move tax type to enum

src/analytics/analysis.zig

@@ -17,10 +17,27 @@ pub const BreakdownItem = struct {
     weight: f64, // fraction of total (0.0 - 1.0)
 };
 
+/// Tax type classification for accounts.
+pub const TaxType = enum {
+    taxable,
+    roth,
+    traditional,
+    hsa,
+
+    pub fn label(self: TaxType) []const u8 {
+        return switch (self) {
+            .taxable => "Taxable",
+            .roth => "Roth (Post-Tax)",
+            .traditional => "Traditional (Pre-Tax)",
+            .hsa => "HSA (Triple Tax-Free)",
+        };
+    }
+};
+
 /// Account tax type classification entry, parsed from accounts.srf.
 pub const AccountTaxEntry = struct {
     account: []const u8,
-    tax_type: []const u8,
+    tax_type: TaxType,
 };
 
 /// Parsed account metadata.
@@ -31,7 +48,6 @@ pub const AccountMap = struct {
     pub fn deinit(self: *AccountMap) void {
         for (self.entries) |e| {
             self.allocator.free(e.account);
-            self.allocator.free(e.tax_type);
         }
         self.allocator.free(self.entries);
     }
@@ -40,22 +56,13 @@ pub const AccountMap = struct {
     pub fn taxTypeFor(self: AccountMap, account: []const u8) []const u8 {
         for (self.entries) |e| {
             if (std.mem.eql(u8, e.account, account)) {
-                return taxTypeLabel(e.tax_type);
+                return e.tax_type.label();
             }
         }
         return "Unknown";
     }
 };
 
-/// Map raw tax_type strings to display labels.
-fn taxTypeLabel(raw: []const u8) []const u8 {
-    if (std.mem.eql(u8, raw, "taxable")) return "Taxable";
-    if (std.mem.eql(u8, raw, "roth")) return "Roth (Post-Tax)";
-    if (std.mem.eql(u8, raw, "traditional")) return "Traditional (Pre-Tax)";
-    if (std.mem.eql(u8, raw, "hsa")) return "HSA (Triple Tax-Free)";
-    return raw;
-}
-
 /// Parse an accounts.srf file into an AccountMap.
 /// Each record has: account::<NAME>,tax_type::<TYPE>
 pub fn parseAccountsFile(allocator: std.mem.Allocator, data: []const u8) !AccountMap {
@@ -63,7 +70,6 @@ pub fn parseAccountsFile(allocator: std.mem.Allocator, data: []const u8) !Accoun
     errdefer {
         for (entries.items) |e| {
             allocator.free(e.account);
-            allocator.free(e.tax_type);
         }
         entries.deinit(allocator);
     }
@@ -76,7 +82,7 @@ pub fn parseAccountsFile(allocator: std.mem.Allocator, data: []const u8) !Accoun
         const entry = record.to(AccountTaxEntry) catch continue;
         try entries.append(allocator, .{
             .account = try allocator.dupe(u8, entry.account),
-            .tax_type = try allocator.dupe(u8, entry.tax_type),
+            .tax_type = entry.tax_type,
         });
     }
 
@@ -287,13 +293,11 @@ test "parseAccountsFile" {
     try std.testing.expectEqualStrings("Unknown", am.taxTypeFor("Nonexistent"));
 }
 
-test "taxTypeLabel" {
+test "TaxType.label" {
-    try std.testing.expectEqualStrings("Taxable", taxTypeLabel("taxable"));
+    try std.testing.expectEqualStrings("Taxable", TaxType.taxable.label());
-    try std.testing.expectEqualStrings("Roth (Post-Tax)", taxTypeLabel("roth"));
+    try std.testing.expectEqualStrings("Roth (Post-Tax)", TaxType.roth.label());
-    try std.testing.expectEqualStrings("Traditional (Pre-Tax)", taxTypeLabel("traditional"));
+    try std.testing.expectEqualStrings("Traditional (Pre-Tax)", TaxType.traditional.label());
-    try std.testing.expectEqualStrings("HSA (Triple Tax-Free)", taxTypeLabel("hsa"));
+    try std.testing.expectEqualStrings("HSA (Triple Tax-Free)", TaxType.hsa.label());
-    // Unknown type returns raw string
-    try std.testing.expectEqualStrings("custom_type", taxTypeLabel("custom_type"));
 }
 
 test "mapToSortedBreakdown" {