use std::collections::HashMap;
use std::sync::{Arc, Mutex};

use async_trait::async_trait;
use domain::ports::{Clock, IdGenerator, LocalPath, ManagedTempStore};
use domain::{
    ManagedTempAllocation, ManagedTempError, ManagedTempGcReport, ManagedTempHandle,
    ManagedTempKind, ManagedTempLease, ManagedTempState, ProjectId,
};
use uuid::Uuid;

use application::{
    AllocateManagedTemp, AllocateManagedTempInput, AppError, ResolveManagedTemp,
    ResolveManagedTempInput, MANAGED_TEMP_DEFAULT_TTL_MS, MANAGED_TEMP_PURPOSE_MAX_CHARS,
};

struct FixedClock;

impl Clock for FixedClock {
    fn now_millis(&self) -> i64 {
        10_000
    }
}

struct FixedIds;

impl IdGenerator for FixedIds {
    fn new_uuid(&self) -> Uuid {
        Uuid::from_u128(0x1234)
    }
}

#[derive(Default)]
struct FakeManagedTempStore {
    allocations: Mutex<Vec<ManagedTempAllocation>>,
    leases: Mutex<HashMap<ManagedTempHandle, ManagedTempLease>>,
}

#[async_trait]
impl ManagedTempStore for FakeManagedTempStore {
    async fn allocate(
        &self,
        allocation: ManagedTempAllocation,
    ) -> Result<ManagedTempLease, ManagedTempError> {
        let lease = ManagedTempLease {
            handle: allocation.handle.clone(),
            kind: allocation.kind,
            owner_project_id: allocation.owner_project_id,
            purpose: allocation.purpose.clone(),
            path: LocalPath::new(format!("/managed/{}", allocation.handle.as_str())),
            state: ManagedTempState::Active,
            created_at_ms: allocation.created_at_ms,
            last_access_at_ms: allocation.created_at_ms,
            expires_at_ms: allocation.expires_at_ms,
            released_at_ms: None,
        };
        self.allocations.lock().unwrap().push(allocation);
        self.leases
            .lock()
            .unwrap()
            .insert(lease.handle.clone(), lease.clone());
        Ok(lease)
    }

    async fn resolve(
        &self,
        handle: &ManagedTempHandle,
        _now_ms: u64,
    ) -> Result<ManagedTempLease, ManagedTempError> {
        self.leases
            .lock()
            .unwrap()
            .get(handle)
            .cloned()
            .ok_or(ManagedTempError::NotFound)
    }

    async fn release(
        &self,
        handle: &ManagedTempHandle,
        now_ms: u64,
    ) -> Result<ManagedTempLease, ManagedTempError> {
        let mut leases = self.leases.lock().unwrap();
        let lease = leases.get_mut(handle).ok_or(ManagedTempError::NotFound)?;
        lease.state = ManagedTempState::Released;
        lease.released_at_ms = Some(now_ms);
        Ok(lease.clone())
    }

    async fn gc(&self, _now_ms: u64) -> Result<ManagedTempGcReport, ManagedTempError> {
        Ok(ManagedTempGcReport { deleted: 0 })
    }
}

#[tokio::test]
async fn allocate_uses_generated_opaque_handle_and_default_ttl() {
    let store = Arc::new(FakeManagedTempStore::default());
    let use_case = AllocateManagedTemp::new(
        Arc::clone(&store) as Arc<dyn ManagedTempStore>,
        Arc::new(FixedIds),
        Arc::new(FixedClock),
    );
    let owner = ProjectId::from_uuid(Uuid::from_u128(7));

    let output = use_case
        .execute(AllocateManagedTempInput {
            owner_project_id: Some(owner),
            kind: ManagedTempKind::Directory,
            purpose: "  shared scratch  ".to_owned(),
            ttl_ms: None,
        })
        .await
        .unwrap();

    assert_eq!(
        output.lease.handle.as_str(),
        "00000000-0000-0000-0000-000000001234"
    );
    assert_eq!(
        output.lease.path.as_str(),
        "/managed/00000000-0000-0000-0000-000000001234"
    );

    let allocations = store.allocations.lock().unwrap();
    assert_eq!(allocations.len(), 1);
    assert_eq!(allocations[0].owner_project_id, Some(owner));
    assert_eq!(allocations[0].purpose, "shared scratch");
    assert_eq!(allocations[0].created_at_ms, 10_000);
    assert_eq!(
        allocations[0].expires_at_ms,
        Some(10_000 + MANAGED_TEMP_DEFAULT_TTL_MS)
    );
}

#[tokio::test]
async fn allocate_rejects_empty_or_zero_ttl_and_bounds_purpose_metadata() {
    let store = Arc::new(FakeManagedTempStore::default());
    let use_case = AllocateManagedTemp::new(
        Arc::clone(&store) as Arc<dyn ManagedTempStore>,
        Arc::new(FixedIds),
        Arc::new(FixedClock),
    );

    let empty = use_case
        .execute(AllocateManagedTempInput {
            owner_project_id: None,
            kind: ManagedTempKind::File,
            purpose: "   ".to_owned(),
            ttl_ms: Some(1),
        })
        .await
        .unwrap_err();
    assert!(matches!(empty, AppError::Invalid(_)));

    let zero_ttl = use_case
        .execute(AllocateManagedTempInput {
            owner_project_id: None,
            kind: ManagedTempKind::File,
            purpose: "scratch".to_owned(),
            ttl_ms: Some(0),
        })
        .await
        .unwrap_err();
    assert!(matches!(zero_ttl, AppError::Invalid(_)));

    let overflow_ttl = use_case
        .execute(AllocateManagedTempInput {
            owner_project_id: None,
            kind: ManagedTempKind::File,
            purpose: "scratch".to_owned(),
            ttl_ms: Some(u64::MAX),
        })
        .await
        .unwrap_err();
    assert!(matches!(overflow_ttl, AppError::Invalid(_)));

    use_case
        .execute(AllocateManagedTempInput {
            owner_project_id: None,
            kind: ManagedTempKind::File,
            purpose: "x".repeat(MANAGED_TEMP_PURPOSE_MAX_CHARS + 10),
            ttl_ms: Some(5),
        })
        .await
        .unwrap();
    let allocations = store.allocations.lock().unwrap();
    assert_eq!(
        allocations[0].purpose.chars().count(),
        MANAGED_TEMP_PURPOSE_MAX_CHARS
    );
}

#[tokio::test]
async fn resolve_rejects_path_like_handle_before_store_call() {
    let store = Arc::new(FakeManagedTempStore::default());
    let use_case = ResolveManagedTemp::new(
        Arc::clone(&store) as Arc<dyn ManagedTempStore>,
        Arc::new(FixedClock),
    );

    let err = use_case
        .execute(ResolveManagedTempInput {
            handle: "../escape".to_owned(),
        })
        .await
        .unwrap_err();

    assert!(matches!(err, AppError::Invalid(_)));
}