//===-- IOChannel.cpp -------------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "Platform.h"
#include "IOChannel.h"

#include <map>

#include "lldb/API/SBCommandInterpreter.h"
#include "lldb/API/SBDebugger.h"
#include "lldb/API/SBError.h"
#include "lldb/API/SBEvent.h"
#include "lldb/API/SBFileSpec.h"
#include "lldb/API/SBHostOS.h"
#include "lldb/API/SBListener.h"
#include "lldb/API/SBStringList.h"

#include <string.h>
#include <limits.h>

using namespace lldb;

typedef std::map<EditLine *, std::string> PromptMap;
const char *g_default_prompt = "(lldb) ";
PromptMap g_prompt_map;

// Printing the following string causes libedit to back up to the beginning of the line & blank it out.
const char undo_prompt_string[4] = { (char) 13, (char) 27, (char) 91, (char) 75};

static const char*
el_prompt(EditLine *el)
{
    PromptMap::const_iterator pos = g_prompt_map.find (el);
    if (pos == g_prompt_map.end())
        return g_default_prompt;
    return pos->second.c_str();
}

const char *
IOChannel::GetPrompt ()
{
    PromptMap::const_iterator pos = g_prompt_map.find (m_edit_line);
    if (pos == g_prompt_map.end())
        return g_default_prompt;
    return pos->second.c_str();
}

bool
IOChannel::EditLineHasCharacters ()
{
    const LineInfo *line_info  = el_line(m_edit_line);
    if (line_info)
    {
        // Sometimes we get called after the user has submitted the line, but before editline has
        // cleared the buffer.  In that case the cursor will be pointing at the newline.  That's
        // equivalent to having no characters on the line, since it has already been submitted.
        if (*line_info->cursor == '\n')
            return false;
        else
            return line_info->cursor != line_info->buffer;
    }
    else
        return false;
}


void
IOChannel::EraseCharsBeforeCursor ()
{
    const LineInfo *line_info  = el_line(m_edit_line);
    if (line_info != NULL)
        el_deletestr(m_edit_line, line_info->cursor - line_info->buffer);
}

unsigned char
IOChannel::ElCompletionFn (EditLine *e, int ch)
{
    IOChannel *io_channel;
    if (el_get(e, EL_CLIENTDATA, &io_channel) == 0)
    {
        return io_channel->HandleCompletion (e, ch);
    }
    else
    {
        return CC_ERROR;
    }
}

void
IOChannel::ElResize()
{
    el_resize(m_edit_line);
}

unsigned char
IOChannel::HandleCompletion (EditLine *e, int ch)
{
    assert (e == m_edit_line);

    const LineInfo *line_info  = el_line(m_edit_line);
    SBStringList completions;
    int page_size = 40;

    int num_completions = m_driver->GetDebugger().GetCommandInterpreter().HandleCompletion (line_info->buffer,
                                                                                            line_info->cursor,
                                                                                            line_info->lastchar,
                                                                                            0,
                                                                                            -1,
                                                                                            completions);
    
    if (num_completions == -1)
    {
        el_insertstr (m_edit_line, m_completion_key);
        return CC_REDISPLAY;
    }
    else if (num_completions == -2)
    {
        el_deletestr (m_edit_line, line_info->cursor - line_info->buffer);
        el_insertstr (m_edit_line, completions.GetStringAtIndex(0));
        return CC_REDISPLAY;
    }

    // If we get a longer match display that first.
    const char *completion_str = completions.GetStringAtIndex(0);
    if (completion_str != NULL && *completion_str != '\0')
    {
        el_insertstr (m_edit_line, completion_str);
        return CC_REDISPLAY;
    }

    if (num_completions > 1)
    {
        const char *comment = "\nAvailable completions:";

