<?php
namespace DatabaseHelper;

use DatabaseHelper\beans\Column;
use DatabaseHelper\beans\Primary;
use DatabaseHelper\beans\Reference;
use DatabaseHelper\beans\Schema;
use DatabaseHelper\enums\Propagation;
use DatabaseHelper\enums\Charset;
use DatabaseHelper\enums\Collation;
use DatabaseHelper\enums\Type;
use DatabaseHelper\enums\Engine;

class Table
{
    protected Schema $schema;

    public function __construct(string $tableName) {
        Database::standardizeTableNames($tableName);
        $this->schema = new Schema($tableName);
    }

    public function column(string $name, Type $type, mixed $default = null, bool $isNullable = false, bool $isUnique = false): Table {
        $col = new Column;
        $col->name = $name;
        $col->default = $default;
        $col->type = $type;
        $col->isUnique = $isUnique;
        $col->isNullable = $isNullable;

        $this->schema->cols[$name] = $col;
        return $this;
    }

    protected function id(): Table {
        $id = new Primary;
        $id->name = $this->schema->name . '_id';
        $this->schema->id = $id;
        return $this;
    }

    public function reference(Schema $foreignTable, Propagation $onDelete = Propagation::CASCADE, Propagation $onUpdate = Propagation::CASCADE): Table {
        $name = $foreignTable->id->name;

        $ref = new Reference;
        $ref->name = $name;
        $ref->otherTable = $foreignTable;
        $ref->onDelete = $onDelete;
        $ref->onUpdate = $onUpdate;

        $this->schema->refs[$name] = $ref;
        return $this;
    }

    public function engine(Engine $engine): Table {
        $this->schema->engine = $engine;
        return $this;
    }

    public function charset(Charset $charset): Table {
        $this->schema->charset = $charset;
        return $this;
    }

    public function collation(Collation $collation): Table {
        $this->schema->collation = $collation;
        return $this;
    }

    public function toSql(): string {
        $primaryKey = $this->schema->id->name;
        $clause = "CREATE TABLE `{$this->schema->name}` (\n";
        $clause .= "  PRIMARY KEY (`$primaryKey`),\n";

        foreach ($this->schema->cols as $col) {
            if ($col->name !== $primaryKey) {
                $clause .= "  `$col->name` {$col->type->toString()}";
                $clause .= !$col->isNullable ? ' NOT NULL' : '';
                $clause .= $col->isUnique ? ' UNIQUE' : '';

                if (!is_null($col->default)) {
                    $default = is_string($col->default) ? "'{$col->default}'" : $col->default;
                    $clause .= " DEFAULT $default";
                }

                $clause .= ",\n";
            }
        }

        // Add foreign keys
        foreach ($this->schema->refs as $ref) {
            $clause .= "  FOREIGN KEY (`{$ref->name}`)";
            $clause .= " REFERENCES `{$ref->otherTable->name}` (`{$ref->name}`)";
            $clause .= " ON DELETE {$ref->onDelete->toString()}";
            $clause .= " ON UPDATE {$ref->onUpdate->toString()},\n";
        }

        // Close the SQL string and add constraints
        $clause = rtrim($clause, ",\n") . "\n) ";
        $clause .= "ENGINE={$this->schema->engine->toString()} ";
        $clause .= "CHARSET={$this->schema->charset->toString()} ";
        $clause .= "COLLATE={$this->schema->collation->toString()};";
        return $clause;
    }

    public function create(): Schema {
        global $wpdb;
        $this->id();

        Database::standardizeTableNames($this->schema->name);
        $tableName = $this->schema->name;

        $foundTables = $wpdb->get_var("SHOW TABLES LIKE '$tableName'");
        if (is_null($foundTables)) {
            $sql = $this->toSql();
            require_once(ABSPATH . 'wp-admin/includes/upgrade.php');
            dbDelta($sql);
        }
        return $this->schema;
    }
}