//! BB endpoint - GET /stock/technical/bb/{symbol}
//! Will be completed in Task 2

use crate::{errors::MarketDataError, models::BbResponse, rest::client::RestClient};

/// Request builder for Bollinger Bands (BB) endpoint
pub struct BbRequestBuilder<'a> {
    client: &'a RestClient,
    symbol: Option<String>,
    from: Option<String>,
    to: Option<String>,
    timeframe: Option<String>,
    period: Option<u32>,
    stddev: Option<f64>,
}

impl<'a> BbRequestBuilder<'a> {
    pub(crate) fn new(client: &'a RestClient) -> Self {
        Self {
            client,
            symbol: None,
            from: None,
            to: None,
            timeframe: None,
            period: None,
            stddev: None,
        }
    }

    /// Set the target symbol (e.g. `"2330"`).
    pub fn symbol(mut self, symbol: &str) -> Self {
        self.symbol = Some(symbol.to_string());
        self
    }

    /// Set the `from` date filter (ISO-8601 date, inclusive).
    pub fn from(mut self, from: &str) -> Self {
        self.from = Some(from.to_string());
        self
    }

    /// Set the `to` date filter (ISO-8601 date, inclusive).
    pub fn to(mut self, to: &str) -> Self {
        self.to = Some(to.to_string());
        self
    }

    /// Set the candle timeframe (e.g. `"1"`, `"5"`, `"D"`).
    pub fn timeframe(mut self, timeframe: &str) -> Self {
        self.timeframe = Some(timeframe.to_string());
        self
    }

    /// Set the indicator period (default per Fugle docs).
    pub fn period(mut self, period: u32) -> Self {
        self.period = Some(period);
        self
    }

    /// Set the standard deviation multiplier (typically 2.0)
    pub fn stddev(mut self, stddev: f64) -> Self {
        self.stddev = Some(stddev);
        self
    }

    /// Execute the request and deserialize the response.
    ///
    /// # Errors
    /// Returns [`MarketDataError::InvalidSymbol`] if no symbol was provided,
    /// [`MarketDataError::ConnectionError`] / [`MarketDataError::TimeoutError`]
    /// on transport failure, [`MarketDataError::ApiError`] on a non-2xx HTTP
    /// status, and [`MarketDataError::DeserializationError`] or
    /// [`MarketDataError::Other`] if the body fails to decode.
    pub fn send(self) -> Result<BbResponse, MarketDataError> {
        let symbol = self.symbol.ok_or_else(|| MarketDataError::InvalidSymbol {
            symbol: "(not provided)".to_string(),
        })?;

        let mut url = format!(
            "{}/stock/technical/bb/{}",
            self.client.get_base_url(),
            symbol
        );

        let mut query_params = Vec::new();
        if let Some(from) = self.from {
            query_params.push(format!("from={}", from));
        }
        if let Some(to) = self.to {
            query_params.push(format!("to={}", to));
        }
        if let Some(timeframe) = self.timeframe {
            query_params.push(format!("timeframe={}", timeframe));
        }
        if let Some(period) = self.period {
            query_params.push(format!("period={}", period));
        }
        if let Some(stddev) = self.stddev {
            query_params.push(format!("stddev={}", stddev));
        }

        if !query_params.is_empty() {
            url.push('?');
            url.push_str(&query_params.join("&"));
        }

        let request = self.client.agent().get(&url);
        let request = self.client.auth().apply_to_request(request);

        let response = self.client.execute(request)?;
        let bb_response: BbResponse = response
            .into_json()
            .map_err(|e| MarketDataError::Other(e.into()))?;

        Ok(bb_response)
    }
}
