Add compact language assistance rails

src/leader.zig

@@ -13,6 +13,7 @@ test {
 pub const Feature = enum {
     search,
     panel_close,
+    lsp,
 };
 
 pub const Action = union(enum) {
@@ -24,6 +25,9 @@ pub const Action = union(enum) {
     file_picker,
     search_file,
     search_project,
+    hover,
+    signature,
+    expand_hover,
     repeat_rail,
     restore_last,
     not_built: Feature,
@@ -41,6 +45,7 @@ const Mode = enum {
     rail,
     symbol_rail,
     search_rail,
+    language_rail,
     open_prompt,
 };
 
@@ -65,6 +70,7 @@ pub const Leader = struct {
             .rail => return self.handleRail(event),
             .symbol_rail => return self.handleSymbolRail(event),
             .search_rail => return self.handleSearchRail(event),
+            .language_rail => return self.handleLanguageRail(event),
             .open_prompt => return self.handleOpenPrompt(event),
         }
     }
@@ -76,6 +82,7 @@ pub const Leader = struct {
             .rail => "leader: w save  q quit  o open  p symbols  s search  r repeat  x close",
             .symbol_rail => symbol_mod.rail_status,
             .search_rail => "search: f current file  p project  s symbols",
+            .language_rail => "language: h hover  s signature  o open hover",
             .open_prompt => "open: type path, Enter opens, Esc cancels",
         };
     }
@@ -120,6 +127,10 @@ pub const Leader = struct {
                     self.mode = .search_rail;
                     return .none;
                 }
+                if (std.mem.eql(u8, text, "l")) {
+                    self.mode = .language_rail;
+                    return .none;
+                }
                 if (std.mem.eql(u8, text, "q")) {
                     self.mode = .idle;
                     return .quit;
@@ -174,6 +185,37 @@ pub const Leader = struct {
         }
     }
 
+    fn handleLanguageRail(self: *Leader, event: input.Event) Action {
+        self.message = null;
+        switch (event) {
+            .text => |text| {
+                self.mode = .idle;
+                if (std.mem.eql(u8, text, "h")) return .hover;
+                if (std.mem.eql(u8, text, "s")) return .signature;
+                if (std.mem.eql(u8, text, "o")) return .expand_hover;
+                self.message = "language action is not built in this profile yet";
+                return .{ .not_built = .lsp };
+            },
+            .key => |key| switch (key) {
+                .escape, .backspace => {
+                    self.mode = .idle;
+                    self.message = "language cancelled";
+                    return .none;
+                },
+                else => {
+                    self.mode = .idle;
+                    self.message = "unknown language key";
+                    return .none;
+                },
+            },
+            .unknown => {
+                self.mode = .idle;
+                self.message = "unknown language key";
+                return .none;
+            },
+        }
+    }
+
     fn handleSearchRail(self: *Leader, event: input.Event) Action {
         self.message = null;
         switch (event) {

src/lsp.zig

@@ -163,6 +163,52 @@ pub fn missingProviderRowAlloc(allocator: std.mem.Allocator, capability: Provide
     return std.fmt.allocPrint(allocator, "provider:missing:{s}", .{@tagName(capability)});
 }
 
