using System;
using System.Collections.Generic;
using System.Data;
using Microsoft.Data.Sqlite;
using 報到系統客戶端.Data;
using 報到系統客戶端.Data.Models;

namespace 報到系統客戶端.Data.Repositories
{
    /// <summary>
    /// Classes 本地資料庫操作類別
    /// </summary>
    public class ClassesRepository
    {
        private readonly DatabaseService _dbService;

        public ClassesRepository()
        {
            _dbService = DatabaseService.Instance;
        }

        /// <summary>
        /// 新增一筆 Classes 資料
        /// </summary>
        public int Insert(LocalClassesItem item)
        {
            try
            {
                var conn = _dbService.GetConnection();
                string sql = @"
                    INSERT INTO Classes 
                    (ID, CourseCode, CourseName, CourseDate, CourseLocation, NotificationTemplate, AgreedTerms, StartTime, EndTime, CreatedAt, UpdatedAt)
                    VALUES (@ID, @CourseCode, @CourseName, @CourseDate, @CourseLocation, @NotificationTemplate, @AgreedTerms, @StartTime, @EndTime, @CreatedAt, @UpdatedAt)
                ";

                using (SqliteCommand cmd = new SqliteCommand(sql, conn))
                {
                    cmd.Parameters.AddWithValue("@ID", item.ID);
                    cmd.Parameters.AddWithValue("@CourseCode", item.CourseCode ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@CourseName", item.CourseName ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@CourseDate", item.CourseDate ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@CourseLocation", item.CourseLocation ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@NotificationTemplate", item.NotificationTemplate ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@AgreedTerms", item.AgreedTerms ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@StartTime", item.StartTime ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@EndTime", item.EndTime ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@CreatedAt", DateTime.Now);
                    cmd.Parameters.AddWithValue("@UpdatedAt", DateTime.Now);

                    cmd.ExecuteNonQuery();
                }

                // 返回傳入的 ID
                return item.ID;
            }
            catch (Exception ex)
            {
                throw new Exception($"新增 Classes 資料失敗：{ex.Message}", ex);
            }
        }

        /// <summary>
        /// 更新一筆 Classes 資料
        /// </summary>
        public bool Update(LocalClassesItem item)
        {
            try
            {
                var conn = _dbService.GetConnection();
                string sql = @"
                    UPDATE Classes SET
                        CourseCode = @CourseCode,
                        CourseName = @CourseName,
                        CourseDate = @CourseDate,
                        CourseLocation = @CourseLocation,
                        NotificationTemplate = @NotificationTemplate,
                        AgreedTerms = @AgreedTerms,
                        StartTime = @StartTime,
                        EndTime = @EndTime,
                        UpdatedAt = @UpdatedAt
                    WHERE ID = @ID
                ";

                using (SqliteCommand cmd = new SqliteCommand(sql, conn))
                {
                    cmd.Parameters.AddWithValue("@ID", item.ID);
                    cmd.Parameters.AddWithValue("@CourseCode", item.CourseCode ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@CourseName", item.CourseName ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@CourseDate", item.CourseDate ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@CourseLocation", item.CourseLocation ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@NotificationTemplate", item.NotificationTemplate ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@AgreedTerms", item.AgreedTerms ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@StartTime", item.StartTime ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@EndTime", item.EndTime ?? (object)DBNull.Value);
                    cmd.Parameters.AddWithValue("@UpdatedAt", DateTime.Now);

                    return cmd.ExecuteNonQuery() > 0;
                }
            }
            catch (Exception ex)
            {
                throw new Exception($"更新 Classes 資料失敗：{ex.Message}", ex);
            }
        }

        /// <summary>
        /// 刪除一筆 Classes 資料
        /// </summary>
        public bool Delete(int id)
        {
            try
            {
                var conn = _dbService.GetConnection();
                string sql = "DELETE FROM Classes WHERE ID = @ID";

                using (SqliteCommand cmd = new SqliteCommand(sql, conn))
                {
                    cmd.Parameters.AddWithValue("@ID", id);
                    return cmd.ExecuteNonQuery() > 0;
                }
            }
            catch (Exception ex)
            {
                throw new Exception($"刪除 Classes 資料失敗：{ex.Message}", ex);
            }
        }

