#!/usr/bin/php
<?php

/**
 * DomFramework
 * @package domframework
 * @author Dominique Fournier <dominique@fournier38.fr>
 *
 * SQL Migrate
 * This tool allow to migrate the data from one SQL database to another.
 * The DB engine can also be different.
 *
 * You must have the source DB and create a target DB with all the destination
 * tables available.
 * You must pass one parameter : the configuration file where all the
 * informations will be stored. The file will be created if it doesn't exists.
 */

require_once(__DIR__ . "/../src/Console.php");
require_once(__DIR__ . "/../src/Dblayeroo.php");
require_once(__DIR__ . "/../src/Getopts.php");
require_once(__DIR__ . "/../src/Config.php");

/**
 * Manage the configuration file
 */
class Configuration extends \Domframework\Config
{
    /**
     * The constructor of the configuration set the differents params
     */
    public function __construct()
    {
        $this->default = [
          "db" => [
            "srcDSN" => "",
            "srcUser" => null,
            "srcPassword" => null,
            "dstDSN" => "",
            "dstUser" => null,
            "dstPassword" => null,
          ],
          "tables" => [
          ],
          "tablesRel" => [
          ],
          "fields" => [
          ],
          "tablesOrder" => [
          ],
          "deleteContent" => null,
        ];
    }
}

/**
 * The main class
 */
class Main
{
    /**
     * The constructor of the class do the main job
     */
    public function __construct()
    {
        // Manage the Getopts
        $getopts = new Domframework\Getopts();
        $getopts->add("Help", "?h", ["help"], "Help of the software");
        $getopts->add(
            "Step",
            "",
            ["step:"],
            "Restart at provided step",
            "StepIdentifier"
        );
        $getopts->add("Debug", "", ["debug"], "Display the SQL requests");
        $getopts->add(
            "Execute",
            "",
            ["execute"],
            "Execute the configuration without requesting data (start at step 5)"
        );
        if ($getopts->get("Help")) {
            die($getopts->help());
        }
        if ($getopts->get("Step")) {
            if (
                intval($getopts->get("Step")) < 0 ||
                intval($getopts->get("Step")) > 6
            ) {
                die("Invalid Step provided (Must be between 0 and 6)\n");
            }
        }
        if (empty($getopts->restOfLine())) {
            throw new \Exception("No configuration file provided");
        }
        if (count($getopts->restOfLine()) > 1) {
            throw new \Exception("Too much configuration file provided");
        }
        $configurationFile = current($getopts->restOfLine());
        if (! file_exists($configurationFile)) {
            touch($configurationFile);
        }
        $config = new Domframework\Configuration();
        $config->confFile = $configurationFile;

        $db = $config->get("db");
        $tables = $config->get("tables");
        $tablesRel = $config->get("tablesRel");
        $fields = $config->get("fields");
        $tablesOrder = $config->get("tablesOrder");
        $deleteContent = $config->get("deleteContent");
        if ($db["srcDSN"] === "" || $db["dstDSN"] === "") {
            $step = 0;
        } elseif (empty($tables)) {
            $step = 1;
        } elseif (empty($tablesRel)) {
            $step = 2;
        } elseif (empty($fields)) {
            $step = 3;
        } elseif (empty($tablesOrder)) {
            $step = 4;
        } elseif ($deleteContent === null) {
            $step = 5;
        } else {
            $step = 6;
        }

        if ($getopts->get("Step")) {
            $step = intval($getopts->get("Step"));
        }
        if ($getopts->get("Execute")) {
            $step = 5;
        }

