package jobs

import (
	"context"
	"crypto/md5"
	"encoding/hex"
	"errors"
	"io"
	"os"
	"os/exec"
	"path"
	"path/filepath"
	"strings"
	"time"

	"quyun/v2/app/jobs/args"
	"quyun/v2/database/fields"
	"quyun/v2/database/models"
	"quyun/v2/pkg/consts"
	"quyun/v2/providers/storage"

	"github.com/riverqueue/river"
	log "github.com/sirupsen/logrus"
	"go.ipao.vip/gen/types"
	"gorm.io/gorm"
)

// @provider(job)
type MediaProcessWorker struct {
	river.WorkerDefaults[args.MediaAssetProcessJob]
	storage *storage.Storage
}

func (j *MediaProcessWorker) Work(ctx context.Context, job *river.Job[args.MediaAssetProcessJob]) error {
	arg := job.Args
	// 1. 获取媒体资源，保证租户隔离。
	tbl, q := models.MediaAssetQuery.QueryContext(ctx)
	q = q.Where(tbl.ID.Eq(arg.AssetID))
	if arg.TenantID > 0 {
		q = q.Where(tbl.TenantID.Eq(arg.TenantID))
	}
	asset, err := q.First()
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			log.Warnf("media asset not found: %d", arg.AssetID)
			return river.JobCancel(err)
		}
		return err
	}

	if asset.Status == consts.MediaAssetStatusReady || asset.Status == consts.MediaAssetStatusDeleted {
		return nil
	}

	// 2. 更新状态为处理中，标识处理已开始。
	if err := models.MediaAssetQuery.WithContext(ctx).
		UnderlyingDB().
		Model(&models.MediaAsset{}).
		Where("id = ?", asset.ID).
		Updates(map[string]any{
			"status":     consts.MediaAssetStatusProcessing,
			"updated_at": time.Now(),
		}).Error; err != nil {
		return err
	}

	finalStatus := consts.MediaAssetStatusReady

	// 3. 处理视频（FFmpeg，未安装时走模拟流程）。
	if asset.Type == consts.MediaAssetTypeVideo {
		if strings.ToLower(asset.Provider) == "local" {
			localPath := j.storage.Config.LocalPath
			if localPath == "" {
				localPath = "./storage"
			}
			inputFile := filepath.Join(localPath, asset.ObjectKey)
			if _, err := os.Stat(inputFile); err != nil {
				log.Errorf("media file missing: %s, err=%v", inputFile, err)
				finalStatus = consts.MediaAssetStatusFailed
			} else if _, err := exec.LookPath("ffmpeg"); err != nil {
				log.Warn("ffmpeg not found, skipping real transcoding")
			} else {
				outputDir := filepath.Dir(inputFile)
				coverTempKey := asset.ObjectKey + ".jpg"
				coverFile := filepath.Join(outputDir, filepath.Base(coverTempKey))

				// 生成封面，作为后续管线的占位输出。
				cmd := exec.CommandContext(
					ctx,
					"ffmpeg",
					"-y",
					"-i",
					inputFile,
					"-ss",
					"00:00:01.000",
					"-vframes",
					"1",
					coverFile,
				)
				if out, err := cmd.CombinedOutput(); err != nil {
					log.Errorf("ffmpeg failed: %s, output: %s", err, string(out))
					finalStatus = consts.MediaAssetStatusFailed
				} else {
					log.Infof("Generated cover: %s", coverFile)
					// 生成封面资产记录，便于后台可追踪产物。
					if err := j.registerCoverAsset(ctx, asset, coverFile); err != nil {
						log.Errorf("register cover failed: %s", err)
						finalStatus = consts.MediaAssetStatusFailed
					}
				}
			}
		} else {
			log.Warn("non-local provider, skipping ffmpeg processing")
		}
	}

	// 4. 更新最终状态。
	if err := models.MediaAssetQuery.WithContext(ctx).
		UnderlyingDB().
		Model(&models.MediaAsset{}).
		Where("id = ?", asset.ID).
		Updates(map[string]any{
			"status":     finalStatus,
			"updated_at": time.Now(),
		}).Error; err != nil {
		return err
	}
	return nil
}

func (j *MediaProcessWorker) registerCoverAsset(ctx context.Context, asset *models.MediaAsset, coverFile string) error {
	if asset == nil || coverFile == "" {
		return nil
	}
	if _, err := os.Stat(coverFile); err != nil {
		return err
	}

	// 已存在封面派生资产时直接跳过。
	tbl, q := models.MediaAssetQuery.QueryContext(ctx)
	existing, err := q.Where(
		tbl.SourceAssetID.Eq(asset.ID),
		tbl.Type.Eq(consts.MediaAssetTypeImage),
	).First()
	if err == nil && existing != nil {
		return nil
	}
	if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
		return err
	}

	hash, size, err := fileMD5(coverFile)
	if err != nil {
		return err
	}

	var tenant *models.Tenant
	if asset.TenantID > 0 {
		tenant, err = models.TenantQuery.WithContext(ctx).
			Where(models.TenantQuery.ID.Eq(asset.TenantID)).
			First()
		if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
			return err
		}
	}

	filename := asset.Meta.Data().Filename
	if filename == "" {
		filename = filepath.Base(asset.ObjectKey)
	}
	coverName := coverFilename(filename)
	objectKey := buildObjectKey(tenant, hash, coverName)

	// 本地存储将文件移动到目标 objectKey 位置，保持路径规范。
	localPath := j.storage.Config.LocalPath
	if localPath == "" {
		localPath = "./storage"
	}
	dstPath := filepath.Join(localPath, filepath.FromSlash(objectKey))
	if coverFile != dstPath {
		if err := os.MkdirAll(filepath.Dir(dstPath), 0o755); err != nil {
			return err
		}
		if _, err := os.Stat(dstPath); err == nil {
			_ = os.Remove(coverFile)
		} else if err := os.Rename(coverFile, dstPath); err != nil {
			return err
		}
	}

	coverAsset := &models.MediaAsset{
		TenantID:      asset.TenantID,
		UserID:        asset.UserID,
		Type:          consts.MediaAssetTypeImage,
		Status:        consts.MediaAssetStatusReady,
		Provider:      asset.Provider,
		Bucket:        asset.Bucket,
		ObjectKey:     objectKey,
		Hash:          hash,
		Variant:       consts.MediaAssetVariantMain,
		SourceAssetID: asset.ID,
		Meta: types.NewJSONType(fields.MediaAssetMeta{
			Filename: coverName,
			Size:     size,
		}),
	}
	if err := models.MediaAssetQuery.WithContext(ctx).Create(coverAsset); err != nil {
		return err
	}
	return nil
}

func coverFilename(filename string) string {
	base := strings.TrimSuffix(filename, filepath.Ext(filename))
	if base == "" {
		base = "cover"
	}
	return base + "_cover.jpg"
}

func buildObjectKey(tenant *models.Tenant, hash, filename string) string {
	// 按租户维度组织对象路径：quyun/<tenant_uuid>/<hash>.<ext>
	tenantUUID := "public"
	if tenant != nil && tenant.UUID.String() != "" {
		tenantUUID = tenant.UUID.String()
	}
	ext := strings.ToLower(filepath.Ext(filename))
	return path.Join("quyun", tenantUUID, hash+ext)
}

func fileMD5(filename string) (string, int64, error) {
	f, err := os.Open(filename)
	if err != nil {
		return "", 0, err
	}
	defer f.Close()

	h := md5.New()
	size, err := io.Copy(h, f)
	if err != nil {
		return "", size, err
	}
	return hex.EncodeToString(h.Sum(nil)), size, nil
}