/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "NameMangler.h"
#include "Resource.h"
#include "ResourceTable.h"
#include "ResourceValues.h"
#include "ValueVisitor.h"

#include "java/AnnotationProcessor.h"
#include "java/ClassDefinitionWriter.h"
#include "java/JavaClassGenerator.h"
#include "process/SymbolTable.h"
#include "util/StringPiece.h"

#include <algorithm>
#include <ostream>
#include <set>
#include <sstream>
#include <tuple>

namespace aapt {

JavaClassGenerator::JavaClassGenerator(IAaptContext* context, ResourceTable* table,
                                       const JavaClassGeneratorOptions& options) :
        mContext(context), mTable(table), mOptions(options) {
}

static void generateHeader(const StringPiece16& packageNameToGenerate, std::ostream* out) {
    *out << "/* AUTO-GENERATED FILE. DO NOT MODIFY.\n"
            " *\n"
            " * This class was automatically generated by the\n"
            " * aapt tool from the resource data it found. It\n"
            " * should not be modified by hand.\n"
            " */\n\n"
            "package " << packageNameToGenerate << ";\n\n";
}

static const std::set<StringPiece16> sJavaIdentifiers = {
    u"abstract", u"assert", u"boolean", u"break", u"byte",
    u"case", u"catch", u"char", u"class", u"const", u"continue",
    u"default", u"do", u"double", u"else", u"enum", u"extends",
    u"final", u"finally", u"float", u"for", u"goto", u"if",
    u"implements", u"import", u"instanceof", u"int", u"interface",
    u"long", u"native", u"new", u"package", u"private", u"protected",
    u"public", u"return", u"short", u"static", u"strictfp", u"super",
    u"switch", u"synchronized", u"this", u"throw", u"throws",
    u"transient", u"try", u"void", u"volatile", u"while", u"true",
    u"false", u"null"
};

static bool isValidSymbol(const StringPiece16& symbol) {
    return sJavaIdentifiers.find(symbol) == sJavaIdentifiers.end();
}

/*
 * Java symbols can not contain . or -, but those are valid in a resource name.
 * Replace those with '_'.
 */
static std::string transform(const StringPiece16& symbol) {
    std::string output = util::utf16ToUtf8(symbol);
    for (char& c : output) {
        if (c == '.' || c == '-') {
            c = '_';
        }
    }
    return output;
}

/**
 * Transforms an attribute in a styleable to the Java field name:
 *
 * <declare-styleable name="Foo">
 *   <attr name="android:bar" />
 *   <attr name="bar" />
 * </declare-styleable>
 *
 * Foo_android_bar
 * Foo_bar
 */
static std::string transformNestedAttr(const ResourceNameRef& attrName,
                                       const std::string& styleableClassName,
                                       const StringPiece16& packageNameToGenerate) {
    std::string output = styleableClassName;

    // We may reference IDs from other packages, so prefix the entry name with
    // the package.
    if (!attrName.package.empty() && packageNameToGenerate != attrName.package) {
        output += "_" + transform(attrName.package);
    }
    output += "_" + transform(attrName.entry);
    return output;
}

static void addAttributeFormatDoc(AnnotationProcessor* processor, Attribute* attr) {
    const uint32_t typeMask = attr->typeMask;
    if (typeMask & android::ResTable_map::TYPE_REFERENCE) {
        processor->appendComment(
                "<p>May be a reference to another resource, in the form\n"
                        "\"<code>@[+][<i>package</i>:]<i>type</i>/<i>name</i></code>\" or a theme\n"
                        "attribute in the form\n"
                        "\"<code>?[<i>package</i>:]<i>type</i>/<i>name</i></code>\".");
    }

    if (typeMask & android::ResTable_map::TYPE_STRING) {
        processor->appendComment(
                "<p>May be a string value, using '\\\\;' to escape characters such as\n"
                        "'\\\\n' or '\\\\uxxxx' for a unicode character;");
    }

    if (typeMask & android::ResTable_map::TYPE_INTEGER) {
        processor->appendComment("<p>May be an integer value, such as \"<code>100</code>\".");
    }

    if (typeMask & android::ResTable_map::TYPE_BOOLEAN) {
        processor->appendComment(
                "<p>May be a boolean value, such as \"<code>true</code>\" or\n"
                        "\"<code>false</code>\".");
    }

