/*
 * Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <AK/Base64.h>
#include <AK/JsonArray.h>
#include <AK/JsonObject.h>
#include <AK/StringBuilder.h>
#include <LibCore/Resource.h>
#include <LibJS/MarkupGenerator.h>
#include <LibWeb/Infra/Strings.h>
#include <LibWebView/InspectorClient.h>
#include <LibWebView/SourceHighlighter.h>

namespace WebView {

static ErrorOr<JsonValue> parse_json_tree(StringView json)
{
    auto parsed_tree = TRY(JsonValue::from_string(json));
    if (!parsed_tree.is_object())
        return Error::from_string_literal("Expected tree to be a JSON object");

    return parsed_tree;
}

InspectorClient::InspectorClient(ViewImplementation& content_web_view, ViewImplementation& inspector_web_view)
    : m_content_web_view(content_web_view)
    , m_inspector_web_view(inspector_web_view)
{
    m_content_web_view.on_received_dom_tree = [this](auto const& dom_tree) {
        auto result = parse_json_tree(dom_tree);
        if (result.is_error()) {
            dbgln("Failed to load DOM tree: {}", result.error());
            return;
        }

        auto dom_tree_html = generate_dom_tree(result.value().as_object());
        auto dom_tree_base64 = MUST(encode_base64(dom_tree_html.bytes()));

        auto script = MUST(String::formatted("inspector.loadDOMTree(\"{}\");", dom_tree_base64));
        m_inspector_web_view.run_javascript(script);

        m_dom_tree_loaded = true;

        if (m_pending_selection.has_value())
            select_node(m_pending_selection.release_value());
        else
            select_default_node();
    };

    m_content_web_view.on_received_accessibility_tree = [this](auto const& accessibility_tree) {
        auto result = parse_json_tree(accessibility_tree);
        if (result.is_error()) {
            dbgln("Failed to load accessibility tree: {}", result.error());
            return;
        }

        auto accessibility_tree_html = generate_accessibility_tree(result.value().as_object());
        auto accessibility_tree_base64 = MUST(encode_base64(accessibility_tree_html.bytes()));

        auto script = MUST(String::formatted("inspector.loadAccessibilityTree(\"{}\");", accessibility_tree_base64));
        m_inspector_web_view.run_javascript(script);
    };

    m_content_web_view.on_received_console_message = [this](auto message_index) {
        handle_console_message(message_index);
    };

    m_content_web_view.on_received_console_messages = [this](auto start_index, auto const& message_types, auto const& messages) {
        handle_console_messages(start_index, message_types, messages);
    };

    m_inspector_web_view.enable_inspector_prototype();
    m_inspector_web_view.use_native_user_style_sheet();

    m_inspector_web_view.on_inspector_loaded = [this]() {
        inspect();

        m_content_web_view.js_console_request_messages(0);
    };

    m_inspector_web_view.on_inspector_requested_dom_tree_context_menu = [this](auto node_id, auto position, auto const& type, auto const& tag, auto const& attribute) {
        m_context_menu_data = ContextMenuData { node_id, tag, attribute };

        if (type.is_one_of("text"sv, "comment"sv)) {
            if (on_requested_dom_node_text_context_menu)
                on_requested_dom_node_text_context_menu(position);
        } else if (type == "tag"sv) {
            VERIFY(tag.has_value());

            if (on_requested_dom_node_tag_context_menu)
                on_requested_dom_node_tag_context_menu(position, *tag);
        } else if (type == "attribute"sv) {
            VERIFY(tag.has_value());
            VERIFY(attribute.has_value());

            if (on_requested_dom_node_attribute_context_menu)
                on_requested_dom_node_attribute_context_menu(position, *tag, *attribute);
        }
    };

    m_inspector_web_view.on_inspector_selected_dom_node = [this](auto node_id, auto const& pseudo_element) {
        auto inspected_node_properties = m_content_web_view.inspect_dom_node(node_id, pseudo_element);

        StringBuilder builder;

