"""
Document Management API endpoints - QDROs, Templates, and General Documents
"""
from typing import List, Optional, Dict, Any
from fastapi import APIRouter, Depends, HTTPException, status, Query, UploadFile, File, Form, Request
from sqlalchemy.orm import Session, joinedload
from sqlalchemy import or_, func, and_, desc, asc, text
from datetime import date, datetime
import os
import uuid
import shutil

from app.database.base import get_db
from app.models.qdro import QDRO
from app.models.files import File as FileModel
from app.models.rolodex import Rolodex
from app.models.lookups import FormIndex, FormList, Footer, Employee
from app.models.user import User
from app.auth.security import get_current_user
from app.models.additional import Document
from app.core.logging import get_logger
from app.services.audit import audit_service

router = APIRouter()


# Pydantic schemas
from pydantic import BaseModel


class QDROBase(BaseModel):
    file_no: str
    version: str = "01"
    title: Optional[str] = None
    content: Optional[str] = None
    status: str = "DRAFT"
    created_date: Optional[date] = None
    approved_date: Optional[date] = None
    filed_date: Optional[date] = None
    participant_name: Optional[str] = None
    spouse_name: Optional[str] = None
    plan_name: Optional[str] = None
    plan_administrator: Optional[str] = None
    notes: Optional[str] = None


class QDROCreate(QDROBase):
    pass


class QDROUpdate(BaseModel):
    version: Optional[str] = None
    title: Optional[str] = None
    content: Optional[str] = None
    status: Optional[str] = None
    created_date: Optional[date] = None
    approved_date: Optional[date] = None
    filed_date: Optional[date] = None
    participant_name: Optional[str] = None
    spouse_name: Optional[str] = None
    plan_name: Optional[str] = None
    plan_administrator: Optional[str] = None
    notes: Optional[str] = None


class QDROResponse(QDROBase):
    id: int
    
    class Config:
        from_attributes = True


@router.get("/qdros/{file_no}", response_model=List[QDROResponse])
async def get_file_qdros(
    file_no: str,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Get QDROs for specific file"""
    qdros = db.query(QDRO).filter(QDRO.file_no == file_no).order_by(QDRO.version).all()
    return qdros


@router.get("/qdros/", response_model=List[QDROResponse])
async def list_qdros(
    skip: int = Query(0, ge=0),
    limit: int = Query(50, ge=1, le=200),
    status_filter: Optional[str] = Query(None),
    search: Optional[str] = Query(None),
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """List all QDROs with filtering"""
    query = db.query(QDRO)
    
    if status_filter:
        query = query.filter(QDRO.status == status_filter)
    
    if search:
        query = query.filter(
            or_(
                QDRO.file_no.contains(search),
                QDRO.title.contains(search),
                QDRO.participant_name.contains(search),
                QDRO.spouse_name.contains(search),
                QDRO.plan_name.contains(search)
            )
        )
    
    qdros = query.offset(skip).limit(limit).all()
    return qdros


@router.post("/qdros/", response_model=QDROResponse)
async def create_qdro(
    qdro_data: QDROCreate,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Create new QDRO"""
    qdro = QDRO(**qdro_data.model_dump())
    
    if not qdro.created_date:
        qdro.created_date = date.today()
    
    db.add(qdro)
    db.commit()
    db.refresh(qdro)
    
    return qdro


@router.get("/qdros/{file_no}/{qdro_id}", response_model=QDROResponse)
async def get_qdro(
    file_no: str,
    qdro_id: int,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Get specific QDRO"""
    qdro = db.query(QDRO).filter(
        QDRO.id == qdro_id,
        QDRO.file_no == file_no
    ).first()
    
    if not qdro:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="QDRO not found"
        )
    
    return qdro


@router.put("/qdros/{file_no}/{qdro_id}", response_model=QDROResponse)
async def update_qdro(
    file_no: str,
    qdro_id: int,
    qdro_data: QDROUpdate,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Update QDRO"""
    qdro = db.query(QDRO).filter(
        QDRO.id == qdro_id,
        QDRO.file_no == file_no
    ).first()
    
    if not qdro:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="QDRO not found"
        )
    
