#include <qpdf/QPDFJob.hh>

#include <qpdf/JSONHandler.hh>
#include <qpdf/QPDFUsage.hh>
#include <qpdf/QTC.hh>
#include <qpdf/QUtil.hh>

#include <cstring>
#include <memory>
#include <sstream>
#include <stdexcept>

static JSON JOB_SCHEMA = JSON::parse(QPDFJob::job_json_schema(1).c_str());

namespace
{
    class Handlers
    {
      public:
        Handlers(bool partial, std::shared_ptr<QPDFJob::Config> c_main);
        void handle(JSON&);

      private:
#include <qpdf/auto_job_json_decl.hh>

        void usage(std::string const& message);
        void initHandlers();

        typedef std::function<void()> bare_handler_t;
        typedef std::function<void(char const*)> param_handler_t;
        typedef std::function<void(JSON)> json_handler_t;

        // The code that calls these methods is automatically generated by generate_auto_job. This
        // describes how we implement what it does. We keep a stack of handlers in json_handlers.
        // The top of the stack is the "current" json handler, initially for the top-level object.
        // Whenever we encounter a scalar, we add a handler using addBare, addParameter, or
        // addChoices. Whenever we encounter a dictionary, we first add the dictionary handlers.
        // Then we walk into the dictionary and, for each key, we register a dict key handler and
        // push it to the stack, then do the same process for the key's value. Then we pop the key
        // handler off the stack. When we encounter an array, we add the array handlers, push an
        // item handler to the stack, call recursively for the array's single item (as this is what
        // is expected in a schema), and pop the item handler. Note that we don't pop dictionary
        // start/end handlers. The dictionary handlers and the key handlers are at the same level in
        // JSONHandler. This logic is subtle and took several tries to get right. It's best
        // understood by carefully understanding the behavior of JSONHandler, the JSON schema, and
        // the code in generate_auto_job.

        void addBare(bare_handler_t);
        void addParameter(param_handler_t);
        void addChoices(char const** choices, bool required, param_handler_t);
        void pushKey(std::string const& key);
        void beginDict(json_handler_t start_fn, bare_handler_t end_fn);
        void beginArray(json_handler_t start_fn, bare_handler_t end_fn);
        void ignoreItem();
        void popHandler();

        bare_handler_t bindBare(void (Handlers::*f)());
        json_handler_t bindJSON(void (Handlers::*f)(JSON));

        void beginUnderOverlay(JSON const& j);

        std::vector<std::shared_ptr<JSONHandler>> json_handlers;
        bool partial;
        JSONHandler* jh{nullptr}; // points to last of json_handlers
        std::shared_ptr<QPDFJob::Config> c_main;
        std::shared_ptr<QPDFJob::CopyAttConfig> c_copy_att;
        std::shared_ptr<QPDFJob::AttConfig> c_att;
        std::shared_ptr<QPDFJob::PagesConfig> c_pages;
        std::shared_ptr<QPDFJob::UOConfig> c_uo;
        std::shared_ptr<QPDFJob::EncConfig> c_enc;
        std::vector<std::string> accumulated_args;
    };
} // namespace

Handlers::Handlers(bool partial, std::shared_ptr<QPDFJob::Config> c_main) :
    partial(partial),
    c_main(c_main)
{
    initHandlers();
}

void
Handlers::usage(std::string const& message)
{
    throw QPDFUsage(message);
}

Handlers::bare_handler_t
Handlers::bindBare(void (Handlers::*f)())
{
    return std::bind(std::mem_fn(f), this);
}

Handlers::json_handler_t
Handlers::bindJSON(void (Handlers::*f)(JSON))
{
    return std::bind(std::mem_fn(f), this, std::placeholders::_1);
}

void
Handlers::initHandlers()
{
    this->json_handlers.emplace_back(std::make_shared<JSONHandler>());
    this->jh = this->json_handlers.back().get();
    jh->addDictHandlers(
        [](std::string const&, JSON) {},
        [this](std::string const&) {
            if (!this->partial) {
                c_main->checkConfiguration();
            }
        });

#include <qpdf/auto_job_json_init.hh>

    // We have `bits` in the CLI but not in the JSON. Reference this variable so it doesn't generate
    // a warning.
    [](char const**) {}(enc_bits_choices);

    if (this->json_handlers.size() != 1) {
        throw std::logic_error("QPDFJob_json: json_handlers size != 1 at end");
    }
}

void
Handlers::addBare(bare_handler_t fn)
{
    jh->addStringHandler([this, fn](std::string const& path, std::string const& parameter) {
        if (!parameter.empty()) {
            QTC::TC("qpdf", "QPDFJob json bare not empty");
            usage(path + ": value must be the empty string");
        } else {
            fn();
        }
    });
}

void
Handlers::addParameter(param_handler_t fn)
{
    jh->addStringHandler(
        [fn](std::string const& path, std::string const& parameter) { fn(parameter.c_str()); });
}

