falsegreen-agent 0.1.2

use std::fmt;
use std::path::Path;
use std::thread;
use std::time::{Duration, Instant};

use serde::{Deserialize, Serialize};
use serde_json::{Value, json};
use thiserror::Error;

use crate::workspace::Workspace;

#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum FalseGreenVerdict {
    Accepted,
    Failed,
    Incomplete,
    InsufficientEvidence,
    Invalid,
}

/// Completion permission is independent from the canonical verification result.
/// Both flags must be true before the harness may enter `Completed`.
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Serialize, Deserialize)]
pub struct CompletionAuthority {
    #[serde(default)]
    pub authority_ready: bool,
    #[serde(default)]
    pub may_claim_complete: bool,
}

impl CompletionAuthority {
    #[must_use]
    pub const fn permits_completion(self) -> bool {
        self.authority_ready && self.may_claim_complete
    }
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct FalseGreenResult {
    #[serde(alias = "verdict")]
    pub verification: FalseGreenVerdict,
    #[serde(alias = "canonical_status")]
    pub verification_status: String,
    #[serde(default)]
    pub completion_authority: CompletionAuthority,
    pub repairable: bool,
    pub candidate_sha256: String,
    pub authoritative_source_sha256: Option<String>,
    pub run_id: Option<String>,
    pub evidence: Value,
}

impl FalseGreenResult {
    #[must_use]
    pub fn accepted(candidate_sha256: impl Into<String>) -> Self {
        Self {
            verification: FalseGreenVerdict::Accepted,
            verification_status: "accepted".to_owned(),
            completion_authority: CompletionAuthority {
                authority_ready: true,
                may_claim_complete: true,
            },
            repairable: false,
            candidate_sha256: candidate_sha256.into(),
            authoritative_source_sha256: None,
            run_id: None,
            evidence: json!({"status": "accepted"}),
        }
    }

    #[must_use]
    pub fn accepted_awaiting_authority(candidate_sha256: impl Into<String>) -> Self {
        Self {
            verification: FalseGreenVerdict::Accepted,
            verification_status: "accepted".to_owned(),
            completion_authority: CompletionAuthority::default(),
            repairable: false,
            candidate_sha256: candidate_sha256.into(),
            authoritative_source_sha256: None,
            run_id: None,
            evidence: json!({"status": "accepted"}),
        }
    }

    #[must_use]
    pub fn failed(candidate_sha256: impl Into<String>, evidence: Value) -> Self {
        Self {
            verification: FalseGreenVerdict::Failed,
            verification_status: "failed".to_owned(),
            completion_authority: CompletionAuthority::default(),
            repairable: true,
            candidate_sha256: candidate_sha256.into(),
            authoritative_source_sha256: None,
            run_id: None,
            evidence,
        }
    }

    #[must_use]
    pub fn permits_completion(&self) -> bool {
        self.verification == FalseGreenVerdict::Accepted
            && self.completion_authority.permits_completion()
    }
}

#[derive(Debug, Error)]
pub enum FalseGreenError {
    #[error(transparent)]
    Client(#[from] falsegreen_core::ClientError),
    #[error("canonical FalseGreen result has no string status")]
    MissingStatus,
    #[error("canonical FalseGreen pending result has no run identity")]
    MissingRunIdentity,
    #[error("canonical FalseGreen pending run identity changed")]
    RunIdentityChanged,
    #[error("canonical FalseGreen verification timed out")]
    Timeout,
    #[error("canonical FalseGreen repair evidence is unavailable")]
    MissingRepairEvidence,
}

pub trait FalseGreenVerifier {
    fn verify(
        &mut self,
        workspace: &Workspace,
        candidate_sha256: &str,
    ) -> Result<FalseGreenResult, FalseGreenError>;

    fn prepare_repair(&mut self, _workspace: &Workspace) -> Result<Value, FalseGreenError> {
        Ok(Value::Null)
    }
}

trait CanonicalClient {
    fn check_completion(
        &self,
        workspace_root: &Path,
        task_id: &str,
    ) -> Result<Value, FalseGreenError>;

    fn authority_status(&self, task_id: &str) -> Result<Value, FalseGreenError>;
}

impl CanonicalClient for falsegreen_core::Client {
    fn check_completion(
        &self,
        workspace_root: &Path,
        task_id: &str,
    ) -> Result<Value, FalseGreenError> {
        Ok(self
            .check_completion(workspace_root, task_id)?
            .into_payload())
    }

    fn authority_status(&self, task_id: &str) -> Result<Value, FalseGreenError> {
        Ok(self.authority_status(task_id)?.into_payload())
    }
}

