/*	$Id$ */
/*
 * 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 <inttypes.h>
#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 "extern.h"

/*
 * Start with five pages.
 * As you add more pages, you'll start by giving them an identifier key
 * in this enum.
 */
enum	page {
	PAGE_INDEX,
	PAGE_BOOKS,
	PAGE_AUTHORS,
	PAGE_SERIES,
	PAGE__MAX
};

enum key {
  KEY_ID,
  KEY_PAGE,
  KEY_PERPAGE,
  KEY__MAX
};

static const char *const pages[PAGE__MAX] = {
	"index", /* PAGE_INDEX */
	"books", /* PAGE_BOOKS */
	"authors", /* PAGE_AUTHORS */
	"series", /* PAGE_SERIES */
};

static const struct kvalid keys[KEY__MAX] = {
  { kvalid_int, "id" }, /* KEY_ID */
  { kvalid_int, "page" }, /* KEY_PAGE */
  { kvalid_int, "perpage" }, /* KEY_PERPAGE */
};

/*
 * Fill out all HTTP secure headers.
 * Use the existing document's MIME type.
 */
static void
http_alloc(struct kreq *r, enum khttp code)
{

	khttp_head(r, kresps[KRESP_STATUS], 
		"%s", khttps[code]);
	khttp_head(r, kresps[KRESP_CONTENT_TYPE], 
		"%s", kmimetypes[r->mime]);
	khttp_head(r, "X-Content-Type-Options", "nosniff");
	khttp_head(r, "X-Frame-Options", "DENY");
	khttp_head(r, "X-XSS-Protection", "1; mode=block");
}

/*
 * Fill out all headers with http_alloc() then start the HTTP document
 * body (no more headers after this point!)
 */
static void
http_open(struct kreq *r, enum khttp code)
{

	http_alloc(r, code);
	khttp_body(r);
}

static void
puterror(struct kjsonreq *req, char *message)
{
  kjson_obj_open(req);
  kjson_putstringp(req, "msg", message);
  kjson_obj_close(req);
}

/*
 * Append author object to json (NOT CLOSED).
 */
static void
putauthor(struct kjsonreq *req, Author *a)
{
  kjson_obj_open(req);
  kjson_putintp(req, "id", a->id);
  kjson_putstringp(req, "name", a->name);
}

/*
 * Append book object to json (NOT CLOSED).
 */
static void
putbook(struct kjsonreq *req, Book *b)
{
  kjson_obj_open(req);
  kjson_putintp(req, "id", b->id);
  kjson_putstringp(req, "title", b->title);
  if (b->s.id >= 0) {
    kjson_objp_open(req, "series");
    kjson_putintp(req, "id", b->s.id);
    kjson_putstringp(req, "name", b->s.name);
    kjson_putdoublep(req, "idx", b->s_idx);
    kjson_obj_close(req);
  }
}

static void
putbookdata(struct kjsonreq *req, BookFull *b)
{
  if (b->dsize > 0) {
    kjson_arrayp_open(req, "data");
    for (size_t i=0;i<b->dsize;i++) {
      kjson_obj_open(req);
      kjson_putstringp(req, "name", b->data[i]->name);
      kjson_putstringp(req, "format", b->data[i]->format);
      kjson_putintp(req, "size", b->data[i]->size);
      kjson_obj_close(req);
    }
    kjson_array_close(req);
  }
}

static void
putauthors(struct kjsonreq *req, BookAdv *b)
{
  if (b->asize > 0) {
    kjson_arrayp_open(req, "authors");
    for (size_t j=0; j<b->asize; j++) {
      putauthor(req, b->a[j]);
      kjson_obj_close(req);
    }
    kjson_array_close(req);
  }
}

static void
putbookfull(struct kjsonreq *req, BookFull *b)
{
  char tsstr[30];

  putbook(req, &b->ba.b);
  kutil_epoch2str(b->timestamp, tsstr, sizeof(tsstr));
  kjson_putstringp(req, "timestamp", tsstr);
  kjson_putintp(req, "pubdate", b->pubdate);
  kjson_putstringp(req, "isbn", b->isbn);
  kjson_putstringp(req, "lccn", b->lccn);
  kjson_putstringp(req, "path", b->path);
  kjson_putstringp(req, "uuid", b->uuid);
  kjson_putboolp(req, "has_cover", b->has_cover);
  kjson_putstringp(req, "lang", b->lang);
  if (NULL != b->publisher)
    kjson_putstringp(req, "publisher", b->publisher);
}

static void
sendbooks(struct kreq *r)
{
  struct kjsonreq    req;
  const char *errid;
  int64_t id = -1;
  BookFull *b = NULL;
  int res, i = 0, page = 1, per = 20;

