use std::str::FromStr;

use cm_domain::{AgentId, MessageId, SessionId, SessionKey, SessionKeyError};

fn sample() -> SessionKey {
    SessionKey {
        agent_id: AgentId::from_str("018f9c1e-8f2a-7c3b-9d4e-5f6a7b8c9d0e").unwrap(),
        shard: 3,
        session_id: SessionId::from_str("018f9c1e-9a1b-7c2d-8e3f-4a5b6c7d8e9f").unwrap(),
        message_id: MessageId::from_str("018f9c1e-ab2c-7d3e-9f4a-5b6c7d8e9f0a").unwrap(),
    }
}

#[test]
fn formats_to_spec_layout() {
    let key = sample();
    assert_eq!(
        key.to_string(),
        "agent:018f9c1e-8f2a-7c3b-9d4e-5f6a7b8c9d0e-claw-3\
         :session:018f9c1e-9a1b-7c2d-8e3f-4a5b6c7d8e9f\
         :018f9c1e-ab2c-7d3e-9f4a-5b6c7d8e9f0a"
    );
}

#[test]
fn parses_its_own_output() {
    let key = sample();
    let parsed = SessionKey::from_str(&key.to_string()).unwrap();
    assert_eq!(parsed, key);
}

#[test]
fn rejects_missing_agent_prefix() {
    let err = SessionKey::from_str(
        "claw:018f9c1e-8f2a-7c3b-9d4e-5f6a7b8c9d0e-claw-3\
         :session:018f9c1e-9a1b-7c2d-8e3f-4a5b6c7d8e9f\
         :018f9c1e-ab2c-7d3e-9f4a-5b6c7d8e9f0a",
    )
    .unwrap_err();
    assert!(matches!(err, SessionKeyError::Malformed(_)));
}

#[test]
fn rejects_missing_session_segment() {
    let err = SessionKey::from_str(
        "agent:018f9c1e-8f2a-7c3b-9d4e-5f6a7b8c9d0e-claw-3\
         :chat:018f9c1e-9a1b-7c2d-8e3f-4a5b6c7d8e9f\
         :018f9c1e-ab2c-7d3e-9f4a-5b6c7d8e9f0a",
    )
    .unwrap_err();
    assert!(matches!(err, SessionKeyError::Malformed(_)));
}

#[test]
fn rejects_non_numeric_shard() {
    let err = SessionKey::from_str(
        "agent:018f9c1e-8f2a-7c3b-9d4e-5f6a7b8c9d0e-claw-x\
         :session:018f9c1e-9a1b-7c2d-8e3f-4a5b6c7d8e9f\
         :018f9c1e-ab2c-7d3e-9f4a-5b6c7d8e9f0a",
    )
    .unwrap_err();
    assert!(matches!(err, SessionKeyError::InvalidShard(_)));
}

#[test]
fn rejects_invalid_agent_uuid() {
    let err = SessionKey::from_str(
        "agent:not-a-uuid-claw-3\
         :session:018f9c1e-9a1b-7c2d-8e3f-4a5b6c7d8e9f\
         :018f9c1e-ab2c-7d3e-9f4a-5b6c7d8e9f0a",
    )
    .unwrap_err();
    assert!(matches!(err, SessionKeyError::InvalidId(_)));
}

#[test]
fn rejects_trailing_garbage() {
    let mut s = sample().to_string();
    s.push_str(":extra");
    let err = SessionKey::from_str(&s).unwrap_err();
    assert!(matches!(err, SessionKeyError::Malformed(_)));
}

#[test]
fn serde_round_trips_as_string() {
    let key = sample();
    let json = serde_json::to_string(&key).unwrap();
    assert_eq!(json, format!("\"{key}\""));
    let back: SessionKey = serde_json::from_str(&json).unwrap();
    assert_eq!(back, key);
}

mod properties {
    use super::*;
    use proptest::prelude::*;

    fn arb_uuid() -> impl Strategy<Value = uuid::Uuid> {
        any::<u128>().prop_map(uuid::Uuid::from_u128)
    }

    proptest! {
        #[test]
        fn round_trips_for_any_ids(
            agent in arb_uuid(),
            session in arb_uuid(),
            message in arb_uuid(),
            shard in any::<u16>(),
        ) {
            let key = SessionKey {
                agent_id: AgentId::from(agent),
                shard,
                session_id: SessionId::from(session),
                message_id: MessageId::from(message),
            };
            let parsed = SessionKey::from_str(&key.to_string()).unwrap();
            prop_assert_eq!(parsed, key);
        }
    }
}