/// In-process adapter for the canonical FalseGreen Rust client.
///
/// This adapter submits source through the pinned Core library. It never runs a
/// local executable and never converts model or local-test claims into
/// acceptance.
pub struct EmbeddedFalseGreenVerifier {
    client: Box<dyn CanonicalClient>,
    task_id: String,
    verification_timeout: Duration,
    poll_interval: Duration,
    repair_evidence: Option<Value>,
}

impl EmbeddedFalseGreenVerifier {
    /// Use the session established by the standalone `falsegreen login`
    /// command without spawning that binary at runtime.
    pub fn from_stored_session(
        task_id: impl Into<String>,
        verification_timeout: Duration,
    ) -> Result<Self, FalseGreenError> {
        Ok(Self {
            client: Box::new(falsegreen_core::Client::from_stored_session()?),
            task_id: task_id.into(),
            verification_timeout,
            poll_interval: Duration::from_millis(250),
            repair_evidence: None,
        })
    }

    #[cfg(test)]
    fn with_client(task_id: impl Into<String>, client: impl CanonicalClient + 'static) -> Self {
        Self {
            client: Box::new(client),
            task_id: task_id.into(),
            verification_timeout: Duration::from_secs(1),
            poll_interval: Duration::ZERO,
            repair_evidence: None,
        }
    }

    fn completion_decision(&self, workspace_root: &Path) -> Result<Value, FalseGreenError> {
        let started = Instant::now();
        let mut pending_run_id: Option<String> = None;
        loop {
            let decision = self
                .client
                .check_completion(workspace_root, &self.task_id)?;
            let status = decision
                .get("status")
                .and_then(Value::as_str)
                .ok_or(FalseGreenError::MissingStatus)?;
            if !pending_status(status) {
                return Ok(decision);
            }

            let run_id = decision
                .get("run_id")
                .and_then(Value::as_str)
                .ok_or(FalseGreenError::MissingRunIdentity)?;
            if pending_run_id
                .as_deref()
                .is_some_and(|expected| expected != run_id)
            {
                return Err(FalseGreenError::RunIdentityChanged);
            }
            pending_run_id.get_or_insert_with(|| run_id.to_owned());

            let elapsed = started.elapsed();
            if elapsed >= self.verification_timeout {
                return Err(FalseGreenError::Timeout);
            }
            thread::sleep(
                self.poll_interval
                    .min(self.verification_timeout.saturating_sub(elapsed)),
            );
        }
    }
}

impl fmt::Debug for EmbeddedFalseGreenVerifier {
    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
        formatter
            .debug_struct("EmbeddedFalseGreenVerifier")
            .field("task_id", &self.task_id)
            .field("verification_timeout", &self.verification_timeout)
            .field("repair_evidence", &self.repair_evidence)
            .finish_non_exhaustive()
    }
}

impl FalseGreenVerifier for EmbeddedFalseGreenVerifier {
    fn verify(
        &mut self,
        workspace: &Workspace,
        candidate_sha256: &str,
    ) -> Result<FalseGreenResult, FalseGreenError> {
        let decision = self.completion_decision(workspace.root())?;
        let status = decision
            .get("status")
            .and_then(Value::as_str)
            .ok_or(FalseGreenError::MissingStatus)?
            .to_owned();
        let authority = self.client.authority_status(&self.task_id)?;
        let repairable = explicit_true(&decision, "repair_authorized");
        self.repair_evidence = repairable.then(|| decision.clone());

        let verification = match status.as_str() {
            "accepted" => FalseGreenVerdict::Accepted,
            "failed" | "unsafe" => FalseGreenVerdict::Failed,
            "incomplete" => FalseGreenVerdict::Incomplete,
            "insufficient_evidence" => FalseGreenVerdict::InsufficientEvidence,
            _ => FalseGreenVerdict::Invalid,
        };
        let completion_authority = CompletionAuthority {
            authority_ready: explicit_true(&authority, "authority_ready"),
            may_claim_complete: explicit_true(&authority, "may_claim_complete"),
        };
        Ok(FalseGreenResult {
            verification,
            verification_status: status,
            completion_authority,
            repairable,
            candidate_sha256: candidate_sha256.to_owned(),
            authoritative_source_sha256: source_sha256(&decision),
            run_id: decision
                .get("run_id")
                .and_then(Value::as_str)
                .map(str::to_owned),
            evidence: json!({
                "completion_decision": decision,
                "authority_status": authority
            }),
        })
    }

