#!/usr/bin/env bash
# ============================================================
# HF User helper - 提供 HF 账户切换和 token 获取的共享函数
#
# 提供以下公共 API（参照 bootstrap-hf.sh 的实现）:
#   - get_hf_username           获取当前 HF 用户名
#   - read_current_hf_token     从 env / cache 文件读取 token
#   - login_with_hf_token       用 token 登录 HF
#   - prompt_hf_account_switch  检测/询问/切换 HF 账户
#   - require_hf_token          必要时 prompt 后获取 token
#   - prompt_yes_no             y/n 询问（非 TTY 不阻塞）
#   - prompt_line / prompt_required
#   - prompt_secret_optional / prompt_secret_required
#   - trim / info / warn / error / die
#
# 用法:
#   source "$SCRIPT_DIR/_hf_user.sh"
#   HF_TOKEN="$(require_hf_token)" || exit 1
#   export HF_TOKEN
#
# 设计:
#   - 所有 prompt 函数在 stdin 不是 TTY 时使用默认值 / 返回错误，
#     避免 c63f250 修复的"stdin 非 TTY 进入死循环"问题
#   - login 成功后调用 hf auth whoami 验证，切换时输出 switched 信息
#   - 不实现 RESTORE_HF_LOGIN_* 恢复机制（单命令工具不需要）
# ============================================================

# ---- Fix terminal for interactive input ----
if [[ -t 0 ]]; then
    stty sane 2>/dev/null || true
fi

# ---- Ensure hf is in PATH (handles SSH_ASKPASS restricted env) ----
_HF_EXTRA_PATH="/root/.local/bin"
if [[ ":$PATH:" != *":$_HF_EXTRA_PATH:"* ]]; then
    export PATH="$_HF_EXTRA_PATH:$PATH"
fi

# ---- 通用辅助函数 ----
trim() {
  printf '%s' "$1" | sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//'
}

info() {
  printf '%s\n' "$*"
}

warn() {
  printf 'warning: %s\n' "$*" >&2
}

error() {
  printf 'error: %s\n' "$*" >&2
}

die() {
  error "$1"
  exit 1
}

# ---- 输入提示 ----
prompt_line() {
  local prompt="$1"
  local default_value="${2:-}"
  local value=""

  if [[ -t 0 ]]; then
    if [[ -n "$default_value" ]]; then
      read -r -p "$prompt [$default_value]: " value || true
    else
      read -r -p "$prompt: " value || true
    fi
    value="$(printf '%s' "$value" | tr -d '\r\n')"
    if [[ -z "$value" ]]; then
      value="$default_value"
    fi
  else
    value="$default_value"
  fi
  printf '%s' "$value"
}

prompt_required() {
  local prompt="$1"
  local default_value="${2:-}"
  local value=""

  while [[ -z "$value" ]]; do
    value="$(prompt_line "$prompt" "$default_value")"
    if [[ -z "$value" ]]; then
      if [[ -t 0 ]]; then
        printf 'This value is required.\n' >&2
      else
        # 非 TTY 模式无法补全，直接返回空（调用方应 die）
        printf '%s' ""
        return 1
      fi
    fi
  done
  printf '%s' "$value"
}

prompt_secret_optional() {
  local prompt="$1"
  local value=""
  local char=""

  if [[ -t 0 && -t 1 ]]; then
    printf '%s: ' "$prompt" >&2
    while IFS= read -r -s -n 1 char; do
      if [[ -z "$char" ]]; then
        break
      fi
      case "$char" in
        $'\177'|$'\b')
          if [[ -n "$value" ]]; then
            value="${value%?}"
            printf '\b \b' >&2
          fi
          ;;
        *)
          value+="$char"
          printf '*' >&2
          ;;
      esac
    done
    printf '\n' >&2
  else
    # 非 TTY：直接读一行（无回显），不阻塞
    read -r -p "$prompt: " value || true
  fi
  printf '%s' "$(trim "${value:-}")"
}

prompt_secret_required() {
  local prompt="$1"
  local value=""

  while [[ -z "$value" ]]; do
    value="$(prompt_secret_optional "$prompt")"
    value="$(trim "$value")"
    if [[ -z "$value" ]]; then
      if [[ -t 0 ]]; then
        printf 'This value is required.\n' >&2
      else
        # 非 TTY: 不阻塞，返回空
        printf '%s' ""
        return 1
      fi
    fi
  done
  printf '%s' "$value"
}

