// Package mysql 实现 user-service 的 MySQL 持久化边界。
package mysql

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

	"hyapp/pkg/xerr"
	userdomain "hyapp/services/user-service/internal/domain/user"
)

const userSelectColumns = `
		user_id,
		default_display_user_id,
		current_display_user_id,
		current_display_user_id_kind,
		COALESCE(current_display_user_id_expires_at_ms, 0),
		COALESCE(username, ''),
		COALESCE(gender, ''),
		COALESCE(country, ''),
		COALESCE(region_id, 0),
		COALESCE((SELECT c.country_id FROM countries c WHERE c.country_code = users.country LIMIT 1), 0),
		COALESCE((SELECT c.country_name FROM countries c WHERE c.country_code = users.country LIMIT 1), ''),
		COALESCE((SELECT c.country_display_name FROM countries c WHERE c.country_code = users.country LIMIT 1), ''),
		COALESCE((SELECT c.iso_numeric FROM countries c WHERE c.country_code = users.country LIMIT 1), ''),
		COALESCE((SELECT c.phone_country_code FROM countries c WHERE c.country_code = users.country LIMIT 1), ''),
		COALESCE((SELECT c.enabled FROM countries c WHERE c.country_code = users.country LIMIT 1), 0),
		COALESCE((SELECT rg.region_code FROM regions rg WHERE rg.region_id = users.region_id LIMIT 1), ''),
		COALESCE((SELECT rg.name FROM regions rg WHERE rg.region_id = users.region_id LIMIT 1), ''),
		COALESCE(invite_code, ''),
		COALESCE(register_ip, ''),
		COALESCE(register_user_agent, ''),
		COALESCE(country_by_ip, ''),
		COALESCE(register_device_id, ''),
		COALESCE(register_device, ''),
		COALESCE(os_version, ''),
		COALESCE(avatar, ''),
		COALESCE(DATE_FORMAT(birth_date, '%Y-%m-%d'), ''),
		COALESCE(app_version, ''),
		COALESCE(build_number, ''),
		COALESCE(source, ''),
		COALESCE(install_channel, ''),
		COALESCE(campaign, ''),
		COALESCE(platform, ''),
		COALESCE(language, ''),
		COALESCE(timezone, ''),
		COALESCE(profile_completed, 0),
		COALESCE(profile_completed_at_ms, 0),
		COALESCE(onboarding_status, 'profile_required'),
		status,
		created_at_ms,
		updated_at_ms`

// GetUser 从 users 表读取用户主状态；调用方负责按业务时钟触发懒过期。
func (r *Repository) GetUser(ctx context.Context, userID int64) (userdomain.User, error) {
	// 普通查询不加锁，靓号过期恢复由 service 层判断后调用 identity 事务。
	user, err := r.queryUser(ctx, r.db, "WHERE user_id = ?", userID)
	if err == sql.ErrNoRows {
		// users 表无记录时返回稳定 NotFound。
		return userdomain.User{}, xerr.New(xerr.NotFound, "user not found")
	}
	if err != nil {
		return userdomain.User{}, err
	}

	return user, nil
}

// BatchGetUsers 批量读取用户主状态，缺失用户不会出现在返回 map 中。
func (r *Repository) BatchGetUsers(ctx context.Context, userIDs []int64) (map[int64]userdomain.User, error) {
	// 调用方已校验 userIDs 非空且合法，这里直接构造 IN 查询。
	placeholders := make([]string, 0, len(userIDs))
	args := make([]any, 0, len(userIDs))
	for _, userID := range userIDs {
		placeholders = append(placeholders, "?")
		args = append(args, userID)
	}

	rows, err := r.db.QueryContext(ctx, fmt.Sprintf(`
		SELECT %s
		FROM users
		WHERE user_id IN (%s)
	`, userSelectColumns, strings.Join(placeholders, ",")), args...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	result := make(map[int64]userdomain.User, len(userIDs))
	for rows.Next() {
		// 缺失用户不会返回，调用方按 map key 判断存在性。
		user, err := scanUser(rows)
		if err != nil {
			return nil, err
		}
		result[user.UserID] = user
	}

	return result, rows.Err()
}

// CreateUserWithIdentity 是用户创建的事务入口。
// 它同时写 users 和默认短号 active 记录，避免出现没有默认门牌号的用户。
func (r *Repository) CreateUserWithIdentity(ctx context.Context, user userdomain.User, identity userdomain.Identity) error {
	// 用户和默认短号必须在一个事务里创建，避免出现孤立用户。
	tx, err := r.db.BeginTx(ctx, nil)
	if err != nil {
		return err
	}
	defer tx.Rollback()

