From e0832b1bd8e6f6f5ff6cfc1f639792971f938208 Mon Sep 17 00:00:00 2001
From: eljamm <fedi.jamoussi@protonmail.ch>
Date: Thu, 8 Aug 2024 12:51:38 +0100
Subject: [PATCH] taler-merchant: fix wrong templates and spa dirs

The taler-exchange package is wrongfully used when initializing the
`templates` and `spa` directories, which results in the merchant not
working.

Replacing this relative path searching with an absolute path pointing to
the correct merchant directories fixes this.
---
 .../0001-add-TALER_TEMPLATING_init_path.patch | 75 +++++++++++++++++++
 pkgs/by-name/ta/taler-exchange/package.nix    |  2 +
 pkgs/by-name/ta/taler-merchant/package.nix    | 24 +++++-
 3 files changed, 97 insertions(+), 4 deletions(-)
 create mode 100644 pkgs/by-name/ta/taler-exchange/0001-add-TALER_TEMPLATING_init_path.patch

diff --git a/pkgs/by-name/ta/taler-exchange/0001-add-TALER_TEMPLATING_init_path.patch b/pkgs/by-name/ta/taler-exchange/0001-add-TALER_TEMPLATING_init_path.patch
new file mode 100644
index 000000000000..60ea8051366e
--- /dev/null
+++ b/pkgs/by-name/ta/taler-exchange/0001-add-TALER_TEMPLATING_init_path.patch
@@ -0,0 +1,75 @@
+From 3ca51717bbb7643eb0629729d0680cca75ce34c8 Mon Sep 17 00:00:00 2001
+From: eljamm <fedi.jamoussi@protonmail.ch>
+Date: Wed, 14 Aug 2024 11:14:41 +0100
+Subject: [PATCH] add TALER_TEMPLATING_init_path
+
+The merchant uses `TALER_TEMPLATING_init` function from the exchange's
+headers, which makes it harder to patch in the correct directory.
+
+To circumvent this, a similar function that takes the templates path
+directly is added.
+---
+ src/include/taler_templating_lib.h |  9 +++++++++
+ src/templating/templating_api.c    | 25 +++++++++++++++++++++++++
+ 2 files changed, 34 insertions(+)
+
+diff --git a/src/include/taler_templating_lib.h b/src/include/taler_templating_lib.h
+index 6af6db715..343004ef1 100644
+--- a/src/include/taler_templating_lib.h
++++ b/src/include/taler_templating_lib.h
+@@ -120,6 +120,16 @@ TALER_TEMPLATING_reply_error (struct MHD_Connection *connection,
+ enum GNUNET_GenericReturnValue
+ TALER_TEMPLATING_init (const char *subsystem);
+
++/**
++ * Preload templates from path.
++ *
++ * @param subsystem name of the subsystem, "merchant" or "exchange"
++ * @param path name of the absolute template path
++ * @return #GNUNET_OK on success
++ */
++enum GNUNET_GenericReturnValue
++TALER_TEMPLATING_init_path (const char *subsystem, const char *path);
++
+
+ /**
+  * Nicely shut down templating subsystem.
+diff --git a/src/templating/templating_api.c b/src/templating/templating_api.c
+index 88a17c682..a9afa2b70 100644
+--- a/src/templating/templating_api.c
++++ b/src/templating/templating_api.c
+@@ -506,6 +506,31 @@ TALER_TEMPLATING_init (const char *subsystem)
+ }
+
+
++enum GNUNET_GenericReturnValue
++TALER_TEMPLATING_init_path (const char *subsystem, const char *path)
++{
++  char *dn;
++  int ret;
++
++  {
++    GNUNET_asprintf (&dn,
++                     "%s/%s/templates/",
++                     path,
++                     subsystem);
++  }
++  ret = GNUNET_DISK_directory_scan (dn,
++                                    &load_template,
++                                    NULL);
++  GNUNET_free (dn);
++  if (-1 == ret)
++  {
++    GNUNET_break (0);
++    return GNUNET_SYSERR;
++  }
++  return GNUNET_OK;
++}
++
++
+ void
+ TALER_TEMPLATING_done (void)
+ {
+--
+2.45.2
+
diff --git a/pkgs/by-name/ta/taler-exchange/package.nix b/pkgs/by-name/ta/taler-exchange/package.nix
index 4bea04b1c29e..5460db04a5e4 100644
--- a/pkgs/by-name/ta/taler-exchange/package.nix
+++ b/pkgs/by-name/ta/taler-exchange/package.nix
@@ -34,6 +34,8 @@ stdenv.mkDerivation {
     hash = "sha256-yHRRMlqFA2OiFg0rBVzn7130wyVaxKn2dChFTPnVtbs=";
   };
 
+  patches = [ ./0001-add-TALER_TEMPLATING_init_path.patch ];
+
   nativeBuildInputs = [
     autoreconfHook
     pkg-config
diff --git a/pkgs/by-name/ta/taler-merchant/package.nix b/pkgs/by-name/ta/taler-merchant/package.nix
index b5762464c3ab..dcc45968894f 100644
--- a/pkgs/by-name/ta/taler-merchant/package.nix
+++ b/pkgs/by-name/ta/taler-merchant/package.nix
@@ -8,6 +8,7 @@
   libtool,
   pkg-config,
   autoreconfHook,
+  makeWrapper,
   jq,
 }:
 
@@ -36,9 +37,20 @@ stdenv.mkDerivation {
     ln -s ${taler-wallet-core}/spa.html $sourceRoot/contrib/
   '';
 
+  # Use an absolute path for `templates` and `spa` directories, else a relative
+  # path to the `taler-exchange` package is used.
+  postPatch = ''
+    substituteInPlace src/backend/taler-merchant-httpd.c \
+      --replace-fail 'TALER_TEMPLATING_init ("merchant");' "TALER_TEMPLATING_init_path (\"merchant\", \"$out/share/taler\");"
+
+    substituteInPlace src/backend/taler-merchant-httpd_spa.c \
+      --replace-fail 'GNUNET_DISK_directory_scan (dn,' "GNUNET_DISK_directory_scan (\"$out/share/taler/merchant/spa/\","
+  '';
+
   nativeBuildInputs = [
     pkg-config
     autoreconfHook
+    makeWrapper
   ];
 
   buildInputs = taler-exchange.buildInputs ++ [
@@ -59,10 +71,14 @@ stdenv.mkDerivation {
     popd
   '';
 
-  configureFlags = [
-    "--with-gnunet=${gnunet}"
-    "--with-exchange=${taler-exchange}"
-  ];
+  # NOTE: The executables that need database access fail to detect the
+  # postgresql library in `$out/lib/taler`, so we need to wrap them.
+  postInstall = ''
+    for exec in dbinit httpd webhook wirewatch depositcheck exchange; do
+      wrapProgram $out/bin/taler-merchant-$exec \
+        --prefix LD_LIBRARY_PATH : "$out/lib/taler"
+    done
+  '';
 
   enableParallelBuilding = true;