//
// tempdb.js - SQLite Backend for storing and retrieving temperatures
//

var sqlite3 = require("sqlite3").verbose();
var file = "./temperatures.db"

exports.getAll = function(req, res) {
	var db = new sqlite3.Database(file);
	var data = []

	db.serialize(function() {		
		db.all("SELECT id, name, lasttemp as temp, lastupd as ts FROM sensors ORDER BY id;", function(err, rows) {
			if (rows.length > 0) {
				getTempRecursive(rows, data, res);
				db.close();				
			} else {
				db.close();
				res.status(400).send({"errid": 4, "errtxt": "No Sensors in Database"});
				return;
			}
		});
	});
}

exports.getTemp = function(req, res) {

	if (req.query.from === undefined || req.query.to === undefined) {
	
		var db = new sqlite3.Database(file);
		var data = [];
	
		db.serialize(function() {		
			db.get("SELECT id, name, lasttemp as temp, lastupd as ts FROM sensors WHERE id = ?;", req.params.id, function(err, row) {
				if (row !== undefined) {
					data = row;
					db.get("SELECT avg(value) as avg, max(value) as max, timestamp from temp_" + data.id + ";", function(err, row) {
						if (row !== undefined) {
						  data.avg = row.avg;
							data.max = row.max;
							data.tsmax = row.timestamp;
							db.get("SELECT min(value) as min, timestamp from temp_" + data.id + ";", function(err, row) {
								if (row !== undefined) {
									data.min = row.min;
									data.tsmin = row.timestamp;
									db.close();
									res.type("application/json");
									res.status(200).send(data);
								}
							});
						}
					});
				} else {
					db.close();
					res.status(400).send({"errid": 3, "errtxt": "Sensor does not exist"});
				}
			});
		});
	} else {	
		var db = new sqlite3.Database(file);
		var data = [];

		db.serialize(function() {
			db.each("select timestamp as ts, value as temp from temp_" + req.params.id + " where timestamp >= ? and timestamp <= ?;", req.query.from, req.query.to,
				function(err, row) {
					data.push([row.ts, row.temp]);
				},
				function(err, num) {
					res.status(200).send(data);
				}
			);
		});
	}
}

exports.addTemp = function(req, res) {
	var db = new sqlite3.Database(file);
	db.serialize(function() {
		db.run("CREATE TABLE IF NOT EXISTS sensors (id INTEGER PRIMARY KEY ASC, name TEXT, lasttemp NUMERIC, lastupd INTEGER);");	

		var name = req.body.name;

		if (name == "") {
			res.status(400).send({"errid": 1, "errtxt": "Missing parameters"});
			return;
		}

		
		db.get("SELECT id, name FROM sensors WHERE name = ?", name, function(err, row) {
			if (row === undefined) {
				db.run("INSERT INTO sensors VALUES (NULL, ?, NULL, NULL);", name);
				db.get("SELECT id, name FROM sensors WHERE name = ?", name, function(err, row) {
					if (row !== undefined) {
						db.run("CREATE TABLE IF NOT EXISTS temp_" + row.id + " (timestamp TIMESTAMP, value NUMERIC);");
						db.close();
						res.status(200).send(row);
					} else {
						res.status(400).send({"errid": 4, "errtxt": "Error inserting sensor"});
						db.close();
					}
				});
			} else {
				res.status(400).send({"errid": 2, "errtxt": "Sensor already exists"});
				db.close();
			}
		});
	});
}

exports.updTemp = function(req, res) {
	if (req.body.temp === undefined) {
		res.status(400).send({"errid": 1, "errtxt": "Missing parameters"});
		return;
	}
	
	if (req.body.ts === undefined) {
	  var d = new Date();
		var ts = d.getTime();
	} else {
		var ts = req.body.ts;
	}
	
	var db = new sqlite3.Database(file);
	db.serialize(function() {
		db.get("SELECT id, name FROM sensors WHERE id = ?", req.params.id, function(err, row) {
			if (row !== undefined) {
				db.run("INSERT INTO temp_" + req.params.id + " VALUES (?, ?)", ts, req.body.temp);
				db.run("UPDATE sensors SET lasttemp = ?, lastupd = ? where id = ?;", req.body.temp, ts, req.params.id);
				db.close();
				res.status(200).end();
			} else {
				db.close();
				res.status(400).send({"errid": 3, "errtxt": "Sensor does not exist"});
			}
		});
	});
}

// Helper Functions

function getTempRecursive(rows, data, res) {

	if (rows.length > 0) {

		var cur = rows.shift();
		var db = new sqlite3.Database(file);
		db.get("SELECT avg(value) as avg, max(value) as max, timestamp from temp_" + cur.id + ";", function(err, row) {
			if (row !== undefined) {
			  cur.avg = row.avg;
				cur.max = row.max;
				cur.tsmax = row.timestamp;
				db.get("SELECT min(value) as min, timestamp from temp_" + cur.id + ";", function(err, row) {
					if (row !== undefined) {
						cur.min = row.min;
						cur.tsmin = row.timestamp;
						db.close();
						data.push(cur);
						getTempRecursive(rows, data, res);
					}
				});
			}
		});
	} else {
		res.status(200).send(data);
	}
}