        /// <summary>
        /// 查詢所有 Classes 資料
        /// </summary>
        public List<LocalClassesItem> GetAll()
        {
            return Query("SELECT * FROM Classes ORDER BY ID");
        }

        /// <summary>
        /// 查詢單筆 Classes 資料
        /// </summary>
        public LocalClassesItem GetById(int id)
        {
            var result = Query($"SELECT * FROM Classes WHERE ID = {id}");
            return result.Count > 0 ? result[0] : null;
        }

        /// <summary>
        /// 條件查詢 Classes 資料（分頁）
        /// </summary>
        public List<LocalClassesItem> GetByCondition(int pageIndex, int pageSize, string courseName = "", string courseCode = "", DateTime? startDate = null, DateTime? endDate = null)
        {
            try
            {
                var conn = _dbService.GetConnection();
                string sql = "SELECT * FROM Classes WHERE 1=1";

                if (!string.IsNullOrWhiteSpace(courseCode))
                    sql += " AND CourseCode LIKE '%' || @CourseCode || '%'";

                if (!string.IsNullOrWhiteSpace(courseName))
                    sql += " AND CourseName LIKE '%' || @CourseName || '%'";

                if (startDate.HasValue && endDate.HasValue)
                    sql += " AND CourseDate >= @StartDate AND CourseDate <= @EndDate";
                else if (startDate.HasValue)
                    sql += " AND CourseDate >= @StartDate";
                else if (endDate.HasValue)
                    sql += " AND CourseDate <= @EndDate";

                sql += " ORDER BY CourseDate DESC LIMIT @PageSize OFFSET @Offset";

                List<LocalClassesItem> result = new List<LocalClassesItem>();

                using (SqliteCommand cmd = new SqliteCommand(sql, conn))
                {
                    if (!string.IsNullOrWhiteSpace(courseCode))
                        cmd.Parameters.AddWithValue("@CourseCode", courseCode);

                    if (!string.IsNullOrWhiteSpace(courseName))
                        cmd.Parameters.AddWithValue("@CourseName", courseName);

                    if (startDate.HasValue)
                        cmd.Parameters.AddWithValue("@StartDate", startDate.Value);

                    if (endDate.HasValue)
                        cmd.Parameters.AddWithValue("@EndDate", endDate.Value);

                    cmd.Parameters.AddWithValue("@PageSize", pageSize);
                    cmd.Parameters.AddWithValue("@Offset", (pageIndex - 1) * pageSize);

                    using (SqliteDataReader reader = cmd.ExecuteReader())
                    {
                        while (reader.Read())
                        {
                            result.Add(ReadClassesItem(reader));
                        }
                    }
                }

                return result;
            }
            catch (Exception ex)
            {
                throw new Exception($"查詢 Classes 資料失敗：{ex.Message}", ex);
            }
        }

        /// <summary>
        /// 查詢 Classes 資料總數
        /// </summary>
        public int GetCount(string courseName = "", string courseCode = "", DateTime? startDate = null, DateTime? endDate = null)
        {
            try
            {
                var conn = _dbService.GetConnection();
                string sql = "SELECT COUNT(*) FROM Classes WHERE 1=1";

                if (!string.IsNullOrWhiteSpace(courseCode))
                    sql += " AND CourseCode LIKE '%' || @CourseCode || '%'";

                if (!string.IsNullOrWhiteSpace(courseName))
                    sql += " AND CourseName LIKE '%' || @CourseName || '%'";

                if (startDate.HasValue && endDate.HasValue)
                    sql += " AND CourseDate >= @StartDate AND CourseDate <= @EndDate";
                else if (startDate.HasValue)
                    sql += " AND CourseDate >= @StartDate";
                else if (endDate.HasValue)
                    sql += " AND CourseDate <= @EndDate";

