using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.IO;

namespace MyCustomNamespace {
    class csv_db {
        private object database_lock = new object();
        private string database_path = "";
        private string current_database = "";
        private string current_table = "";
        private ArrayList current_rows = new ArrayList();
        private ArrayList current_indexed_columns = new ArrayList();
        private csv_table_summary current_table_summary;

        public csv_db(string databasePath) {
            try {
                if (!Directory.Exists(databasePath) && databasePath.Length > 0) {
                    Directory.CreateDirectory(databasePath);
                }
                this.database_path = databasePath;
            } catch {
                //Directory creation failed, so just use the current directory.
                this.database_path = "";
            }
        }

        public bool connect(string databaseName) {
            //returns true if database exists, false otherwise
            if (Directory.Exists(this.database_path + "\\" + databaseName)) {
                this.current_database = databaseName;
                this.database_path += "\\" + databaseName;
                return true;
            }
            return false;
        }

        public uint insert(string table, Hashtable rowValues) {
            //returns autoincrement value of new row
            return 0;
        }

        public bool update(string table, uint primaryKey, Hashtable rowValues) {
            //returns true if row updated, false otherwise
            return false;
        }
        public uint update(string table, Hashtable whereValues, Hashtable rowValues) {
            //returns number of rows updated
            return 0;
        }

        public uint query(string table, Hashtable whereValues) {
            //returns number of rows matching query
            return 0;
        }

        public bool delete(string table, uint primaryKey) {
            //returns true if row deleted
            return false;
        }
        public uint delete(string table, Hashtable whereValues) {
            //returns number of rows deleted
            return 0;
        }

        public bool create_db(string databaseName) {
            //returns true if db created
            if (!Directory.Exists(this.database_path + databaseName+"\\")) {
                Directory.CreateDirectory(this.database_path + databaseName + "\\");
                Directory.CreateDirectory(this.database_path + databaseName + "\\_indexes\\");
                Directory.CreateDirectory(this.database_path + databaseName + "\\_table_summary\\");
                return true;
            }
            return false;
        }
        public bool create_db(string databaseName, string sourceDatabaseName) {
            //returns true if db created
            if (this.create_db(this.database_path + databaseName + "\\")) {
                //Now, need to copy files from sourceDatabaseName
            }
            return false;
        }

        public bool create_table(string tableName, ArrayList columns) {
            //returns true if table created
            
            return false;
        }
        public bool create_table(string tableName, ArrayList columns, uint rowLength) {
            //returns true if table created
            if (this.current_database.Length > 0) {
                if (!File.Exists(this.database_path + "\\" + this.current_database + "\\"+tableName + ".csv")) {
                    File.Create(this.database_path + "\\" + tableName + ".csv");
                    this.current_table = tableName;
                    this.current_table_summary = new csv_table_summary(this.database_path, tableName);
                    this.current_table_summary.tableHeaders = columns;
                    this.current_table_summary.rowLength = rowLength;
                    this.save_table_summary();
                    return true;
                }
                return false;
            }
            return false;
        }

        public bool index_insert(string columnName) {
            //returns true if index created
            return false;
        }

        private void load_table_summary() {
            //Loads current table summary into memory for fast access.
            this.current_table_summary = new csv_table_summary(this.database_path, this.current_table);
        }
        private void save_table_summary() {
            FileStream fs = new FileStream(this.database_path + "\\_table_summary\\" + this.current_table + ".csv", FileMode.Create, FileAccess.Write, FileShare.None);
            using (StreamWriter appDataWriter = new StreamWriter(fs)) {
                appDataWriter.WriteLine(this.current_table_summary.nextAutoIncrement);
                appDataWriter.WriteLine(this.current_table_summary.rowLength);
                appDataWriter.WriteLine(this.current_table_summary.tableHeadersString);
                appDataWriter.WriteLine(this.current_table_summary.indexedColumnsString);
            }
        }
    }
    class csv_column {
        private string name = "";
        private Type column_type;
        private uint max_length = 0;

        public csv_column(string columnDetails) {
        }

        public string columnName {
            get {
                return this.name;
            }
        }
        public Type columnType {
            get {
                return this.column_type;
            }
        }
        public uint maxLength {
            get {
                return this.max_length;
            }
        }
    }

    class csv_table_summary {
        private uint row_length = 0;
        private uint next_auto_increment = 0;
        private ArrayList headers = new ArrayList();
        private ArrayList indexed_columns = new ArrayList();

        public csv_table_summary(string database_path,string summaryFileName) {
            //Parse file and populate variables
            if (File.Exists(database_path + "\\_table_summary" + summaryFileName)) {
                using (StreamReader appDataReader = new StreamReader(database_path + "\\_table_summary\\" + summaryFileName + ".csv")) {
                    this.next_auto_increment = Convert.ToUInt32(appDataReader.ReadLine().Trim());
                    this.row_length = Convert.ToUInt32(appDataReader.ReadLine().Trim());
                    this.headers = CSVParser.Parse(appDataReader.ReadLine());
                    this.indexed_columns = CSVParser.Parse(appDataReader.ReadLine());
                }
            }
        }

        public uint rowLength {
            get {
                return this.row_length;
            }
            set {
                this.row_length = value;
            }
        }
        public uint nextAutoIncrement {
            get {
                return this.next_auto_increment;
            }
            set {
                this.next_auto_increment = value;
            }
        }
        public ArrayList tableHeaders {
            get {
                return this.headers;
            }
            set {
                this.headers = value;
            }
        }
        public string tableHeadersString {
            get {
                string rValue = ""; string prefix = "";
                foreach (csv_table_header aHeader in this.headers) {
                    rValue += prefix + aHeader.ToString();
                    prefix = ",";
                }
                return rValue;
            }
        }
        public ArrayList indexedColumns {
            get {
                return this.indexed_columns;
            }
            set {
                this.indexed_columns = value;
            }
        }
        public string indexedColumnsString {
            get {
                string rValue = ""; string prefix = "";
                foreach (string aColumn in this.indexed_columns) {
                    rValue += prefix + aColumn;
                    prefix = ",";
                }
                return rValue;
            }
        }
        public bool isIndexed(string columnName) {
            if (this.indexed_columns.Contains(columnName)) {
                return true;
            } else {
                return false;
            }
        }
    }

    class csv_table_header {
        private string name;
        private string column_type;
        private uint max_length;

        public csv_table_header(string columnName, string columnType, uint maxLength) {
            this.name = columnName;
            this.column_type = columnType;
            this.max_length = maxLength;
        }

        public string columnName {
            set {
                this.name = value;
            }
        }
        public string columnType {
            set {
                this.column_type = value;
            }
        }
        public uint maxLength {
            set {
                this.max_length = value;
            }
        }

        public override string ToString() {
            return this.name + ":" + this.column_type + ":" + this.max_length.ToString();
        }
    }
}