<?php

require_once __DIR__ . '/db.php';
require_once __DIR__ . '/helpers.php';

/*
테이블 필요

CREATE TABLE IF NOT EXISTS user_transaction_defaults (
    user_id BIGINT UNSIGNED NOT NULL PRIMARY KEY,
    default_account_id BIGINT UNSIGNED DEFAULT NULL,
    default_card_account_id BIGINT UNSIGNED DEFAULT NULL,
    default_income_category_id BIGINT UNSIGNED DEFAULT NULL,
    default_expense_category_id BIGINT UNSIGNED DEFAULT NULL,
    default_transfer_category_id BIGINT UNSIGNED DEFAULT NULL,
    default_card_payment_category_id BIGINT UNSIGNED DEFAULT NULL,
    keep_last_values TINYINT(1) NOT NULL DEFAULT 1,
    continue_after_save TINYINT(1) NOT NULL DEFAULT 1,
    quick_amounts VARCHAR(255) DEFAULT NULL,
    updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
        ON UPDATE CURRENT_TIMESTAMP
);
*/

function get_transaction_form_defaults(int $userId): array
{
    $pdo = db();

    $stmt = $pdo->prepare("
        SELECT *
        FROM user_transaction_defaults
        WHERE user_id = ?
        LIMIT 1
    ");
    $stmt->execute([$userId]);

    $row = $stmt->fetch();

    if (!$row) {
        return get_transaction_form_default_seed();
    }

    $row['keep_last_values'] = (int)$row['keep_last_values'];
    $row['continue_after_save'] = (int)$row['continue_after_save'];
    $row['quick_amounts'] = parse_quick_amounts($row['quick_amounts'] ?? '');

    return array_merge(get_transaction_form_default_seed(), $row);
}

function get_transaction_form_default_seed(): array
{
    return [
        'default_account_id' => null,
        'default_card_account_id' => null,

        'default_income_category_id' => null,
        'default_expense_category_id' => null,
        'default_transfer_category_id' => null,
        'default_card_payment_category_id' => null,

        'keep_last_values' => 1,
        'continue_after_save' => 1,

        'quick_amounts' => [10000, 30000, 50000, 100000],
    ];
}

function save_transaction_form_defaults(int $userId, array $data): void
{
    $pdo = db();

    $quickAmounts = normalize_quick_amounts(
        $data['quick_amounts'] ?? []
    );

    $stmt = $pdo->prepare("
        INSERT INTO user_transaction_defaults
        (
            user_id,
            default_account_id,
            default_card_account_id,
            default_income_category_id,
            default_expense_category_id,
            default_transfer_category_id,
            default_card_payment_category_id,
            keep_last_values,
            continue_after_save,
            quick_amounts
        )
        VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
        ON DUPLICATE KEY UPDATE
            default_account_id = VALUES(default_account_id),
            default_card_account_id = VALUES(default_card_account_id),
            default_income_category_id = VALUES(default_income_category_id),
            default_expense_category_id = VALUES(default_expense_category_id),
            default_transfer_category_id = VALUES(default_transfer_category_id),
            default_card_payment_category_id = VALUES(default_card_payment_category_id),
            keep_last_values = VALUES(keep_last_values),
            continue_after_save = VALUES(continue_after_save),
            quick_amounts = VALUES(quick_amounts)
    ");

    $stmt->execute([
        $userId,

        nullable_id($data['default_account_id'] ?? null),
        nullable_id($data['default_card_account_id'] ?? null),

        nullable_id($data['default_income_category_id'] ?? null),
        nullable_id($data['default_expense_category_id'] ?? null),
        nullable_id($data['default_transfer_category_id'] ?? null),
        nullable_id($data['default_card_payment_category_id'] ?? null),

        !empty($data['keep_last_values']) ? 1 : 0,
        !empty($data['continue_after_save']) ? 1 : 0,

        implode(',', $quickAmounts),
    ]);
}

function nullable_id($value): ?int
{
    $v = (int)$value;

    return $v > 0 ? $v : null;
}

function parse_quick_amounts(string $csv): array
{
    if (trim($csv) === '') {
        return [10000, 30000, 50000, 100000];
    }

    $items = explode(',', $csv);
    $result = [];

    foreach ($items as $item) {
        $v = (int)trim($item);
        if ($v > 0) {
            $result[] = $v;
        }
    }

    if (!$result) {
        return [10000, 30000, 50000, 100000];
    }

    return array_values(array_unique($result));
}

function normalize_quick_amounts(array $items): array
{
    $result = [];

    foreach ($items as $item) {
        $v = (int)$item;
        if ($v > 0) {
            $result[] = $v;
        }
    }

    if (!$result) {
        $result = [10000, 30000, 50000, 100000];
    }

    $result = array_values(array_unique($result));
    sort($result);

    return $result;
}

/**
 * 거래 등록 화면 초기값
 */
function build_transaction_form_state(
    int $userId,
    array $defaults,
    ?array $lastState = null
): array {
    $state = [
        'transaction_date' => current_date_ymd(),
        'transaction_type' => 'expense',

