/*
 * Wrapper for xlsxio_read library functions.
 *
 * Sample usage:
 *
 *  std::string filename = "sample_file.xlsx";
 *  xlsxioreader xlsxfile = XlsxReader::open_xlsx_file(filename);
 *  if (xlsxfile == NULL) {
 *      printf("cannot open file: '%s'", filename.c_str());
 *      return false;
 *  }
 *  auto sheetNames = XlsxReader::list_sheets(xlsxfile);
 *  for (auto sheetName = sheetNames.begin();
 *       sheetName != sheetNames.end();
 *       ++sheetName) {
 *      printf("reading sheet: %s\n", sheetName->c_str());
 *      xlsxioreadersheet xlsxsheet =
 *              XlsxReader::open_sheet(xlsxfile, *sheetName);
 *      if (xlsxsheet == NULL) {
 *          printf("cannot open sheet: '%s'", sheetName->c_str());
 *          continue;
 *      }
 *      std::string value;
 *      int row_num = 1;
 *      while (XlsxReader::GetNextRow(xlsxsheet)) {
 *          std::string s;
 *          printf("%d:\t", row_num);
 *          while (XlsxReader::GetNextCell(xlsxsheet, s)) {
 *              printf("%s\t", s.c_str());
 *          }
 *          printf("\n");
 *          ++row_num;
 *      }
 *      XlsxReader::close_sheet(xlsxsheet);
 *  }
 *  XlsxReader::close_xlsx_file(xlsxfile);
 *  return true;
 */

#define BUILD_XLSXIO_STATIC
#include <xlsxio_read.h>

#include "DataFuncs.h"
#include "LuaTools.h"
#include "PluginManager.h"

using namespace DFHack;

DFHACK_PLUGIN("xlsxreader");

typedef void* xlsx_file_handle;
typedef void* xlsx_sheet_handle;

// returns NULL on error
xlsx_file_handle open_xlsx_file(std::string filename)
{
    return xlsxioread_open(filename.c_str());
}

void close_xlsx_file(xlsx_file_handle file_handle)
{
    xlsxioread_close((xlsxioreader)file_handle);
}

// returns XLSXIOReaderSheet object or NULL on error
xlsx_sheet_handle open_sheet(xlsx_file_handle file_handle, std::string sheet_name)
{
    if (file_handle == NULL)
        return NULL;
    return xlsxioread_sheet_open((xlsxioreader)file_handle,
                                 sheet_name.c_str(), XLSXIOREAD_SKIP_NONE);
}

void close_sheet(xlsx_sheet_handle sheet_handle)
{
    xlsxioread_sheet_close((xlsxioreadersheet)sheet_handle);
}

static int list_callback(const XLSXIOCHAR* name, void* cbdata)
{
    auto sheetNames = (std::vector<std::string> *)cbdata;
    sheetNames->push_back(name);
    return 0;
}

// start reading the next row of data; must be called before get_next_cell.
// returns false if there is no next row to get.
static bool get_next_row(xlsx_sheet_handle sheet_handle)
{
    return xlsxioread_sheet_next_row((xlsxioreadersheet)sheet_handle) != 0;
}

// fills the value param with the contents of the cell in the next column cell
// in the current row.
// returns false if there are no more cells in this row.
static bool get_next_cell(xlsx_sheet_handle sheet_handle, std::string& value)
{
    char* result;
    if (!xlsxioread_sheet_next_cell_string(
                (xlsxioreadersheet)sheet_handle, &result)) {
        value.clear();
        return false;
    }
    value.assign(result);
    free(result);
    return true;
}

// internal function to factor out handle extraction
static void * get_xlsxreader_handle(lua_State *L)
{
    if (lua_gettop(L) < 1 || lua_isnil(L, 1))
    {
        luaL_error(L, "invalid xlsxreader handle");
    }
    luaL_checktype(L, 1, LUA_TLIGHTUSERDATA);
    return lua_touserdata(L, 1);
}

// takes a file handle and returns a table-list of sheet names
int list_sheets(lua_State *L)
{
    xlsxioreader file_handle = (xlsxioreader)get_xlsxreader_handle(L);
    auto sheetNames = std::vector<std::string>();
    xlsxioread_list_sheets(file_handle, list_callback, &sheetNames);
    Lua::PushVector(L, sheetNames, true);
    return 1;
}

// takes the sheet handle and returns a table-list of strings, or nil if we
// already processed the last row in the file.
int get_row(lua_State *L)
{
    xlsxioreadersheet sheet_handle =
    (xlsxioreadersheet)get_xlsxreader_handle(L);
    bool ok = get_next_row(sheet_handle);
    if (!ok)
    {
        lua_pushnil(L);
    }
    else
    {
        std::string value;
        auto cells = std::vector<std::string>();
        while (get_next_cell(sheet_handle, value))
        {
            cells.push_back(value);
        }
        Lua::PushVector(L, cells, true);
    }

    return 1;
}

DFHACK_PLUGIN_LUA_FUNCTIONS {
    DFHACK_LUA_FUNCTION(open_xlsx_file),
    DFHACK_LUA_FUNCTION(close_xlsx_file),
    DFHACK_LUA_FUNCTION(open_sheet),
    DFHACK_LUA_FUNCTION(close_sheet),
    DFHACK_LUA_END
};

DFHACK_PLUGIN_LUA_COMMANDS{
    DFHACK_LUA_COMMAND(list_sheets),
    DFHACK_LUA_COMMAND(get_row),
    DFHACK_LUA_END
};

DFhackCExport command_result plugin_init(color_ostream &, std::vector<PluginCommand> &)
{
    return CR_OK;
}

DFhackCExport command_result plugin_shutdown(color_ostream &)
{
    return CR_OK;
}