Add persistent configuration storage

CLAUDE.md

@@ -111,6 +111,8 @@ The project is an experimental terminal multiplexer with:
 - **Resizable window** - window can be resized dynamically with automatic terminal and PTY resizing
 - **Terminal switching with panning** - use Cmd+Shift+[ / Cmd+Shift+] to switch between terminals in full-screen mode with smooth horizontal panning animation
 - **Keyboard support** - ESC key collapses expanded sessions back to grid view
+- **Font size adjustment** - Cmd+Plus/Minus to adjust font size (8-32px range, saved automatically)
+- **Persistent configuration** - automatically saves and restores font size, window dimensions, and window position to `~/.config/architect/config.json`
 - **Real-time I/O** - non-blocking PTY reading with live terminal updates
 - **Scrollback in place** - mouse wheel scrolls per-terminal history; typing or new input snaps back to live output and a yellow strip in grid view indicates a scrolled session
 
@@ -132,6 +134,7 @@ Key dependency details:
 - `src/shell.zig` - Shell process spawning and management
 - `src/pty.zig` - PTY (pseudo-terminal) abstractions and utilities
 - `src/font.zig` - Font rendering with SDL_ttf and glyph caching
+- `src/config.zig` - Configuration persistence (font size, window dimensions, and position)
 - `src/c.zig` - C library bindings for SDL3 and SDL_ttf
 - `build.zig` - Zig build configuration with ghostty-vt module and SDL3 dependencies
 - `build.zig.zon` - Package manifest with ghostty path dependency
@@ -189,17 +192,27 @@ The application implements a 3×3 grid with the following components:
 - Mouse clicks detect grid cell selection and trigger expansion
 - ESC key collapses expanded sessions back to grid
 - Cmd+Shift+[ / Cmd+Shift+] switches between terminals in full-screen mode with panning animation
+- Cmd+Plus/Minus adjusts font size (8-32px range)
 - Mouse wheel scrolls per-session history; typing or new output snaps the viewport back to live
 - Keyboard input encoded to ANSI sequences and written to active PTY
 - Non-blocking PTY reads avoid blocking the event loop
-- Window resize events trigger automatic terminal and PTY resizing
+- Window move events update internal position tracking
+- Window resize events trigger automatic config saving and terminal/PTY resizing
+
+**Configuration System:**
+- Settings stored in `~/.config/architect/config.json` as JSON
+- Automatically saves on: window resize, font size change (window position is tracked and saved with these events)
+- Automatically loads on startup with fallback to defaults
+- Configuration includes: `font_size`, `window_width`, `window_height`, `window_x`, `window_y`
+- Config directory created automatically if it doesn't exist
+- Window position uses -1 as sentinel for "no saved position" (allows restoring position at 0,0 or with negative coordinates on multi-monitor setups)
 
 ### Known Limitations
 
 The following features are not yet implemented:
 - **No emoji support**: Unicode emojis may not render correctly
-- **No font selection**: Hardcoded to SF Mono font
-- **No configurability**: Grid size, colors, and keybindings are hardcoded
+- **No font selection**: Hardcoded to SF Mono font (though size is adjustable via Cmd+Plus/Minus)
+- **Limited configurability**: Grid size, colors, and keybindings are hardcoded (font size, window size, and position are configurable)
 - **Limited AI tool compatibility**: Works with Claude and Gemini models, but not with Codex
 
 ## Zig Version

README.md

@@ -59,6 +59,8 @@ See [Setup](#setup) section below for building from source.
   - Type in the focused terminal
 - **Scrollback in Place**: Hover any terminal and use the mouse wheel to scroll history; typing snaps back to live output and a yellow strip in grid view shows when you're scrolled
 - **High-Quality Rendering**: SDL_ttf font rendering with glyph caching, vsynced presentation, and cached grid tiles to reduce redraw work
+- **Persistent Configuration**: Automatically saves and restores font size, window dimensions, and window position
+- **Font Size Adjustment**: Use Cmd+Plus/Minus to adjust font size (saved automatically)
 - **Claude-friendly hooks**: Unix domain socket for notifying Architect when a session is waiting for approval or finished; grid tiles highlight with a fat yellow border
 
