use anyhow::{Context, Result};
use reqwest::{Client, Response};

use crate::events::{Category, Peer, Torrent, TorrentFile, TorrentProperties, Tracker, TransferInfo};

/// qBittorrent Web API client with session cookie management.
#[derive(Clone)]
pub struct QbittorrentClient {
    client: Client,
    pub base_url: String,
    username: String,
    password: String,
    is_authenticated: bool,
}

impl QbittorrentClient {
    pub fn new(base_url: String, username: String, password: String) -> Self {
        let client = Client::builder()
            .cookie_store(true)
            .build()
            .expect("Failed to build HTTP client");

        Self {
            client,
            base_url,
            username,
            password,
            is_authenticated: false,
        }
    }

    /// Authenticate and store the session cookie.
    pub async fn login(&mut self) -> Result<()> {
        let url = format!("{}/api/v2/auth/login", self.base_url);
        let params = [
            ("username", self.username.as_str()),
            ("password", self.password.as_str()),
        ];

        let resp = self
            .client
            .post(&url)
            .form(&params)
            .send()
            .await
            .context("Login request failed")?;

        let status = resp.status();
        let body = resp.text().await.context("Failed to read login response")?;
        let body_trimmed = body.trim();

        if status.is_success() && (body_trimmed == "Ok." || status.as_u16() == 204) {
            self.is_authenticated = true;
            Ok(())
        } else if status.is_success() && body_trimmed == "Fails." {
            self.is_authenticated = false;
            anyhow::bail!("Authentication failed: invalid username or password")
        } else if status.as_u16() == 403 {
            self.is_authenticated = false;
            anyhow::bail!("Authentication failed: IP is banned (too many failed attempts)")
        } else {
            self.is_authenticated = false;
            anyhow::bail!(
                "Authentication failed (HTTP {}): {}",
                status,
                body_trimmed
            )
        }
    }

    pub fn is_authenticated(&self) -> bool {
        self.is_authenticated
    }

    pub fn reset_session(&mut self) {
        self.client = Client::builder()
            .cookie_store(true)
            .build()
            .expect("Failed to build HTTP client");
        self.is_authenticated = false;
    }

    /// Fetch the list of torrents.
    pub async fn get_torrents(&self) -> Result<Vec<Torrent>> {
        self.require_auth()?;
        let url = format!("{}/api/v2/torrents/info", self.base_url);
        let resp = self.client.get(&url).send().await?;
        if resp.status().as_u16() == 204 {
            return Ok(Vec::new());
        }
        self.handle_response(resp).await
    }

    /// Fetch global state, categories and tags from sync/maindata.
    /// Defensively parses every field to avoid crashing on unexpected types.
    pub async fn get_maindata_extras(&self) -> Result<(TransferInfo, Vec<Category>, Vec<String>)> {
        self.require_auth()?;
        let url = format!("{}/api/v2/sync/maindata?rid=0", self.base_url);
        let resp = self.client.get(&url).send().await?;

        if resp.status().as_u16() == 204 {
            return Ok((TransferInfo::default(), Vec::new(), Vec::new()));
        }

        if !resp.status().is_success() {
            let status = resp.status();
            let text = resp.text().await.unwrap_or_default();
            anyhow::bail!("HTTP {}: {}", status, text);
        }

        let data: serde_json::Value = resp.json().await?;

        // --- server_state ---
        let state = data.get("server_state").map(|s| {
            let dl = s.get("dl_info_speed")
                .and_then(|v| v.as_i64())
                .unwrap_or(0);
            let ul = s.get("up_info_speed")
                .and_then(|v| v.as_i64())
                .unwrap_or(0);
            let free = s.get("free_space_on_disk")
                .and_then(|v| v.as_i64())
                .unwrap_or(0);
            TransferInfo { dl_speed: dl, ul_speed: ul, free_space: free }
        }).unwrap_or_default();

        // --- categories ---
        let categories: Vec<Category> = data
            .get("categories")
            .and_then(|c| c.as_object())
            .map(|obj| {
                obj.values()
                    .filter_map(|v| serde_json::from_value(v.clone()).ok())
                    .collect()
            })
            .unwrap_or_default();

        // --- tags ---
        let tags: Vec<String> = match data.get("tags") {
            Some(serde_json::Value::Array(arr)) => arr
                .iter()
                .filter_map(|v| v.as_str().map(|s| s.to_string()))
                .collect(),
            Some(serde_json::Value::String(s)) if s.is_empty() => Vec::new(),
            Some(other) => {
                serde_json::from_value(other.clone()).unwrap_or_default()
            }
            None => Vec::new(),
        };