        // FIXME: Support box model metrics and ARIA properties.
        auto generate_property_script = [&](auto const& computed_style, auto const& resolved_style, auto const& custom_properties) {
            builder.append("inspector.createPropertyTables(\""sv);
            builder.append_escaped_for_json(computed_style);
            builder.append("\", \""sv);
            builder.append_escaped_for_json(resolved_style);
            builder.append("\", \""sv);
            builder.append_escaped_for_json(custom_properties);
            builder.append("\");"sv);
        };

        if (inspected_node_properties.is_error()) {
            generate_property_script("{}"sv, "{}"sv, "{}"sv);
        } else {
            generate_property_script(
                inspected_node_properties.value().computed_style_json,
                inspected_node_properties.value().resolved_style_json,
                inspected_node_properties.value().custom_properties_json);
        }

        m_inspector_web_view.run_javascript(builder.string_view());
    };

    m_inspector_web_view.on_inspector_set_dom_node_text = [this](auto node_id, auto const& text) {
        m_content_web_view.set_dom_node_text(node_id, text);

        m_pending_selection = node_id;
        inspect();
    };

    m_inspector_web_view.on_inspector_set_dom_node_tag = [this](auto node_id, auto const& tag) {
        m_pending_selection = m_content_web_view.set_dom_node_tag(node_id, tag);
        inspect();
    };

    m_inspector_web_view.on_inspector_added_dom_node_attributes = [this](auto node_id, auto const& attributes) {
        m_content_web_view.add_dom_node_attributes(node_id, attributes);

        m_pending_selection = node_id;
        inspect();
    };

    m_inspector_web_view.on_inspector_replaced_dom_node_attribute = [this](auto node_id, auto const& name, auto const& replacement_attributes) {
        m_content_web_view.replace_dom_node_attribute(node_id, name, replacement_attributes);

        m_pending_selection = node_id;
        inspect();
    };

    m_inspector_web_view.on_inspector_executed_console_script = [this](auto const& script) {
        append_console_source(script);

        m_content_web_view.js_console_input(script.to_deprecated_string());
    };

    load_inspector();
}

InspectorClient::~InspectorClient()
{
    m_content_web_view.on_received_dom_tree = nullptr;
    m_content_web_view.on_received_accessibility_tree = nullptr;
    m_content_web_view.on_received_console_message = nullptr;
    m_content_web_view.on_received_console_messages = nullptr;
}

void InspectorClient::inspect()
{
    if (m_dom_tree_loaded)
        return;

    m_content_web_view.inspect_dom_tree();
    m_content_web_view.inspect_accessibility_tree();
}

void InspectorClient::reset()
{
    static constexpr auto script = "inspector.reset();"sv;
    m_inspector_web_view.run_javascript(script);

    m_body_node_id.clear();
    m_pending_selection.clear();
    m_dom_tree_loaded = false;

    m_highest_notified_message_index = -1;
    m_highest_received_message_index = -1;
    m_waiting_for_messages = false;
}

void InspectorClient::select_hovered_node()
{
    auto hovered_node_id = m_content_web_view.get_hovered_node_id();
    select_node(hovered_node_id);
}

void InspectorClient::select_default_node()
{
    if (m_body_node_id.has_value())
        select_node(*m_body_node_id);
}

void InspectorClient::clear_selection()
{
    m_content_web_view.clear_inspected_dom_node();

    static constexpr auto script = "inspector.clearInspectedDOMNode();"sv;
    m_inspector_web_view.run_javascript(script);
}

void InspectorClient::select_node(i32 node_id)
{
    if (!m_dom_tree_loaded) {
        m_pending_selection = node_id;
        return;
    }

    auto script = MUST(String::formatted("inspector.inspectDOMNodeID({});", node_id));
    m_inspector_web_view.run_javascript(script);
}

void InspectorClient::context_menu_edit_dom_node()
{
    VERIFY(m_context_menu_data.has_value());

    auto script = MUST(String::formatted("inspector.editDOMNodeID({});", m_context_menu_data->dom_node_id));
    m_inspector_web_view.run_javascript(script);

