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

# Generate README.md with download & run commands for .sh and .bat scripts
# This file is intended to be run in CI and locally.

determine_repo_web_base() {
  local origin_url
  origin_url="$(git config --get remote.origin.url || true)"
  if [[ -z "${origin_url}" ]]; then
    echo "Error: could not determine git remote origin URL" >&2
    exit 1
  fi

  local web_base
  if [[ "${origin_url}" =~ ^https?:// ]]; then
    web_base="${origin_url%.git}"
  elif [[ "${origin_url}" =~ ^git@([^:]+):(.+)\.git$ ]]; then
    local host path
    host="${BASH_REMATCH[1]}"
    path="${BASH_REMATCH[2]}"
    web_base="https://${host}/${path}"
  else
    # Fallback: strip trailing .git if present
    web_base="${origin_url%.git}"
  fi

  printf '%s' "${web_base}"
}

determine_branch() {
  # Prefer BRANCH env, fall back to current branch, else main
  if [[ -n "${BRANCH:-}" ]]; then
    printf '%s' "${BRANCH}"
    return
  fi
  local branch
  branch="$(git rev-parse --abbrev-ref HEAD 2>/dev/null || true)"
  if [[ -z "${branch}" || "${branch}" == "HEAD" ]]; then
    branch="main"
  fi
  printf '%s' "${branch}"
}

list_files() {
  # List tracked files matching a glob, excluding scripts/generate_readme.sh
  local pattern="$1"
  if git rev-parse --is-inside-work-tree >/dev/null 2>&1; then
    # Use git to respect .gitignore and include only tracked files
    git ls-files "${pattern}" 2>/dev/null | grep -v '^scripts/generate_readme.sh$' || true
  else
    find . -type f -name "${pattern}" -not -path './scripts/generate_readme.sh' -print | sed 's|^\./||' || true
  fi
}

main() {
  local web_base branch raw_base
  web_base="$(determine_repo_web_base)"
  branch="$(determine_branch)"
  raw_base="${web_base}/raw/branch/${branch}"

  # Collect files
  mapfile -t sh_files < <(list_files '*.sh' | sort)
  mapfile -t bat_files < <(list_files '*.bat' | sort)

  # Begin README content
  {
    echo "# tools"
    echo
    echo "Auto-generated README. Do not edit by hand."
    echo
    echo "This file is regenerated by \`scripts/generate_readme.sh\` on every push."
    echo
    if ((${#sh_files[@]} > 0)); then
      echo "## Shell (.sh)"
      echo
      echo "Run on Linux/macOS using curl:"
      echo
      for f in "${sh_files[@]}"; do
        local name url
        name="$(basename "${f}")"
        url="${raw_base}/${f}"
        echo "### ${name}"
        echo
        echo '```bash'
        echo "curl -fsSL -o ${name} \"${url}\" && chmod +x ${name} && ./\"${name}\""
        echo '```'
        echo
      done
    fi

    if ((${#bat_files[@]} > 0)); then
      echo "## Windows (.bat)"
      echo
      echo "Run from PowerShell:"
      echo
      for f in "${bat_files[@]}"; do
        local name url
        name="$(basename "${f}")"
        url="${raw_base}/${f}"
        echo "### ${name}"
        echo
        echo '```powershell'
        echo '$dest = Join-Path $env:TEMP "'"${name}"'";'
        echo 'Invoke-WebRequest -Uri '"\"${url}\""' -OutFile $dest;'
        echo '& $dest'
        echo '```'
        echo
      done
    fi

    echo "---"
    echo
    echo "Generated from repo: \`${web_base}\` on branch \`${branch}\`."
  } > README.md
}

main "$@"