import Spectre
@testable import Stencil


func testExpressions() {
  describe("Expression") {
    let parser = TokenParser(tokens: [], environment: Environment())

    $0.describe("VariableExpression") {
      let expression = VariableExpression(variable: Variable("value"))

      $0.it("evaluates to true when value is not nil") {
        let context = Context(dictionary: ["value": "known"])
        try expect(try expression.evaluate(context: context)).to.beTrue()
      }

      $0.it("evaluates to false when value is unset") {
        let context = Context()
        try expect(try expression.evaluate(context: context)).to.beFalse()
      }

      $0.it("evaluates to true when array variable is not empty") {
        let items: [[String: Any]] = [["key":"key1","value":42],["key":"key2","value":1337]]
        let context = Context(dictionary: ["value": [items]])
        try expect(try expression.evaluate(context: context)).to.beTrue()
      }

      $0.it("evaluates to false when array value is empty") {
        let emptyItems = [[String: Any]]()
        let context = Context(dictionary: ["value": emptyItems])
        try expect(try expression.evaluate(context: context)).to.beFalse()
      }

      $0.it("evaluates to false when dictionary value is empty") {
        let emptyItems = [String:Any]()
        let context = Context(dictionary: ["value": emptyItems])
        try expect(try expression.evaluate(context: context)).to.beFalse()
      }

      $0.it("evaluates to false when Array<Any> value is empty") {
        let context = Context(dictionary: ["value": ([] as [Any])])
        try expect(try expression.evaluate(context: context)).to.beFalse()
      }

      $0.it("evaluates to true when integer value is above 0") {
        let context = Context(dictionary: ["value": 1])
        try expect(try expression.evaluate(context: context)).to.beTrue()
      }

      $0.it("evaluates to true with string") {
        let context = Context(dictionary: ["value": "test"])
        try expect(try expression.evaluate(context: context)).to.beTrue()
      }

      $0.it("evaluates to false when empty string") {
        let context = Context(dictionary: ["value": ""])
        try expect(try expression.evaluate(context: context)).to.beFalse()
      }

      $0.it("evaluates to false when integer value is below 0 or below") {
        let context = Context(dictionary: ["value": 0])
        try expect(try expression.evaluate(context: context)).to.beFalse()

        let negativeContext = Context(dictionary: ["value": 0])
        try expect(try expression.evaluate(context: negativeContext)).to.beFalse()
      }

      $0.it("evaluates to true when float value is above 0") {
        let context = Context(dictionary: ["value": Float(0.5)])
        try expect(try expression.evaluate(context: context)).to.beTrue()
      }

      $0.it("evaluates to false when float is 0 or below") {
        let context = Context(dictionary: ["value": Float(0)])
        try expect(try expression.evaluate(context: context)).to.beFalse()
      }

      $0.it("evaluates to true when double value is above 0") {
        let context = Context(dictionary: ["value": Double(0.5)])
        try expect(try expression.evaluate(context: context)).to.beTrue()
      }

      $0.it("evaluates to false when double is 0 or below") {
        let context = Context(dictionary: ["value": Double(0)])
        try expect(try expression.evaluate(context: context)).to.beFalse()
      }

      $0.it("evaluates to false when uint is 0") {
        let context = Context(dictionary: ["value": UInt(0)])
        try expect(try expression.evaluate(context: context)).to.beFalse()
      }
    }

    $0.describe("NotExpression") {
      $0.it("returns truthy for positive expressions") {
        let expression = NotExpression(expression: StaticExpression(value: true))
        try expect(expression.evaluate(context: Context())).to.beFalse()
      }

      $0.it("returns falsy for negative expressions") {
        let expression = NotExpression(expression: StaticExpression(value: false))
        try expect(expression.evaluate(context: Context())).to.beTrue()
      }
    }

    $0.describe("expression parsing") {
      $0.it("can parse a variable expression") {
        let expression = try parser.compileExpression(components: ["value"])
        try expect(expression.evaluate(context: Context())).to.beFalse()
        try expect(expression.evaluate(context: Context(dictionary: ["value": true]))).to.beTrue()
      }

      $0.it("can parse a not expression") {
        let expression = try parser.compileExpression(components: ["not", "value"])
        try expect(expression.evaluate(context: Context())).to.beTrue()
        try expect(expression.evaluate(context: Context(dictionary: ["value": true]))).to.beFalse()
      }

      $0.describe("and expression") {
        let expression = try! parser.compileExpression(components: ["lhs", "and", "rhs"])

        $0.it("evaluates to false with lhs false") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": false, "rhs": true]))).to.beFalse()
        }

        $0.it("evaluates to false with rhs false") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": true, "rhs": false]))).to.beFalse()
        }

        $0.it("evaluates to false with lhs and rhs false") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": false, "rhs": false]))).to.beFalse()
        }

        $0.it("evaluates to true with lhs and rhs true") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": true, "rhs": true]))).to.beTrue()
        }
      }

      $0.describe("or expression") {
        let expression = try! parser.compileExpression(components: ["lhs", "or", "rhs"])

        $0.it("evaluates to true with lhs true") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": true, "rhs": false]))).to.beTrue()
        }

        $0.it("evaluates to true with rhs true") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": false, "rhs": true]))).to.beTrue()
        }