	if err := insertUserIdentity(ctx, tx, user, identity); err != nil {
		// 唯一键冲突转换成 display_user_id exists，供 service 有限重试。
		return mapDuplicateError(err)
	}

	return tx.Commit()
}

// UpdateUserProfile 修改用户基础资料并返回更新后的 users 快照。
func (r *Repository) UpdateUserProfile(ctx context.Context, command userdomain.ProfileUpdateCommand) (userdomain.User, error) {
	// 资料更新锁定 users 行，避免和国家修改、短号懒过期覆盖 updated_at_ms。
	tx, err := r.db.BeginTx(ctx, nil)
	if err != nil {
		return userdomain.User{}, err
	}
	defer tx.Rollback()

	user, err := r.queryUser(ctx, tx, "WHERE user_id = ? FOR UPDATE", command.UserID)
	if err == sql.ErrNoRows {
		return userdomain.User{}, xerr.New(xerr.NotFound, "user not found")
	}
	if err != nil {
		return userdomain.User{}, err
	}
	if command.Username != nil {
		user.Username = *command.Username
	}
	if command.Avatar != nil {
		user.Avatar = *command.Avatar
	}
	if command.BirthDate != nil {
		user.BirthDate = *command.BirthDate
	}
	user.UpdatedAtMs = command.UpdatedAtMs

	_, err = tx.ExecContext(ctx, `
		UPDATE users
		SET username = ?, avatar = ?, birth_date = ?, updated_at_ms = ?
		WHERE user_id = ?
	`, nullableString(user.Username), nullableString(user.Avatar), nullableString(user.BirthDate), user.UpdatedAtMs, command.UserID)
	if err != nil {
		return userdomain.User{}, err
	}
	if err := tx.Commit(); err != nil {
		return userdomain.User{}, err
	}

	return user, nil
}

// CompleteOnboarding 是注册页资料固化的事务入口。
// 该方法不写 user_country_change_logs，确保首次国家选择不消耗改国家冷却窗口。
func (r *Repository) CompleteOnboarding(ctx context.Context, command userdomain.CompleteOnboardingCommand) (userdomain.User, error) {
	tx, err := r.db.BeginTx(ctx, nil)
	if err != nil {
		return userdomain.User{}, err
	}
	defer tx.Rollback()

	user, err := r.queryUser(ctx, tx, "WHERE user_id = ? FOR UPDATE", command.UserID)
	if err == sql.ErrNoRows {
		return userdomain.User{}, xerr.New(xerr.NotFound, "user not found")
	}
	if err != nil {
		return userdomain.User{}, err
	}
	if user.ProfileCompleted {
		// 已完成用户不能用注册页接口重写资料；提交入口保持幂等只返回当前事实。
		if err := tx.Commit(); err != nil {
			return userdomain.User{}, err
		}
		return r.GetUser(ctx, command.UserID)
	}

	_, err = tx.ExecContext(ctx, `
		UPDATE users
		SET username = ?,
			avatar = ?,
			country = ?,
			region_id = ?,
			profile_completed = ?,
			profile_completed_at_ms = ?,
			onboarding_status = ?,
			updated_at_ms = ?
		WHERE user_id = ?
	`, command.Username, command.Avatar, command.Country, nullableRegionID(command.RegionID), true, command.CompletedAtMs, string(userdomain.OnboardingStatusCompleted), command.CompletedAtMs, command.UserID)
	if err != nil {
		return userdomain.User{}, err
	}
	if err := tx.Commit(); err != nil {
		return userdomain.User{}, err
	}

	return r.GetUser(ctx, command.UserID)
}

// ChangeUserCountry 修改国家并写日志；冷却期检查和日志写入必须在同一事务内完成。
func (r *Repository) ChangeUserCountry(ctx context.Context, command userdomain.CountryChangeCommand) (userdomain.User, int64, error) {
	tx, err := r.db.BeginTx(ctx, nil)
	if err != nil {
		return userdomain.User{}, 0, err
	}
	defer tx.Rollback()

