#pragma once

#include "arch.h"
#include "fmt.h"
#include "iobuf.h"
#include "queue.h"

// Formats data into a caller-supplied buffer.
//
// Returns:
//   Number of bytes that would be written if buf were large enough, like
//   snprintf().
// Example:
//   char buf[20];
//   mg_snprintf(buf, sizeof(buf), "{%m:%d}", MG_ESC("status"), 1);
// Full examples:
//   tutorials/http/link-checker, tutorials/http/redirect-to-https,
//   tutorials/mqtt/mqtt-dashboard/device
// Related APIs:
//   mg_xprintf(), mg_printf(), mg_mprintf(), MG_ESC
// Notes:
//   These functions are just wrappers around mg_xprintf().
//   Call with buf=NULL and len=0 to measure. NUL-terminates if the result fits
//   (return value < len). Supports mg_xprintf specifiers, including custom
//   %M/%m printers. Use MG_ESC when printing JSON strings.
size_t mg_vsnprintf(char *buf, size_t len, const char *fmt, va_list *ap);
size_t mg_snprintf(char *buf, size_t len, const char *fmt, ...);

// Formats into a heap-allocated NUL-terminated string. Caller must mg_free() it.
char *mg_vmprintf(const char *fmt, va_list *ap);
char *mg_mprintf(const char *fmt, ...);

// Formats into a mg_queue slot. Returns bytes written, or 0 if no space.
size_t mg_queue_printf(struct mg_queue *, const char *fmt, ...);

// Built-in %M/%m printer functions. Each reads its argument(s) from ap.
size_t mg_print_base64(mg_pfn_t, void *arg, va_list *ap);   // expects: const void *buf, size_t len
size_t mg_print_esc(mg_pfn_t, void *arg, va_list *ap);      // expects: int len, const char *str -- use MG_ESC()
size_t mg_print_hex(mg_pfn_t, void *arg, va_list *ap);      // expects: const void *buf, size_t len
size_t mg_print_ip(mg_pfn_t, void *arg, va_list *ap);       // expects: const struct mg_addr *
size_t mg_print_ip_port(mg_pfn_t, void *arg, va_list *ap);  // expects: const struct mg_addr *
size_t mg_print_ip4(mg_pfn_t, void *arg, va_list *ap);      // expects: uint32_t *ipv4
size_t mg_print_ip6(mg_pfn_t, void *arg, va_list *ap);      // expects: uint8_t[16] ipv6
size_t mg_print_mac(mg_pfn_t, void *arg, va_list *ap);      // expects: uint8_t[6] mac
size_t mg_print_ieee64(mg_pfn_t, void *arg, va_list *ap);   // expects: uint64_t
size_t mg_print_l2addr(mg_pfn_t, void *arg, va_list *ap);   // expects: uint8_t l2, uint8_t[n] n-byte l2-dependent address
size_t mg_print_html_esc(mg_pfn_t, void *arg, va_list *ap); // expects: int len, const char *str -- use MG_ESC()


// Output functions for use as the fn argument to mg_xprintf/mg_vxprintf.
void mg_pfn_iobuf(char ch, void *param);           // param: struct mg_iobuf * (resizes as needed)
void mg_pfn_iobuf_noresize(char ch, void *param);  // param: struct mg_iobuf * (fixed buffer, no resize)
void mg_pfn_stdout(char c, void *param);           // param: ignored, writes to stdout

// Expands to the three arguments for %m to JSON-escape a string literal.
// Example: mg_snprintf(buf, len, "%m", MG_ESC("hello")) -> "\"hello\""
#define MG_ESC(str) mg_print_esc, 0, (str)