// Package gomdb is a golang implementation of the OMDB API.
package gomdb

import (
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"net/url"
)

const (
	baseURL  = "https://www.omdbapi.com"
	plot     = "full"
	tomatoes = "true"

	MovieSearch   = "movie"
	SeriesSearch  = "series"
	EpisodeSearch = "episode"
)

type OmdbApi struct {
	apiKey string
}

func Init(apiKey string) *OmdbApi {
	return &OmdbApi{apiKey: apiKey}
}

// QueryData is the type to create the search query
type QueryData struct {
	Title      string
	Year       string
	ImdbId     string
	SearchType string
	Season     string
	Episode    string
}

// SearchResult is the type for the search results
type SearchResult struct {
	Title  string
	Year   string
	ImdbID string
	Type   string
}

// SearchResponse is the struct of the response in a search
type SearchResponse struct {
	Search       []SearchResult
	Response     string
	Error        string
	totalResults int
}

// Ratings is a combination of all ratings
type Ratings struct {
	Source string
	Value  string
}

// MovieResult is the result struct of an specific movie search
type MovieResult struct {
	Title      string    `json:"Title"`
	Year       string    `json:"Year"`
	Rated      string    `json:"Rated"`
	Released   string    `json:"Released"`
	Runtime    string    `json:"Runtime"`
	Genre      string    `json:"Genre"`
	Director   string    `json:"Director"`
	Writer     string    `json:"Writer"`
	Actors     string    `json:"Actors"`
	Plot       string    `json:"Plot"`
	Language   string    `json:"Language"`
	Country    string    `json:"Country"`
	Awards     string    `json:"Awards"`
	Poster     string    `json:"Poster"`
	Ratings    []Ratings `json:"Ratings"`
	Metascore  string    `json:"Metascore"`
	ImdbRating string    `json:"imdbRating"`
	ImdbVotes  string    `json:"imdbVotes"`
	ImdbID     string    `json:"imdbID"`
	Type       string    `json:"Type"`
	DVD        string    `json:"DVD"`
	BoxOffice  string    `json:"BoxOffice"`
	Production string    `json:"Production"`
	Website    string    `json:"Website"`
	Response   string    `json:"Response"`
	Error      string    `json:"Error"`
}

// Search for movies given a Title and year, Year is optional you can pass nil
func (api *OmdbApi) Search(query *QueryData) (*SearchResponse, error) {
	resp, err := api.requestAPI("search", query.Title, query.Year, query.SearchType)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	r := new(SearchResponse)
	err = json.NewDecoder(resp.Body).Decode(r)

	if err != nil {
		return nil, err
	}
	if r.Response == "False" {
		return r, errors.New(r.Error)
	}

	return r, nil
}

// MovieByTitle returns a MovieResult given Title
func (api *OmdbApi) MovieByTitle(query *QueryData) (*MovieResult, error) {
	resp, err := api.requestAPI("title", query.Title, query.Year, query.SearchType, query.Season,
		query.Episode)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	r := new(MovieResult)
	err = json.NewDecoder(resp.Body).Decode(r)

	if err != nil {
		return nil, err
	}
	if r.Response == "False" {
		return r, errors.New(r.Error)
	}
	return r, nil
}

// MovieByImdbID returns a MovieResult given a ImdbID ex:"tt2015381"
func (api *OmdbApi) MovieByImdbID(query *QueryData) (*MovieResult, error) {

	resp, err := api.requestAPI("id", query.ImdbId, query.Year, query.SearchType, query.Season, query.Episode)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	r := new(MovieResult)
	err = json.NewDecoder(resp.Body).Decode(r)

	if err != nil {
		return nil, err
	}
	if r.Response == "False" {
		return r, errors.New(r.Error)
	}
	return r, nil
}

// helper function to call the API
// param: apiCategory refers to which API we are calling. Can be "search", "title" or "id"
// Depending on that value, we will search by "t" or "s" or "i"
// param: params are the variadic list of params passed for that category
func (api *OmdbApi) requestAPI(apiCategory string, params ...string) (resp *http.Response, err error) {
	var URL *url.URL
	URL, err = url.Parse(baseURL)
	if err != nil {
		return nil, err
	}

	// Checking for invalid category
	if len(params) > 1 && params[2] != "" {
		if params[2] != MovieSearch &&
			params[2] != SeriesSearch &&
			params[2] != EpisodeSearch {
			return nil, errors.New("Invalid search category- " + params[2])
		}
	}
	URL.Path += "/"
	parameters := url.Values{}
	parameters.Add("apikey", api.apiKey)

	switch apiCategory {
	case "search":
		parameters.Add("s", params[0])
		parameters.Add("y", params[1])
		parameters.Add("type", params[2])
	case "title":
		parameters.Add("t", params[0])
		parameters.Add("y", params[1])
		parameters.Add("type", params[2])
		parameters.Add("Season", params[3])
		parameters.Add("Episode", params[4])
		parameters.Add("plot", plot)
		parameters.Add("tomatoes", tomatoes)
	case "id":
		parameters.Add("i", params[0])
		parameters.Add("type", params[2])
		parameters.Add("Season", params[3])
		parameters.Add("Episode", params[4])
		parameters.Add("plot", plot)
		parameters.Add("tomatoes", tomatoes)
	}

	URL.RawQuery = parameters.Encode()
	res, err := http.Get(URL.String())
	err = checkErr(res.StatusCode)
	if err != nil {
		return nil, err
	}
	return res, nil
}

func checkErr(status int) error {
	if status != 200 {
		return fmt.Errorf("Status Code %d received from OMDb", status)
	}
	return nil
}

// Stringer Interface for MovieResult
func (mr MovieResult) String() string {
	return fmt.Sprintf("#%s: %s (%s)", mr.ImdbID, mr.Title, mr.Year)
}

// Stringer Interface for SearchResult
func (sr SearchResult) String() string {
	return fmt.Sprintf("#%s: %s (%s) Type: %s", sr.ImdbID, sr.Title, sr.Year, sr.Type)
}