From f58e4507f913bf3a6f5afee14650f058ecf6be84 Mon Sep 17 00:00:00 2001
From: Lucas Faria Mendes <lucas.oliveira1676@etec.sp.gov.br>
Date: Fri, 5 Dec 2025 05:18:27 -0300
Subject: codecrafters submit [skip ci]

---
 src/builtins.zig |  8 +++++++-
 src/main.zig     | 14 ++++++++++++--
 src/shell.zig    |  6 ++++++
 test_history.txt |  4 ++++
 4 files changed, 29 insertions(+), 3 deletions(-)
 create mode 100644 test_history.txt

diff --git a/src/builtins.zig b/src/builtins.zig
index 2a1eed7..011a923 100644
--- a/src/builtins.zig
+++ b/src/builtins.zig
@@ -1,7 +1,7 @@
 const std = @import("std");
 const path = @import("path.zig");
 
-const BUILTINS = [_][]const u8{ "exit", "echo", "type", "pwd", "cd" };
+const BUILTINS = [_][]const u8{ "exit", "echo", "type", "pwd", "cd", "history" };
 
 pub const CommandResult = enum {
     continue_loop,
@@ -115,3 +115,9 @@ pub fn executeType(allocator: std.mem.Allocator, stdout: anytype, args: ?[]const
         }
     }
 }
+
+pub fn executeHistory(stdout: anytype, history_list: []const []const u8) !void {
+    for (history_list, 1..) |cmd, idx| {
+        try stdout.print("    {d}  {s}\n", .{ idx, cmd });
+    }
+}
diff --git a/src/main.zig b/src/main.zig
index 74140cd..d16699d 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -285,6 +285,12 @@ pub fn main() !void {
     defer _ = gpa.deinit();
     const allocator = gpa.allocator();
 
+    var history = std.ArrayList([]const u8){};
+    defer {
+        for (history.items) |cmd| allocator.free(cmd);
+        history.deinit(allocator);
+    }
+
     const stdout = std.fs.File.stdout();
 
     while (true) {
@@ -297,6 +303,10 @@ pub fn main() !void {
             var stdout_writer = std.fs.File.stdout().writerStreaming(&.{});
             const stdout_iface = &stdout_writer.interface;
 
+            // Record command in history (duplicate it for long-term storage)
+            const cmd_copy = try allocator.dupe(u8, cmd);
+            try history.append(allocator, cmd_copy);
+
             if (std.mem.indexOfScalar(u8, cmd, '|')) |_| {
                 var segments = std.ArrayList([]const u8){};
                 defer segments.deinit(allocator);
@@ -326,7 +336,7 @@ pub fn main() !void {
 
                 if (segments.items.len == 1) {
                     const parsed = parser.parseCommand(cmd);
-                    const result = try shell.executeCommand(allocator, stdout_iface, parsed.name, parsed.args, parsed.output_redirect, parsed.error_redirect, parsed.append_output, parsed.append_error);
+                    const result = try shell.executeCommand(allocator, stdout_iface, parsed.name, parsed.args, parsed.output_redirect, parsed.error_redirect, parsed.append_output, parsed.append_error, history.items);
                     if (result == .exit_shell) break;
                 } else {
                     const result = try shell.executePipeline(allocator, stdout_iface, segments.items);
@@ -335,7 +345,7 @@ pub fn main() !void {
             } else {
                 const parsed = parser.parseCommand(cmd);
 
-                const result = try shell.executeCommand(allocator, stdout_iface, parsed.name, parsed.args, parsed.output_redirect, parsed.error_redirect, parsed.append_output, parsed.append_error);
+                const result = try shell.executeCommand(allocator, stdout_iface, parsed.name, parsed.args, parsed.output_redirect, parsed.error_redirect, parsed.append_output, parsed.append_error, history.items);
 
                 if (result == .exit_shell) break;
             }
diff --git a/src/shell.zig b/src/shell.zig
index 271e3ea..6f8bfef 100644
--- a/src/shell.zig
+++ b/src/shell.zig
@@ -19,9 +19,15 @@ pub fn executeCommand(
     error_redirect: ?[]const u8,
     append_output: ?[]const u8,
     append_error: ?[]const u8,
+    history_list: []const []const u8,
 ) !builtins.CommandResult {
     if (std.mem.eql(u8, cmd_name, "exit")) return builtins.executeExit();
 
+    if (std.mem.eql(u8, cmd_name, "history")) {
+        try builtins.executeHistory(stdout, history_list);
+        return .continue_loop;
+    }
+
     if (std.mem.eql(u8, cmd_name, "echo")) {
         if (error_redirect) |file| {
             const fd = try std.fs.cwd().createFile(file, .{});
diff --git a/test_history.txt b/test_history.txt
new file mode 100644
index 0000000..1f4d742
--- /dev/null
+++ b/test_history.txt
@@ -0,0 +1,4 @@
+echo hello
+pwd
+type echo
+history
-- 
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