# 1. 讓腳本可執行：
# chmod +x utils/leetcode_helper.sh
# 2. 建立新題目：
# ./utils/leetcode_helper.sh problem 1 two-sum Easy
# ./utils/leetcode_helper.sh problem 3000 maximum-area-rectangle Medium
# 3. 建立月度日誌：
# ./utils/leetcode_helper.sh log 2025-09
# 4. 更新README：
# ./utils/leetcode_helper.sh readme

#!/bin/bash
set -euo pipefail

# 路徑設定
SCRIPT_DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
ROOT_DIR=$(cd "$SCRIPT_DIR/.." && pwd)
TEMPLATES_DIR="$ROOT_DIR/templates"

# kebab-case -> Title Case（two-sum -> Two Sum）
to_title_case() {
  local s="${1//-/ }"
  echo "$s" | awk '{for(i=1;i<=NF;i++){ $i=toupper(substr($i,1,1)) substr($i,2) } print }'
}

# 渲染模板到目的檔
# 變數：{{NUMBER}}, {{NUMBER_PAD}}, {{NAME_SLUG}}, {{NAME_TITLE}}, {{DIFFICULTY}}, {{DATE}}, {{YEAR_MONTH}}
render_template() {
  local src="$1"; shift
  local dest="$1"; shift

  local number="${1:-}"; shift || true
  local number_pad="${1:-}"; shift || true
  local name_slug="${1:-}"; shift || true
  local name_title="${1:-}"; shift || true
  local difficulty="${1:-}"; shift || true
  local today="${1:-}"; shift || true
  local year_month="${1:-}"; shift || true

  mkdir -p "$(dirname "$dest")"
  sed -e "s/{{NUMBER}}/${number}/g" \
      -e "s/{{NUMBER_PAD}}/${number_pad}/g" \
      -e "s/{{NAME_SLUG}}/${name_slug}/g" \
      -e "s/{{NAME_TITLE}}/${name_title}/g" \
      -e "s/{{DIFFICULTY}}/${difficulty}/g" \
      -e "s/{{DATE}}/${today}/g" \
      -e "s/{{YEAR_MONTH}}/${year_month}/g" \
      "$src" > "$dest"
}

# 建立測試檔案（來自 templates/problem/test/*）
create_test_files() {
  local problem_dir="$1"; local number="$2"; local name_slug="$3"; local difficulty="$4"
  local number_pad=$(printf "%04d" "$number")
  local name_title=$(to_title_case "$name_slug")
  local today=$(date +%Y-%m-%d)
  local year_month=$(date +%Y-%m)

  render_template "$TEMPLATES_DIR/problem/test/SolutionTests.cs.tmpl" \
    "$problem_dir/test/SolutionTests.cs" \
    "$number" "$number_pad" "$name_slug" "$name_title" "$difficulty" "$today" "$year_month"

  render_template "$TEMPLATES_DIR/problem/test/TestProject.csproj.tmpl" \
    "$problem_dir/test/TestProject.csproj" \
    "$number" "$number_pad" "$name_slug" "$name_title" "$difficulty" "$today" "$year_month"

  render_template "$TEMPLATES_DIR/problem/test/main_test.go.tmpl" \
    "$problem_dir/test/main_test.go" \
    "$number" "$number_pad" "$name_slug" "$name_title" "$difficulty" "$today" "$year_month"

  render_template "$TEMPLATES_DIR/problem/test/edge_cases.md.tmpl" \
    "$problem_dir/test/edge_cases.md" \
    "$number" "$number_pad" "$name_slug" "$name_title" "$difficulty" "$today" "$year_month"

  render_template "$TEMPLATES_DIR/problem/test/input1.txt.tmpl" "$problem_dir/test/input1.txt" \
    "$number" "$number_pad" "$name_slug" "$name_title" "$difficulty" "$today" "$year_month"
  render_template "$TEMPLATES_DIR/problem/test/output1.txt.tmpl" "$problem_dir/test/output1.txt" \
    "$number" "$number_pad" "$name_slug" "$name_title" "$difficulty" "$today" "$year_month"
  render_template "$TEMPLATES_DIR/problem/test/input2.txt.tmpl" "$problem_dir/test/input2.txt" \
    "$number" "$number_pad" "$name_slug" "$name_title" "$difficulty" "$today" "$year_month"
  render_template "$TEMPLATES_DIR/problem/test/output2.txt.tmpl" "$problem_dir/test/output2.txt" \
    "$number" "$number_pad" "$name_slug" "$name_title" "$difficulty" "$today" "$year_month"

  render_template "$TEMPLATES_DIR/problem/test/run_tests.sh.tmpl" \
    "$problem_dir/test/run_tests.sh" \
    "$number" "$number_pad" "$name_slug" "$name_title" "$difficulty" "$today" "$year_month"
  chmod +x "$problem_dir/test/run_tests.sh"
}

