<?php
/**
 * Provides the assignment class, an interface to the assignment table in the database
 * 
 * @author Camil Staps
 * 
 * BusinessAdmin: administrative software for small companies
 * Copyright (C) 2015 Camil Staps (ViviSoft)
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * An interface to the assignment table in the database
 */
class assignment {
    /**
     * @var pdo $pdo                The PDO class for database communication
     * @var int $id                 The id of the assignment
     * @var int $offerId            The id of the offer this assignment is linked to
     * @var string $title           The title of the assignment
     * @var string $description     The description of the assignment
     * @var int $hours              The amount of hours of the assignment
     * @var float $price_per_hour   The price per hour for this assignment, in your valuta
     * @var float $vat              The percentage of VAT to calculate on this assignment
     */
    protected $pdo, $offerId, $id, $title, $description, $hours, $price_per_hour, $vat;

    const SUBTOTAL = 1;
    const VAT = 2;
    const TOTAL = 3;

    /**
     * Create a new instance
     * 
     * @param PDO $pdo              The PDO class, to access the database
     * @param int $id               The id of the assignment to fetch
     * 
     * @throws PDOException         If something went wrong with the database
     * @throws Exception            If the assignment could not be found
     */
    public function __construct($pdo, $id) {
        $this->pdo = $pdo;

        $stmt = $this->pdo->prepare("SELECT * FROM `".constants::db_prefix."assignment` WHERE `id`=?");
        $stmt->execute(array($id));
        if ($stmt->rowCount() == 0) {
            throw new Exception("The assignment with id '$id' could not be found.");
        }
        $assignment = $stmt->fetch(PDO::FETCH_ASSOC);

        $this->id = $assignment['id'];
        $this->offerId = $assignment['offerId'];
        $this->title = $assignment['title'];
        $this->description = $assignment['description'];
        $this->hours = $assignment['hours'];
        $this->price_per_hour = $assignment['price_per_hour'];
        $this->vat = $assignment['VAT_percentage'];
    }

    //------------------------------------------------------------------------------
    // Getters and setters
    //------------------------------------------------------------------------------

    /**
     * Get the ID of the assignment
     * 
     * @return int                  The ID
     */
    public function getId() {
        return $this->id;
    }

    /**
     * Get the ID of the offer that this assignment is linked to
     * 
     * @return int                  The ID
     */
    public function getOfferId() {
        return $this->offerId;
    }

    /**
     * Get the offer that this assignment is linked to
     * 
     * @return offer                The offer
     */
    public function getOffer() {
        return new offer($this->pdo, $this->offerId);
    }

    /**
     * Get the title of the assignment
     * 
     * @return string               The title
     */
    public function getTitle() {
        return $this->title;
    }

    /**
     * Set the title of the assignment
     * 
     * @param string $title          The new title for the assignment
     * 
     * @throws PDOException          If something went wrong with the database
     * 
     * @return bool                  True on succes, false on failure
     */
    public function setTitle($title) {
        $stmt = $this->pdo->prepare("UPDATE `".constants::db_prefix."assignment` SET `title`=? WHERE `id`=?");
        $stmt->execute(array($title, $this->id));
        if ($stmt->rowCount() == 1) {
            $this->title = $title;
            return true;
        } else {
            return false;
        }
    }

    /**
     * Get the description of the assignment
     * 
     * @param bool $parseMarkdown    Whether or not to parse markdown
     * 
     * @return string                The description
     */
    public function getDescription($parseMarkdown = true) {
        if ($parseMarkdown) {
            $pd = new Parsedown;
            return $pd->text($this->description);
        } else {
            return $this->description;
        }
    }

    /**
     * Set the description of the assignment
     * 
     * @param string $description    The new description for the assignment
     * 
     * @throws PDOException          If something went wrong with the database
     * 
     * @return bool                  True on succes, false on failure
     */
    public function setDescription($description) {
        $stmt = $this->pdo->prepare("UPDATE `".constants::db_prefix."assignment` SET `description`=? WHERE `id`=?");
        $stmt->execute(array($description, $this->id));
        if ($stmt->rowCount() == 1) {
            $this->description = $description;
            return true;
        } else {
            return false;
        }
    }