        int num_elements = num_completions + 1;
        OutWrite(comment,  strlen (comment), NO_ASYNC);
        if (num_completions < page_size)
        {
            for (int i = 1; i < num_elements; i++)
            {
                completion_str = completions.GetStringAtIndex(i);
                OutWrite("\n\t", 2, NO_ASYNC);
                OutWrite(completion_str, strlen (completion_str), NO_ASYNC);
            }
            OutWrite ("\n", 1, NO_ASYNC);
        }
        else
        {
            int cur_pos = 1;
            char reply;
            int got_char;
            while (cur_pos < num_elements)
            {
                int endpoint = cur_pos + page_size;
                if (endpoint > num_elements)
                    endpoint = num_elements;
                for (; cur_pos < endpoint; cur_pos++)
                {
                    completion_str = completions.GetStringAtIndex(cur_pos);
                    OutWrite("\n\t", 2, NO_ASYNC);
                    OutWrite(completion_str, strlen (completion_str), NO_ASYNC);
                }

                if (cur_pos >= num_elements)
                {
                    OutWrite("\n", 1, NO_ASYNC);
                    break;
                }

                OutWrite("\nMore (Y/n/a): ", strlen ("\nMore (Y/n/a): "), NO_ASYNC);
                reply = 'n';
                got_char = el_getc(m_edit_line, &reply);
                if (got_char == -1 || reply == 'n')
                    break;
                if (reply == 'a')
                    page_size = num_elements - cur_pos;
            }
        }

    }

    if (num_completions == 0)
        return CC_REFRESH_BEEP;
    else
        return CC_REDISPLAY;
}

IOChannel::IOChannel
(
    FILE *editline_in,
    FILE *editline_out,
    FILE *out,  
    FILE *err,
    Driver *driver
) :
    SBBroadcaster ("IOChannel"),
    m_output_mutex (),
    m_enter_elgets_time (),
    m_driver (driver),
    m_read_thread (LLDB_INVALID_HOST_THREAD),
    m_read_thread_should_exit (false),
    m_out_file (out),
    m_err_file (err),
    m_editline_out (editline_out),
    m_command_queue (),
    m_completion_key ("\t"),
    m_edit_line (::el_init (SBHostOS::GetProgramFileSpec().GetFilename(), editline_in, editline_out,  editline_out)),
    m_history (history_init()),
    m_history_event(),
    m_getting_command (false),
    m_expecting_prompt (false),
    m_prompt_str (),
    m_refresh_request_pending (false)
{
    assert (m_edit_line);
    el_set (m_edit_line, EL_PROMPT, el_prompt);
    el_set (m_edit_line, EL_EDITOR, "emacs");
    el_set (m_edit_line, EL_HIST, history, m_history);
    el_set (m_edit_line, EL_ADDFN, "lldb_complete", "LLDB completion function", IOChannel::ElCompletionFn);
    el_set (m_edit_line, EL_BIND, m_completion_key, "lldb_complete", NULL);
    el_set (m_edit_line, EL_BIND, "^r", "em-inc-search-prev", NULL);  // Cycle through backwards search, entering string
    el_set (m_edit_line, EL_BIND, "^w", "ed-delete-prev-word", NULL); // Delete previous word, behave like bash does.
    el_set (m_edit_line, EL_BIND, "\033[3~", "ed-delete-next-char", NULL); // Fix the delete key.
    el_set (m_edit_line, EL_CLIENTDATA, this);

    // Source $PWD/.editrc then $HOME/.editrc
    el_source (m_edit_line, NULL);

    assert (m_history);
    history (m_history, &m_history_event, H_SETSIZE, 800);
    history (m_history, &m_history_event, H_SETUNIQUE, 1);
    // Load history
    HistorySaveLoad (false);

    // Initialize time that ::el_gets was last called.
    m_enter_elgets_time.tv_sec = 0;
    m_enter_elgets_time.tv_usec = 0;

    // set the initial state to non flushed
    m_output_flushed = false;
}

IOChannel::~IOChannel ()
{
    // Save history
    HistorySaveLoad (true);

    if (m_history != NULL)
    {
        ::history_end (m_history);
        m_history = NULL;
    }

    if (m_edit_line != NULL)
    {
        ::el_end (m_edit_line);
        m_edit_line = NULL;
    }
}

