/* vi: set ts=2:
+-------------------+  Christian Schlittchen <corwin@amber.kn-bremen.de>
|                   |  Enno Rehling <enno@eressea.de>
| Eressea PBEM host |  Katja Zedel <katze@felidae.kn-bremen.de>
| (c) 1998 - 2003   |  Henning Peters <faroul@beyond.kn-bremen.de>
|                   |  Ingo Wilken <Ingo.Wilken@informatik.uni-oldenburg.de>
+-------------------+  Stefan Reich <reich@halbling.de>

This program may not be used, modified or distributed
without prior permission by the authors of Eressea.
*/
#include <platform.h>
#include "log.h"
#include "unicode.h"

#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <stdarg.h>
#include <time.h>

/* TODO: set from external function */
int log_flags = LOG_FLUSH | LOG_CPERROR | LOG_CPWARNING | LOG_CPDEBUG;
int log_stderr = LOG_FLUSH | LOG_CPERROR | LOG_CPWARNING;

#ifdef STDIO_CP
static int stdio_codepage = STDIO_CP;
#else
static int stdio_codepage = 0;
#endif
static FILE *logfile;

#define MAXLENGTH 4096          /* because I am lazy, CP437 output is limited to this many chars */
#define LOG_MAXBACKUPS 5
void log_flush(void)
{
  if (logfile) fflush(logfile);
}

void log_puts(const char *str)
{
  fflush(stdout);
  if (logfile) {
    fputs(str, logfile);
  }
}

static int
cp_convert(const char *format, char *buffer, size_t length, int codepage)
{
  /* when console output on MSDOS, convert to codepage */
  const char *input = format;
  char *pos = buffer;

  while (pos + 1 < buffer + length && *input) {
    size_t length = 0;
    int result = 0;
    if (codepage == 437) {
      result = unicode_utf8_to_cp437(pos, input, &length);
    } else if (codepage == 1252) {
      result = unicode_utf8_to_cp1252(pos, input, &length);
    }
    if (result != 0) {
      *pos = 0;                 /* just in case caller ignores our return value */
      return result;
    }
    ++pos;
    input += length;
  }
  *pos = 0;
  return 0;
}

void log_rotate(const char *filename, int maxindex)
{
  int n;
  if (_access(filename, 4)==0) {
    char buffer[2][MAX_PATH];
    int src = 1;
    assert(strlen(filename)<sizeof(buffer[0])-4);
    for(n=0;n<maxindex;++n) {
      sprintf(buffer[0], "%s.%d", filename, n);
      if (_access(filename, 0)!=0) {
        break;
      }
    }
    if (_access(buffer[0], 0)==0) {
      unlink(buffer[0]);
    }
    while(n--) {
      int dst = 1-src;
      sprintf(buffer[src], "%s.%d", filename, n);
      rename(buffer[src], buffer[dst]);
      src=dst;
    }
    rename(filename, buffer[1-src]);
  }
}

void log_open(const char *filename)
{
  if (logfile) {
    log_close();
  }
  log_rotate(filename, LOG_MAXBACKUPS);
  logfile = fopen(filename, "a");
  if (logfile) {
    /* Get UNIX-style time and display as number and string. */
    time_t ltime;
    time(&ltime);
    fprintf(logfile, "===\n=== Logfile started at %s===\n", ctime(&ltime));
  }
}

void log_close(void)
{
  if (!logfile || logfile == stderr || logfile == stdout)
    return;
  if (logfile) {
    /* Get UNIX-style time and display as number and string. */
    time_t ltime;
    time(&ltime);
    fprintf(logfile, "===\n=== Logfile closed at %s===\n\n", ctime(&ltime));
    fclose(logfile);
  }
  logfile = 0;
}

static int check_dupe(const char *format, const char *type)
{
  static const char *last_type; /* STATIC_XCALL: used across calls */
  static char last_message[32]; /* STATIC_XCALL: used across calls */
  static int dupes = 0;         /* STATIC_XCALL: used across calls */
  if (strncmp(last_message, format, sizeof(last_message)) == 0) {
    ++dupes;
    return 1;
  }
  if (dupes) {
    if (log_flags & LOG_CPERROR) {
      fprintf(stderr, "%s: last message repeated %d times\n", last_type,
        dupes + 1);
    }
    dupes = 0;
  }
  strncpy(last_message, format, sizeof(last_message));
  last_type = type;
  return 0;
}

static void _log_write(FILE * stream, int codepage, const char * prefix, const char *format, va_list args)
{
  if (stream) {
    fprintf(stream, "%s: ", prefix);
    if (codepage) {
      char buffer[MAXLENGTH];
      char converted[MAXLENGTH];