    # Update fields
    for field, value in qdro_data.model_dump(exclude_unset=True).items():
        setattr(qdro, field, value)
    
    db.commit()
    db.refresh(qdro)
    
    return qdro


@router.delete("/qdros/{file_no}/{qdro_id}")
async def delete_qdro(
    file_no: str,
    qdro_id: int,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Delete QDRO"""
    qdro = db.query(QDRO).filter(
        QDRO.id == qdro_id,
        QDRO.file_no == file_no
    ).first()
    
    if not qdro:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="QDRO not found"
        )
    
    db.delete(qdro)
    db.commit()
    
    return {"message": "QDRO deleted successfully"}


# Enhanced Document Management Endpoints

# Template Management Schemas
class TemplateBase(BaseModel):
    """Base template schema"""
    form_id: str
    form_name: str
    category: str = "GENERAL"
    content: str = ""
    variables: Optional[Dict[str, str]] = None

class TemplateCreate(TemplateBase):
    pass

class TemplateUpdate(BaseModel):
    form_name: Optional[str] = None
    category: Optional[str] = None
    content: Optional[str] = None
    variables: Optional[Dict[str, str]] = None

class TemplateResponse(TemplateBase):
    active: bool = True
    created_at: Optional[datetime] = None
    
    class Config:
        from_attributes = True

# Document Generation Schema
class DocumentGenerateRequest(BaseModel):
    """Request to generate document from template"""
    template_id: str
    file_no: str
    output_format: str = "PDF"  # PDF, DOCX, HTML
    variables: Optional[Dict[str, Any]] = None

class DocumentResponse(BaseModel):
    """Generated document response"""
    document_id: str
    file_name: str
    file_path: str
    size: int
    created_at: datetime

# Document Statistics
class DocumentStats(BaseModel):
    """Document system statistics"""
    total_templates: int
    total_qdros: int
    templates_by_category: Dict[str, int]
    recent_activity: List[Dict[str, Any]]


@router.get("/templates/", response_model=List[TemplateResponse])
async def list_templates(
    skip: int = Query(0, ge=0),
    limit: int = Query(50, ge=1, le=200),
    category: Optional[str] = Query(None),
    search: Optional[str] = Query(None),
    active_only: bool = Query(True),
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """List available document templates"""
    query = db.query(FormIndex)
    
    if active_only:
        query = query.filter(FormIndex.active == True)
    
    if category:
        query = query.filter(FormIndex.category == category)
    
    if search:
        query = query.filter(
            or_(
                FormIndex.form_name.contains(search),
                FormIndex.form_id.contains(search)
            )
        )
    
    templates = query.offset(skip).limit(limit).all()
    
    # Enhanced response with template content
    results = []
    for template in templates:
        template_lines = db.query(FormList).filter(
            FormList.form_id == template.form_id
        ).order_by(FormList.line_number).all()
        
        content = "\n".join([line.content or "" for line in template_lines])
        
        results.append({
            "form_id": template.form_id,
            "form_name": template.form_name,
            "category": template.category,
            "content": content,
            "active": template.active,
            "created_at": template.created_at,
            "variables": _extract_variables_from_content(content)
        })
    
    return results


@router.post("/templates/", response_model=TemplateResponse)
async def create_template(
    template_data: TemplateCreate,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Create new document template"""
    # Check if template already exists
    existing = db.query(FormIndex).filter(FormIndex.form_id == template_data.form_id).first()
    if existing:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Template with this ID already exists"
        )
    
    # Create form index entry
    form_index = FormIndex(
        form_id=template_data.form_id,
        form_name=template_data.form_name,
        category=template_data.category,
        active=True
    )
    db.add(form_index)
    
    # Create form content lines
    content_lines = template_data.content.split('\n')
    for i, line in enumerate(content_lines, 1):
        form_line = FormList(
            form_id=template_data.form_id,
            line_number=i,
            content=line
        )
        db.add(form_line)
    
    db.commit()
    db.refresh(form_index)
    
    return {
        "form_id": form_index.form_id,
        "form_name": form_index.form_name,
        "category": form_index.category,
        "content": template_data.content,
        "active": form_index.active,
        "created_at": form_index.created_at,
        "variables": template_data.variables or {}
    }


@router.get("/templates/{template_id}", response_model=TemplateResponse)
async def get_template(
    template_id: str,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Get specific template with content"""
    template = db.query(FormIndex).filter(FormIndex.form_id == template_id).first()
    
    if not template:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Template not found"
        )
    
