#!/usr/bin/env bash
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
RECONCILER="${SCRIPT_DIR}/local-proxy-reconcile.sh"
ORIGINAL_PATH="$PATH"

fail() {
  printf 'FAIL: %s\n' "$1" >&2
  exit 1
}

assert_equals() {
  local expected="$1"
  local actual="$2"
  local message="$3"

  if [ "$expected" != "$actual" ]; then
    fail "${message}: expected=${expected}, actual=${actual}"
  fi
}

new_fixture() {
  FIXTURE_ROOT="$(mktemp -d)"
  export FIXTURE_ROOT
  export FAKE_STATE_DIR="${FIXTURE_ROOT}/state"
  export PROXY_ROOT="${FIXTURE_ROOT}/proxy"
  export PROXY_RECONCILE_LOCK_FILE="${FIXTURE_ROOT}/reconcile.lock"
  export NGINX_BIN="${FIXTURE_ROOT}/bin/nginx"
  export CONTAINER_NAME="material"
  export PROXY_SERVICE="material-local-proxy.service"
  export PORT="4320"
  export PATH="${FIXTURE_ROOT}/bin:${ORIGINAL_PATH}"
  mkdir -p "$FAKE_STATE_DIR" "$PROXY_ROOT" "${FIXTURE_ROOT}/bin"

  cat > "${FIXTURE_ROOT}/bin/docker" <<'EOF'
#!/usr/bin/env bash
set -euo pipefail
template="$3"
name="$4"
if [[ "$template" == *'.State.Running'* ]]; then
  cat "${FAKE_STATE_DIR}/${name}.running" 2>/dev/null || printf 'false\n'
else
  cat "${FAKE_STATE_DIR}/${name}.ip" 2>/dev/null || true
fi
EOF

  cat > "${FIXTURE_ROOT}/bin/curl" <<'EOF'
#!/usr/bin/env bash
set -euo pipefail
url="${!#}"
if [[ "$url" == http://127.0.0.1:* ]]; then
  if [ -f "${FAKE_STATE_DIR}/entry.connect-fail" ]; then
    exit 7
  fi
  if printf '%s\n' "$@" | grep -qx -- '-D'; then
    printf 'HTTP/1.1 %s Test\r\n' "$([ -f "${FAKE_STATE_DIR}/entry.ok" ] && printf '200' || printf '502')"
    if [ -s "${FAKE_STATE_DIR}/runtime.target" ]; then
      printf 'X-Material-Proxy-Target: %s\r\n' "$(cat "${FAKE_STATE_DIR}/runtime.target")"
    fi
    printf '\r\n'
    exit 0
  fi
  [ -f "${FAKE_STATE_DIR}/entry.ok" ]
  exit
fi
ip="${url#http://}"
ip="${ip%%:*}"
[ -f "${FAKE_STATE_DIR}/healthy.${ip}" ]
EOF

  cat > "${FIXTURE_ROOT}/bin/systemctl" <<'EOF'
#!/usr/bin/env bash
set -euo pipefail
case "$1" in
  is-active) exit 0 ;;
  reload|start)
    printf '%s\n' "$1" >> "${FAKE_STATE_DIR}/systemctl.log"
    target="$(sed -nE 's/^[[:space:]]*add_header X-Material-Proxy-Target ([^;[:space:]]+) always;.*/\1/p' "${PROXY_ROOT}/nginx.conf" | tail -n 1)"
    if [ -n "$target" ]; then
      printf '%s\n' "$target" > "${FAKE_STATE_DIR}/runtime.target"
    fi
    if [ "${FAKE_RECOVER_ON_RELOAD:-0}" = "1" ]; then
      rm -f "${FAKE_STATE_DIR}/entry.connect-fail"
      touch "${FAKE_STATE_DIR}/entry.ok"
    fi
    count=0
    if [ -f "${FAKE_STATE_DIR}/reload.count" ]; then
      count="$(cat "${FAKE_STATE_DIR}/reload.count")"
    fi
    count=$((count + 1))
    printf '%s\n' "$count" > "${FAKE_STATE_DIR}/reload.count"
    if [ "${FAKE_RELOAD_FAIL_FIRST:-0}" = "1" ] && [ "$count" -eq 1 ]; then
      exit 1
    fi
    ;;
esac
EOF

  cat > "${FIXTURE_ROOT}/bin/nginx" <<'EOF'
#!/usr/bin/env bash
exit 0
EOF

  cat > "${FIXTURE_ROOT}/bin/sleep" <<'EOF'
#!/usr/bin/env bash
exit 0
EOF

  cat > "${FIXTURE_ROOT}/bin/flock" <<'EOF'
#!/usr/bin/env bash
[ "${FAKE_FLOCK_FAIL:-0}" = "1" ] && exit 1
exit 0
EOF

