/*

 * Copyright (c) 2020, Hunter Salyer <thefalsehonesty@gmail.com>

 *

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

 */

#include <AK/HashTable.h>

#include <AK/StringBuilder.h>

#include <AK/TypeCasts.h>

#include <LibJS/Lexer.h>

#include <LibJS/MarkupGenerator.h>

#include <LibJS/Runtime/Array.h>

#include <LibJS/Runtime/Date.h>

#include <LibJS/Runtime/DatePrototype.h>

#include <LibJS/Runtime/Error.h>

#include <LibJS/Runtime/Object.h>

#include <LibJS/Runtime/VM.h>

namespace JS {

ErrorOr<String> MarkupGenerator::html_from_source(StringView source)

{

    StringBuilder builder;

    auto lexer = Lexer(source);

    for (auto token = lexer.next(); token.type() != TokenType::Eof; token = lexer.next()) {

        TRY(builder.try_append(token.trivia()));

        TRY(builder.try_append(TRY(wrap_string_in_style(token.value(), style_type_for_token(token)))));

    }

    return builder.to_string();

}

ErrorOr<String> MarkupGenerator::html_from_value(Value value)

{

    StringBuilder output_html;

    HashTable<Object*> seen_objects;

    TRY(value_to_html(value, output_html, seen_objects));

    return output_html.to_string();

}

ErrorOr<String> MarkupGenerator::html_from_error(Error const& object, bool in_promise)

{

    StringBuilder output_html;

    TRY(error_to_html(object, output_html, in_promise));

    return output_html.to_string();

}

ErrorOr<void> MarkupGenerator::value_to_html(Value value, StringBuilder& output_html, HashTable<Object*>& seen_objects)

{

    if (value.is_empty()) {

        TRY(output_html.try_append("<empty>"sv));

        return {};

    }

    if (value.is_object()) {

        if (seen_objects.contains(&value.as_object())) {

            // FIXME: Maybe we should only do this for circular references,

            //        not for all reoccurring objects.

            TRY(output_html.try_appendff("<already printed Object {:p}>", &value.as_object()));

            return {};

        }

        seen_objects.set(&value.as_object());

    }

    if (value.is_object()) {

        auto& object = value.as_object();

        if (is<Array>(object))

            return array_to_html(static_cast<Array const&>(object), output_html, seen_objects);

        TRY(output_html.try_append(TRY(wrap_string_in_style(object.class_name(), StyleType::ObjectType))));

        if (object.is_function())

            return function_to_html(object, output_html, seen_objects);

        if (is<Date>(object))

            return date_to_html(object, output_html, seen_objects);

        return object_to_html(object, output_html, seen_objects);

    }

    if (value.is_string())

        TRY(output_html.try_append(TRY(open_style_type(StyleType::String))));

    else if (value.is_number())

        TRY(output_html.try_append(TRY(open_style_type(StyleType::Number))));

    else if (value.is_boolean() || value.is_nullish())

        TRY(output_html.try_append(TRY(open_style_type(StyleType::KeywordBold))));

    if (value.is_string())

        TRY(output_html.try_append('"'));

    TRY(output_html.try_append(escape_html_entities(value.to_string_without_side_effects())));

    if (value.is_string())

        TRY(output_html.try_append('"'));

    TRY(output_html.try_append("</span>"sv));

    return {};

}

ErrorOr<void> MarkupGenerator::array_to_html(Array const& array, StringBuilder& html_output, HashTable<Object*>& seen_objects)

{

    TRY(html_output.try_append(TRY(wrap_string_in_style("[ "sv, StyleType::Punctuation))));

    bool first = true;

    for (auto it = array.indexed_properties().begin(false); it != array.indexed_properties().end(); ++it) {

        if (!first)

            TRY(html_output.try_append(TRY(wrap_string_in_style(", "sv, StyleType::Punctuation))));

        first = false;

        // FIXME: Exception check

        TRY(value_to_html(array.get(it.index()).release_value(), html_output, seen_objects));

    }

    TRY(html_output.try_append(TRY(wrap_string_in_style(" ]"sv, StyleType::Punctuation))));

    return {};

}

ErrorOr<void> MarkupGenerator::object_to_html(Object const& object, StringBuilder& html_output, HashTable<Object*>& seen_objects)

{

    TRY(html_output.try_append(TRY(wrap_string_in_style("{ "sv, StyleType::Punctuation))));

    bool first = true;

    for (auto& entry : object.indexed_properties()) {

        if (!first)

            TRY(html_output.try_append(TRY(wrap_string_in_style(", "sv, StyleType::Punctuation))));

        first = false;

        TRY(html_output.try_append(TRY(wrap_string_in_style(String::number(entry.index()), StyleType::Number))));

        TRY(html_output.try_append(TRY(wrap_string_in_style(": "sv, StyleType::Punctuation))));

        // FIXME: Exception check

        TRY(value_to_html(object.get(entry.index()).release_value(), html_output, seen_objects));

    }

    if (!object.indexed_properties().is_empty() && object.shape().property_count())

        TRY(html_output.try_append(TRY(wrap_string_in_style(", "sv, StyleType::Punctuation))));

    size_t index = 0;

    for (auto& it : object.shape().property_table()) {

        TRY(html_output.try_append(TRY(wrap_string_in_style(TRY(String::formatted("\"{}\"", escape_html_entities(it.key.to_display_string()))), StyleType::String))));

