#include "seobeo/seobeo.h"

// Global folder path for serving files
static char g_folder_path[512] = ".";

int Seobeo_Web_GenerateRequestHeader(void *buffer, const char *host, 
                                     const char *path) 
{
  return sprintf(
    buffer,
    "GET %s HTTP/1.1\r\n"
    "Host: %s\r\n"
    "Connection: close\r\n"
    "accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7\r\n"
    "accept-language: en-GB,en;q=0.9,en-US;q=0.8,ko;q=0.7\r\n"
    "if-modified-since: Sat, 02 Aug 2025 22:51:58 GMT\r\n"
    "if-none-match: W/\"688e968e-5700\"\r\n"
    "priority: u=0, i\r\n"
    "sec-ch-ua: \"Chromium\";v=\"140\", \"Not=A?Brand\";v=\"24\", \"Google Chrome\";v=\"140\"\r\n"
    "sec-ch-ua-mobile: 0\r\n"
    "sec-ch-ua-platform: \"macOS\"\r\n"
    "sec-fetch-dest: document\r\n"
    "sec-fetch-mode: navigate\r\n"
    "sec-fetch-site: none\r\n"
    "sec-fetch-user: 1\r\n"
    "upgrade-insecure-requests: 1\r\n"
    "\r\n",
    path, host
  );
}

// Load file from disk and cache it
static char* Seobeo_Web_LoadFile(const char *file_path, size_t *p_file_size)
{
  char full_path[1024];
  snprintf(full_path, sizeof(full_path), "%s/%s", g_folder_path, file_path);

  FILE *p_file = fopen(full_path, "rb");
  if (!p_file)
    return NULL;

  fseek(p_file, 0, SEEK_END);
  size_t file_size = ftell(p_file);
  fseek(p_file, 0, SEEK_SET);

  char *p_content = (char*)malloc(file_size + 1);
  if (!p_content)
  {
    fclose(p_file);
    return NULL;
  }

  fread(p_content, 1, file_size, p_file);
  p_content[file_size] = '\0';
  fclose(p_file);

  if (p_file_size)
    *p_file_size = file_size;

  return p_content;
}

void Seobeo_Web_Header_Generate(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/1.1 %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_Handle  *p_cli_handle,
                                    Seobeo_Cache_Entry *p_html_cache)
{
  Dowa_Arena *p_request_arena = Dowa_Arena_Create(1*1024*1024); // 1MB for request parsing
  if (!p_request_arena) { perror("Dowa_Arena_Create request"); goto clean_up; }

  Dowa_Arena *p_response_arena = Dowa_Arena_Create(1*1024*1024); // 1MB for response
  if (!p_response_arena) { perror("Dowa_Arena_Create response"); goto clean_up; }

  void *p_response_header = Dowa_Arena_Allocate(p_response_arena, (size_t)1024*5); // 5Kb
  if (!p_response_header) { perror("Dowa_Arena_Allocate"); goto clean_up; }

  // Parse request headers into hashmap using arena
  Seobeo_Request_Entry *p_req_map = NULL;
  if (Seobeo_Web_Header_Parse(p_cli_handle, &p_req_map, p_request_arena) != 0)
  {
    Seobeo_Web_Header_Generate(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;
  }

  // Extract method (GET, POST, etc.)
  void *p_method_kv = Dowa_HashMap_Get_Ptr(p_req_map, "HTTP_Method");
  const char *method = p_method_kv ? ((Seobeo_Request_Entry*)p_method_kv)->value : NULL;

  if (!method)
  {
    Seobeo_Web_Header_Generate(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;
  }

  // --- Handle different HTTP methods ---
  if (strcmp(method, "GET") == 0)
  {
    void *p_kv = Dowa_HashMap_Get_Ptr(p_req_map, "Path");
    const char *path = p_kv ? ((Seobeo_Request_Entry*)p_kv)->value : NULL;
    char *file_path = Dowa_Arena_Allocate(p_response_arena, (size_t)5 * 1024); // 5Kb only for path

    if (!path || strcmp(path, "/") == 0)
    {
      strcpy(file_path, "index.html");
    }
    else
    {
      size_t L = strlen(path);
      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
      {
        strcpy(file_path, path);
      }
    }

    // Check if file is in cache, load if not
    void *p_file_kv = Dowa_HashMap_Get_Ptr(p_html_cache, file_path);
    const char *file_content = NULL;
    size_t body_size = 0;

    if (p_file_kv)
    {
      // File is cached
      file_content = ((Seobeo_Cache_Entry*)p_file_kv)->value;
      body_size = strlen(file_content);
    }
    else
    {
      // Load from disk and cache
      file_content = Seobeo_Web_LoadFile(file_path, &body_size);
      if (file_content)
      {
        Dowa_HashMap_Push(p_html_cache, file_path, file_content);
      }
    }

    if (!file_content)
    {
      Seobeo_Web_Header_Generate(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";
    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";

    printf("File path: %s\nBody Size: %zu\n", file_path, body_size);