  chmod +x "${FIXTURE_ROOT}/bin/"*
}

write_proxy_config() {
  local ip="$1"
  local target="${2:-}"
  cat > "${PROXY_ROOT}/nginx.conf" <<EOF
events {}
http {
  upstream app_backend {
    server ${ip}:3000 max_fails=3 fail_timeout=5s;
  }
  server {
    location / {
$(if [ -n "$target" ]; then printf '      proxy_hide_header X-Material-Proxy-Target;\n      add_header X-Material-Proxy-Target %s always;\n' "$target"; fi)
    }
  }
}
EOF
}

set_container() {
  local name="$1"
  local ip="$2"
  local healthy="$3"

  printf 'true\n' > "${FAKE_STATE_DIR}/${name}.running"
  printf '%s\n' "$ip" > "${FAKE_STATE_DIR}/${name}.ip"
  if [ "$healthy" = "1" ]; then
    touch "${FAKE_STATE_DIR}/healthy.${ip}"
  fi
}

cleanup_fixture() {
  PATH="$ORIGINAL_PATH"
  unset FAKE_RECOVER_ON_RELOAD || true
  unset FAKE_RELOAD_FAIL_FIRST || true
  unset FAKE_FLOCK_FAIL || true
  rm -rf "$FIXTURE_ROOT"
}

test_healthy_entry_wins_over_stale_state() {
  new_fixture
  set_container material-blue 10.0.0.2 1
  set_container material-green 10.0.0.3 1
  printf 'material-blue\n' > "${PROXY_ROOT}/current-container"
  write_proxy_config 10.0.0.3 material-green
  printf 'material-green\n' > "${FAKE_STATE_DIR}/runtime.target"
  touch "${FAKE_STATE_DIR}/entry.ok"

  "$RECONCILER"

  assert_equals "material-green" "$(tr -d '\r\n' < "${PROXY_ROOT}/current-container")" "healthy proxy target should repair stale state"
  [ ! -f "${FAKE_STATE_DIR}/systemctl.log" ] || fail "healthy entry must not be reloaded"
  grep -q 'server 10.0.0.3:3000 ' "${PROXY_ROOT}/nginx.conf" || fail "healthy proxy target must not be changed"
  cleanup_fixture
}

test_disk_config_does_not_override_verified_runtime() {
  new_fixture
  set_container material-blue 10.0.0.2 1
  set_container material-green 10.0.0.3 1
  printf 'material-blue\n' > "${PROXY_ROOT}/current-container"
  write_proxy_config 10.0.0.3 material-green
  printf 'material-blue\n' > "${FAKE_STATE_DIR}/runtime.target"
  touch "${FAKE_STATE_DIR}/entry.ok"

  "$RECONCILER"

  assert_equals "material-blue" "$(tr -d '\r\n' < "${PROXY_ROOT}/current-container")" "verified runtime should win over an un-reloaded disk config"
  grep -q 'server 10.0.0.2:3000 ' "${PROXY_ROOT}/nginx.conf" || fail "disk config should be restored to the verified runtime target"
  assert_equals "material-blue" "$(tr -d '\r\n' < "${FAKE_STATE_DIR}/runtime.target")" "reload should keep the verified runtime target"
  cleanup_fixture
}

test_markerless_healthy_conflict_fails_closed() {
  new_fixture
  set_container material-blue 10.0.0.2 1
  set_container material-green 10.0.0.3 1
  printf 'material-blue\n' > "${PROXY_ROOT}/current-container"
  write_proxy_config 10.0.0.3 material-green
  touch "${FAKE_STATE_DIR}/entry.ok"

  if "$RECONCILER"; then
    fail "markerless healthy state/config conflict should fail closed"
  fi

  assert_equals "material-blue" "$(tr -d '\r\n' < "${PROXY_ROOT}/current-container")" "ambiguous markerless state must remain untouched"
  grep -q 'server 10.0.0.3:3000 ' "${PROXY_ROOT}/nginx.conf" || fail "ambiguous markerless config must remain untouched"
  [ ! -f "${FAKE_STATE_DIR}/systemctl.log" ] || fail "ambiguous markerless state must not reload the proxy"
  cleanup_fixture
}

test_broken_entry_prefers_configured_target_over_stale_state() {
  new_fixture
  set_container material-blue 10.0.0.2 1
  set_container material-green 10.0.0.3 1
  printf 'material-blue\n' > "${PROXY_ROOT}/current-container"
  write_proxy_config 10.0.0.3 material-green
  export FAKE_RECOVER_ON_RELOAD=1

