// file: crates/ksp-job-api/unit_tests/lifecycle.rs
// version: 2

fn new_lifecycle() -> std::option::Option<crate::JobLifecycle> {
    let id = match crate::JobId::new("job-001") {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(_) => return std::option::Option::None,
    };
    let kind = match crate::JobKindCode::new("backfill_raw") {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(_) => return std::option::Option::None,
    };
    return std::option::Option::Some(crate::JobLifecycle::new(id, kind));
}

#[test]
fn pre_002_lifecycle_accepts_every_planned_terminal_path() {
    for completion in [crate::JobCompletion::Complete, crate::JobCompletion::Partial] {
        let lifecycle = new_lifecycle();
        assert!(lifecycle.is_some());
        let mut lifecycle = match lifecycle {
            std::option::Option::Some(value) => value,
            std::option::Option::None => continue,
        };
        assert!(lifecycle.start().is_ok());
        assert!(lifecycle.complete(completion).is_ok());
        assert_eq!(lifecycle.state(), crate::JobState::Completed(completion));
        assert!(lifecycle.state().is_terminal());
        assert_eq!(lifecycle.state().completion(), std::option::Option::Some(completion));
    }
    let lifecycle = new_lifecycle();
    assert!(lifecycle.is_some());
    let mut lifecycle = match lifecycle {
        std::option::Option::Some(value) => value,
        std::option::Option::None => return,
    };
    assert!(lifecycle.start().is_ok());
    assert!(lifecycle.fail().is_ok());
    assert_eq!(lifecycle.state(), crate::JobState::Failed);
    let lifecycle = new_lifecycle();
    assert!(lifecycle.is_some());
    let mut lifecycle = match lifecycle {
        std::option::Option::Some(value) => value,
        std::option::Option::None => return,
    };
    assert!(lifecycle.mark_cancelled().is_ok());
    assert_eq!(lifecycle.state(), crate::JobState::Cancelled);
    return;
}

#[test]
fn pre_002_cancelling_allows_cancel_complete_or_fail() {
    for terminal in [crate::JobState::Cancelled, crate::JobState::Completed(crate::JobCompletion::Complete), crate::JobState::Failed] {
        let lifecycle = new_lifecycle();
        assert!(lifecycle.is_some());
        let mut lifecycle = match lifecycle {
            std::option::Option::Some(value) => value,
            std::option::Option::None => continue,
        };
        assert!(lifecycle.start().is_ok());
        assert!(lifecycle.mark_cancelling().is_ok());
        let result = match terminal {
            crate::JobState::Cancelled => lifecycle.mark_cancelled(),
            crate::JobState::Completed(completion) => lifecycle.complete(completion),
            crate::JobState::Failed => lifecycle.fail(),
            _ => return,
        };
        assert!(result.is_ok());
        assert_eq!(lifecycle.state(), terminal);
    }
    return;
}

#[test]
fn pre_002_invalid_transition_preserves_source_state_and_reports_safe_context() {
    let lifecycle = new_lifecycle();
    assert!(lifecycle.is_some());
    let mut lifecycle = match lifecycle {
        std::option::Option::Some(value) => value,
        std::option::Option::None => return,
    };
    let rejected = lifecycle.complete(crate::JobCompletion::Complete);
    assert!(rejected.is_err());
    assert_eq!(lifecycle.state(), crate::JobState::Created);
    let error = match rejected {
        std::result::Result::Err(value) => value,
        std::result::Result::Ok(_) => return,
    };
    assert_eq!(error.code(), crate::ERROR_CODE_JOB_TRANSITION_INVALID);
    assert_eq!(error.context().len(), 2);
    assert_eq!(error.context()[0].key(), "source_state");
    assert_eq!(error.context()[0].value(), "created");
    assert_eq!(error.context()[1].key(), "target_state");
    assert_eq!(error.context()[1].value(), "completed");
    return;
}

#[test]
fn pre_002_every_terminal_state_rejects_later_mutation() {
    let terminals = [crate::JobState::Completed(crate::JobCompletion::Complete), crate::JobState::Cancelled, crate::JobState::Failed];
    for terminal in terminals {
        let lifecycle = new_lifecycle();
        assert!(lifecycle.is_some());
        let mut lifecycle = match lifecycle {
            std::option::Option::Some(value) => value,
            std::option::Option::None => continue,
        };
        if terminal == crate::JobState::Cancelled {
            assert!(lifecycle.mark_cancelled().is_ok());
        } else {
            assert!(lifecycle.start().is_ok());
            let terminal_result = match terminal {
                crate::JobState::Completed(completion) => lifecycle.complete(completion),
                crate::JobState::Failed => lifecycle.fail(),
                _ => return,
            };
            assert!(terminal_result.is_ok());
        }
        let rejected = lifecycle.start();
        assert!(rejected.is_err());
        assert_eq!(lifecycle.state(), terminal);
    }
    return;
}

#[test]
fn pre_002_transition_matrix_is_exact() {
    let states = [
        crate::JobState::Created,
        crate::JobState::Running,
        crate::JobState::Cancelling,
        crate::JobState::Completed(crate::JobCompletion::Complete),
        crate::JobState::Cancelled,
        crate::JobState::Failed,
    ];
    for source in states {
        for target in states {
            let expected = matches!(
                (source, target),
                (crate::JobState::Created, crate::JobState::Running)
                    | (crate::JobState::Created, crate::JobState::Cancelled)
                    | (crate::JobState::Running, crate::JobState::Cancelling)
                    | (crate::JobState::Running, crate::JobState::Completed(_))
                    | (crate::JobState::Running, crate::JobState::Failed)
                    | (crate::JobState::Cancelling, crate::JobState::Completed(_))
                    | (crate::JobState::Cancelling, crate::JobState::Cancelled)
                    | (crate::JobState::Cancelling, crate::JobState::Failed)
            );
            assert_eq!(super::allowed_transition(source, target), expected, "unexpected transition matrix result for {source:?} -> {target:?}");
        }
    }
    return;
}