import { preprocess, preprocessString, toLlmContext } from "langmail";
import { readFileSync } from "fs";

// From a raw .eml file
const raw = readFileSync("message.eml");
const email = preprocess(raw);

// Or from a string (e.g. Gmail API response)
const fromString = preprocessString(rawEmailString);

console.log(email.body);
// → "Hi Alice! Great to hear from you."

console.log(email.from);
// → { name: "Bob", email: "bob@example.com" }

// Format for an LLM prompt
console.log(toLlmContext(email));
// FROM: Bob <bob@example.com>
// TO: Alice <alice@example.com>
// SUBJECT: Re: Project update
// DATE: 2024-01-15T10:30:00Z
// CONTENT:
// Hi Alice! Great to hear from you.

import { preprocess } from "langmail";
import { readFileSync } from "fs";

const raw = readFileSync("message.eml");
const email = preprocess(raw);

import { preprocessString } from "langmail";

const email = preprocessString(rawEmailString);

import { preprocessWithOptions } from "langmail";

const email = preprocessWithOptions(raw, {
  stripQuotes: true,      // Remove quoted replies (default: true)
  stripSignature: true,   // Remove email signatures (default: true)
  maxBodyLength: 4000,    // Truncate body to N chars (default: 0 = no limit)
});

import { preprocess, toLlmContext } from "langmail";

const email = preprocess(raw);
console.log(toLlmContext(email));
// FROM: Bob <bob@example.com>
// TO: Alice <alice@example.com>
// SUBJECT: Re: Project update
// DATE: 2024-01-15T10:30:00Z
// CONTENT:
// Hi Alice! Great to hear from you.

import { preprocess, toLlmContextWithOptions } from "langmail";

const email = preprocess(raw);

// Default: only the latest message
console.log(toLlmContextWithOptions(email, { renderMode: "LatestOnly" }));

// Include thread history
console.log(toLlmContextWithOptions(email, { renderMode: "ThreadHistory" }));
// FROM: Bob <bob@example.com>
// SUBJECT: Re: Project update
// CONTENT:
// Hi Alice! Great to hear from you.
//
// THREAD HISTORY (oldest first):
// ---
// FROM: Alice <alice@example.com>
// DATE: 2024-01-14T09:00:00Z
// Alice's original message here...
// ---

interface ProcessedEmail {
  body: string;                    // Clean Markdown, ready for your LLM
  subject?: string;
  from?: Address;
  to: Address[];
  cc: Address[];
  date?: string;                   // ISO 8601
  rfcMessageId?: string;           // RFC 2822 Message-ID header
  inReplyTo?: string[];            // In-Reply-To header (threading)
  references?: string[];           // References header (threading)
  signature?: string;              // Extracted signature, if found
  rawBodyLength: number;           // Body length before cleaning
  cleanBodyLength: number;         // Body length after cleaning
  primaryCta?: CallToAction;       // Primary call-to-action from HTML body
  threadMessages: ThreadMessage[]; // Quoted replies, oldest first
}

interface Address {
  name?: string;  // Display name (e.g. "Alice")
  email: string;  // Email address (e.g. "alice@example.com")
}

interface CallToAction {
  url: string;        // The URL the action points to
  text: string;       // Human-readable label
  confidence: number; // Score between 0.0 and 1.0
}

interface ThreadMessage {
  sender: string;     // Sender attribution (e.g. "Max <max@example.com>")
  timestamp?: string; // ISO 8601, if parseable from the attribution
  body: string;       // Message body (cleaned, no nested quotes)
}

interface PreprocessOptions {
  stripQuotes?: boolean;    // Remove quoted replies (default: true)
  stripSignature?: boolean; // Remove email signatures (default: true)
  maxBodyLength?: number;   // Max body chars, 0 = no limit (default: 0)
}

interface LlmContextOptions {
  renderMode?: RenderMode; // Default: "LatestOnly"
}

// TypeScript enum — JS users pass the string literals directly ("LatestOnly" or "ThreadHistory")
const enum RenderMode {
  /** Only the latest message — all quoted content stripped. */
  LatestOnly = "LatestOnly",
  /** Chronological transcript of quoted replies below the main content. */
  ThreadHistory = "ThreadHistory",
}