#include "database.h"

#include <stdio.h>

sqlite3 *
database_connect (const char *path)
{
  sqlite3 *db;

  gchar *file = g_build_filename (path, "cards.db", NULL);
  int rc = sqlite3_open (file, &db);

  if (rc)
    {
      fprintf (stderr, "Can't open database: %s\n", sqlite3_errmsg (db));
      return nullptr;
    }
  fprintf (stdout, "Opened database successfully\n");
  g_free (file);

  database_create_tables (db);

  return db;
}

void
database_close (sqlite3 *db)
{
  sqlite3_close (db);
}

void
database_create_tables (sqlite3 *db)
{
  sqlite3_stmt *stmt;

  const char *sql = "CREATE TABLE IF NOT EXISTS `cards` ("
                    "`id` INTEGER NOT NULL,"
                    "`category` INTEGER NOT NULL,"
                    "`title` TEXT NOT NULL,"
                    "`answer` TEXT NOT NULL,"
                    "`next_time` INTEGER NOT NULL DEFAULT (unixepoch()),"
                    "PRIMARY KEY(`id` AUTOINCREMENT)"
                    ")";

  int rc = sqlite3_prepare_v2 (db, sql, -1, &stmt, nullptr);
  if (rc != SQLITE_OK)
    fprintf (stderr, "Failed to execute statement: %s\n", sqlite3_errmsg (db));

  sqlite3_step (stmt);
  sqlite3_finalize (stmt);

  sql = "CREATE TABLE IF NOT EXISTS `categories` ("
        "`id`	INTEGER NOT NULL,"
        "`name`	TEXT NOT NULL,"
        "PRIMARY KEY(`id` AUTOINCREMENT)"
        ")";

  rc = sqlite3_prepare_v2 (db, sql, -1, &stmt, nullptr);
  if (rc != SQLITE_OK)
    fprintf (stderr, "Failed to execute statement: %s\n", sqlite3_errmsg (db));

  sqlite3_step (stmt);
  sqlite3_finalize (stmt);
}

void
database_save_category (sqlite3 *db, const char *c)
{
  sqlite3_stmt *stmt;

  fprintf (stdout, "%s\n", c);
  int rc = sqlite3_prepare_v2 (db, "INSERT INTO categories (name) VALUES(?)",
                               -1, &stmt, nullptr);
  if (rc == SQLITE_OK)
    sqlite3_bind_text (stmt, 1, c, -1, SQLITE_STATIC);
  else
    printf ("Failed to execute statement: %s\n", sqlite3_errmsg (db));

  rc = sqlite3_step (stmt);
  if (rc != SQLITE_DONE)
    {
      fprintf (stderr, "Failed to execute statement: %s\n",
               sqlite3_errmsg (db));
    }
  sqlite3_finalize (stmt);
}

GArray *
database_load_categories (sqlite3 *db)
{
  sqlite3_stmt *stmt;

  GArray *categories = g_array_new (TRUE, FALSE, sizeof (category));
  int rc = sqlite3_prepare_v2 (db, "SELECT * FROM categories", -1, &stmt,
                               nullptr);

  if (rc != SQLITE_OK)
    fprintf (stderr, "Failed to execute statement: %s\n", sqlite3_errmsg (db));

  while (sqlite3_step (stmt) == SQLITE_ROW)
    {
      category c;
      c.id = sqlite3_column_int (stmt, 0);
      c.name = strdup ((char *)sqlite3_column_text (stmt, 1));
      g_array_append_val (categories, c);
    }
  sqlite3_finalize (stmt);

  return categories;
}

void
database_delete_category (sqlite3 *db, const int id)
{
  // delete all cards in the category
  sqlite3_stmt *stmt;
  int rc = sqlite3_prepare_v2 (db, "DELETE FROM cards WHERE category = ?", -1,
                               &stmt, nullptr);
  if (rc == SQLITE_OK)
    sqlite3_bind_int (stmt, 1, id);
  else
    fprintf (stderr, "Failed to execute statement: %s\n", sqlite3_errmsg (db));
  rc = sqlite3_step (stmt);
  if (rc != SQLITE_DONE)
    fprintf (stderr, "Execution failed: %s\n", sqlite3_errmsg (db));
  sqlite3_finalize (stmt);

