package user

import (
	"context"
	"database/sql"
	"errors"
	"fmt"
	"strings"
	"time"

	"github.com/zeromicro/go-zero/core/stores/cache"
	"github.com/zeromicro/go-zero/core/stores/sqlx"
)

var ErrUpdateConflict = errors.New("update conflict: data has been modified by another operation")

// ErrTokenVersionMismatch 表示令牌版本与数据库当前版本不一致，刷新令牌失败。
// 典型场景：refreshToken rotation 并发到达 —— 只有持有当前 tokenVersion 的那一次能原子递增成功，
// 其余全部返回该错误，防止两个请求都"换到"新令牌（导致会话劫持）。
var ErrTokenVersionMismatch = errors.New("token version mismatch")

var _ SysUserModel = (*customSysUserModel)(nil)

type (
	SysUserModel interface {
		sysUserModel
		FindListByPage(ctx context.Context, page, pageSize int64) ([]*SysUser, int64, error)
		FindListByProductMembers(ctx context.Context, productCode string, page, pageSize int64) ([]*SysUser, map[int64]string, int64, error)
		FindByIds(ctx context.Context, ids []int64) ([]*SysUser, error)
		FindIdsByDeptId(ctx context.Context, deptId int64) ([]int64, error)
		UpdateProfile(ctx context.Context, id int64, username string, nickname, email, phone, remark string, deptId, newStatus int64, statusChanged bool, expectedUpdateTime int64) error
		UpdatePassword(ctx context.Context, id int64, password string, mustChangePassword int64) error
		UpdateStatus(ctx context.Context, id int64, status int64) error
		IncrementTokenVersion(ctx context.Context, id int64) (int64, error)
		IncrementTokenVersionIfMatch(ctx context.Context, id int64, username string, expected int64) (int64, error)
	}

	customSysUserModel struct {
		*defaultSysUserModel
	}
)

func NewSysUserModel(conn sqlx.SqlConn, c cache.CacheConf, cachePrefix string, opts ...cache.Option) SysUserModel {
	return &customSysUserModel{
		defaultSysUserModel: newSysUserModel(conn, c, cachePrefix, opts...),
	}
}

func (m *customSysUserModel) FindListByPage(ctx context.Context, page, pageSize int64) ([]*SysUser, int64, error) {
	var total int64
	countQuery := fmt.Sprintf("SELECT COUNT(*) FROM %s", m.table)
	if err := m.QueryRowNoCacheCtx(ctx, &total, countQuery); err != nil {
		return nil, 0, err
	}

	var list []*SysUser
	query := fmt.Sprintf("SELECT %s FROM %s ORDER BY id DESC LIMIT ?,?", sysUserRows, m.table)
	if err := m.QueryRowsNoCacheCtx(ctx, &list, query, (page-1)*pageSize, pageSize); err != nil {
		return nil, 0, err
	}

	return list, total, nil
}

type UserWithMemberType struct {
	SysUser
	MemberType string `db:"memberType"`
}

func (m *customSysUserModel) FindListByProductMembers(ctx context.Context, productCode string, page, pageSize int64) ([]*SysUser, map[int64]string, int64, error) {
	memberTable := "`sys_product_member`"

	var total int64
	countQuery := fmt.Sprintf("SELECT COUNT(*) FROM %s u INNER JOIN %s pm ON u.`id` = pm.`userId` WHERE pm.`productCode` = ?", m.table, memberTable)
	if err := m.QueryRowNoCacheCtx(ctx, &total, countQuery, productCode); err != nil {
		return nil, nil, 0, err
	}

	var list []*UserWithMemberType
	fields := strings.Join(sysUserFieldNames, ",u.")
	query := fmt.Sprintf("SELECT u.%s, pm.`memberType` FROM %s u INNER JOIN %s pm ON u.`id` = pm.`userId` WHERE pm.`productCode` = ? ORDER BY u.`id` DESC LIMIT ?,?", fields, m.table, memberTable)
	if err := m.QueryRowsNoCacheCtx(ctx, &list, query, productCode, (page-1)*pageSize, pageSize); err != nil {
		return nil, nil, 0, err
	}

	users := make([]*SysUser, len(list))
	memberMap := make(map[int64]string, len(list))
	for i, item := range list {
		users[i] = &item.SysUser
		memberMap[item.Id] = item.MemberType
	}