    if (typeMask & android::ResTable_map::TYPE_COLOR) {
        processor->appendComment(
                "<p>May be a color value, in the form of \"<code>#<i>rgb</i></code>\",\n"
                        "\"<code>#<i>argb</i></code>\", \"<code>#<i>rrggbb</i></code\", or \n"
                        "\"<code>#<i>aarrggbb</i></code>\".");
    }

    if (typeMask & android::ResTable_map::TYPE_FLOAT) {
        processor->appendComment(
                "<p>May be a floating point value, such as \"<code>1.2</code>\".");
    }

    if (typeMask & android::ResTable_map::TYPE_DIMENSION) {
        processor->appendComment(
                "<p>May be a dimension value, which is a floating point number appended with a\n"
                        "unit such as \"<code>14.5sp</code>\".\n"
                        "Available units are: px (pixels), dp (density-independent pixels),\n"
                        "sp (scaled pixels based on preferred font size), in (inches), and\n"
                        "mm (millimeters).");
    }

    if (typeMask & android::ResTable_map::TYPE_FRACTION) {
        processor->appendComment(
                "<p>May be a fractional value, which is a floating point number appended with\n"
                        "either % or %p, such as \"<code>14.5%</code>\".\n"
                        "The % suffix always means a percentage of the base size;\n"
                        "the optional %p suffix provides a size relative to some parent container.");
    }

    if (typeMask & (android::ResTable_map::TYPE_FLAGS | android::ResTable_map::TYPE_ENUM)) {
        if (typeMask & android::ResTable_map::TYPE_FLAGS) {
            processor->appendComment(
                    "<p>Must be one or more (separated by '|') of the following "
                            "constant values.</p>");
        } else {
            processor->appendComment("<p>Must be one of the following constant values.</p>");
        }

        processor->appendComment("<table>\n<colgroup align=\"left\" />\n"
                                         "<colgroup align=\"left\" />\n"
                                         "<colgroup align=\"left\" />\n"
                                         "<tr><th>Constant</th><th>Value</th><th>Description</th></tr>\n");
        for (const Attribute::Symbol& symbol : attr->symbols) {
            std::stringstream line;
            line << "<tr><td>" << symbol.symbol.name.value().entry << "</td>"
            << "<td>" << std::hex << symbol.value << std::dec << "</td>"
            << "<td>" << util::trimWhitespace(symbol.symbol.getComment()) << "</td></tr>";
            processor->appendComment(line.str());
        }
        processor->appendComment("</table>");
    }
}

bool JavaClassGenerator::skipSymbol(SymbolState state) {
    switch (mOptions.types) {
    case JavaClassGeneratorOptions::SymbolTypes::kAll:
        return false;
    case JavaClassGeneratorOptions::SymbolTypes::kPublicPrivate:
        return state == SymbolState::kUndefined;
    case JavaClassGeneratorOptions::SymbolTypes::kPublic:
        return state != SymbolState::kPublic;
    }
    return true;
}

struct StyleableAttr {
    const Reference* attrRef;
    std::shared_ptr<Attribute> attribute;
    std::string fieldName;
};

static bool lessStyleableAttr(const StyleableAttr& lhs, const StyleableAttr& rhs) {
    const ResourceId lhsId = lhs.attrRef->id ? lhs.attrRef->id.value() : ResourceId(0);
    const ResourceId rhsId = rhs.attrRef->id ? rhs.attrRef->id.value() : ResourceId(0);
    if (lhsId < rhsId) {
        return true;
    } else if (lhsId > rhsId) {
        return false;
    } else {
        return lhs.attrRef->name.value() < rhs.attrRef->name.value();
    }
}

void JavaClassGenerator::writeStyleableEntryForClass(ClassDefinitionWriter* outClassDef,
                                                     AnnotationProcessor* processor,
                                                     const StringPiece16& packageNameToGenerate,
                                                     const std::u16string& entryName,
                                                     const Styleable* styleable) {
    const std::string className = transform(entryName);

    // This must be sorted by resource ID.
    std::vector<StyleableAttr> sortedAttributes;
    sortedAttributes.reserve(styleable->entries.size());
    for (const auto& attr : styleable->entries) {
        // If we are not encoding final attributes, the styleable entry may have no ID
        // if we are building a static library.
        assert((!mOptions.useFinal || attr.id) && "no ID set for Styleable entry");
        assert(attr.name && "no name set for Styleable entry");

