//go:build mysql
// +build mysql

package mysql

import (
	"database/sql"
	"errors"
	"time"

	t "github.com/tinode/chat/server/store/types"
)

func (a *adapter) routedLoginLockoutAdapter(id t.TenantID) (*adapter, error) {
	if err := validTenant(id); err != nil {
		return nil, err
	}
	if a.tenantScopedDB {
		return a, nil
	}
	tenantAdp, err := a.routedTenantAdapter(id)
	if err != nil {
		return nil, err
	}
	return tenantAdp, nil
}

type loginLockoutRow struct {
	ID             int64         `db:"id"`
	UserID         sql.NullInt64 `db:"user_id"`
	AccountHash    string        `db:"account_hash"`
	FailedAttempts int           `db:"failed_attempts"`
	WindowStartAt  sql.NullTime  `db:"window_started_at"`
	LockedUntil    sql.NullTime  `db:"locked_until"`
	LastAttemptAt  sql.NullTime  `db:"last_attempt_at"`
	UpdatedAt      sql.NullTime  `db:"updated_at"`
}

func loginLockoutFromRow(id t.TenantID, row loginLockoutRow) *t.LoginLockout {
	out := &t.LoginLockout{
		TenantID:       id,
		ID:             row.ID,
		AccountHash:    row.AccountHash,
		FailedAttempts: row.FailedAttempts,
	}
	if row.UserID.Valid {
		out.UserID = row.UserID.Int64
	}
	if row.WindowStartAt.Valid {
		v := row.WindowStartAt.Time
		out.WindowStartAt = &v
	}
	if row.LockedUntil.Valid {
		v := row.LockedUntil.Time
		out.LockedUntil = &v
	}
	if row.LastAttemptAt.Valid {
		v := row.LastAttemptAt.Time
		out.LastAttemptAt = &v
	}
	if row.UpdatedAt.Valid {
		v := row.UpdatedAt.Time
		out.UpdatedAt = &v
	}
	return out
}

const loginLockoutColumns = `id,user_id,account_hash,failed_attempts,window_started_at,locked_until,last_attempt_at,updated_at`

// TenantLoginLockoutGet reads the lockout counter for the given account hash.
func (a *adapter) TenantLoginLockoutGet(id t.TenantID, accountHash string) (*t.LoginLockout, error) {
	tenantAdp, err := a.routedLoginLockoutAdapter(id)
	if err != nil {
		return nil, err
	}
	if tenantAdp != a {
		return tenantAdp.TenantLoginLockoutGet(id, accountHash)
	}
	if accountHash == "" {
		return nil, t.ErrMalformed
	}
	ctx, cancel := a.getContext()
	if cancel != nil {
		defer cancel()
	}
	var row loginLockoutRow
	err = a.db.GetContext(ctx, &row,
		`SELECT `+loginLockoutColumns+` FROM im_login_lockouts WHERE account_hash=?`, accountHash)
	if errors.Is(err, sql.ErrNoRows) {
		return nil, t.ErrNotFound
	}
	if err != nil {
		return nil, err
	}
	return loginLockoutFromRow(id, row), nil
}

// TenantLoginLockoutRecordFailure atomically inserts or increments the failure
// counter. windowCutoff is "now minus window seconds": an older window start
// resets the counter to 1. The updated row is returned to the caller.
func (a *adapter) TenantLoginLockoutRecordFailure(id t.TenantID, accountHash string, userID *int64, windowCutoff, now time.Time) (*t.LoginLockout, error) {
	tenantAdp, err := a.routedLoginLockoutAdapter(id)
	if err != nil {
		return nil, err
	}
	if tenantAdp != a {
		return tenantAdp.TenantLoginLockoutRecordFailure(id, accountHash, userID, windowCutoff, now)
	}
	if accountHash == "" || now.IsZero() {
		return nil, t.ErrMalformed
	}
	ctx, cancel := a.getContext()
	if cancel != nil {
		defer cancel()
	}
	rowID, err := nextSnowflakeID()
	if err != nil {
		return nil, err
	}
	// MySQL evaluates ON DUPLICATE KEY UPDATE assignments left to right, so
	// failed_attempts is recomputed before window_started_at is overwritten.
	_, err = a.db.ExecContext(ctx, `INSERT INTO im_login_lockouts
		(id,user_id,account_hash,failed_attempts,window_started_at,last_attempt_at)
		VALUES(?,?,?,1,?,?)
		ON DUPLICATE KEY UPDATE
		  failed_attempts = IF(window_started_at IS NULL OR window_started_at < ?, 1, failed_attempts + 1),
		  window_started_at = IF(window_started_at IS NULL OR window_started_at < ?, ?, window_started_at),
		  last_attempt_at = ?,
		  user_id = COALESCE(user_id, ?)`,
		rowID, userID, accountHash, now, now,
		windowCutoff, windowCutoff, now, now, userID)
	if err != nil {
		return nil, err
	}
	var row loginLockoutRow
	err = a.db.GetContext(ctx, &row,
		`SELECT `+loginLockoutColumns+` FROM im_login_lockouts WHERE account_hash=?`, accountHash)
	if err != nil {
		return nil, err
	}
	return loginLockoutFromRow(id, row), nil
}

// TenantLoginLockoutLock sets locked_until unless a newer lock already covers now.
func (a *adapter) TenantLoginLockoutLock(id t.TenantID, accountHash string, lockedUntil, now time.Time) error {
	tenantAdp, err := a.routedLoginLockoutAdapter(id)
	if err != nil {
		return err
	}
	if tenantAdp != a {
		return tenantAdp.TenantLoginLockoutLock(id, accountHash, lockedUntil, now)
	}
	if accountHash == "" || lockedUntil.IsZero() || now.IsZero() {
		return t.ErrMalformed
	}
	ctx, cancel := a.getContext()
	if cancel != nil {
		defer cancel()
	}
	_, err = a.db.ExecContext(ctx,
		`UPDATE im_login_lockouts SET locked_until=?, updated_at=? WHERE account_hash=? AND (locked_until IS NULL OR locked_until < ?)`,
		lockedUntil, now, accountHash, now)
	return err
}

// TenantLoginLockoutReset removes the counter after a successful login.
func (a *adapter) TenantLoginLockoutReset(id t.TenantID, accountHash string) error {
	tenantAdp, err := a.routedLoginLockoutAdapter(id)
	if err != nil {
		return err
	}
	if tenantAdp != a {
		return tenantAdp.TenantLoginLockoutReset(id, accountHash)
	}
	if accountHash == "" {
		return t.ErrMalformed
	}
	ctx, cancel := a.getContext()
	if cancel != nil {
		defer cancel()
	}
	_, err = a.db.ExecContext(ctx, `DELETE FROM im_login_lockouts WHERE account_hash=?`, accountHash)
	return err
}

// TenantLoginLockoutRelease clears the lock and zeroes the counter (admin unlock).
func (a *adapter) TenantLoginLockoutRelease(id t.TenantID, accountHash string, now time.Time) error {
	tenantAdp, err := a.routedLoginLockoutAdapter(id)
	if err != nil {
		return err
	}
	if tenantAdp != a {
		return tenantAdp.TenantLoginLockoutRelease(id, accountHash, now)
	}
	if accountHash == "" || now.IsZero() {
		return t.ErrMalformed
	}
	ctx, cancel := a.getContext()
	if cancel != nil {
		defer cancel()
	}
	_, err = a.db.ExecContext(ctx,
		`UPDATE im_login_lockouts SET failed_attempts=0, window_started_at=NULL, locked_until=NULL, updated_at=? WHERE account_hash=?`,
		now, accountHash)
	return err
}