void
IOChannel::HistorySaveLoad (bool save)
{
    if (m_history != NULL)
    {
        char history_path[PATH_MAX];
        ::snprintf (history_path, sizeof(history_path), "~/.%s-history", SBHostOS::GetProgramFileSpec().GetFilename());
        if ((size_t)SBFileSpec::ResolvePath (history_path, history_path, sizeof(history_path)) < sizeof(history_path) - 1)
        {
            const char *path_ptr = history_path;
            if (save)
                ::history (m_history, &m_history_event, H_SAVE, path_ptr);
            else
                ::history (m_history, &m_history_event, H_LOAD, path_ptr);
        }
    }
}

void
IOChannel::LibeditOutputBytesReceived (void *baton, const void *src, size_t src_len)
{
    IOChannel *io_channel = (IOChannel *) baton;
    std::lock_guard<std::recursive_mutex> locker(io_channel->m_output_mutex);
    const char *bytes = (const char *) src;

    bool flush = false;

    // See if we have a 'flush' synchronization point in there.
    // this is performed from 'fputc ('\0', m_editline_out);' in LibeditGetInput()
    if (src_len > 0 && bytes[src_len-1] == '\0')
    {
        src_len--;
        flush = true;
    }

    if (io_channel->IsGettingCommand() && io_channel->m_expecting_prompt)
    {
        io_channel->m_prompt_str.append (bytes, src_len);
        // Log this to make sure the prompt is really what you think it is.
        if (io_channel->m_prompt_str.find (el_prompt(io_channel->m_edit_line)) == 0)
        {
            io_channel->m_expecting_prompt = false;
            io_channel->m_refresh_request_pending = false;
            io_channel->OutWrite (io_channel->m_prompt_str.c_str(), 
                                  io_channel->m_prompt_str.size(), NO_ASYNC);
            io_channel->m_prompt_str.clear();
        }
    }
    else
    {
        if (io_channel->m_prompt_str.size() > 0)
            io_channel->m_prompt_str.clear();
        std::string tmp_str (bytes, src_len);
        if (tmp_str.find (el_prompt (io_channel->m_edit_line)) == 0)
            io_channel->m_refresh_request_pending = false;
        io_channel->OutWrite (bytes, src_len, NO_ASYNC);
    }

#if !defined (_MSC_VER)
    if (flush)
    {
        io_channel->m_output_flushed = true;
        io_channel->m_output_cond.notify_all();
    }
#endif

}

IOChannel::LibeditGetInputResult
IOChannel::LibeditGetInput (std::string &new_line)
{
    IOChannel::LibeditGetInputResult retval = IOChannel::eLibeditGetInputResultUnknown;
    if (m_edit_line != NULL)
    {
        int line_len = 0;

        // Set boolean indicating whether or not el_gets is trying to get input (i.e. whether or not to attempt
        // to refresh the prompt after writing data).
        SetGettingCommand (true);
        m_expecting_prompt = true;

        // Call el_gets to prompt the user and read the user's input.
        const char *line = ::el_gets (m_edit_line, &line_len);

#if !defined (_MSC_VER)
        // Force the piped output from el_gets to finish processing.
        // el_gets does an fflush internally, which is not sufficient here; it only
        // writes the data into m_editline_out, but doesn't affect whether our worker
        // thread will read that data yet. So we block here manually.
        {
            std::lock_guard<std::recursive_mutex> locker(m_output_mutex);
            m_output_flushed = false;

            // Write a synchronization point into the stream, so we can guarantee
            // LibeditOutputBytesReceived has processed everything up till that mark.
            fputc ('\0', m_editline_out);

            while (!m_output_flushed)
            {
                // wait until the condition variable is signaled
                m_output_cond.wait(m_output_mutex);
            }
        }
#endif

        // Re-set the boolean indicating whether or not el_gets is trying to get input.
        SetGettingCommand (false);

        if (line)
        {
            retval = IOChannel::eLibeditGetInputValid;
            // strip any newlines off the end of the string...
            while (line_len > 0 && (line[line_len - 1] == '\n' || line[line_len - 1] == '\r'))
                --line_len;
            if (line_len > 0)
            {
                ::history (m_history, &m_history_event, H_ENTER, line);
                new_line.assign (line, line_len);   // Omit the newline
            }
            else
            {
                retval = IOChannel::eLibeditGetInputEmpty;
                // Someone just hit ENTER, return the empty string
                new_line.clear();
            }
            // Return true to indicate success even if a string is empty
            return retval;
        }
        else
        {
            retval = (line_len == 0 ? IOChannel::eLibeditGetInputEOF : IOChannel::eLibeditGetInputResultError);
        }
    }
    // Return false to indicate failure. This can happen when the file handle
    // is closed (EOF).
    new_line.clear();
    return retval;
}

