/*---
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---*/

/**
   @file Abstract log implementation.  Provides access to methods that
   directly read and write log entries, force the log to disk, etc.

   @todo Switch logger2 to use function pointers
*/

#include <config.h>
#include <stasis/common.h>

#include <stdio.h>
#include <assert.h>

#include <stasis/logger/logger2.h>

#include "logWriter.h"
#include "inMemoryLog.h"
#include "page.h"  

#ifdef USE_LOGGER
int loggerType = USE_LOGGER;
#else
int loggerType = LOG_TO_FILE;
#endif

extern int numActiveXactions;
static int pendingCommits;
static int syncLogCount;

long LoggerSizeOfInternalLogEntry(const LogEntry * e) {
  if(loggerType == LOG_TO_FILE) { 
    return sizeofInternalLogEntry_LogWriter(e);
  } else if (loggerType == LOG_TO_MEMORY) {
    return sizeofInternalLogEntry_InMemoryLog(e);   
  } else {
    // we dont have an appropriate implementation, or weren't initialized...
    abort();
  }
}

void LogWrite(LogEntry * e) { 
  if(loggerType == LOG_TO_FILE) { 
    writeLogEntry(e);
  } else if (loggerType == LOG_TO_MEMORY) {
    writeLogEntry_InMemoryLog(e);
  } else { 
    abort();
  }
  return;
}

int LogInit(int logType) { 

  loggerType = logType;

  pendingCommits = 0;
  syncLogCount = 0;
  if(LOG_TO_FILE == logType) { 
    openLogWriter();
  } else if(LOG_TO_MEMORY == logType) { 
    open_InMemoryLog();
  } else { 
    return -1;
  }
  return 0;
}

int LogDeinit() { 
  if(LOG_TO_FILE == loggerType) { 
    closeLogWriter();
  } else if(LOG_TO_MEMORY == loggerType) { 
    close_InMemoryLog();
  } else { 
    abort();
  }
  return 0;
}

void LogForce(lsn_t lsn) { 
  lsn_t flushedLSN = LogFlushedLSN();
  if(flushedLSN < lsn) {
    if(LOG_TO_FILE == loggerType) { 
      syncLog_LogWriter();
    } else if (LOG_TO_MEMORY == loggerType) { 
      syncLog_InMemoryLog();
    } else { 
      abort();
    }
  }
  assert(LogFlushedLSN() >= lsn);
}
void LogTruncate(lsn_t lsn) { 
  if(LOG_TO_FILE == loggerType) { 
    truncateLog_LogWriter(lsn);
  } else if(LOG_TO_MEMORY == loggerType) { 
    truncateLog_InMemoryLog(lsn);
  } else { 
    abort();
  }
}

lsn_t LogFlushedLSN() { 
  lsn_t ret;
  if(LOG_TO_FILE == loggerType) { 
    ret = flushedLSN_LogWriter();
  } else if(LOG_TO_MEMORY == loggerType) { 
    ret = flushedLSN_InMemoryLog();
  } else {
    abort();
  }
  return ret;
}

lsn_t LogTruncationPoint() { 
  lsn_t ret;
  if(LOG_TO_FILE == loggerType) { 
    ret =  firstLogEntry();
  } else if(LOG_TO_MEMORY == loggerType) { 
    ret = firstLogEntry_InMemoryLog();
  } else { 
    abort();
  }
  return ret;
}
const LogEntry * LogReadLSN(lsn_t lsn) { 
  LogEntry * ret;
  if(LOG_TO_FILE == loggerType) { 
    ret = readLSNEntry_LogWriter(lsn);
  } else if(LOG_TO_MEMORY == loggerType) { 
    ret = readLSNEntry_InMemoryLog(lsn);
  } else {
    abort();
  }
  return ret;
}

lsn_t LogNextEntry(const LogEntry * e) { 
  lsn_t ret;
  if(LOG_TO_FILE == loggerType) { 
    ret = nextEntry_LogWriter(e);
  } else if(LOG_TO_MEMORY == loggerType) { 
    ret = nextEntry_InMemoryLog(e);
  } else {
    abort();
  }
  return ret;
}

void FreeLogEntry(const LogEntry * e) { 
  if(LOG_TO_FILE == loggerType) { 
    free((void*)e);
  } else if(LOG_TO_MEMORY == loggerType) {
    free((void*)e);
  } else { 
    abort();
  }

}

TransactionLog LogTransBegin(int xid) {
  TransactionLog tl;
  tl.xid = xid;
  
  DEBUG("Log Begin %d\n", xid);
  tl.prevLSN = -1;
  tl.recLSN = -1;
  return tl;
}

static lsn_t LogTransCommon(TransactionLog * l, int type) {
  LogEntry * e = allocCommonLogEntry(l->prevLSN, l->xid, type);
  lsn_t ret;

  LogWrite(e);

  if(l->prevLSN == -1) { l->recLSN = e->LSN; }
  l->prevLSN = e->LSN;
  DEBUG("Log Common %d, LSN: %ld type: %ld (prevLSN %ld)\n", e->xid, 
	 (long int)e->LSN, (long int)e->type, (long int)e->prevLSN);

  ret = e->LSN;

  FreeLogEntry(e);

  return ret;