    m_context_menu_data.clear();
}

void InspectorClient::context_menu_copy_dom_node()
{
    VERIFY(m_context_menu_data.has_value());

    if (auto html = m_content_web_view.get_dom_node_html(m_context_menu_data->dom_node_id); html.has_value()) {
        if (m_content_web_view.on_insert_clipboard_entry)
            m_content_web_view.on_insert_clipboard_entry(*html, "unspecified"_string, "text/plain"_string);
    }

    m_context_menu_data.clear();
}

void InspectorClient::context_menu_screenshot_dom_node()
{
    VERIFY(m_context_menu_data.has_value());

    if (auto result = m_content_web_view.take_dom_node_screenshot(m_context_menu_data->dom_node_id); result.is_error())
        append_console_warning(MUST(String::formatted("Warning: {}", result.error())));
    else
        append_console_message(MUST(String::formatted("Screenshot saved to: {}", result.value())));

    m_context_menu_data.clear();
}

void InspectorClient::context_menu_create_child_element()
{
    VERIFY(m_context_menu_data.has_value());

    m_pending_selection = m_content_web_view.create_child_element(m_context_menu_data->dom_node_id);
    inspect();

    m_context_menu_data.clear();
}

void InspectorClient::context_menu_create_child_text_node()
{
    VERIFY(m_context_menu_data.has_value());

    m_pending_selection = m_content_web_view.create_child_text_node(m_context_menu_data->dom_node_id);
    inspect();

    m_context_menu_data.clear();
}

void InspectorClient::context_menu_clone_dom_node()
{
    VERIFY(m_context_menu_data.has_value());

    m_pending_selection = m_content_web_view.clone_dom_node(m_context_menu_data->dom_node_id);
    inspect();

    m_context_menu_data.clear();
}

void InspectorClient::context_menu_remove_dom_node()
{
    VERIFY(m_context_menu_data.has_value());

    m_content_web_view.remove_dom_node(m_context_menu_data->dom_node_id);

    m_pending_selection = m_body_node_id;
    inspect();

    m_context_menu_data.clear();
}

void InspectorClient::context_menu_add_dom_node_attribute()
{
    VERIFY(m_context_menu_data.has_value());

    auto script = MUST(String::formatted("inspector.addAttributeToDOMNodeID({});", m_context_menu_data->dom_node_id));
    m_inspector_web_view.run_javascript(script);

    m_context_menu_data.clear();
}

void InspectorClient::context_menu_remove_dom_node_attribute()
{
    VERIFY(m_context_menu_data.has_value());
    VERIFY(m_context_menu_data->attribute.has_value());

    m_content_web_view.replace_dom_node_attribute(m_context_menu_data->dom_node_id, m_context_menu_data->attribute->name, {});

    m_pending_selection = m_context_menu_data->dom_node_id;
    inspect();

    m_context_menu_data.clear();
}

void InspectorClient::context_menu_copy_dom_node_attribute_value()
{
    VERIFY(m_context_menu_data.has_value());
    VERIFY(m_context_menu_data->attribute.has_value());

    if (m_content_web_view.on_insert_clipboard_entry)
        m_content_web_view.on_insert_clipboard_entry(m_context_menu_data->attribute->value, "unspecified"_string, "text/plain"_string);

    m_context_menu_data.clear();
}

void InspectorClient::load_inspector()
{
    StringBuilder builder;

    // FIXME: Teach LibWeb how to load resource:// URIs instead of needing to read these files here.
    auto inspector_css = MUST(Core::Resource::load_from_uri("resource://ladybird/inspector.css"sv));
    auto inspector_js = MUST(Core::Resource::load_from_uri("resource://ladybird/inspector.js"sv));

    builder.append(R"~~~(
<!DOCTYPE html>
<html>
<head>
    <meta name="color-scheme" content="dark light">
    <style type="text/css">
)~~~"sv);

    builder.append(HTML_HIGHLIGHTER_STYLE);
    builder.append(inspector_css->data());

