#include <gtest/gtest.h>
#include <pdfengine/content_stream.hpp>
#include "../src/qpdf/qpdf_extractor.hpp"
#include <filesystem>
#include <fstream>

using namespace pdfengine;
using namespace pdfengine::qpdf_layer;

#ifndef TEST_CORPUS_DIR
#define TEST_CORPUS_DIR "../../corpus"
#endif

namespace {
std::filesystem::path getCorpusPath(const std::string& subfolder, const std::string& filename) {
    return std::filesystem::path(TEST_CORPUS_DIR) / subfolder / filename;
}

std::vector<uint8_t> readFile(const std::filesystem::path& path) {
    std::ifstream file(path, std::ios::binary | std::ios::ate);
    if (!file.is_open()) return {};
    std::streamsize size = file.tellg();
    file.seekg(0, std::ios::beg);
    std::vector<uint8_t> buffer(size);
    if (file.read(reinterpret_cast<char*>(buffer.data()), size)) {
        return buffer;
    }
    return {};
}
}

class QpdfExtractorTest : public ::testing::Test {
protected:
    QpdfExtractor extractor;
};

TEST_F(QpdfExtractorTest, ExtractFromMemory) {
    auto path = getCorpusPath("basic", "hello_world.pdf");
    auto stream = extractor.extractPageStream(path.string(), 0);
    ASSERT_TRUE(stream.has_value());
    EXPECT_EQ(stream->pageIndex, 0);
    EXPECT_FALSE(stream->compressed); // Or true depending on qpdf, but we only verify success here

    StreamVerification v = verifyContentStream(stream.value());
    EXPECT_TRUE(v.hasBT);
    EXPECT_TRUE(v.hasET);
    EXPECT_TRUE(v.hasTf);
    EXPECT_TRUE(v.hasTj);
}

TEST_F(QpdfExtractorTest, PageOutOfBounds) {
    auto path = getCorpusPath("basic", "hello_world.pdf");
    auto data = readFile(path);
    ASSERT_FALSE(data.empty());

    auto stream = extractor.extractPageStreamFromMemory(data, 1);
    ASSERT_FALSE(stream.has_value());
    EXPECT_EQ(stream.error(), QpdfError::PageOutOfBounds);
    
    stream = extractor.extractPageStreamFromMemory(data, -1);
    ASSERT_FALSE(stream.has_value());
    EXPECT_EQ(stream.error(), QpdfError::PageOutOfBounds);
}

TEST_F(QpdfExtractorTest, CorruptPdf) {
    std::vector<uint8_t> data = {0x00, 0x01, 0x02};
    auto stream = extractor.extractPageStreamFromMemory(data, 0);
    ASSERT_FALSE(stream.has_value());
    EXPECT_EQ(stream.error(), QpdfError::InvalidFormat);
}

TEST_F(QpdfExtractorTest, EmptyContents) {
    // about_blank.pdf usually has an empty page or no text
    auto path = getCorpusPath("basic", "about_blank.pdf");
    auto stream = extractor.extractPageStream(path.string(), 0);
    ASSERT_TRUE(stream.has_value());
    EXPECT_EQ(stream->pageIndex, 0);
    
    StreamVerification v = verifyContentStream(stream.value());
    EXPECT_FALSE(v.hasTj);
}

TEST_F(QpdfExtractorTest, VerifyNoText) {
    // black.pdf or rectangles.pdf has no text, just graphics
    auto path = getCorpusPath("basic", "black.pdf");
    auto stream = extractor.extractPageStream(path.string(), 0);
    ASSERT_TRUE(stream.has_value());
    
    StreamVerification v = verifyContentStream(stream.value());
    EXPECT_FALSE(v.hasBT);
    EXPECT_FALSE(v.hasET);
    EXPECT_FALSE(v.hasTf);
    EXPECT_FALSE(v.hasTj);
}