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

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
REPO_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
VERIFY_SCRIPT="$REPO_ROOT/scripts/verify_asm.sh"
BUILD_DIR="$REPO_ROOT/build_lab3"
RUN_ROOT="$REPO_ROOT/output/logs/lab3"
LAST_RUN_FILE="$RUN_ROOT/last_run.txt"
LAST_FAILED_FILE="$RUN_ROOT/last_failed.txt"
RUN_NAME="lab3_$(date +%Y%m%d_%H%M%S)"
RUN_DIR="$RUN_ROOT/$RUN_NAME"
WHOLE_LOG="$RUN_DIR/whole.log"
FAIL_DIR="$RUN_DIR/failures"
LEGACY_SAVE_ASM=false
FAILED_ONLY=false
FALLBACK_TO_FULL=false

RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m'

TEST_DIRS=()
TEST_FILES=()
while [[ $# -gt 0 ]]; do
  case "$1" in
    --save-asm)
      LEGACY_SAVE_ASM=true
      ;;
    --failed-only)
      FAILED_ONLY=true
      ;;
    *)
      if [[ -f "$1" ]]; then
        TEST_FILES+=("$1")
      else
        TEST_DIRS+=("$1")
      fi
      ;;
  esac
  shift
done

mkdir -p "$RUN_DIR"
: > "$WHOLE_LOG"
printf '%s\n' "$RUN_DIR" > "$LAST_RUN_FILE"

log_plain() {
  printf '%s\n' "$*"
  printf '%s\n' "$*" >> "$WHOLE_LOG"
}

log_color() {
  local color="$1"
  shift
  local message="$*"
  printf '%b%s%b\n' "$color" "$message" "$NC"
  printf '%s\n' "$message" >> "$WHOLE_LOG"
}

append_file_to_whole_log() {
  local title="$1"
  local file="$2"
  {
    printf '\n===== %s =====\n' "$title"
    cat "$file"
    printf '\n'
  } >> "$WHOLE_LOG"
}

cleanup_tmp_dir() {
  local dir="$1"
  if [[ -d "$dir" ]]; then
    rm -rf "$dir"
  fi
}

discover_default_test_dirs() {
  local roots=(
    "$REPO_ROOT/test/test_case"
    "$REPO_ROOT/test/class_test_case"
  )
  local root
  for root in "${roots[@]}"; do
    [[ -d "$root" ]] || continue
    find "$root" -mindepth 1 -maxdepth 1 -type d -print0
  done | sort -z
}

prune_empty_run_dirs() {
  if [[ -d "$RUN_DIR/.tmp" ]]; then
    rmdir "$RUN_DIR/.tmp" 2>/dev/null || true
  fi
  if [[ -d "$FAIL_DIR" ]]; then
    rmdir "$FAIL_DIR" 2>/dev/null || true
  fi
}

now_ns() {
  date +%s%N
}

format_duration_ns() {
  local ns="$1"
  local sec=$((ns / 1000000000))
  local ms=$(((ns % 1000000000) / 1000000))
  printf '%d.%03ds' "$sec" "$ms"
}

is_transient_io_failure() {
  local log_file="$1"
  [[ -f "$log_file" ]] || return 1
  grep -Eq \
    'Permission denied|Text file busy|Device or resource busy|Stale file handle|Input/output error|Resource temporarily unavailable|Read-only file system' \
    "$log_file"
}

test_one() {
  local sy_file="$1"
  local rel="$2"
  local safe_name="${rel//\//_}"
  local case_key="${safe_name%.sy}"
  local tmp_dir="$RUN_DIR/.tmp/$case_key"
  local fail_case_dir="$FAIL_DIR/$case_key"
  local case_log="$tmp_dir/error.log"
  local attempt=1

  cleanup_tmp_dir "$fail_case_dir"

  while true; do
    cleanup_tmp_dir "$tmp_dir"
    mkdir -p "$tmp_dir"

    if "$VERIFY_SCRIPT" "$sy_file" "$tmp_dir" --run > "$case_log" 2>&1; then
      cleanup_tmp_dir "$tmp_dir"
      return 0
    fi

    if [[ $attempt -eq 1 ]] && is_transient_io_failure "$case_log"; then
      log_color "$YELLOW" "RETRY $rel (transient I/O failure)"
      attempt=$((attempt + 1))
      continue
    fi

    break
  done

  mkdir -p "$FAIL_DIR"
  mv "$tmp_dir" "$fail_case_dir"
  append_file_to_whole_log "$rel" "$fail_case_dir/error.log"
  return 1
}

run_case() {
  local sy_file="$1"
  local rel
  local case_start_ns
  local case_end_ns
  local case_elapsed_ns
  rel="$(realpath --relative-to="$REPO_ROOT" "$sy_file")"
  case_start_ns=$(now_ns)

  if test_one "$sy_file" "$rel"; then
    case_end_ns=$(now_ns)
    case_elapsed_ns=$((case_end_ns - case_start_ns))
    log_color "$GREEN" "PASS  $rel  [$(format_duration_ns "$case_elapsed_ns")]"
    PASS=$((PASS + 1))
  else
    case_end_ns=$(now_ns)
    case_elapsed_ns=$((case_end_ns - case_start_ns))
    log_color "$RED" "FAIL  $rel  [$(format_duration_ns "$case_elapsed_ns")]"
    FAIL=$((FAIL + 1))
    FAIL_LIST+=("$rel")
  fi
}

