use anyhow::{bail, Result};
use reqwest::Client;
use serde_json::Value;
use std::time::{SystemTime, UNIX_EPOCH};

use super::models::*;

const BASE_URL: &str = "https://www.qobuz.com/api.json/0.2/";
const USER_AGENT: &str =
    "Dalvik/2.1.0 (Linux; U; Android 9; Nexus 6P Build/PQ3A.190801.002) QobuzMobileAndroid/9.7.0.3-b26022717";
const APP_VERSION: &str = "9.7.0.3";
pub const DEFAULT_APP_ID: &str = "312369995";
pub const DEFAULT_APP_SECRET: &str = "e79f8b9be485692b0e5f9dd895826368";

pub struct QobuzClient {
    http: Client,
    pub auth_token: Option<String>,
    app_id: String,
    app_secret: String,
}

impl QobuzClient {
    pub fn new() -> Result<Self> {
        Self::new_with_config(None, None)
    }

    pub fn new_with_config(app_id: Option<&str>, app_secret: Option<&str>) -> Result<Self> {
        let app_id = app_id.unwrap_or(DEFAULT_APP_ID).to_string();
        let app_secret = app_secret.unwrap_or(DEFAULT_APP_SECRET).to_string();

        let http = Client::builder()
            .user_agent(USER_AGENT)
            .default_headers({
                let mut h = reqwest::header::HeaderMap::new();
                h.insert("X-App-Id", app_id.parse()?);
                h.insert("X-App-Version", APP_VERSION.parse()?);
                h.insert("X-Device-Platform", "android".parse()?);
                h.insert("X-Device-Model", "Nexus 6P".parse()?);
                h.insert("X-Device-Os-Version", "9".parse()?);
                h
            })
            .build()?;

        Ok(Self {
            http,
            auth_token: None,
            app_id,
            app_secret,
        })
    }

    pub fn set_auth_token(&mut self, token: String) {
        self.auth_token = Some(token);
    }

    fn ts() -> u64 {
        SystemTime::now()
            .duration_since(UNIX_EPOCH)
            .unwrap()
            .as_secs()
    }

    /// Compute the request signature required by the Qobuz API.
    /// NOTE: MD5 is mandated by the Qobuz API protocol — not our choice.
    fn request_sig(&self, method: &str, params: &mut Vec<(&str, String)>, ts: u64) -> String {
        params.sort_by_key(|(k, _)| *k);
        let mut s = method.replace('/', "");
        for (k, v) in params.iter() {
            s.push_str(k);
            s.push_str(v);
        }
        s.push_str(&ts.to_string());
        s.push_str(&self.app_secret);
        format!("{:x}", md5::compute(s.as_bytes()))
    }

    fn url(&self, method: &str) -> String {
        format!("{}{}", BASE_URL, method)
    }

    async fn check_response(resp: reqwest::Response) -> Result<Value> {
        let status = resp.status();
        let body: Value = resp.json().await?;
        if !status.is_success() {
            let msg = body
                .get("message")
                .and_then(|m| m.as_str())
                .unwrap_or("unknown API error");
            bail!("HTTP {}: {}", status, msg);
        }
        Ok(body)
    }

    fn post_request(&self, method: &str) -> reqwest::RequestBuilder {
        let mut builder = self.http.post(self.url(method));
        builder = builder.query(&[("app_id", self.app_id.as_str())]);
        if let Some(token) = &self.auth_token {
            builder = builder.header("Authorization", format!("Bearer {}", token));
        }
        builder
    }

    fn get_request(&self, method: &str) -> reqwest::RequestBuilder {
        let mut builder = self.http.get(self.url(method));
        builder = builder.query(&[("app_id", self.app_id.as_str())]);
        if let Some(token) = &self.auth_token {
            builder = builder.header("Authorization", format!("Bearer {}", token));
        }
        builder
    }

    // --- Auth ---

    pub async fn login(&mut self, email: &str, password: &str) -> Result<OAuthLoginResponse> {
        match self.oauth2_login(email, password).await {
            Ok(r) => Ok(r),
            Err(_) => self.legacy_login(email, password).await,
        }
    }

    /// NOTE: Qobuz API requires credentials as GET query params — not our choice.
    async fn oauth2_login(&mut self, email: &str, password: &str) -> Result<OAuthLoginResponse> {
        let ts = Self::ts();
        let mut sign_params: Vec<(&str, String)> = vec![
            ("password", password.to_string()),
            ("username", email.to_string()),
        ];
        let sig = self.request_sig("oauth2login", &mut sign_params, ts);

        let resp = self
            .http
            .get(self.url("oauth2/login"))
            .query(&[
                ("app_id", self.app_id.as_str()),
                ("username", email),
                ("password", password),
                ("request_ts", ts.to_string().as_str()),
                ("request_sig", sig.as_str()),
            ])
            .send()
            .await?;