    Seobeo_Web_Header_Generate(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*)file_content,
                        (uint32)body_size);
    Seobeo_Handle_Flush(p_cli_handle);
    printf("DONE\n\n\n");
  }
  else if (strcmp(method, "POST") == 0)
  {
    // --- TODO: Add POST logic here ---
    Seobeo_Web_Header_Generate(p_response_header,
                               HTTP_NOT_FOUND,
                               "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);
  }
  else if (strcmp(method, "PUT") == 0)
  {
    // --- TODO: Add PUT logic here ---
    Seobeo_Web_Header_Generate(p_response_header,
                               HTTP_NOT_FOUND,
                               "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);
  }
  else if (strcmp(method, "DELETE") == 0)
  {
    // --- TODO: Add DELETE logic here ---
    Seobeo_Web_Header_Generate(p_response_header,
                               HTTP_NOT_FOUND,
                               "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);
  }
  else
  {
    // Unknown or unsupported method
    Seobeo_Web_Header_Generate(p_response_header,
                               HTTP_FORBIDDEN,
                               "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;

clean_up:
  printf("clean up\n\n");
  if (p_cli_handle)
    Seobeo_Handle_Destroy(p_cli_handle);
  if (p_request_arena)
    Dowa_Arena_Destroy(p_request_arena);
  if (p_response_arena)
    Dowa_Arena_Destroy(p_response_arena);
  return;
}


int Seobeo_Web_Header_Parse(Seobeo_Handle *p_handle, Seobeo_Request_Entry **pp_map, Dowa_Arena *p_arena)
{
  // 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;

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

  // Copy strings to arena and store in hashmap
  char *method_copy = Dowa_Arena_Allocate(p_arena, strlen(method) + 1);
  if (!method_copy) return -1;
  strcpy(method_copy, method);

  char *version_copy = Dowa_Arena_Allocate(p_arena, strlen(version) + 1);
  if (!version_copy) return -1;
  strcpy(version_copy, version);

  Dowa_HashMap_Push_Arena(*pp_map, "HTTP_Method", method_copy, p_arena);
  Dowa_HashMap_Push_Arena(*pp_map, "Version", version_copy, p_arena);

  // 1) Separate raw path and query string
  char *raw_path = path;  
  char *query_start = strchr(raw_path, '?');
  char *query_str   = NULL;
  
  if (query_start)
  {
    *query_start  = '\0';          // now raw_path ends before '?'
    query_str     = query_start + 1;
  }
  
  // push only the clean path
  char *path_copy = Dowa_Arena_Allocate(p_arena, strlen(raw_path) + 1);
  if (!path_copy) return -1;
  strcpy(path_copy, raw_path);
  Dowa_HashMap_Push_Arena(*pp_map, "Path", path_copy, p_arena);
  
  // 2) If there *is* a query, tokenize into the same map with "query_" prefix
  if (query_str && *query_str)
  {
    char *cur = query_str;
    while (cur && *cur)
    {
      char *next_amp = strchr(cur, '&');
      char *pair_end = next_amp ? next_amp : cur + strlen(cur);

      char *eq = memchr(cur, '=', pair_end - cur);
      if (eq)
      {
        size_t key_len = eq - cur;
        size_t val_len = pair_end - (eq + 1);

        char key_buf[256];
        snprintf(key_buf, sizeof(key_buf), "query_%.*s", (int)key_len, cur);

        char *val_copy = Dowa_Arena_Allocate(p_arena, val_len + 1);
        if (!val_copy) return -1;
        memcpy(val_copy, eq + 1, val_len);
        val_copy[val_len] = '\0';

        Dowa_HashMap_Push_Arena(*pp_map, key_buf, val_copy, p_arena);
      }

      cur = next_amp ? next_amp + 1 : NULL;
    }
  }

  // int qp = Dowa_HashMap_Get_Position(map, "QueryParams");
  // Dowa_HashEntry *p_qp_entry = map->entries[qp];
  // printf("query param key: %s\n", p_qp_entry->key);
  // printf("query param value: %s\n",(char *)Dowa_HashMap_Get(p_qp_entry->buffer, "hello"));