 ## Prerequisites
@@ -110,6 +112,32 @@ Run the application:
 zig build run
 ```
 
+## Configuration
+
+Architect automatically saves your preferences to `~/.config/architect/config.json`. The configuration includes:
+
+- **Font size**: Adjusted via Cmd+Plus/Minus shortcuts (range: 8-32px, default: 14px)
+- **Window dimensions**: Automatically saved when you resize the window
+- **Window position**: Saved along with window dimensions when you resize or adjust font size
+
+The configuration file is created automatically on first use and updated whenever settings change. No manual editing required.
+
+**Example configuration:**
+```json
+{
+  "font_size": 16,
+  "window_width": 1920,
+  "window_height": 1080,
+  "window_x": 150,
+  "window_y": 100
+}
+```
+
+To reset to defaults, simply delete the configuration file:
+```bash
+rm ~/.config/architect/config.json
+```
+
 ## Development
 
 Run tests:
@@ -228,6 +256,7 @@ Download the latest release from the [releases page](https://github.com/forketyf
 - `src/shell.zig` - Shell process spawning and management
 - `src/pty.zig` - PTY abstractions and utilities
 - `src/font.zig` - Font rendering with SDL_ttf and glyph caching
+- `src/config.zig` - Configuration persistence (saves font size, window size, and position)
 - `src/c.zig` - C library bindings for SDL3
 - `build.zig` - Zig build configuration with SDL3 dependencies
 - `build.zig.zon` - Zig package dependencies
@@ -273,15 +302,17 @@ The application uses cubic ease-in-out interpolation to smoothly transition betw
 - Keyboard input handling
 - Full-window terminal scaling
 - Dynamic terminal and PTY resizing on window resize
+- Persistent configuration (font size, window size, and position)
+- Font size adjustment via keyboard shortcuts (Cmd+Plus/Minus)
 - Claude Code integration via Unix domain sockets
 - Scrolling back through terminal history (mouse wheel) with a grid indicator when a pane is scrolled
 
 ## Known Limitations
 
 The following features are not yet implemented:
 - **No emoji support**: Unicode emojis may not render correctly
-- **No font selection**: Hardcoded to SF Mono font
-- **No configurability**: Grid size, colors, and keybindings are hardcoded
+- **No font selection**: Hardcoded to SF Mono font (though size is adjustable)
+- **Limited configurability**: Grid size, colors, and keybindings are hardcoded
 - **Limited AI tool compatibility**: Works with Claude and Gemini models, but not with Codex
 
 ## License

src/c.zig

@@ -9,6 +9,7 @@ pub const SDL_Init = c_import.SDL_Init;
 pub const SDL_Quit = c_import.SDL_Quit;
 pub const SDL_CreateWindow = c_import.SDL_CreateWindow;
 pub const SDL_DestroyWindow = c_import.SDL_DestroyWindow;
+pub const SDL_SetWindowPosition = c_import.SDL_SetWindowPosition;
 pub const SDL_CreateRenderer = c_import.SDL_CreateRenderer;
 pub const SDL_DestroyRenderer = c_import.SDL_DestroyRenderer;
 pub const SDL_SetRenderDrawColor = c_import.SDL_SetRenderDrawColor;
@@ -44,6 +45,7 @@ pub const SDL_EVENT_TEXT_INPUT = c_import.SDL_EVENT_TEXT_INPUT;
 pub const SDL_EVENT_MOUSE_BUTTON_DOWN = c_import.SDL_EVENT_MOUSE_BUTTON_DOWN;
 pub const SDL_EVENT_MOUSE_WHEEL = c_import.SDL_EVENT_MOUSE_WHEEL;
 pub const SDL_EVENT_WINDOW_RESIZED = c_import.SDL_EVENT_WINDOW_RESIZED;
+pub const SDL_EVENT_WINDOW_MOVED = c_import.SDL_EVENT_WINDOW_MOVED;
 
 pub const SDL_SetTextureScaleMode = c_import.SDL_SetTextureScaleMode;
 pub const SDL_SCALEMODE_LINEAR = c_import.SDL_SCALEMODE_LINEAR;

src/config.zig

@@ -0,0 +1,161 @@
+const std = @import("std");
+const fs = std.fs;
+const json = std.json;
+
+pub const Config = struct {
+    font_size: i32,
+    window_width: i32,
+    window_height: i32,
+    window_x: i32,
+    window_y: i32,
+
+    pub fn load(allocator: std.mem.Allocator) LoadError!Config {
+        const config_path = try getConfigPath(allocator);
+        defer allocator.free(config_path);
+
+        const file = fs.openFileAbsolute(config_path, .{}) catch |err| switch (err) {
+            error.FileNotFound => return error.ConfigNotFound,
+            else => return err,
+        };
+        defer file.close();
+
+        const content = try file.readToEndAlloc(allocator, 1024 * 1024);
+        defer allocator.free(content);
+
+        const parsed = try json.parseFromSlice(json.Value, allocator, content, .{});
+        defer parsed.deinit();
+
+        const root = parsed.value;
+        if (root != .object) return error.InvalidConfig;
+        const obj = root.object;
+
+        const font_size_val = obj.get("font_size") orelse return error.InvalidConfig;
+        const window_width_val = obj.get("window_width") orelse return error.InvalidConfig;
