package mysql

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

	"github.com/pkg/errors"

	"github.com/usememos/memos/store"
)

func (d *DB) CreateUser(ctx context.Context, create *store.User) (*store.User, error) {
	result, err := insertUser(ctx, d.db, create)
	if err != nil {
		return nil, err
	}

	id, err := result.LastInsertId()
	if err != nil {
		return nil, err
	}

	id32 := int32(id)
	list, err := d.ListUsers(ctx, &store.FindUser{ID: &id32})
	if err != nil {
		return nil, err
	}
	if len(list) != 1 {
		return nil, errors.Errorf("unexpected user count: %d", len(list))
	}

	return list[0], nil
}

func (d *DB) UpdateUser(ctx context.Context, update *store.UpdateUser) (*store.User, error) {
	tx, err := d.db.BeginTx(ctx, nil)
	if err != nil {
		return nil, err
	}
	defer func() { _ = tx.Rollback() }()
	if update.RowStatus != nil && *update.RowStatus == store.Archived {
		if err := validateMySQLUserArchive(ctx, tx, update.ID); err != nil {
			return nil, err
		}
	}
	set, args := []string{}, []any{}
	if v := update.UpdatedTs; v != nil {
		set, args = append(set, "`updated_ts` = FROM_UNIXTIME(?)"), append(args, *v)
	}
	if v := update.RowStatus; v != nil {
		set, args = append(set, "`row_status` = ?"), append(args, *v)
	}
	if v := update.Username; v != nil {
		set, args = append(set, "`username` = ?"), append(args, *v)
	}
	if v := update.Email; v != nil {
		set, args = append(set, "`email` = ?"), append(args, *v)
	}
	if v := update.Nickname; v != nil {
		set, args = append(set, "`nickname` = ?"), append(args, *v)
	}
	if v := update.AvatarURL; v != nil {
		set, args = append(set, "`avatar_url` = ?"), append(args, *v)
	}
	if v := update.PasswordHash; v != nil {
		set, args = append(set, "`password_hash` = ?"), append(args, *v)
	}
	if v := update.Description; v != nil {
		set, args = append(set, "`description` = ?"), append(args, *v)
	}
	if v := update.Role; v != nil {
		set, args = append(set, "`role` = ?"), append(args, *v)
	}
	args = append(args, update.ID)

	query := "UPDATE `user` SET " + strings.Join(set, ", ") + " WHERE `id` = ?"
	if _, err := tx.ExecContext(ctx, query, args...); err != nil {
		return nil, err
	}
	user := &store.User{}
	if err := tx.QueryRowContext(ctx, `SELECT id, username, role, email, nickname, password_hash, avatar_url, description,
		UNIX_TIMESTAMP(created_ts), UNIX_TIMESTAMP(updated_ts), row_status FROM user WHERE id = ?`, update.ID).Scan(
		&user.ID, &user.Username, &user.Role, &user.Email, &user.Nickname, &user.PasswordHash, &user.AvatarURL,
		&user.Description, &user.CreatedTs, &user.UpdatedTs, &user.RowStatus,
	); err != nil {
		return nil, err
	}
	if err := tx.Commit(); err != nil {
		return nil, err
	}
	return user, nil
}

func validateMySQLUserArchive(ctx context.Context, tx *sql.Tx, userID int32) error {
	var current store.RowStatus
	if err := tx.QueryRowContext(ctx, "SELECT row_status FROM user WHERE id = ?", userID).Scan(&current); err != nil {
		return err
	}
	if current != store.Normal {
		return nil
	}
	var wouldLoseAdmin bool
	if err := tx.QueryRowContext(ctx, `SELECT EXISTS(
		SELECT 1 FROM space_member target
		JOIN space s ON s.id = target.space_id
		WHERE target.user_id = ? AND target.status = 'ACTIVE' AND target.role = 'ADMIN'
		AND NOT EXISTS (
			SELECT 1 FROM space_member other JOIN user u ON u.id = other.user_id
			WHERE other.space_id = target.space_id AND other.user_id <> ?
			AND other.status = 'ACTIVE' AND other.role = 'ADMIN' AND u.row_status = 'NORMAL'
		))`, userID, userID).Scan(&wouldLoseAdmin); err != nil {
		return err
	}
	if wouldLoseAdmin {
		return store.ErrLastSpaceAdmin
	}
	return nil
}