                using (SqliteCommand cmd = new SqliteCommand(sql, conn))
                {
                    if (!string.IsNullOrWhiteSpace(courseCode))
                        cmd.Parameters.AddWithValue("@CourseCode", courseCode);

                    if (!string.IsNullOrWhiteSpace(courseName))
                        cmd.Parameters.AddWithValue("@CourseName", courseName);

                    if (startDate.HasValue)
                        cmd.Parameters.AddWithValue("@StartDate", startDate.Value);

                    if (endDate.HasValue)
                        cmd.Parameters.AddWithValue("@EndDate", endDate.Value);

                    return Convert.ToInt32(cmd.ExecuteScalar());
                }
            }
            catch (Exception ex)
            {
                throw new Exception($"統計 Classes 資料失敗：{ex.Message}", ex);
            }
        }

        /// <summary>
        /// 清除所有 Classes 資料
        /// </summary>
        public void DeleteAll()
        {
            try
            {
                var conn = _dbService.GetConnection();
                using (SqliteCommand cmd = new SqliteCommand("DELETE FROM Classes", conn))
                {
                    cmd.ExecuteNonQuery();
                }
            }
            catch (Exception ex)
            {
                throw new Exception($"清除 Classes 資料失敗：{ex.Message}", ex);
            }
        }

        /// <summary>
        /// 私用方法 - 執行查詢
        /// </summary>
        private List<LocalClassesItem> Query(string sql)
        {
            try
            {
                var conn = _dbService.GetConnection();
                List<LocalClassesItem> result = new List<LocalClassesItem>();

                using (SqliteCommand cmd = new SqliteCommand(sql, conn))
                {
                    using (SqliteDataReader reader = cmd.ExecuteReader())
                    {
                        while (reader.Read())
                        {
                            result.Add(ReadClassesItem(reader));
                        }
                    }
                }

                return result;
            }
            catch (Exception ex)
            {
                throw new Exception($"查詢 Classes 失敗：{ex.Message}", ex);
            }
        }

        /// <summary>
        /// 私用方法 - 讀取資料列
        /// </summary>
        private LocalClassesItem ReadClassesItem(SqliteDataReader reader)
        {
            return new LocalClassesItem
            {
                ID = reader.GetInt32(reader.GetOrdinal("ID")),
                CourseCode = reader.IsDBNull(reader.GetOrdinal("CourseCode")) ? null : reader.GetString(reader.GetOrdinal("CourseCode")),
                CourseName = reader.IsDBNull(reader.GetOrdinal("CourseName")) ? null : reader.GetString(reader.GetOrdinal("CourseName")),
                CourseDate = reader.IsDBNull(reader.GetOrdinal("CourseDate")) ? null : reader.GetString(reader.GetOrdinal("CourseDate")),
                CourseLocation = reader.IsDBNull(reader.GetOrdinal("CourseLocation")) ? null : reader.GetString(reader.GetOrdinal("CourseLocation")),
                NotificationTemplate = reader.IsDBNull(reader.GetOrdinal("NotificationTemplate")) ? null : reader.GetString(reader.GetOrdinal("NotificationTemplate")),
                AgreedTerms = reader.IsDBNull(reader.GetOrdinal("AgreedTerms")) ? null : reader.GetString(reader.GetOrdinal("AgreedTerms")),
                StartTime = reader.IsDBNull(reader.GetOrdinal("StartTime")) ? null : reader.GetString(reader.GetOrdinal("StartTime")),
                EndTime = reader.IsDBNull(reader.GetOrdinal("EndTime")) ? null : reader.GetString(reader.GetOrdinal("EndTime")),
                CreatedAt = reader.GetDateTime(reader.GetOrdinal("CreatedAt")),
                UpdatedAt = reader.GetDateTime(reader.GetOrdinal("UpdatedAt"))
            };
        }
    }
}