import { Injectable, NotFoundException, BadRequestException } from '@nestjs/common';
import { PlantationNodeData, Worker, Task } from './plantation-node-data.interface';
import { TreeNode, TreeService } from 'src/services/tree.service';

@Injectable()
export class PlantationTreeService extends TreeService<PlantationNodeData> {
    private workerIndex: Map<string, Worker> = new Map();
    // plantation-tree.service.ts (constructor only)
    constructor() {
        super({
            id: 'root',
            data: {
                id: 'root',
                name: 'Plantation Root',
                type: 'ROOT',     // <-- ensure ROOT here
                status: 'ACTIVE',
                workers: [],
            },
        });
    }

    /** 🔍 Find a node by name (case-insensitive) */
    findNodeByName(name: string): TreeNode<PlantationNodeData> | undefined {
        let found: TreeNode<PlantationNodeData> | undefined;
        this.traverseTree(node => {
            if (node.data.name.toLowerCase() === name.toLowerCase()) found = node;
        });
        return found;
    }

    /** 👷 Assign worker to ZONE or BLOCK (not TREE), propagates upward */
    assignWorker(nodeId: string, worker: Worker): TreeNode<PlantationNodeData> {
        // 1️⃣ Check uniqueness globally
        if (this.workerIndex.has(worker.id)) {
            throw new BadRequestException(`Worker ID ${worker.id} already exists`);
        }

        const node = this.root.first(n => n.model.id === nodeId);
        if (!node) throw new NotFoundException(`Node ${nodeId} not found`);

        if (!node.model.data.workers) node.model.data.workers = [];
        node.model.data.workers.push(worker);

        // 2️⃣ Propagate upward to ancestors
        let current = node.parent;
        while (current) {
            if (!current.model.data.workers) current.model.data.workers = [];
            const parentHasWorker = current.model.data.workers.some(w => w.id === worker.id);
            if (!parentHasWorker) current.model.data.workers.push(worker);
            current = current.parent;
        }

        // 3️⃣ Update global index
        this.workerIndex.set(worker.id, worker);

        return node.model;
    }

    /** 🌳 Assign tree to an existing worker (must exist in ancestor chain) */
    assignTreeToWorker(treeId: string, workerId: string): TreeNode<PlantationNodeData> {
        const treeNode = this.root.first(n => n.model.id === treeId);
        if (!treeNode) throw new NotFoundException(`Tree node ${treeId} not found`);

        if (treeNode.model.data.type !== 'TREE') {
            throw new BadRequestException(`Only TREE nodes can be assigned to workers`);
        }

        // Search upward for worker existence
        let current = treeNode.parent;
        let foundWorker: Worker | null = null;
        while (current) {
            const worker = current.model.data.workers?.find(w => w.id === workerId);
            if (worker) {
                foundWorker = worker;
                break;
            }
            current = current.parent;
        }

        if (!foundWorker) {
            throw new NotFoundException(`Worker ${workerId} not found in ancestor hierarchy`);
        }

        // Assign minimal worker data to tree node
        treeNode.model.data.workers = [
            {
                id: foundWorker.id,
                name: foundWorker.name,
                personCode: foundWorker.personCode,
                role: foundWorker.role,
                DOB: foundWorker.DOB,
                age: foundWorker.age,
                nationality: foundWorker.nationality,
            },
        ];

        return treeNode.model;
    }

    /** 📋 Assign a task to a worker under a node */
    assignTaskToWorkerById(workerId: string, task: Task): Worker {
        const worker = this.workerIndex.get(workerId);
        if (!worker) throw new NotFoundException(`Worker ${workerId} not found`);

        if (!worker.assignedTasks) worker.assignedTasks = [];
        worker.assignedTasks.push(task);

        return worker;
    }

    /** 🌲 Recursively collect all workers under a node (aggregated view) */
    getWorkersUnderNode(nodeId: string): Worker[] {
        const start = this.root.first(n => n.model.id === nodeId);
        if (!start) throw new NotFoundException(`Node ${nodeId} not found`);

        const workers: Worker[] = [];
        start.walk(n => {
            if (n.model.data.workers) workers.push(...n.model.data.workers);
            return true;
        });
        return workers;
    }

    /** ✅ Update node metadata safely */
    updateMetadata(nodeId: string, metadata: Record<string, any>) {
        const node = this.root.first(n => n.model.id === nodeId);
        if (!node) throw new NotFoundException(`Node ${nodeId} not found`);
        node.model.data.metadata = { ...node.model.data.metadata, ...metadata };
        return node.model;
    }

    getWorkerById(workerId: string): Worker {
        const worker = this.workerIndex.get(workerId);
        if (!worker) throw new NotFoundException(`Worker ${workerId} not found`);
        return worker;
    }
}