From: Hugo Machet <mail@hmachet.com>
To: ~leon_plickat/nfm@lists.sr.ht
Cc: Hugo Machet <mail@hmachet.com>
Subject: [PATCH nfm] Add tab completion for files
Date: Sun, 22 May 2022 11:06:36 +0200
Message-Id: <20220522090636.6910-1-mail@hmachet.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

Implements: https://todo.sr.ht/~leon_plickat/nfm/17
---
 src/nfm.zig | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/src/nfm.zig b/src/nfm.zig
index d978210d4f9f..1414a5f81407 100644
--- a/src/nfm.zig
+++ b/src/nfm.zig
@@ -546,6 +546,19 @@ fn handleInputUserInput(in: spoon.Input) !void {
                 try handleReturnUserInput();
                 return;
             },
+            '\t' => {
+                var current = try util.codepointSliceToUtf8SlizeZAlloc(context.gpa, buffer.buffer.items);
+                defer context.gpa.free(current);
+
+                var it = mem.tokenize(u8, current, " ");
+                var buf: []const u8 = undefined;
+                while (it.next()) |tok| buf = tok;
+
+                if (buf.len < 2) return;
+                var comp = try completion(buf);
+                if (mem.eql(u8, comp, buf)) return;
+                try buffer.insertFormat(comp);
+            },
             127 => { // Backspace.
                 if (context.mode.user_input.history_index != null) return;
                 buffer.delete(.left, 1);
@@ -653,6 +666,48 @@ fn handleReturnUserInput() !void {
     }
 }
 
+/// Compare current input with files/directories names. Complete the name if
+/// there is only one match else only complete the common part.
+/// Case insensitive.
+fn completion(input: []const u8) ![]const u8 {
+    var found: std.ArrayListUnmanaged([:0]const u8) = .{};
+    defer found.deinit(context.gpa);
+
+    for (context.cwd.files.items) |file| {
+        if (!context.show_hidden and file.isHidden()) continue;
+        if (file.name.len <= input.len) continue;
+        if (ascii.startsWithIgnoreCase(file.name, input)) {
+            try found.append(context.gpa, file.name);
+        }
+    }
+
+    if (found.items.len == 0) {
+        return input;
+    } else if (found.items.len == 1) {
+        return found.items[0][input.len..];
+    } else {
+        var common: []const u8 = found.items[0];
+        var i: usize = 1;
+        while (i < found.items.len) : (i += 1) {
+            common = commonStart(common, found.items[i]);
+        }
+        return common[input.len..];
+    }
+}
+
+/// Compare two strings and return the common beginning part.
+/// Case insensitive.
+fn commonStart(a: []const u8, b: []const u8) []const u8 {
+    const len: usize = if (a.len < b.len) a.len else b.len;
+
+    var offset: usize = 0;
+    while (offset < len) : (offset += 1) {
+        if (ascii.toLower(a[offset]) != ascii.toLower(b[offset])) break;
+    }
+
+    return a[0..offset];
+}
+
 test {
     _ = @import("ini.zig");
     _ = @import("CommandTokenizer.zig");
-- 
2.36.1