Unify input handling.

6 files changed, 99 insertions, 45 deletions

diff --git a/src/cmd/copy.zig b/src/cmd/copy.zig
index 1c3c3ba..733dc47 100644
--- a/src/cmd/copy.zig
+++ b/src/cmd/copy.zig
@@ -46,36 +46,20 @@ pub const Copy = struct {
                 };
                 defer dest_file.close();
 
-                // Read from stdin and write to file until EOF (Ctrl+Z on DOS)
-                const stdin = std.io.getStdIn().reader();
+                // Read from input source and write to file until EOF (Ctrl+Z on DOS)
                 var line_count: u32 = 0;
+                var reader = ctx.input_reader;
 
                 while (true) {
-                    if (stdin.readUntilDelimiterOrEofAlloc(ctx.allocator, '\n', 4096)) |maybe_line| {
-                        if (maybe_line) |line| {
-                            defer ctx.allocator.free(line);
-
-                            // Check for Ctrl+Z (EOF marker)
-                            if (line.len == 1 and line[0] == 26) { // ASCII 26 = Ctrl+Z
-                                break;
-                            }
-
-                            // Remove trailing \r if present (Windows line endings)
-                            const clean_line = if (line.len > 0 and line[line.len - 1] == '\r')
-                                line[0 .. line.len - 1]
-                            else
-                                line;
-
-                            // Write line to file with DOS line ending
-                            try dest_file.writeAll(clean_line);
-                            try dest_file.writeAll("\r\n");
-                            line_count += 1;
-                        } else {
-                            // EOF reached
-                            break;
-                        }
-                    } else |_| {
-                        // Error reading input
+                    if (try reader.readLine(ctx.allocator)) |line| {
+                        defer ctx.allocator.free(line);
+
+                        // Write line to file with DOS line ending
+                        try dest_file.writeAll(line);
+                        try dest_file.writeAll("\r\n");
+                        line_count += 1;
+                    } else {
+                        // EOF reached
                         break;
                     }
                 }
diff --git a/src/cmd/external.zig b/src/cmd/external.zig
index 0f4e65f..3aaa7af 100644
--- a/src/cmd/external.zig
+++ b/src/cmd/external.zig
@@ -14,7 +14,11 @@ pub const External = struct {
 
     pub fn eval(external: External, ctx: CommandContext) !CommandStatus {
         const allocator = ctx.allocator;
-        const input_source = ctx.input_source;
+        // Extract input_source from the input_reader for external command logic
+        const input_source = switch (ctx.input_reader) {
+            .source => |source| source,
+            .stdin => null,
+        };
 
         // Check if we need to capture output (not going to stdout)
         const needs_capture = switch (ctx.output_writer) {
diff --git a/src/cmd/lib/types.zig b/src/cmd/lib/types.zig
index f663a64..f6a32c0 100644
--- a/src/cmd/lib/types.zig
+++ b/src/cmd/lib/types.zig
@@ -72,6 +72,59 @@ pub const InputSource = struct {
     }
 };
 
+pub const StdinInputReader = struct {
+    pub fn readLine(self: *StdinInputReader, allocator: Allocator) !?[]const u8 {
+        _ = self;
+        const stdin = std.io.getStdIn().reader();
+
+        // Read line from stdin with proper DOS handling
+        const line = stdin.readUntilDelimiterOrEofAlloc(allocator, '\n', 4096) catch |err| switch (err) {
+            error.StreamTooLong => {
+                // Line too long, skip to next line
+                while (true) {
+                    const ch = stdin.readByte() catch return null;
+                    if (ch == '\n') break;
+                }
+                return try allocator.dupe(u8, "");
+            },
+            else => return null,
+        };
+
+        if (line) |input| {
+            // Check for Ctrl+Z (EOF marker) - ASCII 26 or ^Z text
+            if ((input.len == 1 and input[0] == 26) or
+                (input.len == 2 and input[0] == '^' and input[1] == 'Z'))
+            {
+                allocator.free(input);
+                return null; // EOF
+            }
+
+            // Remove trailing \r if present (DOS line endings)
+            if (input.len > 0 and input[input.len - 1] == '\r') {
+                const trimmed = try allocator.dupe(u8, input[0 .. input.len - 1]);
+                allocator.free(input);
+                return trimmed;
+            } else {
+                return input;
+            }
+        } else {
+            return null; // EOF
+        }
+    }
+};
+
+pub const InputReader = union(enum) {
+    source: *InputSource,
+    stdin: *StdinInputReader,
+
+    pub fn readLine(self: *InputReader, allocator: Allocator) !?[]const u8 {
+        switch (self.*) {
+            .source => |source| return source.readLine(allocator),
+            .stdin => |stdin| return stdin.readLine(allocator),
+        }
+    }
+};
+
 pub const OutputWriter = union(enum) {
     capture: *OutputCapture,
     stdout: *StdoutOutputCapture,
@@ -89,14 +142,14 @@ pub const ExecuteCommandFn = *const fn (Command, Allocator, ?*OutputCapture, ?*I
 pub const CommandContext = struct {
     allocator: Allocator,
     output_writer: OutputWriter,
-    input_source: ?*InputSource,
+    input_reader: InputReader,
     execute_command: ExecuteCommandFn,
 
