// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.IO;
using System.Linq;
using Microsoft.AspNetCore.Testing;
using Xunit;

namespace Microsoft.AspNetCore.Razor.Language
{
    public class RazorTemplateEngineTest
    {
        [Fact]
        public void GetImports_CanQueryInformationOnNonExistentFileWithoutImports()
        {
            // Arrange
            var project = new TestRazorProject();
            var razorEngine = RazorEngine.Create();
            var templateEngine = new RazorTemplateEngine(razorEngine, project)
            {
                Options =
                {
                    ImportsFileName = "MyImport.cshtml"
                }
            };
            var projectItemToQuery = project.GetItem("/Views/Home/Index.cshtml");

            // Act
            var imports = templateEngine.GetImports(projectItemToQuery);

            // Assert
            Assert.Empty(imports);
        }

        [Fact]
        public void GetImports_CanQueryInformationOnNonExistentFileWithImports()
        {
            // Arrange
            var path = "/Views/Home/MyImport.cshtml";
            var projectItem = new TestRazorProjectItem(path);
            var project = new TestRazorProject(new[] { projectItem });
            var razorEngine = RazorEngine.Create();
            var templateEngine = new RazorTemplateEngine(razorEngine, project)
            {
                Options =
                {
                    ImportsFileName = "MyImport.cshtml"
                }
            };
            var projectItemToQuery = project.GetItem("/Views/Home/Index.cshtml");

            // Act
            var imports = templateEngine.GetImports(projectItemToQuery);

            // Assert
            var import = Assert.Single(imports);
            Assert.Equal(projectItem.FilePath, import.FilePath);
        }

        [Fact]
        public void GenerateCode_ThrowsIfItemCannotBeFound()
        {
            // Arrange
            var project = new TestRazorProject(new RazorProjectItem[] { });
            var razorEngine = RazorEngine.Create();
            var templateEngine = new RazorTemplateEngine(razorEngine, project);

            // Act & Assert
            var ex = Assert.Throws<InvalidOperationException>(
                () => templateEngine.GenerateCode("/does-not-exist.cstml"));
            Assert.Equal("The item '/does-not-exist.cstml' could not be found.", ex.Message);
        }

        [Fact]
        public void SettingOptions_ThrowsIfValueIsNull()
        {
            // Arrange
            var project = new TestRazorProject(new RazorProjectItem[] { });
            var razorEngine = RazorEngine.Create();
            var templateEngine = new RazorTemplateEngine(razorEngine, project);

            // Act & Assert
            ExceptionAssert.ThrowsArgumentNull(
                () => templateEngine.Options = null,
                "value");
        }

        [Fact]
        public void GenerateCode_WithPath()
        {
            // Arrange
            var path = "/Views/Home/Index.cshtml";
            var projectItem = new TestRazorProjectItem(path);
            var project = new TestRazorProject(new[] { projectItem });
            var razorEngine = RazorEngine.Create();
            var templateEngine = new RazorTemplateEngine(razorEngine, project);

            // Act
            var cSharpDocument = templateEngine.GenerateCode(path);

            // Assert
            Assert.NotNull(cSharpDocument);
            Assert.NotEmpty(cSharpDocument.GeneratedCode);
            Assert.Empty(cSharpDocument.Diagnostics);
        }

        [Fact]
        public void GenerateCode_ThrowsIfProjectItemCannotBeFound()
        {
            // Arrange
            var path = "/Views/Home/Index.cshtml";
            var project = new TestRazorProject(new RazorProjectItem[] { });
            var razorEngine = RazorEngine.Create();
            var templateEngine = new RazorTemplateEngine(razorEngine, project);

            // Act & Assert
            var ex = Assert.Throws<InvalidOperationException>(() => templateEngine.GenerateCode(path));
            Assert.Equal($"The item '{path}' could not be found.", ex.Message);
        }

        [Fact]
        public void GenerateCode_WithProjectItem()
        {
            // Arrange
            var path = "/Views/Home/Index.cshtml";
            var projectItem = new TestRazorProjectItem(path);
            var project = new TestRazorProject(new[] { projectItem });
            var razorEngine = RazorEngine.Create();
            var templateEngine = new RazorTemplateEngine(razorEngine, project);

            // Act
            var cSharpDocument = templateEngine.GenerateCode(projectItem);

            // Assert
            Assert.NotNull(cSharpDocument);
            Assert.NotEmpty(cSharpDocument.GeneratedCode);
            Assert.Empty(cSharpDocument.Diagnostics);
        }

        [Fact]
        public void GenerateCode_WithCodeDocument()
        {
            // Arrange
            var path = "/Views/Home/Index.cshtml";
            var projectItem = new TestRazorProjectItem(path);
            var project = new TestRazorProject(new[] { projectItem });
            var razorEngine = RazorEngine.Create();
            var templateEngine = new RazorTemplateEngine(razorEngine, project);

            // Act - 1
            var codeDocument = templateEngine.CreateCodeDocument(path);

            // Assert - 1
            Assert.NotNull(codeDocument);

            // Act - 2
            var cSharpDocument = templateEngine.GenerateCode(codeDocument);

            // Assert
            Assert.NotNull(cSharpDocument);
            Assert.NotEmpty(cSharpDocument.GeneratedCode);
            Assert.Empty(cSharpDocument.Diagnostics);
        }

