/*

 * Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>

 * Copyright (c) 2024, Andreas Kling <kling@serenityos.org>

 * Copyright (c) 2024, Shannon Booth <shannon@serenityos.org>

 *

 * SPDX-License-Identifier: BSD-2-Clause

 */

#include <AK/StringBuilder.h>

#include <LibURL/Origin.h>

#include <LibURL/URL.h>

#include <LibWeb/Crypto/Crypto.h>

#include <LibWeb/DOM/Document.h>

#include <LibWeb/FileAPI/Blob.h>

#include <LibWeb/FileAPI/BlobURLStore.h>

#include <LibWeb/HTML/Scripting/Environments.h>

namespace Web::FileAPI {

BlobURLStore& blob_url_store()

{

    static HashMap<String, BlobURLEntry> store;

    return store;

}

// https://w3c.github.io/FileAPI/#unicodeBlobURL

ErrorOr<String> generate_new_blob_url()

{

    // 1. Let result be the empty string.

    StringBuilder result;

    // 2. Append the string "blob:" to result.

    TRY(result.try_append("blob:"sv));

    // 3. Let settings be the current settings object

    auto& settings = HTML::current_settings_object();

    // 4. Let origin be settings’s origin.

    auto origin = settings.origin();

    // 5. Let serialized be the ASCII serialization of origin.

    auto serialized = origin.serialize();

    // 6. If serialized is "null", set it to an implementation-defined value.

    if (serialized == "null"sv)

        serialized = "ladybird"sv;

    // 7. Append serialized to result.

    TRY(result.try_append(serialized));

    // 8. Append U+0024 SOLIDUS (/) to result.

    TRY(result.try_append('/'));

    // 9. Generate a UUID [RFC4122] as a string and append it to result.

    auto uuid = TRY(Crypto::generate_random_uuid());

    TRY(result.try_append(uuid));

    // 10. Return result.

    return result.to_string();

}

// https://w3c.github.io/FileAPI/#add-an-entry

ErrorOr<String> add_entry_to_blob_url_store(JS::NonnullGCPtr<Blob> object)

{

    // 1. Let store be the user agent’s blob URL store.

    auto& store = blob_url_store();

    // 2. Let url be the result of generating a new blob URL.

    auto url = TRY(generate_new_blob_url());

    // 3. Let entry be a new blob URL entry consisting of object and the current settings object.

    BlobURLEntry entry { object, HTML::current_settings_object() };

    // 4. Set store[url] to entry.

    TRY(store.try_set(url, move(entry)));

    // 5. Return url.

    return url;

}

// https://w3c.github.io/FileAPI/#removeTheEntry

ErrorOr<void> remove_entry_from_blob_url_store(StringView url)

{

    // 1. Let store be the user agent’s blob URL store;

    auto& store = blob_url_store();

    // 2. Let url string be the result of serializing url.

    auto url_string = TRY(URL::URL { url }.to_string());

    // 3. Remove store[url string].

    store.remove(url_string);

    return {};

}

// https://w3c.github.io/FileAPI/#lifeTime

void run_unloading_cleanup_steps(JS::NonnullGCPtr<DOM::Document> document)

{

    // 1.  Let environment be the Document's relevant settings object.

    auto& environment = document->relevant_settings_object();

    // 2.  Let store be the user agent’s blob URL store;

    auto& store = FileAPI::blob_url_store();

    // 3. Remove from store any entries for which the value's environment is equal to environment.

    store.remove_all_matching([&](auto&, auto& value) {

        return value.environment == &environment;

    });

}

// https://w3c.github.io/FileAPI/#blob-url-resolve

Optional<BlobURLEntry> resolve_a_blob_url(URL::URL const& url)

{

    // 1. Assert: url’s scheme is "blob".

    VERIFY(url.scheme() == "blob"sv);

    // 2. Let store be the user agent’s blob URL store.

    auto& store = blob_url_store();

    // 3. Let url string be the result of serializing url with the exclude fragment flag set.

    auto url_string = MUST(String::from_byte_string(url.serialize(URL::ExcludeFragment::Yes)));

    // 4. If store[url string] exists, return store[url string]; otherwise return failure.

    return store.get(url_string).copy();

}

}