thread_result_t
IOChannel::IOReadThread (void *ptr)
{
    IOChannel *myself = static_cast<IOChannel *> (ptr);
    myself->Run();
    return NULL;
}

void
IOChannel::Run ()
{
    SBListener listener("IOChannel::Run");
    std::string new_line;

    SBBroadcaster interpreter_broadcaster (m_driver->GetDebugger().GetCommandInterpreter().GetBroadcaster());
    listener.StartListeningForEvents (interpreter_broadcaster,
                                      SBCommandInterpreter::eBroadcastBitResetPrompt |
                                      SBCommandInterpreter::eBroadcastBitThreadShouldExit |
                                      SBCommandInterpreter::eBroadcastBitQuitCommandReceived);

    listener.StartListeningForEvents (*this,
                                      IOChannel::eBroadcastBitThreadShouldExit);

    listener.StartListeningForEvents (*m_driver,
                                      Driver::eBroadcastBitReadyForInput |
                                      Driver::eBroadcastBitThreadShouldExit);

    // Let anyone know that the IO channel is up and listening and ready for events
    BroadcastEventByType (eBroadcastBitThreadDidStart);
    bool done = false;
    while (!done)
    {
        SBEvent event;

        listener.WaitForEvent (UINT32_MAX, event);
        if (!event.IsValid())
            continue;

        const uint32_t event_type = event.GetType();

        if (event.GetBroadcaster().IsValid())
        {
            if (event.BroadcasterMatchesPtr (m_driver))
            {
                if (event_type & Driver::eBroadcastBitReadyForInput)
                {
                    std::string line;

                    if (CommandQueueIsEmpty())
                    {
                        IOChannel::LibeditGetInputResult getline_result = LibeditGetInput(line);
                        if (getline_result == IOChannel::eLibeditGetInputEOF)
                        {
                            // EOF occurred
                            // pretend that a quit was typed so the user gets a potential
                            // chance to confirm
                            line.assign("quit");
                        }
                        else if (getline_result == IOChannel::eLibeditGetInputResultError || getline_result == IOChannel::eLibeditGetInputResultUnknown)
                        {
                            // some random error occurred, exit and don't ask because the state might be corrupt
                            done = true;
                            continue;
                        }
                    }
                    else
                    {
                        GetCommandFromQueue (line);
                    }

                    // TO BE DONE: FIGURE OUT WHICH COMMANDS SHOULD NOT BE REPEATED IF USER PRESSES PLAIN 'RETURN'
                    // AND TAKE CARE OF THAT HERE.

                    SBEvent line_event(IOChannel::eBroadcastBitHasUserInput,
                             line.c_str(),
                             line.size());
                    BroadcastEvent (line_event);
                }
                else if (event_type & Driver::eBroadcastBitThreadShouldExit)
                {
                    done = true;
                    continue;
                }
            }
            else if (event.BroadcasterMatchesRef (interpreter_broadcaster))
            {
                switch (event_type)
                {
                case SBCommandInterpreter::eBroadcastBitResetPrompt:
                    {
                        const char *new_prompt = SBEvent::GetCStringFromEvent (event);
                        if (new_prompt)
                            g_prompt_map[m_edit_line] = new_prompt;
                    }
                    break;

                case SBCommandInterpreter::eBroadcastBitThreadShouldExit:
                case SBCommandInterpreter::eBroadcastBitQuitCommandReceived:
                    done = true;
                    break;
                }
            }
            else if (event.BroadcasterMatchesPtr (this))
            {
                if (event_type & IOChannel::eBroadcastBitThreadShouldExit)
                {
                    done = true;
                    continue;
                }
            }
        }
    }
    BroadcastEventByType (IOChannel::eBroadcastBitThreadDidExit);
    m_driver = NULL;
    m_read_thread = 0;
}

bool
IOChannel::Start ()
{
    if (IS_VALID_LLDB_HOST_THREAD(m_read_thread))
        return true;

    m_read_thread = SBHostOS::ThreadCreate("<lldb.driver.commandline_io>", (lldb::thread_func_t) IOChannel::IOReadThread, this, NULL);

    return (IS_VALID_LLDB_HOST_THREAD(m_read_thread));
}

bool
IOChannel::Stop ()
{
    if (!IS_VALID_LLDB_HOST_THREAD(m_read_thread))
        return true;

