

internal static string ExtractJsonString(string json, string key)

{

int keyIndex = json.IndexOf(key + ":");

if (keyIndex == -1) return null;

int valueStart = json.IndexOf("\"", keyIndex + key.Length + 1);

if (valueStart == -1) return null;

int valueEnd = json.IndexOf("\"", valueStart + 1);

if (valueEnd == -1) return null;

return json.Substring(valueStart + 1, valueEnd - valueStart - 1);

}

internal static string ExtractNestedJsonString(string json, string parentKey, string childKey)

{

int parentIndex = json.IndexOf(parentKey + ":");

if (parentIndex == -1) return null;

// Find the object after parentKey

int objectStart = json.IndexOf("{", parentIndex);

if (objectStart == -1) return null;

int objectEnd = JsonParser.FindMatchingBrace(json, objectStart);

if (objectEnd == -1) return null;

string nestedJson = json.Substring(objectStart, objectEnd - objectStart + 1);

return ExtractJsonString(nestedJson, childKey);

}

} // class

} // namespace