        [Fact]
        public void CreateCodeDocument_ThrowsIfPathCannotBeFound()
        {
            // Arrange
            var projectItem = new TestRazorProjectItem("/Views/Home/Index.cshtml");
            var project = new TestRazorProject(new[] { projectItem });
            var razorEngine = RazorEngine.Create();
            var templateEngine = new RazorTemplateEngine(razorEngine, project)
            {
                Options =
                {
                    ImportsFileName = "MyImport.cshtml",
                }
            };

            // Act & Assert
            var ex = Assert.Throws<InvalidOperationException>(() => templateEngine.CreateCodeDocument("/DoesNotExist.cshtml"));

            // Assert
            Assert.Equal("The item '/DoesNotExist.cshtml' could not be found.", ex.Message);
        }

        [Fact]
        public void CreateCodeDocument_IncludesImportsIfFileIsPresent()
        {
            // Arrange
            var projectItem = new TestRazorProjectItem("/Views/Home/Index.cshtml");
            var import1 = new TestRazorProjectItem("/MyImport.cshtml");
            var import2 = new TestRazorProjectItem("/Views/Home/MyImport.cshtml");
            var project = new TestRazorProject(new[] { import1, import2, projectItem });
            var razorEngine = RazorEngine.Create();
            var templateEngine = new RazorTemplateEngine(razorEngine, project)
            {
                Options =
                {
                    ImportsFileName = "MyImport.cshtml",
                }
            };

            // Act
            var codeDocument = templateEngine.CreateCodeDocument("/Views/Home/Index.cshtml");

            // Assert
            Assert.Collection(codeDocument.Imports,
                import => Assert.Equal("/MyImport.cshtml", import.FilePath),
                import => Assert.Equal("/Views/Home/MyImport.cshtml", import.FilePath));
        }

        [Fact]
        public void CreateCodeDocument_IncludesDefaultImportIfNotNull()
        {
            // Arrange
            var projectItem = new TestRazorProjectItem("/Views/Home/Index.cshtml");
            var import1 = new TestRazorProjectItem("/MyImport.cshtml");
            var import2 = new TestRazorProjectItem("/Views/Home/MyImport.cshtml");
            var project = new TestRazorProject(new[] { import1, import2, projectItem });
            var razorEngine = RazorEngine.Create();
            var defaultImport = RazorSourceDocument.ReadFrom(new MemoryStream(), "Default.cshtml");
            var templateEngine = new RazorTemplateEngine(razorEngine, project)
            {
                Options =
                {
                    ImportsFileName = "MyImport.cshtml",
                    DefaultImports = defaultImport,
                }
            };

            // Act
            var codeDocument = templateEngine.CreateCodeDocument(projectItem);

            // Assert
            Assert.Collection(codeDocument.Imports,
                import => Assert.Same(defaultImport, import),
                import => Assert.Equal("/MyImport.cshtml", import.FilePath),
                import => Assert.Equal("/Views/Home/MyImport.cshtml", import.FilePath));
        }

        [Fact]
        public void CreateCodeDocument_NullImportFileName_IncludesDefaultImportIfNotNull()
        {
            // Arrange
            var projectItem = new TestRazorProjectItem("/Views/Home/Index.cshtml");
            var project = new TestRazorProject(new[] { projectItem });
            var razorEngine = RazorEngine.Create();
            var defaultImport = RazorSourceDocument.ReadFrom(new MemoryStream(), "Default.cshtml");
            var templateEngine = new RazorTemplateEngine(razorEngine, project)
            {
                Options =
                {
                    DefaultImports = defaultImport,
                }
            };

            // Act
            var codeDocument = templateEngine.CreateCodeDocument(projectItem);

            // Assert
            Assert.Collection(codeDocument.Imports,
                import => Assert.Same(defaultImport, import));
        }

        [Fact]
        public void GetImportItems_WithPath_ReturnsAllImportsForFile()
        {
            // Arrange
            var expected = new[] { "/Views/Home/MyImport.cshtml", "/Views/MyImport.cshtml", "/MyImport.cshtml" };
            var project = new TestRazorProject();
            var razorEngine = RazorEngine.Create();
            var templateEngine = new RazorTemplateEngine(razorEngine, project)
            {
                Options =
                {
                    ImportsFileName = "MyImport.cshtml"
                }
            };

            // Act
            var imports = templateEngine.GetImportItems("/Views/Home/Index.cshtml");

            // Assert
            var paths = imports.Select(i => i.FilePath);
            Assert.Equal(expected, paths);
        }

        [Fact]
        public void GetImportItems_WithItem_ReturnsAllImportsForFile()
        {
            // Arrange
            var expected = new[] { "/Views/Home/MyImport.cshtml", "/Views/MyImport.cshtml", "/MyImport.cshtml" };
            var projectItem = new TestRazorProjectItem("/Views/Home/Index.cshtml");
            var project = new TestRazorProject(new[] { projectItem });
            var razorEngine = RazorEngine.Create();
            var templateEngine = new RazorTemplateEngine(razorEngine, project)
            {
                Options =
                {
                    ImportsFileName = "MyImport.cshtml"
                }
            };

            // Act
            var imports = templateEngine.GetImportItems(projectItem);

            // Assert
            var paths = imports.Select(i => i.FilePath);
            Assert.Equal(expected, paths);
        }
    }
}