<?php

namespace Kanboard\Plugin\FinanceBuddy\Helper;

use Kanboard\Core\Base;

/**
 * Template/controller helper for FinanceBuddy.
 *
 * FinanceBuddy is opt-in per board: every render and save point is gated on isEnabled(), so an
 * un-enabled board is untouched. The enable flag lives in project metadata (financebuddy_enabled);
 * the per-task money lives in task metadata under the keys below.
 */
class FinanceHelper extends Base
{
    const ENABLED_KEY = 'financebuddy_enabled';
    const AMOUNT_KEY = 'financebuddy_amount';
    const DIRECTION_KEY = 'financebuddy_direction';
    const INSTALLMENT_CURRENT_KEY = 'financebuddy_installment_current';
    const INSTALLMENT_TOTAL_KEY = 'financebuddy_installment_total';

    // Per-board currency symbol shown before every amount (default "R$"). Up to 4 chars; the stored
    // value is trimmed, capped, and defaulted on read, so an empty or oversized value is harmless.
    const CURRENCY_KEY = 'financebuddy_currency';
    const CURRENCY_DEFAULT = 'R$';
    const CURRENCY_MAX_LENGTH = 4;

    // Per-column opt-out of the header total. Stored per column in PROJECT metadata as
    // financebuddy_hide_total_<column_id> = 'on' (hidden) or 'off' (shown, the default). Literal
    // on/off, never 1/0, so the flag is never dropped by the metadata save (PHP empty("0") === true).
    const HIDE_TOTAL_PREFIX = 'financebuddy_hide_total_';
    const HIDE_TOTAL_ON = 'on';
    const HIDE_TOTAL_OFF = 'off';

    // Hidden marker present only when the task form was submitted with the finance fieldset, so
    // non-finance task updates (moves, API calls) are ignored by the persistence hooks.
    const FORM_MARKER = 'financebuddy_form';

    // Memoized per project_id: the board hooks below call isEnabled() once per card.
    private static $enabledCache = array();

    // Memoized per project_id: currency() is likewise resolved once per card/column render.
    private static $currencyCache = array();

    /**
     * Is FinanceBuddy enabled for this board?
     *
     * @param  integer $project_id
     * @return bool
     */
    public function isEnabled($project_id)
    {
        $project_id = (int) $project_id;

        if (! isset(self::$enabledCache[$project_id])) {
            self::$enabledCache[$project_id] = (int) $this->projectMetadataModel->get($project_id, self::ENABLED_KEY, 0) === 1;
        }

        return self::$enabledCache[$project_id];
    }

    /**
     * Per-board currency symbol shown before amounts: the stored value trimmed and capped to
     * CURRENCY_MAX_LENGTH, or CURRENCY_DEFAULT ("R$") when empty. Memoized per project.
     *
     * @param  integer $project_id
     * @return string
     */
    public function currency($project_id)
    {
        $project_id = (int) $project_id;

        if (! isset(self::$currencyCache[$project_id])) {
            $symbol = trim((string) $this->projectMetadataModel->get($project_id, self::CURRENCY_KEY, ''));
            $symbol = mb_substr($symbol, 0, self::CURRENCY_MAX_LENGTH);
            self::$currencyCache[$project_id] = $symbol === '' ? self::CURRENCY_DEFAULT : $symbol;
        }

        return self::$currencyCache[$project_id];
    }

    /**
     * Stored finance values for a task, with defaults. One query (getAll) since the board renders
     * this per card.
     *
     * @param  integer $task_id
     * @return array
     */
    public function get($task_id)
    {
        $all = $this->taskMetadataModel->getAll($task_id);

        return array(
            'amount' => isset($all[self::AMOUNT_KEY]) ? $all[self::AMOUNT_KEY] : '',
            'direction' => (isset($all[self::DIRECTION_KEY]) && $all[self::DIRECTION_KEY] === 'credit') ? 'credit' : 'debit',
            'installment_current' => isset($all[self::INSTALLMENT_CURRENT_KEY]) ? $all[self::INSTALLMENT_CURRENT_KEY] : '',
            'installment_total' => isset($all[self::INSTALLMENT_TOTAL_KEY]) ? $all[self::INSTALLMENT_TOTAL_KEY] : '',
        );
    }

