httpd = require 'httpd'
math = require 'math'
sqlite = require 'sqlite'

cities = {"London", "Manchester", "Birmingham", "Leeds", "Glasgow", "Southampton", "Liverpool", "Newcastle", "Nottingham", "Sheffield", "Bristol", "Belfast", "Leicester"}

weather_desc = {"sunny", "cloudy", "partially cloudy", "rainy", "snowy"}


function valid_city(cities, city)
    for i, v in ipairs(cities) do
        if v == city
        then
            return true
        end
    end
    return false
end


function forecast(env, headers, query)
    if query and query["city"]
    then
        local city = query["city"]
        if city == "list"
        then 
            httpd.write("HTTP/1.1 200 Ok\r\n")
            httpd.write("Content-Type: application/json\r\n\r\n")
            httpd.write('{"code": 200,')
            httpd.write('"cities": [')
            for k,v in pairs(cities) do
                httpd.write('"' .. v .. '"')
                if k < #cities
                then
                    httpd.write(',')
                end
            end
            httpd.write(']}')
        elseif not valid_city(cities, city)
        then
            httpd.write("HTTP/1.1 500 Error\r\n")
            httpd.write("Content-Type: application/json\r\n\r\n")
            httpd.write('{"code": 500,')
            httpd.write('"error": "unknown city: ' .. city .. '"}')
        else
            -- just some fake weather data
            weather_data = {
                {
                    ["date"] = os.date("%Y-%m-%d", os.time()),
                    ["desc"] = weather_desc[math.random(#weather_desc)],
                    ["tempmin"] = math.random(30),
                    ["tempmax"] = math.random(30,50),
                    ["pressure"] = math.random(1000,2000),
                    ["humidity"] = math.random(0,100),
                    ["windspeed"] = math.random() + math.random(4),
                    ["winddegree"] = math.random() + math.random(364),
                },
                {
                    ["date"] = os.date("%Y-%m-%d", os.time()+86400),
                    ["desc"] = weather_desc[math.random(#weather_desc)],
                    ["tempmin"] = math.random(30),
                    ["tempmax"] = math.random(30,50),
                    ["pressure"] = math.random(1000,2000),
                    ["humidity"] = math.random(0,100),
                    ["windspeed"] = math.random() + math.random(4),
                    ["winddegree"] = math.random() + math.random(364),
                },
                {
                    ["date"] = os.date("%Y-%m-%d", os.time()+86400*2),
                    ["desc"] = weather_desc[math.random(#weather_desc)],
                    ["tempmin"] = math.random(30),
                    ["tempmax"] = math.random(30,50),
                    ["pressure"] = math.random(1000,2000),
                    ["humidity"] = math.random(0,100),
                    ["windspeed"] = math.random() + math.random(4),
                    ["winddegree"] = math.random() + math.random(364),
                },
                {
                    ["date"] = os.date("%Y-%m-%d", os.time()+86400*3),
                    ["desc"] = weather_desc[math.random(#weather_desc)],
                    ["tempmin"] = math.random(30),
                    ["tempmax"] = math.random(30,50),
                    ["pressure"] = math.random(1000,2000),
                    ["humidity"] = math.random(0,100),
                    ["windspeed"] = math.random() + math.random(4),
                    ["winddegree"] = math.random() + math.random(364),
                },
                {
                    ["date"] = os.date("%Y-%m-%d", os.time()+86400*4),
                    ["desc"] = weather_desc[math.random(#weather_desc)],
                    ["tempmin"] = math.random(30),
                    ["tempmax"] = math.random(30,50),
                    ["pressure"] = math.random(1000,2000),
                    ["humidity"] = math.random(0,100),
                    ["windspeed"] = math.random() + math.random(4),
                    ["winddegree"] = math.random() + math.random(364),
                },
            }

            httpd.write("HTTP/1.1 200 Ok\r\n")
            httpd.write("Content-Type: application/json\r\n\r\n")
            httpd.write('{"code": 200,')
            httpd.write('"city": "' .. city .. '",')
            httpd.write('"list": [')

            for i = 1, #weather_data - 1
            do
                httpd.write('{"date": "' .. weather_data[i]["date"] .. '",')
                httpd.write('"weather": {')
                httpd.write('"description": "' .. weather_data[i]["desc"] .. '",')
                httpd.write('"temperature": {')
                httpd.write('"min": "' .. weather_data[i]["tempmin"] ..'",')
                httpd.write('"max": "' .. weather_data[i]["tempmax"] .. '"},')
                httpd.write('"pressure": "' .. weather_data[i]["pressure"] .. '",')
                httpd.write('"humidity": "' .. weather_data[i]["humidity"] .. '",')
                httpd.write('"wind": {')
                httpd.write('"speed": "' .. weather_data[i]["windspeed"] .. '",')
                httpd.write('"degree": "' .. weather_data[i]["winddegree"] .. '"}}},')
            end

            httpd.write('{"date": "' .. weather_data[#weather_data]["date"] .. '",')
            httpd.write('"weather": {') 
            httpd.write('"description": "' .. weather_data[#weather_data]["desc"] .. '",')
            httpd.write('"temperature": {') 
            httpd.write('"min": "' .. weather_data[#weather_data]["tempmin"] ..'",')
            httpd.write('"max": "' .. weather_data[#weather_data]["tempmax"] .. '"},')
            httpd.write('"pressure": "' .. weather_data[#weather_data]["pressure"] .. '",')
            httpd.write('"humidity": "' .. weather_data[#weather_data]["humidity"] .. '",')
            httpd.write('"wind": {') 
            httpd.write('"speed": "' .. weather_data[#weather_data]["windspeed"] .. '",')
            httpd.write('"degree": "' .. weather_data[#weather_data]["winddegree"] .. '"}}}]}')
        end 
    else
        httpd.write("HTTP/1.1 500 Error\r\n")
        httpd.write("Content-Type: application/json\r\n\r\n")
        httpd.print('{"code": 500, "error": "No city specified. Use \'city=list\' to list available cities."}')
    end
end

httpd.register_handler('forecast', forecast)