    /**
     * Get the amount of hours of the assignment
     * 
     * @return int                   The amount of hours
     */
    public function getHours() {
        return $this->hours;
    }

    /**
     * Set the amount of hours of the assignment
     * 
     * @param int $hours             The new amount hours for the assignment
     * 
     * @throws PDOException          If something went wrong with the database
     * 
     * @return bool                  True on succes, false on failure
     */
    public function setHours($hours) {
        $stmt = $this->pdo->prepare("UPDATE `".constants::db_prefix."assignment` SET `hours`=? WHERE `id`=?");
        $stmt->execute(array($hours, $this->id));
        if ($stmt->rowCount() == 1) {
            $this->hours = $hours;
            return true;
        } else {
            return false;
        }
    }

    /**
     * Get the price per hour of the assignment
     * 
     * @return float                 The price per hour
     */
    public function getPricePerHour() {
        return $this->price_per_hour;
    }

    /**
     * Set the price per hour of the assignment
     * 
     * @param float $price_per_hour  The new price per hour for the assignment
     * 
     * @throws PDOException          If something went wrong with the database
     * 
     * @return bool                  True on succes, false on failure
     */
    public function setPricePerHour($price_per_hour) {
        $stmt = $this->pdo->prepare("UPDATE `".constants::db_prefix."assignment` SET `price_per_hour`=? WHERE `id`=?");
        $stmt->execute(array($price_per_hour, $this->id));
        if ($stmt->rowCount() == 1) {
            $this->price_per_hour = $price_per_hour;
            return true;
        } else {
            return false;
        }
    }

    /**
     * Get the VAT percentage of the assignment
     * 
     * @return float                 The VAT percentage
     */
    public function getVAT() {
        return $this->vat;
    }

    /**
     * Set the VAT percentage of the assignment
     * 
     * @param float $vat             The new VAT percentage for the assignment
     * 
     * @throws PDOException          If something went wrong with the database
     * 
     * @return bool                  True on succes, false on failure
     */
    public function setVAT($vat) {
        $stmt = $this->pdo->prepare("UPDATE `".constants::db_prefix."assignment` SET `VAT_percentage`=? WHERE `id`=?");
        $stmt->execute(array($vat, $this->id));
        if ($stmt->rowCount() == 1) {
            $this->vat = $vat;
            return true;
        } else {
            return false;
        }
    }

    //------------------------------------------------------------------------------
    // Other functions
    //------------------------------------------------------------------------------

    /**
     * Calculate useful numbers about the assignment
     * 
     * Subtotal: price_per_hour \* hours
     * 
     * VAT: subtotal \* VAT_percentage
     * 
     * Total: subtotal + VAT
     * 
     * @param int $what              Any of assignment::SUBTOTAL, assignment::VAT, assignment::TOTAL
     * @param int $round             How many decimals to round on
     * @param bool $format           Whether to format the number nicely (for output) or not (for calculations)
     * 
     * @throws PDOException          If something went wrong with the database
     * 
     * @return float|bool            The calculated value rounded on $round decimals, or false when the input is incorrect
     */
    public function calculate($what = self::TOTAL, $round = 2, $format = true) {
        $return = 0;
        switch ($what) {
            case self::SUBTOTAL:
                $return = $this->getPricePerHour() * $this->getHours();
                break;
            case self::VAT:
                $return = $this->calculate(self::SUBTOTAL, $round + 1, false) * $this->getVAT() / 100;
                break;
            case self::TOTAL:
                $return = $this->calculate(self::SUBTOTAL, $round + 1, false) + $this->calculate(self::VAT, $round + 1, false);
                break;
            default:
                return false;
        }
        if ($format) {
            return number_format($return, $round);
        } else {
            return round($return, $round);
        }
    }

    /**
     * Remove this assignment from the database
     * 
     * If this doesn't succeed (i.e. false is returned), that means the assignment was removed manually or by another instance of this class
     * 
     * @throws PDOException          If something went wrong with the database
     * 
     * @return bool                  True on success, false on failure
     */
    public function delete() {
        $stmt = $this->pdo->prepare("DELETE FROM `".constants::db_prefix."assignment` WHERE `id`=?");
        $stmt->execute(array($this->id));
        if ($stmt->rowCount() != 1) {
            return false;
        } else {
            return true;
        }
    }
}