types

type ChunkStatus int

type DownloadConfig struct {
	URL                string
	OutputPath         string
	DestPath           string // Full destination path (for resume state lookup)
	ID                 string
	Filename           string
	IsResume           bool // True if this is explicitly a resume, not a fresh download
	ProgressCh         chan<- any
	State              *ProgressState
	SavedState         *DownloadState    // Pre-loaded state for resume optimization
	Runtime            *RuntimeConfig    // Dynamic settings from user config
	Mirrors            []string          // List of mirror URLs (including primary)
	Headers            map[string]string // Custom HTTP headers to include in download requests
	IsExplicitCategory bool              // Used to override category routing from TUI
	TotalSize          int64             // Total size in bytes of the required download
	SupportsRange      bool              // Indicates whether the server supports range requests for concurrency
}

type DownloadEntry struct {
	ID          string   `json:"id"`       // Unique ID of the download
	URLHash     string   `json:"url_hash"` // Hash of URL only (backward compatibility)
	URL         string   `json:"url"`
	DestPath    string   `json:"dest_path"`
	Filename    string   `json:"filename"`
	Status      string   `json:"status"`       // "paused", "completed", "error"
	TotalSize   int64    `json:"total_size"`   // File size in bytes
	Downloaded  int64    `json:"downloaded"`   // Bytes downloaded
	CompletedAt int64    `json:"completed_at"` // Unix timestamp when completed
	TimeTaken   int64    `json:"time_taken"`   // Duration in milliseconds (for completed)
	AvgSpeed    float64  `json:"avg_speed"`    // Average speed in bytes/sec (for completed)
	Mirrors     []string `json:"mirrors,omitempty"`
}

type DownloadState struct {
	ID         string   `json:"id"`       // Unique ID of the download
	URLHash    string   `json:"url_hash"` // Hash of URL only (for master list compatibility)
	URL        string   `json:"url"`
	DestPath   string   `json:"dest_path"`
	TotalSize  int64    `json:"total_size"`
	Downloaded int64    `json:"downloaded"`
	Tasks      []Task   `json:"tasks"` // Remaining tasks
	Filename   string   `json:"filename"`
	CreatedAt  int64    `json:"created_at"` // Unix timestamp
	PausedAt   int64    `json:"paused_at"`  // Unix timestamp
	Elapsed    int64    `json:"elapsed"`    // Elapsed time in nanoseconds
	Mirrors    []string `json:"mirrors,omitempty"`

	// Bitmap state
	ChunkBitmap     []byte `json:"chunk_bitmap,omitempty"`
	ActualChunkSize int64  `json:"actual_chunk_size,omitempty"`

	// Integrity verification
	FileHash string `json:"file_hash,omitempty"` // SHA-256 hash of the .surge file at pause time
}

type DownloadStatus struct {
	ID          string  `json:"id"`
	URL         string  `json:"url"`
	Filename    string  `json:"filename"`
	DestPath    string  `json:"dest_path,omitempty"` // Full absolute path to file
	TotalSize   int64   `json:"total_size"`
	Downloaded  int64   `json:"downloaded"`
	Progress    float64 `json:"progress"` // Percentage 0-100
	Speed       float64 `json:"speed"`    // MB/s
	Status      string  `json:"status"`   // "queued", "paused", "downloading", "completed", "error"
	Error       string  `json:"error,omitempty"`
	ETA         int64   `json:"eta"`         // Estimated seconds remaining
	Connections int     `json:"connections"` // Active connections
	AddedAt     int64   `json:"added_at"`    // Unix timestamp when added
	TimeTaken   int64   `json:"time_taken"`  // Duration in milliseconds (completed only)
	AvgSpeed    float64 `json:"avg_speed"`   // Average speed in bytes/sec (completed only)
}

type MasterList struct {
	Downloads []DownloadEntry `json:"downloads"`
}

type MirrorStatus struct {
	URL    string
	Active bool
	Error  bool
}

type ProgressState struct {
	ID            string
	Downloaded    atomic.Int64
	TotalSize     int64
	DestPath      string // Initial destination path
	Filename      string // Initial filename
	URL           string // Source URL
	StartTime     time.Time
	ActiveWorkers atomic.Int32
	Done          atomic.Bool
	Error         atomic.Pointer[error]
	Paused        atomic.Bool
	Pausing       atomic.Bool // Intermediate state: Pause requested but workers not yet exited

	VerifiedProgress  atomic.Int64  // Verified bytes written to disk (for UI progress)
	SessionStartBytes int64         // SessionStartBytes tracks how many bytes were already downloaded when the current session started
	SavedElapsed      time.Duration // Time spent in previous sessions

	Mirrors []MirrorStatus // Status of each mirror

	// Chunk Visualization (Bitmap)
	ChunkBitmap     []byte  // 2 bits per chunk
	ChunkProgress   []int64 // Bytes downloaded per chunk (runtime only, not persisted)
	ActualChunkSize int64   // Size of each actual chunk in bytes
	BitmapWidth     int     // Number of chunks tracked
	// contains filtered or unexported fields
}

type RuntimeConfig struct {
	MaxConnectionsPerHost int
	UserAgent             string
	ProxyURL              string
	SequentialDownload    bool
	MinChunkSize          int64

	WorkerBufferSize      int
	MaxTaskRetries        int
	SlowWorkerThreshold   float64
	SlowWorkerGracePeriod time.Duration
	StallTimeout          time.Duration
	SpeedEmaAlpha         float64
}

type Task struct {
	Offset          int64         `json:"offset"`
	Length          int64         `json:"length"`
	SharedMaxOffset *atomic.Int64 `json:"-"` // Used to deduplicate byte counting in hedged requests
}