//! IPC serialization round-trip tests (D-030 Layer 1: fixture-based).

use settled_reach_server::bridge::types::*;
use std::fs;

#[test]
fn observer_snapshot_roundtrip() {
    let snapshot = ObserverSnapshot {
        tick: 42,
        entities: vec![VisibleEntity {
            entity_id: 1,
            x: 10.0,
            y: 20.0,
            z: 0,
            kind: EntityKind::Npc,
        }],
    };

    let bytes = rmp_serde::to_vec_named(&snapshot).expect("serialize");
    let decoded: ObserverSnapshot = rmp_serde::from_slice(&bytes).expect("deserialize");

    assert_eq!(decoded.tick, 42);
    assert_eq!(decoded.entities.len(), 1);
    assert_eq!(decoded.entities[0].entity_id, 1);
}

#[test]
fn player_input_roundtrip() {
    let input = PlayerInput {
        tick: 100,
        action: PlayerAction::MoveNorth,
    };

    let bytes = rmp_serde::to_vec_named(&input).expect("serialize");
    let decoded: PlayerInput = rmp_serde::from_slice(&bytes).expect("deserialize");

    assert_eq!(decoded.tick, 100);
}

#[test]
fn empty_snapshot_roundtrip() {
    let snapshot = ObserverSnapshot {
        tick: 0,
        entities: vec![],
    };

    let bytes = rmp_serde::to_vec_named(&snapshot).expect("serialize");
    let decoded: ObserverSnapshot = rmp_serde::from_slice(&bytes).expect("deserialize");

    assert_eq!(decoded.tick, 0);
    assert!(decoded.entities.is_empty());
}

/// All PlayerAction variants must survive MessagePack round-trip (D-030 Layer 1)
#[test]
fn all_player_action_variants_roundtrip() {
    let actions = vec![
        PlayerAction::MoveNorth,
        PlayerAction::MoveSouth,
        PlayerAction::MoveEast,
        PlayerAction::MoveWest,
        PlayerAction::MoveNortheast,
        PlayerAction::MoveNorthwest,
        PlayerAction::MoveSoutheast,
        PlayerAction::MoveSouthwest,
        PlayerAction::Interact,
        PlayerAction::UsePerceptionMode("thermal".to_string()),
        PlayerAction::Pause,
        PlayerAction::Unpause,
    ];

    for action in actions {
        let input = PlayerInput {
            tick: 1,
            action: action.clone(),
        };
        let bytes = rmp_serde::to_vec_named(&input).expect("serialize");
        let decoded: PlayerInput = rmp_serde::from_slice(&bytes).expect("deserialize");
        assert_eq!(decoded.tick, 1);
        // Verify the variant survived by re-serializing and comparing bytes
        let re_bytes = rmp_serde::to_vec_named(&decoded).expect("re-serialize");
        assert_eq!(bytes, re_bytes, "round-trip mismatch for action variant");
    }
}

/// All .msgpack fixtures must deserialize without error (guards against corruption in git).
/// Snapshot fixtures deserialize as ObserverSnapshot, input_* as PlayerInput,
/// input_batch_* as Vec<PlayerInput>.
#[test]
fn all_fixtures_deserialize() {
    let fixture_dir = std::path::Path::new("../client/tests/fixtures/msgpack");
    assert!(
        fixture_dir.exists(),
        "Fixture directory not found: {}",
        fixture_dir.display()
    );

    let mut count = 0;
    for entry in fs::read_dir(fixture_dir).expect("read fixture dir") {
        let entry = entry.expect("read dir entry");
        let path = entry.path();
        if path.extension().and_then(|e| e.to_str()) != Some("msgpack") {
            continue;
        }
        let name = path.file_stem().unwrap().to_str().unwrap().to_string();
        let bytes = fs::read(&path).unwrap_or_else(|_| panic!("read fixture {}", name));

        if name.starts_with("snapshot") {
            rmp_serde::from_slice::<ObserverSnapshot>(&bytes)
                .unwrap_or_else(|e| panic!("deserialize snapshot fixture {}: {}", name, e));
        } else if name.starts_with("input_batch") {
            rmp_serde::from_slice::<Vec<PlayerInput>>(&bytes)
                .unwrap_or_else(|e| panic!("deserialize batch input fixture {}: {}", name, e));
        } else if name.starts_with("input") {
            rmp_serde::from_slice::<PlayerInput>(&bytes)
                .unwrap_or_else(|e| panic!("deserialize input fixture {}: {}", name, e));
        } else {
            panic!("unknown fixture naming convention: {}", name);
        }
        count += 1;
    }
    assert!(count > 0, "no fixtures found");
    eprintln!("Verified {} fixtures", count);
}

/// All EntityKind variants must survive MessagePack round-trip (D-030 Layer 1)
#[test]
fn all_entity_kind_variants_roundtrip() {
    let kinds = vec![
        EntityKind::Player,
        EntityKind::Npc,
        EntityKind::Object,
        EntityKind::Terrain,
    ];

    for (i, kind) in kinds.into_iter().enumerate() {
        let entity = VisibleEntity {
            entity_id: i as u64,
            x: 0.0,
            y: 0.0,
            z: 0,
            kind,
        };
        let snapshot = ObserverSnapshot {
            tick: 0,
            entities: vec![entity],
        };
        let bytes = rmp_serde::to_vec_named(&snapshot).expect("serialize");
        let decoded: ObserverSnapshot = rmp_serde::from_slice(&bytes).expect("deserialize");
        let re_bytes = rmp_serde::to_vec_named(&decoded).expect("re-serialize");
        assert_eq!(
            bytes, re_bytes,
            "round-trip mismatch for EntityKind variant"
        );
    }
}