    builder.append(R"~~~(
    </style>
</head>
<body>
    <div class="split-view">
        <div id="inspector-top" class="split-view-container" style="height: 60%">
            <div class="tab-controls-container">
                <div class="tab-controls">
                    <button id="dom-tree-button" onclick="selectTopTab(this, 'dom-tree')">DOM Tree</button>
                    <button id="accessibility-tree-button" onclick="selectTopTab(this, 'accessibility-tree')">Accessibility Tree</button>
                </div>
            </div>
            <div id="dom-tree" class="tab-content html"></div>
            <div id="accessibility-tree" class="tab-content"></div>
        </div>
        <div id="inspector-separator" class="split-view-separator">
            <svg viewBox="0 0 16 5" xmlns="http://www.w3.org/2000/svg">
                <circle cx="2" cy="2.5" r="2" />
                <circle cx="8" cy="2.5" r="2" />
                <circle cx="14" cy="2.5" r="2" />
            </svg>
        </div>
        <div id="inspector-bottom" class="split-view-container" style="height: calc(40% - 5px)">
            <div class="tab-controls-container">
                <div class="tab-controls">
                    <button id="console-button" onclick="selectBottomTab(this, 'console')">Console</button>
                    <button id="computed-style-button" onclick="selectBottomTab(this, 'computed-style')">Computed Style</button>
                    <button id="resolved-style-button" onclick="selectBottomTab(this, 'resolved-style')">Resolved Style</button>
                    <button id="custom-properties-button" onclick="selectBottomTab(this, 'custom-properties')">Custom Properties</button>
                </div>
            </div>
            <div id="console" class="tab-content">
                <div class="console">
                    <div id="console-output" class="console-output"></div>
                    <div class="console-input">
                        <label for="console-input" class="console-prompt">&gt;&gt;</label>
                        <input id="console-input" type="text" placeholder="Enter statement to execute">
                        <button id="console-clear" title="Clear the console output" onclick="inspector.clearConsoleOutput()">X</button>
                    </div>
                </div>
            </div>
)~~~"sv);

    auto generate_property_table = [&](auto name) {
        builder.appendff(R"~~~(
            <div id="{0}" class="tab-content">
                <table class="property-table">
                    <thead>
                        <tr>
                            <th>Name</th>
                            <th>Value</th>
                        </tr>
                    </thead>
                    <tbody id="{0}-table">
                    </tbody>
                </table>
            </div>
)~~~",
            name);
    };

    generate_property_table("computed-style"sv);
    generate_property_table("resolved-style"sv);
    generate_property_table("custom-properties"sv);

    builder.append(R"~~~(
        </div>
    </div>

    <script type="text/javascript">
)~~~"sv);

    builder.append(inspector_js->data());

    builder.append(R"~~~(
    </script>
</body>
</html>
)~~~"sv);

    m_inspector_web_view.load_html(builder.string_view());
}

template<typename Generator>
static void generate_tree(StringBuilder& builder, JsonObject const& node, Generator&& generator)
{
    if (auto children = node.get_array("children"sv); children.has_value() && !children->is_empty()) {
        auto name = node.get_deprecated_string("name"sv).value_or({});
        builder.append("<details>"sv);

        builder.append("<summary>"sv);
        generator(node);
        builder.append("</summary>"sv);

        children->for_each([&](auto const& child) {
            builder.append("<div>"sv);
            generate_tree(builder, child.as_object(), generator);
            builder.append("</div>"sv);
        });

        builder.append("</details>"sv);
    } else {
        generator(node);
    }
}

String InspectorClient::generate_dom_tree(JsonObject const& dom_tree)
{
    StringBuilder builder;

    generate_tree(builder, dom_tree, [&](JsonObject const& node) {
        auto type = node.get_deprecated_string("type"sv).value_or("unknown"sv);
        auto name = node.get_deprecated_string("name"sv).value_or({});

