use axum::{extract::State, Json};
use serde::{Deserialize, Serialize};
use sqlx::Row;
use utoipa::ToSchema;

use crate::{error::ApiError, state::AppState};

// ─── Types ──────────────────────────────────────────────────────────────────

#[derive(Deserialize, ToSchema)]
pub struct QBittorrentAddRequest {
    pub url: String,
}

#[derive(Serialize, ToSchema)]
pub struct QBittorrentAddResponse {
    pub success: bool,
    pub message: String,
}

#[derive(Serialize, ToSchema)]
pub struct QBittorrentTestResponse {
    pub success: bool,
    pub message: String,
    pub version: Option<String>,
}

// ─── Config helper ──────────────────────────────────────────────────────────

#[derive(Deserialize)]
struct QBittorrentConfig {
    url: String,
    username: String,
    password: String,
}

async fn load_qbittorrent_config(
    pool: &sqlx::PgPool,
) -> Result<(String, String, String), ApiError> {
    let row = sqlx::query("SELECT value FROM app_settings WHERE key = 'qbittorrent'")
        .fetch_optional(pool)
        .await?;

    let row = row.ok_or_else(|| ApiError::bad_request("qBittorrent is not configured"))?;
    let value: serde_json::Value = row.get("value");
    let config: QBittorrentConfig = serde_json::from_value(value)
        .map_err(|e| ApiError::internal(format!("invalid qbittorrent config: {e}")))?;

    if config.url.is_empty() || config.username.is_empty() {
        return Err(ApiError::bad_request(
            "qBittorrent URL and username must be configured in settings",
        ));
    }

    let url = config.url.trim_end_matches('/').to_string();
    Ok((url, config.username, config.password))
}

// ─── Login helper ───────────────────────────────────────────────────────────

async fn qbittorrent_login(
    client: &reqwest::Client,
    base_url: &str,
    username: &str,
    password: &str,
) -> Result<String, ApiError> {
    let resp = client
        .post(format!("{base_url}/api/v2/auth/login"))
        .form(&[("username", username), ("password", password)])
        .send()
        .await
        .map_err(|e| ApiError::internal(format!("qBittorrent login request failed: {e}")))?;

    if !resp.status().is_success() {
        let status = resp.status();
        let text = resp.text().await.unwrap_or_default();
        return Err(ApiError::internal(format!(
            "qBittorrent login failed ({status}): {text}"
        )));
    }

    // Extract SID from Set-Cookie header
    let cookie_header = resp
        .headers()
        .get("set-cookie")
        .and_then(|v| v.to_str().ok())
        .unwrap_or("");

    let sid = cookie_header
        .split(';')
        .next()
        .and_then(|s| s.strip_prefix("SID="))
        .ok_or_else(|| ApiError::internal("Failed to get SID cookie from qBittorrent"))?
        .to_string();

    Ok(sid)
}

// ─── Handlers ───────────────────────────────────────────────────────────────

/// Add a torrent to qBittorrent
#[utoipa::path(
    post,
    path = "/qbittorrent/add",
    tag = "qbittorrent",
    request_body = QBittorrentAddRequest,
    responses(
        (status = 200, body = QBittorrentAddResponse),
        (status = 400, description = "Bad request or qBittorrent not configured"),
        (status = 401, description = "Unauthorized"),
        (status = 500, description = "qBittorrent connection error"),
    ),
    security(("Bearer" = []))
)]
pub async fn add_torrent(
    State(state): State<AppState>,
    Json(body): Json<QBittorrentAddRequest>,
) -> Result<Json<QBittorrentAddResponse>, ApiError> {
    if body.url.is_empty() {
        return Err(ApiError::bad_request("url is required"));
    }

    let (base_url, username, password) = load_qbittorrent_config(&state.pool).await?;

    let client = reqwest::Client::builder()
        .timeout(std::time::Duration::from_secs(10))
        .build()
        .map_err(|e| ApiError::internal(format!("failed to build HTTP client: {e}")))?;

    let sid = qbittorrent_login(&client, &base_url, &username, &password).await?;

    let resp = client
        .post(format!("{base_url}/api/v2/torrents/add"))
        .header("Cookie", format!("SID={sid}"))
        .form(&[("urls", &body.url)])
        .send()
        .await
        .map_err(|e| ApiError::internal(format!("qBittorrent add request failed: {e}")))?;

    if resp.status().is_success() {
        Ok(Json(QBittorrentAddResponse {
            success: true,
            message: "Torrent added to qBittorrent".to_string(),
        }))
    } else {
        let status = resp.status();
        let text = resp.text().await.unwrap_or_default();
        Ok(Json(QBittorrentAddResponse {
            success: false,
            message: format!("qBittorrent returned {status}: {text}"),
        }))
    }
}

/// Test connection to qBittorrent
#[utoipa::path(
    get,
    path = "/qbittorrent/test",
    tag = "qbittorrent",
    responses(
        (status = 200, body = QBittorrentTestResponse),
        (status = 400, description = "qBittorrent not configured"),
        (status = 401, description = "Unauthorized"),
    ),
    security(("Bearer" = []))
)]
pub async fn test_qbittorrent(
    State(state): State<AppState>,
) -> Result<Json<QBittorrentTestResponse>, ApiError> {
    let (base_url, username, password) = load_qbittorrent_config(&state.pool).await?;

    let client = reqwest::Client::builder()
        .timeout(std::time::Duration::from_secs(10))
        .build()
        .map_err(|e| ApiError::internal(format!("failed to build HTTP client: {e}")))?;

    let sid = match qbittorrent_login(&client, &base_url, &username, &password).await {
        Ok(sid) => sid,
        Err(e) => {
            return Ok(Json(QBittorrentTestResponse {
                success: false,
                message: format!("Login failed: {}", e.message),
                version: None,
            }));
        }
    };

    let resp = client
        .get(format!("{base_url}/api/v2/app/version"))
        .header("Cookie", format!("SID={sid}"))
        .send()
        .await;

    match resp {
        Ok(r) if r.status().is_success() => {
            let version = r.text().await.unwrap_or_default();
            Ok(Json(QBittorrentTestResponse {
                success: true,
                message: format!("Connected successfully ({})", version.trim()),
                version: Some(version.trim().to_string()),
            }))
        }
        Ok(r) => {
            let status = r.status();
            let text = r.text().await.unwrap_or_default();
            Ok(Json(QBittorrentTestResponse {
                success: false,
                message: format!("qBittorrent returned {status}: {text}"),
                version: None,
            }))
        }
        Err(e) => Ok(Json(QBittorrentTestResponse {
            success: false,
            message: format!("Connection failed: {e}"),
            version: None,
        })),
    }
}