TOTAL_START_NS=$(now_ns)

if [[ "$FAILED_ONLY" == true ]]; then
  if [[ -f "$LAST_FAILED_FILE" ]]; then
    while IFS= read -r sy_file; do
      [[ -n "$sy_file" ]] || continue
      [[ -f "$sy_file" ]] || continue
      TEST_FILES+=("$sy_file")
    done < "$LAST_FAILED_FILE"
  fi

  if [[ ${#TEST_FILES[@]} -eq 0 ]]; then
    FALLBACK_TO_FULL=true
    FAILED_ONLY=false
  fi
fi

if [[ "$FAILED_ONLY" == false && ${#TEST_DIRS[@]} -eq 0 && ${#TEST_FILES[@]} -eq 0 ]]; then
  while IFS= read -r -d '' test_dir; do
    TEST_DIRS+=("$test_dir")
  done < <(discover_default_test_dirs)
fi

log_plain "Run directory: $RUN_DIR"
log_plain "Whole log: $WHOLE_LOG"
if [[ "$LEGACY_SAVE_ASM" == true ]]; then
  log_color "$YELLOW" "Warning: --save-asm is deprecated; successful case artifacts will still be deleted."
fi
if [[ "$FAILED_ONLY" == true ]]; then
  log_plain "Mode: rerun cached failed cases only"
fi
if [[ "$FALLBACK_TO_FULL" == true ]]; then
  log_color "$YELLOW" "No cached failed cases found, fallback to full suite."
fi

if [[ ! -f "$VERIFY_SCRIPT" ]]; then
  log_color "$RED" "missing verify script: $VERIFY_SCRIPT"
  exit 1
fi

for tool in llc aarch64-linux-gnu-gcc qemu-aarch64; do
  if ! command -v "$tool" >/dev/null 2>&1; then
    log_color "$RED" "missing required tool: $tool"
    exit 1
  fi
done

log_plain "==> [1/2] Configure and build compiler"
BUILD_START_NS=$(now_ns)
if ! cmake -S "$REPO_ROOT" -B "$BUILD_DIR" >> "$WHOLE_LOG" 2>&1; then
  log_color "$RED" "CMake configure failed. See $WHOLE_LOG"
  exit 1
fi
if ! cmake --build "$BUILD_DIR" -j "$(nproc)" >> "$WHOLE_LOG" 2>&1; then
  log_color "$RED" "Compiler build failed. See $WHOLE_LOG"
  exit 1
fi
BUILD_END_NS=$(now_ns)
BUILD_ELAPSED_NS=$((BUILD_END_NS - BUILD_START_NS))

log_plain "==> [2/2] Run ASM validation suite"
VALIDATION_START_NS=$(now_ns)
PASS=0
FAIL=0
FAIL_LIST=()

if [[ "$FAILED_ONLY" == true ]]; then
  for sy_file in "${TEST_FILES[@]}"; do
    run_case "$sy_file"
  done
else
  for sy_file in "${TEST_FILES[@]}"; do
    run_case "$sy_file"
  done

  for test_dir in "${TEST_DIRS[@]}"; do
    if [[ ! -d "$test_dir" ]]; then
      log_color "$YELLOW" "skip missing dir: $test_dir"
      continue
    fi

    while IFS= read -r -d '' sy_file; do
      run_case "$sy_file"
    done < <(find "$test_dir" -maxdepth 1 -type f -name '*.sy' -print0 | sort -z)
  done
fi

rm -f "$LAST_FAILED_FILE"
if [[ ${#FAIL_LIST[@]} -gt 0 ]]; then
  for f in "${FAIL_LIST[@]}"; do
    printf '%s/%s\n' "$REPO_ROOT" "$f" >> "$LAST_FAILED_FILE"
  done
fi

prune_empty_run_dirs
VALIDATION_END_NS=$(now_ns)
VALIDATION_ELAPSED_NS=$((VALIDATION_END_NS - VALIDATION_START_NS))
TOTAL_END_NS=$(now_ns)
TOTAL_ELAPSED_NS=$((TOTAL_END_NS - TOTAL_START_NS))

log_plain ""
log_plain "summary: ${PASS} PASS / ${FAIL} FAIL / total $((PASS + FAIL))"
log_plain "build elapsed: $(format_duration_ns "$BUILD_ELAPSED_NS")"
log_plain "validation elapsed: $(format_duration_ns "$VALIDATION_ELAPSED_NS")"
log_plain "total elapsed: $(format_duration_ns "$TOTAL_ELAPSED_NS")"
if [[ ${#FAIL_LIST[@]} -gt 0 ]]; then
  log_plain "failed cases:"
  for f in "${FAIL_LIST[@]}"; do
    safe_name="${f//\//_}"
    log_plain "- $f"
    log_plain "  artifacts: $FAIL_DIR/${safe_name%.sy}"
  done
else
  log_plain "all successful case artifacts have been deleted automatically."
fi
log_plain "whole log saved to: $WHOLE_LOG"

[[ $FAIL -eq 0 ]]