func (d *DB) ListUsers(ctx context.Context, find *store.FindUser) ([]*store.User, error) {
	where, args := []string{"1 = 1"}, []any{}
	orderBy := []string{"`created_ts` DESC", "`row_status` DESC", "`id` DESC"}

	if len(find.Filters) > 0 {
		return nil, errors.Errorf("user filters are not supported")
	}

	if v := find.ID; v != nil {
		where, args = append(where, "`id` = ?"), append(args, *v)
	}
	if len(find.IDList) > 0 {
		placeholders := make([]string, 0, len(find.IDList))
		for range find.IDList {
			placeholders = append(placeholders, "?")
		}
		where, args = append(where, fmt.Sprintf("`id` IN (%s)", strings.Join(placeholders, ", "))), append(args, func() []any {
			list := make([]any, 0, len(find.IDList))
			for _, id := range find.IDList {
				list = append(list, id)
			}
			return list
		}()...)
	}
	if len(find.UsernameList) > 0 {
		placeholders := make([]string, 0, len(find.UsernameList))
		for range find.UsernameList {
			placeholders = append(placeholders, "?")
		}
		where, args = append(where, fmt.Sprintf("`username` IN (%s)", strings.Join(placeholders, ", "))), append(args, func() []any {
			list := make([]any, 0, len(find.UsernameList))
			for _, username := range find.UsernameList {
				list = append(list, username)
			}
			return list
		}()...)
	}
	if v := find.RowStatus; v != nil {
		where, args = append(where, "`row_status` = ?"), append(args, *v)
	}
	if v := find.Username; v != nil {
		where, args = append(where, "`username` = ?"), append(args, *v)
	}
	if v := find.Role; v != nil {
		where, args = append(where, "`role` = ?"), append(args, *v)
	}
	if v := find.Email; v != nil {
		where, args = append(where, "`email` = ?"), append(args, *v)
	}
	if v := find.Nickname; v != nil {
		where, args = append(where, "`nickname` = ?"), append(args, *v)
	}
	if v := find.Search; v != nil && strings.TrimSpace(*v) != "" {
		query := strings.ToLower(strings.TrimSpace(*v))
		where, args = append(where, "(LOWER(`username`) LIKE ? OR LOWER(`nickname`) LIKE ?)"), append(args, "%"+query+"%", "%"+query+"%")
		orderBy = []string{
			"CASE WHEN LOWER(`username`) = ? THEN 0 WHEN LOWER(`username`) LIKE ? THEN 1 WHEN LOWER(`nickname`) LIKE ? THEN 2 ELSE 3 END",
			"CHAR_LENGTH(`username`) ASC",
			"`created_ts` DESC",
			"`row_status` DESC",
		}
		args = append(args, query, query+"%", query+"%")
	}
	query := "SELECT `id`, `username`, `role`, `email`, `nickname`, `password_hash`, `avatar_url`, `description`, UNIX_TIMESTAMP(`created_ts`), UNIX_TIMESTAMP(`updated_ts`), `row_status` FROM `user` WHERE " + strings.Join(where, " AND ") + " ORDER BY " + strings.Join(orderBy, ", ")
	if v := find.Limit; v != nil {
		query += fmt.Sprintf(" LIMIT %d", *v)
		if v := find.Offset; v != nil {
			query += fmt.Sprintf(" OFFSET %d", *v)
		}
	}
	rows, err := d.db.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	list := make([]*store.User, 0)
	for rows.Next() {
		var user store.User
		if err := rows.Scan(
			&user.ID,
			&user.Username,
			&user.Role,
			&user.Email,
			&user.Nickname,
			&user.PasswordHash,
			&user.AvatarURL,
			&user.Description,
			&user.CreatedTs,
			&user.UpdatedTs,
			&user.RowStatus,
		); err != nil {
			return nil, err
		}
		list = append(list, &user)
	}

	if err := rows.Err(); err != nil {
		return nil, err
	}

	return list, nil
}

func (d *DB) GetUser(ctx context.Context, find *store.FindUser) (*store.User, error) {
	list, err := d.ListUsers(ctx, find)
	if err != nil {
		return nil, err
	}
	if len(list) != 1 {
		return nil, errors.Errorf("unexpected user count: %d", len(list))
	}
	return list[0], nil
}