  // delete the category
  rc = sqlite3_prepare_v2 (db, "DELETE FROM categories WHERE id = ?", -1,
                           &stmt, nullptr);
  if (rc == SQLITE_OK)
    sqlite3_bind_int (stmt, 1, id);
  else
    fprintf (stderr, "Failed to execute statement: %s\n", sqlite3_errmsg (db));

  rc = sqlite3_step (stmt);
  if (rc != SQLITE_DONE)
    fprintf (stderr, "Execution failed: %s\n", sqlite3_errmsg (db));
  sqlite3_finalize (stmt);
}

void
database_save_card (sqlite3 *db, const int category, const char *title,
                    const char *answer)
{
  sqlite3_stmt *stmt;

  int rc = sqlite3_prepare_v2 (
      db, "INSERT INTO cards (category, title, answer) VALUES(?, ?, ?)", -1,
      &stmt, nullptr);
  if (rc == SQLITE_OK)
    {
      sqlite3_bind_int (stmt, 1, category);
      sqlite3_bind_text (stmt, 2, title, -1, SQLITE_STATIC);
      sqlite3_bind_text (stmt, 3, answer, -1, SQLITE_STATIC);
    }
  else
    fprintf (stderr, "Failed to execute statement: %s\n", sqlite3_errmsg (db));

  rc = sqlite3_step (stmt);
  if (rc != SQLITE_DONE)
    fprintf (stderr, "Execution failed: %s\n", sqlite3_errmsg (db));
  sqlite3_finalize (stmt);
}

GArray *
database_load_cards (sqlite3 *db, const int category)
{
  GArray *cards = g_array_new (TRUE, FALSE, sizeof (card));

  sqlite3_stmt *stmt;
  int rc
      = sqlite3_prepare_v2 (db,
                            "SELECT * FROM cards WHERE category = ? AND "
                            "next_time <= unixepoch() ORDER BY next_time ASC",
                            -1, &stmt, nullptr);
  if (rc == SQLITE_OK)
    sqlite3_bind_int (stmt, 1, category);
  else
    fprintf (stderr, "Failed to execute statement: %s\n", sqlite3_errmsg (db));

  while (sqlite3_step (stmt) == SQLITE_ROW)
    {
      card c;
      c.id = sqlite3_column_int (stmt, 0);
      c.category = sqlite3_column_int (stmt, 1);
      c.title = strdup ((char *)sqlite3_column_text (stmt, 2));
      c.answer = strdup ((char *)sqlite3_column_text (stmt, 3));
      c.next_time
          = g_date_time_new_from_unix_utc (sqlite3_column_int64 (stmt, 4));

      g_array_append_val (cards, c);
    }
  sqlite3_finalize (stmt);

  return cards;
}

void
database_schedule_card (sqlite3 *db, const int id, GDateTime *next_time)
{
  sqlite3_stmt *stmt;
  int rc = sqlite3_prepare_v2 (
      db, "UPDATE cards SET next_time = ? WHERE id = ?", -1, &stmt, nullptr);
  if (rc == SQLITE_OK)
    {
      sqlite3_bind_int64 (stmt, 1, g_date_time_to_unix (next_time));
      sqlite3_bind_int (stmt, 2, id);
    }
  else
    fprintf (stderr, "Failed to execute statement: %s\n", sqlite3_errmsg (db));

  rc = sqlite3_step (stmt);
  if (rc != SQLITE_DONE)
    fprintf (stderr, "Execution failed: %s\n", sqlite3_errmsg (db));
  sqlite3_finalize (stmt);
}

void
database_delete_card (sqlite3 *db, const int id)
{
  sqlite3_stmt *stmt;
  int rc = sqlite3_prepare_v2 (db, "DELETE FROM cards WHERE id = ?", -1, &stmt,
                               nullptr);
  if (rc == SQLITE_OK)
    sqlite3_bind_int (stmt, 1, id);
  else
    fprintf (stderr, "Failed to execute statement: %s\n", sqlite3_errmsg (db));

  rc = sqlite3_step (stmt);
  if (rc != SQLITE_DONE)
    fprintf (stderr, "Execution failed: %s\n", sqlite3_errmsg (db));
  sqlite3_finalize (stmt);
}