using System;
using System.Text;
using Microsoft.Extensions.Logging;
using Microsoft.EntityFrameworkCore;
using AyaNova.Models;

namespace AyaNova.Util
{

    //Key generator controller
    public static class AySchema
    {
        private static ILogger log;
        private static AyContext ct;




        /////////////////////////////////////////////////////////////////
        /////////// CHANGE THIS ON NEW SCHEMA UPDATE ////////////////////

        //!!!!WARNING: BE SURE TO UPDATE THE DbUtil::EmptyBizDataFromDatabaseForSeedingOrImporting WHEN NEW TABLES ADDED!!!!
        private const int DESIRED_SCHEMA_LEVEL = 9;

        internal const long EXPECTED_COLUMN_COUNT = 99;
        internal const long EXPECTED_INDEX_COUNT = 26;

        //!!!!WARNING: BE SURE TO UPDATE THE DbUtil::EmptyBizDataFromDatabaseForSeedingOrImporting WHEN NEW TABLES ADDED!!!!

        /////////////////////////////////////////////////////////////////


        /*

        MAXIMUM POSTGRES OBJECT NAME LENGTH: 63 CHARACTERS

        HOW TO INDEX

        AyaNova does a lot of name fetching so any tables that contain a lot of columns in addition to the name will benefit from a compound index on (id,name)

        Other indexes should be created with care and after a huge load and integration test periodically look for unused indexes and see how they are performing
        see core-performance.txt for the relevant queries to view this info

        *****************************  WARNING: Be careful here, if a standard field is hideable and also it's DB SCHEMA is  set to NON NULLABLE then the CLIENT end needs to set a default
        *****************************  Otherwise the hidden field can't be set and the object can't be saved EVER

         */

        static int startingSchema = -1;
        public static int currentSchema = -1;



        //check and update schema
        public static void CheckAndUpdate(AyContext context, ILogger logger)
        {
            ct = context;
            log = logger;

            //Check if ayschemaversion table exists
            bool aySchemaVersionExists = false;

            using (var command = ct.Database.GetDbConnection().CreateCommand())
            {
                command.CommandText = "SELECT * FROM information_schema.tables WHERE table_name = 'aschemaversion'";
                ct.Database.OpenConnection();
                using (var result = command.ExecuteReader())
                {
                    if (result.HasRows)
                    {
                        aySchemaVersionExists = true;
                    }
                    ct.Database.CloseConnection();
                }
            }


            //Create schema table (v1)
            if (!aySchemaVersionExists)
            {
                log.LogDebug("aschemaversion table not found, creating now");
                //nope, no schema table, add it now and set to v1
                using (var cm = ct.Database.GetDbConnection().CreateCommand())
                {
                    ct.Database.OpenConnection();
                    cm.CommandText = "CREATE TABLE aschemaversion (schema INTEGER NOT NULL);";
                    cm.ExecuteNonQuery();

                    cm.CommandText = "insert into aschemaversion (schema) values (1);";
                    cm.ExecuteNonQuery();

                    ct.Database.CloseConnection();
                    startingSchema = 1;
                    currentSchema = 1;
                }
            }
            else
            {
                //get current schema level
                using (var cm = ct.Database.GetDbConnection().CreateCommand())
                {
                    log.LogDebug("Fetching current schema version");
                    cm.CommandText = "SELECT schema FROM aschemaversion;";
                    ct.Database.OpenConnection();
                    using (var result = cm.ExecuteReader())
                    {
                        if (result.HasRows)
                        {
                            result.Read();
                            currentSchema = startingSchema = result.GetInt32(0);
                            ct.Database.CloseConnection();
                            log.LogDebug("AyaNova schema version is " + currentSchema.ToString());
                        }
                        else
                        {
                            ct.Database.CloseConnection();
                            throw new System.Exception("AyaNova->AySchema->CheckAndUpdate: Error reading schema version");
                        }
                    }
                }
            }

            //Bail early no update?
            if (currentSchema == DESIRED_SCHEMA_LEVEL)
            {
                log.LogDebug("Current schema is at required schema version " + currentSchema.ToString());
                return;
            }

            log.LogInformation("AyaNova database needs to be updated from schema version {0} to version {1}", currentSchema, DESIRED_SCHEMA_LEVEL);

