/*
 * Copyright (c) 2019 Stefan Strobel <stefan.strobel@shimatta.net>
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

/**
 * @file    shellmatta.c
 * @brief   Main implementation of the Shellmatta terminal implementation
 * @author  Stefan Strobel <stefan.strobel@shimatta.net>
 */

/**
 * @addtogroup shellmatta_private
 * @{
 */

#include "shellmatta.h"
#include "shellmatta_autocomplete.h"
#include "shellmatta_history.h"
#include "shellmatta_utils.h"
#include "shellmatta_escape.h"
#include <stddef.h>
#include <string.h>
#include <stdarg.h>
#include <stdio.h>

/**
 * @}
 * @addtogroup shellmatta_api
 * @{
 */

/**
 * @brief           initialize the shellmatta terminal and provide all callbacks
 * @param[in,out]   inst                pointer to a shellmatta instance
 * @param[out]      handle              pointer to shellmatta handle -
 *                                      has to be used for all furterh api calls
 * @param[in]       buffer              pointer to the input buffer to use
 * @param[in]       bufferSize          size of the provided input buffer
 * @param[in]       historyBuffer       pointer to the history buffer to use
 *                                      NULL in case of no history buffer
 * @param[in]       historyBufferSize   size of the history buffer
 *                                      0 in case of no history buffer
 * @param[in]       prompt              pointer to prompt string - is printed
 *                                      after each command
 * @param[in]       cmdList             constant command list if no dynamic
 *                                      adding of commands is desired
 * @param[in]       writeFct            function pointer to output function
 */
shellmatta_retCode_t shellmatta_doInit(
        shellmatta_instance_t  *inst,
        shellmatta_handle_t    *handle,
        char                   *buffer,
        uint32_t                bufferSize,
        char                   *historyBuffer,
        uint32_t                historyBufferSize,
        const char             *prompt,
        const shellmatta_cmd_t *cmdList,
        shellmatta_write_t     writeFct)
{
    /** -# check parameters for plausibility  */
    if(     (NULL != inst)
        &&  (NULL != handle)
        &&  (NULL != buffer)
        &&  (0u   != bufferSize)
        &&  (NULL != prompt)
        &&  (NULL != writeFct)
        &&  ((NULL != historyBuffer) || (0u == historyBufferSize)))
    {
        /** -# copy all provided buffers into the shellmatta instance */
        inst->buffer                = buffer;
        inst->bufferSize            = bufferSize;
        inst->inputCount            = 0u;
        inst->lastNewlineIdx        = 0u;
        inst->cursor                = 0u;
        inst->historyBuffer         = historyBuffer;
        inst->historyBufferSize     = historyBufferSize;
        inst->historyStart          = 0u;
        inst->historyEnd            = 0u;
        inst->historyRead           = 0u;
        inst->historyReadUp         = true;
        inst->write                 = writeFct;
        inst->prompt                = prompt;
        inst->echoEnabled           = true;
        inst->dirty                 = false;
        inst->tabCounter            = 0u;
        inst->escapeCounter         = 0u;
        inst->hereLength            = 0u;
        inst->mode                  = SHELLMATTA_MODE_INSERT;
        inst->cmdList               = &helpCmd;
        inst->cmdListIsConst        = false;

        if(NULL != cmdList)
        {
            helpCmd.next = (shellmatta_cmd_t *) cmdList;
            inst->cmdListIsConst = true;
        }

        inst->magic = SHELLMATTA_MAGIC;
        *handle     = (shellmatta_handle_t)inst;

        /** -# print the first prompt */
        utils_terminateInput(inst);
    }

    return SHELLMATTA_OK;
}

/**
 * @brief       adds a command to the command list alphabetically ordered
 * @param[in]   handle  shellmatta instance handle
 * @param[in]   cmd     pointer to the command to add type #shellmatta_cmd_t
 * @return      errorcode   #SHELLMATTA_OK
 *                          #SHELLMATTA_USE_FAULT (param err)
 *                          SHELLMATTA_DUPLICATE
 */
shellmatta_retCode_t shellmatta_addCmd(shellmatta_handle_t handle, shellmatta_cmd_t *cmd)
{
    shellmatta_instance_t   *inst       = (shellmatta_instance_t*)handle;
    shellmatta_cmd_t       *tempCmd;
    shellmatta_cmd_t       **prevCmd;
    bool                    cmdPlaced   = false;
    shellmatta_retCode_t    ret         = SHELLMATTA_OK;
    int                     cmdDiff     = 0;
    int                     aliasDiff   = 0;

