package musicbrainz

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"time"
)

const (
	baseURL   = "https://musicbrainz.org/ws/2"
	userAgent = "customTool/1.0 (djeeberjr@gmail.com)"
)

type MusicBrainzClient struct {
	httpClient    *http.Client
	userAgent     string
}

func NewMusicBrainzClient() *MusicBrainzClient {
	return &MusicBrainzClient{
		httpClient:    &http.Client{Timeout: 30 * time.Second},
		userAgent:     userAgent,
	}
}

type Artist struct {
	ID             string         `json:"id"`
	Name           string         `json:"name"`
	SortName       string         `json:"sort-name"`
	Type           string         `json:"type"`
	Country        string         `json:"country"`
	Disambiguation string         `json:"disambiguation"`
	LifeSpan       LifeSpan       `json:"life-span"`
	Tags           []Tag          `json:"tags"`
	Releases       []Release      `json:"releases"`
	ReleaseGroups  []ReleaseGroup `json:"release-groups"`
}

type Release struct {
	ID             string      `json:"id"`
	Title          string      `json:"title"`
	Status         string      `json:"status"`
	Date           string      `json:"date"`
	Country        string      `json:"country"`
	Disambiguation string      `json:"disambiguation"`
	ArtistCredit   []Credit    `json:"artist-credit"`
	LabelInfo      []LabelInfo `json:"label-info"`
	TrackCount     int         `json:"track-count"`
}

type ReleaseGroup struct {
	ID           string   `json:"id"`
	Title        string   `json:"title"`
	PrimaryType  string   `json:"primary-type"`
	FirstRelease string   `json:"first-release-date"`
	ArtistCredit []Credit `json:"artist-credit"`
}

type Recording struct {
	ID             string    `json:"id"`
	Title          string    `json:"title"`
	LengthInMS     int       `json:"length"`
	Disambiguation string    `json:"disambiguation"`
	ArtistCredit   []Credit  `json:"artist-credit"`
	Releases       []Release `json:"releases"`
	Tags           []Tag     `json:"tags"`
}

type Credit struct {
	Name       string `json:"name"`
	JoinPhrase string `json:"joinphrase"`
	Artist     Artist `json:"artist"`
}

type LabelInfo struct {
	CatalogNumber string `json:"catalog-number"`
	Label         struct {
		ID   string `json:"id"`
		Name string `json:"name"`
	} `json:"label"`
}

type LifeSpan struct {
	Begin string `json:"begin"`
	End   string `json:"end"`
	Ended bool   `json:"ended"`
}

type Tag struct {
	Name  string `json:"name"`
	Count int    `json:"count"`
}

type ArtistSearchResult struct {
	Created string   `json:"created"`
	Count   int      `json:"count"`
	Offset  int      `json:"offset"`
	Artists []Artist `json:"artists"`
}

type ReleaseSearchResult struct {
	Created  string    `json:"created"`
	Count    int       `json:"count"`
	Offset   int       `json:"offset"`
	Releases []Release `json:"releases"`
}

type RecordingSearchResult struct {
	Created    string      `json:"created"`
	Count      int         `json:"count"`
	Offset     int         `json:"offset"`
	Recordings []Recording `json:"recordings"`
}

type SearchOptions struct {
	Limit  int // max results (default 25, max 100)
	Offset int // results offset for pagination
}

func (o SearchOptions) params() url.Values {
	v := url.Values{}
	if o.Limit > 0 {
		v.Set("limit", fmt.Sprintf("%d", o.Limit))
	}
	if o.Offset > 0 {
		v.Set("offset", fmt.Sprintf("%d", o.Offset))
	}
	return v
}

func (c *MusicBrainzClient) SearchByISRC(isrc string, opts SearchOptions) (*RecordingSearchResult, error) {
	var result RecordingSearchResult
	err := c.search("recording", fmt.Sprintf("isrc:%s", isrc), opts, &result)
	return &result, err
}

func (c *MusicBrainzClient) SearchArtists(query string, opts SearchOptions) (*ArtistSearchResult, error) {
	var result ArtistSearchResult
	err := c.search("artist", query, opts, &result)
	return &result, err
}

func (c *MusicBrainzClient) SearchReleases(query string, opts SearchOptions) (*ReleaseSearchResult, error) {
	var result ReleaseSearchResult
	err := c.search("release", query, opts, &result)
	return &result, err
}

func (c *MusicBrainzClient) SearchRecordings(query string, opts SearchOptions) (*RecordingSearchResult, error) {
	var result RecordingSearchResult
	err := c.search("recording", query, opts, &result)
	return &result, err
}

func (c *MusicBrainzClient) GetArtist(mbid string, inc []string) (*Artist, error) {
	var artist Artist
	err := c.lookup("artist", mbid, inc, &artist)
	return &artist, err
}

func (c *MusicBrainzClient) GetRelease(mbid string, inc []string) (*Release, error) {
	var release Release
	err := c.lookup("release", mbid, inc, &release)
	return &release, err
}

func (c *MusicBrainzClient) GetRecording(mbid string, inc []string) (*Recording, error) {
	var recording Recording
	err := c.lookup("recording", mbid, inc, &recording)
	return &recording, err
}

func (c *MusicBrainzClient) search(entity, query string, opts SearchOptions, out any) error {
	params := opts.params()
	params.Set("query", query)
	params.Set("fmt", "json")

	endpoint := fmt.Sprintf("%s/%s?%s", baseURL, entity, params.Encode())
	return c.get(endpoint, out)
}

func (c *MusicBrainzClient) lookup(entity, mbid string, inc []string, out any) error {
	params := url.Values{"fmt": []string{"json"}}
	if len(inc) > 0 {
		incStr := ""
		for i, s := range inc {
			if i > 0 {
				incStr += "+"
			}
			incStr += s
		}
		params.Set("inc", incStr)
	}
	endpoint := fmt.Sprintf("%s/%s/%s?%s", baseURL, entity, mbid, params.Encode())
	return c.get(endpoint, out)
}

func (c *MusicBrainzClient) get(endpoint string, out any) error {
	req, err := http.NewRequest(http.MethodGet, endpoint, nil)
	if err != nil {
		return fmt.Errorf("build request: %w", err)
	}
	req.Header.Set("User-Agent", c.userAgent)
	req.Header.Set("Accept", "application/json")

	resp, err := c.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("http: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return fmt.Errorf("read body: %w", err)
	}

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("status %d: %s", resp.StatusCode, string(body))
	}

	if err := json.Unmarshal(body, out); err != nil {
		return fmt.Errorf("decode JSON: %w", err)
	}

	return nil
}