package handlers

import (
	"context"
	"crypto/rand"
	"encoding/hex"
	"fmt"
	"time"

	"rag/file-system/internal/domain/model"
	"rag/file-system/internal/domain/repository"

	"github.com/google/uuid"
)

type CreateShareCommand struct {
	ResourceType string
	ResourceID   string
	Password     *string
	ExpiresAt    *time.Time
	MaxDownloads *int
	CreatedBy    string
}

type DeleteShareCommand struct {
	ShareID   string
	CreatedBy string
}

type CreateShareHandler struct {
	ShareRepo repository.ShareRepository
}

func NewCreateShareHandler(shareRepo repository.ShareRepository) *CreateShareHandler {
	return &CreateShareHandler{ShareRepo: shareRepo}
}

func (h *CreateShareHandler) Handle(ctx context.Context, cmd CreateShareCommand) (*model.ShareLink, error) {
	token, err := generateShareToken()
	if err != nil {
		return nil, fmt.Errorf("failed to generate token: %w", err)
	}

	share := &model.ShareLink{
		ID:            uuid.New().String(),
		ResourceType:  cmd.ResourceType,
		ResourceID:    cmd.ResourceID,
		Token:         token,
		Password:      cmd.Password,
		ExpiresAt:     cmd.ExpiresAt,
		DownloadCount: 0,
		MaxDownloads:  cmd.MaxDownloads,
		CreatedBy:     cmd.CreatedBy,
		CreatedAt:     time.Now(),
	}

	if err := h.ShareRepo.Create(ctx, share); err != nil {
		return nil, err
	}
	return share, nil
}

type DeleteShareHandler struct {
	ShareRepo repository.ShareRepository
}

func NewDeleteShareHandler(shareRepo repository.ShareRepository) *DeleteShareHandler {
	return &DeleteShareHandler{ShareRepo: shareRepo}
}

func (h *DeleteShareHandler) Handle(ctx context.Context, cmd DeleteShareCommand) (string, error) {
	if err := h.ShareRepo.Delete(ctx, cmd.ShareID, cmd.CreatedBy); err != nil {
		return "", err
	}
	return "分享已取消", nil
}

func generateShareToken() (string, error) {
	b := make([]byte, 16)
	if _, err := rand.Read(b); err != nil {
		return "", err
	}
	return hex.EncodeToString(b), nil
}