	return users, memberMap, total, nil
}

func (m *customSysUserModel) FindIdsByDeptId(ctx context.Context, deptId int64) ([]int64, error) {
	var ids []int64
	query := fmt.Sprintf("SELECT `id` FROM %s WHERE `deptId` = ?", m.table)
	if err := m.QueryRowsNoCacheCtx(ctx, &ids, query, deptId); err != nil {
		return nil, err
	}
	return ids, nil
}

func (m *customSysUserModel) UpdateProfile(ctx context.Context, id int64, username string, nickname, email, phone, remark string, deptId, newStatus int64, statusChanged bool, expectedUpdateTime int64) error {
	sysUserIdKey := fmt.Sprintf("%s%v", cacheSysUserIdPrefix, id)
	sysUserUsernameKey := fmt.Sprintf("%s%v", cacheSysUserUsernamePrefix, username)
	now := time.Now().Unix()

	res, err := m.ExecCtx(ctx, func(ctx context.Context, conn sqlx.SqlConn) (sql.Result, error) {
		if statusChanged {
			query := fmt.Sprintf("UPDATE %s SET `nickname`=?, `email`=?, `phone`=?, `remark`=?, `deptId`=?, `status`=?, `tokenVersion`=`tokenVersion`+1, `updateTime`=? WHERE `id`=? AND `updateTime`=?", m.table)
			return conn.ExecCtx(ctx, query, nickname, email, phone, remark, deptId, newStatus, now, id, expectedUpdateTime)
		}
		query := fmt.Sprintf("UPDATE %s SET `nickname`=?, `email`=?, `phone`=?, `remark`=?, `deptId`=?, `updateTime`=? WHERE `id`=? AND `updateTime`=?", m.table)
		return conn.ExecCtx(ctx, query, nickname, email, phone, remark, deptId, now, id, expectedUpdateTime)
	}, sysUserIdKey, sysUserUsernameKey)
	if err != nil {
		return err
	}
	affected, _ := res.RowsAffected()
	if affected == 0 {
		return ErrUpdateConflict
	}
	return nil
}

func (m *customSysUserModel) UpdatePassword(ctx context.Context, id int64, password string, mustChangePassword int64) error {
	data, err := m.FindOne(ctx, id)
	if err != nil {
		return err
	}

	sysUserIdKey := fmt.Sprintf("%s%v", cacheSysUserIdPrefix, id)
	sysUserUsernameKey := fmt.Sprintf("%s%v", cacheSysUserUsernamePrefix, data.Username)
	// 乐观锁：WHERE 叠加 updateTime 与 FindOne 拿到的一致。避免 FindOne → Exec 之间并发改密把
	// 本次写盖成"最后一写赢"、或目标行被删除后仍返回成功造成语义欺骗（见审计 M-2）。
	expectedUpdateTime := data.UpdateTime
	res, err := m.ExecCtx(ctx, func(ctx context.Context, conn sqlx.SqlConn) (sql.Result, error) {
		query := fmt.Sprintf("UPDATE %s SET `password` = ?, `mustChangePassword` = ?, `tokenVersion` = `tokenVersion` + 1, `updateTime` = ? WHERE `id` = ? AND `updateTime` = ?", m.table)
		return conn.ExecCtx(ctx, query, password, mustChangePassword, time.Now().Unix(), id, expectedUpdateTime)
	}, sysUserIdKey, sysUserUsernameKey)
	if err != nil {
		return err
	}
	if affected, _ := res.RowsAffected(); affected == 0 {
		// 行被删除或被并发改过：对外统一回 ErrUpdateConflict，避免对已删除用户返回 nil 让上层
		// 误判为"改密成功"（审计 M-2）。
		return ErrUpdateConflict
	}
	return nil
}

func (m *customSysUserModel) UpdateStatus(ctx context.Context, id int64, status int64) error {
	data, err := m.FindOne(ctx, id)
	if err != nil {
		return err
	}

	sysUserIdKey := fmt.Sprintf("%s%v", cacheSysUserIdPrefix, id)
	sysUserUsernameKey := fmt.Sprintf("%s%v", cacheSysUserUsernamePrefix, data.Username)
	res, err := m.ExecCtx(ctx, func(ctx context.Context, conn sqlx.SqlConn) (sql.Result, error) {
		query := fmt.Sprintf("UPDATE %s SET `status` = ?, `tokenVersion` = `tokenVersion` + 1, `updateTime` = ? WHERE `id` = ?", m.table)
		return conn.ExecCtx(ctx, query, status, time.Now().Unix(), id)
	}, sysUserIdKey, sysUserUsernameKey)
	if err != nil {
		return err
	}
	if affected, _ := res.RowsAffected(); affected == 0 {
		// 目标用户在 FindOne 后被并发删除；返回 ErrUpdateConflict 让上层区分"冻结生效"与"目标已消失"
		// （审计 M-2）。
		return ErrUpdateConflict
	}
	return nil
}

