<?php

class RsvMembershipService {

    public function discount_detail_for(RsvFormDefinition $def, RsvFormData $data): array {
        $repo = new RsvMembershipProgramRepository();
        $matched_programs = [];
        $matched_discounts = [];

        foreach ($def->getMembershipBindings() as $binding) {
            $program_id = intval($binding['program_id'] ?? 0);
            $discount   = floatval($binding['discount'] ?? 0.0);
            $field      = strval($binding['field'] ?? '');

            if ($program_id <= 0 || $field === '') {
                continue;
            }

            $raw   = $data->getValue($field, '');
            $value = is_scalar($raw) ? trim((string) $raw) : '';

            if ($value === '') {
                continue;
            }

            if ($repo->key_exists($program_id, $value)) {
                $program = $repo->get($program_id);
                if ($program) {
                    $matched_programs[] = $program['name'];
                }
                $matched_discounts[] = $discount;
            }
        }

        if (empty($matched_discounts)) {
            return ['percent' => 0.0, 'reason' => ''];
        }

        if ($def->getMembershipCombine() === 'sum') {
            $reason = implode(', ', $matched_programs);
            return ['percent' => min(100.0, array_sum($matched_discounts)), 'reason' => $reason];
        }

        $max_idx = array_search(max($matched_discounts), $matched_discounts, true);
        $reason  = $matched_programs[$max_idx] ?? '';
        return ['percent' => max($matched_discounts), 'reason' => $reason];
    }

    /**
     * Total membership discount for a submission.
     *
     * Each binding names a form field whose submitted value must match a key
     * in the bound program. Matching bindings' discounts are combined per the
     * definition's combine mode: the best single discount, or all summed and
     * capped at 100%.
     */
    public function discount_for(RsvFormDefinition $def, RsvFormData $data): float {
        return $this->discount_detail_for($def, $data)['percent'];
    }
}