    # Get template content
    template_lines = db.query(FormList).filter(
        FormList.form_id == template_id
    ).order_by(FormList.line_number).all()
    
    content = "\n".join([line.content or "" for line in template_lines])
    
    return {
        "form_id": template.form_id,
        "form_name": template.form_name,
        "category": template.category,
        "content": content,
        "active": template.active,
        "created_at": template.created_at,
        "variables": _extract_variables_from_content(content)
    }


@router.put("/templates/{template_id}", response_model=TemplateResponse)
async def update_template(
    template_id: str,
    template_data: TemplateUpdate,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Update document template"""
    template = db.query(FormIndex).filter(FormIndex.form_id == template_id).first()
    
    if not template:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Template not found"
        )
    
    # Update form index
    if template_data.form_name:
        template.form_name = template_data.form_name
    if template_data.category:
        template.category = template_data.category
    
    # Update content if provided
    if template_data.content is not None:
        # Delete existing content lines
        db.query(FormList).filter(FormList.form_id == template_id).delete()
        
        # Add new content lines
        content_lines = template_data.content.split('\n')
        for i, line in enumerate(content_lines, 1):
            form_line = FormList(
                form_id=template_id,
                line_number=i,
                content=line
            )
            db.add(form_line)
    
    db.commit()
    db.refresh(template)
    
    # Get updated content
    template_lines = db.query(FormList).filter(
        FormList.form_id == template_id
    ).order_by(FormList.line_number).all()
    
    content = "\n".join([line.content or "" for line in template_lines])
    
    return {
        "form_id": template.form_id,
        "form_name": template.form_name,
        "category": template.category,
        "content": content,
        "active": template.active,
        "created_at": template.created_at,
        "variables": _extract_variables_from_content(content)
    }


@router.delete("/templates/{template_id}")
async def delete_template(
    template_id: str,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Delete document template"""
    template = db.query(FormIndex).filter(FormIndex.form_id == template_id).first()
    
    if not template:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Template not found"
        )
    
    # Delete content lines
    db.query(FormList).filter(FormList.form_id == template_id).delete()
    
    # Delete template
    db.delete(template)
    db.commit()
    
    return {"message": "Template deleted successfully"}


@router.post("/generate/{template_id}")
async def generate_document(
    template_id: str,
    request: DocumentGenerateRequest,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Generate document from template"""
    # Get template
    template = db.query(FormIndex).filter(FormIndex.form_id == template_id).first()
    if not template:
        raise HTTPException(status_code=404, detail="Template not found")
    
    # Get file information
    file_obj = db.query(FileModel).options(
        joinedload(FileModel.owner)
    ).filter(FileModel.file_no == request.file_no).first()
    
    if not file_obj:
        raise HTTPException(status_code=404, detail="File not found")
    
    # Get template content
    template_lines = db.query(FormList).filter(
        FormList.form_id == template_id
    ).order_by(FormList.line_number).all()
    
    template_content = "\n".join([line.content or "" for line in template_lines])
    
    # Prepare merge variables
    merge_vars = {
        "FILE_NO": file_obj.file_no,
        "CLIENT_FIRST": file_obj.owner.first if file_obj.owner else "",
        "CLIENT_LAST": file_obj.owner.last if file_obj.owner else "",
        "CLIENT_FULL": f"{file_obj.owner.first or ''} {file_obj.owner.last}".strip() if file_obj.owner else "",
        "MATTER": file_obj.regarding or "",
        "OPENED": file_obj.opened.strftime("%B %d, %Y") if file_obj.opened else "",
        "ATTORNEY": file_obj.empl_num or "",
        "TODAY": date.today().strftime("%B %d, %Y")
    }
    