        StringBuilder data_attributes;
        auto append_data_attribute = [&](auto name, auto value) {
            if (!data_attributes.is_empty())
                data_attributes.append(' ');
            data_attributes.appendff("data-{}=\"{}\"", name, value);
        };

        if (auto pseudo_element = node.get_integer<i32>("pseudo-element"sv); pseudo_element.has_value()) {
            append_data_attribute("id"sv, node.get_integer<i32>("parent-id"sv).value());
            append_data_attribute("pseudo-element"sv, *pseudo_element);
        } else {
            append_data_attribute("id"sv, node.get_integer<i32>("id"sv).value());
        }

        if (type == "text"sv) {
            auto deprecated_text = node.get_deprecated_string("text"sv).release_value();
            deprecated_text = escape_html_entities(deprecated_text);

            auto text = MUST(Web::Infra::strip_and_collapse_whitespace(deprecated_text));
            builder.appendff("<span data-node-type=\"text\" data-text=\"{}\" class=\"hoverable editable\" {}>", text, data_attributes.string_view());

            if (text.is_empty())
                builder.appendff("<span class=\"internal\">{}</span>", name);
            else
                builder.append(text);

            builder.append("</span>"sv);
            return;
        }

        if (type == "comment"sv) {
            auto comment = node.get_deprecated_string("data"sv).release_value();
            comment = escape_html_entities(comment);

            builder.appendff("<span class=\"hoverable comment\" {}>", data_attributes.string_view());
            builder.append("<span>&lt;!--</span>"sv);
            builder.appendff("<span data-node-type=\"comment\" class=\"editable\">{}</span>", comment);
            builder.append("<span>--&gt;</span>"sv);
            builder.append("</span>"sv);
            return;
        }

        if (type == "shadow-root"sv) {
            auto mode = node.get_deprecated_string("mode"sv).release_value();

            builder.appendff("<span class=\"hoverable internal\" {}>", data_attributes.string_view());
            builder.appendff("{} ({})", name, mode);
            builder.append("</span>"sv);
            return;
        }

        if (type != "element"sv) {
            builder.appendff("<span class=\"hoverable internal\" {}>", data_attributes.string_view());
            builder.appendff(name);
            builder.append("</span>"sv);
            return;
        }

        if (name.equals_ignoring_ascii_case("BODY"sv))
            m_body_node_id = node.get_integer<i32>("id"sv).value();

        auto tag = name.to_lowercase();

        builder.appendff("<span class=\"hoverable\" {}>", data_attributes.string_view());
        builder.append("<span>&lt;</span>"sv);
        builder.appendff("<span data-node-type=\"tag\" data-tag=\"{0}\" class=\"editable tag\">{0}</span>", tag);

        if (auto attributes = node.get_object("attributes"sv); attributes.has_value()) {
            attributes->for_each_member([&](auto const& name, auto const& value) {
                builder.append("&nbsp;"sv);
                builder.appendff("<span data-node-type=\"attribute\"  data-tag=\"{}\" data-attribute-name=\"{}\" data-attribute-value=\"{}\" class=\"editable\">", tag, name, value);
                builder.appendff("<span class=\"attribute-name\">{}</span>", name);
                builder.append('=');
                builder.appendff("<span class=\"attribute-value\">\"{}\"</span>", value);
                builder.append("</span>"sv);
            });
        }

        builder.append("<span>&gt;</span>"sv);
        builder.append("</span>"sv);
    });

    return MUST(builder.to_string());
}

String InspectorClient::generate_accessibility_tree(JsonObject const& accessibility_tree)
{
    StringBuilder builder;

    generate_tree(builder, accessibility_tree, [&](JsonObject const& node) {
        auto type = node.get_deprecated_string("type"sv).value_or("unknown"sv);
        auto role = node.get_deprecated_string("role"sv).value_or({});

        if (type == "text"sv) {
            auto text = node.get_deprecated_string("text"sv).release_value();
            text = escape_html_entities(text);

            builder.appendff("<span class=\"hoverable\">");
            builder.append(MUST(Web::Infra::strip_and_collapse_whitespace(text)));
            builder.append("</span>"sv);
            return;
        }

