package wechatmp

import (
	"errors"
	"strings"
	"time"

	"server/models"
)

// =============================================================
// 注册「账号注册」验证码：网页发起 → 展示带参二维码（scene）→
// 用户微信扫码关注 → 服务号被动回复 6 位验证码 → 网页填码核销。
// 复用 yz_platform_wechat_mp_verify_code 会话表（bind_type="register"），
// 扫码事件回复走通用 handleScanScene，无需新增事件处理。
// =============================================================

// WechatBindTypeRegister 注册验证码会话类型（yz_platform_wechat_mp_verify_code.bind_type）
const WechatBindTypeRegister = "register"

// StartRegisterVerify 创建注册验证码会话并生成带参二维码。
// 带参二维码生成失败（未认证公众号 48001 等）时回退：qrURL 为空、
// notice 返回引导（用户在公众号内发送「注册」获取验证码），scene 仍有效可轮询。
func StartRegisterVerify(ttl time.Duration) (scene, qrURL, notice string, expireAt time.Time, err error) {
	if ttl <= 0 {
		ttl = DefaultVerifyTTL
	}
	cfg, err := LoadEnabledConfig()
	if err != nil {
		return "", "", "", time.Time{}, err
	}
	scene = randomScene()
	code := randomCode6()
	now := time.Now()
	expireAt = now.Add(ttl)

	row := &models.WechatMpVerifyCode{
		Scene:      scene,
		Code:       code,
		Status:     models.WechatVerifyStatusWaiting,
		BindType:   WechatBindTypeRegister,
		ExpireAt:   &expireAt,
		CreateTime: now,
		UpdateTime: &now,
	}
	if _, err = models.Orm.Insert(row); err != nil {
		return "", "", "", time.Time{}, err
	}
	qrURL, err = CreateQRCode(cfg, scene, int(ttl.Seconds())+120)
	if err != nil {
		// 不吞真实错误：与扫码登录 StartScanLogin 一致，把微信返回的
		// errcode 与排查建议（IP 白名单 / 48001 未认证等）透出，便于定位；
		// 同时保留「公众号内发送注册」兜底路径，会话仍有效可轮询核销。
		notice := "请在公众号内直接发送「注册」获取验证码"
		var apiErr *APIError
		if errors.As(err, &apiErr) {
			notice = "生成带参二维码失败（" + apiErr.Error() + "）。" + notice
			if hint := apiErr.Explain(); hint != "" {
				notice += "：" + hint
			}
		} else {
			notice = "生成带参二维码失败：" + err.Error() + "。" + notice
		}
		return scene, "", notice, expireAt, nil
	}
	return scene, qrURL, "", expireAt, nil
}

// GetRegisterVerifyStatus 查询注册会话扫码状态（网页轮询展示「已扫码」）
func GetRegisterVerifyStatus(scene string) (scanned bool, expireAt time.Time, err error) {
	row, err := GetVerifyCode(scene)
	if err != nil {
		return false, time.Time{}, err
	}
	if row.ExpireAt != nil {
		expireAt = *row.ExpireAt
	}
	if row.BindType != WechatBindTypeRegister {
		return false, expireAt, ErrSceneInvalid
	}
	return row.Status == models.WechatVerifyStatusScanned, expireAt, nil
}

// ConfirmRegisterVerify 核销注册验证码：校验会话归属与状态，返回扫码人 openid。
// 要求会话已被扫码（openid 已写入）、验证码匹配，核销后一次性失效。
func ConfirmRegisterVerify(scene, code string) (openid string, err error) {
	row, err := GetVerifyCode(scene)
	if err != nil {
		return "", err
	}
	if row.BindType != WechatBindTypeRegister {
		return "", ErrSceneInvalid
	}
	switch row.Status {
	case models.WechatVerifyStatusWaiting:
		return "", ErrSceneNotScanned
	case models.WechatVerifyStatusUsed:
		return "", ErrCodeUsed
	case models.WechatVerifyStatusExpired:
		return "", ErrCodeExpired
	}
	if strings.TrimSpace(code) != row.Code {
		return "", ErrCodeNotPending
	}
	now := time.Now()
	if _, uerr := models.Orm.QueryTable(new(models.WechatMpVerifyCode)).
		Filter("id", row.ID).
		Filter("status", models.WechatVerifyStatusScanned).
		Update(map[string]interface{}{"status": models.WechatVerifyStatusUsed, "update_time": now}); uerr != nil {
		return "", uerr
	}
	return row.OpenID, nil
}

// CreateRegisterOpenIDVerify 公众号内发送「注册」时创建的注册会话：
// openid 已知（消息发送者），网页端按验证码核销（无带参二维码的兜底路径）。
func CreateRegisterOpenIDVerify(openid string, ttl time.Duration) (*models.WechatMpVerifyCode, error) {
	openid = strings.TrimSpace(openid)
	if openid == "" {
		return nil, errors.New("openid 为空")
	}
	if ttl <= 0 {
		ttl = DefaultVerifyTTL
	}
	now := time.Now()
	expireAt := now.Add(ttl)
	row := &models.WechatMpVerifyCode{
		Scene:      randomScene(),
		Code:       randomCode6(),
		OpenID:     openid,
		Status:     models.WechatVerifyStatusScanned, // 微信号已知，等同「已扫码待核销」
		BindType:   WechatBindTypeRegister,
		ExpireAt:   &expireAt,
		CreateTime: now,
		UpdateTime: &now,
	}
	if _, err := models.Orm.Insert(row); err != nil {
		return nil, err
	}
	return row, nil
}

// LatestPendingRegisterVerifyByOpenID 该微信号最近一条未核销的注册会话（重发验证码时复用）
func LatestPendingRegisterVerifyByOpenID(openid string) (*models.WechatMpVerifyCode, error) {
	var row models.WechatMpVerifyCode
	err := models.Orm.QueryTable(new(models.WechatMpVerifyCode)).
		Filter("openid", openid).
		Filter("bind_type", WechatBindTypeRegister).
		Filter("status", models.WechatVerifyStatusScanned).
		Filter("expire_at__gt", time.Now()).
		OrderBy("-id").
		One(&row)
	if err != nil {
		return nil, err
	}
	return &row, nil
}

// ConfirmRegisterVerifyByCode 无二维码兜底：按验证码认领「公众号发起」的注册会话。
// 只认领 bind_type=register、openid 非空、已扫码待核销的最近会话，CAS 核销防止重复使用。
func ConfirmRegisterVerifyByCode(code string) (string, error) {
	code = strings.TrimSpace(code)
	if code == "" {
		return "", ErrCodeNotPending
	}
	var row models.WechatMpVerifyCode
	err := models.Orm.QueryTable(new(models.WechatMpVerifyCode)).
		Filter("code", code).
		Filter("bind_type", WechatBindTypeRegister).
		Filter("openid__ne", "").
		Filter("status", models.WechatVerifyStatusScanned).
		Filter("expire_at__gt", time.Now()).
		OrderBy("-id").
		One(&row)
	if err != nil {
		return "", ErrCodeNotPending
	}
	now := time.Now()
	affected, uerr := models.Orm.QueryTable(new(models.WechatMpVerifyCode)).
		Filter("id", row.ID).
		Filter("status", models.WechatVerifyStatusScanned).
		Update(map[string]interface{}{"status": models.WechatVerifyStatusUsed, "update_time": now})
	if uerr != nil {
		return "", uerr
	}
	if affected == 0 {
		return "", ErrCodeUsed
	}
	return row.OpenID, nil
}