<?php

header("content-type: application/javascript");

require_once 'config.php';

/*

Not used, but might be handy later.
-----------------------------------

function total_responses(){
    $stmt = $mysqli->prepare("select COUNT(*) from responces");
    $stmt->execute();
    $stmt->bint_result($num_rows);
    $stmt->fetch();
    return $num_rows;
}

function responces_for_age($age){
    $stmt = $mysqli->prepare("select COUNT(responces.id) from responces join images on images.id=responces.image_id where age=?");
    $stmt->bind_param("i", $age);
    $stmt->execute();
    $stmt->bind_result($num_rows);
    $stmt->fetch();
    return $num_rows;
}

function average_score(){
    $stmt = $mysqli->prepare("select AVG(score) from responces");
    $stmt->execute();
    $stmt->bind_result($avg_score);
    $stmt->fetch();
    return $avg_score;
}

function average_score_in_time_period($time_start, $time_end){
    $stmt = $mysqli->prepare("select AVG(score) from responces where datetime >= ? or datetime <= ?");
    $stmt->bind_param("ii", $time_start, $time_end);
    $stmt->execute();
    $stmt->bind_param($avg_score);
    return $avg_score;
}

function average_score_for_age_in_time_period($age, $time_start, $time_end){
    $stmt = $mysqli->prepare("select AVG(score) from responces join images on images.id=responces.image_id where age=? and (datetime >= ? or datetime <= ?)");
    $stmt->bind_param("ii", $time_start, $time_end);
    $stmt->execute();
    $stmt->bind_param($avg_score);
    return $avg_score;
}

*/

function average_score_for_age($age){
    $stmt = $mysqli->prepare("select AVG(score) from responces join images on images.id=responces.image_id where age=?");
    $stmt->bind_param("i", $age);
    $stmt->execute();
    $stmt->bind_result($avg_score);
    $stmt->fetch();
    return $avg_score;
}

function heighest_scoring_age_in_time_period($time_start, $time_end){
    $stmt = $mysqli->prepare("select age from images join responce on images.id=responce.image_id where datetime >= ? or datetime <= ? order by AVG(responce.score) desc limit 1");
    $stmt->bind_param("ii", $time_start, $time_end);
    $stmt->execute();
    $stmt->bind_param($age);
    return $age;
}

function score_against_avg_age(){
    $graph = array();
    for ($a = MIN_AGE; $a <= MAX_AGE; $a++){
        array_push($graph, array(
            "age" => $a,
            "score" => average_score_for_age($a)//should rewrite as stored function, as this is a lot of mysql transactions; slow!
            ));
    }
    return $graph;
}

function highest_scoring_age_againts_time(){
    //find oldest responce
    $stmt = $mysqli->prepare("select UNIX_TIMESTAMP(datetime) from images order by datetime asc limit 1");
    $stmt->execute();
    $stmt->bind_result($start_datetime);
    $stmt->fetch();
    //create time periods
    $age_diff = MAX_AGE - MIN_AGE;
    $now = time();
    $total_time_elapsed = $now - $start_datetime;
    $time_period = intval($total_time_elapsed / $age_diff);
    $graph = array();
    while ($age_diff != 0) {
        $end_time = $start_datetime + $time_period;
        array_push($graph, array(
            "startTime" => $start_datetime,
            "endTime" => $end_time,
            "age" => heighest_scoring_age_in_time_period($start_datetime, $end_time)// this could also do with being an sql function.
            ));
        $start_datetime = $end_time;
        $age_diff--;
    }
    return $graph;
}

function output_graph($graph){
    echo json_encode($graph);
}


//inspect request and serve graph data
if($_POST['graph']){
    switch ($_POST['graph']) {
        case 'scoreAgainstAvgAge':
            output_graph(scoreAgainstAvgAge());
            break;

        case 'highestScoringAgeAgaintsTime':
            output_graph(highest_scoring_age_againts_time());
            break;
    }
}