    BroadcastEventByType (eBroadcastBitThreadShouldExit);

    // Don't call Host::ThreadCancel since el_gets won't respond to this
    // function call -- the thread will just die and all local variables in
    // IOChannel::Run() won't get destructed down which is bad since there is
    // a local listener holding onto broadcasters... To ensure proper shutdown,
    // a ^D (control-D) sequence (0x04) should be written to other end of the
    // the "in" file handle that was passed into the contructor as closing the
    // file handle doesn't seem to make el_gets() exit....
    return SBHostOS::ThreadJoin (m_read_thread, NULL, NULL);
}

void
IOChannel::RefreshPrompt ()
{
    // If we are not in the middle of getting input from the user, there is no need to 
    // refresh the prompt.
    std::lock_guard<std::recursive_mutex> locker(m_output_mutex);
    if (! IsGettingCommand())
        return;

    // If we haven't finished writing the prompt, there's no need to refresh it.
    if (m_expecting_prompt)
        return;

    if (m_refresh_request_pending)
        return;

    ::el_set (m_edit_line, EL_REFRESH);
    m_refresh_request_pending = true;    
}

void
IOChannel::OutWrite (const char *buffer, size_t len, bool asynchronous)
{
    if (len == 0 || buffer == NULL)
        return;

    // We're in the process of exiting -- IOChannel::Run() has already completed
    // and set m_driver to NULL - it is time for us to leave now.  We might not
    // print the final ^D to stdout in this case.  We need to do some re-work on
    // how the I/O streams are managed at some point.
    if (m_driver == NULL)
    {
        return;
    }

    // Use the mutex to make sure OutWrite and ErrWrite do not interfere with each other's output.
    std::lock_guard<std::recursive_mutex> locker(m_output_mutex);
    if (m_driver->EditlineReaderIsTop() && asynchronous)
        ::fwrite (undo_prompt_string, 1, 4, m_out_file);
    ::fwrite (buffer, 1, len, m_out_file);
    if (asynchronous)
        m_driver->GetDebugger().NotifyTopInputReader (eInputReaderAsynchronousOutputWritten);
}

void
IOChannel::ErrWrite (const char *buffer, size_t len, bool asynchronous)
{
    if (len == 0 || buffer == NULL)
        return;

    // Use the mutex to make sure OutWrite and ErrWrite do not interfere with each other's output.
    std::lock_guard<std::recursive_mutex> locker(m_output_mutex);
    if (asynchronous)
        ::fwrite (undo_prompt_string, 1, 4, m_err_file);
    ::fwrite (buffer, 1, len, m_err_file);
    if (asynchronous)
        m_driver->GetDebugger().NotifyTopInputReader (eInputReaderAsynchronousOutputWritten);
}

void
IOChannel::AddCommandToQueue (const char *command)
{
    m_command_queue.push (std::string(command));
}

bool
IOChannel::GetCommandFromQueue (std::string &cmd)
{
    if (m_command_queue.empty())
        return false;
    cmd.swap(m_command_queue.front());
    m_command_queue.pop ();
    return true;
}

int
IOChannel::CommandQueueSize () const
{
    return m_command_queue.size();
}

void
IOChannel::ClearCommandQueue ()
{
    while (!m_command_queue.empty())
        m_command_queue.pop();
}

bool
IOChannel::CommandQueueIsEmpty () const
{
    return m_command_queue.empty();
}

bool
IOChannel::IsGettingCommand () const
{
    return m_getting_command;
}

void
IOChannel::SetGettingCommand (bool new_value)
{
    m_getting_command = new_value;
}