# y/n 询问
#   $1: prompt 文本
#   $2: 默认值 "y" 或 "n"（默认 n）
# 输出: "yes" 或 "no"
# 非 TTY 时直接使用默认值，不阻塞
prompt_yes_no() {
  local prompt="$1"
  local default_value="${2:-n}"
  local answer=""
  local hint="[y/N]"

  if [[ "$default_value" == "y" ]]; then
    hint="[Y/n]"
  fi

  if [[ -t 0 ]]; then
    while true; do
      read -r -p "$prompt $hint: " answer || true
      answer="$(printf '%s' "$answer" | tr -d '\r\n' | tr '[:upper:]' '[:lower:]')"
      if [[ -z "$answer" ]]; then
        answer="$default_value"
      fi
      case "$answer" in
        y|yes)
          printf 'yes'
          return 0
          ;;
        n|no)
          printf 'no'
          return 0
          ;;
        *)
          printf 'Please answer y or n.\n' >&2
          ;;
      esac
    done
  else
    # 非 TTY：使用默认值，不阻塞
    if [[ "$default_value" == "y" ]]; then
      printf 'yes'
    else
      printf 'no'
    fi
  fi
}

# ---- Token 处理 ----

# 解析 whoami 输出，提取 username
# 接受两种格式: "user: <name>" 或 "Logged in as <name>"
_parse_whoami_username() {
  local output="$1"
  local username

  username="$(printf '%s\n' "$output" | sed -nE 's/^[[:space:]]*user:[[:space:]]*([^[:space:]]+).*/\1/p' | head -n 1)"
  if [[ -z "$username" ]]; then
    username="$(printf '%s\n' "$output" | sed -nE 's/.*[Ll]ogged in as[[:space:]]+([^[:space:]]+).*/\1/p' | head -n 1)"
  fi
  printf '%s' "$username"
}

# 读取当前可用的 token
# 优先级: HUGGINGFACE_HUB_TOKEN > HF_TOKEN > HF_TOKEN_FILE > ~/.cache/huggingface/token
read_current_hf_token() {
  if [[ -n "${HUGGINGFACE_HUB_TOKEN:-}" ]]; then
    printf '%s' "${HUGGINGFACE_HUB_TOKEN}" | tr -d '\r\n'
    return 0
  fi
  if [[ -n "${HF_TOKEN:-}" ]]; then
    printf '%s' "${HF_TOKEN}" | tr -d '\r\n'
    return 0
  fi
  local token_file="${HF_TOKEN_FILE:-$HOME/.cache/huggingface/token}"
  if [[ -f "$token_file" ]]; then
    head -n 1 "$token_file" | tr -d '\r\n'
    return 0
  fi
  printf ''
}

# 用 token 登录 HF
login_with_hf_token() {
  local token="$1"
  hf auth login --token "$token" >/dev/null 2>&1 || die "hf auth login with token failed."
}

# ---- 核心 API ----

# 获取当前 HF 用户名
# 返回: HF username 或 空字符串
# 实现与之前 _hf_user.sh:17-61 一致
get_hf_username() {
  local whoami_output
  local username

  # 方法1: 通过 hf auth whoami
  whoami_output="$(hf auth whoami 2>&1 || true)"
  username="$(_parse_whoami_username "$whoami_output")"
  if [[ -n "$username" ]]; then
    printf '%s' "$username"
    return 0
  fi