        Ok((state, categories, tags))
    }

    /// Pause (stop) torrents by hash.
    pub async fn pause_torrents(&self, hashes: &[String]) -> Result<()> {
        self.require_auth()?;
        let hashes_str = hashes.join("|");
        for endpoint in ["stop", "pause"] {
            let url = format!("{}/api/v2/torrents/{}", self.base_url, endpoint);
            let resp = self
                .client
                .post(&url)
                .form(&[("hashes", hashes_str.clone())])
                .send()
                .await?;
            if resp.status().is_success() {
                return Ok(());
            }
            if endpoint == "pause" && resp.status().as_u16() == 404 {
                continue;
            }
            let status = resp.status();
            let body = resp.text().await.unwrap_or_default();
            anyhow::bail!(
                "HTTP {} for pause (hash={}): {}",
                status,
                hashes_str,
                body
            );
        }
        Ok(())
    }

    /// Resume (start) torrents by hash.
    pub async fn resume_torrents(&self, hashes: &[String]) -> Result<()> {
        self.require_auth()?;
        let hashes_str = hashes.join("|");
        for endpoint in ["start", "resume"] {
            let url = format!("{}/api/v2/torrents/{}", self.base_url, endpoint);
            let resp = self
                .client
                .post(&url)
                .form(&[("hashes", hashes_str.clone())])
                .send()
                .await?;
            if resp.status().is_success() {
                return Ok(());
            }
            if endpoint == "resume" && resp.status().as_u16() == 404 {
                continue;
            }
            let status = resp.status();
            let body = resp.text().await.unwrap_or_default();
            anyhow::bail!(
                "HTTP {} for resume (hash={}): {}",
                status,
                hashes_str,
                body
            );
        }
        Ok(())
    }

    /// Delete torrents by hash.
    pub async fn delete_torrents(&self, hashes: &[String], delete_files: bool) -> Result<()> {
        self.require_auth()?;
        let url = format!("{}/api/v2/torrents/delete", self.base_url);
        let hashes_str = hashes.join("|");
        let resp = self
            .client
            .post(&url)
            .form(&[
                ("hashes", hashes_str.as_str()),
                ("deleteFiles", if delete_files { "true" } else { "false" }),
            ])
            .send()
            .await?;
        resp.error_for_status()?;
        Ok(())
    }

    /// Add torrent(s) from magnet URL(s) or torrent file URL(s).
    pub async fn add_torrents(&self, urls: &str) -> Result<()> {
        self.require_auth()?;
        let url = format!("{}/api/v2/torrents/add", self.base_url);
        let resp = self
            .client
            .post(&url)
            .form(&[("urls", urls)])
            .send()
            .await?;
        resp.error_for_status()?;
        Ok(())
    }

    /// Add torrent(s) with advanced options.
    pub async fn add_torrents_advanced(
        &self,
        urls: &str,
        save_path: &str,
        category: &str,
        tags: &[String],
        paused: bool,
        skip_checking: bool,
    ) -> Result<()> {
        self.require_auth()?;
        let url = format!("{}/api/v2/torrents/add", self.base_url);
        let mut params = vec![
            ("urls", urls.to_string()),
        ];
        if !save_path.is_empty() {
            params.push(("savepath", save_path.to_string()));
        }
        if !category.is_empty() {
            params.push(("category", category.to_string()));
        }
        if !tags.is_empty() {
            params.push(("tags", tags.join(",")));
        }
        if paused {
            params.push(("paused", "true".to_string()));
        }
        if skip_checking {
            params.push(("skip_checking", "true".to_string()));
        }
        let resp = self
            .client
            .post(&url)
            .form(&params)
            .send()
            .await?;
        resp.error_for_status()?;
        Ok(())
    }

    /// Add a torrent from a local .torrent file.
    pub async fn add_torrent_file(&self, file_path: &str) -> Result<()> {
        self.require_auth()?;
        let url = format!("{}/api/v2/torrents/add", self.base_url);

        let file_content = tokio::fs::read(file_path).await
            .with_context(|| format!("Failed to read torrent file: {}", file_path))?;
        let file_name = std::path::Path::new(file_path)
            .file_name()
            .and_then(|n| n.to_str())
            .unwrap_or("torrent.torrent");

        let part = reqwest::multipart::Part::bytes(file_content)
            .file_name(file_name.to_string());
        let form = reqwest::multipart::Form::new()
            .part("torrents", part);

        let resp = self
            .client
            .post(&url)
            .multipart(form)
            .send()
            .await?;
        resp.error_for_status()?;
        Ok(())
    }

