feat: make agent automation a first-class cli primitive

1 files changed, 52 insertions, 0 deletions

diff --git a/src/app/api_helpers.rs b/src/app/api_helpers.rs
index c7dc39d2..6c393dac 100644
--- a/src/app/api_helpers.rs
+++ b/src/app/api_helpers.rs
@@ -101,6 +101,58 @@ pub(super) fn pane_agent_status(
     }
 }
 
+pub(super) fn read_terminal_snapshot(
+    terminal: &crate::terminal::TerminalRuntime,
+    source: crate::api::schema::ReadSource,
+    format: crate::api::schema::ReadFormat,
+    lines: Option<u32>,
+) -> String {
+    use crate::api::schema::{ReadFormat, ReadSource};
+
+    let requested_lines = lines.unwrap_or(80).min(1000) as usize;
+    let text = match (format, source) {
+        (ReadFormat::Text, ReadSource::Visible) => terminal.visible_text(),
+        (ReadFormat::Text, ReadSource::Recent) => terminal.recent_text(requested_lines),
+        (ReadFormat::Text, ReadSource::RecentUnwrapped) => {
+            terminal.recent_unwrapped_text(requested_lines)
+        }
+        (ReadFormat::Text, ReadSource::Detection) => terminal.detection_text(),
+        (ReadFormat::Ansi, ReadSource::Visible) => terminal.visible_ansi(),
+        (ReadFormat::Ansi, ReadSource::Recent) => terminal.recent_ansi(requested_lines),
+        (ReadFormat::Ansi, ReadSource::RecentUnwrapped) => {
+            terminal.recent_unwrapped_ansi(requested_lines)
+        }
+        (ReadFormat::Ansi, ReadSource::Detection) => terminal.detection_text(),
+    };
+
+    if lines.is_some() && matches!(source, ReadSource::Visible | ReadSource::Detection) {
+        last_lines(&text, requested_lines)
+    } else {
+        text
+    }
+}
+
+fn last_lines(text: &str, count: usize) -> String {
+    if text.is_empty() || count == 0 {
+        return String::new();
+    }
+    let lines: Vec<_> = text.split_inclusive('\n').collect();
+    lines[lines.len().saturating_sub(count)..].concat()
+}
+
+#[cfg(test)]
+mod read_snapshot_tests {
+    use super::last_lines;
+
+    #[test]
+    fn last_lines_preserves_real_line_endings_and_unicode() {
+        assert_eq!(last_lines("one\ntwø\n三\n", 2), "twø\n三\n");
+        assert_eq!(last_lines("one\ntwo\nthree", 1), "three");
+        assert_eq!(last_lines("one\ntwo", 0), "");
+        assert_eq!(last_lines("", 2), "");
+    }
+}
+
 pub(super) fn normalize_reported_agent_label(agent: &str) -> Option<String> {
     let trimmed = agent.trim();
     if trimmed.is_empty() {