<?php

/*
 * Functions for the CUSF landing predictor software
 * Jon Sowman 2010
 */

require_once("config.inc.php");

// Given a POST array, create a scenario model
function createModel($post_array) {
    $pred_model = array();

    // Populate the prediction model
    $pred_model['hour'] = (int)$post_array['hour']; //adjust for GMT
    $pred_model['min'] = (int)$post_array['min'];

    // Account for no 'seconds' value, though really it should be sent
    $pred_model['sec'] = (isset($post_array['sec']) ? 
        (int)$post_array['sec'] : 0);

    $pred_model['month'] = (int)$post_array['month'];
    $pred_model['day'] = (int)$post_array['day'];
    $pred_model['year'] = (int)$post_array['year'];

    $pred_model['lat'] = $post_array['lat'];
    $pred_model['lon'] = $post_array['lon'];
    $pred_model['asc'] = (float)$post_array['ascent'];
    $pred_model['alt'] = $post_array['initial_alt'];
    $pred_model['des'] = (float)$post_array['drag'];
    $pred_model['burst'] = $post_array['burst'];

    $pred_model['delta_lat'] = $post_array['delta_lat'];
    $pred_model['delta_lon'] = $post_array['delta_lon'];

    $pred_model['wind_error'] = 0;

    $pred_model['software'] = $post_array['software'];

    // Make a timestamp of the form data
    $pred_model['timestamp'] = mktime($pred_model['hour'], $pred_model['min'], 
        $pred_model['sec'], (int)$pred_model['month'], $pred_model['day'], 
        (int)$pred_model['year'] - 2000);


    // If all was good, return the prediction model
    return $pred_model;
}

// Create a UUID by SHA1 hashing the scenario model parameters
function makesha1hash($pred_model) {
    $sha1str = "";
    foreach ( $pred_model as $idx => $value ){
        $sha1str .= $idx . "=" . $value . ",";
    }
    $uuid = sha1($sha1str);
    return $uuid;
}

// Check that the model that we built was valid
// This involves sanity checking all the parameters
function verifyModel( $pred_model, $software_available ) {
    // Check that we have not been passed an empty model
    if( !isset( $pred_model ) ) return false;

    // We will return an array of information to the calling function
    $return_array;
    $return_array['valid'] = true;

    // Iterate though the scenario parameters
    foreach( $pred_model as $idx => $value ) {
        if ( $idx == "software" ) {
            if ( !in_array( $value, $software_available ) ) {
                $return_array['valid'] = false;
                $return_array['msg'] = "The model asked for software that 
                    does not exist on this server";
            }
        } else if ( $idx == "delta_lat" || $idx == "delta_lon" ) {
            if ( $value < 1 || $value > 10 ) {
                $return_array['valid'] = false;
                $return_array['msg'] = "The latitude or longitude deltas
                    were outside the allowed range on this server";
            }
        } else if ( !is_numeric( $value ) ) {
            $return_array['valid'] = false;
            $return_array['msg'] = "A value that should have been numeric
                did not validate as such";
        }
    }

    // Now check that the timestamp is within range
    if ( $pred_model['timestamp'] > (time() + 180*3600) ) {
        // More than 180 hours into future
        $return_array['valid'] = false;
        $return_array['msg'] = "A prediction cannot be run for a time that is 
            more than 180 hours in the future";
    } else if ( $pred_model['timestamp'] < time() ) {
        // Can't run predictions in the past
        $return_array['valid'] = false;
        $return_array['msg'] = "A prediction cannot be run for a time that 
            is in the past";
    }

    // Return true if all went okay
    return $return_array;
}

// Run the prediction given a prediction model
function runPred($pred_model) {
    // Check if this is a re-run
    if ( !file_exists(PREDS_PATH . $pred_model['uuid'] . "/" . SCENARIO_FILE) ) 
    {
        // If not, make a new directory and scenario file
        makePredDir($pred_model) or die ("Couldn't create the scenario dir");
        makeINI($pred_model);
    }

    // If using GFS HD, then append --hd to the exec string
    if ( $pred_model['software'] == "gfs_hd" ) $use_hd ="--hd ";
    else $use_hd = "";

    $predictor_lat = number_format($pred_model['lat'], 0);
    $predictor_lon = number_format($pred_model['lon'], 0);

    // use `at` to automatically background the task
    $ph = popen("at now", "w");
    $sh = "./predict.py -v --latdelta="
        .$pred_model['delta_lat']." --londelta=".$pred_model['delta_lon']
        ." -p1 -f5 -t ".$pred_model['timestamp']
        ." --lat=".$predictor_lat." --lon=".$predictor_lon." " . $use_hd
        . $pred_model['uuid'];
    if (DEBUG) shell_exec("echo " . $sh . " > " . AT_LOG);
    fwrite($ph, "cd " . ROOT . " && " . $sh );
    fclose($ph);

}

// Use PHP's mkdir() to create a directory for the prediction data using
// the UUID for the scenario
function makePredDir($pred_model) {
    //make sure we use the uuid from model
    if ( mkdir( PREDS_PATH . $pred_model['uuid'] ) ) {
        return true;
    } else {
        return false;
    }
}

// Write the scenario model parameters to an INI file that can be read by
// the predictor binary
function makeINI($pred_model) { // makes an ini file
    $fh = fopen(PREDS_PATH . $pred_model['uuid'] . "/" . SCENARIO_FILE, "w"); //write

    $w_string = "[launch-site]\nlatitude = " . $pred_model['lat'] . "\naltitude = " . $pred_model['alt'] . "\n";
    $w_string .= "longitude = " . $pred_model['lon'] . "\n[atmosphere]\nwind-error = ";
    $w_string .= $pred_model['wind_error'] . "\n[altitude-model]\nascent-rate = " . $pred_model['asc'] . "\n";
    $w_string .= "descent-rate  = " . $pred_model['des'] . "\nburst-altitude = ";
    $w_string .= $pred_model['burst'] . "\n[launch-time]\nhour = " . $pred_model['hour'] . "\n";
    $w_string .= "month = " . $pred_model['month'] . "\nsecond = " . $pred_model['sec'] . "\n";
    $w_string .= "year = " . $pred_model['year'] . "\nday = " . $pred_model['day'] . "\nminute = ";
    $w_string .= $pred_model['min'] . "\n";
    // add our predictor stuff
    $w_string .= "[predictor]\nlat-delta = " . $pred_model['delta_lat'] . "\n";
    $w_string .= "lon-delta = " . $pred_model['delta_lon'] . "\nsoftware = ";
    $w_string .= $pred_model['software'] . "\n";

    fwrite($fh, $w_string);
    fclose($fh);
}

// Given a UUID, return the prediction scenario model
function getModelByUUID($uuid) {
    if ( file_exists( PREDS_PATH . $uuid . "/" . SCENARIO_FILE ) ) {
        $pred_model = parse_ini_file(PREDS_PATH . $uuid . "/" . SCENARIO_FILE);
        return $pred_model;
    } else {
        return false;
    }
}

?>