    /// Toggle alternative speed limits.
    pub async fn toggle_speed_limits_mode(&self) -> Result<()> {
        self.require_auth()?;
        let url = format!("{}/api/v2/transfer/toggleSpeedLimitsMode", self.base_url);
        let resp = self.client.post(&url).send().await?;
        resp.error_for_status()?;
        Ok(())
    }

    /// Get current speed limits mode (true = alternative).
    pub async fn get_speed_limits_mode(&self) -> Result<bool> {
        self.require_auth()?;
        let url = format!("{}/api/v2/transfer/speedLimitsMode", self.base_url);
        let resp = self.client.get(&url).send().await?;
        let text = resp.text().await?;
        Ok(text.trim() == "1")
    }

    /// Fetch trackers for a given torrent hash.
    pub async fn get_torrent_trackers(&self, hash: &str) -> Result<Vec<Tracker>> {
        self.require_auth()?;
        let url = format!("{}/api/v2/torrents/trackers?hash={}", self.base_url, hash);
        let resp = self.client.get(&url).send().await?;
        self.handle_response(resp).await
    }

    /// Fetch files for a given torrent hash.
    pub async fn get_torrent_files(&self, hash: &str) -> Result<Vec<TorrentFile>> {
        self.require_auth()?;
        let url = format!("{}/api/v2/torrents/files?hash={}", self.base_url, hash);
        let resp = self.client.get(&url).send().await?;
        self.handle_response(resp).await
    }

    /// Fetch detailed properties for a given torrent hash.
    pub async fn get_torrent_properties(&self, hash: &str) -> Result<TorrentProperties> {
        self.require_auth()?;
        let url = format!("{}/api/v2/torrents/properties?hash={}", self.base_url, hash);
        let resp = self.client.get(&url).send().await?;

        if !resp.status().is_success() {
            let status = resp.status();
            let text = resp.text().await.unwrap_or_default();
            anyhow::bail!("HTTP {} for properties: {}", status, text);
        }

        let body = resp.text().await?;
        if body.trim().is_empty() {
            return Ok(TorrentProperties::default());
        }

        let props: TorrentProperties = serde_json::from_str(&body)
            .with_context(|| format!("Failed to parse properties JSON: {}", &body[..body.len().min(200)]))?;
        Ok(props)
    }

    /// Fetch peers for a given torrent hash.
    pub async fn get_torrent_peers(&self, hash: &str) -> Result<Vec<Peer>> {
        self.require_auth()?;
        let url = format!("{}/api/v2/sync/torrentPeers?hash={}&rid=0", self.base_url, hash);
        let resp = self.client.get(&url).send().await?;

        if !resp.status().is_success() {
            let status = resp.status();
            let text = resp.text().await.unwrap_or_default();
            anyhow::bail!("HTTP {} for peers: {}", status, text);
        }

        let body = resp.text().await?;
        if body.trim().is_empty() {
            return Ok(Vec::new());
        }

        // The response is {"peers": {"peer_id": {Peer}, ...}}
        let data: serde_json::Value = serde_json::from_str(&body)
            .with_context(|| format!("Failed to parse peers JSON: {}", &body[..body.len().min(200)]))?;
        let peers: Vec<Peer> = data
            .get("peers")
            .and_then(|p| p.as_object())
            .map(|obj| {
                obj.values()
                    .filter_map(|v| serde_json::from_value(v.clone()).ok())
                    .collect()
            })
            .unwrap_or_default();
        Ok(peers)
    }

    /// Recheck torrents by hash.
    pub async fn recheck_torrents(&self, hashes: &[String]) -> Result<()> {
        self.require_auth()?;
        let url = format!("{}/api/v2/torrents/recheck", self.base_url);
        let hashes_str = hashes.join("|");
        let resp = self
            .client
            .post(&url)
            .form(&[("hashes", hashes_str)])
            .send()
            .await?;
        resp.error_for_status()?;
        Ok(())
    }

    /// Relocate torrents to a new path.
    pub async fn relocate_torrents(&self, hashes: &[String], new_path: &str) -> Result<()> {
        self.require_auth()?;
        let url = format!("{}/api/v2/torrents/setLocation", self.base_url);
        let hashes_str = hashes.join("|");
        let resp = self
            .client
            .post(&url)
            .form(&[("hashes", hashes_str), ("location", new_path.to_string())])
            .send()
            .await?;
        resp.error_for_status()?;
        Ok(())
    }