	user, err := r.queryUser(ctx, tx, "WHERE user_id = ? FOR UPDATE", command.UserID)
	if err == sql.ErrNoRows {
		return userdomain.User{}, 0, xerr.New(xerr.NotFound, "user not found")
	}
	if err != nil {
		return userdomain.User{}, 0, err
	}
	lastChangedAt, err := latestCountryChangedAt(ctx, tx, command.UserID)
	if err != nil {
		return userdomain.User{}, 0, err
	}
	nextAllowedAt := int64(0)
	if lastChangedAt > 0 && command.CooldownMs > 0 {
		nextAllowedAt = lastChangedAt + command.CooldownMs
	}
	if user.Country == command.NewCountry {
		// 修改为相同国家不写日志，也不消耗冷却期；映射变化时允许修正 stale region_id。
		if user.RegionID != command.NewRegionID {
			user.RegionID = command.NewRegionID
			user.UpdatedAtMs = command.ChangedAtMs
			if _, err := tx.ExecContext(ctx, `
				UPDATE users
				SET region_id = ?, updated_at_ms = ?
				WHERE user_id = ?
			`, nullableRegionID(user.RegionID), user.UpdatedAtMs, command.UserID); err != nil {
				return userdomain.User{}, 0, err
			}
		}
		if err := tx.Commit(); err != nil {
			return userdomain.User{}, 0, err
		}
		updated, err := r.GetUser(ctx, command.UserID)
		return updated, nextAllowedAt, err
	}
	if nextAllowedAt > 0 && command.ChangedAtMs < nextAllowedAt {
		return userdomain.User{}, nextAllowedAt, xerr.New(xerr.CountryChangeCooldown, "country change is cooling down")
	}

	oldCountry := user.Country
	user.Country = command.NewCountry
	user.RegionID = command.NewRegionID
	user.UpdatedAtMs = command.ChangedAtMs
	_, err = tx.ExecContext(ctx, `
		UPDATE users
		SET country = ?, region_id = ?, updated_at_ms = ?
		WHERE user_id = ?
	`, nullableString(user.Country), nullableRegionID(user.RegionID), user.UpdatedAtMs, command.UserID)
	if err != nil {
		return userdomain.User{}, 0, err
	}
	_, err = tx.ExecContext(ctx, `
		INSERT INTO user_country_change_logs (user_id, old_country, new_country, request_id, changed_at_ms)
		VALUES (?, ?, ?, ?, ?)
	`, command.UserID, nullableString(oldCountry), command.NewCountry, command.RequestID, command.ChangedAtMs)
	if err != nil {
		return userdomain.User{}, 0, err
	}
	if err := tx.Commit(); err != nil {
		return userdomain.User{}, 0, err
	}

	updated, err := r.GetUser(ctx, command.UserID)
	return updated, command.ChangedAtMs + command.CooldownMs, err
}

// queryUser 读取 users 快照字段；既服务普通查询，也服务 identity 事务中的 FOR UPDATE 读。
func (r *Repository) queryUser(ctx context.Context, q queryer, clause string, args ...any) (userdomain.User, error) {
	// clause 由本包内部固定拼接，不能接受外部原始 SQL。
	row := q.QueryRowContext(ctx, `
		SELECT `+userSelectColumns+`
		FROM users
		`+clause, args...)

	return scanUser(row)
}

// scanUser 固定 users 投影到领域模型的转换。
func scanUser(scanner interface {
	Scan(dest ...any) error
}) (userdomain.User, error) {
	// scanUser 是 users 表到领域模型的唯一转换点。
	var user userdomain.User
	var status string
	var kind string
	var onboardingStatus string
	err := scanner.Scan(
		&user.UserID,
		&user.DefaultDisplayUserID,
		&user.CurrentDisplayUserID,
		&kind,
		&user.CurrentDisplayUserIDExpiresAtMs,
		&user.Username,
		&user.Gender,
		&user.Country,
		&user.RegionID,
		&user.CountryID,
		&user.CountryName,
		&user.CountryDisplayName,
		&user.ISONumeric,
		&user.PhoneCountryCode,
		&user.CountryEnabled,
		&user.RegionCode,
		&user.RegionName,
		&user.InviteCode,
		&user.RegisterIP,
		&user.RegisterUserAgent,
		&user.CountryByIP,
		&user.RegisterDeviceID,
		&user.RegisterDevice,
		&user.RegisterOSVersion,
		&user.Avatar,
		&user.BirthDate,
		&user.RegisterAppVersion,
		&user.RegisterBuildNumber,
		&user.RegisterSource,
		&user.RegisterInstallChannel,
		&user.RegisterCampaign,
		&user.RegisterPlatform,
		&user.Language,
		&user.Timezone,
		&user.ProfileCompleted,
		&user.ProfileCompletedAtMs,
		&onboardingStatus,
		&status,
		&user.CreatedAtMs,
		&user.UpdatedAtMs,
	)
	if err != nil {
		return userdomain.User{}, err
	}

	user.Status = userdomain.Status(status)
	user.CurrentDisplayUserIDKind = userdomain.DisplayUserIDKind(kind)
	user.OnboardingStatus = userdomain.OnboardingStatus(onboardingStatus)
	if user.OnboardingStatus == "" {
		if user.ProfileCompleted {
			user.OnboardingStatus = userdomain.OnboardingStatusCompleted
		} else {
			user.OnboardingStatus = userdomain.OnboardingStatusProfileRequired
		}
	}
	return user, nil
}

