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

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
# shellcheck source=scripts/github/_gh_env.sh
source "$SCRIPT_DIR/_gh_env.sh"

METHOD="GET"
GRAPHQL=0
REQUEST_PATH=""
REQUEST_DATA=""
REQUEST_DATA_FILE=""
PRINT_HEADERS=0
HOST_OVERRIDE=""
declare -a EXTRA_HEADERS=()

usage() {
  cat <<'EOF'
Usage:
  bash scripts/github/github_api.sh [options] <rest-path>
  bash scripts/github/github_api.sh --graphql --data '{"query":"query { viewer { login } }"}'

Options:
  --method METHOD       HTTP method, default GET
  --graphql             Call the GraphQL endpoint instead of REST
  --host HOST           Override GH_HOST / GitHub Enterprise host
  --data JSON           Inline JSON request body
  --data-file FILE      Read JSON request body from file
  --header VALUE        Additional header, repeatable
  --include-headers     Print response headers to stderr
  -h, --help            Show help

Environment:
  GH_TOKEN / GITHUB_TOKEN         Required for authentication
  GH_API_CONNECT_TIMEOUT_SEC      Default 10
  GH_API_MAX_TIME_SEC             Default 60
  GH_API_RETRY_MAX_ATTEMPTS       Default 5
  GH_API_RETRY_BASE_DELAY_SEC     Default 2
  GH_API_RETRY_MAX_DELAY_SEC      Default 20
EOF
}

fail() {
  echo "[错误] $1" >&2
  exit 1
}

parse_args() {
  while [[ $# -gt 0 ]]; do
    case "$1" in
      --method)
        METHOD="${2:?missing value for --method}"
        shift 2
        ;;
      --graphql)
        GRAPHQL=1
        shift
        ;;
      --host)
        HOST_OVERRIDE="${2:?missing value for --host}"
        shift 2
        ;;
      --data)
        REQUEST_DATA="${2:?missing value for --data}"
        shift 2
        ;;
      --data-file)
        REQUEST_DATA_FILE="${2:?missing value for --data-file}"
        shift 2
        ;;
      --header)
        EXTRA_HEADERS+=("${2:?missing value for --header}")
        shift 2
        ;;
      --include-headers)
        PRINT_HEADERS=1
        shift
        ;;
      -h|--help)
        usage
        exit 0
        ;;
      --)
        shift
        break
        ;;
      -*)
        fail "未知参数: $1"
        ;;
      *)
        if [[ -n "$REQUEST_PATH" ]]; then
          fail "REST 路径只能提供一个"
        fi
        REQUEST_PATH="$1"
        shift
        ;;
    esac
  done

  if [[ -n "$REQUEST_DATA" && -n "$REQUEST_DATA_FILE" ]]; then
    fail "--data 与 --data-file 只能使用一个"
  fi

  if [[ "$METHOD" == "GET" && ( -n "$REQUEST_DATA" || -n "$REQUEST_DATA_FILE" ) ]]; then
    METHOD="POST"
  fi

  if [[ "$GRAPHQL" -eq 1 && -z "$REQUEST_DATA" && -z "$REQUEST_DATA_FILE" ]]; then
    fail "GraphQL 调用必须提供 --data 或 --data-file"
  fi

  if [[ "$GRAPHQL" -eq 0 && -z "$REQUEST_PATH" ]]; then
    fail "REST 调用必须提供路径，例如 repos/OWNER/REPO/issues"
  fi
}

normalize_rest_url() {
  local path="$1"
  if [[ "$path" =~ ^https?:// ]]; then
    printf '%s\n' "$path"
    return 0
  fi

  path="${path#/}"
  printf '%s/%s\n' "$(gh_env_rest_api_base_url "$HOST_OVERRIDE")" "$path"
}

resolve_request_url() {
  if [[ "$GRAPHQL" -eq 1 ]]; then
    gh_env_graphql_api_url "$HOST_OVERRIDE"
    return 0
  fi

  normalize_rest_url "$REQUEST_PATH"
}

retryable_http_code() {
  case "${1:-0}" in
    408|429|500|502|503|504)
      return 0
      ;;
  esac
  return 1
}

retryable_curl_rc() {
  case "${1:-0}" in
    6|7|18|28|35|52|55|56)
      return 0
      ;;
  esac
  return 1
}

extract_retry_after() {
  local header_file="$1"
  awk 'BEGIN{IGNORECASE=1} /^retry-after:/ {gsub("\r","",$2); print $2; exit}' "$header_file"
}

body_summary() {
  local body_file="$1"
  local summary
  summary="$(tr '\n' ' ' <"$body_file" | sed 's/[[:space:]]\+/ /g; s/^ //; s/ $//')"
  if [[ -z "$summary" ]]; then
    summary="empty response body"
  fi
  printf '%s' "$summary"
}