  # 方法2: 通过 Python huggingface_hub（fallback）
  local hf_token_file="${HF_TOKEN_FILE:-$HOME/.cache/huggingface/token}"
  local token_from_cache=""
  if [[ -f "$hf_token_file" ]]; then
    token_from_cache="$(head -n 1 "$hf_token_file" | tr -d '\r\n')"
  fi
  if [[ -n "$token_from_cache" ]]; then
    username="$(
      HF_API_TOKEN="$token_from_cache" python3 - <<'PY' 2>/dev/null || true
from huggingface_hub import HfApi
import os
token = (os.environ.get("HF_API_TOKEN") or "").strip() or None
api = HfApi(token=token)
data = api.whoami(token=token)
name = data.get("name", "") if isinstance(data, dict) else ""
print((name or "").strip())
PY
    )"
    username="$(printf '%s' "$username" | tr -d '\r\n')"
    if [[ -n "$username" ]]; then
      printf '%s' "$username"
      return 0
    fi
  fi

  return 1
}

# HF 账户切换提示
# 已登录时:
#   - TTY: 询问 "Use this user? <name> [Y/n]"，如拒绝则 prompt 新 token 并切换
#   - 非 TTY: 静默使用当前用户
# 未登录时:
#   - return 1
prompt_hf_account_switch() {
  local whoami_output
  local current_username

  whoami_output="$(hf auth whoami 2>&1 || true)"
  current_username="$(_parse_whoami_username "$whoami_output")"
  if [[ -z "$current_username" ]]; then
    return 1
  fi

  if [[ -t 0 ]]; then
    local use_current
    use_current="$(prompt_yes_no "HF CLI is logged in as '$current_username'. Use this user?" "y")"
    if [[ "$use_current" == "yes" ]]; then
      return 0
    fi

    # 切换账户
    while true; do
      local new_token
      new_token="$(prompt_secret_required "HF_TOKEN to switch to a different account")" || {
        warn "Empty token, please try again or press Ctrl+C to cancel"
        continue
      }
      if [[ -z "$new_token" ]]; then
        warn "Empty token, please try again or press Ctrl+C to cancel"
        continue
      fi
      if ! hf auth login --token "$new_token" >/dev/null 2>&1; then
        warn "HF login failed, please try again"
        continue
      fi
      local verify_output
      verify_output="$(hf auth whoami 2>&1 || true)"
      local new_username
      new_username="$(_parse_whoami_username "$verify_output")"
      if [[ -n "$new_username" && "$new_username" != "$current_username" ]]; then
        info "HF account switched: $current_username -> $new_username"
      elif [[ -n "$new_username" ]]; then
        info "HF login successful as: $new_username"
      else
        info "HF login successful"
      fi
      return 0
    done
  fi

  return 0
}

# 获取 HF token，必要时提示用户登录
# 优先级:
#   1. prompt_hf_account_switch（已登录则用当前；TTY 下可切换）
#   2. env (HUGGINGFACE_HUB_TOKEN / HF_TOKEN)
#   3. ~/.cache/huggingface/token
#   4. TTY 下交互式 prompt
#   5. die
# 成功时通过 stdout 输出 token
require_hf_token() {
  local token=""

  # 1. 尝试切换（如果已登录）
  if prompt_hf_account_switch; then
    token="$(read_current_hf_token)"
    [[ -n "$token" ]] && { printf '%s' "$token"; return 0; }
  fi

  # 2. 回退到环境变量 / cache 文件
  token="$(read_current_hf_token)"
  [[ -n "$token" ]] && { printf '%s' "$token"; return 0; }

  # 3. 最后手段: 交互式 prompt
  if [[ -t 0 ]]; then
    info "HF CLI is not logged in and HF_TOKEN is not set."
    while true; do
      local new_token
      new_token="$(prompt_secret_required "HF_TOKEN (required for HF login)")" || {
        # 非 TTY 或 Ctrl+C
        break
      }
      if [[ -z "$new_token" ]]; then
        warn "Empty token, please try again or press Ctrl+C to cancel"
        continue
      fi
      if ! hf auth login --token "$new_token" >/dev/null 2>&1; then
        warn "HF login failed, please try again"
        continue
      fi
      local verify_output
      verify_output="$(hf auth whoami 2>&1 || true)"
      local new_username
      new_username="$(_parse_whoami_username "$verify_output")"
      if [[ -n "$new_username" ]]; then
        info "HF login successful as: $new_username"
      else
        info "HF login successful"
      fi
      printf '%s' "$new_token"
      return 0
    done
  fi

  die "HF_TOKEN is required. Set HF_TOKEN env var or run: hf auth login"
}