        StyleableAttr styleableAttr = {};
        styleableAttr.attrRef = &attr;
        styleableAttr.fieldName = transformNestedAttr(attr.name.value(), className,
                                                      packageNameToGenerate);

        Reference mangledReference;
        mangledReference.id = attr.id;
        mangledReference.name = attr.name;
        if (mangledReference.name.value().package.empty()) {
            mangledReference.name.value().package = mContext->getCompilationPackage();
        }

        if (Maybe<ResourceName> mangledName =
                mContext->getNameMangler()->mangleName(mangledReference.name.value())) {
            mangledReference.name = mangledName;
        }

        const SymbolTable::Symbol* symbol = mContext->getExternalSymbols()->findByReference(
                mangledReference);
        if (symbol) {
            styleableAttr.attribute = symbol->attribute;
        }
        sortedAttributes.push_back(std::move(styleableAttr));
    }
    std::sort(sortedAttributes.begin(), sortedAttributes.end(), lessStyleableAttr);

    const size_t attrCount = sortedAttributes.size();

    if (attrCount > 0) {
        // Build the comment string for the Styleable. It includes details about the
        // child attributes.
        std::stringstream styleableComment;
        if (!styleable->getComment().empty()) {
            styleableComment << styleable->getComment() << "\n";
        } else {
            styleableComment << "Attributes that can be used with a " << className << ".\n";
        }
        styleableComment <<
                "<p>Includes the following attributes:</p>\n"
                "<table>\n"
                "<colgroup align=\"left\" />\n"
                "<colgroup align=\"left\" />\n"
                "<tr><th>Attribute</th><th>Description</th></tr>\n";

        for (const auto& entry : sortedAttributes) {
            const ResourceName& attrName = entry.attrRef->name.value();
            styleableComment << "<tr><td>";
            styleableComment << "<code>{@link #"
                             << entry.fieldName << " "
                             << (!attrName.package.empty()
                                    ? attrName.package : mContext->getCompilationPackage())
                             << ":" << attrName.entry
                             << "}</code>";
            styleableComment << "</td>";

            styleableComment << "<td>";
            if (entry.attribute) {
                styleableComment << entry.attribute->getComment();
            }
            styleableComment << "</td></tr>\n";
        }
        styleableComment << "</table>\n";
        for (const auto& entry : sortedAttributes) {
            styleableComment << "@see #" << entry.fieldName << "\n";
        }
        processor->appendComment(styleableComment.str());
    }

    auto accessorFunc = [](const StyleableAttr& a) -> ResourceId {
        return a.attrRef->id ? a.attrRef->id.value() : ResourceId(0);
    };

    // First we emit the array containing the IDs of each attribute.
    outClassDef->addArrayMember(className, processor,
                                sortedAttributes.begin(),
                                sortedAttributes.end(),
                                accessorFunc);

    // Now we emit the indices into the array.
    for (size_t i = 0; i < attrCount; i++) {
        const StyleableAttr& styleableAttr = sortedAttributes[i];
        const ResourceName& attrName = styleableAttr.attrRef->name.value();

        StringPiece16 packageName = attrName.package;
        if (packageName.empty()) {
            packageName = mContext->getCompilationPackage();
        }

        AnnotationProcessor attrProcessor;

        StringPiece16 comment = styleableAttr.attrRef->getComment();
        if (styleableAttr.attribute && comment.empty()) {
            comment = styleableAttr.attribute->getComment();
        }

        if (!comment.empty()) {
            attrProcessor.appendComment("<p>\n@attr description");
            attrProcessor.appendComment(comment);
        } else {
            std::stringstream defaultComment;
            defaultComment
                    << "<p>This symbol is the offset where the "
                    << "{@link " << packageName << ".R.attr#" << transform(attrName.entry) << "}\n"
                    << "attribute's value can be found in the "
                    << "{@link #" << className << "} array.";
            attrProcessor.appendComment(defaultComment.str());
        }

        attrProcessor.appendNewLine();

        if (styleableAttr.attribute) {
            addAttributeFormatDoc(&attrProcessor, styleableAttr.attribute.get());
            attrProcessor.appendNewLine();
        }

        std::stringstream doclavaName;
        doclavaName << "@attr name " << packageName << ":" << attrName.entry;;
        attrProcessor.appendComment(doclavaName.str());
        outClassDef->addIntMember(sortedAttributes[i].fieldName, &attrProcessor, i);
    }
}

bool JavaClassGenerator::writeEntriesForClass(ClassDefinitionWriter* outClassDef,
                                              const StringPiece16& packageNameToGenerate,
                                              const ResourceTablePackage* package,
                                              const ResourceTableType* type) {
    for (const auto& entry : type->entries) {
        if (skipSymbol(entry->symbolStatus.state)) {
            continue;
        }

