/*	$Id$ */
/*
 * Copyright (c) 2016 Kristaps Dzonsons <kristaps@bsd.lv>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include <kcgi.h>
#include <kcgijson.h>
#include "ksql.h"

#include "extern.h"

enum    stmt {
  STMT_BOOK,
  STMT_BOOKS,
  STMT_BOOKS_AUTHORS,
  STMT__MAX
};

static const char *const stmts[STMT__MAX] = {
  /* STMT_BOOK */
  "SELECT books.id AS id,title,series_index,name as series_name,series.id AS series_id FROM books LEFT OUTER JOIN books_series_link ON books.id = books_series_link.book LEFT OUTER JOIN series ON series.id = books_series_link.series WHERE books.id = ?",
  /* STMT_BOOKS */
  "SELECT books.id AS id,title,series_index,name as series_name,series.id AS series_id FROM books LEFT OUTER JOIN books_series_link ON books.id = books_series_link.book LEFT OUTER JOIN series ON series.id = books_series_link.series ORDER BY id LIMIT ? OFFSET ?",
  /* STMT_BOOKS_AUTHORS */
  "SELECT authors.id, authors.name, books_authors_link.book as book FROM authors, books_authors_link WHERE books_authors_link.author = authors.id AND books_authors_link.book IN ( SELECT id FROM books ORDER BY id LIMIT ? OFFSET ?)",
};

/*
 * Linked list authors of book.
 */
struct bookauth {
  Author *a;
  BookAdv *b;
  struct bookauth *p;
};

static void
db_series_unfill(Series *p)
{
  if (NULL == p)
    return;
  free(p->name);
}

void
db_series_free(Series *p)
{
  db_series_unfill(p);
  free(p);
}

static void
db_book_unfill(Book *p)
{
  if (NULL == p)
    return;
  free(p->title);
  db_series_unfill(&p->s);
}

static void
db_author_unfill(Author *p) {
  if (NULL == p)
    return;
  free(p->name);
}

void
db_book_free(Book *p)
{
  db_book_unfill(p);
  free(p);
}

void
db_book_adv_free(BookAdv *p)
{
  db_book_unfill(&p->b);
  for (size_t i = 0; i < p->asize; i++) {
    db_author_unfill(p->a[i]);
  }
  free(p);
}

static void
db_book_fill(Book *book, struct ksqlstmt *stmt)
{
  book->id = ksql_stmt_int(stmt, 0);
  book->title = kstrdup(ksql_stmt_str(stmt, 1));
  if ( ksql_stmt_isnull(stmt, 4) ) {
    book->s.id = -1;
  } else {
    book->s_idx = ksql_stmt_double(stmt, 2);
    book->s.name = kstrdup(ksql_stmt_str(stmt, 3));
    book->s.id = ksql_stmt_int(stmt, 4);
  }
}

int
db_books_load(struct kreq *r, BookAdv **books, int limit, int offset)
{
  if (limit < 0 || offset < 0) {
    return 0;
  }
  struct ksqlstmt *stmt;
  struct bookauth *p = NULL;
  struct bookauth *item = NULL;
  int i, count = 0;
  int64_t bid;

  ksql_stmt_alloc(r->arg, &stmt, 
            stmts[STMT_BOOKS], 
            STMT_BOOKS);
  ksql_bind_int(stmt, 0, limit);
  ksql_bind_int(stmt, 1, offset);
  while (KSQL_ROW == ksql_stmt_step(stmt)) {
    books[count] = kcalloc(1, sizeof(BookAdv));
    db_book_fill(&books[count]->b,stmt);
    books[count]->asize = 0;
    count++;
  }
  ksql_stmt_free(stmt);

  ksql_stmt_alloc(r->arg, &stmt, 
            stmts[STMT_BOOKS_AUTHORS], 
            STMT_BOOKS_AUTHORS);
  ksql_bind_int(stmt, 0, limit);
  ksql_bind_int(stmt, 1, offset);
  while (KSQL_ROW == ksql_stmt_step(stmt)) {
    // add author to list, link related book and increment asize
    item = kcalloc(1, sizeof(struct bookauth));
    item->a = kcalloc(1, sizeof(Author));
    item->a->id = ksql_stmt_int(stmt, 0);
    item->a->name = kstrdup(ksql_stmt_str(stmt, 1));
    bid = ksql_stmt_int(stmt, 2);
    for (i = 0; i < count && NULL == item->b; i++) {
      if (books[i]->b.id == bid) {
        item->b = books[i];
        item->b->asize++;
      }
    }
    item->p = p;
    p = item;
  }

  // assign authors to books
  while (NULL != p) {
    if (NULL != p->b && NULL == p->b->a && p->b->asize > 0) {
      p->b->a = kcalloc(p->b->asize, sizeof(Author));
      p->b->asize = 0; // use as counter for insert
    }
    p->b->a[p->b->asize] = p->a;// add author
    p->b->asize++;
    item = p;
    p = p->p;
    free(item);
  }
  ksql_stmt_free(stmt);

  return count;
}

Book *
db_book_load(struct kreq *r, int64_t id)
{
  struct ksqlstmt *stmt;
  Book  *book;

  ksql_stmt_alloc(r->arg, &stmt, 
            stmts[STMT_BOOK], 
            STMT_BOOK);
  ksql_bind_int(stmt, 0, id);
  if (KSQL_ROW != ksql_stmt_step(stmt)) {
    ksql_stmt_free(stmt);
    return(NULL);
  }
  book = kcalloc(1, sizeof(Book));
  db_book_fill(book, stmt);
  ksql_stmt_free(stmt);
  return book;
}

/*
 * Open the database and stash the resulting handle in the d
 */
int
db_open(struct kreq *r, const char *file)
{
	struct ksqlcfg	 cfg;
	struct ksql	*sql;

	/* Configure normal database except with foreign keys. */

	memset(&cfg, 0, sizeof(struct ksqlcfg));
	cfg.flags = KSQL_EXIT_ON_ERR |
		    KSQL_FOREIGN_KEYS |
		    KSQL_SAFE_EXIT;
	cfg.err = ksqlitemsg;
	cfg.dberr = ksqlitedbmsg;

	/* Allocate database. */

	if (NULL == (sql = ksql_alloc(&cfg)))
		return(0);

	ksql_open(sql, file);
	r->arg = sql;
	return(1);
}

/*
 * Close the database stashed in the kreq's argument.
 */
void
db_close(struct kreq *r)
{

	ksql_free(r->arg);
	r->arg = NULL;
}