  "$RECONCILER"

  assert_equals "material-green" "$(tr -d '\r\n' < "${PROXY_ROOT}/current-container")" "broken entry should prefer the configured healthy target"
  assert_equals "material-green" "$(tr -d '\r\n' < "${FAKE_STATE_DIR}/runtime.target")" "configured target should become the verified runtime"
  cleanup_fixture
}

test_reload_error_with_verified_target_succeeds() {
  new_fixture
  set_container material-blue 10.0.0.2 1
  set_container material-green 10.0.0.3 1
  printf 'material-blue\n' > "${PROXY_ROOT}/current-container"
  write_proxy_config 10.0.0.2 material-blue
  printf 'material-blue\n' > "${FAKE_STATE_DIR}/runtime.target"
  rm -f "${FAKE_STATE_DIR}/entry.ok"
  # Make the disk target drift while the recorded state remains blue.
  write_proxy_config 10.0.0.3 material-green
  export FAKE_RECOVER_ON_RELOAD=1
  export FAKE_RELOAD_FAIL_FIRST=1

  "$RECONCILER"

  assert_equals "material-blue" "$(tr -d '\r\n' < "${PROXY_ROOT}/current-container")" "verified runtime should remain authoritative"
  assert_equals "material-blue" "$(tr -d '\r\n' < "${FAKE_STATE_DIR}/runtime.target")" "verified target should be accepted despite the command status"
  cleanup_fixture
}

test_deployment_lock_blocks_reconciliation() {
  new_fixture
  set_container material-green 10.0.0.3 1
  printf 'material-blue\n' > "${PROXY_ROOT}/current-container"
  write_proxy_config 10.0.0.4
  export FAKE_FLOCK_FAIL=1

  "$RECONCILER"

  grep -q 'server 10.0.0.4:3000 ' "${PROXY_ROOT}/nginx.conf" || fail "deployment lock must leave proxy configuration untouched"
  [ ! -f "${FAKE_STATE_DIR}/systemctl.log" ] || fail "reconciler must not reload while deployment lock is held"
  cleanup_fixture
}

test_connection_failure_recovers_to_configured_target() {
  new_fixture
  set_container material-green 10.0.0.3 1
  printf 'material-green\n' > "${PROXY_ROOT}/current-container"
  write_proxy_config 10.0.0.3 material-green
  touch "${FAKE_STATE_DIR}/entry.connect-fail"
  export FAKE_RECOVER_ON_RELOAD=1

  "$RECONCILER"

  assert_equals "material-green" "$(tr -d '\r\n' < "${PROXY_ROOT}/current-container")" "connection failure should recover to the configured healthy target"
  assert_equals "material-green" "$(tr -d '\r\n' < "${FAKE_STATE_DIR}/runtime.target")" "recovered target should be verified at runtime"
  grep -q '^reload$' "${FAKE_STATE_DIR}/systemctl.log" || fail "connection failure recovery should reload the proxy"
  cleanup_fixture
}

test_single_healthy_container_repairs_broken_proxy() {
  new_fixture
  set_container material-green 10.0.0.3 1
  printf 'material-blue\n' > "${PROXY_ROOT}/current-container"
  write_proxy_config 10.0.0.4
  export FAKE_RECOVER_ON_RELOAD=1

  "$RECONCILER"

  assert_equals "material-green" "$(tr -d '\r\n' < "${PROXY_ROOT}/current-container")" "recovery should persist the selected container"
  grep -q 'server 10.0.0.3:3000 ' "${PROXY_ROOT}/nginx.conf" || fail "recovery should update the upstream address"
  grep -q '^reload$' "${FAKE_STATE_DIR}/systemctl.log" || fail "recovery should reload the proxy"
  cleanup_fixture
}

test_ambiguous_containers_fail_closed() {
  new_fixture
  set_container material-blue 10.0.0.2 1
  set_container material-green 10.0.0.3 1
  printf 'invalid-container\n' > "${PROXY_ROOT}/current-container"
  write_proxy_config 10.0.0.4

  if "$RECONCILER"; then
    fail "ambiguous healthy containers should not be switched automatically"
  fi

  grep -q 'server 10.0.0.4:3000 ' "${PROXY_ROOT}/nginx.conf" || fail "ambiguous state must leave proxy configuration untouched"
  [ ! -f "${FAKE_STATE_DIR}/systemctl.log" ] || fail "ambiguous state must not reload the proxy"
  cleanup_fixture
}

trap 'if [ -n "${FIXTURE_ROOT:-}" ] && [ -d "${FIXTURE_ROOT}" ]; then rm -rf "$FIXTURE_ROOT"; fi' EXIT

test_healthy_entry_wins_over_stale_state
test_single_healthy_container_repairs_broken_proxy
test_ambiguous_containers_fail_closed
test_disk_config_does_not_override_verified_runtime
test_markerless_healthy_conflict_fails_closed
test_broken_entry_prefers_configured_target_over_stale_state
test_reload_error_with_verified_target_succeeds
test_deployment_lock_blocks_reconciliation
test_connection_failure_recovers_to_configured_target

printf 'PASS: local proxy reconciler scenarios\n'