    fn prepare_repair(&mut self, _workspace: &Workspace) -> Result<Value, FalseGreenError> {
        self.repair_evidence
            .take()
            .ok_or(FalseGreenError::MissingRepairEvidence)
    }
}

fn explicit_true(payload: &Value, name: &str) -> bool {
    payload.get(name).and_then(Value::as_bool) == Some(true)
}

fn pending_status(status: &str) -> bool {
    matches!(
        status,
        "QUEUED" | "CLAIMED" | "EXECUTING" | "RUNNING" | "queued" | "running"
    )
}

fn source_sha256(payload: &Value) -> Option<String> {
    payload
        .get("source_sha256")
        .or_else(|| payload.get("source_artifact_sha256"))
        .and_then(Value::as_str)
        .map(str::to_owned)
}

#[cfg(test)]
mod tests {
    use std::cell::RefCell;
    use std::collections::VecDeque;
    use std::path::Path;
    use std::rc::Rc;

    use serde_json::{Value, json};

    use crate::workspace::Workspace;
    use crate::workspace::tests::git_fixture;

    use super::{
        CanonicalClient, CompletionAuthority, EmbeddedFalseGreenVerifier, FalseGreenError,
        FalseGreenVerdict, FalseGreenVerifier,
    };

    struct ScriptedClient {
        checks: RefCell<VecDeque<Value>>,
        statuses: RefCell<VecDeque<Value>>,
        calls: Rc<RefCell<Vec<String>>>,
    }

    impl ScriptedClient {
        fn new(check: Value, status: Value) -> (Self, Rc<RefCell<Vec<String>>>) {
            Self::with_checks(vec![check], status)
        }

        fn with_checks(checks: Vec<Value>, status: Value) -> (Self, Rc<RefCell<Vec<String>>>) {
            let calls = Rc::new(RefCell::new(Vec::new()));
            (
                Self {
                    checks: RefCell::new(VecDeque::from(checks)),
                    statuses: RefCell::new(VecDeque::from([status])),
                    calls: Rc::clone(&calls),
                },
                calls,
            )
        }
    }

    impl CanonicalClient for ScriptedClient {
        fn check_completion(
            &self,
            workspace_root: &Path,
            task_id: &str,
        ) -> Result<Value, FalseGreenError> {
            assert!(workspace_root.is_dir());
            self.calls.borrow_mut().push(format!("check:{task_id}"));
            Ok(self.checks.borrow_mut().pop_front().expect("check result"))
        }

        fn authority_status(&self, task_id: &str) -> Result<Value, FalseGreenError> {
            self.calls.borrow_mut().push(format!("status:{task_id}"));
            Ok(self
                .statuses
                .borrow_mut()
                .pop_front()
                .expect("status result"))
        }
    }

    fn verify_shape(
        decision: Value,
        authority: Value,
    ) -> (super::FalseGreenResult, EmbeddedFalseGreenVerifier) {
        let directory = git_fixture();
        let workspace = Workspace::open(directory.path()).expect("workspace");
        let (client, _) = ScriptedClient::new(decision, authority);
        let mut verifier = EmbeddedFalseGreenVerifier::with_client("task_1", client);
        let result = verifier.verify(&workspace, "candidate").expect("verify");
        (result, verifier)
    }

    #[test]
    fn canonical_check_and_status_are_called_in_process() {
        let directory = git_fixture();
        let workspace = Workspace::open(directory.path()).expect("workspace");
        let (client, calls) = ScriptedClient::new(
            json!({"task_id": "task_1", "status": "accepted"}),
            json!({
                "task_id": "task_1",
                "status": "accepted",
                "authority_ready": true,
                "may_claim_complete": true
            }),
        );
        let mut verifier = EmbeddedFalseGreenVerifier::with_client("task_1", client);

        let result = verifier.verify(&workspace, "candidate").expect("verify");

        assert_eq!(&*calls.borrow(), &["check:task_1", "status:task_1"]);
        assert!(result.permits_completion());
    }

    #[test]
    fn hosted_pending_run_is_polled_without_changing_run_identity() {
        let directory = git_fixture();
        let workspace = Workspace::open(directory.path()).expect("workspace");
        let (client, calls) = ScriptedClient::with_checks(
            vec![
                json!({"task_id": "task_1", "status": "QUEUED", "run_id": "run_1"}),
                json!({"task_id": "task_1", "status": "EXECUTING", "run_id": "run_1"}),
                json!({"task_id": "task_1", "status": "accepted", "run_id": "result_1"}),
            ],
            json!({
                "task_id": "task_1",
                "status": "accepted",
                "authority_ready": true,
                "may_claim_complete": true
            }),
        );
        let mut verifier = EmbeddedFalseGreenVerifier::with_client("task_1", client);

        let result = verifier.verify(&workspace, "candidate").expect("verify");

        assert_eq!(
            &*calls.borrow(),
            &[
                "check:task_1",
                "check:task_1",
                "check:task_1",
                "status:task_1"
            ]
        );
        assert!(result.permits_completion());
        assert_eq!(result.run_id.as_deref(), Some("result_1"));
    }

