import Hummingbird
import HummingbirdTesting
import NIOCore
import Testing

import Infrastructure

@testable import WebsiteLibrary

@Suite("NotFoundMiddleware middleware", .tags(.middleware))
struct NotFoundMiddlewareTests {
    
    // MARK: Constants
    
    private let app: Application = .init(router: {
        let router = Router(context: WebsiteRequestContext.self)
        
        router.addMiddleware {
            LocalizationMiddleware()
            NotFoundMiddleware()
        }
        
        router.get("hello") { _, _ in
            "Hello!"
        }

        router.get("boom") { _, _ -> String in
            throw HTTPError(.badRequest)
        }

        return router
    }())
    
    // MARK: Functional tests

    @Test
    func `renders the error page for an unmatched request`() async throws {
        try await app.test(.router) { client in
            try await client.execute(
                uri: "/this-path-does-not-exist",
                method: .get
            ) { response in
                let body = String(buffer: response.body)

                #expect(response.status == .notFound)
                #expect(response.headers[.contentType] == "text/html; charset=utf-8")
                #expect(response.headers[.contentLanguage] == "en")
                #expect(response.headers[.vary] == "Accept-Language")
                #expect(body.contains("Page Not Found"))
            }
        }
    }

    @Test
    func `passes a matched response through untouched`() async throws {
        try await app.test(.router) { client in
            try await client.execute(
                uri: "/hello",
                method: .get
            ) { response in
                #expect(response.status == .ok)
                #expect(response.body == ByteBuffer(string: "Hello!"))
            }
        }
    }

    @Test
    func `rethrows a non-not-found error unchanged`() async throws {
        try await app.test(.router) { client in
            try await client.execute(
                uri: "/boom",
                method: .get
            ) { response in
                let body = String(buffer: response.body)

                #expect(response.status == .badRequest)
                #expect(!body.contains("Page Not Found"))
            }
        }
    }

    @Test
    func `renders versioned asset URLs when given a version`() async throws {
        try await app(
            assetVersion: "0123456789abcdef"
        ).test(.router) { client in
            try await client.execute(
                uri: "/this-path-does-not-exist",
                method: .get
            ) { response in
                let body = String(buffer: response.body)

                #expect(body.contains("/css/error.css?v=0123456789abcdef"))
                #expect(body.contains("/js/shared.js?v=0123456789abcdef"))
            }
        }
    }

    @Test
    func `renders unversioned asset URLs by default`() async throws {
        try await app.test(.router) { client in
            try await client.execute(
                uri: "/this-path-does-not-exist",
                method: .get
            ) { response in
                let body = String(buffer: response.body)

                #expect(body.contains(#"href="/css/error.css""#))
                #expect(!body.contains("?v="))
            }
        }
    }

    @Test
    func `serves the error page without revalidation headers`() async throws {
        // A `304 Not Modified` only ever stands in for a success, so the error page must not
        // invite revalidation with an entity tag or a cache policy.
        try await app.test(.router) { client in
            try await client.execute(
                uri: "/this-path-does-not-exist",
                method: .get
            ) { response in
                #expect(response.status == .notFound)
                #expect(response.headers[.eTag] == nil)
                #expect(response.headers[.cacheControl] == nil)
            }
        }
    }

    @Test
    func `serves the full error page to a conditional request`() async throws {
        try await app.test(.router) { client in
            try await client.execute(
                uri: "/this-path-does-not-exist",
                method: .get,
                headers: [.ifNoneMatch: "*"]
            ) { response in
                let body = String(buffer: response.body)

                #expect(response.status == .notFound)
                #expect(body.contains("Page Not Found"))
            }
        }
    }

}

// MARK: - Helpers

private extension NotFoundMiddlewareTests {

    // MARK: Methods

    /// Builds an application whose not-found middleware appends the given version token to the
    /// error page's asset URLs.
    /// - Parameter assetVersion: the version token appended to the page's asset URLs.
    /// - Returns: the configured application.
    func app(
        assetVersion: String?
    ) -> some ApplicationProtocol {
        let router = Router(context: WebsiteRequestContext.self)

        router.addMiddleware {
            LocalizationMiddleware()
            NotFoundMiddleware(
                assetVersion: assetVersion
            )
        }

        return Application(router: router)
    }

}