// Package store abstracts the per_diem_rates storage so the HTTP layer can be
// tested without a real Postgres and so the Postgres backend can be swapped
// against an in-memory fake for dev loops.
package store

import (
	"context"
	"errors"
	"time"

	"basicstack.de/proofedmesh/services/admin-api/internal/model"
)

// ErrNotFound is returned by Get and Retire when the rate_id does not exist.
var ErrNotFound = errors.New("per_diem_rate: not found")

// ErrOverlap is returned by Create when the new rate would overlap an existing
// (country, city) range. Mirrors the Postgres EXCLUDE constraint.
var ErrOverlap = errors.New("per_diem_rate: overlaps an existing active range for (country, city)")

// ErrAlreadyRetired is returned by Retire when the rate is already retired
// (valid_to IS NOT NULL and in the past).
var ErrAlreadyRetired = errors.New("per_diem_rate: already retired")

// ListFilter narrows a List call. Zero value lists everything.
type ListFilter struct {
	Country    string // "" = any
	ActiveOnly bool   // if true, only rates with valid_to IS NULL or valid_to >= today
}

// RateStore is implemented by both the in-memory store (for tests + dev) and
// the Postgres store (for prod). All methods are side-effect-free apart from
// their obvious effect and all honour ctx cancellation.
type RateStore interface {
	List(ctx context.Context, f ListFilter) ([]model.Rate, error)
	Get(ctx context.Context, rateID string) (model.Rate, error)

	// Create inserts a new rate, returning the finalised row (rate_id is
	// assigned by the backend). The attestation ref is set later via
	// AttachAttestation when the Signing Service has produced it.
	Create(ctx context.Context, in model.NewRateInput, createdBy string, now time.Time) (model.Rate, error)

	// Retire sets valid_to on the rate; subsequent lookups by valid_on past
	// that date must not return it.
	Retire(ctx context.Context, rateID string, validTo time.Time, performedBy string, now time.Time) (model.Rate, error)

	// AttachAttestation attaches the signed attestation reference to a rate.
	// Called after Create or Retire once the Signing Service responded.
	AttachAttestation(ctx context.Context, rateID string, attestationRef string) error
}