+        const window_height_val = obj.get("window_height") orelse return error.InvalidConfig;
+        const window_x_val = obj.get("window_x") orelse return error.InvalidConfig;
+        const window_y_val = obj.get("window_y") orelse return error.InvalidConfig;
+
+        if (font_size_val != .integer or window_width_val != .integer or window_height_val != .integer or
+            window_x_val != .integer or window_y_val != .integer)
+        {
+            return error.InvalidConfig;
+        }
+
+        return Config{
+            .font_size = @intCast(font_size_val.integer),
+            .window_width = @intCast(window_width_val.integer),
+            .window_height = @intCast(window_height_val.integer),
+            .window_x = @intCast(window_x_val.integer),
+            .window_y = @intCast(window_y_val.integer),
+        };
+    }
+
+    pub fn save(self: Config, allocator: std.mem.Allocator) SaveError!void {
+        const config_path = try getConfigPath(allocator);
+        defer allocator.free(config_path);
+
+        const config_dir = fs.path.dirname(config_path) orelse return error.InvalidPath;
+        fs.makeDirAbsolute(config_dir) catch |err| switch (err) {
+            error.PathAlreadyExists => {},
+            else => return err,
+        };
+
+        const content = try std.fmt.allocPrint(
+            allocator,
+            \\{{
+            \\  "font_size": {d},
+            \\  "window_width": {d},
+            \\  "window_height": {d},
+            \\  "window_x": {d},
+            \\  "window_y": {d}
+            \\}}
+            \\
+        ,
+            .{ self.font_size, self.window_width, self.window_height, self.window_x, self.window_y },
+        );
+        defer allocator.free(content);
+
+        const file = try fs.createFileAbsolute(config_path, .{ .truncate = true });
+        defer file.close();
+        try file.writeAll(content);
+    }
+
+    fn getConfigPath(allocator: std.mem.Allocator) ![]u8 {
+        const home = std.posix.getenv("HOME") orelse return error.HomeNotFound;
+        return try fs.path.join(allocator, &[_][]const u8{ home, ".config", "architect", "config.json" });
+    }
+};
+
+pub const LoadError = error{
+    ConfigNotFound,
+    InvalidConfig,
+    HomeNotFound,
+    InvalidPath,
+    OutOfMemory,
+} || fs.File.OpenError || fs.File.ReadError || json.ParseError(json.Scanner);
+
+pub const SaveError = error{
+    HomeNotFound,
+    InvalidPath,
+    OutOfMemory,
+} || fs.File.OpenError || fs.File.WriteError || fs.Dir.MakeError;
+
+test "Config - save and load" {
+    const allocator = std.testing.allocator;
+
+    const test_config = Config{
+        .font_size = 16,
+        .window_width = 1920,
+        .window_height = 1080,
+        .window_x = 100,
+        .window_y = 100,
+    };
+
+    const test_dir = try std.fs.cwd().makeOpenPath("test_config", .{});
+    defer std.fs.cwd().deleteTree("test_config") catch {};
+
+    const test_path = try fs.path.join(allocator, &[_][]const u8{ "test_config", "config.json" });
+    defer allocator.free(test_path);
+
+    const content = try std.fmt.allocPrint(
+        allocator,
+        \\{{
+        \\  "font_size": {d},
+        \\  "window_width": {d},
+        \\  "window_height": {d},
+        \\  "window_x": {d},
+        \\  "window_y": {d}
+        \\}}
+        \\
+    ,
+        .{ test_config.font_size, test_config.window_width, test_config.window_height, test_config.window_x, test_config.window_y },
+    );
+    defer allocator.free(content);
+
+    try test_dir.writeFile(.{ .sub_path = "config.json", .data = content });
+
+    const file = try fs.cwd().openFile(test_path, .{});
+    defer file.close();
+
+    const read_content = try file.readToEndAlloc(allocator, 1024 * 1024);
+    defer allocator.free(read_content);
+
+    const parsed = try json.parseFromSlice(json.Value, allocator, read_content, .{});
+    defer parsed.deinit();
+
+    const root = parsed.value;
+    try std.testing.expect(root == .object);
+    const obj = root.object;
+
+    const font_size_val = obj.get("font_size").?;
+    const window_width_val = obj.get("window_width").?;
+    const window_height_val = obj.get("window_height").?;
+    const window_x_val = obj.get("window_x").?;
+    const window_y_val = obj.get("window_y").?;
+
+    try std.testing.expectEqual(@as(i64, 16), font_size_val.integer);
+    try std.testing.expectEqual(@as(i64, 1920), window_width_val.integer);
+    try std.testing.expectEqual(@as(i64, 1080), window_height_val.integer);
+    try std.testing.expectEqual(@as(i64, 100), window_x_val.integer);
+    try std.testing.expectEqual(@as(i64, 100), window_y_val.integer);
+}