//===--- Index.swift.gyb - tests for Index types and operations -----------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
// -*- swift -*-
// RUN: rm -rf %t ; mkdir -p %t
// RUN: %S/../../utils/gyb %s -o %t/Index.swift
// RUN: %S/../../utils/line-directive %t/Index.swift -- %target-build-swift %t/Index.swift -o %t/a.out
// RUN: %S/../../utils/line-directive %t/Index.swift -- %target-run %t/a.out
// REQUIRES: executable_test

import StdlibUnittest
import StdlibCollectionUnittest

// Also import modules which are used by StdlibUnittest internally. This
// workaround is needed to link all required libraries in case we compile
// StdlibUnittest with -sil-serialize-all.
import SwiftPrivate
#if _runtime(_ObjC)
import ObjectiveC
#endif

extension Collection {
  func indexAt(offset offset: Int) -> Index {
    return self.index(numericCast(offset), stepsFrom: self.startIndex)
  }
}

struct DistanceToTest {
  let startIndex: Int
  let endIndex: Int
  let expectedDistance: Int
  let loc: SourceLoc

  init(
    startIndex: Int, endIndex: Int, expectedDistance: Int,
    file: String = #file, line: UInt = #line
  ) {
    self.startIndex = startIndex
    self.endIndex = endIndex
    self.expectedDistance = expectedDistance
    self.loc = SourceLoc(file, line, comment: "distance(from:to:) test data")
  }
}

struct AdvanceByTest {
  let startIndex: Int
  let distance: Int
  let limit: Int?
  let expectedIndex: Int
  let loc: SourceLoc
  init(
    startIndex: Int, distance: Int, expectedIndex: Int,
    limit: Int? = nil,
    file: String = #file, line: UInt = #line
  ) {
    self.startIndex = startIndex
    self.distance = distance
    self.expectedIndex = expectedIndex
    self.limit = limit
    self.loc = SourceLoc(file, line, comment: "advance(_:by:) test data")
  }
}

let distanceToTests = [
  DistanceToTest(
    startIndex: 0,
    endIndex: 0,
    expectedDistance: 0
  ),
  DistanceToTest(
    startIndex: 10,
    endIndex: 10,
    expectedDistance: 0
  ),
  DistanceToTest(
    startIndex: 10,
    endIndex: 13,
    expectedDistance: 3
  ),
  DistanceToTest(
    startIndex: 7,
    endIndex: 10,
    expectedDistance: 3
  ),
]

let advancedByTests = [
  AdvanceByTest(
    startIndex: 0,
    distance: 0,
    expectedIndex: 0
  ),
  AdvanceByTest(
    startIndex: 0,
    distance: -1,
    expectedIndex: -1
  ),
  AdvanceByTest(
    startIndex: 0,
    distance: 0,
    expectedIndex: 0,
    limitedBy: 0
  ),
  AdvanceByTest(
    startIndex: 0,
    distance: 0,
    expectedIndex: 0,
    limitedBy: 10
  ),
  AdvanceByTest(
    startIndex: 0,
    distance: 10,
    expectedIndex: 0,
    limitedBy: 0
  ),
  AdvanceByTest(
    startIndex: 0,
    distance: -10,
    expectedIndex: 0,
    limitedBy: 0
  ),
  AdvanceByTest(
    startIndex: 0,
    distance: 10,
    expectedIndex: 10,
    limitedBy: 10
  ),
  AdvanceByTest(
    startIndex: 0,
    distance: 20,
    expectedIndex: 10,
    limitedBy: 10
  ),
  AdvanceByTest(
    startIndex: 10,
    distance: -20,
    expectedIndex: 0,
    limitedBy: 0
  ),
]

var Index = TestSuite("Index")

% from gyb_stdlib_support import collectionForTraversal

% # RandomAccess does not add any new behaviors to Bidirectional
% # so we are left with just 2 traversals for the following tests
% for Traversal in ['Forward', 'Bidirectional']:
%   TraversalCollection = collectionForTraversal(Traversal)

Index.test("${TraversalCollection}/distance(to:)/dispatch") {
  let c = ${TraversalCollection}Log.dispatchTester(Array(0..<10))
  _ = c.distance(from: 0, to: 10)
  expectCustomizable(c, c.log.distance)
}

Index.test("${TraversalCollection}/advance(_:by:)/dispatch") {
  let c = ${TraversalCollection}Log.dispatchTester(Array(0..<10))
  _ = c.index(10, stepsFrom: c.startIndex)
  expectCustomizable(c, c.log.advance)
}

