<?php

namespace NoccyLabs\Dataset;

use Iterator;

class FilteringReaderIterator implements Iterator
{
    private Iterator $reader;

    private $condition;

    /**
     *
     * @note Removed support for callable in cond (php7.4 compat)
     */
    public function __construct(Iterator $reader, array $condition)
    {
        $this->reader = $reader;
        $this->condition = $condition;
    }

    public function current(): mixed
    {
        return $this->reader->current();        
    }

    public function key(): mixed
    {
        return $this->reader->key();        
    }

    public function valid(): bool
    {
        return $this->reader->valid();
    }

    public function next(): void
    {
        $this->reader->next();
        while ($this->reader->valid()) {
            $curr = $this->reader->current();
            if ($this->matchCondition($curr)) 
                break;
            $this->reader->next();
        }        
    }

    public function rewind(): void
    {
        $this->reader->rewind();
        while ($this->reader->valid()) {
            $curr = $this->reader->current();
            if ($this->matchCondition($curr)) 
                break;
            $this->reader->next();
        }
    }

    /**
     * Test a condition against a row
     * 
     * The matched conditions are:
     *   - string/bool/int/float - match value
     *   - array - all conditions in array must match:
     *     - eq     equals
     *     - neq    not equals
     *     - gt     greater than
     *     - gte    greater than or equal
     *     - lt     less than
     *     - in     value in array
     *     - nin    value not in array
     */
    private function matchCondition(array $row): bool
    {
        if (is_callable($this->condition)) {
            return (bool)call_user_func($this->condition, $row);
        }
        foreach ($this->condition as $field=>$test) {
            if (!array_key_exists($field, $row)) continue;
            if (is_array($test)) {
                if (array_key_exists('eq',$test) && $row[$field] != $test['eq']) return false;
                if (array_key_exists('neq',$test) && $row[$field] == $test['neq']) return false;
                if (array_key_exists('gt',$test) && $row[$field] <= $test['gt']) return false;
                if (array_key_exists('gte',$test) && $row[$field] < $test['gte']) return false;
                if (array_key_exists('lt',$test) && $row[$field] >= $test['lt']) return false;
                if (array_key_exists('lte',$test) && $row[$field] > $test['lte']) return false;
                if (array_key_exists('in',$test) && !in_array($row[$field], $test['in'])) return false;
                if (array_key_exists('nin',$test) && in_array($row[$field], $test['in'])) return false;
            } else {
                if ($row[$field] != $test) return false;
            }
        }
        return true;
    }
}