            //************* SCHEMA UPDATES ******************

            //////////////////////////////////////////////////           
            // FOUNDATIONAL TABLES
            //
            if (currentSchema < 2)
            {
                LogUpdateMessage(log);

                //create aevent biz event log table
                exec("CREATE TABLE aevent (id BIGSERIAL PRIMARY KEY, created timestamp not null, userid bigint not null," +
                "ayid bigint not null, aytype integer not null, ayevent integer not null, textra varchar(255))");

                //SEARCH TABLES
                exec("CREATE TABLE asearchdictionary (id BIGSERIAL PRIMARY KEY, word varchar(255) not null)");

                //Search dictionary words must be unique
                exec("CREATE UNIQUE INDEX asearchdictionary_word_idx ON asearchdictionary (word);");

                exec("CREATE TABLE asearchkey (id BIGSERIAL PRIMARY KEY, wordid bigint not null REFERENCES asearchdictionary (id), objectid bigint not null, objecttype integer not null, inname bool not null)");

                //create locale text tables
                exec("CREATE TABLE alocale (id BIGSERIAL PRIMARY KEY, name varchar(255) not null, stock bool, cjkindex bool default false)");
                //LOOKAT: I don't think this is doing anything:
                //exec("CREATE UNIQUE INDEX alocale_name_idx ON alocale (name)");

                exec("CREATE TABLE alocaleitem (id BIGSERIAL PRIMARY KEY, localeid bigint not null REFERENCES alocale (id), key text not null, display text not null)");

                //LOOKAT: this is for what exactly??
                // exec("CREATE INDEX alocaleitem_localeid_key_idx ON alocaleitem (localeid,key)");
                //This seems more appropriate
                exec("CREATE INDEX alocaleitem_localeid_key_display_idx ON alocaleitem (localeid,key, display)");

                //Load the default LOCALES
                AyaNova.Biz.PrimeData.PrimeLocales();


                //Add user table
                exec("CREATE TABLE auser (id BIGSERIAL PRIMARY KEY, active bool not null, name varchar(255) not null, " +
                "login text not null, password text not null, salt text not null, roles integer not null, localeid bigint not null REFERENCES alocale (id), " +
                "dlkey text, dlkeyexpire timestamp, usertype integer not null, employeenumber varchar(255), notes text, customerid bigint, " +
                "headofficeid bigint, subvendorid bigint, customfields text, tags varchar(255) ARRAY)");

                //Index for name fetching
                exec("CREATE UNIQUE INDEX auser_name_id_idx ON auser (id, name);");

                //Add user options table
                exec("CREATE TABLE auseroptions (id BIGSERIAL PRIMARY KEY, " +
                "userid bigint not null, timezoneoffset decimal(19,5) not null default 0, emailaddress text, uicolor int not null default 0)");


                //Prime the db with the default MANAGER account
                AyaNova.Biz.PrimeData.PrimeManagerAccount(ct);

                setSchemaLevel(++currentSchema);
            }


            //////////////////////////////////////////////////           
            //LICENSE table
            if (currentSchema < 3)
            {
                LogUpdateMessage(log);

                //Add user table
                exec("CREATE TABLE alicense (id BIGSERIAL PRIMARY KEY, dbid uuid, key text not null)");

                setSchemaLevel(++currentSchema);
            }


            //////////////////////////////////////////////////           
            //WIDGET table for development testing
            if (currentSchema < 4)
            {
                LogUpdateMessage(log);

                //Add widget table
                //id, text, longtext, boolean, currency,
                exec("CREATE TABLE awidget (id BIGSERIAL PRIMARY KEY, name varchar(255) not null, serial bigint not null," +
                "startdate timestamp, enddate timestamp, dollaramount decimal(19,5), active bool, roles int4, count integer," +
                "notes text, userid bigint null, customfields text, tags varchar(255) ARRAY)");

                //TEST TEST TEST ONLY FOR DEVELOPMENT TESTING TO ENSURE UNIQUENESS
                //exec("CREATE UNIQUE INDEX awidget_serial_idx ON awidget (serial);");


                //Compound index for name fetching
                exec("CREATE UNIQUE INDEX awidget_name_id_idx ON awidget (id, name);");

