from typing import Optional
from fastapi import APIRouter, Depends, Query
from sqlalchemy.orm import Session
from sqlalchemy import func

from app.core.database import get_db
from app.models.user import User
from app.models.metadata import DataSource, DataTable, DataColumn
from app.models.project import ClassificationResult, ClassificationProject
from app.models.classification import Category, DataLevel
from app.schemas.common import ResponseModel
from app.api.deps import get_current_user

router = APIRouter()


@router.get("/stats")
def get_dashboard_stats(
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """Dashboard overview statistics based on real DB data."""
    data_sources = db.query(DataSource).count()
    tables = db.query(DataTable).count()
    columns = db.query(DataColumn).count()
    labeled = db.query(ClassificationResult).count()
    sensitive = db.query(ClassificationResult).join(DataLevel).filter(
        DataLevel.code.in_(['L4', 'L5'])
    ).count()
    projects = db.query(ClassificationProject).count()

    return ResponseModel(data={
        "data_sources": data_sources,
        "tables": tables,
        "columns": columns,
        "labeled": labeled,
        "sensitive": sensitive,
        "projects": projects,
    })


@router.get("/distribution")
def get_dashboard_distribution(
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """Distribution data for charts based on real DB data."""
    # Level distribution
    level_dist = db.query(DataLevel.name, DataLevel.code, DataLevel.color, func.count(ClassificationResult.id)).\
        join(ClassificationResult, DataLevel.id == ClassificationResult.level_id).\
        group_by(DataLevel.id).\
        order_by(DataLevel.sort_order).all()

    # Category distribution
    category_dist = db.query(Category.name, func.count(ClassificationResult.id)).\
        join(ClassificationResult, Category.id == ClassificationResult.category_id).\
        group_by(Category.id).\
        order_by(func.count(ClassificationResult.id).desc()).limit(8).all()

    # Source distribution
    source_dist = db.query(ClassificationResult.source, func.count(ClassificationResult.id)).\
        group_by(ClassificationResult.source).all()

    # Project progress
    projects = db.query(ClassificationProject).all()
    project_progress = []
    for p in projects:
        total = db.query(ClassificationResult).filter(ClassificationResult.project_id == p.id).count()
        reviewed = db.query(ClassificationResult).filter(
            ClassificationResult.project_id == p.id,
            ClassificationResult.status == 'reviewed',
        ).count()
        project_progress.append({
            "id": p.id,
            "name": p.name,
            "status": p.status,
            "progress": round(reviewed / total * 100) if total else 0,
            "planned_end": p.planned_end.isoformat() if p.planned_end else None,
        })

    # Heatmap: source vs level
    sources = db.query(DataSource).order_by(DataSource.id).limit(8).all()
    levels = db.query(DataLevel).order_by(DataLevel.sort_order).all()
    heatmap = []
    for si, source in enumerate(sources):
        for li, level in enumerate(levels):
            count = db.query(func.count(ClassificationResult.id)).\
                join(DataColumn, ClassificationResult.column_id == DataColumn.id).\
                join(DataTable, DataColumn.table_id == DataTable.id).\
                join(DataSource, DataTable.database_id == DataSource.id).\
                filter(DataSource.id == source.id, ClassificationResult.level_id == level.id).scalar()
            heatmap.append({
                "source_name": source.name,
                "level_code": level.code,
                "count": count or 0,
            })

    return ResponseModel(data={
        "level_distribution": [
            {"name": name, "code": code, "color": color, "count": count}
            for name, code, color, count in level_dist
        ],
        "category_distribution": [
            {"name": name, "count": count}
            for name, count in category_dist
        ],
        "source_distribution": [
            {"source": src, "count": count}
            for src, count in source_dist
        ],
        "project_progress": project_progress,
        "heatmap": heatmap,
    })