"""
Data models for file-centric download system.
Each download record represents ONE file, not a batch.
"""

from pydantic import BaseModel
from typing import Optional
from datetime import datetime
from decimal import Decimal


class FileDownload(BaseModel):
    """Represents a single file download record in the database."""
    id: int
    batch_id: str
    
    # File info
    ge_id: str
    lang: str
    file_name: str
    file_path: str  # Relative path in source
    
    # Mode & status
    mode: str  # 'api' or 'sharing'
    status: str  # 'pending', 'downloading', 'completed', 'failed', 'cancelled'
    
    # Paths
    destination_path: Optional[str] = None
    
    # Progress
    file_size: Optional[int] = None
    downloaded_size: int = 0
    progress_percent: Decimal = Decimal('0.00')
    
    # Timestamps
    created_at: datetime
    started_at: Optional[datetime] = None
    completed_at: Optional[datetime] = None
    
    # Error handling
    error_message: Optional[str] = None
    retry_count: int = 0
    
    # Metadata
    sharing_id: Optional[str] = None
    mongodb_path: Optional[str] = None
    
    class Config:
        from_attributes = True  # For Pydantic v2 (orm_mode in v1)


# ==================== REQUEST MODELS ====================

class FileInfo(BaseModel):
    """Single file information for batch download requests."""
    name: str
    path: str  # Relative path in source
    isdir: bool = False  # For API mode
    is_folder: Optional[bool] = None  # For Sharing mode (alias)


class CreateDownloadBatchRequest(BaseModel):
    """
    Request to create a batch of file downloads (API mode).
    Each file will become a separate download record.
    """
    files: list[FileInfo]
    ge_id: str
    lang: str


class CreateSharingDownloadBatchRequest(BaseModel):
    """
    Request to create batch downloads from sharing link.
    """
    sharing_id: str
    files: list[FileInfo]
    ge_id: Optional[str] = None
    lang: Optional[str] = None


class UpdateDownloadRequest(BaseModel):
    """Request to update a single download (cancel/retry)."""
    action: str  # 'retry' or 'cancel'


# ==================== RESPONSE MODELS ====================

class DownloadBatchResponse(BaseModel):
    """Response after creating a batch of downloads."""
    success: bool
    batch_id: str
    file_count: int
    download_ids: list[int]  # List of created download IDs
    message: str


class DownloadResponse(BaseModel):
    """Response for single download operation."""
    success: bool
    download: Optional[FileDownload] = None
    message: str


class DownloadListResponse(BaseModel):
    """Response for listing downloads."""
    success: bool
    downloads: list[FileDownload]
    count: int


# ==================== BATCH GROUPING ====================

class DownloadBatch(BaseModel):
    """
    Grouped view of downloads for UI display.
    Groups files by batch_id for better UX.
    """
    batch_id: str
    ge_id: str
    lang: str
    mode: str
    
    # Batch-level stats
    total_files: int
    completed_files: int
    failed_files: int
    total_size: int
    downloaded_size: int
    
    # Batch status (derived from files)
    status: str  # 'downloading', 'completed', 'partial_failed', 'failed'
    
    # Timestamps (min/max from files)
    created_at: datetime
    started_at: Optional[datetime] = None
    completed_at: Optional[datetime] = None
    
    # Duration (if completed)
    duration_seconds: Optional[float] = None
    
    # Individual files in this batch
    files: list[FileDownload]