package resumable

import (
	"context"
	"errors"
	"github.com/Tencent/WeKnora/internal/types"
	"time"
)

const MaxFileSize int64 = 20 << 30
const ChunkSize int64 = 4 << 20
const UserQuota int64 = 40 << 30
const TenantQuota int64 = 100 << 30
const MaxActive = 20

var ErrInvalid = errors.New("上传参数或校验和无效")
var ErrConflict = errors.New("上传状态或分块偏移已变化，请刷新后继续")
var ErrQuota = errors.New("上传暂存配额不足，请取消其他上传或等待过期清理")
var ErrForbidden = errors.New("没有此上传或目标资源的权限")

// UserError contains only an intentionally public explanation written by the
// upload implementation. Driver, filesystem and provider errors are never
// promoted to this type and remain confined to server logs.
type UserError string

func (e UserError) Error() string { return string(e) }

func publicError(err error) string {
	var public UserError
	if errors.As(err, &public) {
		return public.Error()
	}
	var input *types.DigitalHumanInputError
	if errors.As(err, &input) {
		return input.Error()
	}
	for _, sentinel := range []error{ErrInvalid, ErrConflict, ErrQuota, ErrForbidden} {
		if errors.Is(err, sentinel) {
			return sentinel.Error()
		}
	}
	return "文件处理暂不可用，请稍后重试或联系管理员检查服务日志"
}

type Upload struct {
	ID           string     `json:"id" gorm:"primaryKey;type:varchar(36)"`
	TenantID     uint64     `json:"-" gorm:"index"`
	OwnerID      string     `json:"-" gorm:"type:varchar(36);index"`
	Kind         string     `json:"kind"`
	TargetID     string     `json:"target_id"`
	Name         string     `json:"name"`
	Size         int64      `json:"size"`
	Offset       int64      `json:"offset"`
	ChunkSize    int64      `json:"chunk_size"`
	SHA256       string     `json:"sha256"`
	Fingerprint  string     `json:"fingerprint"`
	State        string     `json:"state" gorm:"index"`
	Error        string     `json:"error,omitempty"`
	Options      types.JSON `json:"options" gorm:"type:jsonb"`
	Result       types.JSON `json:"result,omitempty" gorm:"type:jsonb"`
	IngestOffset int64      `json:"ingest_offset"`
	Part         int        `json:"part"`
	ExpiresAt    time.Time  `json:"expires_at" gorm:"index"`
	LeaseUntil   *time.Time `json:"-"`
	LeaseToken   string     `json:"-"`
	CreatedAt    time.Time  `json:"created_at"`
	UpdatedAt    time.Time  `json:"updated_at"`
}

func (Upload) TableName() string { return "resumable_uploads" }

type Chunk struct {
	UploadID string `json:"-" gorm:"primaryKey;type:varchar(36)"`
	Offset   int64  `json:"offset" gorm:"primaryKey"`
	Size     int64  `json:"size"`
	SHA256   string `json:"sha256"`
}

func (Chunk) TableName() string { return "resumable_upload_chunks" }

type CreateInput struct {
	Kind        string     `json:"kind"`
	TargetID    string     `json:"target_id"`
	Name        string     `json:"name"`
	Size        int64      `json:"size"`
	SHA256      string     `json:"sha256"`
	Fingerprint string     `json:"fingerprint"`
	Options     types.JSON `json:"options"`
}

// Import processes one bounded unit, returning a durable checkpoint. The worker
// renews the lease around each unit and never queues the entire file at once.
type ImportFunc func(context.Context, *Upload, string) (offset int64, result types.JSON, done bool, err error)
type ContextFunc func(context.Context, *Upload) (context.Context, error)
type AuthorizeFunc func(context.Context, string, string) error