  // 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 = Dowa_Arena_Allocate(p_arena, key_len + 1);
      if (!key) return -1;
      memcpy(key, line, key_len);
      key[key_len] = '\0';

      char *val = Dowa_Arena_Allocate(p_arena, value_len + 1);
      if (!val) return -1;
      memcpy(val, val_start, value_len);
      val[value_len] = '\0';

      // Both key and value are arena-allocated, hashmap will use them
      Dowa_HashMap_Push_Arena(*pp_map, key, val, p_arena);
    }

    line = next + 2;
  }

  Seobeo_Handle_Consume(p_handle, (uint32)hdr_len);

  // 4) If Content-Length was provided, read that much body
  void *p_cl_kv = Dowa_HashMap_Get_Ptr(*pp_map, "Content-Length");
  if (p_cl_kv)
  {
    const char *content_length_str = ((Seobeo_Request_Entry*)p_cl_kv)->value;
    size_t body_len = atoi(content_length_str);
    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 = Dowa_Arena_Allocate(p_arena, body_len + 1);
    if (!body) return -1;
    memcpy(body, p_handle->read_buffer, body_len);
    body[body_len] = '\0';

    // Body is arena-allocated
    Dowa_HashMap_Push_Arena(*pp_map, "Body", body, p_arena);

    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_Server_Start(
    const char       *folder_path,
    const char       *port,
    Seobeo_ServerMode mode,
    int                thread_count)
{
  // Store folder path globally
  if (folder_path)
    strncpy(g_folder_path, folder_path, sizeof(g_folder_path) - 1);

  // Initialize empty cache - files will be loaded on-demand
  Seobeo_Cache_Entry *p_html_cache = NULL;

  Seobeo_Handle *p_server_handle =
    Seobeo_Stream_Handle_Server_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)
  {
    printf("FORK MODE\n");
    struct sigaction sa;
    sa.sa_handler = SigchildHandler;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = SA_RESTART;
    sigaction(SIGCHLD, &sa, NULL);

    while (1)
    {
      Seobeo_Handle *p_cli_handle =
        Seobeo_Stream_Handle_Server_Accept(p_server_handle);
      if (!p_cli_handle) continue;

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

  if (mode == SEOBEO_MODE_EDGE)
  {
    printf("EDGE MODE\n");
    Seobeo_Web_Edge(p_server_handle, thread_count, p_html_cache);
  }

  return -1;
}

int Seobeo_Web_Client_Get(const char *host,
                          const char *port,
                          const char *path)
{
  Seobeo_Handle *h = Seobeo_Stream_Handle_Client_Create(host, port, TRUE);
  if (!h || h->socket < 0)
  {
    if (h)
      Seobeo_Handle_Destroy(h);
    return -1;
  }

  Dowa_Arena *p_request_arena = Dowa_Arena_Create(1 * 1024 * 1024);
  if (!p_request_arena) { perror("Dowa_Arena_Create"); return -1; }

  void *p_request_header = Dowa_Arena_Allocate(p_request_arena, 4096);
  if (!p_request_header) { perror("Dowa_Arena_Allocate"); return -1; }

  int request_len = Seobeo_Web_GenerateRequestHeader(p_request_header, host, path);
  // DEBUG
  // printf("request: %s\n", (char *)p_request_header);
  Seobeo_Handle_Queue(h, (uint8 *)p_request_header, (uint32)request_len);
  if (Seobeo_Handle_Flush(h) < 0)
  {
    perror("Seobeo_Handle_Flush");
    Seobeo_Handle_Destroy(h);
    return -1;
  }

  // Response
  size_t cap = 1024*8, used = 0;
  char *p_request_body = Dowa_Arena_Allocate(p_request_arena, cap);
  if (!p_request_body) { Seobeo_Handle_Destroy(h); return -1; }

  while (1)
  {
    int n = Seobeo_Handle_Read(h);
    printf("Size: %d\n", n);
    if (n > 0)
    {
      // TODO: Maybe directly use arena inside of the struct? idk if that is useful or not...
      memcpy(p_request_body + used, h->read_buffer, h->read_buffer_len);
      used += h->read_buffer_len;
      Seobeo_Handle_Consume(h, (uint32)h->read_buffer_len);
    }else if (n == 0)
    {
      // Wait
      continue;
    }else if (n == -2)
    {
      // Debug
      // peer closed; we’ve got everything
      printf("\n\nCLOSED\n\n");
      break;
    }else
    {
      Dowa_Arena_Destroy(p_request_arena);
      Seobeo_Handle_Destroy(h);
      return -1;
    }
  }

  // Debug
  printf("Request body %s", p_request_body);
  Dowa_Arena_Destroy(p_request_arena);
  Seobeo_Handle_Destroy(h);
  return 0;
}