Implemented upgrade with conflicts and stuff

.gitignore

@@ -1,3 +1,5 @@
+/old/
+
 .idea
 
 # Python.gitignore

upgrade.sh

@@ -1,28 +1,174 @@
 #!/bin/bash
 
-problem_dir=$1
+set -euo pipefail
 
-set -ex
+function errcho {
+    >&2 echo "$@"
+}
 
-mkdir -p "${problem_dir}/scripts"
+function recreate_dir {
+    dir=$1
+    mkdir -p "${dir}"
+    ls -A1 "${dir}" | while read file; do
+        [ -z "${file}" ] && continue
+        rm -rf "${dir}/${file}"
+    done
+}
 
-"rm ${problem_dir}/
-cp verify.py $problem_dir/scripts
-cp common.sh $problem_dir/scripts/
-cp compile.sh $problem_dir/
-cp gen.sh $problem_dir/gen/
-cp test.sh $problem_dir/gen/
-cp validate.sh $problem_dir/gen/
-cp problem.gitignore $problem_dir/.gitignore
+function usage {
+	errcho "Usage: upgrade.sh <problem-dir>"
+	exit 2
+}
 
-for folder in gen validator checker; do
-    cat > $problem_dir/$folder/Makefile << EOF
-all:`cd $problem_dir/$folder/; for file in \`ls *.cpp\`; do echo -n " ${file%.cpp}.exe"; done`
+[ $# -eq 1 ] || usage
 
-clean:
-	rm -f *.exe
+problem_dir="$1"
+problem_scripts="${problem_dir}/scripts"
+source_current_scripts="scripts"
+old_scripts="old"
+problem_old_scripts_version_file="${problem_dir}/.scripts_version"
+dry_run="false"
 
-%.exe: %.cpp testlib.h
-	g++ -std=gnu++1y -Wall -Wextra -Wshadow -O2 $< -o \$@
-EOF
-done"
+
+if [ -z "${problem_dir}" ]; then
+    errcho "Problem directory is not specified."
+    exit 2
+fi
+
+if [ ! -d "${problem_dir}" ]; then
+    errcho "Problem directory '${problem_dir}' not found"
+    exit 4
+fi
+
+
+if [ -f "${problem_old_scripts_version_file}" ]; then
+    old_scripts_version="$(cat "${problem_old_scripts_version_file}")"
+else
+    old_scripts_version="$(git log --pretty=format:"%H" | tail -n 1)"
+fi
+
+if ! git show -s --oneline "${old_scripts_version}" > /dev/null; then
+    errcho "Problem scripts version '${old_scripts_version}' not found in this source repo"
+    exit 4
+fi
+
+
+function source_current_scripts_version {
+    ret=0
+    tag="$(git describe --tags | head -1)" || ret=$?
+    if [ "${ret}" -eq 0 ]; then
+        version="${tag}"
+    else
+        version="$(git log --pretty=format:'%H' -n 1)"
+    fi
+    echo "${version}"
+}
+
+function list_dir_files {
+    dir="$1"
+    pushd "${dir}" > /dev/null 2>&1
+    find . -type f
+    popd  > /dev/null 2>&1
+}
+
+function get_all_scripts_files {
+    {
+        list_dir_files "${source_current_scripts}"
+        list_dir_files "${problem_scripts}"
+    } | cut -d/ -f2- | sort | uniq
+}
+
+has_conflicts="false"
+declare -a conflict_list
+conflict_index=0
+
+function push_conflict {
+    status="FAIL"
+    has_conflicts="true"
+    conflict_list["${conflict_index}"]="$1"
+    conflict_index=$((conflict_index + 1))
+}
+
+function do_action {
+    if ! "${dry_run}"; then
+        "$@"
+    fi
+}
+
+recreate_dir "${old_scripts}"
+
+get_all_scripts_files | while read file; do
+    c="${problem_scripts}/${file}"
+    b="${source_current_scripts}/${file}"
+    a="${old_scripts}/${file}"
+
+    a_exists="true"
+    git show "${old_scripts_version}:${file}" > "${a}" || a_exists="false"
+
+    b_exists="true"
+    [ -f "${b}" ] || b_exists="false"
+
+    c_exists="true"
+    [ -f "${c}" ] || c_exists="false"
+
+    status="OK"
+    message=""
+    if "${b_exists}"; then
+        if "${c_exists}"; then
+            if diff "${b}" "${c}"; then
+                message="'${file}' is not changed"
+            elif "${a_exists}" && diff "${a}" "${b}"; then
+                message="keeping changes of '${file}' in problem"
+            elif "${a_exists}" && diff "${a}" "${c}"; then
+                message="applying changes to '${file}'"
+                do_action cp "${b}" "${c}"
+            else
+                push_conflict "${file}"
+                message="CONFLICT! both problem and script source changed '${file}'"
+            fi
+        else
+            if ! "${a_exists}"; then
+                message="new file '${file}' added"
+                do_action mkdir -p "$(dirname "${c}")"
+                do_action cp "${b}" "${c}"
+            elif diff "${a}" "${b}"; then
+                message="keeping file '${file}' deleted"
+            else
+                push_conflict "${file}"
+                message="CONFLICT! file '${file}' which is deleted in problem has been updated"
+            fi
+        fi
+    else
+        if "${c_exists}"; then
+            if ! "${a_exists}"; then
+                message="keeping extra file '${file}' in problem"
+            elif diff "${a}" "${c}"; then
+                message="deleted file '${file}' because it is deleted in source"
+                do_action rm -f "${c}"
+            else
+                push_conflict "${file}"
+                message="CONFLICT! file '${file}' which is changed in problem has been deleted"
+            fi
+        else
+            errcho "Unreachable code reached!"
+            exit 1
+        fi
+    fi
+
+    errcho -e "${file}:\t[${status}]\t${message}"
+done
+
+echo "$(source_current_scripts_version)" > "${problem_old_scripts_version_file}"
+
+echo
+
+
+if "${has_conflicts}"; then
+    errcho "Please resolve the following conflicts now!"
+    sleep 0.1
+    for file in "${conflict_list[@]}"; do
+        echo "${file}"
+    done
+
+    exit 10
+fi