/*
 * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
 *
 * This program is free software: you can use, redistribute, and/or modify
 * it under the terms of the GNU Affero General Public License, version 3
 * or later ("AGPL"), as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include "index_fst_automation.h"


StartWithStateValue *startWithStateValueCreate(StartWithStateKind kind, ValueType ty, void *val) {
  StartWithStateValue *nsv = calloc(1, sizeof(StartWithStateValue));
  if (nsv == NULL) { return NULL; }

  nsv->kind = kind;
  nsv->type = ty;
  if (ty == FST_INT) {
    nsv->val = *(int *)val;
  } else if (ty == FST_CHAR) {
    size_t len = strlen((char *)val);  
    nsv->ptr = (char *)calloc(1, len + 1);  
    memcpy(nsv->ptr, val, len);
  } else if (ty == FST_ARRAY) {
    //TODO, 
    //nsv->arr = taosArrayFromList() 
  }
  return nsv;
}
void startWithStateValueDestroy(void *val) {
  StartWithStateValue *sv = (StartWithStateValue *)val;
  if (sv == NULL) { return; }

  if (sv->type == FST_INT) {
    //  
  } else if (sv->type == FST_CHAR) {
    free(sv->ptr);
  } else if (sv->type == FST_ARRAY) {
    taosArrayDestroy(sv->arr);
  }
  free(sv); 
}
StartWithStateValue *startWithStateValueDump(StartWithStateValue *sv) {
  StartWithStateValue *nsv = calloc(1, sizeof(StartWithStateValue));
  if (nsv == NULL) { return NULL; }

  nsv->kind = sv->kind;
  nsv->type= sv->type;
  if (nsv->type == FST_INT) {
    nsv->val = sv->val;
  } else if (nsv->type == FST_CHAR) {
    size_t len = strlen(sv->ptr);
    nsv->ptr = (char *)calloc(1, len + 1);
    memcpy(nsv->ptr, sv->ptr, len);
  } else if (nsv->type == FST_ARRAY) {
  }
  return nsv;
}


// prefix query, impl later

static void* prefixStart(AutomationCtx *ctx) {  
  StartWithStateValue *data = (StartWithStateValue *)(ctx->stdata);
  return startWithStateValueDump(data);     
};
static bool prefixIsMatch(AutomationCtx *ctx, void *sv) {
  StartWithStateValue* ssv = (StartWithStateValue *)sv;  
  return ssv->val == strlen(ctx->data); 
} 
static bool prefixCanMatch(AutomationCtx *ctx, void *sv) {
  StartWithStateValue* ssv = (StartWithStateValue *)sv;  
  return ssv->val >= 0; 
}
static bool prefixWillAlwaysMatch(AutomationCtx *ctx, void *state) {
  return true;
}
static void* prefixAccept(AutomationCtx *ctx, void *state, uint8_t byte) {
  StartWithStateValue* ssv = (StartWithStateValue *)state;  
  if (ssv == NULL || ctx == NULL) {return NULL;}

  char *data = ctx->data;
  if (ssv->kind == Done) {
    return startWithStateValueCreate(Done, FST_INT, &ssv->val);
  }
  if ((strlen(data) > ssv->val) && data[ssv->val] == byte) {
    int val = ssv->val + 1;
    StartWithStateValue *nsv = startWithStateValueCreate(Running, FST_INT, &val);
    if (prefixIsMatch(ctx, nsv)) {
      nsv->kind = Done;
    } else {
      nsv->kind = Running;
    } 
    return nsv;
  } 
  return NULL;
}
static void* prefixAcceptEof(AutomationCtx *ctx, void *state) {
  return NULL;
}

// pattern query, impl later

static void* patternStart(AutomationCtx *ctx) {
  return NULL;
}
static bool patternIsMatch(AutomationCtx *ctx, void *data) {
  return true;
} 
static bool patternCanMatch(AutomationCtx *ctx, void *data) {
  return true;
} 
static bool patternWillAlwaysMatch(AutomationCtx *ctx, void *state) {
  return true;
}

static void* patternAccept(AutomationCtx *ctx, void *state, uint8_t byte) {
  return NULL;
}

static void* patternAcceptEof(AutomationCtx *ctx, void *state) {
  return NULL;
}

AutomationFunc automFuncs[]  = {{
    prefixStart,        
    prefixIsMatch, 
    prefixCanMatch,
    prefixWillAlwaysMatch,
    prefixAccept,
    prefixAcceptEof
  },  
  {
    patternStart,
    patternIsMatch,
    patternCanMatch,
    patternWillAlwaysMatch,
    patternAccept,
    patternAcceptEof
  }
  // add more search type
};

AutomationCtx* automCtxCreate(void *data,AutomationType atype) {
  AutomationCtx *ctx = calloc(1, sizeof(AutomationCtx));
  if (ctx == NULL) { return NULL; }

  StartWithStateValue *sv = NULL;
  if (atype == AUTOMATION_PREFIX) {
    int val = 0;
    sv = startWithStateValueCreate(Running, FST_INT, &val);
    ctx->stdata = (void *)sv;
  } else if (atype == AUTMMATION_MATCH) {
      
  } else {
    // add more search type
  }

  char*  src = (char *)data; 
  size_t len = strlen(src);
  char*  dst = (char *)malloc(len * sizeof(char) + 1); 
  memcpy(dst, src, len);
  dst[len] = 0;
  
  ctx->data   = dst; 
  ctx->type   = atype;
  ctx->stdata = (void *)sv; 
  return ctx; 
} 
void automCtxDestroy(AutomationCtx *ctx) {
  startWithStateValueDestroy(ctx->stdata);
  free(ctx->data);
  free(ctx);
}