testty 0.11.1

//! Scenario step definitions for TUI test automation.
//!
//! Each [`Step`] represents a single action in a test scenario, such as
//! typing text, pressing a key, waiting for output, or capturing a frame.
//! Steps are designed to be compiled into both PTY executor actions and
//! VHS tape commands from a single authored scenario.

use std::fmt;
use std::sync::Arc;
use std::time::Duration;

use crate::assertion::MatchResult;
use crate::frame::TerminalFrame;

/// Shared boxed predicate evaluated against a [`TerminalFrame`].
///
/// Used as the payload of [`Step::Eventually`] so the same predicate value
/// can be cloned with the enclosing [`Step`] without re-allocating the
/// underlying closure.
pub type FramePredicate = Arc<dyn Fn(&TerminalFrame) -> MatchResult + Send + Sync>;

/// A single action in a test scenario.
///
/// Steps describe user interactions and wait conditions in a
/// platform-neutral way. The PTY executor runs them directly against
/// the terminal, while the VHS compiler translates them into tape syntax.
#[derive(Clone)]
pub enum Step {
    /// Type text into the terminal.
    WriteText(String),

    /// Press a named key (e.g., `"Enter"`, `"Tab"`, `"Escape"`, `"Up"`).
    PressKey(String),

    /// Sleep for a fixed duration.
    Sleep(Duration),

    /// Wait until the specified text appears in the terminal output.
    WaitForText {
        /// The text to search for.
        needle: String,
        /// Maximum time to wait in milliseconds.
        timeout_ms: u32,
    },

    /// Wait until the terminal frame stops changing.
    WaitForStableFrame {
        /// Duration of stability required in milliseconds.
        stable_ms: u32,
        /// Maximum time to wait in milliseconds.
        timeout_ms: u32,
    },

    /// Poll a frame predicate until it returns `Ok(())` or the timeout elapses.
    ///
    /// The PTY executor re-reads the live terminal frame on every `poll`
    /// tick and runs `predicate` against it. The first `Ok(())` result
    /// returns immediately, while a timeout surfaces the last
    /// [`crate::assertion::AssertionFailure`] the predicate produced so the
    /// proof report keeps its structured failure context. VHS recordings
    /// have no equivalent semantics and skip this step.
    Eventually {
        /// Maximum time to spend polling before surfacing the last failure.
        timeout: Duration,
        /// Interval between predicate evaluations.
        poll: Duration,
        /// Frame predicate evaluated on every tick.
        predicate: FramePredicate,
    },

    /// Capture the current terminal state for assertions.
    Capture,

    /// Capture the current terminal state with a label and description.
    ///
    /// Labeled captures are collected into a
    /// [`crate::proof::report::ProofReport`] during execution, enabling
    /// annotated proof output that documents each step of a test journey.
    CaptureLabeled {
        /// Short identifier for this capture (used in headings and file names).
        label: String,
        /// Human-readable description of what this capture documents.
        description: String,
    },

    /// Viewing pause for GIF recordings — no-op in PTY execution.
    ///
    /// Compiles to a `Sleep` in VHS tape output so human viewers can absorb
    /// the current frame before the next action. The PTY executor skips
    /// this step entirely, keeping assertion-only test runs fast.
    ViewingPause(Duration),
}

impl Step {
    /// Create a step that types the given text.
    pub fn write_text(text: impl Into<String>) -> Self {
        Self::WriteText(text.into())
    }

    /// Create a step that presses a named key.
    pub fn press_key(key: impl Into<String>) -> Self {
        Self::PressKey(key.into())
    }

    /// Create a step that sleeps for the given duration.
    pub fn sleep(duration: Duration) -> Self {
        Self::Sleep(duration)
    }

    /// Create a step that sleeps for the given number of milliseconds.
    pub fn sleep_ms(ms: u64) -> Self {
        Self::Sleep(Duration::from_millis(ms))
    }

    /// Create a step that waits for text to appear.
    pub fn wait_for_text(needle: impl Into<String>, timeout_ms: u32) -> Self {
        Self::WaitForText {
            needle: needle.into(),
            timeout_ms,
        }
    }

    /// Create a step that waits for the frame to stabilize.
    pub fn wait_for_stable_frame(stable_ms: u32, timeout_ms: u32) -> Self {
        Self::WaitForStableFrame {
            stable_ms,
            timeout_ms,
        }
    }

    /// Create a step that polls `predicate` against the live frame until it
    /// returns `Ok(())` or `timeout` elapses.
    ///
    /// The predicate is wrapped in an [`Arc`] so the resulting [`Step`] can
    /// be cloned across scenario reuse without re-allocating the closure.
    /// On timeout the executor surfaces the last
    /// [`crate::assertion::AssertionFailure`] the predicate produced so the
    /// proof report can render the structured context.
    pub fn eventually<F>(timeout: Duration, poll: Duration, predicate: F) -> Self
    where
        F: Fn(&TerminalFrame) -> MatchResult + Send + Sync + 'static,
    {
        Self::Eventually {
            timeout,
            poll,
            predicate: Arc::new(predicate),
        }
    }

    /// Create a capture step.
    pub fn capture() -> Self {
        Self::Capture
    }

    /// Create a labeled capture step.
    ///
    /// The `label` is a short identifier used in headings, and the
    /// `description` explains what this capture documents.
    pub fn capture_labeled(label: impl Into<String>, description: impl Into<String>) -> Self {
        Self::CaptureLabeled {
            label: label.into(),
            description: description.into(),
        }
    }

    /// Create a viewing pause step with the given duration.
    ///
    /// The pause only affects VHS tape output. PTY execution skips it.
    pub fn viewing_pause(duration: Duration) -> Self {
        Self::ViewingPause(duration)
    }

