use axum::{
    extract::State,
    http::StatusCode,
    response::{IntoResponse, Json},
    Extension,
};
use common::ProjectContext;
use serde::{Deserialize, Serialize};
use sqlx::Row;
use totp_rs::{Algorithm, Secret, TOTP};
use uuid::Uuid;
use crate::middleware::AuthContext;
use crate::handlers::AuthState;
use crate::utils::{generate_token_with_aal, issue_refresh_token};
use crate::models::{User, AmrEntry};

#[derive(Serialize)]
pub struct EnrollResponse {
    pub id: Uuid,
    pub type_: String,
    pub totp: TotpResponse,
}

#[derive(Serialize)]
pub struct TotpResponse {
    pub qr_code: String,
    pub secret: String,
    pub uri: String,
}

#[derive(Deserialize)]
pub struct MfaVerifyRequest {
    pub factor_id: Uuid,
    pub code: String,
    pub challenge_id: Option<Uuid>,
}

#[derive(Serialize)]
pub struct VerifyResponse {
    pub access_token: String,
    pub token_type: String,
    pub expires_in: i64,
    pub refresh_token: String,
    pub user: User,
}

#[derive(Serialize)]
pub struct ChallengeResponse {
    pub challenge_id: Uuid,
    pub expires_at: i64,
}

pub async fn enroll(
    State(state): State<AuthState>,
    Extension(auth_ctx): Extension<AuthContext>,
    Extension(project_ctx): Extension<ProjectContext>,
) -> Result<impl IntoResponse, (StatusCode, String)> {
    let user_id = auth_ctx.claims.as_ref()
        .and_then(|c| Uuid::parse_str(&c.sub).ok())
        .ok_or((StatusCode::UNAUTHORIZED, "Invalid user".to_string()))?;

    let secret = Secret::generate_secret();
    let totp = TOTP::new(
        Algorithm::SHA1,
        6,
        1,
        30,
        secret.to_bytes().unwrap(),
        Some(project_ctx.project_ref.clone()),
        auth_ctx.claims.as_ref().and_then(|c| c.email.clone()).unwrap_or("user".to_string()),
    ).unwrap();

    let secret_str = totp.get_secret_base32();
    let qr_code = totp.get_qr_base64().map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e))?;
    let uri = totp.get_url();

    let row = sqlx::query(
        "INSERT INTO auth.mfa_factors (user_id, factor_type, secret, status) VALUES ($1, 'totp', $2, 'unverified') RETURNING id"
    )
    .bind(user_id)
    .bind(&secret_str)
    .fetch_one(&state.db)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?;

    let factor_id: Uuid = row.get("id");

    Ok(Json(EnrollResponse {
        id: factor_id,
        type_: "totp".to_string(),
        totp: TotpResponse {
            qr_code,
            secret: secret_str,
            uri,
        }
    }))
}

pub async fn verify(
    State(state): State<AuthState>,
    Extension(auth_ctx): Extension<AuthContext>,
    Extension(project_ctx): Extension<ProjectContext>,
    Json(payload): Json<MfaVerifyRequest>,
) -> Result<impl IntoResponse, (StatusCode, String)> {
    let user_id = auth_ctx.claims.as_ref()
        .and_then(|c| Uuid::parse_str(&c.sub).ok())
        .ok_or((StatusCode::UNAUTHORIZED, "Invalid user".to_string()))?;

    let row = sqlx::query(
        "SELECT secret, status FROM auth.mfa_factors WHERE id = $1 AND user_id = $2"
    )
    .bind(payload.factor_id)
    .bind(user_id)
    .fetch_optional(&state.db)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?
    .ok_or((StatusCode::NOT_FOUND, "Factor not found".to_string()))?;

    let secret_str: String = row.get("secret");
    let status: String = row.get("status");

    let secret_bytes = base32::decode(base32::Alphabet::RFC4648 { padding: false }, &secret_str)
        .ok_or((StatusCode::INTERNAL_SERVER_ERROR, "Invalid secret format".to_string()))?;

    let totp = TOTP::new(
        Algorithm::SHA1,
        6,
        1,
        30,
        secret_bytes,
        None,
        "".to_string(),
    ).unwrap();

    let is_valid = totp.check_current(&payload.code).unwrap_or(false);

    if !is_valid {
        return Err((StatusCode::BAD_REQUEST, "Invalid code".to_string()));
    }

    if status == "unverified" {
        sqlx::query("UPDATE auth.mfa_factors SET status = 'verified', updated_at = now() WHERE id = $1")
            .bind(payload.factor_id)
            .execute(&state.db)
            .await
            .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?;
    }