        if ($step === 0) {
            // Step 0: ask the connection parameters
            echo "#### Entering step 0 : ask the connection parameters\n";
            $srcDSN = $this->ask("Enter SRC DSN");
            $srcUser = $this->ask("Enter SRC User");
            $srcPassword = $this->ask("Enter SRC Password");
            $dstDSN = $this->ask("Enter DST DSN");
            $dstUser = $this->ask("Enter DST User");
            $dstPassword = $this->ask("Enter DST Password");
            if ($srcUser === "") {
                $srcUser = null;
                $srcPassword = null;
            }
            if ($dstUser === "") {
                $dstUser = null;
                $dstPassword = null;
            }
            $value = [
              "srcDSN" => $srcDSN,
              "srcUser" => $srcUser,
              "srcPassword" => $srcPassword,
              "dstDSN" => $dstDSN,
              "dstUser" => $dstUser,
              "dstPassword" => $dstPassword,];
            $config->set("db", $value);
            $db = $config->get("db");
            $step++;
        }
        if ($step === 1) {
            echo "#### Entering step 1: read the existing databases schemes\n";
            $srcDB = new Domframework\Dblayeroo(
                $db["srcDSN"],
                $db["srcUser"],
                $db["srcPassword"]
            );
            $srcTables = $srcDB->listTables();
            $dstDB = new Domframework\Dblayeroo(
                $db["dstDSN"],
                $db["dstUser"],
                $db["dstPassword"]
            );
            $dstTables = $dstDB->listTables();
            $value = [
              "srcTables" => $srcTables,
              "dstTables" => $dstTables,
            ];
            $config->set("tables", $value);
            $step++;
            echo "\n";
        }

        echo "#### Connect to the defined databases\n";
        $srcDB = new Domframework\Dblayeroo(
            $db["srcDSN"],
            $db["srcUser"],
            $db["srcPassword"]
        );
        $dstDB = new Domframework\Dblayeroo(
            $db["dstDSN"],
            $db["dstUser"],
            $db["dstPassword"]
        );
        echo "\n";

        if ($step == 2) {
            echo "#### Entering step 2: ask the relations between tables\n";
            $tables = $config->get("tables");
            echo "# For each destination table, please provide the source table\n";
            sort($tables["srcTables"]);
            echo "# Allowed source tables : " . implode(", ", $tables["srcTables"]) .
              "\n";
            $value = [];
            natsort($tables["dstTables"]);
            foreach ($tables["dstTables"] as $table) {
                while (1) {
                    $value[$table] = $this->ask(
                        "Destination Table '$table' filled by source table"
                    );
                    if (
                        in_array($value[$table], $tables["srcTables"]) ||
                        $value[$table] === ""
                    ) {
                        continue 2;
                    }
                    $this->error("The table '" . $value[$table] . " doesn't exists");
                    echo "# Allowed source tables : " .
                         implode(", ", $tables["srcTables"]) . "\n";
                }
            }
            $config->set("tablesRel", $value);
            $step++;
            echo "\n";
        }

        $tablesRel = $config->get("tablesRel");
        if ($step === 3) {
            echo "#### Entering step 3: ask the relation between fields\n";
            echo "# For each destination table, if a source table is provided,\n" .
                 "# for each field, provide the source SQL request (can be field,\n" .
                 "# CONCAT(), text between simple quotes, null...)\n";
            if ($config->get("fields")) {
                $value = $config->get("fields");
            } else {
                $value = [];
            }
            foreach ($tablesRel as $dstTable => $srcTable) {
                echo "- Destination Table '$dstTable': ";
                if ($srcTable === "") {
                    echo "No source table. SKIPPED\n";
                    continue;
                }
                echo "\n";
                $dstSchema = $dstDB->getTableSchema($dstTable);
                $srcSchema = $srcDB->getTableSchema($srcTable);
                echo "  List of the allowed fields: " .
                  implode(", ", array_keys($srcSchema["fields"])) . "\n";
                foreach (array_keys($dstSchema["fields"]) as $field) {
                    if (! key_exists($dstTable, $value)) {
                        $value[$dstTable] = [];
                    }
                    if (! key_exists($field, $value[$dstTable])) {
                        $value[$dstTable][$field] = "";
                    }
                    while (1) {
                        $oldval = (isset($config->get("fields")[$dstTable][$field])) ?
                           $config->get("fields")[$dstTable][$field] : "";
                        $answer = $this->ask(
                            "Destination Table '$dstTable' field '$field'",
                            $oldval
                        );
                        $value[$dstTable][$field] = $answer;
                        if (trim($value[$dstTable][$field]) !== "") {
                            break;
                        }
                        // TODO : Check if the field is valid (think about function)
                        $this->error("The field source must be defined !");
                    }
                }
                $config->set("fields", $value);
            }
            $step++;
            echo "\n";
        }
        $fields = $config->get("fields");
        if ($step === 4) {
            echo "#### Entering step 4: Order the tables by foreign keys\n";
            echo "# The tables with foreign keys constraint must be populated \n" .
                 "# after the tables depending of them\n";
            $tablesToOrder = [];
            foreach ($tablesRel as $dstTable => $srcTable) {
                if ($srcTable !== "") {
                    $tablesToOrder[] = $dstTable;
                }
            }
            while (1) {
                echo "# Here are the tables to order: " . implode(",", $tablesToOrder) .
                     "\n";
                $tablesOrder = $this->ask("Order the tables, separated by commas");
                $tablesOrder = explode(",", $tablesOrder);
                if (count($tablesToOrder) === count($tablesOrder)) {
                    break;
                }
                $this->error("Not all the tables are ordered");
            }
            $config->set("tablesOrder", $tablesOrder);
            $step++;
            echo "\n";
        }