}

/**
   @todo This should be usable by all calls that sync the log; not just commit.
*/
static lsn_t groupCommit(TransactionLog * l) {
  static pthread_mutex_t check_commit = PTHREAD_MUTEX_INITIALIZER;
  static pthread_cond_t tooFewXacts = PTHREAD_COND_INITIALIZER;

  lsn_t ret = LogTransCommon(l, XCOMMIT);

  struct timeval now;
  struct timespec timeout;
  
  pthread_mutex_lock(&check_commit);
  if(LogFlushedLSN() >= ret) {
    pthread_mutex_unlock(&check_commit);
    return ret;
  }
  gettimeofday(&now, NULL);
  timeout.tv_sec = now.tv_sec;
  timeout.tv_nsec = now.tv_usec * 1000;
  //                   0123456789  <- number of zeros on the next three lines...
  timeout.tv_nsec +=   100000000; // wait ten msec.
  if(timeout.tv_nsec > 1000000000) {
    timeout.tv_nsec -= 1000000000;
    timeout.tv_sec++;
  }

  pendingCommits++;
  if((numActiveXactions > 1 && pendingCommits < numActiveXactions) ||
     (numActiveXactions > 20 && pendingCommits < (int)((double)numActiveXactions * 0.95))) {
    int retcode;
    while(ETIMEDOUT != (retcode = pthread_cond_timedwait(&tooFewXacts, &check_commit, &timeout))) { 
      if(retcode != 0) { 
	printf("Warning: %s:%d: pthread_cond_timedwait was interrupted by a signal in groupCommit().  Acting as though it timed out.\n", __FILE__, __LINE__);
	break;
      }
      if(LogFlushedLSN() >= ret) {
	pendingCommits--;
	pthread_mutex_unlock(&check_commit);
	return ret;
      }
    }
  } 
  if(LogFlushedLSN() < ret) {
    syncLog_LogWriter();
    syncLogCount++;
    pthread_cond_broadcast(&tooFewXacts);
  }
  assert(LogFlushedLSN() >= ret);
  pendingCommits--;
  pthread_mutex_unlock(&check_commit);
  return ret;
}

lsn_t LogTransCommit(TransactionLog * l) { 
  return groupCommit(l);
}

lsn_t LogTransAbort(TransactionLog * l) {
  return LogTransCommon(l, XABORT);
}


/** 
    @todo Does the handling of operation types / argument sizes belong
    here?  Shouldn't it be in logEntry.c, or perhaps with other code
    that reasons about the various operation types?
*/
static LogEntry * LogAction(TransactionLog * l, Page * p, recordid rid, int operation,
		     const byte * args, int deferred) {
  void * preImage = NULL;
  long argSize  = 0;
  LogEntry * e;


  argSize = operationsTable[operation].sizeofData;

  if(argSize == SIZEOF_RECORD) argSize = stasis_record_type_to_size(rid.size);
  if(argSize == SIZEIS_PAGEID) argSize = rid.page;

  int undoType = operationsTable[operation].undo;
  
  if(undoType == NO_INVERSE) {
    DEBUG("Creating %ld byte physical pre-image.\n", stasis_record_type_to_size(rid.size));

    preImage = malloc(stasis_record_type_to_size(rid.size));
    stasis_record_read(l->xid, p, rid, preImage);
  } else if (undoType == NO_INVERSE_WHOLE_PAGE) {
    DEBUG("Logging entire page\n");

    preImage = malloc(PAGE_SIZE);
    memcpy(preImage, p->memAddr, PAGE_SIZE);
  } else { 
    DEBUG("No pre-image");
  }
  
  if(!deferred) { 
    e = allocUpdateLogEntry(l->prevLSN, l->xid, operation, rid, args, argSize, 
			    preImage);
  } else { 
    e = allocDeferredLogEntry(l->prevLSN, l->xid, operation, rid, args, argSize,
			      preImage);
  }
  
  LogWrite(e);
  DEBUG("Log Update %d, LSN: %ld type: %ld (prevLSN %ld) (argSize %ld)\n", e->xid, 
	 (long int)e->LSN, (long int)e->type, (long int)e->prevLSN, (long int) argSize);

  if(preImage) {
    free(preImage);
  }
  if(l->prevLSN == -1) { l->recLSN = e->LSN; }
  l->prevLSN = e->LSN;
  return e;
}

LogEntry * LogUpdate(TransactionLog * l, Page * p, recordid rid, int operation,
		     const byte * args) {
  return LogAction(l, p, rid, operation, args, 0); // 0 -> not deferred
}
LogEntry * LogDeferred(TransactionLog * l, Page * p, recordid rid, int operation,
		     const byte * args) {
  return LogAction(l, p, rid, operation, args, 1); // 1 -> deferred
}

lsn_t LogCLR(const LogEntry * old_e) { 
  LogEntry * e = allocCLRLogEntry(old_e);
  LogWrite(e);

  DEBUG("Log CLR %d, LSN: %ld (undoing: %ld, next to undo: %ld)\n", xid, 
  	 e->LSN, LSN, prevLSN);

  lsn_t ret = e->LSN;
  FreeLogEntry(e);
  return ret;
}

lsn_t LogDummyCLR(int xid, lsn_t prevLSN) { 
  LogEntry * e = allocUpdateLogEntry(prevLSN, xid, OPERATION_NOOP, 
				     NULLRID, NULL, 0, 0);
  lsn_t ret = LogCLR(e);
  FreeLogEntry(e);
  return ret;
}