// Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information.

namespace Language

open System
open Xunit
open FSharp.Test.Compiler

module InterpolatedStringsTests =

    [<Fact>]
    let ``Regression: Empty Interpolated String properly typechecks with explicit type on binding`` () =
        Fsx """ let a:byte = $"string" """
        |> compile
        |> shouldFail
        |> withSingleDiagnostic (Error 1, Line 1, Col 15, Line 1, Col 24, "This expression was expected to have type" + Environment.NewLine + "    'byte'    " + Environment.NewLine + "but here has type" + Environment.NewLine + "    'string'    ")

    [<Fact>]
    let ``Interpolated String with hole properly typechecks with explicit type on binding`` () =
        Fsx """ let a:byte = $"strin{'g'}" """
        |> compile
        |> shouldFail
        |> withSingleDiagnostic (Error 1, Line 1, Col 15, Line 1, Col 28, "This expression was expected to have type" + Environment.NewLine + "    'byte'    " + Environment.NewLine + "but here has type" + Environment.NewLine + "    'string'    ")

    [<Fact>]
    let ``Interpolated String without holes properly typeckecks with explicit type on binding`` () = 
        Fsx """
let a: obj = $"string"
let b: System.IComparable = $"string"
let c: System.IFormattable = $"string"
        """
        |> compile
        |> shouldSucceed

    [<Fact>]
    let ``Interpolated string literal typed as FormattableString handles double braces correctly`` () =
        Fsx """
let a = $"{{hello}} world" : System.FormattableString
printf $"{a.Format}"
        """
        |> withLangVersion80
        |> compileExeAndRun
        |> shouldSucceed
        |> withStdOutContains "{{hello}} world"

    [<Fact>]
    let ``Interpolated string with 2 leading dollar characters uses double braces for delimiters`` () =
        // let s = $$"""{{42 + 0}} = {41 + 1}"""
        // printfn "%s" s
        Fsx "let s = $$\"\"\"{{42 + 0}} = {41 + 1}\"\"\"\n\
printfn \"%s\" s"
        |> withLangVersion80
        |> compileExeAndRun
        |> shouldSucceed
        |> withStdOutContains "42 = {41 + 1}"

    [<Fact>]
    let ``Too many consecutive opening braces in interpolated string result in an error`` () =
        // $$"""{{{{42 - 0}}"""
        Fsx "$$\"\"\"{{{{42 - 0}}\"\"\""
        |> withLangVersion80
        |> compile
        |> shouldFail
        |> withSingleDiagnostic (Error 1248, Line 1, Col 1, Line 1, Col 10, "The interpolated triple quoted string literal does not start with enough '$' characters to allow this many consecutive opening braces as content.")

    [<Fact>]
    let ``Too many consecutive closing braces in interpolated string result in an error`` () =
        // $$"""{{42 - 0}}}}"""
        Fsx "$$\"\"\"{{42 - 0}}}}\"\"\""
        |> withLangVersion80
        |> compile
        |> shouldFail
        |> withSingleDiagnostic (Error 1249, Line 1, Col 15, Line 1, Col 21, "The interpolated string contains unmatched closing braces.")

    [<Fact>]
    let ``Percent sign characters in interpolated strings`` () =
        Assert.Equal("%", $"%%")
        Assert.Equal("42%", $"{42}%%")
        Assert.Equal("% 42", $"%%%3d{42}")

    [<Fact>]
    let ``Double percent sign characters in triple quote interpolated strings`` () =
        Fsx "printfn \"%s\" $$$\"\"\"%%\"\"\""
        |> withLangVersion80
        |> compileExeAndRun
        |> shouldSucceed
        |> withStdOutContains "%%"

    [<Fact>]
    let ``Percent sign after interpolation hole in triple quote strings`` () =
        Fsx "printfn \"%s\" $$\"\"\"{{42}}%\"\"\""
        |> withLangVersion80
        |> compileExeAndRun
        |> shouldSucceed
        |> withStdOutContains "42%"

    [<Fact>]
    let ``Percent sign before format specifier in triple quote interpolated strings`` () =
        Fsx "printfn \"%s\" $$\"\"\"%%%3d{{42}}\"\"\""
        |> withLangVersion80
        |> compileExeAndRun
        |> shouldSucceed
        |> withStdOutContains "% 42"

    [<Fact>]
    let ``Percent signs separated by format specifier's flags`` () =
        Fsx """
let s = $"...%-%...{0}"
        """
        |> compile
        |> shouldFail
        |> withSingleDiagnostic (Warning 3376, Line 2, Col 9, Line 2, Col 24, "Bad format specifier: '%'")

    [<Fact>]
    let ``Interpolated expression can be offside`` () =
        Fsx """
let a() =
    let b() =
        $"
{1}"
    b()

type Foo () =
    member _.Bar () =
        let x =
            $"
{2}"
        x
        """
        |> compile
        |> shouldSucceed