1 // Copyright 2022-present 650 Industries. All rights reserved.
2 
3 // MARK: - Arguments
4 
5 /**
6  Tries to cast a given value to the type that is wrapped by the dynamic type.
7  - Parameters:
8   - value: A value to be cast. If it's a ``JavaScriptValue``, it's first unpacked to the raw value.
9   - type: Something that implements ``AnyDynamicType`` and knows how to cast the argument.
10  - Returns: A new value converted according to the dynamic type.
11  - Throws: Rethrows various exceptions that could be thrown by the dynamic types.
12  */
13 internal func cast(_ value: Any, toType type: AnyDynamicType, appContext: AppContext) throws -> Any {
14   // TODO: Accept JavaScriptValue and JavaScriptObject as argument types.
15   if !(type is DynamicTypedArrayType), let value = value as? JavaScriptValue {
16     return try type.cast(value.getRaw(), appContext: appContext)
17   }
18   return try type.cast(value, appContext: appContext)
19 }
20 
21 /**
22  Tries to cast the given arguments to the types expected by the function.
23  - Parameters:
24    - arguments: An array of arguments to be cast.
25    - function: A function for which to cast the arguments.
26    - appContext: A context of the app.
27  - Returns: An array of arguments after casting. Its size is the same as the input arrays.
28  - Throws: `InvalidArgsNumberException` when the number of arguments is not equal to the actual number
29  of function's arguments (without an owner and promise). Rethrows exceptions thrown by `cast(_:toType:)`.
30  */
31 internal func cast(arguments: [Any], forFunction function: AnyFunction, appContext: AppContext) throws -> [Any] {
32   let requiredArgumentsCount = function.requiredArgumentsCount
33   let argumentTypeOffset = function.takesOwner ? 1 : 0
34 
35   if arguments.count < requiredArgumentsCount || arguments.count > function.argumentsCount {
36     throw InvalidArgsNumberException((
37       received: arguments.count,
38       expected: function.argumentsCount,
39       required: requiredArgumentsCount
40     ))
41   }
42   return try arguments.enumerated().map { index, argument in
43     let argumentType = function.dynamicArgumentTypes[index + argumentTypeOffset]
44 
45     do {
46       return try cast(argument, toType: argumentType, appContext: appContext)
47     } catch {
48       throw ArgumentCastException((index: index, type: argumentType)).causedBy(error)
49     }
50   }
51 }
52 
53 /**
54  Ensures the provided array of arguments matches the number of arguments expected by the function.
55  - If the function takes the owner, it's added to the beginning.
56  - If the array is still too small, missing arguments are very likely to be optional so it puts `nil` in their place.
57  */
58 internal func concat(arguments: [Any], withOwner owner: AnyObject?, forFunction function: AnyFunction, appContext: AppContext) -> [Any] {
59   var result = arguments
60 
61   if function.takesOwner, let owner = try? function.dynamicArgumentTypes.first?.cast(owner, appContext: appContext) {
62     result = [owner] + arguments
63   }
64   if arguments.count < function.argumentsCount {
65     result += Array(repeating: Any?.none as Any, count: function.argumentsCount - arguments.count)
66   }
67   return result
68 }
69 
70 // MARK: - Exceptions
71 
72 internal class InvalidArgsNumberException: GenericException<(received: Int, expected: Int, required: Int)> {
73   override var reason: String {
74     if param.required < param.expected {
75       return "Received \(param.received) arguments, but \(param.expected) was expected and at least \(param.required) is required"
76     } else {
77       return "Received \(param.received) arguments, but \(param.expected) was expected"
78     }
79   }
80 }
81 
82 internal class ArgumentCastException: GenericException<(index: Int, type: AnyDynamicType)> {
83   override var reason: String {
84     "The \(formatOrdinalNumber(param.index + 1)) argument cannot be cast to type \(param.type.description)"
85   }
86 
87   func formatOrdinalNumber(_ number: Int) -> String {
88     let formatter = NumberFormatter()
89     formatter.numberStyle = .ordinal
90     formatter.locale = Locale(identifier: "en_US")
91     return formatter.string(from: NSNumber(value: number)) ?? ""
92   }
93 }
94 
95 private class ModuleUnavailableException: GenericException<String> {
96   override var reason: String {
97     "Module '\(param)' is no longer available"
98   }
99 }
100