void
Handlers::addChoices(char const** choices, bool required, param_handler_t fn)
{
    jh->addStringHandler(
        [fn, choices, required, this](std::string const& path, std::string const& parameter) {
            char const* p = parameter.c_str();
            bool matches = false;
            if ((!required) && (parameter.empty())) {
                matches = true;
            }
            if (!matches) {
                for (char const** i = choices; *i; ++i) {
                    if (strcmp(*i, p) == 0) {
                        QTC::TC("qpdf", "QPDFJob json choice match");
                        matches = true;
                        break;
                    }
                }
            }
            if (!matches) {
                QTC::TC("qpdf", "QPDFJob json choice mismatch");
                std::ostringstream msg;
                msg << path + ": unexpected value; expected one of ";
                bool first = true;
                for (char const** i = choices; *i; ++i) {
                    if (first) {
                        first = false;
                    } else {
                        msg << ", ";
                    }
                    msg << *i;
                }
                usage(msg.str());
            }
            fn(parameter.c_str());
        });
}

void
Handlers::pushKey(std::string const& key)
{
    auto new_jh = std::make_shared<JSONHandler>();
    this->jh->addDictKeyHandler(key, new_jh);
    this->jh = new_jh.get();
    this->json_handlers.emplace_back(std::move(new_jh));
}

void
Handlers::beginDict(json_handler_t start_fn, bare_handler_t end_fn)
{
    jh->addDictHandlers(
        [start_fn](std::string const&, JSON j) { start_fn(j); },
        [end_fn](std::string const&) { end_fn(); });
}

void
Handlers::beginArray(json_handler_t start_fn, bare_handler_t end_fn)
{
    auto item_jh = std::make_shared<JSONHandler>();
    jh->addArrayHandlers(
        [start_fn](std::string const&, JSON j) { start_fn(j); },
        [end_fn](std::string const&) { end_fn(); },
        item_jh);
    jh->addFallbackHandler(item_jh);
    this->jh = item_jh.get();
    this->json_handlers.emplace_back(std::move(item_jh));
}

void
Handlers::ignoreItem()
{
    jh->addAnyHandler([](std::string const&, JSON) {});
}

void
Handlers::popHandler()
{
    this->json_handlers.pop_back();
    this->jh = this->json_handlers.back().get();
}

void
Handlers::handle(JSON& j)
{
    this->json_handlers.back()->handle(".", j);
}

void
Handlers::beginUnderOverlay(JSON const& j)
{
    // File has to be processed before items, so handle it here.
    std::string file;
    if (!j.getDictItem("file").getString(file)) {
        QTC::TC("qpdf", "QPDFJob json over/under no file");
        usage("file is required in underlay/overlay specification");
    }
    c_uo->file(file);
}

void
Handlers::setupInputFile()
{
    addParameter([this](char const* p) { c_main->inputFile(p); });
}

void
Handlers::setupPassword()
{
    addParameter([this](char const* p) { c_main->password(p); });
}

void
Handlers::setupEmpty()
{
    addBare([this]() { c_main->emptyInput(); });
}

void
Handlers::setupOutputFile()
{
    addParameter([this](char const* p) { c_main->outputFile(p); });
}

void
Handlers::setupReplaceInput()
{
    addBare([this]() { c_main->replaceInput(); });
}

void
Handlers::beginEncrypt(JSON j)
{
    // This method is only called if the overall JSON structure matches the schema, so we already
    // know that keys that are present have the right types.
    int key_len = 0;
    std::string user_password;
    std::string owner_password;
    bool user_password_seen = false;
    bool owner_password_seen = false;
    j.forEachDictItem([&](std::string const& key, JSON value) {
        if ((key == "40bit") || (key == "128bit") || (key == "256bit")) {
            if (key_len != 0) {
                QTC::TC("qpdf", "QPDFJob json encrypt duplicate key length");
                usage("exactly one of 40bit, 128bit, or 256bit must be given");
            }
            key_len = QUtil::string_to_int(key.c_str());
        } else if (key == "userPassword") {
            user_password_seen = value.getString(user_password);
        } else if (key == "ownerPassword") {
            owner_password_seen = value.getString(owner_password);
        }
    });
    if (key_len == 0) {
        QTC::TC("qpdf", "QPDFJob json encrypt no key length");
        usage(
            "exactly one of 40bit, 128bit, or 256bit must be given; an empty dictionary may be "
            "supplied for one of them to set the key length without imposing any restrictions");
    }
    if (!(user_password_seen && owner_password_seen)) {
        QTC::TC("qpdf", "QPDFJob json encrypt missing password");
        usage(
            "the user and owner password are both required; use the empty string for the user "
            "password if you don't want a password");
    }
    this->c_enc = c_main->encrypt(key_len, user_password, owner_password);
}

void
Handlers::endEncrypt()
{
    this->c_enc->endEncrypt();
    this->c_enc = nullptr;
}

void
Handlers::setupEncryptUserPassword()
{
    // handled in beginEncrypt
    ignoreItem();
}

void
Handlers::setupEncryptOwnerPassword()
{
    // handled in beginEncrypt
    ignoreItem();
}

