<?php
namespace DatabaseHelper;

use InvalidArgumentException;

class Insertion
{
    private Schema $table;
    private array $currentRow = [];
    private array $batchRows = [];

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

    /**
     * Adds a single column-value pair to the row.
     * @param string $col Column name.
     * @param mixed $val Value to insert.
     * @return Insertion Current instance for method chaining.
     * @throws InvalidArgumentException
     */
    public function data(string $col, mixed $val): Insertion {
        if (!isset($this->table->columns[$col]))
            throw new InvalidArgumentException("Column '$col' does not exist.");

        $columnType = $this->table->columns[$col]['colType'];
        $this->currentRow[$col] = $columnType->dbCast($val);

        return $this;
    }

    /**
     * Adds multiple column-value pairs to the row.
     * @param array $data Associative array of column-value pairs.
     * @return Insertion Current instance for method chaining.
     * @throws InvalidArgumentException
     */
    public function batchData(array $data): Insertion {
        foreach ($data as $key => $value)
            $this->data($key, $value);
        return $this;
    }

    /**
     * Finalizes the current row and stacks it for insertion.
     * @return Insertion Current instance for method chaining.
     */
    public function stack(): Insertion {
        if (!empty($this->currentRow))
            $this->stackForInsertion();
        return $this;
    }

    private function stackForInsertion(): void {
        $this->batchRows[] = $this->currentRow;
        $this->currentRow = [];
    }

    /**
     * Executes the insertion of all batched rows into the database.
     * @throws InvalidArgumentException
     */
    public function insert(): void {
        global $wpdb;

        // Convert single to batch queries.
        if (!empty($this->currentRow))
            $this->stackForInsertion();

        if (empty($this->batchRows))
            throw new InvalidArgumentException("No data set for insertion.");

        foreach ($this->batchRows as $row)
            if (!empty($row))
                $wpdb->insert($this->table->name, $row);
    }
}