    /** -# check parameters for plausibility  */
    if(     (NULL               != inst)
        &&  (SHELLMATTA_MAGIC   == inst->magic)
        &&  (false              == inst->cmdListIsConst))
    {
        tempCmd     = inst->cmdList;
        prevCmd    = &inst->cmdList;
        /** -# register first command as list entry */
        if (NULL == tempCmd)
        {
            inst->cmdList = cmd;
            cmd->next = NULL;
        }
        /** -# append the new command sorted */
        else
        {
            while ((false == cmdPlaced) && (SHELLMATTA_OK == ret))
            {
                cmdDiff     = strcmp(tempCmd->cmd,      cmd->cmd);
                aliasDiff   = strcmp(tempCmd->cmdAlias, cmd->cmdAlias);
                /** -# check for a duplicate command */
                if((0u == cmdDiff) || (0u == aliasDiff))
                {
                    ret = SHELLMATTA_DUPLICATE;
                }
                else if(0 < cmdDiff)
                {
                    cmd->next   = tempCmd;
                    *prevCmd    = cmd;
                    cmdPlaced   = true;
                }
                else if(NULL == tempCmd->next)
                {
                    tempCmd->next = cmd;
                    cmd->next = NULL;
                    cmdPlaced = true;
                }
                else
                {
                    /* nothing to do */
                }
                prevCmd = &(tempCmd->next);
                tempCmd = tempCmd->next;
            }
        }
    }
    else
    {
        ret = SHELLMATTA_USE_FAULT;
    }

    return ret;
}

/**
 * @brief       processes the passed amount of data
 * @param[in]   handle  shellmatta instance handle
 * @param[in]   data    pointer to input data to process
 * @param[in]   size    length of input data to process
 * @return      errorcode   #SHELLMATTA_OK
 *                          #SHELLMATTA_USE_FAULT
 */
shellmatta_retCode_t shellmatta_processData(shellmatta_handle_t     handle,
                                            char                    *data,
                                            uint32_t                 size)
{
    shellmatta_cmd_t        *cmd;
    uint8_t                 cmdExecuted = 0u;
    uint32_t                cmdLen;
    char                    *tempString;
    shellmatta_retCode_t    ret = SHELLMATTA_OK;
    shellmatta_instance_t   *inst = (shellmatta_instance_t*)handle;

    /** -# check parameters for plausibility  */
    if(     (NULL               != inst)
        &&  (SHELLMATTA_MAGIC   == inst->magic))
    {
        /** -# process byte wise */
        for (uint32_t i = 0u; i < size; i++)
        {
            /** -# handle escape sequences */
            if(inst->escapeCounter != 0u)
            {
                escape_handleSequence(inst, *data);
            }
            /** -# ignore newline as first character (to be compatible to
             * terminals sending newline after return */
            else if((0u == inst->inputCount) && ('\n' == *data))
            {
                /* do nothing */
            }
            /** -# handle return as start of processing the command */
            else if ('\r' == *data)
            {
                if(0u == inst->hereLength)
                {
                    /**
                      *  \dot
                      *  digraph heredocParser {
                      *      start -> wait [ label="<< in first line - store delimiter" ];
                      *      wait -> wait [ label="delimiter not detected" ];
                      *      wait -> end [ label="delimiter found - remove all heredoc stuff and send the input to the command" ];
                      *  }
                      *  \enddot */

                    /** -# check for heredoc */
                    tempString = strstr(inst->buffer, "<<");
                    if(NULL != tempString)
                    {
                        /*' -# check if length of heredoc delimiter is valid */
                        if(inst->inputCount > ((uint32_t)(tempString - inst->buffer) + 2u))
                        {
                            inst->hereLength = inst->inputCount - ((uint32_t)(tempString - inst->buffer) + 2u);

                            if(sizeof(inst->hereDelimiter) < inst->hereLength)
                            {
                                inst->write("\r\nHeredoc delimiter too long\r\n", 30u);
                                inst->inputCount = 0u;
                                inst->hereLength    = 0u;
                            }
                            else
                            {
                                /** -# store delimiter and remove it from the input buffer */
                                strncpy(inst->hereDelimiter, &(tempString[2u]), inst->hereLength);

                                inst->inputCount    -= (inst->hereLength + 2u);
                                inst->cursor        = inst->inputCount;
                                inst->dirty = true;
                                utils_insertChars(inst, data, 1);
                                inst->lastNewlineIdx = inst->inputCount;
                            }
                        }
                        else
                        {
                            inst->hereLength    = 0u;
                        }
                    }
                }
                else
                {
                    tempString  = &inst->buffer[inst->lastNewlineIdx];
                    cmdLen      = inst->inputCount - inst->lastNewlineIdx;

                    /** -# skip newline characters before comparison */
                    while(('\n' == *tempString) || ('\r' == *tempString))
                    {
                        tempString ++;
                        cmdLen --;
                    }

                    if(     (inst->hereLength == cmdLen)
                        &&  (0  == strncmp( inst->hereDelimiter,
                                            tempString,
                                            inst->hereLength)))
                    {
                        inst->inputCount = inst->lastNewlineIdx;
                        inst->hereLength = 0u;
                    }
                    else
                    {
                        inst->lastNewlineIdx = inst->inputCount;
                        utils_insertChars(inst, data, 1);
                    }
                }

                if(0u == inst->hereLength)
                {
                    cmd                             = inst->cmdList;
                    inst->buffer[inst->inputCount]  = 0u;

