/*
 * Linker wrap stubs for FILE*-based printf functions.
 *
 * ESP-IDF SDK components (gpio driver, ringbuf, log_write) reference
 * fprintf(), printf(), vprintf(), and vfprintf() which pull in the full
 * printf implementation (~11 KB on newlib's _vfprintf_r, ~2.8 KB on
 * picolibc's vfprintf). This is a separate implementation from the one
 * used by snprintf/vsnprintf that handles FILE* stream I/O with buffering
 * and locking.
 *
 * ESPHome replaces the ESP-IDF log handler via esp_log_set_vprintf_(),
 * so the SDK's vprintf() path is dead code at runtime. The fprintf()
 * and printf() calls in SDK components are only in debug/assert paths
 * (gpio_dump_io_configuration, ringbuf diagnostics) that are either
 * GC'd or never called. Crash backtraces and panic output are
 * unaffected; they use esp_rom_printf() which is a ROM function
 * and does not go through libc.
 *
 * On picolibc (default for IDF >= 5 on RISC-V, IDF >= 6 everywhere) we
 * route output through a stack-allocated cookie FILE that forwards each
 * byte to the real target stream via fputc(). Picolibc's tinystdio
 * vfprintf walks the FILE::put callback one character at a time, so this
 * costs ~32 bytes of stack for the cookie struct vs. a 512-byte format
 * buffer. The buffered path overflows the loopTask stack on IDF 6.
 *
 * On newlib (IDF <= 5 on Xtensa) we keep the original snprintf-then-fwrite
 * path because that loopTask stack budget has plenty of headroom for the
 * 512-byte buffer; the picolibc-only crash above does not affect it.
 *
 * Saves ~11 KB of flash on newlib, ~2.8 KB on picolibc.
 *
 * To disable these wraps, set enable_full_printf: true in the esp32
 * advanced config section.
 */

#if defined(USE_ESP_IDF) && !defined(USE_FULL_PRINTF)
#include <cstdarg>
#include <cstdio>

#ifndef __PICOLIBC__
#include "esp_system.h"
#endif

namespace esphome::esp32 {}

// NOLINTBEGIN(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp,readability-identifier-naming)
extern "C" {

#ifdef __PICOLIBC__

#include <cstddef>
#include <type_traits>

extern int __real_vfprintf(FILE *stream, const char *fmt, va_list ap);

namespace {

struct CookieFile {
  FILE base;
  FILE *target;
};

// cookie_put() recovers CookieFile* from FILE* via reinterpret_cast, which is
// only well-defined when FILE is the first member at offset 0 and CookieFile
// is standard-layout.
static_assert(offsetof(CookieFile, base) == 0, "FILE must be the first member of CookieFile");
static_assert(std::is_standard_layout<CookieFile>::value, "CookieFile must be standard-layout");

int cookie_put(char c, FILE *stream) {
  auto *cookie = reinterpret_cast<CookieFile *>(stream);
  return fputc(static_cast<unsigned char>(c), cookie->target);
}

const FILE COOKIE_FILE_TEMPLATE = FDEV_SETUP_STREAM(cookie_put, nullptr, nullptr, _FDEV_SETUP_WRITE);

}  // namespace

int __wrap_vfprintf(FILE *stream, const char *fmt, va_list ap) {
  CookieFile cookie;
  cookie.base = COOKIE_FILE_TEMPLATE;
  cookie.target = stream;
  return __real_vfprintf(&cookie.base, fmt, ap);
}

int __wrap_vprintf(const char *fmt, va_list ap) { return __wrap_vfprintf(stdout, fmt, ap); }

#else  // !__PICOLIBC__

static constexpr size_t PRINTF_BUFFER_SIZE = 512;

// These stubs are essentially dead code at runtime — ESPHome replaces the
// ESP-IDF log handler, and the SDK's printf/fprintf calls only exist in
// debug/assert paths that are never reached in normal operation.
// The buffer overflow check is purely defensive and should never trigger.
static int write_printf_buffer(FILE *stream, char *buf, int len) {
  if (len < 0) {
    return len;
  }
  size_t write_len = len;
  if (write_len >= PRINTF_BUFFER_SIZE) {
    fwrite(buf, 1, PRINTF_BUFFER_SIZE - 1, stream);
    esp_system_abort("printf buffer overflow; set enable_full_printf: true in esp32 framework advanced config");
  }
  if (fwrite(buf, 1, write_len, stream) < write_len || ferror(stream)) {
    return -1;
  }
  return len;
}

int __wrap_vprintf(const char *fmt, va_list ap) {
  char buf[PRINTF_BUFFER_SIZE];
  return write_printf_buffer(stdout, buf, vsnprintf(buf, sizeof(buf), fmt, ap));
}

int __wrap_vfprintf(FILE *stream, const char *fmt, va_list ap) {
  char buf[PRINTF_BUFFER_SIZE];
  return write_printf_buffer(stream, buf, vsnprintf(buf, sizeof(buf), fmt, ap));
}

#endif  // __PICOLIBC__

int __wrap_printf(const char *fmt, ...) {
  va_list ap;
  va_start(ap, fmt);
  int len = __wrap_vprintf(fmt, ap);
  va_end(ap);
  return len;
}

int __wrap_fprintf(FILE *stream, const char *fmt, ...) {
  va_list ap;
  va_start(ap, fmt);
  int len = __wrap_vfprintf(stream, fmt, ap);
  va_end(ap);
  return len;
}

}  // extern "C"
// NOLINTEND(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp,readability-identifier-naming)

#endif  // USE_ESP_IDF && !USE_FULL_PRINTF