// Package evidence defines the narrow internal screenshot contract shared by HTTP and storage.
package evidence

import (
	"context"
	"errors"
	"io"
	"time"

	"cmbuyer/admin/internal/deviceauth"
)

const (
	KindSKUPanelGate1        = "SKU_PANEL_GATE_1"
	PrivacyInternalRaw       = "INTERNAL_RAW"
	PNGContentType           = "image/png"
	MaxFileBytes       int64 = 10 << 20
	MaxImageSide             = 8192
	MaxImagePixels           = 16_777_216
)

var (
	ErrInvalid  = errors.New("invalid evidence")
	ErrConflict = errors.New("evidence upload key conflict")
	ErrNotFound = errors.New("evidence not found")
	ErrTooLarge = errors.New("evidence file too large")
)

type UploadMetadata struct {
	UploadKey   string
	TaskID      string
	AttemptID   string
	Kind        string
	PrivacyTier string
	SHA256      string
	CapturedAt  time.Time
}

// StagedFile contains only server-generated state. Multipart filenames and client paths never enter this type.
type StagedFile struct {
	Path        string
	SHA256      string
	ByteSize    int64
	ContentType string
	Width       int
	Height      int
}

type Asset struct {
	ID                 string    `json:"asset_id"`
	TaskID             string    `json:"task_id"`
	AttemptID          string    `json:"attempt_id"`
	Kind               string    `json:"kind"`
	PrivacyTier        string    `json:"privacy_tier"`
	SHA256             string    `json:"sha256"`
	ByteSize           int64     `json:"byte_size"`
	ContentType        string    `json:"content_type"`
	Width              int       `json:"width_px"`
	Height             int       `json:"height_px"`
	CapturedAt         time.Time `json:"captured_at"`
	UploadedByDeviceID string    `json:"-"`
	StorageKey         string    `json:"-"`
	CreatedAt          time.Time `json:"-"`
}

// Store separates bounded multipart staging from metadata commit so field order cannot weaken validation.
type Store interface {
	Stage(io.Reader, string) (StagedFile, error)
	Discard(StagedFile)
	Commit(context.Context, deviceauth.Principal, UploadMetadata, StagedFile) (Asset, bool, error)
	Open(context.Context, string) (Asset, io.ReadSeekCloser, error)
}