    /// Set upload/download limits for torrents (bytes/s, -1 = unlimited).
    pub async fn set_torrent_limits(&self, hashes: &[String], dl_limit: i64, ul_limit: i64) -> Result<()> {
        self.require_auth()?;
        let hashes_str = hashes.join("|");
        if dl_limit >= 0 {
            let url = format!("{}/api/v2/torrents/setDownloadLimit", self.base_url);
            let resp = self
                .client
                .post(&url)
                .form(&[("hashes", hashes_str.clone()), ("limit", dl_limit.to_string())])
                .send()
                .await?;
            resp.error_for_status()?;
        }
        if ul_limit >= 0 {
            let url = format!("{}/api/v2/torrents/setUploadLimit", self.base_url);
            let resp = self
                .client
                .post(&url)
                .form(&[("hashes", hashes_str), ("limit", ul_limit.to_string())])
                .send()
                .await?;
            resp.error_for_status()?;
        }
        Ok(())
    }

    /// Set category for torrents.
    pub async fn set_category(&self, hashes: &[String], category: &str) -> Result<()> {
        self.require_auth()?;
        let url = format!("{}/api/v2/torrents/setCategory", self.base_url);
        let hashes_str = hashes.join("|");
        let resp = self
            .client
            .post(&url)
            .form(&[("hashes", hashes_str), ("category", category.to_string())])
            .send()
            .await?;
        resp.error_for_status()?;
        Ok(())
    }

    /// Create a new category.
    pub async fn create_category(&self, name: &str, save_path: &str) -> Result<()> {
        self.require_auth()?;
        let url = format!("{}/api/v2/torrents/createCategory", self.base_url);
        let resp = self
            .client
            .post(&url)
            .form(&[("category", name), ("savePath", save_path)])
            .send()
            .await?;
        resp.error_for_status()?;
        Ok(())
    }

    /// Delete categories.
    pub async fn delete_categories(&self, names: &[String]) -> Result<()> {
        self.require_auth()?;
        let url = format!("{}/api/v2/torrents/removeCategories", self.base_url);
        let categories = names.join("\n");
        let resp = self
            .client
            .post(&url)
            .form(&[("categories", categories)])
            .send()
            .await?;
        resp.error_for_status()?;
        Ok(())
    }

    /// Add tags to torrents.
    pub async fn add_tags(&self, hashes: &[String], tags: &[String]) -> Result<()> {
        self.require_auth()?;
        let url = format!("{}/api/v2/torrents/addTags", self.base_url);
        let hashes_str = hashes.join("|");
        let tags_str = tags.join(",");
        let resp = self
            .client
            .post(&url)
            .form(&[("hashes", hashes_str), ("tags", tags_str)])
            .send()
            .await?;
        resp.error_for_status()?;
        Ok(())
    }

    /// Create new tags.
    pub async fn create_tags(&self, tags: &[String]) -> Result<()> {
        self.require_auth()?;
        let url = format!("{}/api/v2/torrents/createTags", self.base_url);
        let tags_str = tags.join(",");
        let resp = self
            .client
            .post(&url)
            .form(&[("tags", tags_str)])
            .send()
            .await?;
        resp.error_for_status()?;
        Ok(())
    }

    /// Delete tags.
    pub async fn delete_tags(&self, tags: &[String]) -> Result<()> {
        self.require_auth()?;
        let url = format!("{}/api/v2/torrents/deleteTags", self.base_url);
        let tags_str = tags.join(",");
        let resp = self
            .client
            .post(&url)
            .form(&[("tags", tags_str)])
            .send()
            .await?;
        resp.error_for_status()?;
        Ok(())
    }

    /// Set file priority for a torrent.
    pub async fn set_file_priority(&self, hash: &str, file_ids: &[i64], priority: i64) -> Result<()> {
        self.require_auth()?;
        let url = format!("{}/api/v2/torrents/filePrio", self.base_url);
        let ids = file_ids.iter().map(|i| i.to_string()).collect::<Vec<_>>().join(",");
        let prio = priority.to_string();
        let resp = self
            .client
            .post(&url)
            .form(&[("hash", hash), ("id", ids.as_str()), ("priority", prio.as_str())])
            .send()
            .await?;
        resp.error_for_status()?;
        Ok(())
    }

    fn require_auth(&self) -> Result<()> {
        if !self.is_authenticated {
            anyhow::bail!("Not authenticated")
        }
        Ok(())
    }

    async fn handle_response<T: serde::de::DeserializeOwned>(&self, resp: Response) -> Result<T> {
        if resp.status().is_success() {
            let json = resp.json::<T>().await?;
            Ok(json)
        } else {
            let status = resp.status();
            let text = resp.text().await.unwrap_or_default();
            anyhow::bail!("HTTP {}: {}", status, text)
        }
    }
}