+pub fn compactHoverCardAlloc(allocator: std.mem.Allocator, row: []const u8, width: usize) ![]u8 {
+    const provider = providerIdFromRow(row) catch "unknown";
+    const payload = providerPayloadFromRow(row) catch row;
+    const prefix = "lsp:hover:";
+    const body = if (std.mem.startsWith(u8, payload, prefix)) payload[prefix.len..] else payload;
+    const split = std.mem.indexOfScalar(u8, body, '|') orelse body.len;
+    const headline = body[0..split];
+    const docs = if (split < body.len) body[split + 1 ..] else "";
+    const budget = if (width > provider.len + headline.len + 8) width - provider.len - headline.len - 8 else 0;
+    const excerpt_len = @min(docs.len, budget);
+    return std.fmt.allocPrint(allocator, "[{s}] {s}{s}{s}", .{ provider, headline, if (excerpt_len > 0) " — " else "", docs[0..excerpt_len] });
+}
+
+pub fn expandedHoverRowsAlloc(allocator: std.mem.Allocator, row: []const u8, width: usize) ![][]const u8 {
+    const provider = providerIdFromRow(row) catch "unknown";
+    const payload = providerPayloadFromRow(row) catch row;
+    const prefix = "lsp:hover:";
+    const body = if (std.mem.startsWith(u8, payload, prefix)) payload[prefix.len..] else payload;
+    var rows = std.ArrayList([]const u8).empty;
+    errdefer {
+        for (rows.items) |item| allocator.free(item);
+        rows.deinit(allocator);
+    }
+    try rows.append(allocator, try std.fmt.allocPrint(allocator, "hover_provider:{s}", .{provider}));
+    var start: usize = 0;
+    const wrap = @max(width, 8);
+    while (start < body.len) {
+        const end = @min(start + wrap, body.len);
+        const wrapped = try allocator.dupe(u8, body[start..end]);
+        for (wrapped) |*byte| {
+            if (byte.* <= 0x20 or byte.* == '|') byte.* = '_';
+        }
+        try rows.append(allocator, wrapped);
+        start = end;
+    }
+    return rows.toOwnedSlice(allocator);
+}
+
+pub fn compactSignatureCardAlloc(allocator: std.mem.Allocator, row: []const u8) ![]u8 {
+    const provider = providerIdFromRow(row) catch "unknown";
+    const payload = providerPayloadFromRow(row) catch row;
+    const prefix = "lsp:signature:";
+    const body = if (std.mem.startsWith(u8, payload, prefix)) payload[prefix.len..] else payload;
+    return std.fmt.allocPrint(allocator, "[{s}] {s}", .{ provider, body });
+}
+
 pub fn providerPickerRowsAlloc(allocator: std.mem.Allocator, capability: ProviderCapability, providers: []const Provider) ![][]const u8 {
     var rows = std.ArrayList([]const u8).empty;
     errdefer {

src/tui.zig

@@ -136,6 +136,7 @@ pub const Client = struct {
     viewport: Viewport,
     saved_bytes: ?[]u8 = null,
     message: ?[]const u8 = null,
+    owned_message: ?[]u8 = null,
     quit: bool = false,
     mode: EditorMode = .normal,
     prefix: PrefixRail = .none,
@@ -149,6 +150,8 @@ pub const Client = struct {
     project_search_prompt_active: bool = false,
     project_search_prompt: std.ArrayList(u8) = .empty,
     panel_context: PanelContext = .none,
+    hover_rows: std.ArrayList([]u8) = .empty,
+    signature_rows: std.ArrayList([]u8) = .empty,
     undo_stack: std.ArrayList(EditSnapshot) = .empty,
     redo_stack: std.ArrayList(EditSnapshot) = .empty,
     yank_bytes: ?[]u8 = null,
@@ -171,11 +174,14 @@ pub const Client = struct {
 
     pub fn deinit(self: *Client) void {
         if (self.saved_bytes) |bytes| self.allocator.free(bytes);
+        if (self.owned_message) |bytes| self.allocator.free(bytes);
         if (self.yank_bytes) |bytes| self.allocator.free(bytes);
         self.search_prompt.deinit(self.allocator);
         self.project_search_prompt.deinit(self.allocator);
         self.allocator.free(self.search_query);
         self.search_matches.deinit(self.allocator);
+        self.freeOwnedClientRows(&self.hover_rows);
+        self.freeOwnedClientRows(&self.signature_rows);
         self.freeSnapshotStack(&self.undo_stack);
         self.freeSnapshotStack(&self.redo_stack);
         self.repo.deinit();
@@ -195,6 +201,8 @@ pub const Client = struct {
         if (std.mem.startsWith(u8, line, "type ")) return self.handleInput(line[5..]);
         if (std.mem.startsWith(u8, line, "repo_gitignore ")) return self.repo.addIgnorePattern(line[15..]);
         if (std.mem.startsWith(u8, line, "repo_file ")) return self.addRepoFile(line[10..]);
+        if (std.mem.startsWith(u8, line, "lsp_hover_fixture ")) return self.addHoverFixture(line[18..]);
+        if (std.mem.startsWith(u8, line, "lsp_signature_fixture ")) return self.addSignatureFixture(line[22..]);
         if (std.mem.eql(u8, line, "file_picker")) return self.openRepoList("files", false, false);
         if (std.mem.eql(u8, line, "file_picker all")) return self.openRepoList("files", false, true);
         if (std.mem.eql(u8, line, "file_tree")) return self.openRepoList("tree", true, false);
@@ -432,6 +440,14 @@ pub const Client = struct {
     }
 
