#include "context.hh"

#include "alias_registry.hh"
#include "client.hh"
#include "user_interface.hh"
#include "register_manager.hh"
#include "window.hh"

namespace Kakoune
{

Context::~Context() = default;

Context::Context(InputHandler& input_handler, SelectionList selections,
                 Flags flags, String name)
    : m_input_handler{&input_handler},
      m_selections{std::move(selections)},
      m_flags(flags),
      m_name(std::move(name))
{}

Context::Context(EmptyContextFlag) {}

Buffer& Context::buffer() const
{
    if (not has_buffer())
        throw runtime_error("no buffer in context");
    return const_cast<Buffer&>((*m_selections).buffer());
}

Window& Context::window() const
{
    if (not has_window())
        throw runtime_error("no window in context");
    return *m_window;
}

InputHandler& Context::input_handler() const
{
    if (not has_input_handler())
        throw runtime_error("no input handler in context");
    return *m_input_handler;
}

Client& Context::client() const
{
    if (not has_client())
        throw runtime_error("no client in context");
    return *m_client;
}

UserInterface& Context::ui() const
{
    if (not has_ui())
        throw runtime_error("no user interface in context");
    return client().ui();
}

Scope& Context::scope() const
{
    if (has_window())
        return window();
    if (has_buffer())
        return buffer();
    return GlobalScope::instance();
}

void Context::set_client(Client& client)
{
    kak_assert(not has_client());
    m_client.reset(&client);
}

void Context::set_window(Window& window)
{
    kak_assert(&window.buffer() == &buffer());
    m_window.reset(&window);
}

void Context::print_status(DisplayLine status) const
{
    if (has_client())
        client().print_status(std::move(status));
}

void JumpList::push(SelectionList jump)
{
    if (m_current != m_jumps.end())
        m_jumps.erase(m_current+1, m_jumps.end());
    m_jumps.erase(std::remove(begin(m_jumps), end(m_jumps), jump),
                      end(m_jumps));
    m_jumps.push_back(jump);
    m_current = m_jumps.end();
}

void JumpList::drop()
{
    if (not m_jumps.empty())
        m_jumps.pop_back();
    m_current = m_jumps.end();
}

const SelectionList& JumpList::forward()
{
    if (m_current != m_jumps.end() and
        m_current + 1 != m_jumps.end())
    {
        SelectionList& res = *++m_current;
        res.update();
        return res;
    }
    throw runtime_error("no next jump");
}

const SelectionList& JumpList::backward(const SelectionList& current)
{
    if (m_current != m_jumps.end() and
        *m_current != current)
    {
        push(current);
        SelectionList& res = *--m_current;
        res.update();
        return res;
    }
    if (m_current != m_jumps.begin())
    {
        if (m_current == m_jumps.end())
        {
            push(current);
            --m_current;
            if (m_current == m_jumps.begin())
                throw runtime_error("no previous jump");
        }
        SelectionList& res = *--m_current;
        res.update();
        return res;
    }
    throw runtime_error("no previous jump");
}

void JumpList::forget_buffer(Buffer& buffer)
{
    for (auto it = m_jumps.begin(); it != m_jumps.end();)
    {
        if (&it->buffer() == &buffer)
        {
            if (it < m_current)
                --m_current;
            else if (it == m_current)
                m_current = m_jumps.end()-1;

            it = m_jumps.erase(it);
        }
        else
            ++it;
    }
}

void Context::change_buffer(Buffer& buffer)
{
    if (&buffer == &this->buffer())
        return;

    if (m_edition_level > 0)
       this->buffer().commit_undo_group();

    m_window.reset();
    if (has_client())
        client().change_buffer(buffer);
    else
        m_selections = SelectionList{buffer, Selection{}};
    if (has_input_handler())
        input_handler().reset_normal_mode();
}

SelectionList& Context::selections()
{
    if (not m_selections)
        throw runtime_error("no selections in context");
    (*m_selections).update();
    return *m_selections;
}

SelectionList& Context::selections_write_only()
{
    if (not m_selections)
        throw runtime_error("no selections in context");
    return *m_selections;
}

const SelectionList& Context::selections() const
{
    return const_cast<Context&>(*this).selections();
}

Vector<String> Context::selections_content() const
{
    auto& buf = buffer();
    Vector<String> contents;
    for (auto& sel : selections())
        contents.push_back(buf.string(sel.min(), buf.char_next(sel.max())));
    return contents;
}

void Context::begin_edition()
{
    if (m_edition_level >= 0)
        ++m_edition_level;
}

void Context::end_edition()
{
    if (m_edition_level < 0)
        return;

    kak_assert(m_edition_level != 0);
    if (m_edition_level == 1)
        buffer().commit_undo_group();

    --m_edition_level;
}

StringView Context::main_sel_register_value(StringView reg) const
{
    auto strings = RegisterManager::instance()[reg].values(*this);
    size_t index = m_selections ? (*m_selections).main_index() : 0;
    if (strings.size() <= index)
        index = strings.size() - 1;
   return strings[index];
}

}