//===--- Function.swift - Defines the Function class ----------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//

import SILBridging

final public class Function : CustomStringConvertible, HasName {

  public var name: String {
    return SILFunction_getName(bridged).string
  }

  final public var description: String {
    return SILFunction_debugDescription(bridged).takeString()
  }

  public var entryBlock: BasicBlock {
    SILFunction_firstBlock(bridged).block!
  }

  public var blocks : List<BasicBlock> {
    return List(first: SILFunction_firstBlock(bridged).block)
  }

  public var arguments: LazyMapSequence<ArgumentArray, FunctionArgument> {
    entryBlock.arguments.lazy.map { $0 as! FunctionArgument }
  }

  public var numIndirectResultArguments: Int {
    SILFunction_numIndirectResultArguments(bridged)
  }

  public var hasSelfArgument: Bool {
    SILFunction_getSelfArgumentIndex(bridged) >= 0
  }

  public var selfArgumentIndex: Int {
    let selfIdx = SILFunction_getSelfArgumentIndex(bridged)
    assert(selfIdx >= 0)
    return selfIdx
  }
  
  public var argumentTypes: ArgumentTypeArray { ArgumentTypeArray(function: self) }
  public var resultType: Type { SILFunction_getSILResultType(bridged).type }

  public var bridged: BridgedFunction { BridgedFunction(obj: SwiftObject(self)) }
}

public func == (lhs: Function, rhs: Function) -> Bool { lhs === rhs }
public func != (lhs: Function, rhs: Function) -> Bool { lhs !== rhs }

public struct ArgumentTypeArray : RandomAccessCollection, FormattedLikeArray {
  fileprivate let function: Function

  public var startIndex: Int { return 0 }
  public var endIndex: Int { SILFunction_getNumSILArguments(function.bridged) }

  public subscript(_ index: Int) -> Type {
    SILFunction_getSILArgumentType(function.bridged, index).type
  }
}

// Bridging utilities

extension BridgedFunction {
  public var function: Function { obj.getAs(Function.self) }
}

extension OptionalBridgedFunction {
  public var function: Function? { obj.getAs(Function.self) }
}