      vsnprintf(buffer, sizeof(buffer), format, args);
      if (cp_convert(buffer, converted, MAXLENGTH, codepage) == 0) {
        fputs(converted, stream);
      } else {
        /* fall back to non-converted output */
        vfprintf(stream, format, args);
      }
    } else {
      vfprintf(stream, format, args);
    }
  }
}

static void _log_writeln(FILE * stream, int codepage, const char * prefix, const char *format, va_list args)
{
    size_t len = strlen(format);
    _log_write(stream, codepage, prefix, format, args);
    if (format[len-1]!='\n') {
        fputc('\n', stream);
    }
}
void log_debug(const char *format, ...)
{
  const char * prefix = "DEBUG";
  const int mask = LOG_CPDEBUG;

  /* write to the logfile, always */
  if (logfile && (log_flags & mask)) {
    va_list args;
    va_start(args, format);
    _log_writeln(logfile, 0, prefix, format, args);
    va_end(args);
  }

  /* write to stderr, if that's not the logfile already */
  if (logfile!=stderr && (log_stderr & mask)) {
    int dupe = check_dupe(format, prefix);
    if (!dupe) {
      va_list args;
      va_start(args, format);
      _log_writeln(stderr, stdio_codepage, prefix, format, args);
      va_end(args);
    }
  }
  if (log_flags & LOG_FLUSH) {
    log_flush();
  }
}

void log_warning(const char *format, ...)
{
  const char * prefix = "WARNING";
  const int mask = LOG_CPWARNING;

  /* write to the logfile, always */
  if (logfile && (log_flags & mask)) {
    va_list args;
    va_start(args, format);
    _log_writeln(logfile, 0, prefix, format, args);
    va_end(args);
  }

  /* write to stderr, if that's not the logfile already */
  if (logfile!=stderr && (log_stderr & mask)) {
    int dupe = check_dupe(format, prefix);
    if (!dupe) {
      va_list args;
      va_start(args, format);
      _log_writeln(stderr, stdio_codepage, prefix, format, args);
      va_end(args);
    }
  }
  if (log_flags & LOG_FLUSH) {
    log_flush();
  }
}

void log_error(const char *format, ...)
{
  const char * prefix = "ERROR";
  const int mask = LOG_CPERROR;

  /* write to the logfile, always */
  if (logfile && (log_flags & mask)) {
    va_list args;
    va_start(args, format);
    _log_writeln(logfile, 0, prefix, format, args);
    va_end(args);
  }

  /* write to stderr, if that's not the logfile already */
  if (logfile!=stderr && (log_stderr & mask)) {
    int dupe = check_dupe(format, prefix);
    if (!dupe) {
      va_list args;
      va_start(args, format);
      _log_writeln(stderr, stdio_codepage, prefix, format, args);
      va_end(args);
    }
  }
  if (log_flags & LOG_FLUSH) {
    log_flush();
  }
}

void log_info(const char *format, ...)
{
  const char * prefix = "INFO";
  const int mask = LOG_CPINFO;

  /* write to the logfile, always */
  if (logfile && (log_flags & mask)) {
    va_list args;
    va_start(args, format);
    _log_writeln(logfile, 0, prefix, format, args);
    va_end(args);
  }

  /* write to stderr, if that's not the logfile already */
  if (logfile!=stderr && (log_stderr & mask)) {
    int dupe = check_dupe(format, prefix);
    if (!dupe) {
      va_list args;
      va_start(args, format);
      _log_writeln(stderr, stdio_codepage, prefix, format, args);
      va_end(args);
    }
  }
  if (log_flags & LOG_FLUSH) {
    log_flush();
  }
}

void log_printf(FILE * io, const char *format, ...)
{
  const char * prefix = "INFO";
  const int mask = LOG_CPINFO;

  /* write to the logfile, always */
  if (logfile && (log_flags & mask)) {
    int codepage = (logfile==stderr || logfile==stdout) ? stdio_codepage : 0;
    va_list args;
    va_start(args, format);
    _log_write(logfile, codepage, prefix, format, args);
    va_end(args);
  }

  /* write to io, if that's not the logfile already */
  if (logfile!=io && (log_stderr & mask)) {
    int dupe = check_dupe(format, prefix);
    if (!dupe) {
      va_list args;
      va_start(args, format);
      _log_write(io, stdio_codepage, prefix, format, args);
      va_end(args);
    }
  }
  if (log_flags & LOG_FLUSH) {
    log_flush();
  }
}