import { createError } from 'h3'
import { getPostgresClient } from './postgres-client'

/**
 * @typedef {Object} MemberUser
 * @property {string} id - 사용자 ID
 * @property {string} username - 사용자명
 * @property {string} email - 이메일
 * @property {string} passwordHash - 비밀번호 해시
 * @property {string} avatarUrl - 아바타 URL
 * @property {string} createdAt - 생성 시각(ISO)
 * @property {string} updatedAt - 수정 시각(ISO)
 * @property {string | null} lastSeenAt - 최근 접속 시각(ISO)
 * @property {string} lastSeenIp - 최근 접속 IP
 */

/**
 * DB 클라이언트 조회 (필수)
 * @returns {ReturnType<typeof import('postgres').default>} postgres sql 클라이언트
 */
const requireSql = () => {
  const sql = getPostgresClient()
  if (!sql) {
    throw createError({
      statusCode: 500,
      message: '데이터베이스 설정이 필요합니다.'
    })
  }
  return sql
}

/**
 * 이메일로 회원 조회
 * @param {string} email - 이메일
 * @returns {Promise<MemberUser | null>} 회원
 */
export const getUserByEmail = async (email) => {
  const sql = requireSql()
  const rows = await sql`
    SELECT
      id,
      username,
      email,
      password_hash AS "passwordHash",
      avatar_url AS "avatarUrl",
      created_at AS "createdAt",
      updated_at AS "updatedAt",
      last_seen_at AS "lastSeenAt",
      last_seen_ip AS "lastSeenIp"
    FROM users
    WHERE email = ${email}
    LIMIT 1
  `

  return rows?.[0] || null
}

/**
 * ID로 회원 조회
 * @param {string} id - 사용자 ID
 * @returns {Promise<Omit<MemberUser, 'passwordHash'> | null>} 회원
 */
export const getUserById = async (id) => {
  const sql = requireSql()
  const rows = await sql`
    SELECT
      id,
      username,
      email,
      avatar_url AS "avatarUrl",
      created_at AS "createdAt",
      updated_at AS "updatedAt",
      last_seen_at AS "lastSeenAt",
      last_seen_ip AS "lastSeenIp"
    FROM users
    WHERE id = ${id}
    LIMIT 1
  `

  return rows?.[0] || null
}

/**
 * ID로 회원 조회(비밀번호 포함)
 * @param {string} id - 사용자 ID
 * @returns {Promise<MemberUser | null>} 회원
 */
export const getUserByIdWithPassword = async (id) => {
  const sql = requireSql()
  const rows = await sql`
    SELECT
      id,
      username,
      email,
      password_hash AS "passwordHash",
      avatar_url AS "avatarUrl",
      created_at AS "createdAt",
      updated_at AS "updatedAt",
      last_seen_at AS "lastSeenAt",
      last_seen_ip AS "lastSeenIp"
    FROM users
    WHERE id = ${id}
    LIMIT 1
  `

  return rows?.[0] || null
}

/**
 * 회원 생성
 * @param {{ username: string, email: string, passwordHash: string }} input - 입력
 * @returns {Promise<Omit<MemberUser, 'passwordHash'>>} 생성된 회원
 */
export const createUser = async (input) => {
  const sql = requireSql()

  const rows = await sql`
    INSERT INTO users (username, email, password_hash, avatar_url)
    VALUES (${input.username}, ${input.email}, ${input.passwordHash}, '')
    RETURNING
      id,
      username,
      email,
      avatar_url AS "avatarUrl",
      created_at AS "createdAt",
      updated_at AS "updatedAt",
      last_seen_at AS "lastSeenAt",
      last_seen_ip AS "lastSeenIp"
  `

  const created = rows?.[0]
  if (!created) {
    throw createError({
      statusCode: 500,
      message: '회원 생성에 실패했습니다.'
    })
  }

  return created
}

/**
 * 회원 최근 활동 정보를 기록한다.
 * @param {{ userId: string, ip: string }} input - 사용자 ID와 접속 IP
 * @returns {Promise<void>}
 */
export const touchUserActivity = async (input) => {
  const sql = requireSql()
  await sql`
    UPDATE users
    SET
      last_seen_at = now(),
      last_seen_ip = ${input.ip},
      updated_at = now()
    WHERE id = ${input.userId}
  `
}

