/*
 
  pow! - the pow!erful package manager

  Copyright (C) 2026 forever2k38
  
  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program. If not, see <https://www.gnu.org/licenses/>.

*/

#include "pow_lua.h"
#include "config.h"
#include "log.h"

#include "archive.h"
#include "stdio.h"
#include "archive_entry.h"
#include "lauxlib.h"
#include "stdlib.h"
#include "unistd.h"
#include "string.h"
#include "sys/sendfile.h"

int pow_lua_extract(lua_State *L) {
  int r;
  ssize_t size;

  struct archive *a;
  struct archive_entry *entry;

  if (!lua_isstring(L, 1)) {
    lua_pushnil(L);
    lua_pushstring(L, "arg 1 must be string (src)");

    return 2;
  }

  if (!lua_isstring(L, 2)) {
    lua_pushnil(L);
    lua_pushstring(L, "arg 2 must be string (dest)");

    return 2;
  }

  const char *filename = lua_tostring(L, 1);
  const char *dest = lua_tostring(L, 2);

  a = archive_read_new();

  archive_read_support_filter_all(a);
  archive_read_support_format_all(a);

  if ((r = archive_read_open_filename(a, filename, 10240))) {
    return 0;
  }

  for (;;) {
    r = archive_read_next_header(a, &entry);

    if (r == ARCHIVE_EOF)
      break;
    if (r < ARCHIVE_OK)
      pow_log_info("warn while unpacking: %s", archive_error_string(a));
    if (r < ARCHIVE_WARN) {
      pow_log_error("error while unpacking: %s", archive_error_string(a));

      lua_pop(L, 1);

      char *error_msg = malloc(256);

      lua_pushnil(L);

      if (!error_msg) {
        lua_pushstring(L, "error while unpacking and failed to malloc to push "
                          "real error message");
        pow_log_error("error while unpacking and failed to push real error message");

        return 2;
      }

      snprintf(error_msg, 256, "error while unpacking: %s",
               archive_error_string(a));

      lua_pushstring(L, error_msg);

      free(error_msg);

      return 2;
    }

    const char *cur = archive_entry_pathname(entry);

    if (cur) {
      size_t need = strlen(dest) + strlen(cur) + 2;

      char *full = malloc(need);

      if (!full) {
        lua_pushnil(L);
        lua_pushstring(L, "failed to malloc entry path\n");

        archive_read_close(a);
        archive_read_free(a);

        return 2;
      }

      snprintf(full, need, "%s/%s", dest, cur);

      archive_entry_set_pathname(entry, full);

      free(full);
    }

    r = archive_read_extract(a, entry, 0);

    if (r < ARCHIVE_WARN) {
      lua_pushnil(L);
      lua_pushfstring(
          L, "failed to extract '%s': %s", archive_entry_pathname(entry),
          archive_error_string(a) ? archive_error_string(a) : "unknown");
      archive_read_close(a);
      archive_read_free(a);

      return 2;
    }
  }

  archive_read_close(a);
  archive_read_free(a);

  lua_pushboolean(L, 1);

  return 1;
}


int pow_lua_install(lua_State *L) {
  if (!lua_isstring(L, 1)) {
    lua_pushnil(L);
    lua_pushstring(L, "arg 1 must be string (src)");

    return 2;
  }

  if (!lua_isstring(L, 2)) {
    lua_pushnil(L);
    lua_pushstring(L, "arg 2 must be string (dest)");

    return 2;
  }

  char *src = strdup(lua_tostring(L, 1));

  if (!src) {
    pow_log_error("failed to strdup source string");

    return 2;
  }

  char *dest = strdup(lua_tostring(L, 2));

  if (!dest) {
    free(src);

    pow_log_error("failed to strdup dest string");

    return 2;
  }

  pow_log_info("installing: %s to %s", src, dest);

  FILE *src_stream = fopen(src, "r");

  if (!src_stream) {
    free(src);
    free(dest);

    pow_log_error("failed to open source file %s while installing", src);

    return 2;
  }

  FILE *dest_stream = fopen(dest, "w");

  if (!dest_stream) {
    free(src);
    free(dest);

    fclose(src_stream);

    pow_log_error("failed to open destination file %s for writing while installing", dest);

    return 2;
  }

  int src_fd = fileno(src_stream);
  int dest_fd = fileno(dest_stream);

  struct stat src_stat = {0};
  int result = fstat(src_fd, &src_stat);

  off_t copied = 0;
  while (result == 0 && copied < src_stat.st_size) {
    ssize_t written = sendfile(dest_fd, src_fd, &copied, SIZE_MAX);
    copied += written;

    if (written == -1) {
      result = -1;
    }
  }

  if (fchmod(dest_fd, src_stat.st_mode) == -1) {
    pow_log_error("failed to set permission bits, expect breakage!");
  }

  return 1;
}

luaL_Reg libpow[] = {{"extract", pow_lua_extract}, {"install", pow_lua_install}, {NULL, NULL}};

int pow_lua_load(lua_State *L, pow_config *cfg) {
  luaL_newlib(L, libpow);

  lua_createtable(L, 0, 1);

  lua_pushstring(L, cfg->makeopts);
  lua_setfield(L, -2, "makeopts");

  lua_setfield(L, -2, "config");

  lua_setglobal(L, "pow");

  return 0;
}