    let _challenge_id = if let Some(cid) = payload.challenge_id {
        let challenge_row = sqlx::query(
            "SELECT created_at FROM auth.mfa_challenges WHERE id = $1 AND factor_id = $2"
        )
        .bind(cid)
        .bind(payload.factor_id)
        .fetch_optional(&state.db)
        .await
        .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?
        .ok_or((StatusCode::BAD_REQUEST, "Invalid challenge".to_string()))?;

        let created_at: chrono::DateTime<chrono::Utc> = challenge_row.get("created_at");
        let elapsed = chrono::Utc::now() - created_at;
        if elapsed.num_seconds() > 300 {
            return Err((StatusCode::BAD_REQUEST, "Challenge expired".to_string()));
        }

        sqlx::query("UPDATE auth.mfa_challenges SET verified_at = now() WHERE id = $1")
            .bind(cid)
            .execute(&state.db)
            .await
            .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?;

        cid
    } else {
        Uuid::new_v4()
    };

    let jwt_secret = project_ctx.jwt_secret.as_str();
    let user = sqlx::query_as::<_, User>("SELECT * FROM users WHERE id = $1")
        .bind(user_id)
        .fetch_optional(&state.db)
        .await
        .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?
        .ok_or((StatusCode::NOT_FOUND, "User not found".to_string()))?;

    let amr = vec![
        AmrEntry {
            method: "password".to_string(),
            timestamp: chrono::Utc::now().timestamp() as usize,
        },
        AmrEntry {
            method: "totp".to_string(),
            timestamp: chrono::Utc::now().timestamp() as usize,
        },
    ];

    let (token, expires_in, _) = generate_token_with_aal(
        user_id, 
        &user.email, 
        "authenticated", 
        jwt_secret, 
        "aal2",
        Some(amr)
    ).map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?;

    let refresh_token = issue_refresh_token(&state.db, user_id, Uuid::new_v4(), None).await
        .map_err(|(code, msg)| (StatusCode::from_u16(code.as_u16()).unwrap_or(StatusCode::INTERNAL_SERVER_ERROR), msg))?;

    Ok(Json(VerifyResponse {
        access_token: token,
        token_type: "bearer".to_string(),
        expires_in,
        refresh_token,
        user,
    }))
}

pub async fn challenge(
    State(state): State<AuthState>,
    Extension(auth_ctx): Extension<AuthContext>,
    Json(payload): Json<MfaVerifyRequest>,
) -> Result<impl IntoResponse, (StatusCode, String)> {
    let user_id = auth_ctx.claims.as_ref()
        .and_then(|c| Uuid::parse_str(&c.sub).ok())
        .ok_or((StatusCode::UNAUTHORIZED, "Invalid user".to_string()))?;

    let _row = sqlx::query(
        "SELECT id FROM auth.mfa_factors WHERE id = $1 AND user_id = $2 AND status = 'verified'"
    )
    .bind(payload.factor_id)
    .bind(user_id)
    .fetch_optional(&state.db)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?
    .ok_or((StatusCode::BAD_REQUEST, "Factor not found or not verified".to_string()))?;

    let challenge_id = Uuid::new_v4();
    sqlx::query(
        "INSERT INTO auth.mfa_challenges (id, factor_id, created_at) VALUES ($1, $2, now())"
    )
    .bind(challenge_id)
    .bind(payload.factor_id)
    .execute(&state.db)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?;

    let expires_at = chrono::Utc::now() + chrono::Duration::seconds(300);

    Ok(Json(ChallengeResponse {
        challenge_id,
        expires_at: expires_at.timestamp(),
    }))
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_verify_response_structure() {
        let response = VerifyResponse {
            access_token: "test_token".to_string(),
            token_type: "bearer".to_string(),
            expires_in: 3600,
            refresh_token: "refresh".to_string(),
            user: User {
                id: Uuid::new_v4(),
                email: "test@example.com".to_string(),
                encrypted_password: "hash".to_string(),
                created_at: chrono::Utc::now(),
                updated_at: chrono::Utc::now(),
                last_sign_in_at: None,
                raw_app_meta_data: serde_json::json!({}),
                raw_user_meta_data: serde_json::json!({}),
                is_super_admin: None,
                confirmed_at: None,
                email_confirmed_at: None,
                phone: None,
                phone_confirmed_at: None,
                confirmation_token: None,
                recovery_token: None,
                email_change_token_new: None,
                email_change: None,
                deleted_at: None,
            },
        };
        assert_eq!(response.token_type, "bearer");
        assert!(response.expires_in > 0);
    }

    #[test]
    fn test_challenge_response_structure() {
        let response = ChallengeResponse {
            challenge_id: Uuid::new_v4(),
            expires_at: 1234567890,
        };
        assert!(response.expires_at > 0);
    }
}