feat(content): routing to provided .blog paths

This is a starting point to dynamically loading `markdown` files as blog
entries. With this change the *doc/about.md* and *doc/blog.md* files
are no longer builded into the executable and instead read from the
filesystem during runtime (along with the new test file *doc/test.md*).

src/content.zig

@@ -1,11 +1,12 @@
 pub fn Content(App: type) type {
     return struct {
-        page: App.Model.Pages,
+        allocator: Allocator,
+        document: *const App.Model.Document,
 
         pub fn init(allocator: Allocator) @This() {
-            _ = allocator;
             return .{
-                .page = .blog,
+                .allocator = allocator,
+                .document = undefined,
             };
         }
 
@@ -22,10 +23,7 @@ pub fn Content(App: type) type {
 
         fn minSize(ctx: *anyopaque, size: zterm.Point) zterm.Point {
             const this: *const @This() = @ptrCast(@alignCast(ctx));
-            const text = switch (this.page) {
-                .about => @embedFile("about"),
-                .blog => @embedFile("blog"),
-            };
+            const text = this.document.content;
             var index: usize = 0;
             var new_size: zterm.Point = .{ .x = size.x };
 
@@ -48,17 +46,25 @@ pub fn Content(App: type) type {
         fn handle(ctx: *anyopaque, model: *App.Model, event: App.Event) !void {
             const this: *@This() = @ptrCast(@alignCast(ctx));
             switch (event) {
+                .init => this.document = &model.document,
                 .about => {
+                    model.page.deinit(this.allocator);
                     model.page = .about;
-                    model.document = .init(@embedFile("about"));
+
+                    model.document.deinit(this.allocator);
+                    model.document = .init(try std.fs.cwd().readFileAlloc("./doc/about.md", this.allocator, .unlimited));
+                    this.document = &model.document;
                 },
-                .blog => {
-                    model.page = .blog;
-                    model.document = .init(@embedFile("blog"));
+                .blog => |path| {
+                    model.page.deinit(this.allocator);
+                    model.page = .{ .blog = path };
+
+                    model.document.deinit(this.allocator);
+                    model.document = .init(try std.fs.cwd().readFileAlloc(if (path) |p| p else "./doc/blog.md", this.allocator, .unlimited));
+                    this.document = &model.document;
                 },
                 else => {},
             }
-            this.page = model.page;
         }
 
         fn content(ctx: *anyopaque, model: *const App.Model, cells: []zterm.Cell, size: zterm.Point) !void {
@@ -88,10 +94,6 @@ pub fn Content(App: type) type {
 
 pub fn Title(App: type) type {
     return struct {
-        pub fn init() @This() {
-            return .{};
-        }
-
         pub fn element(this: *@This()) App.Element {
             return .{
                 .ptr = this,
@@ -122,15 +124,8 @@ pub fn Title(App: type) type {
 
 pub fn InfoBanner(App: type) type {
     return struct {
-        left_text: []const u8,
-        right_text: []const u8,
-
-        pub fn init() @This() {
-            return .{
-                .left_text = "Build with zig",
-                .right_text = "Yves Biener (@yves-biener)",
-            };
-        }
+        left_text: []const u8 = "Build with zig",
+        right_text: []const u8 = "Yves Biener (@yves-biener)",
 
         pub fn element(this: *@This()) App.Element {
             return .{
@@ -141,7 +136,7 @@ pub fn InfoBanner(App: type) type {
             };
         }
 
-        fn content(ctx: *anyopaque, _: *const App.Model, cells: []zterm.Cell, size: zterm.Point) !void {
+        fn content(ctx: *anyopaque, model: *const App.Model, cells: []zterm.Cell, size: zterm.Point) !void {
             const this: *const @This() = @ptrCast(@alignCast(ctx));
             assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
 
@@ -154,6 +149,22 @@ pub fn InfoBanner(App: type) type {
                 cells[idx].cp = cp;
             }
 
