package ports

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

	"galaxy/gamemaster/internal/domain/engineversion"
)

//go:generate go run go.uber.org/mock/mockgen -destination=../adapters/mocks/mock_engineversionstore.go -package=mocks galaxy/gamemaster/internal/ports EngineVersionStore

// EngineVersionStore stores the engine version registry rows used by
// Game Lobby's start flow and by GM's admin patch and registry CRUD
// surface. Adapters must preserve domain semantics:
//
//   - Get returns engineversion.ErrNotFound when no row exists for
//     version.
//   - List with a nil status filter returns every row; with a non-nil
//     filter, only rows whose status matches are returned.
//   - Insert installs a fresh row and returns engineversion.ErrConflict
//     when a row with the same `version` already exists. Adapters
//     surface PostgreSQL unique violations through that sentinel so
//     the service layer maps them to a `conflict` REST envelope.
//   - Update applies a partial update; only fields whose pointer is
//     non-nil are mutated. The `updated_at` column is always refreshed
//     from input.Now.
//   - Deprecate sets `status=deprecated` for an existing version with
//     `updated_at = now`. It returns engineversion.ErrNotFound when no
//     row exists. The call is idempotent: deprecating an already
//     deprecated row succeeds with no further mutation.
//   - Delete removes the row identified by version. Returns
//     engineversion.ErrNotFound when no row matches. The service layer
//     gates Delete behind an explicit IsReferencedByActiveRuntime probe
//     so referenced rows surface engineversion.ErrInUse before the
//     adapter is touched; adapters do not enforce that guard themselves.
//   - IsReferencedByActiveRuntime reports whether any non-finished
//     `runtime_records` row currently references the version through
//     `current_engine_version`.
type EngineVersionStore interface {
	// Get returns the row identified by version. Returns
	// engineversion.ErrNotFound when no row exists.
	Get(ctx context.Context, version string) (engineversion.EngineVersion, error)

	// List returns every row whose status matches statusFilter when
	// non-nil, or every row when nil. The order is adapter-defined.
	List(ctx context.Context, statusFilter *engineversion.Status) ([]engineversion.EngineVersion, error)

	// Insert installs record into the registry.
	Insert(ctx context.Context, record engineversion.EngineVersion) error

	// Update applies a partial update to the row identified by
	// input.Version. Only fields whose pointer is non-nil are mutated.
	// Returns engineversion.ErrNotFound when no row exists.
	Update(ctx context.Context, input UpdateEngineVersionInput) error

	// Deprecate sets `status=deprecated` for version and refreshes
	// `updated_at` from now. Returns engineversion.ErrNotFound when no
	// row exists. Calling Deprecate on an already-deprecated row
	// succeeds with no mutation (idempotent).
	Deprecate(ctx context.Context, version string, now time.Time) error

	// Delete removes the row identified by version. Returns
	// engineversion.ErrNotFound when no row matches. Adapters do not
	// inspect runtime references; the service layer probes
	// IsReferencedByActiveRuntime first and surfaces
	// engineversion.ErrInUse independently.
	Delete(ctx context.Context, version string) error

	// IsReferencedByActiveRuntime reports whether any non-finished
	// runtime row currently references version through
	// `current_engine_version`. Used by the registry hard-delete path
	// to surface engineversion.ErrInUse.
	IsReferencedByActiveRuntime(ctx context.Context, version string) (bool, error)
}

// UpdateEngineVersionInput stores the arguments required to PATCH one
// engine version row. Pointer fields communicate «leave alone» (nil)
// vs. «write the value» (non-nil). At least one optional field must be
// set; otherwise the call is a no-op and Validate rejects it.
type UpdateEngineVersionInput struct {
	// Version identifies the row to mutate.
	Version string

	// ImageRef is the new image reference. Nil leaves the column
	// unchanged; non-nil must be non-empty.
	ImageRef *string

	// Options is the new options document (raw JSON). Nil leaves the
	// column unchanged; non-nil writes the value verbatim.
	Options *[]byte

	// Status is the new status. Nil leaves the column unchanged;
	// non-nil must be a known status.
	Status *engineversion.Status

	// Now stores the wall-clock used to refresh the `updated_at`
	// column on every successful update.
	Now time.Time
}

// Validate reports whether input contains a structurally valid PATCH
// request. Adapters call Validate before touching the store.
func (input UpdateEngineVersionInput) Validate() error {
	if strings.TrimSpace(input.Version) == "" {
		return fmt.Errorf("update engine version: version must not be empty")
	}
	if input.ImageRef == nil && input.Options == nil && input.Status == nil {
		return fmt.Errorf("update engine version: at least one field must be set")
	}
	if input.ImageRef != nil && strings.TrimSpace(*input.ImageRef) == "" {
		return fmt.Errorf(
			"update engine version: image ref must not be empty when set",
		)
	}
	if input.Status != nil && !input.Status.IsKnown() {
		return fmt.Errorf(
			"update engine version: status %q is unsupported",
			*input.Status,
		)
	}
	if input.Now.IsZero() {
		return fmt.Errorf("update engine version: now must not be zero")
	}
	return nil
}