// Package store defines persistence for the domain entities. The interface
// exists so that the query implementation can be swapped (a different SQL
// dialect, or an in-memory fake in tests) without touching the service layer.
package store

import (
	"context"
	"errors"

	"go-places-api/internal/domain"
	"go-places-api/internal/geo"
)

var (
	// ErrNotFound is returned when a lookup matches no row.
	ErrNotFound = errors.New("not found")
	// ErrConflict is returned when a unique constraint would be violated.
	ErrConflict = errors.New("conflict")
)

// ImageFilter narrows a picture search.
type ImageFilter struct {
	// PlaceID restricts results to one place when non-empty.
	PlaceID string
	// CreatorID restricts results to one author when non-empty.
	CreatorID string
	// Within restricts results to pictures inside this box and radius. A nil
	// Coordinate disables the geographic restriction.
	Within *NearbyQuery
	// Limit caps the number of rows. Zero means unlimited.
	Limit int
	// Offset skips rows for pagination.
	Offset int
}

// NearbyQuery selects entities within a radius of a point.
type NearbyQuery struct {
	Center       domain.Coordinate
	RadiusMeters float64
}

// Store is the persistence contract required by the service layer.
type Store interface {
	// CreatePlace inserts a place and returns it as persisted.
	CreatePlace(ctx context.Context, p domain.Place) (domain.Place, error)
	// GetPlace loads a place, its pictures, comments and author.
	GetPlace(ctx context.Context, id string) (domain.Place, error)
	// UpdatePlace replaces the mutable fields of a place.
	UpdatePlace(ctx context.Context, p domain.Place) (domain.Place, error)
	// ListPlaces returns places newest first.
	ListPlaces(ctx context.Context, limit, offset int) ([]domain.Place, error)
	// DeletePlace removes a place and everything attached to it.
	DeletePlace(ctx context.Context, id string) error

	// CreateImage inserts a picture record.
	CreateImage(ctx context.Context, img domain.Image) (domain.Image, error)
	// GetImage loads one picture.
	GetImage(ctx context.Context, id string) (domain.Image, error)
	// GetImageByStorageKey loads the picture a blob key belongs to. The media
	// route needs it to learn the declared content type and size of a stored
	// object without trusting the file's own bytes.
	GetImageByStorageKey(ctx context.Context, key string) (domain.Image, error)
	// UpdateImage replaces the mutable fields of a picture.
	UpdateImage(ctx context.Context, img domain.Image) (domain.Image, error)
	// ListImages returns pictures matching the filter, newest first.
	ListImages(ctx context.Context, f ImageFilter) ([]domain.Image, error)
	// ImagesWithin returns pictures whose capture point lies inside the radius.
	ImagesWithin(ctx context.Context, q NearbyQuery) ([]domain.Image, error)
	// ReplaceBadges swaps the badge set for a picture.
	ReplaceBadges(ctx context.Context, imageID string, badges []domain.Badge) error
	// CreateImageLink records that two pictures were taken at the same place.
	// Re-recording the same pair updates the measured distance.
	CreateImageLink(ctx context.Context, imageID, relatedImageID string, distanceMeters float64, reason string) error
	// ListImageLinks returns the recorded links for a picture in both
	// directions, so a link is visible from either end.
	ListImageLinks(ctx context.Context, imageID string) ([]domain.Link, error)
	// SetAnalysisState records the outcome of the analysis pipeline.
	SetAnalysisState(ctx context.Context, imageID string, status domain.AnalysisStatus, failure string) error
	// DeleteImage removes a picture and its badges.
	DeleteImage(ctx context.Context, id string) error

	// AddComment inserts a comment and returns it as persisted.
	AddComment(ctx context.Context, c domain.Comment) (domain.Comment, error)
	// ListComments returns the comments on a place, oldest first.
	ListComments(ctx context.Context, placeID string) ([]domain.Comment, error)

	// UpsertUser stores the identity asserted by the auth layer.
	UpsertUser(ctx context.Context, u domain.User) error
	// GetUser loads a user by identifier.
	GetUser(ctx context.Context, id string) (domain.User, error)

	// Close releases resources held by the store.
	Close() error
}

// BoundingBox converts a nearby query into the coarse window used to pre-filter
// rows in SQL. Exposed here so implementations and tests agree on the filter.
func (q NearbyQuery) BoundingBox() geo.BoundingBox {
	return geo.Around(q.Center, q.RadiusMeters)
}

// ErrInvalidInput is returned when a write would violate a domain rule, such as
// linking a picture to itself.
var ErrInvalidInput = errors.New("invalid input")

// ImageGetter is the optional extra surface the service uses for storage-key
// lookups. It is separate from Store so an implementation that cannot map a key
// back to a record simply does not satisfy it.
type ImageGetter interface {
	GetImageByStorageKey(ctx context.Context, key string) (domain.Image, error)
}

// Pinger is the optional extra surface used by the readiness probe.
type Pinger interface {
	Ping(ctx context.Context) error
}