                //Index for tags
                exec("CREATE INDEX awidget_tags ON AWIDGET using GIN(tags)");

                setSchemaLevel(++currentSchema);
            }


            //////////////////////////////////////////////////           
            // FileAttachment table
            if (currentSchema < 5)
            {
                LogUpdateMessage(log);

                exec("CREATE TABLE afileattachment (id BIGSERIAL PRIMARY KEY, " +
                "attachtoobjectid bigint not null, attachtoobjecttype integer not null, " +
                "storedfilename text not null, displayfilename text not null, contenttype text, notes text)");

                //index required for ops that need to check if file already in db (delete, count refs etc)
                //LOOKAT: isn't this useless without the ID as well or is that not fetched?
                exec("CREATE INDEX afileattachment_storedfilename_idx ON afileattachment (storedfilename);");

                setSchemaLevel(++currentSchema);
            }




            //////////////////////////////////////////////////           
            // OPS LRO tables
            if (currentSchema < 6)
            {
                LogUpdateMessage(log);

                exec("CREATE TABLE aopsjob (gid uuid PRIMARY KEY, name text not null, created timestamp not null, exclusive bool not null, " +
                "startafter timestamp not null, jobtype integer not null, objectid bigint null, objecttype integer null, jobstatus integer not null, jobinfo text null)");
                exec("CREATE TABLE aopsjoblog (gid uuid PRIMARY KEY, jobid uuid not null REFERENCES aopsjob (gid), created timestamp not null, statustext text not null)");

                setSchemaLevel(++currentSchema);
            }


            //////////////////////////////////////////////////           
            //DATAFILTER / DATALISTTEMPLATE tables
            if (currentSchema < 7)
            {
                LogUpdateMessage(log);

                exec("CREATE TABLE adatalistfilter (id BIGSERIAL PRIMARY KEY, userId bigint not null, name varchar(255) not null,  public bool not null," +
                "listkey varchar(255) not null, filter text, sort text, UNIQUE(name))");

                exec("CREATE TABLE adatalisttemplate (id BIGSERIAL PRIMARY KEY, datalistkey text not null, template text, UNIQUE(datalistkey))");
                setSchemaLevel(++currentSchema);
            }


            //////////////////////////////////////////////////           
            // TAGS repository      
            if (currentSchema < 8)
            {
                LogUpdateMessage(log);
                exec("CREATE TABLE atag (id BIGSERIAL PRIMARY KEY, name varchar(255) not null, refcount bigint not null, UNIQUE(name))");
                setSchemaLevel(++currentSchema);
            }



            //////////////////////////////////////////////////           
            //FORMCUSTOM table
            if (currentSchema < 9)
            {
                LogUpdateMessage(log);

                exec("CREATE TABLE aformcustom (id BIGSERIAL PRIMARY KEY, " +
                "formkey varchar(255) not null, template text, UNIQUE(formkey))");
                setSchemaLevel(++currentSchema);
            }


            //MAKE SURE THE DESIRED SCHEMA WAS SET PROPERLY
            if (currentSchema > DESIRED_SCHEMA_LEVEL)
                throw new ArgumentOutOfRangeException("AySchema::DesiredSchemaLevel WASN'T SET PROPERLY");



            //#########################################
            //!!!!WARNING: BE SURE TO UPDATE THE DbUtil::EmptyBizDataFromDatabaseForSeedingOrImporting WHEN NEW TABLES ADDED!!!!

            //////////////////////////////////////////////////           
            // FUTURE       
            // if (currentSchema < 10)
            // {
            //     LogUpdateMessage(log);

            //     setSchemaLevel(++currentSchema);
            // }






            log.LogInformation("Finished updating database schema to version {0}", currentSchema);
            //*************************************************************************************



        }//eofunction



        private static void setSchemaLevel(int nCurrentSchema)
        {
            exec("UPDATE aschemaversion SET schema=" + nCurrentSchema.ToString());
        }

        //execute command query
        private static void exec(string q)
        {
            using (var cm = ct.Database.GetDbConnection().CreateCommand())
            {
                ct.Database.OpenConnection();
                cm.CommandText = q;
                cm.ExecuteNonQuery();
                ct.Database.CloseConnection();
            }
        }


        private static void LogUpdateMessage(ILogger log)
        {
            log.LogDebug($"Updating database to schema version {currentSchema + 1}");
        }


        //eoclass
    }
    //eons
}