// src/rules-engine/rules-engine.controller.ts

import { Controller, Get, Post, Put, Delete, Patch, Param, Body, HttpException, Logger } from '@nestjs/common';
import { RulesStorageService } from './rules-storage.service';
import { RulesEngineService } from './rules-engine.service';
import type { Rule, PriorityConfig } from './types/rule.types';
import { readFileSync } from 'fs';
import { join } from 'path';

@Controller('api/rules')
export class RulesEngineController {
    private readonly logger = new Logger(RulesEngineController.name);

    constructor(
        private readonly storage: RulesStorageService,
        private readonly engine: RulesEngineService,
    ) {}

    // --- Priority Config (slider UI) ---

    @Get('priority-config')
    async getPriorityConfig() {
        return this.storage.getPriorityConfig();
    }

    @Put('priority-config')
    async updatePriorityConfig(@Body() body: PriorityConfig) {
        return this.storage.updatePriorityConfig(body);
    }

    // --- Rule CRUD ---

    @Get()
    async listRules() {
        return this.storage.getAll();
    }

    @Get(':id')
    async getRule(@Param('id') id: string) {
        const rule = await this.storage.getById(id);
        if (!rule) throw new HttpException('Rule not found', 404);
        return rule;
    }

    @Post()
    async createRule(@Body() body: any) {
        if (!body.name || !body.trigger || !body.conditions || !body.action) {
            throw new HttpException('name, trigger, conditions, and action are required', 400);
        }
        return this.storage.create({
            ...body,
            ruleType: body.ruleType ?? 'priority',
            enabled: body.enabled ?? true,
            priority: body.priority ?? 99,
        });
    }

    @Put(':id')
    async updateRule(@Param('id') id: string, @Body() body: Partial<Rule>) {
        const updated = await this.storage.update(id, body);
        if (!updated) throw new HttpException('Rule not found', 404);
        return updated;
    }

    @Delete(':id')
    async deleteRule(@Param('id') id: string) {
        const deleted = await this.storage.delete(id);
        if (!deleted) throw new HttpException('Rule not found', 404);
        return { status: 'ok' };
    }

    @Patch(':id/toggle')
    async toggleRule(@Param('id') id: string) {
        const toggled = await this.storage.toggle(id);
        if (!toggled) throw new HttpException('Rule not found', 404);
        return toggled;
    }

    @Post('reorder')
    async reorderRules(@Body() body: { ids: string[] }) {
        if (!body.ids?.length) throw new HttpException('ids array required', 400);
        return this.storage.reorder(body.ids);
    }

    // --- Evaluation ---

    @Post('evaluate')
    async evaluate(@Body() body: { trigger: string; triggerValue: string; facts: Record<string, any> }) {
        return this.engine.evaluate(body.trigger, body.triggerValue, body.facts);
    }

    // --- Templates ---

    @Get('templates/list')
    async listTemplates() {
        return [{ id: 'hospital-starter', name: 'Hospital Starter Pack', description: 'Default rules for a hospital call center', ruleCount: 7 }];
    }

    @Post('templates/:id/apply')
    async applyTemplate(@Param('id') id: string) {
        if (id !== 'hospital-starter') throw new HttpException('Template not found', 404);

        let template: any;
        try {
            template = JSON.parse(readFileSync(join(__dirname, 'templates', 'hospital-starter.json'), 'utf8'));
        } catch {
            throw new HttpException('Failed to load template', 500);
        }

        // Apply priority config
        await this.storage.updatePriorityConfig(template.priorityConfig);

        // Create rules
        const created: Rule[] = [];
        for (const rule of template.rules) {
            const newRule = await this.storage.create(rule);
            created.push(newRule);
        }

        this.logger.log(`Applied hospital-starter template: ${created.length} rules + priority config`);
        return { status: 'ok', rulesCreated: created.length, rules: created };
    }
}