     pub fn setStatusMessage(self: *Client, message: []const u8) void {
+        if (self.owned_message) |old| self.allocator.free(old);
+        self.owned_message = null;
+        self.message = message;
+    }
+
+    fn setOwnedStatusMessage(self: *Client, message: []u8) void {
+        if (self.owned_message) |old| self.allocator.free(old);
+        self.owned_message = message;
         self.message = message;
     }
 
@@ -463,6 +479,12 @@ pub const Client = struct {
         };
     }
 
+    fn freeOwnedClientRows(self: *Client, rows: *std.ArrayList([]u8)) void {
+        for (rows.items) |row| self.allocator.free(row);
+        rows.deinit(self.allocator);
+        rows.* = .empty;
+    }
+
     pub fn addRepoFileContent(self: *Client, path: []const u8, file_bytes: []const u8) !void {
         if (file_bytes.len > diagnostics_mod.max_file_bytes) {
             self.message = "diagnostic:file_too_large";
@@ -475,6 +497,23 @@ pub const Client = struct {
         self.message = null;
     }
 
+    fn addHoverFixture(self: *Client, payload: []const u8) !void {
+        var parts = std.mem.splitScalar(u8, payload, '|');
+        const provider = parts.next() orelse "fixture";
+        const headline = parts.next() orelse "hover";
+        const docs = parts.rest();
+        const row = try std.fmt.allocPrint(self.allocator, "provider:{s}:lsp:hover:{s}|{s}", .{ provider, headline, docs });
+        try self.hover_rows.append(self.allocator, row);
+    }
+
+    fn addSignatureFixture(self: *Client, payload: []const u8) !void {
+        var parts = std.mem.splitScalar(u8, payload, '|');
+        const provider = parts.next() orelse "fixture";
+        const signature = parts.rest();
+        const row = try std.fmt.allocPrint(self.allocator, "provider:{s}:lsp:signature:{s}", .{ provider, signature });
+        try self.signature_rows.append(self.allocator, row);
+    }
+
     fn addRepoFile(self: *Client, payload: []const u8) !void {
         const separator = std.mem.indexOfScalar(u8, payload, '=') orelse {
             self.message = "diagnostic:unsupported_file:invalid_repo_file_payload";
@@ -943,7 +982,7 @@ pub const Client = struct {
             .match => self.applyMatchRail(event) catch |err| {
                 self.message = @errorName(err);
             },
-            .go => self.applyKnownRailOrMessage(event, "go rail ready"),
+            .go => try self.applyGoRail(event),
             .repeat => self.applyKnownRailOrMessage(event, "repeat rail ready"),
             .delete => try self.applyDeleteRail(event),
             .change => try self.applyChangeRail(event),
@@ -1019,16 +1058,8 @@ pub const Client = struct {
             self.message = "empty list";
             return;
         }
-        var joined = std.ArrayList(u8).empty;
-        defer joined.deinit(self.allocator);
-        try joined.appendSlice(self.allocator, "list_open ");
-        try joined.appendSlice(self.allocator, title);
-        try joined.append(self.allocator, ' ');
-        for (rows, 0..) |row, i| {
-            if (i != 0) try joined.append(self.allocator, '|');
-            try joined.appendSlice(self.allocator, row);
-        }
-        try self.applyProtocol(joined.items);
+        try self.session.openListPanel(title, rows);
+        self.message = null;
         self.panel_context = context;
     }
 
