using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Dapper;
using Microsoft.Data.Sqlite;
using Serilog;
using SharpRss.Models;

namespace SharpRss.Services
{
    internal class DatabaseService : IDisposable
    {
        private string _connectionString => $"Data Source={Path.Combine(Environment.CurrentDirectory, "sharp_rss.db")};";
        internal DatabaseService()
        {
            _sqlConn = new SqliteConnection(_connectionString);
            InitializeDb();
        }
        private readonly SqliteConnection _sqlConn;

        public async Task<bool> AddCategoriesAsync(HashSet<CategoryModel> categories)
        {
            bool result = true;
            _sqlConn.Open();
            foreach (var categoryModel in categories)
            {
                await _sqlConn.QueryAsync("INSERT INTO category_data (name, hex_color, path_icon, category_id) VALUES(@catName, @hexColor, @pathIcon, @categoryId) ON CONFLICT(name) DO UPDATE SET hex_color=@hexColor, path_icon=@pathIcon",
                    new { catName = categoryModel.Name, hexColor = categoryModel.HexColor, pathIcon = categoryModel.PathIcon, categoryId = categoryModel.CategoryId });
            }
            _sqlConn.Close();
            return result;
        }

        public async Task<bool> AddFeedsAsync(HashSet<FeedModel> feeds)
        {
            bool result = true;
            _sqlConn.Open();
            foreach (var feedModel in feeds)
            {
                await _sqlConn.QueryAsync("INSERT OR REPLACE INTO feed_data(url, feed_id, category_id) VALUES(@url, @feedId, @categoryId) ON CONFLICT(url) DO UPDATE SET category_id=@categoryId", new { url = feedModel.FeedUrl, feedId = feedModel.FeedId, categoryId = feedModel.CategoryId });
            }
            _sqlConn.Close();
            return result;
        }

        public async Task<HashSet<CategoryModel>> GetCategoriesAsync()
        {
            HashSet<CategoryModel> categories = new HashSet<CategoryModel>();
            _sqlConn.Open();
            SqliteCommand cmd = _sqlConn.CreateCommand();
            cmd.CommandText = "SELECT * FROM category_data";
            await using SqliteDataReader reader = await cmd.ExecuteReaderAsync();
            while (reader.Read())
                categories.Add(CategoryModel.Create(reader["name"].ToString(), reader["hex_color"].ToString(), reader["category_id"].ToString()));
            _sqlConn.Close();
            return categories;
        }

        public async Task<HashSet<FeedModel>> GetFeedsAsync(string? categoryId = null)
        {
            HashSet<FeedModel> feeds = new HashSet<FeedModel>();
            _sqlConn.Open();
            
            SqliteCommand cmd = _sqlConn.CreateCommand();
            cmd.CommandText = categoryId == null ? "SELECT * FROM feed_data" : "SELECT * FROM feed_data WHERE category_id=@categoryId";
            if (categoryId != null)
                cmd.Parameters.Add(new SqliteParameter("categoryId", categoryId));

            await using SqliteDataReader reader = await cmd.ExecuteReaderAsync();
            while (reader.Read())
                feeds.Add(FeedModel.Create(reader["url"].ToString(), reader["feed_id"].ToString(), reader["category_id"].ToString()));
            _sqlConn.Close();
            return feeds;
        }

        private async void InitializeDb()
        {
            Log.Verbose("Checking database...");
            _sqlConn.Open();
            var queryResponse = await _sqlConn.QueryAsync("CREATE TABLE IF NOT EXISTS category_data (name STRING NOT NULL, hex_color STRING NOT NULL, path_icon STRING, category_id STRING PRIMARY KEY, CONSTRAINT name UNIQUE (name))");
            if (queryResponse.Any())
            {
                _sqlConn.Close();
                _sqlConn.Dispose();
                throw new SqliteException("Error initializing database!", 0);
            }
            queryResponse = await _sqlConn.QueryAsync("CREATE TABLE IF NOT EXISTS feed_data (url STRING NOT NULL, feed_id STRING PRIMARY KEY, category_id STRING NOT NULL DEFAULT '', CONSTRAINT url, UNIQUE (url))");
            if (queryResponse.Any())
            {
                _sqlConn.Close();
                _sqlConn.Dispose();
                throw new SqliteException("Error initializing database!", 0);
            }
            _sqlConn.Close();
            Log.Verbose("Checking database done!");
        }

        public void Dispose()
        {
            _sqlConn.Dispose();
        }
    }
}