from __future__ import annotations

import uuid
from datetime import datetime, timezone

from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.db.models.category import Category

SYSTEM_CATEGORIES = [
    # Income
    {"name": "Salary", "type": "income", "icon": "briefcase", "color": "#22c55e"},
    {"name": "Freelance", "type": "income", "icon": "laptop", "color": "#22c55e"},
    {"name": "Investment Income", "type": "income", "icon": "trending-up", "color": "#22c55e"},
    {"name": "Rental Income", "type": "income", "icon": "home", "color": "#22c55e"},
    {"name": "Benefits", "type": "income", "icon": "shield", "color": "#22c55e"},
    {"name": "Other Income", "type": "income", "icon": "plus-circle", "color": "#22c55e"},
    # Expenses — Housing
    {"name": "Rent / Mortgage", "type": "expense", "icon": "home", "color": "#6366f1"},
    {"name": "Council Tax", "type": "expense", "icon": "landmark", "color": "#6366f1"},
    {"name": "Home Insurance", "type": "expense", "icon": "shield", "color": "#6366f1"},
    {"name": "Home Maintenance", "type": "expense", "icon": "wrench", "color": "#6366f1"},
    # Utilities
    {"name": "Electricity", "type": "expense", "icon": "zap", "color": "#f59e0b"},
    {"name": "Gas", "type": "expense", "icon": "flame", "color": "#f59e0b"},
    {"name": "Water", "type": "expense", "icon": "droplets", "color": "#f59e0b"},
    {"name": "Internet", "type": "expense", "icon": "wifi", "color": "#f59e0b"},
    {"name": "Phone", "type": "expense", "icon": "smartphone", "color": "#f59e0b"},
    # Food
    {"name": "Groceries", "type": "expense", "icon": "shopping-cart", "color": "#ec4899"},
    {"name": "Eating Out", "type": "expense", "icon": "utensils", "color": "#ec4899"},
    {"name": "Coffee", "type": "expense", "icon": "coffee", "color": "#ec4899"},
    {"name": "Takeaway", "type": "expense", "icon": "package", "color": "#ec4899"},
    # Transport
    {"name": "Fuel", "type": "expense", "icon": "fuel", "color": "#0ea5e9"},
    {"name": "Public Transport", "type": "expense", "icon": "bus", "color": "#0ea5e9"},
    {"name": "Car Insurance", "type": "expense", "icon": "car", "color": "#0ea5e9"},
    {"name": "Car Maintenance", "type": "expense", "icon": "wrench", "color": "#0ea5e9"},
    {"name": "Parking", "type": "expense", "icon": "parking-circle", "color": "#0ea5e9"},
    {"name": "Taxi / Ride share", "type": "expense", "icon": "map-pin", "color": "#0ea5e9"},
    # Health
    {"name": "Healthcare", "type": "expense", "icon": "heart-pulse", "color": "#ef4444"},
    {"name": "Pharmacy", "type": "expense", "icon": "pill", "color": "#ef4444"},
    {"name": "Gym", "type": "expense", "icon": "dumbbell", "color": "#ef4444"},
    # Personal
    {"name": "Clothing", "type": "expense", "icon": "shirt", "color": "#a855f7"},
    {"name": "Personal Care", "type": "expense", "icon": "sparkles", "color": "#a855f7"},
    {"name": "Subscriptions", "type": "expense", "icon": "repeat", "color": "#a855f7"},
    {"name": "Entertainment", "type": "expense", "icon": "tv", "color": "#a855f7"},
    {"name": "Holidays", "type": "expense", "icon": "plane", "color": "#a855f7"},
    # Finance
    {"name": "Loan Repayment", "type": "expense", "icon": "credit-card", "color": "#64748b"},
    {"name": "Mortgage Payment", "type": "expense", "icon": "building", "color": "#64748b"},
    {"name": "Bank Charges", "type": "expense", "icon": "landmark", "color": "#64748b"},
    {"name": "Interest Paid", "type": "expense", "icon": "percent", "color": "#64748b"},
    # Savings
    {"name": "Savings", "type": "expense", "icon": "piggy-bank", "color": "#10b981"},
    {"name": "Investments", "type": "expense", "icon": "trending-up", "color": "#10b981"},
    # Other
    {"name": "Gifts", "type": "expense", "icon": "gift", "color": "#f97316"},
    {"name": "Education", "type": "expense", "icon": "graduation-cap", "color": "#f97316"},
    {"name": "Other Expense", "type": "expense", "icon": "more-horizontal", "color": "#64748b"},
    # Transfers
    {"name": "Transfer", "type": "transfer", "icon": "arrow-left-right", "color": "#94a3b8"},
]


async def seed_system_categories(db: AsyncSession) -> None:
    existing = await db.scalar(
        select(Category).where(Category.is_system == True).limit(1)
    )
    if existing:
        return

    now = datetime.now(timezone.utc)
    for i, cat in enumerate(SYSTEM_CATEGORIES):
        db.add(Category(
            user_id=None,
            name=cat["name"],
            type=cat["type"],
            icon=cat.get("icon"),
            color=cat.get("color"),
            is_system=True,
            sort_order=i,
            created_at=now,
        ))
    await db.flush()


async def list_categories(db: AsyncSession, user_id: uuid.UUID) -> list[dict]:
    result = await db.execute(
        select(Category).where(
            (Category.user_id == user_id) | (Category.user_id.is_(None))
        ).order_by(Category.type, Category.sort_order, Category.name)
    )
    cats = result.scalars().all()
    return [
        {
            "id": str(c.id),
            "name": c.name,
            "type": c.type,
            "icon": c.icon,
            "color": c.color,
            "is_system": c.is_system,
            "parent_id": str(c.parent_id) if c.parent_id else None,
            "sort_order": c.sort_order,
        }
        for c in cats
    ]


async def create_category(
    db: AsyncSession,
    user_id: uuid.UUID,
    name: str,
    type_: str,
    icon: str | None = None,
    color: str | None = None,
    parent_id: uuid.UUID | None = None,
) -> dict:
    now = datetime.now(timezone.utc)
    cat = Category(
        user_id=user_id,
        name=name,
        type=type_,
        icon=icon,
        color=color,
        parent_id=parent_id,
        is_system=False,
        created_at=now,
    )
    db.add(cat)
    await db.flush()
    return {"id": str(cat.id), "name": cat.name, "type": cat.type, "icon": cat.icon, "color": cat.color, "is_system": False}