<?php

namespace TCG\Voyager\Database;

use Doctrine\DBAL\Schema\Column;
use Doctrine\DBAL\Schema\SchemaException;
use Doctrine\DBAL\Schema\TableDiff;
use TCG\Voyager\Database\Schema\SchemaManager;
use TCG\Voyager\Database\Schema\Table;
use TCG\Voyager\Database\Types\Type;

class DatabaseUpdater
{
    protected $tableArr;
    protected $table;
    protected $originalTable;

    public function __construct(array $tableArr)
    {
        Type::registerCustomPlatformTypes();

        $this->table = Table::make($tableArr);
        $this->tableArr = $tableArr;
        $this->originalTable = SchemaManager::listTableDetails($tableArr['oldName']);
    }

    /**
     * Update the table.
     *
     * @return void
     */
    public static function update($table)
    {
        if (!is_array($table)) {
            $table = json_decode($table, true);
        }

        if (!SchemaManager::tableExists($table['oldName'])) {
            throw SchemaException::tableDoesNotExist($table['oldName']);
        }

        $updater = new self($table);

        $updater->updateTable();
    }

    /**
     * Updates the table.
     *
     * @return void
     */
    public function updateTable()
    {
        // Get table new name
        if (($newName = $this->table->getName()) != $this->originalTable->getName()) {
            // Make sure the new name doesn't already exist
            if (SchemaManager::tableExists($newName)) {
                throw SchemaException::tableAlreadyExists($newName);
            }
        } else {
            $newName = false;
        }

        // Rename columns
        if ($renamedColumnsDiff = $this->getRenamedColumnsDiff()) {
            SchemaManager::alterTable($renamedColumnsDiff);

            // Refresh original table after renaming the columns
            $this->originalTable = SchemaManager::listTableDetails($this->tableArr['oldName']);
        }

        $tableDiff = $this->originalTable->diff($this->table);

        // Add new table name to tableDiff
        if ($newName) {
            if (!$tableDiff) {
                $tableDiff = new TableDiff($this->tableArr['oldName']);
                $tableDiff->fromTable = $this->originalTable;
            }

            $tableDiff->newName = $newName;
        }

        // Update the table
        if ($tableDiff) {
            SchemaManager::alterTable($tableDiff);
        }
    }

    /**
     * Get the table diff to rename columns.
     *
     * @return \Doctrine\DBAL\Schema\TableDiff
     */
    protected function getRenamedColumnsDiff()
    {
        $renamedColumns = $this->getRenamedColumns();

        if (empty($renamedColumns)) {
            return false;
        }

        $renamedColumnsDiff = new TableDiff($this->tableArr['oldName']);
        $renamedColumnsDiff->fromTable = $this->originalTable;

        foreach ($renamedColumns as $oldName => $newName) {
            $renamedColumnsDiff->renamedColumns[$oldName] = $this->table->getColumn($newName);
        }

        return $renamedColumnsDiff;
    }

    /**
     * Get the table diff to rename columns and indexes.
     *
     * @return \Doctrine\DBAL\Schema\TableDiff
     */
    protected function getRenamedDiff()
    {
        $renamedColumns = $this->getRenamedColumns();
        $renamedIndexes = $this->getRenamedIndexes();

        if (empty($renamedColumns) && empty($renamedIndexes)) {
            return false;
        }

        $renamedDiff = new TableDiff($this->tableArr['oldName']);
        $renamedDiff->fromTable = $this->originalTable;

        foreach ($renamedColumns as $oldName => $newName) {
            $renamedDiff->renamedColumns[$oldName] = $this->table->getColumn($newName);
        }

        foreach ($renamedIndexes as $oldName => $newName) {
            $renamedDiff->renamedIndexes[$oldName] = $this->table->getIndex($newName);
        }

        return $renamedDiff;
    }

    /**
     * Get columns that were renamed.
     *
     * @return array
     */
    protected function getRenamedColumns()
    {
        $renamedColumns = [];

        foreach ($this->tableArr['columns'] as $column) {
            $oldName = $column['oldName'];

            // make sure this is an existing column and not a new one
            if ($this->originalTable->hasColumn($oldName)) {
                $name = $column['name'];

                if ($name != $oldName) {
                    $renamedColumns[$oldName] = $name;
                }
            }
        }

        return $renamedColumns;
    }

    /**
     * Get indexes that were renamed.
     *
     * @return array
     */
    protected function getRenamedIndexes()
    {
        $renamedIndexes = [];

        foreach ($this->tableArr['indexes'] as $index) {
            $oldName = $index['oldName'];

            // make sure this is an existing index and not a new one
            if ($this->originalTable->hasIndex($oldName)) {
                $name = $index['name'];

                if ($name != $oldName) {
                    $renamedIndexes[$oldName] = $name;
                }
            }
        }

        return $renamedIndexes;
    }
}