var IO = require('./io');
var meteo = require('./meteo');

// [
//     {
//         id: str
//         name: str
//         lat: str
//         lon: str

//         avg1982: {
//             d: int[365] || null,
//             w: int[52] || null,
//             m: int[12] || null,
//             y: int || null
//         },

//         avg1983: ...
//     },
//
//     {
//          id: str
//          ...
//     }
// ]


module.exports = {
    /**
     *
     */
    read: function(station, year) {
        return IO.read(meteo.dirs.json + station + '-' + year + '.json')
            .then(module.exports.parse);
    },

    /**
     *
     */
    parse: function(str) {
        var json = {};

        try {
            json = JSON.parse(str);
        } catch(e) {
            IO.error(e);
        }

        return json;
    },

    /**
     *
     */
    getStation: function() {

    },

    /**
     *
     */
    getYearlyAverage: function(arr, col) {
        var sum = 0;
        var count = 0;

        console.log('Yearly average for column ' + col + '.');

        arr.forEach(function(row) {
            sum += parseInt(row[col]);
            count++;
        });

        var avg = Math.round((sum / count) * 10) / 10 || 0;
        return avg;
    },

    /**
     *
     */
    getMonthlyAverages: function(arr, col) {
        var sum, count;
        var months = [];
        var averages = [];

        console.log('Monthly averages for column ' + col + '.');

        for (var i = 0; i < 12; i++) {
            months[i] = [];
        }

        // Assemble all the values for each month.
        arr.forEach(function(row) {
            months[row[1] - 1].push(row[col]);
        });

        // Get the average for each collection of values in each day of the year.
        months.forEach(function(values, index) {
            sum = 0;
            count = 0;

            values.map(function(val) {
                sum += parseInt(val);
                count++;
            });

            averages[index] = Math.round((sum / count) * 10) / 10 || 0;
        });

        return averages;
    },

    /**
     *
     */
    getDailyAverages: function(arr, col) {
        var sum, count, a, b, doy;
        var days = [];
        var averages = [];
        var dayms = 1000 * 60 * 60 * 24;

        console.log('Daily averages for column ' + col + '.');

        for (var i = 0; i <= 365; i++) {
            days[i] = [];
        }

        // Assemble all the values for each day of the year.
        arr.forEach(function(row) {
            a = new Date(row[0], row[1] - 1, row[2]);
            b = new Date(row[0], 0, 1);
            doy = Math.ceil((a - b) / dayms);

            days[doy].push(row[col]);
        });

        // Get the average for each collection of values in each day of the year.
        days.forEach(function(values, index) {
            sum = 0;
            count = 0;

            values.map(function(val) {
                sum += parseInt(val);
                count++;
            });

            averages[index] = Math.round((sum / count) * 10) / 10 || 0;
        });

        return averages;
    },

    /**
     *
     */
    getAverages: function(arr) {
        var columnToAverage = 14;

        // module.exports.getDailyAverages(arr, columnToAverage);
        // module.exports.getMonthlyAverages(arr, columnToAverage);
        module.exports.getYearlyAverage(arr, columnToAverage);

        return null;
    }
};