        if (type != "element"sv) {
            builder.appendff("<span class=\"hoverable internal\">");
            builder.appendff(role.to_lowercase());
            builder.append("</span>"sv);
            return;
        }

        auto name = node.get_deprecated_string("name"sv).value_or({});
        auto description = node.get_deprecated_string("description"sv).value_or({});

        builder.appendff("<span class=\"hoverable\">");
        builder.append(role.to_lowercase());
        builder.appendff(" name: \"{}\", description: \"{}\"", name, description);
        builder.append("</span>"sv);
    });

    return MUST(builder.to_string());
}

void InspectorClient::request_console_messages()
{
    VERIFY(!m_waiting_for_messages);

    m_content_web_view.js_console_request_messages(m_highest_received_message_index + 1);
    m_waiting_for_messages = true;
}

void InspectorClient::handle_console_message(i32 message_index)
{
    if (message_index <= m_highest_received_message_index) {
        dbgln("Notified about console message we already have");
        return;
    }
    if (message_index <= m_highest_notified_message_index) {
        dbgln("Notified about console message we're already aware of");
        return;
    }

    m_highest_notified_message_index = message_index;

    if (!m_waiting_for_messages)
        request_console_messages();
}

void InspectorClient::handle_console_messages(i32 start_index, ReadonlySpan<DeprecatedString> message_types, ReadonlySpan<DeprecatedString> messages)
{
    auto end_index = start_index + static_cast<i32>(message_types.size()) - 1;
    if (end_index <= m_highest_received_message_index) {
        dbgln("Received old console messages");
        return;
    }

    for (size_t i = 0; i < message_types.size(); ++i) {
        auto const& type = message_types[i];
        auto const& message = messages[i];

        if (type == "html"sv)
            append_console_output(message);
        else if (type == "clear"sv)
            clear_console_output();
        else if (type == "group"sv)
            begin_console_group(message, true);
        else if (type == "groupCollapsed"sv)
            begin_console_group(message, false);
        else if (type == "groupEnd"sv)
            end_console_group();
        else
            VERIFY_NOT_REACHED();
    }

    m_highest_received_message_index = end_index;
    m_waiting_for_messages = false;

    if (m_highest_received_message_index < m_highest_notified_message_index)
        request_console_messages();
}

void InspectorClient::append_console_source(StringView source)
{
    StringBuilder builder;
    builder.append("<span class=\"console-prompt\">&gt;&nbsp;</span>"sv);
    builder.append(MUST(JS::MarkupGenerator::html_from_source(source)));

    append_console_output(builder.string_view());
}

void InspectorClient::append_console_message(StringView message)
{
    StringBuilder builder;
    builder.append("<span class=\"console-prompt\">#&nbsp;</span>"sv);
    builder.appendff("<span class=\"console-message\">{}</span>", message);

    append_console_output(builder.string_view());
}

void InspectorClient::append_console_warning(StringView warning)
{
    StringBuilder builder;
    builder.append("<span class=\"console-prompt\">#&nbsp;</span>"sv);
    builder.appendff("<span class=\"console-warning\">{}</span>", warning);

    append_console_output(builder.string_view());
}

void InspectorClient::append_console_output(StringView html)
{
    auto html_base64 = MUST(encode_base64(html.bytes()));

    auto script = MUST(String::formatted("inspector.appendConsoleOutput(\"{}\");", html_base64));
    m_inspector_web_view.run_javascript(script);
}

void InspectorClient::clear_console_output()
{
    static constexpr auto script = "inspector.clearConsoleOutput();"sv;
    m_inspector_web_view.run_javascript(script);
}

void InspectorClient::begin_console_group(StringView label, bool start_expanded)
{
    auto label_base64 = MUST(encode_base64(label.bytes()));

    auto script = MUST(String::formatted("inspector.beginConsoleGroup(\"{}\", {});", label_base64, start_expanded));
    m_inspector_web_view.run_javascript(script);
}

void InspectorClient::end_console_group()
{
    static constexpr auto script = "inspector.endConsoleGroup();"sv;
    m_inspector_web_view.run_javascript(script);
}

}