From 06b160f341bd128fc951a5c65c88a50bab528096 Mon Sep 17 00:00:00 2001
From: Sveinung Kvilhaugsvik <sveinung84@users.sourceforge.net>
Date: Mon, 22 Feb 2021 22:31:35 +0100
Subject: [PATCH] Ruledit: detect duplicate requirements.

Add the new function get_first_redundant_req(), currently only able to
detect exact duplicates in requirement vectors. Plug it into
req_vec_suggest_improvement() so everyone looking for generic advice on
requirement vector improvements gets it.

This makes Ruledit find duplicates in action enabler requirements.

See osdn #41633
---
 common/requirements.c | 73 ++++++++++++++++++++++++++++++++++++++++++-
 common/requirements.h |  4 +++
 2 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/common/requirements.c b/common/requirements.c
index 25d2f89663..4e0fe8bb78 100644
--- a/common/requirements.c
+++ b/common/requirements.c
@@ -3821,6 +3821,68 @@ req_vec_get_first_missing_univ(const struct requirement_vector *vec,
   return NULL;
 }
 
+/**********************************************************************//**
+  Returns the first redundant requirement in the specified requirement
+  vector with suggested solutions or NULL if no redundant requirements were
+  found.
+  It is the responsibility of the caller to free the suggestion when it is
+  done with it.
+  @param vec the requirement vector to look in.
+  @param get_num function that returns the requirement vector's number in
+                 the parent item.
+  @param parent_item the item that owns the vector.
+  @return the first redundant requirement found.
+**************************************************************************/
+struct req_vec_problem *
+req_vec_get_first_redundant_req(const struct requirement_vector *vec,
+                                requirement_vector_number get_num,
+                                const void *parent_item)
+{
+  int i, j;
+  req_vec_num_in_item vec_num;
+
+  if (vec == NULL || requirement_vector_size(vec) == 0) {
+    /* No vector. */
+    return NULL;
+  }
+
+  if (get_num == NULL || parent_item == NULL) {
+    vec_num = 0;
+  } else {
+    vec_num = get_num(parent_item, vec);
+  }
+
+  /* Look for repeated requirements */
+  for (i = 0; i < requirement_vector_size(vec) - 1; i++) {
+    struct requirement *preq = requirement_vector_get(vec, i);
+    for (j = i + 1; j < requirement_vector_size(vec); j++) {
+      struct requirement *nreq = requirement_vector_get(vec, j);
+
+      if (are_requirements_equal(preq, nreq)) {
+        struct req_vec_problem *problem;
+
+        problem = req_vec_problem_new(2,
+            N_("Requirements {%s} and {%s} are the same."),
+            req_to_fstring(preq), req_to_fstring(nreq));
+
+        /* The solution is to remove one of the redundant requirements. */
+        problem->suggested_solutions[0].operation = RVCO_REMOVE;
+        problem->suggested_solutions[0].vector_number = vec_num;
+        problem->suggested_solutions[0].req = *preq;
+
+        problem->suggested_solutions[1].operation = RVCO_REMOVE;
+        problem->suggested_solutions[1].vector_number = vec_num;
+        problem->suggested_solutions[1].req = *nreq;
+
+        /* Only the first redundancy is reported. */
+        return problem;
+      }
+    }
+  }
+
+  return NULL;
+}
+
 /**********************************************************************//**
   Returns a suggestion to improve the specified requirement vector or NULL
   if nothing to improve is found. It is the responsibility of the caller to
@@ -3837,8 +3899,17 @@ req_vec_suggest_improvement(const struct requirement_vector *vec,
                             requirement_vector_number get_num,
                             const void *parent_item)
 {
+  struct req_vec_problem *out;
+
   /* Check if a universal that never will appear in the game is checked. */
-  return req_vec_get_first_missing_univ(vec, get_num, parent_item);
+  out = req_vec_get_first_missing_univ(vec, get_num, parent_item);
+  if (out != NULL) {
+    return out;
+  }
+
+  /* Check if a requirement is redundant. */
+  out = req_vec_get_first_redundant_req(vec, get_num, parent_item);
+  return out;
 }
 
 /**********************************************************************//**
diff --git a/common/requirements.h b/common/requirements.h
index fbb9f47dd1..c98ce5525f 100644
--- a/common/requirements.h
+++ b/common/requirements.h
@@ -244,6 +244,10 @@ req_vec_get_first_missing_univ(const struct requirement_vector *vec,
                                requirement_vector_number get_num,
                                const void *parent_item);
 struct req_vec_problem *
+req_vec_get_first_redundant_req(const struct requirement_vector *vec,
+                                requirement_vector_number get_num,
+                                const void *parent_item);
+struct req_vec_problem *
 req_vec_suggest_improvement(const struct requirement_vector *vec,
                             requirement_vector_number get_num,
                             const void *parent_item);
-- 
2.20.1