use crate::common::UserClaims;
#[cfg(feature = "ssr")]
use jsonwebtoken::{DecodingKey, jwk::JwkSet};
use leptos::prelude::*;

#[cfg(feature = "ssr")]
pub async fn fetch_jwks(user_pool_id: String, region: String) -> Result<JwkSet, ServerFnError> {
    let request_url = format!(
        "https://cognito-idp.{}.amazonaws.com/{}/.well-known/jwks.json",
        region, user_pool_id
    );

    let jwks = reqwest::get(&request_url).await?.json::<JwkSet>().await?;

    Ok(jwks)
}

/// Validates a JWT, and, if successful, decodes it into a series of user claims.
#[cfg(feature = "ssr")]
pub async fn validate_and_get_token_info(
    token: String,
    pool_id: impl Into<String>,
    pool_region: impl Into<String>
) -> Result<UserClaims, ServerFnError> {
    use jsonwebtoken::{Algorithm, Validation, decode};

    let pool_id = pool_id.into();

    leptos::logging::debug_log!("Validating token using group {}", pool_id);

    // let jwks = fetch_jwks("us-east-1_Lfjuy5zaM".into(), "us-east-1".into()).await?;
    let jwks = fetch_jwks(pool_id, pool_region.into()).await?;

    let validation = Validation::new(Algorithm::RS256);
    // validation.set_audience(&["scholarships-rs"]);

    let header = jsonwebtoken::decode_header(&token)
        .map_err(|e| ServerFnError::new(format!("Invalid token header: {e}")))?;

    let kid = header
        .kid
        .ok_or_else(|| ServerFnError::new("Missing kid header"))?;

    let jwk = jwks
        .find(&kid)
        .ok_or_else(|| ServerFnError::new("Couldn't find matching key in JWKS"))?;

    leptos::logging::debug_log!("Parsing token: {:?}", token);

    let token_data = decode::<UserClaims>(&token, &DecodingKey::from_jwk(&jwk)?, &validation)
        .map_err(|err| ServerFnError::new(format!("Invalid token found: {err}")))?;

    if token_data.claims.token_use != "access" {
        return Err(ServerFnError::new("Token type mismatch"));
    }

    Ok(token_data.claims)
}