From a5bc620142086b118af8324b4240295cb4859414 Mon Sep 17 00:00:00 2001
From: Lucas Faria Mendes <lucas.oliveira1676@etec.sp.gov.br>
Date: Fri, 5 Dec 2025 04:22:32 -0300
Subject: codecrafters submit [skip ci]

---
 src/main.zig | 108 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 100 insertions(+), 8 deletions(-)

(limited to 'src/main.zig')

diff --git a/src/main.zig b/src/main.zig
index b45cb7c..6922764 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -1,26 +1,118 @@
 const std = @import("std");
 const parser = @import("parser.zig");
 const shell = @import("shell.zig");
+const builtins = @import("builtins.zig");
 
-var stdin_buffer: [4096]u8 = undefined;
-var stdin_reader = std.fs.File.stdin().readerStreaming(&stdin_buffer);
-const stdin = &stdin_reader.interface;
+const BUILTINS = [_][]const u8{ "echo", "exit" };
 
-var stdout_writer = std.fs.File.stdout().writerStreaming(&.{});
-const stdout = &stdout_writer.interface;
+fn tryComplete(partial: []const u8) ?[]const u8 {
+    var matches: usize = 0;
+    var match: []const u8 = "";
 
+    for (BUILTINS) |builtin| {
+        if (std.mem.startsWith(u8, builtin, partial)) {
+            matches += 1;
+            match = builtin;
+            if (matches > 1) return null;
+        }
+    }
+
+    if (matches == 1) return match;
+    return null;
+}
+
+fn enableRawMode(fd: std.posix.fd_t) !std.posix.termios {
+    const original = try std.posix.tcgetattr(fd);
+    var raw = original;
+
+    // Disable canonical mode and echo
+    raw.lflag.ICANON = false;
+    raw.lflag.ECHO = false;
+
+    // Set minimum bytes and timeout for read
+    raw.cc[@intFromEnum(std.posix.V.MIN)] = 1;
+    raw.cc[@intFromEnum(std.posix.V.TIME)] = 0;
+
+    try std.posix.tcsetattr(fd, .FLUSH, raw);
+    return original;
+}
+
+fn disableRawMode(fd: std.posix.fd_t, original: std.posix.termios) !void {
+    try std.posix.tcsetattr(fd, .FLUSH, original);
+}
+
+fn readCommand(allocator: std.mem.Allocator) !?[]const u8 {
+    const stdin = std.fs.File.stdin();
+    const stdout = std.fs.File.stdout();
+
+    const stdin_fd = stdin.handle;
+
+    // Only use raw mode if stdin is a terminal
+    const is_tty = std.posix.isatty(stdin_fd);
+    const original_termios = if (is_tty) try enableRawMode(stdin_fd) else null;
+    defer if (original_termios) |orig| disableRawMode(stdin_fd, orig) catch {};
+
+    var buffer = std.ArrayList(u8){};
+    defer buffer.deinit(allocator);
+
+    var byte: [1]u8 = undefined;
+
+    while (true) {
+        const bytes_read = try stdin.read(&byte);
+        if (bytes_read == 0) return null;
+
+        const c = byte[0];
+
+        if (c == '\n' or c == '\r') {
+            return try buffer.toOwnedSlice(allocator);
+        } else if (c == '\t' and is_tty) {
+            const partial = buffer.items;
+            if (partial.len > 0 and std.mem.indexOf(u8, partial, " ") == null) {
+                if (tryComplete(partial)) |completion| {
+                    const remaining = completion[partial.len..];
+                    try stdout.writeAll(remaining);
+                    try stdout.writeAll(" ");
+                    try buffer.appendSlice(allocator, remaining);
+                    try buffer.append(allocator, ' ');
+                }
+            }
+        } else if ((c == 127 or c == 8) and is_tty) {
+            if (buffer.items.len > 0) {
+                _ = buffer.pop();
+                try stdout.writeAll("\x08 \x08");
+            }
+        } else if (c >= 32 and c < 127) {
+            try buffer.append(allocator, c);
+            if (is_tty) {
+                try stdout.writeAll(&[_]u8{c});
+            }
+        } else if (c == '\t' and !is_tty) {
+            // When not a TTY, tab is part of the input (for testing)
+            try buffer.append(allocator, c);
+        }
+    }
+}
 pub fn main() !void {
     var gpa = std.heap.GeneralPurposeAllocator(.{}){};
     defer _ = gpa.deinit();
     const allocator = gpa.allocator();
 
+    const stdout = std.fs.File.stdout();
+
     while (true) {
-        try stdout.print("$ ", .{});
+        try stdout.writeAll("$ ");
 
-        const command = try stdin.takeDelimiter('\n');
+        const command = try readCommand(allocator);
         if (command) |cmd| {
+            defer allocator.free(cmd);
+            try stdout.writeAll("\n");
+
             const parsed = parser.parseCommand(cmd);
-            const result = try shell.executeCommand(allocator, stdout, parsed.name, parsed.args, parsed.output_redirect, parsed.error_redirect, parsed.append_output, parsed.append_error);
+
+            var stdout_writer = std.fs.File.stdout().writerStreaming(&.{});
+            const stdout_iface = &stdout_writer.interface;
+
+            const result = try shell.executeCommand(allocator, stdout_iface, parsed.name, parsed.args, parsed.output_redirect, parsed.error_redirect, parsed.append_output, parsed.append_error);
 
             if (result == .exit_shell) break;
         } else {
-- 
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