        $tablesOrder = $config->get("tablesOrder");
        if ($step === 5) {
            if ($deleteContent === null) {
                echo "# The content of the destination tables can be deleted before\n" .
                     "# adding the source data.\n";
                echo "# Attention: the order is important if there is foreign keys!\n" .
                     "# Remove the most constraint tables before deleting the less\n" .
                     "# constraint ones\n";
                echo "# List of the destination tables: " .
                     implode(",", array_keys(array_diff($tablesRel, [""]))) .
                     "\n";
                $deleteContent = $this->ask("Get the list of the tables to be " .
                                             "cleaned, separated by comas");
                $config->set("deleteContent", $deleteContent);
                $deleteContent = $config->get("deleteContent");
            }
        }
        if ($deleteContent !== "") {
            echo "#### Entering step 5: delete tables content\n";
            foreach (explode(",", $deleteContent) as $table) {
                $table = trim($table);
                echo "- Delete content of table '$table'\n";
                $dstDB->table($table)->unique([])->delete()->execute();
            }
            $step = 6;
            echo "\n";
        } else {
            echo "#### Entering step5: Skipped delete tables content\n";
            $step = 6;
        }
        if ($step === 6) {
            echo "#### Entering step 6: populate the destination database with the " .
                 "configured data\n";
            foreach ($tablesOrder as $dstTable) {
                echo "- Populate table $dstTable:\n";
                // Create the source SQL request. Add the alias name of the destination
                // table to allow to import directely in the destination
                $sql = "SELECT ";
                $i = 0;
                foreach ($fields[$dstTable] as $key => $val) {
                    if ($i > 0) {
                        $sql .= ",";
                    }
                    $sql .= "$val AS $key";
                    $i++;
                }
                $sql .= " FROM " . $tablesRel[$dstTable];
                echo "    $sql\n";
                echo "    ";
                // Define all the variables needed to insert
                $dstSchema = $dstDB->getTableSchema($dstTable);
                $dstDB->table($dstTable);
                $dstDB->fields($dstSchema["fields"]);
                $dstDB->primary($dstSchema["primary"]);
                foreach ($srcDB->directQuery($sql) as $row) {
                    //print_r ($row);
                    $dstDB->clearRequest();
                    $dstDB->insert()
                          ->setValues($row);
                    if (! $getopts->get("Debug")) {
                        echo ".";
                    } else {
                        echo $dstDB->getDisplayQuery();
                    }
                    $dstDB->execute();
                }
                echo "\n";
            }
            $step++;
        }
        // Last step
        echo "#### Entering step $step: End of process\n";
    }

    /**
     * Ask a question to the user and return the answer
     * @param string $question the question message
     * @param string|null $proposal The optional pre-filled proposal
     * @return string The answer
     */
    public function ask($question, $proposal = "")
    {
        $console = new Domframework\Console();
        $console->echo("$question: ");
        return trim($console->readline($proposal));
    }

    /**
     * Display an error to the user
     * @param string $msg The error message to display
     */
    public function error($msg)
    {
        file_put_contents("php://stderr", "ERROR: " . $msg . "\n");
    }
}

try {
    $main = new \main();
} catch (Exception $e) {
    file_put_contents("php://stderr", $e->getMessage() . "\n");
    exit(4);
}