+            switch (model.page) {
+                .about => {},
+                .blog => |path| if (path) |p| page: {
+                    const start_idx = (size.x -| p.len) / 2;
+                    if (start_idx <= this.left_text.len) break :page;
+
+                    for (start_idx.., p) |idx, cp| {
+                        // NOTE do not write over the contents of this `Container`'s `Size`
+                        if (idx == cells.len) break;
+
+                        cells[idx].style.fg = .default;
+                        cells[idx].cp = cp;
+                    }
+                },
+            }
+
             var start_idx = size.x -| this.right_text.len;
             if (start_idx <= this.left_text.len) start_idx = this.left_text.len + 1;
 

src/main.zig

@@ -7,8 +7,11 @@ pub fn main() !void {
     const allocator = gpa.allocator();
 
     var app: App = .init(.{
-        .document = .init(@embedFile("blog")),
+        .page = .about,
+        .document = .init(try std.fs.cwd().readFileAlloc("./doc/about.md", allocator, .unlimited)),
     });
+    defer app.model.deinit(allocator);
+
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -36,7 +39,7 @@ pub fn main() !void {
         }, .{});
         // title
         {
-            var title: Title = .init();
+            var title: Title = .{};
             try header.append(try .init(allocator, .{}, title.element()));
         }
         // about navigation button
@@ -76,7 +79,7 @@ pub fn main() !void {
     }
     // footer
     {
-        var info_banner: InfoBanner = .init();
+        var info_banner: InfoBanner = .{};
         const footer: App.Container = try .init(allocator, .{
             .size = .{
                 .dim = .{ .y = 1 },
@@ -98,6 +101,8 @@ pub fn main() !void {
         switch (event) {
             .key => |key| {
                 if (key.eql(.{ .cp = 'c', .mod = .{ .ctrl = true } })) app.quit();
+                // test if the event handling is working correctly
+                if (key.eql(.{ .cp = zterm.input.Space })) app.postEvent(.{ .blog = allocator.dupe(u8, "./doc/test.md") catch unreachable });
             },
             .err => |err| log.err("Received {s} with message: {s}", .{ @errorName(err.err), err.msg }),
             else => {},
@@ -134,10 +139,7 @@ const zlog = @import("zlog");
 const zterm = @import("zterm");
 const App = zterm.App(
     Model,
-    union(enum) {
-        about,
-        blog,
-    },
+    Model.Pages,
 );
 
 const contents = @import("content.zig");

src/model.zig

@@ -1,20 +1,41 @@
-page: Pages = .blog,
-document: Document = undefined,
+page: Pages,
+document: Document,
 
-pub const Pages = enum {
+pub fn deinit(this: *@This(), allocator: Allocator) void {
+    this.page.deinit(allocator);
+    this.document.deinit(allocator);
+
+    this.page = undefined;
+    this.document = undefined;
+}
+
+pub const Pages = union(enum) {
     about,
-    blog,
+    blog: ?[]const u8,
+
+    pub fn deinit(this: @This(), allocator: Allocator) void {
+        switch (this) {
+            .blog => |path| if (path) |p| allocator.free(p),
+            else => {},
+        }
+    }
 };
 
 pub const Document = struct {
     // preemble:
     title: ?[]const u8 = null,
     date: ?[]const u8 = null,
-    content: []const u8,
+    content: []const u8 = undefined,
+    ptr: []const u8,
+
+    const Preemble = enum {
+        title,
+        date,
+    };
 
     pub fn init(content: []const u8) @This() {
         if (std.mem.startsWith(u8, content, "---\n")) {
-            var document: @This() = .{ .content = undefined };
+            var document: @This() = .{ .ptr = content };
             // we assume the content includes a preemble
             var iter = std.mem.splitSequence(u8, content, "---\n");
             assert(iter.next().?.len == 0);
@@ -31,18 +52,20 @@ pub const Document = struct {
                     };
                 }
             }
-            document.content = iter.next().?;
+            document.content = iter.rest();
             return document;
         } else return .{
             .content = content,
+            .ptr = content,
         };
     }
-};
 
-const Preemble = enum {
-    title,
-    date,
+    pub fn deinit(this: *@This(), allocator: Allocator) void {
+        allocator.free(this.ptr);
+        this.* = .{ .ptr = undefined };
+    }
 };
 
 const std = @import("std");
 const assert = std.debug.assert;
+const Allocator = std.mem.Allocator;

src/navigation.zig

@@ -33,7 +33,11 @@ pub fn NavigationButton(App: type) fn (std.meta.FieldEnum(App.Event)) type {
                     switch (event) {
                         .about, .blog => this.highlight = event == page,
                         // TODO accept key input too?
-                        .mouse => |mouse| if (mouse.button == .left and mouse.kind == .release) this.queue.push(page),
+                        .mouse => |mouse| if (mouse.button == .left and mouse.kind == .release) this.queue.push(switch (page) {
+                            .about => .about,
+                            .blog => .{ .blog = null },
+                            else => @compileError("The provided navigation button event to trigger is not a `App.Model.Pages` enum variation."),
+                        }),
                         else => {},
                     }
                 }