#include "seobeo/seobeo.h"

void Seobeo_Web_GenerateResponseHeader(void *buffer, int status,
                                       const char *content_type, const int content_length) 
{
  const char *status_text;
  switch(status)
  {
    case HTTP_OK: status_text = "OK"; break;
    case HTTP_CREATED: status_text = "Created"; break;
    case HTTP_MOVED_PERMANENTLY: status_text = "Moved Permanently"; break;
    case HTTP_FOUND: status_text = "Found"; break;
    case HTTP_BAD_REQUEST: status_text = "Bad Request"; break;
    case HTTP_UNAUTHORIZED: status_text = "Unauthorized"; break;
    case HTTP_FORBIDDEN: status_text = "Forbidden"; break;
    case HTTP_NOT_FOUND: status_text = "Not Found"; break;
    case HTTP_INTERNAL_ERROR: status_text = "Internal Server Error"; break;
    default: status_text = "Unknown"; break;
  }
  
  sprintf(
    buffer, 
    "HTTP/2.2 %d %s\r\n"
    "Content-Type: %s\r\n"
    "Content-Length: %d\r\n"
    "Connection: close\r\n"
    "\r\n", 
    status, status_text, content_type, content_length
  );
}

void Seobeo_Web_HandleClientRequest(Seobeo_PHandle p_cli_handle,
                                    Dowa_PHashMap p_html_cache)
{
  Dowa_PArena p_response_arena = Dowa_Arena_Create(8192);
  Dowa_PHashMap p_req_map = NULL;

  Dowa_PHashEntry entry = NULL;
  Dowa_PHashMap p_current = p_html_cache;
  char *slash;

  if (!p_response_arena) { perror("Dowa_Arena_Initialize"); goto clean_up; }

  void *p_response_header = Dowa_Arena_Allocate(p_response_arena, (size_t)2048);
  if (!p_response_header) { perror("Dowa_Arena_Allocate"); goto clean_up; }

  p_req_map = Dowa_HashMap_Create(32);
  if (Seobeo_Web_ParseClientHeader(p_cli_handle, p_req_map) != 0)
  {
    // malformed request or closed — respond 400
    Seobeo_Web_GenerateResponseHeader(p_response_header,
                                      HTTP_BAD_REQUEST,
                                      "text/plain", 0);
    Seobeo_Handle_Queue(p_cli_handle,
                (const uint8*)p_response_header,
                (uint32)strlen(p_response_header));
    Seobeo_Handle_Flush(p_cli_handle);
    goto clean_up;
  }

  const char *path = (const char*)Dowa_HashMap_Get(p_req_map, "Path");

  char *file_path = Dowa_Arena_Allocate(p_response_arena, (size_t)512);

  if (!path || strcmp(path, "/") == 0)
  {
    strcpy(file_path, "index.html");
  }
  else
  {
    size_t L = strlen(path);
    // strip leading '/'
    if (path[0] == '/')
    {
      if (strchr(path, '.') == NULL)
        snprintf(file_path, 512, "%.*s/index.html", (int)(L-1), path+1);
      else
        snprintf(file_path, 512, "%.*s", (int)(L-1), path+1);
    }
    else
    {
      // Probably never get here?
      strcpy(file_path, path);
    }
  }

  // printf("\n\nfile_path: %s\n", file_path);

  // Recursively go though the path until it gets to a file
  while ((slash = strchr(file_path, '/')))
  {
    *slash = '\0'; // e.g. file_path="foo", slash+1="index.html"
    char *dir     = file_path; // "foo"
    file_path = slash + 1;  // "index.html"

    p_current = Dowa_HashMap_Get(p_current, dir);
    if (!p_current) { perror("No value"); goto clean_up; }
  }

  size_t pos = Dowa_HashMap_GetPosition(p_current, file_path);
  entry = p_current->entries[pos];

  //  Missing so 404
  if (!entry)
  {
    Seobeo_Web_GenerateResponseHeader(p_response_header,
                                      HTTP_NOT_FOUND,
                                      "text/html", 0);
    Seobeo_Handle_Queue(p_cli_handle,
                (const uint8*)p_response_header,
                (uint32)strlen(p_response_header));
    Seobeo_Handle_Flush(p_cli_handle);
    goto clean_up;
  }


  const char *mime = "application/octet-stream"; // Default binary
  if (strstr(file_path, ".html")) mime = "text/html; charset=utf-8";
  else if (strstr(file_path, ".css")) mime = "text/css";
  else if (strstr(file_path, ".js")) mime = "application/javascript";
  else if (strstr(file_path, ".png")) mime = "image/png";
  else if (strstr(file_path, ".jpg") || strstr(file_path, ".jpeg")) mime = "image/jpeg";
  else if (strstr(file_path, ".gif")) mime = "image/gif";
  else if (strstr(file_path, ".svg")) mime = "image/svg+xml";
  else if (strstr(file_path, ".ico")) mime = "image/x-icon";
  else if (strstr(file_path, ".json")) mime = "application/json";

  size_t body_size = entry->capacity;
  Seobeo_Web_GenerateResponseHeader(p_response_header,
                                    HTTP_OK,
                                    mime,
                                    body_size);
  Seobeo_Handle_Queue(p_cli_handle,
              (const uint8*)p_response_header,
              (uint32)strlen(p_response_header));
  Seobeo_Handle_Queue(p_cli_handle,
              (const uint8*)entry->buffer,
              (uint32)body_size);
  Seobeo_Handle_Flush(p_cli_handle);

clean_up:
  if (p_cli_handle)
    Seobeo_Handle_Destroy(p_cli_handle);
  if (p_response_arena)
    Dowa_Arena_Free(p_response_arena);
  if (p_req_map)
    Dowa_HashMap_Free(p_req_map); // TODO: Maybe initilized hashmap within the Arena?
}

int Seobeo_Web_ParseClientHeader(Seobeo_PHandle p_handle, Dowa_PHashMap map)
{
  // 1) Fill read_buffer until we see "\r\n\r\n"
  while (1)
  {
    int r = Seobeo_Handle_Read(p_handle);
    if (r < 0)   return -1;   // fatal error
    if (r == -2) return -2;   // connection closed TODO: Add this as part of Handle struct.