        let status = resp.status();
        let body: Value = resp.json().await?;
        if !status.is_success() {
            let msg = body.get("message").and_then(|m| m.as_str()).unwrap_or("login failed");
            bail!("oauth2 login failed ({}): {}", status, msg);
        }

        self.extract_and_store_token(serde_json::from_value(body)?)
    }

    async fn legacy_login(&mut self, email: &str, password: &str) -> Result<OAuthLoginResponse> {
        let ts = Self::ts();
        let mut sign_params: Vec<(&str, String)> = vec![
            ("email", email.to_string()),
            ("password", password.to_string()),
        ];
        let sig = self.request_sig("userlogin", &mut sign_params, ts);

        let resp = self
            .http
            .get(self.url("user/login"))
            .query(&[
                ("app_id", self.app_id.as_str()),
                ("email", email),
                ("password", password),
                ("request_ts", ts.to_string().as_str()),
                ("request_sig", sig.as_str()),
            ])
            .send()
            .await?;

        let status = resp.status();
        let body: Value = resp.json().await?;
        if !status.is_success() {
            let msg = body.get("message").and_then(|m| m.as_str()).unwrap_or("login failed");
            bail!("user login failed ({}): {}", status, msg);
        }

        self.extract_and_store_token(serde_json::from_value(body)?)
    }

    fn extract_and_store_token(&mut self, login: OAuthLoginResponse) -> Result<OAuthLoginResponse> {
        if let Some(token) = login
            .oauth2
            .as_ref()
            .and_then(|o| o.access_token.clone())
            .or_else(|| login.user_auth_token.clone())
        {
            self.auth_token = Some(token);
        }
        Ok(login)
    }

    // --- User ---

    pub async fn get_user(&self) -> Result<UserDto> {
        let resp = self.get_request("user/get").send().await?;
        let body = Self::check_response(resp).await?;
        let user: UserDto = serde_json::from_value(body["user"].clone())
            .or_else(|_| serde_json::from_value(body.clone()))?;
        Ok(user)
    }

    // --- Track ---

    pub async fn get_track(&self, track_id: i64) -> Result<TrackDto> {
        let resp = self
            .get_request("track/get")
            .query(&[("track_id", track_id.to_string())])
            .send()
            .await?;
        let body = Self::check_response(resp).await?;
        Ok(serde_json::from_value(body)?)
    }

    pub async fn get_track_url(&self, track_id: i64, format: Format) -> Result<TrackFileUrlDto> {
        let ts = Self::ts();
        let intent = "stream";
        let mut sign_params: Vec<(&str, String)> = vec![
            ("format_id", format.id().to_string()),
            ("intent", intent.to_string()),
            ("track_id", track_id.to_string()),
        ];
        let sig = self.request_sig("trackgetFileUrl", &mut sign_params, ts);

        let resp = self
            .get_request("track/getFileUrl")
            .query(&[
                ("track_id", track_id.to_string()),
                ("format_id", format.id().to_string()),
                ("intent", intent.to_string()),
                ("request_ts", ts.to_string()),
                ("request_sig", sig),
            ])
            .send()
            .await?;

        let body = Self::check_response(resp).await?;
        Ok(serde_json::from_value(body)?)
    }

    // --- Album ---

    pub async fn get_album(&self, album_id: &str) -> Result<AlbumDto> {
        let resp = self
            .get_request("album/get")
            .query(&[("album_id", album_id), ("limit", "50"), ("offset", "0")])
            .send()
            .await?;
        let body = Self::check_response(resp).await?;
        Ok(serde_json::from_value(body)?)
    }

    // --- Artist ---

    pub async fn get_artist(&self, artist_id: i64) -> Result<ArtistDto> {
        let resp = self
            .get_request("artist/get")
            .query(&[
                ("artist_id", artist_id.to_string()),
                ("extra", "albums".to_string()),
                ("albums_limit", "200".to_string()),
            ])
            .send()
            .await?;
        let body = Self::check_response(resp).await?;
        Ok(serde_json::from_value(body)?)
    }

    pub async fn get_artist_page(&self, artist_id: i64) -> Result<Value> {
        let resp = self
            .get_request("artist/page")
            .query(&[("artist_id", artist_id.to_string())])
            .send()
            .await?;
        Self::check_response(resp).await
    }

    // --- Search ---

    pub async fn search(&self, query: &str, offset: u32, limit: u32) -> Result<SearchCatalogDto> {
        let resp = self
            .get_request("catalog/search")
            .query(&[
                ("query", query),
                ("offset", &offset.to_string()),
                ("limit", &limit.to_string()),
            ])
            .send()
            .await?;
        let body = Self::check_response(resp).await?;
        Ok(serde_json::from_value(body)?)
    }

