feat: output mapping + state path helpers

Add three helper functions for logical-to-physical output mapping and
state file paths: output_for maps H|V to physical connectors, wall_file_for
returns config paths, pid_file_for returns cache paths.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

2 files changed, 47 insertions, 0 deletions

diff --git a/tests/wallp.bats b/tests/wallp.bats
index 0ffed89..b5c9ff7 100644
--- a/tests/wallp.bats
+++ b/tests/wallp.bats
@@ -105,3 +105,25 @@ teardown() {
   persist_theme "abc"
   [ "$(cat "$HOME/.config/wallp/theme")" = "abc" ]
 }
+
+@test "output_for maps logical to physical" {
+  CONF_OUTPUT_H="DP-1"; CONF_OUTPUT_V="DP-3"
+  run output_for H
+  [ "$output" = "DP-1" ]
+  run output_for V
+  [ "$output" = "DP-3" ]
+}
+
+@test "wall_file_for returns config paths" {
+  run wall_file_for H
+  [ "$output" = "$HOME/.config/wallp/wall_h" ]
+  run wall_file_for V
+  [ "$output" = "$HOME/.config/wallp/wall_v" ]
+}
+
+@test "pid_file_for returns cache paths" {
+  run pid_file_for H
+  [ "$output" = "$HOME/.cache/wallp/H.pid" ]
+  run pid_file_for V
+  [ "$output" = "$HOME/.cache/wallp/V.pid" ]
+}
diff --git a/wallp b/wallp
index 6f14341..0827fa4 100644
--- a/wallp
+++ b/wallp
@@ -95,6 +95,31 @@ resolve_theme() {
   printf '%s\n' "sexy-splurge"
 }
 
+# Maps logical output (H|V) to physical connector name from config.
+output_for() {
+  case "$1" in
+    H) printf '%s\n' "$CONF_OUTPUT_H" ;;
+    V) printf '%s\n' "$CONF_OUTPUT_V" ;;
+    *) echo "wallp: unknown logical output '$1'" >&2; return 1 ;;
+  esac
+}
+
+# Returns path to saved wall state for logical output (H|V).
+wall_file_for() {
+  case "$1" in
+    H) printf '%s\n' "$HOME/.config/wallp/wall_h" ;;
+    V) printf '%s\n' "$HOME/.config/wallp/wall_v" ;;
+  esac
+}
+
+# Returns path to PID file for logical output (H|V).
+pid_file_for() {
+  case "$1" in
+    H) printf '%s\n' "$HOME/.cache/wallp/H.pid" ;;
+    V) printf '%s\n' "$HOME/.cache/wallp/V.pid" ;;
+  esac
+}
+
 main() {
   return 0
 }