/**
 * 회원 프로필 수정
 * @param {{ userId: string, username: string, avatarUrl: string }} input - 수정 값
 * @returns {Promise<Omit<MemberUser, 'passwordHash'> | null>} 수정된 회원
 */
export const updateMemberProfile = async (input) => {
  const sql = requireSql()
  const rows = await sql`
    UPDATE users
    SET
      username = ${input.username},
      avatar_url = ${input.avatarUrl},
      updated_at = now()
    WHERE id = ${input.userId}
    RETURNING
      id,
      username,
      email,
      avatar_url AS "avatarUrl",
      created_at AS "createdAt",
      updated_at AS "updatedAt",
      last_seen_at AS "lastSeenAt",
      last_seen_ip AS "lastSeenIp"
  `

  return rows?.[0] || null
}

/**
 * 회원 비밀번호 변경
 * @param {{ userId: string, passwordHash: string }} input - 수정 값
 * @returns {Promise<void>}
 */
export const updateMemberPassword = async (input) => {
  const sql = requireSql()
  await sql`
    UPDATE users
    SET
      password_hash = ${input.passwordHash},
      updated_at = now()
    WHERE id = ${input.userId}
  `
}

/**
 * 회원 탈퇴
 * @param {string} userId - 사용자 ID
 * @returns {Promise<void>}
 */
export const deleteMember = async (userId) => {
  const sql = requireSql()
  await sql`
    DELETE FROM users
    WHERE id = ${userId}
  `
}

/**
 * 사용자명 중복 확인
 * @param {{ username: string, excludeUserId?: string }} input - 사용자명과 제외 사용자 ID
 * @returns {Promise<boolean>} 중복 여부
 */
export const isUsernameTaken = async (input) => {
  const sql = requireSql()
  const rows = input.excludeUserId
    ? await sql`
      SELECT id
      FROM users
      WHERE lower(username) = lower(${input.username})
        AND id <> ${input.excludeUserId}
      LIMIT 1
    `
    : await sql`
      SELECT id
      FROM users
      WHERE lower(username) = lower(${input.username})
      LIMIT 1
    `

  return Boolean(rows?.[0])
}

/**
 * 관리자용 회원 목록 조회(댓글 활동 포함)
 * @returns {Promise<Array<{ id: string, username: string, email: string, avatarUrl: string, createdAt: string, updatedAt: string, lastSeenAt: string | null, lastSeenIp: string, commentCount: number, activityStatus: string }>>} 회원 목록
 */
export const listMembersForAdmin = async () => {
  const sql = requireSql()
  const rows = await sql`
    SELECT
      users.id,
      users.username,
      users.email,
      users.avatar_url AS "avatarUrl",
      users.created_at AS "createdAt",
      users.updated_at AS "updatedAt",
      users.last_seen_at AS "lastSeenAt",
      users.last_seen_ip AS "lastSeenIp",
      COALESCE(count(comments.id), 0)::int AS "commentCount"
    FROM users
    LEFT JOIN comments ON comments.user_id = users.id AND comments.status = 'published'
    GROUP BY users.id
    ORDER BY users.created_at DESC
  `

  return rows.map((row) => {
    const lastSeenAt = row.lastSeenAt ? row.lastSeenAt.toISOString() : null
    const isActive = row.lastSeenAt
      ? Date.now() - new Date(row.lastSeenAt).getTime() <= 1000 * 60 * 60 * 24 * 30
      : false

    return {
      id: row.id,
      username: row.username,
      email: row.email,
      avatarUrl: row.avatarUrl || '',
      createdAt: row.createdAt.toISOString(),
      updatedAt: row.updatedAt.toISOString(),
      lastSeenAt,
      lastSeenIp: row.lastSeenIp || '',
      commentCount: Number(row.commentCount || 0),
      activityStatus: isActive ? '활성' : '비활성'
    }
  })
}