import * as vscode from 'vscode';
import * as https from 'https';
import * as http from 'http';
import { URL } from 'url';

export interface HAEntity {
    entity_id: string;
    state: string;
    attributes: Record<string, unknown>;
    last_changed: string;
    last_updated: string;
}

/** Ensure URL has http(s):// prefix and no trailing slash */
function normalizeUrl(raw: string): string {
    let url = raw.trim().replace(/\/+$/, '');
    if (!/^https?:\/\//i.test(url)) {
        url = 'http://' + url;
    }
    return url;
}

export class HAClient {
    private entities: HAEntity[] = [];
    private entityMap: Map<string, HAEntity> = new Map();
    private refreshTimer: ReturnType<typeof setInterval> | undefined;
    private _onEntitiesUpdated = new vscode.EventEmitter<HAEntity[]>();
    readonly onEntitiesUpdated = this._onEntitiesUpdated.event;
    private log: vscode.OutputChannel;

    constructor(log: vscode.OutputChannel) {
        this.log = log;
        this.startAutoRefresh();
    }

    private getConfig() {
        const config = vscode.workspace.getConfiguration('appdaemon');
        return {
            url: normalizeUrl(config.get<string>('haUrl', 'http://localhost:8123')),
            token: config.get<string>('haToken', ''),
            refreshInterval: config.get<number>('entityRefreshInterval', 300)
        };
    }

    private async request<T = unknown>(method: string, path: string, body?: unknown): Promise<T> {
        const { url, token } = this.getConfig();
        if (!token) {
            throw new Error('HA token not configured — set appdaemon.haToken in settings');
        }

        const fullUrl = new URL(path, url);
        const isHttps = fullUrl.protocol === 'https:';
        const lib = isHttps ? https : http;

        this.log.appendLine(`[HA] ${method} ${fullUrl.href}`);

        return new Promise<T>((resolve, reject) => {
            const options: http.RequestOptions = {
                hostname: fullUrl.hostname,
                port: parseInt(fullUrl.port, 10) || (isHttps ? 443 : 8123),
                path: fullUrl.pathname + fullUrl.search,
                method,
                headers: {
                    'Authorization': `Bearer ${token}`,
                    'Content-Type': 'application/json'
                }
            };

            const req = lib.request(options, (res) => {
                let data = '';
                res.on('data', (chunk: Buffer) => { data += chunk; });
                res.on('end', () => {
                    this.log.appendLine(`[HA] ${res.statusCode} (${data.length} bytes)`);
                    if (res.statusCode && res.statusCode >= 200 && res.statusCode < 300) {
                        try {
                            resolve(JSON.parse(data) as T);
                        } catch {
                            resolve(data as unknown as T);
                        }
                    } else {
                        reject(new Error(`HTTP ${res.statusCode}: ${data.slice(0, 200)}`));
                    }
                });
            });

            req.on('error', (err) => {
                this.log.appendLine(`[HA] ERROR: ${err.message}`);
                reject(err);
            });
            req.setTimeout(15000, () => {
                req.destroy();
                reject(new Error('Request timed out'));
            });

            if (body) {
                req.write(JSON.stringify(body));
            }
            req.end();
        });
    }

    async fetchEntities(): Promise<HAEntity[]> {
        try {
            this.entities = await this.request<HAEntity[]>('GET', '/api/states');
            this.entityMap.clear();
            for (const entity of this.entities) {
                this.entityMap.set(entity.entity_id, entity);
            }
            this.log.appendLine(`[HA] Loaded ${this.entities.length} entities (${this.getDomains().length} domains)`);
            this._onEntitiesUpdated.fire(this.entities);
            return this.entities;
        } catch (e: unknown) {
            const msg = e instanceof Error ? e.message : String(e);
            this.log.appendLine(`[HA] fetchEntities FAILED: ${msg}`);
            vscode.window.showWarningMessage(`AppDaemon: Failed to fetch entities — ${msg}`);
            return this.entities;
        }
    }

    getEntities(): HAEntity[] {
        return this.entities;
    }

    getEntity(entityId: string): HAEntity | undefined {
        return this.entityMap.get(entityId);
    }

    getDomains(): string[] {
        const domains = new Set<string>();
        for (const entity of this.entities) {
            const dot = entity.entity_id.indexOf('.');
            if (dot > 0) {
                domains.add(entity.entity_id.substring(0, dot));
            }
        }
        return Array.from(domains).sort();
    }

    async restartHA(): Promise<void> {
        await this.request('POST', '/api/services/homeassistant/restart');
    }

    async restartHost(): Promise<void> {
        await this.request('POST', '/api/services/homeassistant/restart_host');
    }

    private startAutoRefresh() {
        const { refreshInterval } = this.getConfig();
        if (refreshInterval > 0) {
            this.refreshTimer = setInterval(() => {
                this.fetchEntities();
            }, refreshInterval * 1000);
        }
    }

    dispose() {
        if (this.refreshTimer) {
            clearInterval(this.refreshTimer);
        }
        this._onEntitiesUpdated.dispose();
    }
}