        $0.it("evaluates to true with lhs and rhs true") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": true, "rhs": true]))).to.beTrue()
        }

        $0.it("evaluates to false with lhs and rhs false") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": false, "rhs": false]))).to.beFalse()
        }
      }

      $0.describe("equality expression") {
        let expression = try! parser.compileExpression(components: ["lhs", "==", "rhs"])

        $0.it("evaluates to true with equal lhs/rhs") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": "a", "rhs": "a"]))).to.beTrue()
        }

        $0.it("evaluates to false with non equal lhs/rhs") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": "a", "rhs": "b"]))).to.beFalse()
        }

        $0.it("evaluates to true with nils") {
          try expect(expression.evaluate(context: Context(dictionary: [:]))).to.beTrue()
        }

        $0.it("evaluates to true with numbers") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": 1, "rhs": 1.0]))).to.beTrue()
        }

        $0.it("evaluates to false with non equal numbers") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": 1, "rhs": 1.1]))).to.beFalse()
        }

        $0.it("evaluates to true with booleans") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": true, "rhs": true]))).to.beTrue()
        }

        $0.it("evaluates to false with falsy booleans") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": true, "rhs": false]))).to.beFalse()
        }

        $0.it("evaluates to false with different types") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": true, "rhs": 1]))).to.beFalse()
        }
      }

      $0.describe("inequality expression") {
        let expression = try! parser.compileExpression(components: ["lhs", "!=", "rhs"])

        $0.it("evaluates to true with inequal lhs/rhs") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": "a", "rhs": "b"]))).to.beTrue()
        }

        $0.it("evaluates to false with equal lhs/rhs") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": "b", "rhs": "b"]))).to.beFalse()
        }
      }

      $0.describe("more than expression") {
        let expression = try! parser.compileExpression(components: ["lhs", ">", "rhs"])

        $0.it("evaluates to true with lhs > rhs") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": 5.0, "rhs": 4]))).to.beTrue()
        }

        $0.it("evaluates to false with lhs == rhs") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": 5.0, "rhs": 5.0]))).to.beFalse()
        }
      }

      $0.describe("more than equal expression") {
        let expression = try! parser.compileExpression(components: ["lhs", ">=", "rhs"])

        $0.it("evaluates to true with lhs == rhs") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": 5.0, "rhs": 5]))).to.beTrue()
        }

        $0.it("evaluates to false with lhs < rhs") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": 5.0, "rhs": 5.1]))).to.beFalse()
        }
      }

      $0.describe("less than expression") {
        let expression = try! parser.compileExpression(components: ["lhs", "<", "rhs"])

        $0.it("evaluates to true with lhs < rhs") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": 4, "rhs": 4.5]))).to.beTrue()
        }

        $0.it("evaluates to false with lhs == rhs") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": 5.0, "rhs": 5.0]))).to.beFalse()
        }
      }

      $0.describe("less than equal expression") {
        let expression = try! parser.compileExpression(components: ["lhs", "<=", "rhs"])

        $0.it("evaluates to true with lhs == rhs") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": 5.0, "rhs": 5]))).to.beTrue()
        }

        $0.it("evaluates to false with lhs > rhs") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": 5.1, "rhs": 5.0]))).to.beFalse()
        }
      }

      $0.describe("multiple expression") {
        let expression = try! parser.compileExpression(components: ["one", "or", "two", "and", "not", "three"])

        $0.it("evaluates to true with one") {
          try expect(expression.evaluate(context: Context(dictionary: ["one": true]))).to.beTrue()
        }

        $0.it("evaluates to true with one and three") {
          try expect(expression.evaluate(context: Context(dictionary: ["one": true, "three": true]))).to.beTrue()
        }

        $0.it("evaluates to true with two") {
          try expect(expression.evaluate(context: Context(dictionary: ["two": true]))).to.beTrue()
        }

        $0.it("evaluates to false with two and three") {
          try expect(expression.evaluate(context: Context(dictionary: ["two": true, "three": true]))).to.beFalse()
        }

        $0.it("evaluates to false with two and three") {
          try expect(expression.evaluate(context: Context(dictionary: ["two": true, "three": true]))).to.beFalse()
        }

        $0.it("evaluates to false with nothing") {
          try expect(expression.evaluate(context: Context())).to.beFalse()
        }
      }
      
      $0.describe("in expression") {
        let expression = try! parser.compileExpression(components: ["lhs", "in", "rhs"])
        
        $0.it("evaluates to true when rhs contains lhs") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": 1, "rhs": [1, 2, 3]]))).to.beTrue()
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": "a", "rhs": ["a", "b", "c"]]))).to.beTrue()
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": "a", "rhs": "abc"]))).to.beTrue()
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": 1, "rhs": 1...3]))).to.beTrue()
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": 1, "rhs": 1..<3]))).to.beTrue()
        }
        
        $0.it("evaluates to false when rhs does not contain lhs") {
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": 1, "rhs": [2, 3, 4]]))).to.beFalse()
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": "a", "rhs": ["b", "c", "d"]]))).to.beFalse()
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": "a", "rhs": "bcd"]))).to.beFalse()
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": 4, "rhs": 1...3]))).to.beFalse()
          try expect(expression.evaluate(context: Context(dictionary: ["lhs": 3, "rhs": 1..<3]))).to.beFalse()
        }
      }
    }
  }
}