        TRY(html_output.try_append(TRY(wrap_string_in_style(": "sv, StyleType::Punctuation))));

        TRY(value_to_html(object.get_direct(it.value.offset), html_output, seen_objects));

        if (index != object.shape().property_count() - 1)

            TRY(html_output.try_append(TRY(wrap_string_in_style(", "sv, StyleType::Punctuation))));

        ++index;

    }

    TRY(html_output.try_append(TRY(wrap_string_in_style(" }"sv, StyleType::Punctuation))));

    return {};

}

ErrorOr<void> MarkupGenerator::function_to_html(Object const& function, StringBuilder& html_output, HashTable<Object*>&)

{

    TRY(html_output.try_appendff("[{}]", function.class_name()));

    return {};

}

ErrorOr<void> MarkupGenerator::date_to_html(Object const& date, StringBuilder& html_output, HashTable<Object*>&)

{

    TRY(html_output.try_appendff("Date {}", to_date_string(static_cast<Date const&>(date).date_value())));

    return {};

}

ErrorOr<void> MarkupGenerator::trace_to_html(TracebackFrame const& traceback_frame, StringBuilder& html_output)

{

    auto function_name = escape_html_entities(traceback_frame.function_name);

    auto [line, column, _] = traceback_frame.source_range().start;

    auto get_filename_from_path = [&](StringView filename) -> StringView {

        auto last_slash_index = filename.find_last('/');

        return last_slash_index.has_value() ? filename.substring_view(*last_slash_index + 1) : filename;

    };

    auto filename = escape_html_entities(get_filename_from_path(traceback_frame.source_range().filename()));

    auto trace = TRY(String::formatted("at {} ({}:{}:{})", function_name, filename, line, column));

    TRY(html_output.try_appendff("&nbsp;&nbsp;{}<br>", trace));

    return {};

}

ErrorOr<void> MarkupGenerator::error_to_html(Error const& error, StringBuilder& html_output, bool in_promise)

{

    auto& vm = error.vm();

    auto name = error.get_without_side_effects(vm.names.name).value_or(js_undefined());

    auto message = error.get_without_side_effects(vm.names.message).value_or(js_undefined());

    auto name_string = name.to_string_without_side_effects();

    auto message_string = message.to_string_without_side_effects();

    auto uncaught_message = TRY(String::formatted("Uncaught {}[{}]: ", in_promise ? "(in promise) " : "", name_string));

    TRY(html_output.try_append(TRY(wrap_string_in_style(uncaught_message, StyleType::Invalid))));

    TRY(html_output.try_appendff("{}<br>", message_string.is_empty() ? "\"\"" : escape_html_entities(message_string)));

    for (size_t i = 0; i < error.traceback().size() - min(error.traceback().size(), 3); i++) {

        auto& traceback_frame = error.traceback().at(i);

        TRY(trace_to_html(traceback_frame, html_output));

    }

    return {};

}

StringView MarkupGenerator::style_from_style_type(StyleType type)

{

    switch (type) {

    case StyleType::Invalid:

        return "color: red;"sv;

    case StyleType::String:

        return "color: -libweb-palette-syntax-string;"sv;

    case StyleType::Number:

        return "color: -libweb-palette-syntax-number;"sv;

    case StyleType::KeywordBold:

        return "color: -libweb-palette-syntax-keyword; font-weight: bold;"sv;

    case StyleType::Punctuation:

        return "color: -libweb-palette-syntax-punctuation;"sv;

    case StyleType::Operator:

        return "color: -libweb-palette-syntax-operator;"sv;

    case StyleType::Keyword:

        return "color: -libweb-palette-syntax-keyword;"sv;

    case StyleType::ControlKeyword:

        return "color: -libweb-palette-syntax-control-keyword;"sv;

    case StyleType::Identifier:

        return "color: -libweb-palette-syntax-identifier;"sv;

    case StyleType::ObjectType:

        return "padding: 2px; background-color: #ddf; color: black; font-weight: bold;"sv;

    default:

        VERIFY_NOT_REACHED();

    }

}

MarkupGenerator::StyleType MarkupGenerator::style_type_for_token(Token token)

{

    switch (token.category()) {

    case TokenCategory::Invalid:

        return StyleType::Invalid;

    case TokenCategory::Number:

        return StyleType::Number;

    case TokenCategory::String:

        return StyleType::String;

    case TokenCategory::Punctuation:

        return StyleType::Punctuation;

    case TokenCategory::Operator:

        return StyleType::Operator;

    case TokenCategory::Keyword:

        switch (token.type()) {

        case TokenType::BoolLiteral:

        case TokenType::NullLiteral:

            return StyleType::KeywordBold;

        default:

            return StyleType::Keyword;

        }

    case TokenCategory::ControlKeyword:

        return StyleType::ControlKeyword;

    case TokenCategory::Identifier:

        return StyleType::Identifier;

    default:

        dbgln("Unknown style type for token {}", token.name());

        VERIFY_NOT_REACHED();

    }

}

ErrorOr<String> MarkupGenerator::open_style_type(StyleType type)

{

    return String::formatted("<span style=\"{}\">", style_from_style_type(type));

}

ErrorOr<String> MarkupGenerator::wrap_string_in_style(StringView source, StyleType type)

{

    return String::formatted("<span style=\"{}\">{}</span>", style_from_style_type(type), escape_html_entities(source));

}

}