perform_request() {
  gh_env_prepare
  gh_env_require_token

  local connect_timeout="${GH_API_CONNECT_TIMEOUT_SEC:-10}"
  local max_time="${GH_API_MAX_TIME_SEC:-60}"
  local max_attempts="${GH_API_RETRY_MAX_ATTEMPTS:-5}"
  local base_delay="${GH_API_RETRY_BASE_DELAY_SEC:-2}"
  local max_delay="${GH_API_RETRY_MAX_DELAY_SEC:-20}"
  local attempt=1
  local delay="$base_delay"
  local url=""
  url="$(resolve_request_url)"

  local header_file=""
  local body_file=""
  local stderr_file=""
  header_file="$(mktemp)"
  body_file="$(mktemp)"
  stderr_file="$(mktemp)"

  local curl_rc=0
  local http_code=""
  local retry_after=""
  local summary=""
  local data_args=()
  local -a curl_header_args=()

  if [[ -n "$REQUEST_DATA" ]]; then
    data_args+=(--data "$REQUEST_DATA")
  elif [[ -n "$REQUEST_DATA_FILE" ]]; then
    data_args+=(--data "@${REQUEST_DATA_FILE}")
  fi

  if (( ${#data_args[@]} > 0 )); then
    curl_header_args+=(-H 'Content-Type: application/json')
  fi

  for header in "${EXTRA_HEADERS[@]}"; do
    curl_header_args+=(-H "$header")
  done

  while (( attempt <= max_attempts )); do
    : >"$header_file"
    : >"$body_file"
    : >"$stderr_file"

    set +e
    http_code="$(
      curl \
        --silent \
        --show-error \
        --output "$body_file" \
        --dump-header "$header_file" \
        --write-out '%{http_code}' \
        --connect-timeout "$connect_timeout" \
        --max-time "$max_time" \
        --request "$METHOD" \
        -H "Authorization: Bearer ${GH_TOKEN:-${GITHUB_TOKEN:-}}" \
        -H 'Accept: application/vnd.github+json' \
        -H 'X-GitHub-Api-Version: 2022-11-28' \
        "${data_args[@]}" \
        "${curl_header_args[@]}" \
        "$url" \
        2>"$stderr_file"
    )"
    curl_rc=$?
    set -e

    if [[ "$curl_rc" -eq 0 && "$http_code" =~ ^2 ]]; then
      if [[ "$PRINT_HEADERS" -eq 1 ]]; then
        cat "$header_file" >&2
      fi
      cat "$body_file"
      rm -f "$header_file" "$body_file" "$stderr_file"
      return 0
    fi

    if retryable_curl_rc "$curl_rc" || retryable_http_code "$http_code"; then
      if (( attempt == max_attempts )); then
        if [[ "$curl_rc" -ne 0 ]]; then
          summary="$(tr '\n' ' ' <"$stderr_file" | sed 's/[[:space:]]\+/ /g; s/^ //; s/ $//')"
        else
          summary="$(body_summary "$body_file")"
        fi
        echo "[错误] GitHub API 重试耗尽: $summary" >&2
        rm -f "$header_file" "$body_file" "$stderr_file"
        exit 75
      fi

      retry_after="$(extract_retry_after "$header_file")"
      if [[ -n "$retry_after" && "$retry_after" =~ ^[0-9]+$ ]]; then
        delay="$retry_after"
      fi

      if [[ "$curl_rc" -ne 0 ]]; then
        summary="$(tr '\n' ' ' <"$stderr_file" | sed 's/[[:space:]]\+/ /g; s/^ //; s/ $//')"
      else
        summary="$(body_summary "$body_file")"
      fi

      echo "[警告] GitHub API 调用失败，第 ${attempt}/${max_attempts} 次，${delay} 秒后重试: ${summary}" >&2
      sleep "$delay"
      attempt=$((attempt + 1))
      delay=$((delay * 2))
      if (( delay > max_delay )); then
        delay="$max_delay"
      fi
      continue
    fi

    if [[ "$PRINT_HEADERS" -eq 1 ]]; then
      cat "$header_file" >&2
    fi

    if [[ -s "$body_file" ]]; then
      cat "$body_file" >&2
    elif [[ -s "$stderr_file" ]]; then
      cat "$stderr_file" >&2
    else
      echo "[错误] GitHub API 调用失败，HTTP ${http_code:-unknown}" >&2
    fi

    rm -f "$header_file" "$body_file" "$stderr_file"
    if [[ "$curl_rc" -eq 0 ]]; then
      exit 1
    fi
    exit "$curl_rc"
  done
}

parse_args "$@"
perform_request