Index.test("${TraversalCollection}/advance(_:by:limit:)/dispatch") {
  let c = ${TraversalCollection}Log.dispatchTester(Array(0..<10))
  _ = c.index(10, stepsFrom: c.startIndex, limitedBy: 5)
  expectCustomizable(c, c.log.advanceLimit)
}

% end

% for Traversal in ['Forward', 'Bidirectional', 'RandomAccess']:
%   CollectionPrefix = collectionForTraversal(Traversal).replace('Collection', '')
%   for Base in ['Minimal', 'Defaulted']:
%     Kind = '{}{}'.format(Base, CollectionPrefix)

Index.test("${Kind}Collection/distance(from:to:)/semantics") {
  let c = ${Kind}Collection(elements: Array(0..<20))
  for test in distanceToTests {
    let d = c.distance(
      from: c.indexAt(offset: test.startIndex),
      to: c.indexAt(offset: test.endIndex))
    expectEqual(test.expectedDistance, d,
      stackTrace: SourceLocStack().with(test.loc))
  }
}

Index.test("${Kind}Collection/advance(_:by: n)/semantics") {
  for test in advancedByTests.filter({$0.limit == nil && $0.distance >= 0}) {
    let c = ${Kind}Collection(elements: Array(0..<10))

    let new = c.advance(c.indexAt(offset: test.startIndex), by: test.distance)
    // Since the `indexAt(offset:)` method performs the same operation
    // (i.e. adavances `c.startIndex` by `test.distance`, it would be
    // silly to compare index values. Luckily the underlying collection
    // contains exactly index offsets.
    expectEqual(test.expectedIndex, c[new],
      stackTrace: SourceLocStack().with(test.loc))
  }
}

%     if Traversal == 'Forward':
Index.test("${Kind}Collection/advance(_:by: -n)/semantics") {
  for test in advancedByTests.filter({$0.limit == nil && $0.distance < 0}) {
    let c = ${Kind}Collection(elements: Array(0..<10))
    expectCrashLater()
    _ = c.advance(c.indexAt(offset: test.startIndex), by: test.distance)
  }
}
%     end

%     if Traversal == 'Forward':
Index.test("${Kind}Collection/advance(by: -n, limit:)/semantics") {
  for test in advancedByTests.filter({$0.limit != nil && $0.distance < 0}) {
    let c = ${Kind}Collection(elements: Array(0..<10))
    let limit = c.indexAt(offset: test.limit.unsafelyUnwrapped)

    expectCrashLater()
    _ = c.advance(c.indexAt(offset: test.startIndex),
      by: test.distance, limitedBy: limit)
  }
}
%     end

Index.test("${Kind}Collection/advance(by: n, limit:)/semantics") {
  for test in advancedByTests.filter({$0.limit != nil && $0.distance >= 0}) {
    let c = ${Kind}Collection(elements: Array(0..<10))
    let limit = c.indexAt(offset: test.limit.unsafelyUnwrapped)

%     if Traversal == 'Forward':

    if test.distance < 0 {
      expectCrashLater()
    }

%     end

    let new = c.advance(c.indexAt(offset: test.startIndex),
      by: test.distance, limitedBy: limit)
    expectEqual(c.indexAt(offset: test.expectedIndex), new,
      stackTrace: SourceLocStack().with(test.loc))
  }
}

// Check that a random access collection doesn't call into O(n) predecessor
// calls when it has a more efficient implementation.

%     if Traversal == 'RandomAccess' and Base == 'Defaulted':

Index.test(
  "${Kind}Collection/advance(_:by:)/avoidsSuccessorAndPredecessor/dispatch"
) {
  for test in advancedByTests.filter({$0.limit == nil && $0.distance >= 0}) {
    let c = ${Kind}Collection(Array(0..<10))

    let i = c.indexAt(offset: test.startIndex)
    let result  = c.index(test.distance, stepsFrom: i)
    expectEqual(0, c.timesSuccessorCalled.value)
    expectEqual(0, c.timesPredecessorCalled.value)
  }
}

Index.test(
  "${Kind}Index/advance(_:by:limit:)/avoidsSuccessorAndPredecessor/dispatch"
).xfail(.custom({ true }, reason: "[swift-3-indexing-model] Implementation missing"))
.code {
  for test in advancedByTests.filter({$0.limit != nil && $0.distance >= 0}) {
    let c = ${Kind}Collection(Array(0..<10))

    let i = c.indexAt(offset: test.startIndex)
    let limit = c.indexAt(offset: test.limit.unsafelyUnwrapped)
    let result  = c.index(test.distance, stepsFrom: i, limitedBy: limit)
    expectEqual(0, c.timesSuccessorCalled.value)
    expectEqual(0, c.timesPredecessorCalled.value)
  }
}

%     end
%   end
% end

runAllTests()