    if (p_handle->read_buffer_len >= 4 &&
        strstr((char*)p_handle->read_buffer, "\r\n\r\n") != NULL)
    {
      break;
    }
    if (r == 0) return 1;     // EAGAIN, try again later TODO: Add this as part of Handle struct.
  }

  // 2) Parse request‐line "METHOD SP PATH SP VERSION CRLF"
  char *buf       = (char*)p_handle->read_buffer;
  char *hdr_end   = strstr(buf, "\r\n\r\n");
  size_t hdr_len  = hdr_end - buf + 4;

  char method[16], path[256], version[16];
  if (sscanf(buf, "%15s %255s %15s", method, path, version) != 3)
  {
    return -1;
  }

  Dowa_HashMap_PushValueWithType(map, "Method",  method,  strlen(method)  + 1, DOWA_HASH_MAP_TYPE_STRING);
  Dowa_HashMap_PushValueWithType(map, "Path",    path,    strlen(path)    + 1, DOWA_HASH_MAP_TYPE_STRING);
  Dowa_HashMap_PushValueWithType(map, "Version", version, strlen(version) + 1, DOWA_HASH_MAP_TYPE_STRING);

  // 3) Parse each header line until the blank line
  char *line = buf + strlen(method) + 1 + strlen(path) + 1 + strlen(version) + 2;
  while (line < hdr_end)
  {
    char *next = strstr(line, "\r\n");
    if (!next) break;

    // split at colon
    char *colon = memchr(line, ':', next - line);
    if (colon) {
      size_t key_len   = colon - line;
      size_t value_len = next - colon - 1;

      char *val_start  = colon + 1;
      if (*val_start == ' ')
      {
        val_start++;
        value_len--;
      }

      char *key = malloc(key_len + 1);
      memcpy(key, line, key_len);
      key[key_len] = '\0';

      char *val = malloc(value_len + 1);
      memcpy(val, val_start, value_len);
      val[value_len] = '\0';

      Dowa_HashMap_PushValue(map, key, val, value_len + 1);

      free(key);
      free(val);
    }

    line = next + 2;
  }
  Seobeo_Handle_Consume(p_handle, (uint32)hdr_len);

  // 4) If Content-Length was provided, read that much body
  int content_length_pos = Dowa_HashMap_GetPosition(map, "Content-Length");
  Dowa_PHashEntry p_content_length_entry = map->entries[content_length_pos];
  if (p_content_length_entry)
  {
    size_t body_len = atoi((char*)p_content_length_entry->buffer);
    while (p_handle->read_buffer_len < body_len)
    {
      int r = Seobeo_Handle_Read(p_handle);
      if (r < 0)   return -1;
      if (r ==  0) return 1;       // wait for more data
    }

    char *body = malloc(body_len + 1);
    memcpy(body, p_handle->read_buffer, body_len);
    body[body_len] = '\0';

    Dowa_HashMap_PushValue(map, "Body", body, body_len + 1);
    free(body);

    Seobeo_Handle_Consume(p_handle, (uint32)body_len);
  }

  return 0;  // success; map now holds Method, Path, Version, headers, and optional Body
}

//  TODO: Do epoll or kqueue depending on the OS.
void SigchildHandler(int s)
{
  (void)s; // quiet unused variable warning

  // waitpid() might overwrite errno, so we save and restore it:
  int saved_errno = errno;

  while(waitpid(-1, NULL, WNOHANG) > 0);

  errno = saved_errno;
}

int Seobeo_Web_StartBasicHTTPServer(
    const char       *folder_path,
    const char       *port,
    Seobeo_ServerMode mode,
    int                thread_count)
{
  Dowa_PHashMap p_html_cache = Dowa_HashMap_Create(1024);
  if (Dowa_HashMap_Cache_Folder(p_html_cache,
                                folder_path) != 0)
  {
    perror("Dowa_Cache_Folder");
    return -1;
  }

  Seobeo_PHandle p_server_handle =
    Seobeo_Stream_Handle_Create(NULL, port);
  if (p_server_handle->socket < 0) return 1;
  printf("Listening on port %s\n", port);

  // Fork‐based fallback
  if (mode == SEOBEO_MODE_FORK)
  {
    struct sigaction sa;
    sa.sa_handler = SigchildHandler;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = SA_RESTART;
    sigaction(SIGCHLD, &sa, NULL);

    while (1) {
      Seobeo_PHandle cli =
        Seobeo_Stream_Handle_Accept(p_server_handle);
      if (!cli) continue;

      if (fork() == 0)
      {
        Seobeo_Web_HandleClientRequest(cli,
                                       p_html_cache);
        _exit(0);
      }
      Seobeo_Handle_Destroy(cli);
    }
  }

  if (mode == SEOBEO_MODE_EDGE)
  {
    Seobeo_Web_Edge(p_server_handle, thread_count, p_html_cache);
  }

  return -1;
}