    // --- Favorites / Library ---

    pub async fn get_user_playlists(&self, offset: u32, limit: u32) -> Result<UserPlaylistsDto> {
        let resp = self
            .get_request("playlist/getUserPlaylists")
            .query(&[("offset", &offset.to_string()), ("limit", &limit.to_string())])
            .send()
            .await?;
        let body = Self::check_response(resp).await?;
        Ok(serde_json::from_value(body)?)
    }

    pub async fn get_playlist(&self, playlist_id: i64, offset: u32, limit: u32) -> Result<PlaylistDto> {
        let resp = self
            .get_request("playlist/get")
            .query(&[
                ("playlist_id", &playlist_id.to_string()),
                ("extra", &"tracks".to_string()),
                ("offset", &offset.to_string()),
                ("limit", &limit.to_string()),
            ])
            .send()
            .await?;
        let body = Self::check_response(resp).await?;
        Ok(serde_json::from_value(body)?)
    }

    pub async fn get_fav_tracks(&self, offset: u32, limit: u32) -> Result<SearchResultItems<TrackDto>> {
        let resp = self
            .get_request("favorite/getUserFavorites")
            .query(&[("type", "tracks"), ("offset", &offset.to_string()), ("limit", &limit.to_string())])
            .send()
            .await?;
        let body = Self::check_response(resp).await?;
        Ok(serde_json::from_value(body["tracks"].clone())?)
    }

    pub async fn get_fav_albums(&self, offset: u32, limit: u32) -> Result<SearchResultItems<AlbumDto>> {
        let resp = self
            .get_request("favorite/getUserFavorites")
            .query(&[("type", "albums"), ("offset", &offset.to_string()), ("limit", &limit.to_string())])
            .send()
            .await?;
        let body = Self::check_response(resp).await?;
        Ok(serde_json::from_value(body["albums"].clone())?)
    }

    pub async fn get_fav_artists(&self, offset: u32, limit: u32) -> Result<SearchResultItems<FavArtistDto>> {
        let resp = self
            .get_request("favorite/getUserFavorites")
            .query(&[("type", "artists"), ("offset", &offset.to_string()), ("limit", &limit.to_string())])
            .send()
            .await?;
        let body = Self::check_response(resp).await?;
        Ok(serde_json::from_value(body["artists"].clone())?)
    }

    // --- Playlist management ---

    pub async fn create_playlist(&self, name: &str) -> Result<PlaylistDto> {
        let resp = self
            .post_request("playlist/create")
            .form(&[("name", name), ("is_public", "false"), ("is_collaborative", "false")])
            .send()
            .await?;
        let body = Self::check_response(resp).await?;
        Ok(serde_json::from_value(body)?)
    }

    pub async fn add_track_to_playlist(&self, playlist_id: i64, track_id: i64) -> Result<()> {
        let resp = self
            .post_request("playlist/addTracks")
            .form(&[
                ("playlist_id", playlist_id.to_string()),
                ("track_ids",   track_id.to_string()),
                ("no_duplicate", "true".to_string()),
            ])
            .send()
            .await?;
        Self::check_response(resp).await?;
        Ok(())
    }

    pub async fn delete_playlist(&self, playlist_id: i64) -> Result<()> {
        let resp = self
            .get_request("playlist/delete")
            .query(&[("playlist_id", &playlist_id.to_string())])
            .send()
            .await?;
        Self::check_response(resp).await?;
        Ok(())
    }

    pub async fn delete_track_from_playlist(&self, playlist_id: i64, playlist_track_id: i64) -> Result<()> {
        let resp = self
            .post_request("playlist/deleteTracks")
            .form(&[
                ("playlist_id",        playlist_id.to_string()),
                ("playlist_track_ids", playlist_track_id.to_string()),
            ])
            .send()
            .await?;
        Self::check_response(resp).await?;
        Ok(())
    }

    pub async fn add_fav_track(&self, track_id: i64) -> Result<()> {
        let resp = self
            .get_request("favorite/create")
            .query(&[("type", "tracks"), ("track_ids", &track_id.to_string())])
            .send()
            .await?;
        Self::check_response(resp).await?;
        Ok(())
    }

    pub async fn remove_fav_track(&self, track_id: i64) -> Result<()> {
        let resp = self
            .get_request("favorite/delete")
            .query(&[("type", "tracks"), ("track_ids", &track_id.to_string())])
            .send()
            .await?;
        Self::check_response(resp).await?;
        Ok(())
    }

    pub async fn add_fav_album(&self, album_id: &str) -> Result<()> {
        let resp = self
            .get_request("favorite/create")
            .query(&[("type", "albums"), ("album_ids", album_id)])
            .send()
            .await?;
        Self::check_response(resp).await?;
        Ok(())
    }

    pub async fn remove_fav_album(&self, album_id: &str) -> Result<()> {
        let resp = self
            .get_request("favorite/delete")
            .query(&[("type", "albums"), ("album_ids", album_id)])
            .send()
            .await?;
        Self::check_response(resp).await?;
        Ok(())
    }
}