#ifndef HYGATE_H
#define HYGATE_H

#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>

#define DEFAULT_UA "Mozilla/5.0 (X11; Linux x86_64; rv:153.0) Gecko/20100101 Firefox/153.0"
#define DEFAULT_PORT "8080"
#define DEFAULT_ENDPOINT "https://tencent-hy3.hf.space"
#define DEFAULT_MODEL "hy3"
#define MAX_RETRIES 5
#define UPSTREAM_TIMEOUT 300L
#define MAX_CONCURRENT_THREADS 16
#define MAX_BODY_BYTES (5u * 1024u * 1024u)   /* 5 MiB request body cap */

/* ------------------------------------------------------------------ */
/* Dynamic string buffer (always NUL terminated)                       */
/* ------------------------------------------------------------------ */
typedef struct {
  char *buf;
  size_t len;
  size_t cap;
} strbuf;

void sb_init(strbuf *s);
void sb_free(strbuf *s);
int sb_append(strbuf *s, const char *data, size_t n);
int sb_append_str(strbuf *s, const char *str);
void sb_reset(strbuf *s);

/* ------------------------------------------------------------------ */
/* Small utilities                                                     */
/* ------------------------------------------------------------------ */
void generate_uuid(char out[37]);
long fib_delay(int attempt);
int write_all(int fd, const char *buf, size_t n);
int iequals(const char *a, const char *b);

/* ------------------------------------------------------------------ */
/* Tool call representation (parsed from Gradio stream)                 */
/* ------------------------------------------------------------------ */
typedef struct {
  char *id;
  char *type;
  char *name;
  char *arguments;
} tool_call_t;

void free_toolcalls(tool_call_t *tc, int n);

/* Parse a single Gradio SSE data payload: [["content","reasoning",[...]]]
 * Returns 1 on success (caller frees *out_content, *out_reasoning,
 * *out_tc via free_toolcalls). */
int parse_gradio_stream(const char *data_json,
                        char **out_content, char **out_reasoning,
                        tool_call_t **out_tc, int *out_n_tc);

/* ------------------------------------------------------------------ */
/* JSON request <-> Gradio payload translation                          */
/* ------------------------------------------------------------------ */
/* Build the Gradio call payload {"data":[...]} from an OpenAI chat
 * completion request object. Caller frees the result. Returns NULL on
 * malformed input. */
char *build_gradio_payload(void *req_obj, const char *model_default);

/* Build a non-streaming OpenAI completion response JSON string. Caller
 * frees the result. */
char *build_completion_response(const char *id, long created, const char *model,
                                const char *content, const char *reasoning,
                                tool_call_t *tc, int n_tc, int prompt_tokens);


/* Token counting (embedded cl100k_base BPE tokenizer). Counts are
 * deterministic subword counts; the served model (Hunyuan) uses a
 * different tokenizer, so these are an approximation, not exact. */
int tok_count(const char *text, int len);
int tok_count_str(const char *text);

/* Count tokens across an OpenAI request's messages (prompt side). */
int count_messages_tokens(void *req_obj);
/* Count tokens of a generated completion (content + reasoning + tool calls). */
int count_completion_tokens(const char *content, const char *reasoning,
                            tool_call_t *tc, int n_tc);
/* Build a streaming tool-call delta JSON array (first emission: full
 * tool call with index). Caller frees the result. */
char *toolcall_delta_json(tool_call_t *tc, int idx);

/* Build a streaming tool-call argument-delta JSON array (index +
 * function.arguments only). Caller frees the result. */
char *toolcall_delta_argdelta(int idx, const char *delta);

/* ------------------------------------------------------------------ */
/* Server / request handling                                           */
/* ------------------------------------------------------------------ */
typedef struct {
  const char *port;
  const char *endpoint;
  const char *model;
  const char *user_agent; /* empty string => use DEFAULT_UA */
  long max_body_bytes;
  int max_connections;
} config_t;

typedef struct {
  char method[16];
  char path[4096];
  char content_type[256];
  long content_length;
  char ua_override[1024];
  bool has_x_ua;
  char *body;
  size_t body_len;
} http_req_t;

void http_req_free(http_req_t *r);

/* Read the full HTTP request header block from fd into buf. Returns 0
 * on success, -1 on error/timeout. */
int read_headers(int fd, strbuf *buf);

/* Parse a buffered HTTP request. Returns 0 on success. */
int parse_http_request(strbuf *buf, int fd, http_req_t *req, long max_body_bytes);

/* Handle one accepted client connection (reads request, routes,
 * writes response). */
void handle_connection(int fd, const config_t *cfg);

#endif /* HYGATE_H */