// IncrementTokenVersion 强制递增当前用户的 tokenVersion，让**所有**已签发的 access/refresh 立即失效。
//
// WARN: 仅限"强制全量会话失效"场景调用——主动 Logout 或封禁/重置密码。Refresh / Rotate 场景
// 必须调用 IncrementTokenVersionIfMatch 走 CAS 语义，否则会回到 R5 以前的并发 rotate 窗口，
// 两次并发 refresh 都能换到新令牌，等同于会话劫持（见审计 L-2）。
// 调用前请先走 TokenOpLimiter 等限流，避免被反复触发把合法用户 kick 出登录。
func (m *customSysUserModel) IncrementTokenVersion(ctx context.Context, id int64) (int64, error) {
	data, err := m.FindOne(ctx, id)
	if err != nil {
		return 0, err
	}

	sysUserIdKey := fmt.Sprintf("%s%v", cacheSysUserIdPrefix, id)
	sysUserUsernameKey := fmt.Sprintf("%s%v", cacheSysUserUsernamePrefix, data.Username)

	var newVersion int64
	err = m.TransactCtx(ctx, func(ctx context.Context, session sqlx.Session) error {
		query := fmt.Sprintf("UPDATE %s SET `tokenVersion` = LAST_INSERT_ID(`tokenVersion` + 1), `updateTime` = ? WHERE `id` = ?", m.table)
		if _, err := session.ExecCtx(ctx, query, time.Now().Unix(), id); err != nil {
			return err
		}
		return session.QueryRowCtx(ctx, &newVersion, "SELECT LAST_INSERT_ID()")
	})
	if err != nil {
		return 0, err
	}

	_ = m.DelCacheCtx(ctx, sysUserIdKey, sysUserUsernameKey)
	return newVersion, nil
}

// IncrementTokenVersionIfMatch 原子递增 tokenVersion；仅当 DB 里当前 tokenVersion == expected 时才会生效。
// 这是 refreshToken rotation 的原子 CAS：两个并发的刷新请求只有一个能命中 WHERE tokenVersion=expected，
// 另一个 affected=0 返回 ErrTokenVersionMismatch，从而避免"两边都换到新令牌"的会话劫持窗口。
//
// 由上游透传 username 以便构造 cacheSysUserUsernamePrefix 的缓存键进行失效，避免为此多查一次 FindOne
// （见审计 M-8）。上游通常已经通过 UserDetailsLoader.Load 拿到 username，零额外成本。
func (m *customSysUserModel) IncrementTokenVersionIfMatch(ctx context.Context, id int64, username string, expected int64) (int64, error) {
	sysUserIdKey := fmt.Sprintf("%s%v", cacheSysUserIdPrefix, id)
	sysUserUsernameKey := fmt.Sprintf("%s%v", cacheSysUserUsernamePrefix, username)

	var newVersion int64
	err := m.TransactCtx(ctx, func(ctx context.Context, session sqlx.Session) error {
		query := fmt.Sprintf("UPDATE %s SET `tokenVersion` = LAST_INSERT_ID(`tokenVersion` + 1), `updateTime` = ? WHERE `id` = ? AND `tokenVersion` = ?", m.table)
		res, err := session.ExecCtx(ctx, query, time.Now().Unix(), id, expected)
		if err != nil {
			return err
		}
		affected, _ := res.RowsAffected()
		if affected == 0 {
			return ErrTokenVersionMismatch
		}
		return session.QueryRowCtx(ctx, &newVersion, "SELECT LAST_INSERT_ID()")
	})
	if err != nil {
		return 0, err
	}

	_ = m.DelCacheCtx(ctx, sysUserIdKey, sysUserUsernameKey)
	return newVersion, nil
}

func (m *customSysUserModel) FindByIds(ctx context.Context, ids []int64) ([]*SysUser, error) {
	if len(ids) == 0 {
		return nil, nil
	}
	placeholders := make([]string, len(ids))
	args := make([]interface{}, len(ids))
	for i, id := range ids {
		placeholders[i] = "?"
		args[i] = id
	}
	var list []*SysUser
	query := fmt.Sprintf("SELECT %s FROM %s WHERE `id` IN (%s)", sysUserRows, m.table, strings.Join(placeholders, ","))
	if err := m.QueryRowsNoCacheCtx(ctx, &list, query, args...); err != nil {
		return nil, err
	}
	return list, nil
}