From 6b1fd2b9eb17e6f7d3244853bba5366738074dbf Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Wed, 20 Dec 2023 20:50:10 -0800
Subject: [PATCH] terminal: Screen.promptPath

---
 src/terminal/Screen.zig | 123 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 122 insertions(+), 1 deletion(-)

diff --git a/src/terminal/Screen.zig b/src/terminal/Screen.zig
index 2fe5da85c..d7fda6094 100644
--- a/src/terminal/Screen.zig
+++ b/src/terminal/Screen.zig
@@ -1922,6 +1922,39 @@ pub fn selectPrompt(self: *Screen, pt: point.ScreenPoint) ?Selection {
     };
 }
 
+/// Returns the change in x/y that is needed to reach "to" from "from"
+/// within a prompt. If "to" is before or after the prompt bounds then
+/// the result will be bounded to the prompt.
+///
+/// This feature requires shell integration. If shell integration is not
+/// enabled, this will always return zero for both x and y (no path).
+pub fn promptPath(
+    self: *Screen,
+    from: point.ScreenPoint,
+    to: point.ScreenPoint,
+) struct {
+    x: isize,
+    y: isize,
+} {
+    // Get our prompt bounds assuming "from" is at a prompt.
+    const bounds = self.selectPrompt(from) orelse return .{ .x = 0, .y = 0 };
+
+    // Get our actual "to" point clamped to the bounds of the prompt.
+    const to_clamped = if (bounds.contains(to))
+        to
+    else if (to.before(bounds.start))
+        bounds.start
+    else
+        bounds.end;
+
+    // Basic math to calculate our path.
+    const from_x: isize = @intCast(from.x);
+    const from_y: isize = @intCast(from.y);
+    const to_x: isize = @intCast(to_clamped.x);
+    const to_y: isize = @intCast(to_clamped.y);
+    return .{ .x = to_x - from_x, .y = to_y - from_y };
+}
+
 /// Scroll behaviors for the scroll function.
 pub const Scroll = union(enum) {
     /// Scroll to the top of the scroll buffer. The first line of the
@@ -4722,6 +4755,7 @@ test "Screen: selectOutput" {
         try s.testWriteString("output3\n");         // 8
         try s.testWriteString("output3");           // 9
     }
+    // zig fmt: on
 
     var row = s.getRow(.{ .screen = 2 });
     row.setSemanticPrompt(.prompt);
@@ -4794,6 +4828,7 @@ test "Screen: selectPrompt basics" {
         try s.testWriteString("output3\n");         // 8
         try s.testWriteString("output3");           // 9
     }
+    // zig fmt: on
 
     var row = s.getRow(.{ .screen = 2 });
     row.setSemanticPrompt(.prompt);
@@ -4850,6 +4885,7 @@ test "Screen: selectPrompt prompt at start" {
         try s.testWriteString("output2\n");         // 2
         try s.testWriteString("output2\n");         // 3
     }
+    // zig fmt: on
 
     var row = s.getRow(.{ .screen = 0 });
     row.setSemanticPrompt(.prompt);
@@ -4887,6 +4923,7 @@ test "Screen: selectPrompt prompt at end" {
         try s.testWriteString("prompt1\n");         // 2
         try s.testWriteString("input1\n");          // 3
     }
+    // zig fmt: on
 
     var row = s.getRow(.{ .screen = 2 });
     row.setSemanticPrompt(.prompt);
@@ -4909,6 +4946,91 @@ test "Screen: selectPrompt prompt at end" {
     }
 }
 
+test "Screen: promtpPath" {
+    const testing = std.testing;
+    const alloc = testing.allocator;
+
+    var s = try init(alloc, 15, 10, 0);
+    defer s.deinit();
+
+    // zig fmt: off
+    {
+                                                    // line number:
+        try s.testWriteString("output1\n");         // 0
+        try s.testWriteString("output1\n");         // 1
+        try s.testWriteString("prompt2\n");         // 2
+        try s.testWriteString("input2\n");          // 3
+        try s.testWriteString("output2\n");         // 4
+        try s.testWriteString("output2\n");         // 5
+        try s.testWriteString("prompt3$ input3\n"); // 6
+        try s.testWriteString("output3\n");         // 7
+        try s.testWriteString("output3\n");         // 8
+        try s.testWriteString("output3");           // 9
+    }
+    // zig fmt: on
+
+    var row = s.getRow(.{ .screen = 2 });
+    row.setSemanticPrompt(.prompt);
+    row = s.getRow(.{ .screen = 3 });
+    row.setSemanticPrompt(.input);
+    row = s.getRow(.{ .screen = 4 });
+    row.setSemanticPrompt(.command);
+    row = s.getRow(.{ .screen = 6 });
+    row.setSemanticPrompt(.input);
+    row = s.getRow(.{ .screen = 7 });
+    row.setSemanticPrompt(.command);
+
+    // From is not in the prompt
+    {
+        const path = s.promptPath(
+            .{ .x = 0, .y = 1 },
+            .{ .x = 0, .y = 2 },
+        );
+        try testing.expectEqual(@as(isize, 0), path.x);
+        try testing.expectEqual(@as(isize, 0), path.y);
+    }
+
+    // Same line
+    {
+        const path = s.promptPath(
+            .{ .x = 6, .y = 2 },
+            .{ .x = 3, .y = 2 },
+        );
+        try testing.expectEqual(@as(isize, -3), path.x);
+        try testing.expectEqual(@as(isize, 0), path.y);
+    }
+
+    // Different lines
+    {
+        const path = s.promptPath(
+            .{ .x = 6, .y = 2 },
+            .{ .x = 3, .y = 3 },
+        );
+        try testing.expectEqual(@as(isize, -3), path.x);
+        try testing.expectEqual(@as(isize, 1), path.y);
+    }
+
+    // To is out of bounds before
+    {
+        const path = s.promptPath(
+            .{ .x = 6, .y = 2 },
+            .{ .x = 3, .y = 1 },
+        );
+        try testing.expectEqual(@as(isize, -6), path.x);
+        try testing.expectEqual(@as(isize, 0), path.y);
+    }
+
+    // To is out of bounds after
+    {
+        const path = s.promptPath(
+            .{ .x = 6, .y = 2 },
+            .{ .x = 3, .y = 9 },
+        );
+        try testing.expectEqual(@as(isize, 3), path.x);
+        try testing.expectEqual(@as(isize, 1), path.y);
+    }
+}
+
 test "Screen: scrollRegionUp single" {
     const testing = std.testing;
     const alloc = testing.allocator;
@@ -5647,7 +5769,6 @@ test "Screen: selectionString, rectangle, more complex w/breaks" {
     try testing.expectEqualStrings(expected, contents);
 }
 
-
 test "Screen: dirty with getCellPtr" {
     const testing = std.testing;
     const alloc = testing.allocator;