// insertUserIdentity 是跨 auth/user 创建用户用例共享的事务片段。
// 它只在调用方已经开启事务后执行，避免 service 层手动拼跨表事务。
func insertUserIdentity(ctx context.Context, tx *sql.Tx, user userdomain.User, identity userdomain.Identity) error {
	// 调用方已开启事务，本函数只负责插入 users 和默认 active display_user_id。
	if user.DefaultDisplayUserID == "" {
		// 创建路径允许 user 中未预填默认短号，以同事务创建的 identity 为准。
		user.DefaultDisplayUserID = identity.DisplayUserID
	}
	if user.CurrentDisplayUserID == "" {
		user.CurrentDisplayUserID = identity.DisplayUserID
	}
	if user.CurrentDisplayUserIDKind == "" {
		// 新用户默认短号永远是 default kind。
		user.CurrentDisplayUserIDKind = userdomain.DisplayUserIDKindDefault
	}

	_, err := tx.ExecContext(ctx, `
		INSERT INTO users (
			user_id,
			default_display_user_id,
			current_display_user_id,
			current_display_user_id_kind,
			current_display_user_id_expires_at_ms,
			username,
			gender,
			country,
			region_id,
			invite_code,
			register_ip,
			register_user_agent,
			country_by_ip,
			register_device_id,
			register_device,
			os_version,
			avatar,
			birth_date,
			app_version,
			build_number,
			source,
			install_channel,
			campaign,
			platform,
			language,
			timezone,
			profile_completed,
			profile_completed_at_ms,
			onboarding_status,
			status,
			created_at_ms,
			updated_at_ms
		)
		VALUES (
			?, ?, ?, ?, NULL,
			?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?,
			?, ?, ?, ?, ?, ?
		)
	`, user.UserID, user.DefaultDisplayUserID, user.CurrentDisplayUserID, string(user.CurrentDisplayUserIDKind), nullableString(user.Username), nullableString(user.Gender), nullableString(user.Country), nullableRegionID(user.RegionID), nullableString(user.InviteCode), nullableString(user.RegisterIP), nullableString(user.RegisterUserAgent), nullableString(user.CountryByIP), nullableString(user.RegisterDeviceID), nullableString(user.RegisterDevice), nullableString(user.RegisterOSVersion), nullableString(user.Avatar), nullableString(user.BirthDate), nullableString(user.RegisterAppVersion), nullableString(user.RegisterBuildNumber), nullableString(user.RegisterSource), nullableString(user.RegisterInstallChannel), nullableString(user.RegisterCampaign), nullableString(user.RegisterPlatform), nullableString(user.Language), nullableString(user.Timezone), user.ProfileCompleted, user.ProfileCompletedAtMs, onboardingStatusForInsert(user), string(user.Status), user.CreatedAtMs, user.UpdatedAtMs)
	if err != nil {
		return err
	}

	_, err = tx.ExecContext(ctx, `
		INSERT INTO user_display_user_ids (display_user_id, user_id, display_user_id_kind, status, assigned_at_ms, activated_at_ms, created_at_ms, updated_at_ms)
		VALUES (?, ?, ?, ?, ?, ?, ?, ?)
	`, identity.DisplayUserID, user.UserID, string(userdomain.DisplayUserIDKindDefault), string(userdomain.DisplayUserIDStatusActive), user.CreatedAtMs, user.CreatedAtMs, user.CreatedAtMs, user.UpdatedAtMs)
	// user_display_user_ids 唯一约束保证默认短号不和 active/held/reserved/blocked 记录冲突。
	return err
}

func onboardingStatusForInsert(user userdomain.User) string {
	// 创建路径默认保持未完成状态；只有 CompleteOnboarding 能把状态固化为 completed。
	if user.OnboardingStatus != "" {
		return string(user.OnboardingStatus)
	}
	if user.ProfileCompleted {
		return string(userdomain.OnboardingStatusCompleted)
	}

	return string(userdomain.OnboardingStatusProfileRequired)
}

func latestCountryChangedAt(ctx context.Context, tx *sql.Tx, userID int64) (int64, error) {
	// users 行已 FOR UPDATE；按同一用户串行化后读取最新日志即可防止并发绕过冷却。
	var changedAtMs int64
	err := tx.QueryRowContext(ctx, `
		SELECT changed_at_ms
		FROM user_country_change_logs
		WHERE user_id = ?
		ORDER BY changed_at_ms DESC
		LIMIT 1
	`, userID).Scan(&changedAtMs)
	if err == sql.ErrNoRows {
		return 0, nil
	}
	if err != nil {
		return 0, err
	}

	return changedAtMs, nil
}