        'account_id' => $defaults['default_account_id'] ?: 0,
        'related_account_id' => 0,

        'category_id' => $defaults['default_expense_category_id'] ?: 0,

        'amount' => '',
        'merchant_name' => '',
        'description' => '',

        'is_installment' => 0,
        'installment_months' => '',
        'installment_interest_rate' => '',

        'continue_after_save' => $defaults['continue_after_save'],
        'keep_last_values' => $defaults['keep_last_values'],
        'save_as_defaults' => 0,
    ];

    if (!empty($defaults['keep_last_values']) && is_array($lastState)) {
        $state = array_merge($state, $lastState);
        $state['transaction_date'] = current_date_ymd();
        $state['amount'] = '';
    }

    return $state;
}

/**
 * 유형 변경 시 기본 카테고리 자동 선택
 */
function apply_default_category_by_type(array &$state, array $defaults): void
{
    $type = $state['transaction_type'] ?? 'expense';

    if ($type === 'income') {
        $state['category_id'] = $defaults['default_income_category_id'] ?: 0;
        return;
    }

    if ($type === 'expense') {
        $state['category_id'] = $defaults['default_expense_category_id'] ?: 0;
        return;
    }

    if ($type === 'transfer') {
        $state['category_id'] = $defaults['default_transfer_category_id'] ?: 0;
        return;
    }

    if ($type === 'card_payment') {
        $state['category_id'] = $defaults['default_card_payment_category_id'] ?: 0;
        return;
    }
}

/**
 * 카드 지출이면 카드 기본계좌 우선 적용
 */
function apply_default_card_account(array &$state, array $defaults): void
{
    if (($state['transaction_type'] ?? '') !== 'expense') {
        return;
    }

    if (!empty($defaults['default_card_account_id'])) {
        $state['account_id'] = (int)$defaults['default_card_account_id'];
    }
}

/**
 * 저장 후 마지막 상태 저장
 */
function remember_transaction_form_state(array $state): void
{
    $_SESSION['tx_create_last_form'] = [
        'transaction_type' => $state['transaction_type'],
        'account_id' => $state['account_id'],
        'related_account_id' => $state['related_account_id'],
        'category_id' => $state['category_id'],

        'merchant_name' => $state['merchant_name'],
        'description' => '',

        'is_installment' => $state['is_installment'],
        'installment_months' => $state['installment_months'],
        'installment_interest_rate' => $state['installment_interest_rate'],

        'continue_after_save' => $state['continue_after_save'],
        'keep_last_values' => $state['keep_last_values'],

        'transaction_date' => current_date_ymd(),
        'amount' => '',
    ];
}

function get_remembered_transaction_form_state(): ?array
{
    return $_SESSION['tx_create_last_form'] ?? null;
}

function clear_remembered_transaction_form_state(): void
{
    unset($_SESSION['tx_create_last_form']);
}

/**
 * 기본값 자동 저장용 데이터 만들기
 */
function make_default_payload_from_form(array $state): array
{
    $payload = [
        'default_account_id' => 0,
        'default_card_account_id' => 0,

        'default_income_category_id' => 0,
        'default_expense_category_id' => 0,
        'default_transfer_category_id' => 0,
        'default_card_payment_category_id' => 0,

        'keep_last_values' => $state['keep_last_values'] ?? 1,
        'continue_after_save' => $state['continue_after_save'] ?? 1,
    ];

    $type = $state['transaction_type'] ?? 'expense';

    if ($type === 'income') {
        $payload['default_account_id'] = $state['account_id'];
        $payload['default_income_category_id'] = $state['category_id'];
    } elseif ($type === 'expense') {
        $payload['default_account_id'] = $state['account_id'];
        $payload['default_expense_category_id'] = $state['category_id'];
        $payload['default_card_account_id'] = $state['account_id'];
    } elseif ($type === 'transfer') {
        $payload['default_account_id'] = $state['account_id'];
        $payload['default_transfer_category_id'] = $state['category_id'];
    } elseif ($type === 'card_payment') {
        $payload['default_account_id'] = $state['account_id'];
        $payload['default_card_payment_category_id'] = $state['category_id'];
    }

    return $payload;
}