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#include "languageclientfunctionhint.h"
#include "client.h"

#include <languageserverprotocol/languagefeatures.h>
#include <texteditor/codeassist/assistinterface.h>
#include <texteditor/codeassist/functionhintproposal.h>
#include <texteditor/codeassist/iassistprocessor.h>
#include <texteditor/codeassist/ifunctionhintproposalmodel.h>

using namespace TextEditor;
using namespace LanguageServerProtocol;

namespace LanguageClient {

class FunctionHintProposalModel : public IFunctionHintProposalModel
{
public:
    explicit FunctionHintProposalModel(SignatureHelp signature)
        : m_sigis(signature)
    {}
    void reset() override {}
    int size() const override
    { return m_sigis.signatures().size(); }
    QString text(int index) const override;

    int activeArgument(const QString &/*prefix*/) const override
    { return m_sigis.activeParameter().value_or(0); }

private:
    LanguageServerProtocol::SignatureHelp m_sigis;
};

QString FunctionHintProposalModel::text(int index) const
{
    if (index < 0 || m_sigis.signatures().size() >= index)
        return {};
    return m_sigis.signatures().at(index).label();
}

class FunctionHintProcessor : public IAssistProcessor
{
public:
    explicit FunctionHintProcessor(Client *client) : m_client(client) {}
    IAssistProposal *perform(const AssistInterface *interface) override;
    bool running() override { return m_currentRequest.has_value(); }
    bool needsRestart() const override { return true; }
    void cancel() override;

private:
    void handleSignatureResponse(const SignatureHelpRequest::Response &response);

    QPointer<Client> m_client;
    Utils::optional<MessageId> m_currentRequest;
    int m_pos = -1;
};

IAssistProposal *FunctionHintProcessor::perform(const AssistInterface *interface)
{
    QTC_ASSERT(m_client, return nullptr);
    m_pos = interface->position();
    QTextCursor cursor(interface->textDocument());
    cursor.setPosition(m_pos);
    auto uri = DocumentUri::fromFilePath(interface->filePath());
    SignatureHelpRequest request((TextDocumentPositionParams(TextDocumentIdentifier(uri), Position(cursor))));
    request.setResponseCallback([this](auto response) { this->handleSignatureResponse(response); });
    m_client->sendContent(request);
    m_currentRequest = request.id();
    return nullptr;
}

void FunctionHintProcessor::cancel()
{
    if (running()) {
        m_client->cancelRequest(m_currentRequest.value());
        m_client->removeAssistProcessor(this);
        m_currentRequest.reset();
    }
}

void FunctionHintProcessor::handleSignatureResponse(const SignatureHelpRequest::Response &response)
{
    m_currentRequest.reset();
    if (auto error = response.error())
        m_client->log(error.value());
    m_client->removeAssistProcessor(this);
    const SignatureHelp &signatureHelp = response.result().value().value();
    if (signatureHelp.signatures().isEmpty()) {
        setAsyncProposalAvailable(nullptr);
    } else {
        FunctionHintProposalModelPtr model(new FunctionHintProposalModel(signatureHelp));
        setAsyncProposalAvailable(new FunctionHintProposal(m_pos, model));
    }
}

FunctionHintAssistProvider::FunctionHintAssistProvider(Client *client)
    : CompletionAssistProvider(client)
    , m_client(client)
{}

TextEditor::IAssistProcessor *FunctionHintAssistProvider::createProcessor() const
{
    return new FunctionHintProcessor(m_client);
}

IAssistProvider::RunType FunctionHintAssistProvider::runType() const
{
    return Asynchronous;
}

int FunctionHintAssistProvider::activationCharSequenceLength() const
{
    return m_activationCharSequenceLength;
}

bool FunctionHintAssistProvider::isActivationCharSequence(
    const QString &sequence) const
{
    return Utils::anyOf(m_triggerChars,
                        [sequence](const QString &trigger) { return trigger.endsWith(sequence); });
}

bool FunctionHintAssistProvider::isContinuationChar(const QChar &/*c*/) const
{
    return true;
}

void FunctionHintAssistProvider::setTriggerCharacters(QList<QString> triggerChars)
{
    m_triggerChars = triggerChars;
    for (const QString &trigger : triggerChars) {
        if (trigger.length() > m_activationCharSequenceLength)
            m_activationCharSequenceLength = trigger.length();
    }
}

} // namespace LanguageClient