    #[test]
    fn hosted_pending_run_identity_cannot_change_during_polling() {
        let directory = git_fixture();
        let workspace = Workspace::open(directory.path()).expect("workspace");
        let (client, _) = ScriptedClient::with_checks(
            vec![
                json!({"task_id": "task_1", "status": "QUEUED", "run_id": "run_1"}),
                json!({"task_id": "task_1", "status": "EXECUTING", "run_id": "run_2"}),
            ],
            json!({"task_id": "task_1", "status": "accepted"}),
        );
        let mut verifier = EmbeddedFalseGreenVerifier::with_client("task_1", client);

        assert!(matches!(
            verifier.verify(&workspace, "candidate"),
            Err(FalseGreenError::RunIdentityChanged)
        ));
    }

    #[test]
    fn accepted_verification_remains_accepted_while_awaiting_authority() {
        let (result, _) = verify_shape(
            json!({"task_id": "task_1", "status": "accepted"}),
            json!({
                "task_id": "task_1",
                "status": "accepted",
                "authority_ready": false,
                "may_claim_complete": false
            }),
        );
        assert_eq!(result.verification, FalseGreenVerdict::Accepted);
        assert_eq!(result.verification_status, "accepted");
        assert_eq!(result.completion_authority, CompletionAuthority::default());
        assert!(!result.permits_completion());
    }

    #[test]
    fn authority_matrix_requires_both_flags_and_accepted_verification() {
        for authority_ready in [false, true] {
            for may_claim_complete in [false, true] {
                let (result, _) = verify_shape(
                    json!({"task_id": "task_1", "status": "accepted"}),
                    json!({
                        "task_id": "task_1",
                        "status": "accepted",
                        "authority_ready": authority_ready,
                        "may_claim_complete": may_claim_complete
                    }),
                );
                assert_eq!(
                    result.permits_completion(),
                    authority_ready && may_claim_complete
                );
            }
        }
        let (failed, _) = verify_shape(
            json!({"task_id": "task_1", "status": "failed"}),
            json!({
                "task_id": "task_1",
                "status": "failed",
                "authority_ready": true,
                "may_claim_complete": true
            }),
        );
        assert_eq!(failed.verification, FalseGreenVerdict::Failed);
        assert!(!failed.permits_completion());
    }

    #[test]
    fn only_core_repair_authorization_opens_repair_path_without_double_consumption() {
        let decision = json!({
            "task_id": "task_1",
            "status": "incomplete",
            "repair_authorized": true,
            "repair_cycles_remaining": 1,
            "failures": [{"criterion": "AC-1", "summary": "failed"}]
        });
        let (result, mut verifier) = verify_shape(
            decision.clone(),
            json!({"task_id": "task_1", "status": "incomplete"}),
        );
        assert!(result.repairable);
        let directory = git_fixture();
        let workspace = Workspace::open(directory.path()).expect("workspace");
        assert_eq!(verifier.prepare_repair(&workspace).unwrap(), decision);
        assert!(matches!(
            verifier.prepare_repair(&workspace),
            Err(FalseGreenError::MissingRepairEvidence)
        ));
    }

    #[test]
    fn local_status_and_remaining_budget_cannot_infer_repair_authority() {
        let (result, mut verifier) = verify_shape(
            json!({
                "task_id": "task_1",
                "status": "incomplete",
                "repair_cycles_remaining": 2
            }),
            json!({"task_id": "task_1", "status": "incomplete"}),
        );
        assert!(!result.repairable);
        let directory = git_fixture();
        let workspace = Workspace::open(directory.path()).expect("workspace");
        assert!(matches!(
            verifier.prepare_repair(&workspace),
            Err(FalseGreenError::MissingRepairEvidence)
        ));
    }

    #[test]
    fn unknown_status_is_invalid_even_with_authority_flags() {
        let (result, _) = verify_shape(
            json!({"task_id": "task_1", "status": "model_says_done"}),
            json!({
                "task_id": "task_1",
                "authority_ready": true,
                "may_claim_complete": true
            }),
        );
        assert_eq!(result.verification, FalseGreenVerdict::Invalid);
        assert!(!result.permits_completion());
    }
}