    # Add any custom variables from the request
    if request.variables:
        merge_vars.update(request.variables)
    
    # Perform variable substitution
    merged_content = _merge_template_variables(template_content, merge_vars)
    
    # Generate document file
    document_id = str(uuid.uuid4())
    file_name = f"{template.form_name}_{file_obj.file_no}_{date.today().isoformat()}"
    
    if request.output_format.upper() == "PDF":
        file_path = f"/app/exports/{document_id}.pdf"
        file_name += ".pdf"
        # Here you would implement PDF generation
        # For now, create a simple text file
        with open(f"/app/exports/{document_id}.txt", "w") as f:
            f.write(merged_content)
        file_path = f"/app/exports/{document_id}.txt"
    elif request.output_format.upper() == "DOCX":
        file_path = f"/app/exports/{document_id}.docx"
        file_name += ".docx"
        # Implement DOCX generation
        with open(f"/app/exports/{document_id}.txt", "w") as f:
            f.write(merged_content)
        file_path = f"/app/exports/{document_id}.txt"
    else:  # HTML
        file_path = f"/app/exports/{document_id}.html"
        file_name += ".html"
        html_content = f"<html><body><pre>{merged_content}</pre></body></html>"
        with open(file_path, "w") as f:
            f.write(html_content)
    
    file_size = os.path.getsize(file_path) if os.path.exists(file_path) else 0
    
    return {
        "document_id": document_id,
        "file_name": file_name,
        "file_path": file_path,
        "size": file_size,
        "created_at": datetime.now()
    }


@router.get("/categories/")
async def get_template_categories(
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Get available template categories"""
    categories = db.query(FormIndex.category).distinct().all()
    return [cat[0] for cat in categories if cat[0]]


@router.get("/stats/summary")
async def get_document_stats(
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Get document system statistics"""
    # Template statistics
    total_templates = db.query(FormIndex).filter(FormIndex.active == True).count()
    total_qdros = db.query(QDRO).count()
    
    # Templates by category
    category_stats = db.query(
        FormIndex.category,
        func.count(FormIndex.form_id)
    ).filter(FormIndex.active == True).group_by(FormIndex.category).all()
    
    categories_dict = {cat[0] or "Uncategorized": cat[1] for cat in category_stats}
    
    # Recent QDRO activity
    recent_qdros = db.query(QDRO).order_by(desc(QDRO.updated_at)).limit(5).all()
    recent_activity = [
        {
            "type": "QDRO",
            "file_no": qdro.file_no,
            "status": qdro.status,
            "updated_at": qdro.updated_at.isoformat() if qdro.updated_at else None
        }
        for qdro in recent_qdros
    ]
    
    return {
        "total_templates": total_templates,
        "total_qdros": total_qdros,
        "templates_by_category": categories_dict,
        "recent_activity": recent_activity
    }


@router.get("/file/{file_no}/documents")
async def get_file_documents(
    file_no: str,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Get all documents associated with a specific file"""
    # Get QDROs for this file
    qdros = db.query(QDRO).filter(QDRO.file_no == file_no).order_by(desc(QDRO.updated_at)).all()
    
    # Format response
    documents = [
        {
            "id": qdro.id,
            "type": "QDRO",
            "title": f"QDRO v{qdro.version}",
            "status": qdro.status,
            "created_date": qdro.created_date.isoformat() if qdro.created_date else None,
            "updated_at": qdro.updated_at.isoformat() if qdro.updated_at else None,
            "file_no": qdro.file_no
        }
        for qdro in qdros
    ]
    
    return {
        "file_no": file_no,
        "documents": documents,
        "total_count": len(documents)
    }


def _extract_variables_from_content(content: str) -> Dict[str, str]:
    """Extract variable placeholders from template content"""
    import re
    variables = {}
    
    # Find variables in format {{VARIABLE_NAME}}
    matches = re.findall(r'\{\{([^}]+)\}\}', content)
    for match in matches:
        var_name = match.strip()
        variables[var_name] = f"Placeholder for {var_name}"
    
    # Find variables in format ^VARIABLE
    matches = re.findall(r'\^([A-Z_]+)', content)
    for match in matches:
        variables[match] = f"Placeholder for {match}"
    
    return variables


def _merge_template_variables(content: str, variables: Dict[str, Any]) -> str:
    """Replace template variables with actual values"""
    merged = content
    
    # Replace {{VARIABLE}} format
    for var_name, value in variables.items():
        merged = merged.replace(f"{{{{{var_name}}}}}", str(value or ""))
        merged = merged.replace(f"^{var_name}", str(value or ""))
    
    return merged


# --- Client Error Logging (for Documents page) ---
class ClientErrorLog(BaseModel):
    """Payload for client-side error logging"""
    message: str
    action: Optional[str] = None
    stack: Optional[str] = None
    url: Optional[str] = None
    line: Optional[int] = None
    column: Optional[int] = None
    user_agent: Optional[str] = None
    extra: Optional[Dict[str, Any]] = None


@router.post("/client-error")
async def log_client_error(
    payload: ClientErrorLog,
    request: Request,
    db: Session = Depends(get_db),
    current_user: Optional[User] = Depends(lambda: None)
):
    """Accept client-side error logs from the Documents page.

