package ports

import (
	"context"
	"fmt"
	"strings"
	"time"

	"galaxy/lobby/internal/domain/application"
	"galaxy/lobby/internal/domain/common"
)

// ApplicationStore stores application records and their secondary indexes.
// Adapters are responsible for maintaining the per-game set, per-user set,
// and the single-active lookup key together with the record.
type ApplicationStore interface {
	// Save persists a new submitted application record. The adapter must
	// enforce the single-active constraint — only one non-rejected
	// application per (applicant_user_id, game_id) pair may exist at a
	// time — and return application.ErrConflict if the constraint is
	// violated. Save rejects records whose status is not submitted.
	Save(ctx context.Context, record application.Application) error

	// Get returns the record identified by applicationID. It returns
	// application.ErrNotFound when no record exists.
	Get(ctx context.Context, applicationID common.ApplicationID) (application.Application, error)

	// GetByGame returns every application attached to gameID. The order
	// is adapter-defined; callers may reorder as needed.
	GetByGame(ctx context.Context, gameID common.GameID) ([]application.Application, error)

	// GetByUser returns every application submitted by applicantUserID.
	// The order is adapter-defined; callers may reorder as needed.
	GetByUser(ctx context.Context, applicantUserID string) ([]application.Application, error)

	// UpdateStatus applies one status transition in a compare-and-swap
	// fashion. The adapter must first call application.Transition to
	// reject invalid pairs without touching the store; on success it must
	// verify that the current status equals input.ExpectedFrom, update
	// the primary record, and clear the single-active lookup key when
	// transitioning to rejected. Adapters set DecidedAt to input.At.
	UpdateStatus(ctx context.Context, input UpdateApplicationStatusInput) error
}

// UpdateApplicationStatusInput stores the arguments required to apply one
// status transition through an ApplicationStore.
type UpdateApplicationStatusInput struct {
	// ApplicationID identifies the record to mutate.
	ApplicationID common.ApplicationID

	// ExpectedFrom stores the status the caller believes the record
	// currently has. A mismatch results in application.ErrConflict.
	ExpectedFrom application.Status

	// To stores the destination status.
	To application.Status

	// At stores the wall-clock used for DecidedAt.
	At time.Time
}

// Validate reports whether input contains a structurally valid status
// transition request.
func (input UpdateApplicationStatusInput) Validate() error {
	if err := input.ApplicationID.Validate(); err != nil {
		return fmt.Errorf("update application status: application id: %w", err)
	}
	if !input.ExpectedFrom.IsKnown() {
		return fmt.Errorf(
			"update application status: expected from status %q is unsupported",
			input.ExpectedFrom,
		)
	}
	if !input.To.IsKnown() {
		return fmt.Errorf(
			"update application status: to status %q is unsupported",
			input.To,
		)
	}
	if input.At.IsZero() {
		return fmt.Errorf("update application status: at must not be zero")
	}
	return nil
}

// NormalizedApplicantUserID trims surrounding whitespace so adapter
// keyspace lookups match the form the domain persists.
func NormalizedApplicantUserID(userID string) string {
	return strings.TrimSpace(userID)
}