-    pub fn init(allocator: Allocator, output_writer: OutputWriter, input_source: ?*InputSource, execute_command: ExecuteCommandFn) CommandContext {
+    pub fn init(allocator: Allocator, output_writer: OutputWriter, input_reader: InputReader, execute_command: ExecuteCommandFn) CommandContext {
         return CommandContext{
             .allocator = allocator,
             .output_writer = output_writer,
-            .input_source = input_source,
+            .input_reader = input_reader,
             .execute_command = execute_command,
         };
     }
diff --git a/src/cmd/path.zig b/src/cmd/path.zig
index 009621f..e0c549f 100644
--- a/src/cmd/path.zig
+++ b/src/cmd/path.zig
@@ -8,7 +8,6 @@ const CommandContext = types.CommandContext;
 pub const PathGet = struct {
     pub fn eval(path_get: PathGet, ctx: CommandContext) !CommandStatus {
         _ = path_get;
-        _ = ctx.input_source;
 
         const current_path = std.process.getEnvVarOwned(ctx.allocator, "PATH") catch |err| switch (err) {
             error.EnvironmentVariableNotFound => {
diff --git a/src/cmd/sort.zig b/src/cmd/sort.zig
index 0f73940..79616e9 100644
--- a/src/cmd/sort.zig
+++ b/src/cmd/sort.zig
@@ -18,18 +18,24 @@ pub const Sort = struct {
             lines.deinit();
         }
 
-        // Read input lines
-        if (ctx.input_source) |source| {
-            // Read from input redirection
-            while (try source.readLine(ctx.allocator)) |line| {
-                try lines.append(line);
-            }
-        } else {
-            // Read from stdin (simplified - just show message)
-            const msg = "SORT: Use input redirection (< file.txt) to sort file contents\n";
-            var writer = ctx.output_writer;
-            try writer.write(msg);
-            return CommandStatus{ .Code = 0 };
+        // Read input lines from unified input reader
+        var reader = ctx.input_reader;
+
+        // Check if we're reading from stdin vs file redirection for DOS-authentic behavior
+        switch (ctx.input_reader) {
+            .stdin => {
+                // Reading from interactive stdin - show usage message (DOS behavior)
+                const msg = "SORT: Use input redirection (< file.txt) to sort file contents\n";
+                var writer = ctx.output_writer;
+                try writer.write(msg);
+                return CommandStatus{ .Code = 0 };
+            },
+            .source => {
+                // Read from input redirection
+                while (try reader.readLine(ctx.allocator)) |line| {
+                    try lines.append(line);
+                }
+            },
         }
 
         // Sort the lines
diff --git a/src/eval.zig b/src/eval.zig
index 3381302..1b9858e 100644
--- a/src/eval.zig
+++ b/src/eval.zig
@@ -28,6 +28,8 @@ const OutputCapture = cmdTypes.OutputCapture;
 const StdoutOutputCapture = cmdTypes.StdoutOutputCapture;
 const OutputWriter = cmdTypes.OutputWriter;
 const InputSource = cmdTypes.InputSource;
+const StdinInputReader = cmdTypes.StdinInputReader;
+const InputReader = cmdTypes.InputReader;
 const CommandContext = cmdTypes.CommandContext;
 
 const STDOUT_BUFFER_SIZE: usize = 1024;
@@ -44,7 +46,13 @@ pub fn executeCommandWithOutput(command: Command, allocator: Allocator, output_c
     else
         OutputWriter{ .stdout = &stdout_capture };
 
-    const ctx = CommandContext.init(allocator, output_writer, input_source, executeCommandWithOutput);
+    var stdin_reader = StdinInputReader{};
+    const input_reader = if (input_source) |source|
+        InputReader{ .source = source }
+    else
+        InputReader{ .stdin = &stdin_reader };
+
+    const ctx = CommandContext.init(allocator, output_writer, input_reader, executeCommandWithOutput);
 
     switch (command) {
         .Empty => return CommandStatus{ .Code = 0 },