refactor tmuxedit to Agent interface with cursor/claude/config implementations

Replace monolithic AgentConfig struct with an Agent interface backed by
baseAgent defaults and separate implementations for cursor (box-drawing
extraction, bulk backspace clearing) and claude (section-scoped extraction
with continuation lines, vim clearing). Simple agents (amp, aider) and
user-defined agents use configAgent with baseAgent defaults.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 58 insertions, 0 deletions

diff --git a/internal/tmuxedit/cursor_agent.go b/internal/tmuxedit/cursor_agent.go
new file mode 100644
index 0000000..1346d05
--- /dev/null
+++ b/internal/tmuxedit/cursor_agent.go
@@ -0,0 +1,58 @@
+package tmuxedit
+
+import (
+	"regexp"
+)
+
+// cursorAgent handles Cursor's distinctive box-drawing │ → prompt │ UI.
+// Cursor uses a text field (not vim), so clearing is done with End + bulk
+// backspace. Multi-line prompts are entered with Shift-Enter within the box.
+type cursorAgent struct{ baseAgent }
+
+// newCursorAgent returns a cursorAgent with the default configuration.
+// Detect by the box structure or "/ commands" footer. Checked first because
+// cursor panes often show model names like "Claude 4.5 Sonnet".
+func newCursorAgent() *cursorAgent {
+	return &cursorAgent{baseAgent{
+		name:          "cursor",
+		displayName:   "Cursor",
+		detectPattern: `(│\s*→|/ commands · @ files)`,
+		promptPat:     `(?m)│\s*→?\s*(.+?)\s*│\s*$`,
+		stripPatterns: []string{"INSERT", "Add a follow-up", "ctrl+c to stop"},
+		clearFirst:    true,
+		clearKeys:     "End BSpace*200",
+		newlineKeys:   "S-Enter",
+		submitKeys:    "Enter",
+	}}
+}
+
+// ExtractPrompt extracts the prompt text from the last contiguous │...│ block
+// in the pane. This avoids picking up earlier command-review or dialog boxes
+// that also use box-drawing characters.
+func (c *cursorAgent) ExtractPrompt(paneContent string) string {
+	if c.promptPat == "" {
+		return ""
+	}
+	re, err := regexp.Compile(c.promptPat)
+	if err != nil {
+		return ""
+	}
+	allMatches := matchPromptLines(re, paneContent)
+	if len(allMatches) == 0 {
+		return ""
+	}
+	return joinLastContiguousBlock(allMatches, c.stripPatterns)
+}
+
+// ClearInput sends End + 200 backspaces to clear Cursor's text field.
+// Cursor's input is a standard text field, not vim.
+func (c *cursorAgent) ClearInput(paneID string) error {
+	if !c.clearFirst || c.clearKeys == "" {
+		return nil
+	}
+	if err := sendClearSequence(paneID, c.clearKeys); err != nil {
+		return err
+	}
+	sleepAfterClear()
+	return nil
+}