Files
Print_server/Inspectron.Epson.TemplateEngine/DataBinding/DataContext.cs
2026-02-03 14:27:13 +01:00

124 lines
3.3 KiB
C#

using System.Text.Json;
namespace Inspectron.Epson.TemplateEngine.DataBinding;
public class DataContext
{
private readonly JsonElement _root;
private readonly DataContext? _parent;
private readonly Dictionary<string, JsonElement> _variables = new(StringComparer.OrdinalIgnoreCase);
private readonly Dictionary<string, object> _loopVariables = new(StringComparer.OrdinalIgnoreCase);
public DataContext(JsonElement root)
{
_root = root;
}
private DataContext(JsonElement root, DataContext parent)
{
_root = root;
_parent = parent;
}
public DataContext CreateChildScope()
{
return new DataContext(_root, this);
}
public void SetVariable(string name, JsonElement value)
{
_variables[name] = value;
}
public void SetLoopVariable(string name, object value)
{
_loopVariables[name] = value;
}
public object? GetLoopVariable(string name)
{
if (_loopVariables.TryGetValue(name, out var value))
return value;
return _parent?.GetLoopVariable(name);
}
public JsonElement? Resolve(string expression)
{
if (string.IsNullOrWhiteSpace(expression))
return null;
var parts = expression.Split('.');
var firstPart = parts[0];
// Check local variables first
JsonElement? current = null;
if (_variables.TryGetValue(firstPart, out var varValue))
{
current = varValue;
}
else if (_parent != null)
{
// Walk up scope chain for variables
var ctx = _parent;
while (ctx != null)
{
if (ctx._variables.TryGetValue(firstPart, out var parentVar))
{
current = parentVar;
break;
}
ctx = ctx._parent;
}
}
// If not found in variables, try root
if (current == null)
{
current = GetProperty(_root, firstPart);
}
if (current == null)
return null;
// Navigate remaining parts
for (int i = 1; i < parts.Length; i++)
{
current = GetProperty(current.Value, parts[i]);
if (current == null)
return null;
}
return current;
}
private static JsonElement? GetProperty(JsonElement element, string propertyName)
{
if (element.ValueKind != JsonValueKind.Object)
return null;
// Case-insensitive property lookup
foreach (var prop in element.EnumerateObject())
{
if (string.Equals(prop.Name, propertyName, StringComparison.OrdinalIgnoreCase))
return prop.Value;
}
return null;
}
public static string GetStringValue(JsonElement element)
{
return element.ValueKind switch
{
JsonValueKind.String => element.GetString() ?? "",
JsonValueKind.Number => element.TryGetInt64(out var l) ? l.ToString() : element.GetDouble().ToString(),
JsonValueKind.True => "true",
JsonValueKind.False => "false",
JsonValueKind.Null => "",
JsonValueKind.Undefined => "",
_ => element.GetRawText()
};
}
}