<?php
namespace DatabaseHelper;

use DatabaseHelper\enums\ColumnTypes;
use InvalidArgumentException;

class Query
{
    private Schema $table;
    private array $columns = ['*'];
    private array $conditions = [];

    public function __construct(Schema $table) {
        $this->table = $table;
    }

    public function select(string ...$cols): Query {
        if (!empty($cols))
            $this->columns = $cols;

        // Validate colum existence
        foreach ($cols as $col)
            if (!$this->table->existsColumn($col))
                throw new InvalidArgumentException("Unknown column: $col");

        return $this;
    }

    public function where(string $col, string $operator, mixed $val): Query {
        return $this->addCondition($col, $operator, $val, "AND");
    }

    public function andWhere(string $col, string $operator, mixed $val): Query {
        return $this->addCondition($col, $operator, $val, "AND");
    }

    public function orWhere(string $col, string $operator, mixed $val): Query {
        return $this->addCondition($col, $operator, $val, "OR");
    }

    private function addCondition(string $col, string $operator, mixed $val, string $prefix): Query {
        if ($this->table->existsColumn($col))
            throw new InvalidArgumentException("Unknown column: $col");

        $columnType = $this->table->columnType($col);
        $castedValue = $columnType->dbCast($val);

        if (!empty($this->conditions))
            $this->conditions[] = $prefix;
        $this->conditions[] = "$col $operator $castedValue";

        return $this;
    }

    public function toSql(): string {
        $columns = implode(", ", $this->columns);
        $table = $this->table->name;
        $whereClause = !empty($this->conditions) ? " WHERE " . implode(" ", $this->conditions) : "";
        return esc_sql("SELECT $columns FROM $table$whereClause");
    }

    public function query(): array {
        global $wpdb;
        $query = $this->toSql();
        $results = $wpdb->get_results($wpdb->prepare($query), ARRAY_A);
        return $this->castResults($results);
    }

    private function castResults(array $results): array {
        foreach ($results as &$row)
            foreach ($row as $column => &$value)
                if (isset($this->columnTypes[$column]))
                    $value = $this->columnTypes[$column]->valCast($value);
        return $results;
    }
}