<?php namespace SokoWeb\Database\Query;

use SokoWeb\Interfaces\Database\IConnection;
use SokoWeb\Database\Utils;
use SokoWeb\Interfaces\Database\IAuditLogger;
use SokoWeb\Interfaces\Database\IResultSet;

class Modify
{
    private IConnection $connection;

    private string $table;

    private ?IAuditLogger $auditLogger;

    private string $idName = 'id';

    private array $attributes = [];

    private ?string $externalId = null;

    private bool $autoIncrement = true;

    private ?array $diff = null;

    public function __construct(IConnection $connection, string $table, ?IAuditLogger $auditLogger = null)
    {
        $this->connection = $connection;
        $this->table = $table;
        $this->auditLogger = $auditLogger;
    }

    public function setIdName(string $idName): Modify
    {
        $this->idName = $idName;

        return $this;
    }

    public function setExternalId($id): Modify
    {
        $this->externalId = $id;

        return $this;
    }

    public function setAutoIncrement(bool $autoIncrement = true): Modify
    {
        $this->autoIncrement = $autoIncrement;

        return $this;
    }

    public function fill(array $attributes): Modify
    {
        $this->attributes = array_merge($this->attributes, $attributes);

        return $this;
    }

    public function set(string $name, $value): Modify
    {
        $this->attributes[$name] = $value;

        return $this;
    }

    public function setId($id): Modify
    {
        $this->attributes[$this->idName] = $id;

        return $this;
    }

    public function setDiff(array $diff): Modify
    {
        $this->diff = $diff;

        return $this;
    }

    public function getId()
    {
        return $this->attributes[$this->idName];
    }

    public function save(): void
    {
        if (isset($this->attributes[$this->idName])) {
            $this->update();
        } else {
            $this->insert();
        }
    }

    public function delete(): void
    {
        if (!isset($this->attributes[$this->idName])) {
            throw new \Exception('No primary key specified!');
        }

        $query = 'DELETE FROM ' . Utils::backtick($this->table) . ' WHERE ' . Utils::backtick($this->idName) . '=?';

        $stmt = $this->connection->prepare($query);
        $stmt->execute([$this->idName => $this->attributes[$this->idName]]);

        if ($this->auditLogger !== null) {
            $this->auditLogger->logDelete($this->table, $this->attributes[$this->idName], $this->attributes);
        }
    }

    private function insert(): void
    {
        if ($this->externalId !== null) {
            $this->attributes[$this->idName] = $this->externalId;
        } elseif (!$this->autoIncrement) {
            $this->attributes[$this->idName] = $this->generateKey();
        }

        $set = Utils::generateColumnsWithBinding(array_keys($this->attributes));

        $query = 'INSERT INTO ' . Utils::backtick($this->table) . ' SET ' . $set;

        $stmt = $this->connection->prepare($query);
        $stmt->execute($this->attributes);

        if ($this->autoIncrement) {
            $this->attributes[$this->idName] = $this->connection->lastId();
        }

        if ($this->auditLogger !== null) {
            $this->auditLogger->logInsert($this->table, $this->attributes[$this->idName]);
        }
    }

    private function update(): void
    {
        if ($this->auditLogger !== null) {
            $this->generateDiff();
            if (count($this->diff) === 0) {
                return;
            }
        }

        $attributes = $this->attributes;
        unset($attributes[$this->idName]);

        $set = Utils::generateColumnsWithBinding(array_keys($attributes));

        $query = 'UPDATE ' . Utils::backtick($this->table) . ' SET ' . $set . ' WHERE ' . Utils::backtick($this->idName) . '=?';

        $stmt = $this->connection->prepare($query);
        $stmt->execute(array_merge($attributes, [$this->idName => $this->attributes[$this->idName]]));

        if ($this->auditLogger !== null) {
            $this->auditLogger->logUpdate($this->table, $this->attributes[$this->idName], $this->diff);
        }
    }

    private function generateKey(): string
    {
        return substr(hash('sha256', serialize($this->attributes) . random_bytes(5) . microtime()), 0, 7);
    }

    private function generateDiff(): void
    {
        if (isset($this->diff)) {
            return;
        }

        $this->diff = [];
        $original = $this->readFromDb(array_keys($this->attributes));
        foreach ($original as $key => $value) {
            if ($value !== $this->attributes[$key]) {
                $this->diff[$key] = ['old' => $value, 'new' => $this->attributes[$key]];
            }
        }
    }

    private function readFromDb($columns): array
    {
        return (new Select($this->connection, $this->table))
            ->columns($columns)
            ->where($this->idName, '=', $this->attributes[$this->idName])
            ->execute()
            ->fetch(IResultSet::FETCH_ASSOC);
    }
}