  if (NULL != r->fieldmap[KEY_PAGE])
    page = r->fieldmap[KEY_PAGE]->parsed.i; 
  if (NULL != r->fieldmap[KEY_PERPAGE])
    per = r->fieldmap[KEY_PERPAGE]->parsed.i; 
  if (NULL != r->fieldmap[KEY_ID])
    id = r->fieldmap[KEY_ID]->parsed.i;
  if (r->path[0] != '\0')
    id = strtonum(r->path, INT64_MIN, INT64_MAX, &errid);
  if (id >= 0) {
    b = db_book_load(r, id);
  }
  http_open(r, (id > 0 && NULL == b) ? KHTTP_404 : KHTTP_200);
  kjson_open(&req, r);
  if (id >= 0 && NULL == b) {
    puterror(&req, "Unknown book");
  } else if (NULL != b) {
    putbookfull(&req, b);
    putauthors(&req, &b->ba);
    putbookdata(&req, b);
    kjson_obj_close(&req);
    db_book_full_free(b);
  } else {
    kjson_array_open(&req);
    BookAdv **books = kcalloc(per, sizeof(BookAdv));
    res = db_books_load(r, books, per, per * (page-1));
    while (i < res) {
      Book b = books[i]->b;
      putbook(&req, &b);
      putauthors(&req, books[i]);
      kjson_obj_close(&req);
      db_book_adv_free(books[i]);
      i++;
    }
    free(books);
    kjson_array_close(&req);
  }
  kjson_close(&req);
}

static void
sendauthors(struct kreq *r)
{
  struct kjsonreq    req;

  http_open(r, KHTTP_200);
  kjson_open(&req, r);
  kjson_obj_open(&req);
  kjson_putstringp(&req, "data", "authors");
  kjson_obj_close(&req);
  kjson_close(&req);
}

static void
sendseries(struct kreq *r)
{
  struct kjsonreq    req;

  http_open(r, KHTTP_200);
  kjson_open(&req, r);
  kjson_obj_open(&req);
  kjson_putstringp(&req, "data", "series");
  kjson_obj_close(&req);
  kjson_close(&req);
}

static void
sendindex(struct kreq *r)
{
  struct kjsonreq    req;

  http_open(r, KHTTP_200);
  kjson_open(&req, r);
  kjson_obj_open(&req);
  kjson_putintp(&req, "count", db_books_count(r));
  kjson_obj_close(&req);
  kjson_close(&req);
}

int
main(void)
{
	struct kreq	 r;
	enum kcgi_err	 er;

	/* Actually parse HTTP document. */

	er = khttp_parsex(&r, ksuffixmap, 
          kmimetypes, KMIME__MAX, keys, KEY__MAX,
          pages, PAGE__MAX, KMIME_APP_JSON, 
          PAGE_INDEX, NULL, NULL, 0, NULL);

	if (KCGI_OK != er) {
		fprintf(stderr, "HTTP parse error: %d\n", er);
		return(EXIT_FAILURE);
	}

#ifdef	__OpenBSD__
	if (-1 == pledge("stdio rpath cpath wpath flock fattr", NULL)) {
    fputs("pledge", stderr);
		khttp_free(&r);
		return(EXIT_FAILURE);
	}
#endif

	/*
	 * Front line of defence: make sure we're a proper method, make
	 * sure we're a page, make sure we're a JSON file.
	 */

	if (KMETHOD_GET != r.method && 
	    KMETHOD_POST != r.method) {
		http_open(&r, KHTTP_405);
		khttp_free(&r);
		return(EXIT_SUCCESS);
	} else if (PAGE__MAX == r.page || 
	           KMIME_APP_JSON != r.mime) {
		http_open(&r, KHTTP_404);
		khttp_puts(&r, "Page not found.");
		khttp_free(&r);
		return(EXIT_SUCCESS);
	}

	if ( ! db_open(&r, DATADIR "/" DATABASE)) {
		http_open(&r, KHTTP_500);
		json_emptydoc(&r);
		khttp_free(&r);
		return(EXIT_SUCCESS);
	}

	switch (r.page) {
	case (PAGE_INDEX):
		sendindex(&r);
		break;
	case (PAGE_BOOKS):
		sendbooks(&r);
		break;
	case (PAGE_AUTHORS):
		sendauthors(&r);
		break;
	case (PAGE_SERIES):
		sendseries(&r);
		break;
	default:
		abort();
	}

	db_close(&r);
	khttp_free(&r);
	return(EXIT_SUCCESS);
}