@@ -1114,6 +1145,37 @@ pub const Client = struct {
         self.panel_context = .project_search;
     }
 
+    fn showCompactHover(self: *Client) !void {
+        if (self.hover_rows.items.len == 0) {
+            self.message = "NoProvider:hover";
+            return;
+        }
+        const card = try lsp_mod.compactHoverCardAlloc(self.allocator, self.hover_rows.items[0], self.viewport.width);
+        self.setOwnedStatusMessage(card);
+    }
+
+    fn showCompactSignature(self: *Client) !void {
+        if (self.signature_rows.items.len == 0) {
+            self.message = "NoProvider:signature";
+            return;
+        }
+        const card = try lsp_mod.compactSignatureCardAlloc(self.allocator, self.signature_rows.items[0]);
+        self.setOwnedStatusMessage(card);
+    }
+
+    fn openExpandedHover(self: *Client) !void {
+        if (self.hover_rows.items.len == 0) {
+            self.message = "NoProvider:hover";
+            return;
+        }
+        const rows = try lsp_mod.expandedHoverRowsAlloc(self.allocator, self.hover_rows.items[0], self.viewport.width);
+        defer {
+            for (rows) |row| self.allocator.free(row);
+            self.allocator.free(rows);
+        }
+        try self.openListRows("hover", rows, .none);
+    }
+
     fn openSearchPrompt(self: *Client) void {
         self.search_prompt_active = true;
         self.search_prompt.clearRetainingCapacity();
@@ -1191,6 +1253,52 @@ pub const Client = struct {
         try self.gotoSearchMatch();
     }
 
