// file: kb_lib/src/db/dtos/pair.rs

//! Normalized pair DTO.

/// Application-facing normalized pair DTO.
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
pub struct PairDto {
    /// Optional numeric primary key.
    pub id: std::option::Option<i64>,
    /// Related DEX id.
    pub dex_id: i64,
    /// Related pool id.
    pub pool_id: i64,
    /// Base token id.
    pub base_token_id: i64,
    /// Quote token id.
    pub quote_token_id: i64,
    /// Optional display symbol.
    pub symbol: std::option::Option<std::string::String>,
    /// First seen timestamp.
    pub first_seen_at: chrono::DateTime<chrono::Utc>,
    /// Update timestamp.
    pub updated_at: chrono::DateTime<chrono::Utc>,
}

impl PairDto {
    /// Creates a new pair DTO.
    pub fn new(
        dex_id: i64,
        pool_id: i64,
        base_token_id: i64,
        quote_token_id: i64,
        symbol: std::option::Option<std::string::String>,
    ) -> Self {
        let now = chrono::Utc::now();
        return Self {
            id: None,
            dex_id,
            pool_id,
            base_token_id,
            quote_token_id,
            symbol,
            first_seen_at: now,
            updated_at: now,
        };
    }
}

impl TryFrom<crate::PairEntity> for PairDto {
    type Error = crate::Error;

    fn try_from(entity: crate::PairEntity) -> Result<Self, Self::Error> {
        let first_seen_at_result = chrono::DateTime::parse_from_rfc3339(&entity.first_seen_at);
        let first_seen_at = match first_seen_at_result {
            Ok(first_seen_at) => first_seen_at.with_timezone(&chrono::Utc),
            Err(error) => {
                return Err(crate::Error::Db(format!(
                    "cannot parse pair first_seen_at '{}': {}",
                    entity.first_seen_at, error
                )));
            },
        };
        let updated_at_result = chrono::DateTime::parse_from_rfc3339(&entity.updated_at);
        let updated_at = match updated_at_result {
            Ok(updated_at) => updated_at.with_timezone(&chrono::Utc),
            Err(error) => {
                return Err(crate::Error::Db(format!(
                    "cannot parse pair updated_at '{}': {}",
                    entity.updated_at, error
                )));
            },
        };
        return Ok(Self {
            id: Some(entity.id),
            dex_id: entity.dex_id,
            pool_id: entity.pool_id,
            base_token_id: entity.base_token_id,
            quote_token_id: entity.quote_token_id,
            symbol: entity.symbol,
            first_seen_at,
            updated_at,
        });
    }
}