                    /** -# store the current command and reset the history buffer */
                    inst->dirty = true;
                    history_storeCmd(inst);
                    history_reset(inst);

                    /** -# determine the cmd len (chars until first space or \0 is found */
                    cmdLen = 0u;
                    while(      (cmdLen <   inst->inputCount)
                            &&  (' '    !=  inst->buffer[cmdLen])
                            &&  ('\0'   !=  inst->buffer[cmdLen]))
                    {
                        cmdLen ++;
                    }

                    /** -# search for a matching command */
                    while (NULL != cmd)
                    {
                        /** -# compare command string and length */
                        if (    ((0 == strncmp( inst->buffer,
                                                cmd->cmd,
                                                cmdLen))
                                && (cmdLen == strlen(cmd->cmd)))
                            ||  ((0 == strncmp( inst->buffer,
                                                cmd->cmdAlias,
                                                cmdLen))
                                && (cmdLen == strlen(cmd->cmdAlias))))
                        {
                            inst->write("\r\n", 2u);

                            cmdExecuted = 1u;
                            cmd->cmdFct(inst, inst->buffer, inst->inputCount);
                            cmd = NULL;
                        }
                        else
                        {
                            cmd = cmd->next;
                        }
                    }

                    if ((cmdExecuted == 0u) && (inst->inputCount > 0))
                    {
                        inst->buffer[inst->inputCount] = '\0';
                        inst->write("\r\nCommand: ", 11u);
                        inst->write(inst->buffer, inst->inputCount);
                        inst->write(" not found", 10u);
                    }
                    utils_terminateInput(inst);
                }

            }
            /** -# check for tabulator key - auto complete */
            else if('\t' == *data)
            {
                inst->dirty = true;
                autocomplete_run(inst);
            }
            /** -# check for cancel -
             *      terminate current input and print prompt again */
            else if(3 == *data)
            {
                inst->dirty = false;
                history_reset(inst);
                utils_terminateInput(inst);
            }
            /** -# check for backspace */
            else if('\b' == *data)
            {
                inst->dirty = true;
                utils_removeChars(inst, 1u, true);
            }
            /** -# check for delete key */
            else if(0x7eu == *data)
            {
                inst->dirty = true;
                utils_removeChars(inst, 1u, false);
            }
            /** -# check for start of escape sequence */
            else if('\e' == *data)
            {
                inst->escapeCounter = 1u;
            }
            else
            {
                inst->dirty = true;
                utils_insertChars(inst, data, 1);
            }

            /** -# reset tab counter on not a tab */
            if ('\t' != *data)
            {
                inst->tabCounter = 0u;
            }

            data ++;
        }
    }
    else
    {
        ret = SHELLMATTA_USE_FAULT;
    }
    return ret;
}

/**
 * @brief       simple write function to write a datastream to the output of an instance
 * @param[in]   handle  shellmatta instance handle
 * @param[in]   data    data to be written
 * @param[in]   length  amount of data to be written
 * @return
 */
shellmatta_retCode_t shellmatta_write(  shellmatta_handle_t handle,
                                        char                *data,
                                        uint32_t            length)
{
    shellmatta_retCode_t    ret = SHELLMATTA_USE_FAULT;
    shellmatta_instance_t   *inst = (shellmatta_instance_t*)handle;

    /** -# check parameters for plausibility  */
    if(     (NULL               != inst)
        &&  (SHELLMATTA_MAGIC   == inst->magic))
    {
        /** -# pass the data to the write function of the instance  */
        ret = inst->write(data, length);
    }

    return ret;
}

#ifndef SHELLMATTA_STRIP_PRINTF

/**
 * @brief       printf like function to print output to the instances output
 * @param[in]   handle  shellmatta instance handle
 * @param[in]   fmt     format string and parameters
 * @return      errorcode   #SHELLMATTA_OK
 *                          #SHELLMATTA_USE_FAULT   (no valid instance)
 *                          #SHELLMATTA_ERROR       (buffer overflow or format err)
 */
shellmatta_retCode_t shellmatta_printf( shellmatta_handle_t handle,
                                        const char          *fmt,
                                        ...)
{
    char                    outputBuffer[SHELLMATTA_OUTPUT_BUFFER_SIZE];
    va_list                 arg;
    int                     length;
    shellmatta_retCode_t    ret = SHELLMATTA_OK;
    shellmatta_instance_t   *inst = (shellmatta_instance_t*)handle;

    /** -# check parameters for plausibility  */
    if(     (NULL               != inst)
        &&  (SHELLMATTA_MAGIC   == inst->magic))
    {
        /** -# assemble output string and write it  */
        va_start(arg, fmt);
        length = vsnprintf(outputBuffer, SHELLMATTA_OUTPUT_BUFFER_SIZE, fmt, arg);
        va_end(arg);

        if(length < 0)
        {
            ret = SHELLMATTA_ERROR;
        }
        else
        {
            inst->write(outputBuffer, length);
        }
    }
    else
    {
        ret = SHELLMATTA_USE_FAULT;
    }
    return ret;
}
#endif

/** @} */