        ResourceId id;
        if (package->id && type->id && entry->id) {
            id = ResourceId(package->id.value(), type->id.value(), entry->id.value());
        }

        std::u16string unmangledPackage;
        std::u16string unmangledName = entry->name;
        if (NameMangler::unmangle(&unmangledName, &unmangledPackage)) {
            // The entry name was mangled, and we successfully unmangled it.
            // Check that we want to emit this symbol.
            if (package->name != unmangledPackage) {
                // Skip the entry if it doesn't belong to the package we're writing.
                continue;
            }
        } else if (packageNameToGenerate != package->name) {
            // We are processing a mangled package name,
            // but this is a non-mangled resource.
            continue;
        }

        if (!isValidSymbol(unmangledName)) {
            ResourceNameRef resourceName(packageNameToGenerate, type->type, unmangledName);
            std::stringstream err;
            err << "invalid symbol name '" << resourceName << "'";
            mError = err.str();
            return false;
        }

        // Build the comments and annotations for this entry.

        AnnotationProcessor processor;
        if (entry->symbolStatus.state != SymbolState::kUndefined) {
            processor.appendComment(entry->symbolStatus.comment);
        }

        for (const auto& configValue : entry->values) {
            processor.appendComment(configValue->value->getComment());
        }

        // If this is an Attribute, append the format Javadoc.
        if (!entry->values.empty()) {
            if (Attribute* attr = valueCast<Attribute>(entry->values.front()->value.get())) {
                // We list out the available values for the given attribute.
                addAttributeFormatDoc(&processor, attr);
            }
        }

        if (type->type == ResourceType::kStyleable) {
            assert(!entry->values.empty());
            const Styleable* styleable = static_cast<const Styleable*>(
                    entry->values.front()->value.get());
            writeStyleableEntryForClass(outClassDef, &processor, packageNameToGenerate,
                                        unmangledName, styleable);
        } else {
            outClassDef->addResourceMember(transform(unmangledName), &processor, id);
        }
    }
    return true;
}

bool JavaClassGenerator::generate(const StringPiece16& packageNameToGenerate, std::ostream* out) {
    return generate(packageNameToGenerate, packageNameToGenerate, out);
}

bool JavaClassGenerator::generate(const StringPiece16& packageNameToGenerate,
                                  const StringPiece16& outPackageName, std::ostream* out) {
    generateHeader(outPackageName, out);

    *out << "public final class R {\n";

    for (const auto& package : mTable->packages) {
        for (const auto& type : package->types) {
            if (type->type == ResourceType::kAttrPrivate) {
                continue;
            }

            ClassDefinitionWriterOptions classOptions;
            classOptions.useFinalQualifier = mOptions.useFinal;
            classOptions.forceCreationIfEmpty =
                    (mOptions.types == JavaClassGeneratorOptions::SymbolTypes::kPublic);
            ClassDefinitionWriter classDef(toString(type->type), classOptions);
            bool result = writeEntriesForClass(&classDef, packageNameToGenerate,
                                               package.get(), type.get());
            if (!result) {
                return false;
            }

            if (type->type == ResourceType::kAttr) {
                // Also include private attributes in this same class.
                ResourceTableType* privType = package->findType(ResourceType::kAttrPrivate);
                if (privType) {
                    result = writeEntriesForClass(&classDef, packageNameToGenerate,
                                                  package.get(), privType);
                    if (!result) {
                        return false;
                    }
                }
            }

            AnnotationProcessor processor;
            if (type->type == ResourceType::kStyleable &&
                    mOptions.types == JavaClassGeneratorOptions::SymbolTypes::kPublic) {
                // When generating a public R class, we don't want Styleable to be part of the API.
                // It is only emitted for documentation purposes.
                processor.appendComment("@doconly");
            }
            classDef.writeToStream(out, "  ", &processor);
        }
    }

    *out << "}\n";
    out->flush();
    return true;
}


} // namespace aapt