//===----------------------------------------------------------*- swift -*-===//
//
// This source file is part of the Swift Argument Parser open source project
//
// Copyright (c) 2023 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
//
//===----------------------------------------------------------------------===//

import XCTest
@testable import ArgumentParser

final class StringTokenizedTests: XCTestCase {}

func _testTokens(_ input: [String], _ expected: [String], file: StaticString = #file, line: UInt = #line) {
  var input: Array = input.reversed()
  let result = readTokens {
    input.popLast()
  }
  XCTAssertEqual(result, expected, file: file, line: line)
}

func _testTokens(_ input: String, _ expected: [String], file: StaticString = #file, line: UInt = #line) {
  _testTokens([input], expected, file: file, line: line)
}

extension StringTokenizedTests {
  func testTokensSimple() throws {
    _testTokens(#""#, [])
    _testTokens(#"     "#, [])
    _testTokens(#"one"#, ["one"])
    _testTokens(#"      one      "#, ["one"])
    _testTokens(#"one two three"#, ["one", "two", "three"])
    _testTokens(#"   one two     three"#, ["one", "two", "three"])
    _testTokens(#"one two     three      "#, ["one", "two", "three"])
    _testTokens(#"one\ two three"#, ["one two", "three"])
    _testTokens(#"one two \  three"#, ["one", "two", " ", "three"])
    _testTokens(#"one \ \ two three\ \ "#, ["one", "  two", "three  "])
  }
  
  func testTokensSingleQuotes() throws {
    _testTokens(#"one two 'three four'"#, ["one", "two", "three four"])
    _testTokens(#"one two 'three    four'"#, ["one", "two", "three    four"])
    _testTokens(#"one two \'three four"#, ["one", "two", #"'three"#, "four"])
    _testTokens(#"one two '\'three four'"#, ["one", "two", #"'three four"#])
    _testTokens(#"one two '\"three four'"#, ["one", "two", #"\"three four"#])
    _testTokens(#"one two 'three  "  four'"#, ["one", "two", #"three  "  four"#])
    _testTokens(#"one two three'  "  'four"#, ["one", "two", #"three  "  four"#])
    _testTokens(#"one two thr'ee  "  fo'ur"#, ["one", "two", #"three  "  four"#])
  }
  
  func testTokensDoubleQuotes() throws {
    _testTokens(#"one two "three four""#, ["one", "two", "three four"])
    _testTokens(#"one two "three    four""#, ["one", "two", "three    four"])
    _testTokens(#"one two \"three four"#, ["one", "two", #""three"#, "four"])
    _testTokens(#"one two "\"three four""#, ["one", "two", #""three four"#])
    _testTokens(#"one two "\'three four""#, ["one", "two", #"\'three four"#])
    _testTokens(#"one two "three  '  four""#, ["one", "two", #"three  '  four"#])
    _testTokens(#"one two three"  '  "four"#, ["one", "two", #"three  '  four"#])
    _testTokens(#"one two thr"ee  '  fo"ur"#, ["one", "two", #"three  '  four"#])
  }
  
  func testTokensEscapes() throws {
    _testTokens(#"one \a three"#, ["one", #"\a"#, "three"])
  }
  
  func testMultipleLines() throws {
    // Stop at line break
    _testTokens([#"one two three"#, #"four"#], ["one", "two", "three"])
    
    // Quoted sections include line breaks
    _testTokens([#"one two 'three"#, #"four'"#], ["one", "two", "three\nfour"])
    _testTokens([#"'one"#, #"two"#, #"three"#, #"four'"#], ["one\ntwo\nthree\nfour"])
    _testTokens([#"'"#, #"one"#, #"two"#, #"three"#, #"four'"#], ["\none\ntwo\nthree\nfour"])
    _testTokens([#"'one"#, #"two"#, #"three"#, #"four"#, #"'"#], ["one\ntwo\nthree\nfour\n"])
    
    // Escaped line breaks continue, but aren't included
    _testTokens([#"one two three\"#, #"four'"#], ["one", "two", "threefour"])
    _testTokens([#"one\"#, #"two\"#, #"three\"#, #"four'"#], ["onetwothreefour"])
    _testTokens(
      [#"\"#, #"one\"#, #"two\"#, #"three\"#, #"four"#, #"\"#, #"\"#],
      ["onetwothreefour"])
       
    // Skip escaped line breaks even in a quoted section
    _testTokens([#"one two 'three\"#, #"four'"#], ["one", "two", "threefour"])
  }

  func testTokenizedEdgeCases() throws {
    // Unterminated quotes
    _testTokens(#"one two "three"#, ["one", "two", "three"])
    _testTokens(#"one two 'three"#, ["one", "two", "three"])
    // Backslash in last position
    _testTokens(#"one two three\"#, ["one", "two", "three"])
  }
}