package mysql

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

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

// 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) {
	user, err := r.queryUser(ctx, r.db, "WHERE user_id = ?", userID)
	if err == sql.ErrNoRows {
		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) {
	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 user_id, default_display_user_id, current_display_user_id, current_display_user_id_kind, COALESCE(current_display_user_id_expires_at_ms, 0), status, created_at_ms, updated_at_ms
		FROM users
		WHERE user_id IN (%s)
	`, strings.Join(placeholders, ",")), args...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	result := make(map[int64]userdomain.User, len(userIDs))
	for rows.Next() {
		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 {
	tx, err := r.db.BeginTx(ctx, nil)
	if err != nil {
		return err
	}
	defer tx.Rollback()

	if err := insertUserIdentity(ctx, tx, user, identity); err != nil {
		return mapDuplicateError(err)
	}

	return tx.Commit()
}

// 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) {
	row := q.QueryRowContext(ctx, `
		SELECT user_id, default_display_user_id, current_display_user_id, current_display_user_id_kind, COALESCE(current_display_user_id_expires_at_ms, 0), status, created_at_ms, updated_at_ms
		FROM users
		`+clause, args...)

	return scanUser(row)
}

// scanUser 固定 users 投影到领域模型的转换，并补齐迁移窗口中的默认值。
func scanUser(scanner interface {
	Scan(dest ...any) error
}) (userdomain.User, error) {
	var user userdomain.User
	var status string
	var kind string
	err := scanner.Scan(&user.UserID, &user.DefaultDisplayUserID, &user.CurrentDisplayUserID, &kind, &user.CurrentDisplayUserIDExpiresAtMs, &status, &user.CreatedAtMs, &user.UpdatedAtMs)
	if err != nil {
		return userdomain.User{}, err
	}

	user.Status = userdomain.Status(status)
	user.CurrentDisplayUserIDKind = userdomain.DisplayUserIDKind(kind)
	return user.NormalizeDisplayUserIDState(), 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 {
	user = user.NormalizeDisplayUserIDState()
	if user.DefaultDisplayUserID == "" {
		user.DefaultDisplayUserID = identity.DisplayUserID
	}
	if user.CurrentDisplayUserID == "" {
		user.CurrentDisplayUserID = identity.DisplayUserID
	}
	if user.CurrentDisplayUserIDKind == "" {
		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, status, created_at_ms, updated_at_ms)
		VALUES (?, ?, ?, ?, NULL, ?, ?, ?)
	`, user.UserID, user.DefaultDisplayUserID, user.CurrentDisplayUserID, string(user.CurrentDisplayUserIDKind), 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)
	return err
}