    This endpoint is lightweight and safe to call; it records the error to the
    application logs and best-effort to the audit log without interrupting the UI.
    """
    logger = get_logger("client.documents")
    client_ip = request.headers.get("x-forwarded-for")
    if client_ip:
        client_ip = client_ip.split(",")[0].strip()
    else:
        client_ip = request.client.host if request.client else None

    logger.error(
        "Client error reported",
        action=payload.action,
        message=payload.message,
        stack=payload.stack,
        page="/documents",
        url=payload.url or str(request.url),
        line=payload.line,
        column=payload.column,
        user=getattr(current_user, "username", None),
        user_id=getattr(current_user, "id", None),
        user_agent=payload.user_agent or request.headers.get("user-agent"),
        client_ip=client_ip,
        extra=payload.extra,
    )

    # Best-effort audit log; do not raise on failure
    try:
        audit_service.log_action(
            db=db,
            action="CLIENT_ERROR",
            resource_type="DOCUMENTS",
            user=current_user,
            resource_id=None,
            details={
                "action": payload.action,
                "message": payload.message,
                "url": payload.url or str(request.url),
                "line": payload.line,
                "column": payload.column,
                "extra": payload.extra,
            },
            request=request,
        )
    except Exception:
        pass

    return {"status": "logged"}


@router.post("/upload/{file_no}")
async def upload_document(
    file_no: str,
    file: UploadFile = File(...),
    description: Optional[str] = Form(None),
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Upload a document to a file"""
    file_obj = db.query(FileModel).filter(FileModel.file_no == file_no).first()
    if not file_obj:
        raise HTTPException(status_code=404, detail="File not found")

    if not file.filename:
        raise HTTPException(status_code=400, detail="No file uploaded")

    allowed_types = [
        "application/pdf",
        "application/msword",
        "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
        "image/jpeg",
        "image/png"
    ]
    if file.content_type not in allowed_types:
        raise HTTPException(status_code=400, detail="Invalid file type")

    max_size = 10 * 1024 * 1024  # 10MB
    content = await file.read()
    if len(content) > max_size:
        raise HTTPException(status_code=400, detail="File too large")

    upload_dir = f"uploads/{file_no}"
    os.makedirs(upload_dir, exist_ok=True)

    ext = file.filename.split(".")[-1]
    unique_name = f"{uuid.uuid4()}.{ext}"
    path = f"{upload_dir}/{unique_name}"

    with open(path, "wb") as f:
        f.write(content)

    doc = Document(
        file_no=file_no,
        filename=file.filename,
        path=path,
        description=description,
        type=file.content_type,
        size=len(content),
        uploaded_by=current_user.username
    )
    db.add(doc)
    db.commit()
    db.refresh(doc)
    return doc

@router.get("/{file_no}/uploaded")
async def list_uploaded_documents(
    file_no: str,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """List uploaded documents for a file"""
    docs = db.query(Document).filter(Document.file_no == file_no).all()
    return docs

@router.delete("/uploaded/{doc_id}")
async def delete_document(
    doc_id: int,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Delete an uploaded document"""
    doc = db.query(Document).filter(Document.id == doc_id).first()
    if not doc:
        raise HTTPException(status_code=404, detail="Document not found")

    if os.path.exists(doc.path):
        os.remove(doc.path)

    db.delete(doc)
    db.commit()
    return {"message": "Document deleted successfully"}

@router.put("/uploaded/{doc_id}")
async def update_document(
    doc_id: int,
    description: str = Form(...),
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user)
):
    """Update document description"""
    doc = db.query(Document).filter(Document.id == doc_id).first()
    if not doc:
        raise HTTPException(status_code=404, detail="Document not found")

    doc.description = description
    db.commit()
    db.refresh(doc)
    return doc