# 建立新題目
create_problem() {
  local number="$1"; local name_slug="$2"; local difficulty="$3"
  if [[ -z "${number:-}" || -z "${name_slug:-}" || -z "${difficulty:-}" ]]; then
    echo "使用方法: $0 problem <題號> <題目名稱-kebab> <難度>"; exit 1
  fi

  local number_pad=$(printf "%04d" "$number")
  local folder_name="${number_pad}-${name_slug}"
  local problem_dir="$ROOT_DIR/problems/${folder_name}"
  local name_title=$(to_title_case "$name_slug")
  local today=$(date +%Y-%m-%d)
  local year_month=$(date +%Y-%m)

  mkdir -p "$problem_dir/csharp" "$problem_dir/go" "$problem_dir/test"

  # README
  render_template "$TEMPLATES_DIR/problem/README.md.tmpl" \
    "$problem_dir/README.md" \
    "$number" "$number_pad" "$name_slug" "$name_title" "$difficulty" "$today" "$year_month"

  # C#
  render_template "$TEMPLATES_DIR/problem/csharp/Program.cs.tmpl" \
    "$problem_dir/csharp/Program.cs" \
    "$number" "$number_pad" "$name_slug" "$name_title" "$difficulty" "$today" "$year_month"
  render_template "$TEMPLATES_DIR/problem/csharp/csharp.csproj.tmpl" \
    "$problem_dir/csharp/csharp.csproj" \
    "$number" "$number_pad" "$name_slug" "$name_title" "$difficulty" "$today" "$year_month"

  # Go
  render_template "$TEMPLATES_DIR/problem/go/main.go.tmpl" \
    "$problem_dir/go/main.go" \
    "$number" "$number_pad" "$name_slug" "$name_title" "$difficulty" "$today" "$year_month"
  (cd "$problem_dir/go" && go mod init "leetcode-$number" >/dev/null 2>&1 || true)

  # Tests
  create_test_files "$problem_dir" "$number" "$name_slug" "$difficulty"

  echo "✅ 已建立題目: $problem_dir"
  echo "C#:   cd problems/${folder_name}/csharp && dotnet run"
  echo "Go:   cd problems/${folder_name}/go && go run main.go"
  echo "測試: cd problems/${folder_name}/test && ./run_tests.sh"
}

# 更新主 README（目前僅統計列印）
update_readme() {
  echo "🔄 更新主 README 統計..."
  local total_problems=$(find "$ROOT_DIR/problems" -maxdepth 1 -type d | wc -l)
  total_problems=$((total_problems - 1))
  local completed_problems=$(find "$ROOT_DIR/problems" -name "README.md" -exec grep -l "✅" {} \; | wc -l)
  echo "📊 題目總數: $total_problems，標記完成: $completed_problems"
}

# 建立月度日誌（由模板 logs-template.md.tmpl 渲染）
create_monthly_log() {
  local year_month="${1:-}"
  if [[ -z "$year_month" ]]; then year_month=$(date +%Y-%m); fi

  local dest="$ROOT_DIR/logs/${year_month}.md"
  if [[ -f "$dest" ]]; then echo "⚠️  已存在: $dest"; return 1; fi
  mkdir -p "$ROOT_DIR/logs"
  render_template "$TEMPLATES_DIR/logs-template.md.tmpl" "$dest" "" "" "" "" "" "" "$year_month"
  echo "✅ 已建立月度日誌: $dest"
}

# 入口
case "${1:-}" in
  problem)
    create_problem "${2:-}" "${3:-}" "${4:-}" ;;
  readme)
    update_readme ;;
  log)
    create_monthly_log "${2:-}" ;;
  *)
    echo "LeetCode Practice Helper"
    echo "使用："
    echo "  $0 problem <題號> <題目名稱-kebab> <難度>"
    echo "  $0 readme"
    echo "  $0 log [YYYY-MM]"
    ;;
esac