/// <summary>
/// Returns a <see cref="FilterNegation"/> containing of the inner expression
/// </summary>
public static FilterNegation Make(FilterExpression inner)
{
return(new FilterNegation {
Inner = inner
});
}
/// <summary>
/// Turns a filter expression into an SQL WHERE clause (without the WHERE keyword), adds all required parameters into the <see cref="SqlStatementParameters"/>
/// </summary>
public static string FilterToSql(FilterExpression e, Func <Type, string> sources, SqlStatementParameters ps, JoinTree joinTree, int userId, DateTime?userToday)
{
if (e == null)
{
return(null);
}
// This inner function just relieves us of having to pass all the above parameters each time, they just become part of its closure
string FilterToSqlInner(FilterExpression exp)
{
if (exp is FilterConjunction conExp)
{
return($"({FilterToSqlInner(conExp.Left)}) AND ({FilterToSqlInner(conExp.Right)})");
}
if (exp is FilterDisjunction disExp)
{
return($"({FilterToSqlInner(disExp.Left)}) OR ({FilterToSqlInner(disExp.Right)})");
}
if (exp is FilterNegation notExp)
{
return($"NOT ({FilterToSqlInner(notExp.Inner)})");
}
if (exp is FilterAtom atom)
{
// (A) Prepare the symbol corresponding to the path, e.g. P1
var join = joinTree[atom.Path];
if (join == null)
{
// Developer mistake
throw new InvalidOperationException($"The path '{string.Join('/', atom.Path)}' was not found in the joinTree");
}
var symbol = join.Symbol;
// (B) Determine the type of the property and its value
var propName = atom.Property;
var prop = join.Type.GetProperty(propName);
if (prop == null)
{
// Developer mistake
throw new InvalidOperationException($"Could not find property {propName} on type {join.Type}");
}
// The type of the first operand
var propType = Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType;
if (!string.IsNullOrWhiteSpace(atom.Modifier))
{
// So far all modifiers are only applicable for date properties
if (propType != typeof(DateTime) && propType != typeof(DateTimeOffset))
{
// Developer mistake
throw new InvalidOperationException($"The modifier {atom.Modifier} is not valid for property {propName} since it is not of type DateTime or DateTimeOffset");
}
// So far all modifiers are date modifiers that return INT
propType = typeof(int);
}
// The expected type of the second operand (different in the case of hierarchyId)
var expectedValueType = propType;
if (expectedValueType == typeof(HierarchyId))
{
var idType = join.Type.GetProperty("Id")?.PropertyType;
if (idType == null)
{
// Programmer mistake
throw new InvalidOperationException($"Type {join.Type} is a tree structure but has no Id property");
}
expectedValueType = Nullable.GetUnderlyingType(idType) ?? idType;
}
// (C) Prepare the value (e.g. "'Huntington Rd.'")
var valueString = atom.Value;
object value;
bool isNull = false;
switch (valueString?.ToLower())
{
// This checks all built-in values
case "null":
value = null;
isNull = true;
break;
case "me":
value = userId;
break;
// Relative DateTime values
case "startofyear":
EnsureNullFunction(atom);
EnsureTypeDateTime(atom, propName, propType);
value = StartOfYear(userToday);
break;
case "endofyear":
EnsureNullFunction(atom);
EnsureTypeDateTime(atom, propName, propType);
value = StartOfYear(userToday).AddYears(1);
break;
case "startofquarter":
EnsureNullFunction(atom);
EnsureTypeDateTime(atom, propName, propType);
value = StartOfQuarter(userToday);
break;
case "endofquarter":
EnsureNullFunction(atom);
EnsureTypeDateTime(atom, propName, propType);
value = StartOfQuarter(userToday).AddMonths(3);
break;
case "startofmonth":
EnsureNullFunction(atom);
EnsureTypeDateTime(atom, propName, propType);
value = StartOfMonth(userToday);
break;
case "endofmonth":
EnsureNullFunction(atom);
EnsureTypeDateTime(atom, propName, propType);
value = StartOfMonth(userToday).AddMonths(1);
break;
case "today":
EnsureNullFunction(atom);
EnsureTypeDateTime(atom, propName, propType);
value = Today(userToday);
break;
case "endofday":
EnsureNullFunction(atom);
EnsureTypeDateTime(atom, propName, propType);
value = Today(userToday).AddDays(1);
break;
case "now":
EnsureNullFunction(atom);
EnsureTypeDateTimeOffset(atom, propName, propType);
var now = DateTimeOffset.Now;
value = now;
break;
default:
if (expectedValueType == typeof(string) || expectedValueType == typeof(char))
{
if (!valueString.StartsWith("'") || !valueString.EndsWith("'"))
{
// Developer mistake
throw new InvalidOperationException($"Property {propName} is of type String, therefore the value it is compared to must be enclosed in single quotation marks");
}
valueString = valueString[1..^ 1];
}