void
Handlers::beginEncrypt40bit(JSON)
{
    // nothing needed
}

void
Handlers::endEncrypt40bit()
{
    // nothing needed
}

void
Handlers::beginEncrypt128bit(JSON)
{
    // nothing needed
}

void
Handlers::endEncrypt128bit()
{
    // nothing needed
}

void
Handlers::beginEncrypt256bit(JSON)
{
    // nothing needed
}

void
Handlers::endEncrypt256bit()
{
    // nothing needed
}

void
Handlers::beginJsonKeyArray(JSON)
{
    // nothing needed
}

void
Handlers::endJsonKeyArray()
{
    // nothing needed
}

void
Handlers::beginJsonObjectArray(JSON)
{
    // nothing needed
}

void
Handlers::endJsonObjectArray()
{
    // nothing needed
}

void
Handlers::beginAddAttachmentArray(JSON)
{
    // nothing needed
}

void
Handlers::endAddAttachmentArray()
{
    // nothing needed
}

void
Handlers::beginAddAttachment(JSON)
{
    this->c_att = c_main->addAttachment();
}

void
Handlers::endAddAttachment()
{
    this->c_att->endAddAttachment();
    this->c_att = nullptr;
}

void
Handlers::setupAddAttachmentFile()
{
    addParameter([this](char const* p) { c_att->file(p); });
}

void
Handlers::beginRemoveAttachmentArray(JSON)
{
    // nothing needed
}

void
Handlers::endRemoveAttachmentArray()
{
    // nothing needed
}
void
Handlers::beginCopyAttachmentsFromArray(JSON)
{
    // nothing needed
}

void
Handlers::endCopyAttachmentsFromArray()
{
    // nothing needed
}

void
Handlers::beginCopyAttachmentsFrom(JSON)
{
    this->c_copy_att = c_main->copyAttachmentsFrom();
}

void
Handlers::endCopyAttachmentsFrom()
{
    this->c_copy_att->endCopyAttachmentsFrom();
    this->c_copy_att = nullptr;
}

void
Handlers::setupCopyAttachmentsFromFile()
{
    addParameter([this](char const* p) { c_copy_att->file(p); });
}

void
Handlers::setupCopyAttachmentsFromPassword()
{
    addParameter([this](char const* p) { c_copy_att->password(p); });
}

void
Handlers::beginPagesArray(JSON)
{
    this->c_pages = c_main->pages();
}

void
Handlers::endPagesArray()
{
    c_pages->endPages();
    c_pages = nullptr;
}

void
Handlers::beginPages(JSON j)
{
    std::string file;
    if (!j.getDictItem("file").getString(file)) {
        QTC::TC("qpdf", "QPDFJob json pages no file");
        usage("file is required in page specification");
    }
    c_pages->file(file);
}

void
Handlers::endPages()
{
    // nothing needed
}

void
Handlers::setupPagesFile()
{
    // This is handled in beginPages since file() has to be called first.
    ignoreItem();
}

void
Handlers::setupPagesPassword()
{
    addParameter([this](char const* p) { c_pages->password(p); });
}

void
Handlers::beginOverlayArray(JSON)
{
    // nothing needed
}

void
Handlers::endOverlayArray()
{
    // nothing needed
}

void
Handlers::beginOverlay(JSON j)
{
    this->c_uo = c_main->overlay();
    beginUnderOverlay(j);
}

void
Handlers::endOverlay()
{
    c_uo->endUnderlayOverlay();
    c_uo = nullptr;
}

void
Handlers::setupOverlayFile()
{
    // This is handled in beginOverlay since file() has to be called first.
    ignoreItem();
}

void
Handlers::setupOverlayPassword()
{
    addParameter([this](char const* p) { c_uo->password(p); });
}

void
Handlers::beginUnderlayArray(JSON)
{
    // nothing needed
}

void
Handlers::endUnderlayArray()
{
    // nothing needed
}

void
Handlers::beginUnderlay(JSON j)
{
    this->c_uo = c_main->underlay();
    beginUnderOverlay(j);
}

void
Handlers::endUnderlay()
{
    c_uo->endUnderlayOverlay();
    c_uo = nullptr;
}

void
Handlers::setupUnderlayFile()
{
    // This is handled in beginUnderlay since file() has to be called first.
    ignoreItem();
}

void
Handlers::setupUnderlayPassword()
{
    addParameter([this](char const* p) { c_uo->password(p); });
}

void
Handlers::setupSetPageLabels()
{
    accumulated_args.clear();
    addParameter([this](char const* p) { accumulated_args.push_back(p); });
}

void
Handlers::endSetPageLabelsArray()
{
    c_main->setPageLabels(accumulated_args);
    accumulated_args.clear();
}

void
Handlers::beginSetPageLabelsArray(JSON)
{
    // nothing needed
}

void
QPDFJob::initializeFromJson(std::string const& json, bool partial)
{
    std::list<std::string> errors;
    JSON j = JSON::parse(json);
    if (!j.checkSchema(JOB_SCHEMA, JSON::f_optional, errors)) {
        std::ostringstream msg;
        msg << m->message_prefix << ": job json has errors:";
        for (auto const& error: errors) {
            msg << std::endl << "  " << error;
        }
        throw std::runtime_error(msg.str());
    }

    Handlers(partial, config()).handle(j);
}