// Copyright 2015 Brian J. Downs
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package openweathermap

import (
	"errors"
	"net/http"
)

var errUnitUnavailable = errors.New("unit unavailable")
var errLangUnavailable = errors.New("language unavailable")
var errInvalidKey = errors.New("invalid api key")
var errInvalidOption = errors.New("invalid option")
var errInvalidHttpClient = errors.New("invalid http client")
var errForecastUnavailable = errors.New("forecast unavailable")

// DataUnits represents the character chosen to represent the temperature notation
var DataUnits = map[string]string{"C": "metric", "F": "imperial", "K": "internal"}
var (
	baseURL        = "http://api.openweathermap.org/data/2.5/weather?%s"
	iconURL        = "http://openweathermap.org/img/w/%s"
	stationURL     = "http://api.openweathermap.org/data/2.5/station?id=%d"
	forecast5Base  = "http://api.openweathermap.org/data/2.5/forecast?appid=%s&%s&mode=json&units=%s&lang=%s&cnt=%d"
	forecast16Base = "http://api.openweathermap.org/data/2.5/forecast/daily?appid=%s&%s&mode=json&units=%s&lang=%s&cnt=%d"
	historyURL     = "http://api.openweathermap.org/data/2.5/history/%s"
	pollutionURL   = "http://api.openweathermap.org/pollution/v1/co/"
	uvURL          = "http://api.openweathermap.org/data/2.5/"
	dataPostURL    = "http://openweathermap.org/data/post"
)

// LangCodes holds all supported languages to be used
// inspried and sourced from @bambocher (github.com/bambocher)
var LangCodes = map[string]string{
	"EN":    "English",
	"RU":    "Russian",
	"IT":    "Italian",
	"ES":    "Spanish",
	"SP":    "Spanish",
	"UK":    "Ukrainian",
	"UA":    "Ukrainian",
	"DE":    "German",
	"PT":    "Portuguese",
	"RO":    "Romanian",
	"PL":    "Polish",
	"FI":    "Finnish",
	"NL":    "Dutch",
	"FR":    "French",
	"BG":    "Bulgarian",
	"SV":    "Swedish",
	"SE":    "Swedish",
	"TR":    "Turkish",
	"HR":    "Croatian",
	"CA":    "Catalan",
	"ZH_TW": "Chinese Traditional",
	"ZH":    "Chinese Simplified",
	"ZH_CN": "Chinese Simplified",
}

// Config will hold default settings to be passed into the
// "NewCurrent, NewForecast, etc}" functions.
type Config struct {
	Mode     string // user choice of JSON or XML
	Unit     string // measurement for results to be displayed.  F, C, or K
	Lang     string // should reference a key in the LangCodes map
	APIKey   string // API Key for connecting to the OWM
	Username string // Username for posting data
	Password string // Pasword for posting data
}

// APIError returned on failed API calls.
type APIError struct {
	Message string `json:"message"`
	COD     string `json:"cod"`
}

// Coordinates struct holds longitude and latitude data in returned
// JSON or as parameter data for requests using longitude and latitude.
type Coordinates struct {
	Longitude float64 `json:"lon"`
	Latitude  float64 `json:"lat"`
}

// Sys struct contains general information about the request
// and the surrounding area for where the request was made.
type Sys struct {
	Type    int     `json:"type"`
	ID      int     `json:"id"`
	Message float64 `json:"message"`
	Country string  `json:"country"`
	Sunrise int     `json:"sunrise"`
	Sunset  int     `json:"sunset"`
}

// Wind struct contains the speed and degree of the wind.
type Wind struct {
	Speed float64 `json:"speed"`
	Deg   float64 `json:"deg"`
}

// Weather struct holds high-level, basic info on the returned
// data.
type Weather struct {
	ID          int    `json:"id"`
	Main        string `json:"main"`
	Description string `json:"description"`
	Icon        string `json:"icon"`
}

// Main struct contains the temperates, humidity, pressure for the request.
type Main struct {
	Temp      float64 `json:"temp"`
	TempMin   float64 `json:"temp_min"`
	TempMax   float64 `json:"temp_max"`
	Pressure  float64 `json:"pressure"`
	SeaLevel  float64 `json:"sea_level"`
	GrndLevel float64 `json:"grnd_level"`
	Humidity  int     `json:"humidity"`
}

// Clouds struct holds data regarding cloud cover.
type Clouds struct {
	All int `json:"all"`
}

// 	return key
// }
func setKey(key string) (string, error) {
	if err := ValidAPIKey(key); err != nil {
		return "", err
	}
	return key, nil
}

// ValidDataUnit makes sure the string passed in is an accepted
// unit of measure to be used for the return data.
func ValidDataUnit(u string) bool {
	for d := range DataUnits {
		if u == d {
			return true
		}
	}
	return false
}

// ValidLangCode makes sure the string passed in is an
// acceptable lang code.
func ValidLangCode(c string) bool {
	for d := range LangCodes {
		if c == d {
			return true
		}
	}
	return false
}

// ValidDataUnitSymbol makes sure the string passed in is an
// acceptable data unit symbol.
func ValidDataUnitSymbol(u string) bool {
	for _, d := range DataUnits {
		if u == d {
			return true
		}
	}
	return false
}

// ValidAPIKey makes sure that the key given is a valid one
func ValidAPIKey(key string) error {
	if len(key) == 32 {
		return errors.New("invalid key")
	}
	return nil
}

// CheckAPIKeyExists will see if an API key has been set.
func (c *Config) CheckAPIKeyExists() bool { return len(c.APIKey) > 1 }

// Settings holds the client settings
type Settings struct {
	client *http.Client
}

// NewSettings returns a new Setting pointer with default http client.
func NewSettings() *Settings {
	return &Settings{
		client: http.DefaultClient,
	}
}

// Optional client settings
type Option func(s *Settings) error

// WithHttpClient sets custom http client when creating a new Client.
func WithHttpClient(c *http.Client) Option {
	return func(s *Settings) error {
		if c == nil {
			return errInvalidHttpClient
		}
		s.client = c
		return nil
	}
}

// setOptions sets Optional client settings to the Settings pointer
func setOptions(settings *Settings, options []Option) error {
	for _, option := range options {
		if option == nil {
			return errInvalidOption
		}
		err := option(settings)
		if err != nil {
			return err
		}
	}
	return nil
}