    /// Create a viewing pause step from a millisecond count.
    ///
    /// The pause only affects VHS tape output. PTY execution skips it.
    pub fn viewing_pause_ms(ms: u64) -> Self {
        Self::ViewingPause(Duration::from_millis(ms))
    }
}

/// Manual `Debug` implementation that hides the [`Step::Eventually`]
/// predicate body so the enclosing `#[derive(Clone)]` keeps compiling
/// even though `dyn Fn` does not implement [`fmt::Debug`].
impl fmt::Debug for Step {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::WriteText(text) => f.debug_tuple("WriteText").field(text).finish(),
            Self::PressKey(key) => f.debug_tuple("PressKey").field(key).finish(),
            Self::Sleep(duration) => f.debug_tuple("Sleep").field(duration).finish(),
            Self::WaitForText { needle, timeout_ms } => f
                .debug_struct("WaitForText")
                .field("needle", needle)
                .field("timeout_ms", timeout_ms)
                .finish(),
            Self::WaitForStableFrame {
                stable_ms,
                timeout_ms,
            } => f
                .debug_struct("WaitForStableFrame")
                .field("stable_ms", stable_ms)
                .field("timeout_ms", timeout_ms)
                .finish(),
            Self::Eventually { timeout, poll, .. } => f
                .debug_struct("Eventually")
                .field("timeout", timeout)
                .field("poll", poll)
                .field("predicate", &"<frame predicate>")
                .finish(),
            Self::Capture => f.debug_tuple("Capture").finish(),
            Self::CaptureLabeled { label, description } => f
                .debug_struct("CaptureLabeled")
                .field("label", label)
                .field("description", description)
                .finish(),
            Self::ViewingPause(duration) => f.debug_tuple("ViewingPause").field(duration).finish(),
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn write_text_stores_content() {
        // Arrange / Act
        let step = Step::write_text("hello");

        // Assert
        let Step::WriteText(text) = step else {
            unreachable!("Expected WriteText variant");
        };
        assert_eq!(text, "hello");
    }

    #[test]
    fn sleep_ms_converts_to_duration() {
        // Arrange / Act
        let step = Step::sleep_ms(500);

        // Assert
        let Step::Sleep(duration) = step else {
            unreachable!("Expected Sleep variant");
        };
        assert_eq!(duration, Duration::from_millis(500));
    }

    #[test]
    fn capture_labeled_stores_label_and_description() {
        // Arrange / Act
        let step = Step::capture_labeled("startup", "App launched");

        // Assert
        let Step::CaptureLabeled { label, description } = step else {
            unreachable!("Expected CaptureLabeled variant");
        };
        assert_eq!(label, "startup");
        assert_eq!(description, "App launched");
    }

    #[test]
    fn wait_for_text_stores_needle_and_timeout() {
        // Arrange / Act
        let step = Step::wait_for_text("Loading", 5000);

        // Assert
        let Step::WaitForText { needle, timeout_ms } = step else {
            unreachable!("Expected WaitForText variant");
        };
        assert_eq!(needle, "Loading");
        assert_eq!(timeout_ms, 5000);
    }

    #[test]
    fn viewing_pause_stores_duration() {
        // Arrange / Act
        let step = Step::viewing_pause(Duration::from_secs(2));

        // Assert
        let Step::ViewingPause(duration) = step else {
            unreachable!("Expected ViewingPause variant");
        };
        assert_eq!(duration, Duration::from_secs(2));
    }

    #[test]
    fn viewing_pause_ms_converts_to_duration() {
        // Arrange / Act
        let step = Step::viewing_pause_ms(1500);

        // Assert
        let Step::ViewingPause(duration) = step else {
            unreachable!("Expected ViewingPause variant");
        };
        assert_eq!(duration, Duration::from_millis(1500));
    }

    /// Verifies `Step::eventually` stores the timeout, poll, and a callable
    /// predicate, and that destructuring through the documented field shape
    /// keeps compiling against the public variant layout.
    #[test]
    fn eventually_stores_timeout_poll_and_callable_predicate() {
        // Arrange / Act
        let step = Step::eventually(
            Duration::from_secs(5),
            Duration::from_millis(100),
            |frame: &TerminalFrame| {
                if frame.all_text().contains("Ready") {
                    Ok(())
                } else {
                    Err(Box::new(crate::assertion::AssertionFailure {
                        message: "missing Ready".to_string(),
                        expected: crate::assertion::Expected::TextInRegion {
                            needle: "Ready".to_string(),
                        },
                        region: None,
                        matched_spans: Vec::new(),
                        frame_excerpt: String::new(),
                    }))
                }
            },
        );

        // Assert
        let Step::Eventually {
            timeout,
            poll,
            predicate,
        } = step
        else {
            unreachable!("Expected Eventually variant");
        };
        assert_eq!(timeout, Duration::from_secs(5));
        assert_eq!(poll, Duration::from_millis(100));

        let ready_frame = TerminalFrame::new(80, 24, b"Ready");
        let blank_frame = TerminalFrame::new(80, 24, b"");
        assert!(predicate(&ready_frame).is_ok());
        assert!(predicate(&blank_frame).is_err());
    }

    /// Verifies the manual `Debug` impl for [`Step::Eventually`] redacts the
    /// predicate body so the derived `Clone` keeps compiling and consumers
    /// see a stable placeholder rather than a closure pointer.
    #[test]
    fn eventually_debug_redacts_predicate_body() {
        // Arrange
        let step = Step::eventually(
            Duration::from_millis(250),
            Duration::from_millis(25),
            |_| Ok(()),
        );

        // Act
        let rendered = format!("{step:?}");

        // Assert
        assert!(rendered.contains("Eventually"));
        assert!(rendered.contains("frame predicate"));
    }
}