+    fn applyGoRail(self: *Client, event: input.Event) !void {
+        const text = eventText(event) orelse return self.unknownPrefixOrInput("normal");
+        if (std.mem.eql(u8, text, "a")) return self.moveParameter(.next);
+        if (std.mem.eql(u8, text, "A")) return self.moveParameter(.previous);
+        self.applyKnownRailOrMessage(event, "go rail ready");
+    }
+
+    const ParameterDirection = enum { next, previous };
+
+    fn moveParameter(self: *Client, direction: ParameterDirection) !void {
+        const snap = try self.session.snapshot();
+        const pair = self.matchRange('(', false) catch {
+            self.message = "NoParameterContext";
+            return;
+        };
+        var target: ?usize = null;
+        switch (direction) {
+            .next => {
+                var at = snap.cursor_byte;
+                while (at < pair.end) : (at += 1) {
+                    if (snap.bytes[at] == ',') {
+                        target = at + 1;
+                        break;
+                    }
+                }
+            },
+            .previous => {
+                var at = @min(snap.cursor_byte, pair.end);
+                while (at > pair.start) {
+                    at -= 1;
+                    if (snap.bytes[at] == ',') {
+                        var prev = at;
+                        while (prev > pair.start and snap.bytes[prev - 1] != ',') prev -= 1;
+                        target = prev;
+                        break;
+                    }
+                }
+            },
+        }
+        if (target) |byte| {
+            var trimmed = byte;
+            while (trimmed < pair.end and std.ascii.isWhitespace(snap.bytes[trimmed])) trimmed += 1;
+            try self.session.moveToByte(trimmed);
+        } else self.message = "NoParameterTarget";
+    }
+
     fn applyMatchRail(self: *Client, event: input.Event) !void {
         const text = eventText(event) orelse return self.unknownPrefixOrInput("normal");
         if (std.mem.eql(u8, text, "m")) return self.jumpToMatch(null);
@@ -1564,6 +1672,9 @@ pub const Client = struct {
             .file_picker => try self.openFilePickerPanel(),
             .search_file => self.openSearchPrompt(),
             .search_project => self.openProjectSearchPrompt(),
+            .hover => try self.showCompactHover(),
+            .signature => try self.showCompactSignature(),
+            .expand_hover => try self.openExpandedHover(),
             .repeat_rail => self.openPrefix(.repeat),
             .restore_last => self.restoreLastRail(),
             .not_built => {},
@@ -3539,3 +3650,73 @@ test "adversarial: file and project panels handle ignored empty missing and clos
     defer std.testing.allocator.free(no_match_frame);
     try std.testing.expect(std.mem.indexOf(u8, no_match_frame, "no project matches") != null);
 }
+
+test "regular: language rail shows compact hover signature and expandable hover" {
+    var client = try Client.init(std.testing.allocator, .{ .width = 48, .height = 8 });
+    defer client.deinit();
+    try client.handleTraceLine("lsp_hover_fixture zls|add(lhs, rhs)|Very long documentation that should be compact first and expanded only on request.");
+    try client.handleTraceLine("lsp_signature_fixture zls|add(lhs: i32, rhs: i32) active=rhs");
+
+    try client.handleInput(" ");
+    try client.handleInput("l");
+    try client.handleInput("h");
+    const hover_frame = try client.render(std.testing.allocator);
+    defer std.testing.allocator.free(hover_frame);
+    try std.testing.expect(std.mem.indexOf(u8, hover_frame, "[zls] add(lhs, rhs)") != null);
+    try assertLinesFit(hover_frame, 48);
+
+    try client.handleInput(" ");
+    try client.handleInput("l");
+    try client.handleInput("s");
+    const signature_frame = try client.render(std.testing.allocator);
+    defer std.testing.allocator.free(signature_frame);
+    try std.testing.expect(std.mem.indexOf(u8, signature_frame, "[zls] add(lhs: i32, rhs: i32) active=rhs") != null);
+
+    try client.handleInput(" ");
+    try client.handleInput("l");
+    try client.handleInput("o");
+    const expanded_frame = try client.render(std.testing.allocator);
+    defer std.testing.allocator.free(expanded_frame);
+    try std.testing.expect(std.mem.indexOf(u8, expanded_frame, "hover_provider:zls") != null);
+    try std.testing.expect(std.mem.indexOf(u8, expanded_frame, "Very_long_documentation") != null);
+}
+
+test "adversarial: missing hover and signature providers are visible" {
+    var client = try Client.init(std.testing.allocator, .{ .width = 48, .height = 6 });
+    defer client.deinit();
+
+    try client.handleInput(" ");
+    try client.handleInput("l");
+    try client.handleInput("h");
+    const hover_frame = try client.render(std.testing.allocator);
+    defer std.testing.allocator.free(hover_frame);
+    try std.testing.expect(std.mem.indexOf(u8, hover_frame, "NoProvider:hover") != null);
+
+    try client.handleInput(" ");
+    try client.handleInput("l");
+    try client.handleInput("s");
+    const signature_frame = try client.render(std.testing.allocator);
+    defer std.testing.allocator.free(signature_frame);
+    try std.testing.expect(std.mem.indexOf(u8, signature_frame, "NoProvider:signature") != null);
+}
+
+test "regular: go rail parameter movement uses keymap paths" {
+    var client = try Client.init(std.testing.allocator, .{ .width = 64, .height = 6 });
+    defer client.deinit();
+    try client.handleTraceLine("open call(alpha, beta, gamma)");
+    try client.handleTraceLine("right");
+    try client.handleTraceLine("right");
+    try client.handleTraceLine("right");
+    try client.handleTraceLine("right");
+    try client.handleTraceLine("right");
+
+    try client.handleInput("g");
+    try client.handleInput("a");
+    var snap = try client.session.snapshot();
+    try std.testing.expectEqual(@as(usize, 12), snap.cursor_byte);
+
+    try client.handleInput("g");
+    try client.handleInput("A");
+    snap = try client.session.snapshot();
+    try std.testing.expectEqual(@as(usize, 5), snap.cursor_byte);
+}