#include <stdio.h>   // for NULL
#include <stdlib.h>  // for free, realloc, malloc
#include <string.h>  // for memmove, memcpy

#include "row.h"
#include "fn.h"      // for erow, E, editorConfig, FN_TAB_STOP, abuf
#include "hl.h"      // for editorUpdateSyntax


void abAppend(struct abuf *ab, const char *s, int len) {
  char *new = realloc(ab->b, ab->len + len);
  if (new == NULL) return;
  memcpy(&new[ab->len], s, len);
  ab->b = new;
  ab->len += len;
}
void abFree(struct abuf *ab) {
  free(ab->b);
}


char *editorRowsToString(int *buflen) {
  int totlen = 0;
  int j;
  for (j=0; j<E.numrows; j++) {
    totlen += E.row[j].size + 1;
  }
  *buflen = totlen;

  char *buf = malloc(totlen);
  char *p = buf;
  for (j=0; j<E.numrows; j++) {
    memcpy(p, E.row[j].chars, E.row[j].size);
    p += E.row[j].size;
    *p = '\n';
    p++;
  }

  return buf;
}

int editorRowCxToRx(erow *row, int cx) {
  int rx = 0;
  int j;
  for (j=0; j<cx; j++) {
    if (row->chars[j] == '\t') {
      rx += (FN_TAB_STOP - 1) - (rx % FN_TAB_STOP);
    }
    rx++;
  }
  return rx;
}

int editorRowRxToCx(erow *row, int rx) {
  int cur_rx = 0;
  int cx;
  for (cx=0; cx < row->size; cx++) {
    if (row->chars[cx] == '\t')
      cur_rx += (FN_TAB_STOP - 1) - (cur_rx % FN_TAB_STOP);
    cur_rx++;

    if (cur_rx > rx) return cx;
  }
  return cx;
}

void editorUpdateRow(erow *row) {
  int tabs = 0;
  int j;
  for (j=0; j<row->size; j++) {
    if (row->chars[j] == '\t') tabs++;
  }

  free(row->render);
  row->render = malloc(row->size + tabs*(FN_TAB_STOP - 1) + 1);

  int idx = 0;
  for (j=0; j<row->size; j++) {
    if (row->chars[j] == '\t') {
      row->render[idx++] = ' ';
      while (idx % FN_TAB_STOP != 0) row->render[idx++] = ' ';
    } else {
      row->render[idx++] = row->chars[j];
    }
  }
  row->render[idx] = '\0';
  row->rsize = idx;

  editorUpdateSyntax(row);
}

void editorInsertRow(int at, char *s, size_t len) {
  if (at < 0 || at > E.numrows) return;

  E.row = realloc(E.row, sizeof(erow) * (E.numrows +1));
  memmove(&E.row[at + 1], &E.row[at], sizeof(erow) * (E.numrows - at));
  for (int j=at+1; j<= E.numrows; j++) E.row[j].idx++;

  E.row[at].idx = at;

  E.row[at].size = len;
  E.row[at].chars = malloc(len + 1);
  memcpy(E.row[at].chars, s, len);
  E.row[at].chars[len] = '\0';

  E.row[at].rsize = 0;
  E.row[at].render = NULL;
  E.row[at].hl = NULL;
  E.row[at].hl_open_comment = 0;
  editorUpdateRow(&E.row[at]);

  E.numrows++;
  E.dirty++;
}

void editorFreeRow(erow *row) {
  free(row->render);
  free(row->chars);
  free(row->hl);
}

void editorDelRow(int at) {
  if (at < 0 || at >= E.numrows) return;
  editorFreeRow(&E.row[at]);
  memmove(&E.row[at], &E.row[at + 1], sizeof(erow) * (E.numrows - at -1));
  for (int j=at; j<= E.numrows-1; j++) E.row[j].idx--;
  E.numrows--;
  E.dirty++;
}

void editorRowInsertChar(erow *row, int at, int c) {
  if (at < 0 || at > row->size) at = row->size;
  row->chars = realloc(row->chars, row->size + 2);
  memmove(&row->chars[at + 1], &row->chars[at], row->size - at + 1);
  row->size++;
  row->chars[at] = c;
  editorUpdateRow(row);
  E.dirty++;
}

void editorRowAppendString(erow *row, char *s, size_t len) {
  row->chars = realloc(row->chars, row->size + len + 1);
  memcpy(&row->chars[row->size], s, len);
  row->size += len;
  row->chars[row->size] = '\0';
  editorUpdateRow(row);
  E.dirty++;
}

void editorRowDelChar(erow *row, int at) {
  if (at < 0 || at >= row->size) return;
  memmove(&row->chars[at], &row->chars[at + 1], row->size - at);
  row->size--;
  editorUpdateRow(row);
  E.dirty++;
}