    /**
     * Net money for a board column: credits positive, debits negative, summed over the cards in
     * the column. One grouped query over the column's task ids (the task rows carry no metadata).
     *
     * @param  array $column  A board column as passed to template:board:column:header ('tasks').
     * @return float
     */
    public function columnNet(array $column)
    {
        if (empty($column['tasks'])) {
            return 0.0;
        }

        $task_ids = array();
        foreach ($column['tasks'] as $task) {
            $task_ids[] = (int) $task['id'];
        }

        $rows = $this->db->table('task_has_metadata')
            ->columns('task_id', 'name', 'value')
            ->in('task_id', $task_ids)
            ->in('name', array(self::AMOUNT_KEY, self::DIRECTION_KEY))
            ->findAll();

        $amounts = array();
        $directions = array();

        foreach ($rows as $row) {
            if ($row['name'] === self::AMOUNT_KEY) {
                $amounts[$row['task_id']] = (float) $row['value'];
            } else {
                $directions[$row['task_id']] = $row['value'];
            }
        }

        $net = 0.0;
        foreach ($amounts as $task_id => $amount) {
            if ($amount <= 0) {
                continue;
            }

            $is_credit = isset($directions[$task_id]) && $directions[$task_id] === 'credit';
            $net += $is_credit ? $amount : -$amount;
        }

        return $net;
    }

    /**
     * Has this column's header total been hidden (per-column opt-out)?
     *
     * @param  integer $project_id
     * @param  integer $column_id
     * @return bool
     */
    public function isTotalHidden($project_id, $column_id)
    {
        return $this->projectMetadataModel->get((int) $project_id, self::HIDE_TOTAL_PREFIX.(int) $column_id, self::HIDE_TOTAL_OFF) === self::HIDE_TOTAL_ON;
    }

    /**
     * Values to prefill the task-form fields: a re-post (after a validation error) wins, then the
     * stored metadata for an existing task, otherwise blanks for a new task.
     *
     * @param  array $values
     * @return array
     */
    public function formValues(array $values)
    {
        if (isset($values[self::FORM_MARKER])) {
            return array(
                'amount' => isset($values[self::AMOUNT_KEY]) ? $values[self::AMOUNT_KEY] : '',
                'direction' => (isset($values[self::DIRECTION_KEY]) && $values[self::DIRECTION_KEY] === 'credit') ? 'credit' : 'debit',
                'installment_current' => isset($values[self::INSTALLMENT_CURRENT_KEY]) ? $values[self::INSTALLMENT_CURRENT_KEY] : '',
                'installment_total' => isset($values[self::INSTALLMENT_TOTAL_KEY]) ? $values[self::INSTALLMENT_TOTAL_KEY] : '',
            );
        }

        if (! empty($values['id'])) {
            return $this->get($values['id']);
        }

        return array('amount' => '', 'direction' => 'debit', 'installment_current' => '', 'installment_total' => '');
    }

    /**
     * Parse a user-typed amount. Accepts a dot or a comma as the decimal separator and an optional
     * "R$"; there is no thousand separator. Returns a non-negative float (0.0 when unparseable).
     *
     * @param  string $raw
     * @return float
     */
    public static function parseAmount($raw)
    {
        $raw = str_replace(array('R$', ' '), '', trim((string) $raw));
        $raw = str_replace(',', '.', $raw);

        if ($raw === '' || ! is_numeric($raw)) {
            return 0.0;
        }

        $value = round((float) $raw, 2);

        return $value > 0 ? $value : 0.0;
    }

    /**
     * Format a money value for display: two decimals, comma decimal separator, no thousand
     * separator (e.g. 20.9 -> "20,90"). Accepts a float or a canonical dot-string.
     *
     * @param  float|string $amount
     * @return string
     */
    public static function money($amount)
    {
        return number_format((float) $amount, 2, ',', '');
    }
}