// Adds a custom AI menu to the Google Docs interface
function onOpen() {
  DocumentApp.getUi()
    .createMenu("AI Tools")
    .addItem("Format with GPT", "sendToGPT")
    .addItem("Format with Claude", "sendToClaude")
    .addToUi();
}

// Retrieves the OpenAI API key from script properties
function getApiKey() {
  const props = PropertiesService.getScriptProperties();
  return props.getProperty("OPENAI_API_KEY");
}

// Retrieves the Claude API key from script properties
function getClaudeApiKey() {
  const props = PropertiesService.getScriptProperties();
  return props.getProperty("CLAUDE_API_KEY");
}

// Sends selected text to GPT and inserts the response after the selection
function sendToGPT() {
  const doc = DocumentApp.getActiveDocument();
  const selection = doc.getSelection();

  if (!selection) {
    DocumentApp.getUi().alert("Please select some text in the document.");
    return;
  }

  let selectedText = "";
  const elements = selection.getRangeElements();
  for (const el of elements) {
    if (el.getElement().editAsText) {
      selectedText += el.getElement().asText().getText().substring(
        el.getStartOffset(),
        el.getEndOffsetInclusive() + 1
      );
    }
  }

  const instruction = DocumentApp.getUi().prompt("Enter your instruction for GPT (e.g. summarise, rewrite):").getResponseText();
  if (!instruction) return;

  const prompt = `${instruction}:\n\n${selectedText}`;
  const response = callGPTAPI(prompt);

  if (response) {
    for (const el of elements.reverse()) {
      if (el.getElement().editAsText) {
        const text = el.getElement().asText();
        const end = el.getEndOffsetInclusive();
        text.insertText(end + 1, "\n---\nGPT response:\n" + response);
        break;
      }
    }
  }
}

// Sends selected text to Claude and inserts the response after the selection
function sendToClaude() {
  const doc = DocumentApp.getActiveDocument();
  const selection = doc.getSelection();

  if (!selection) {
    DocumentApp.getUi().alert("Please select some text in the document.");
    return;
  }

  let selectedText = "";
  const elements = selection.getRangeElements();
  for (const el of elements) {
    if (el.getElement().editAsText) {
      selectedText += el.getElement().asText().getText().substring(
        el.getStartOffset(),
        el.getEndOffsetInclusive() + 1
      );
    }
  }

  const instruction = DocumentApp.getUi().prompt("Enter your instruction for Claude (e.g. simplify, edit, summarise):").getResponseText();
  if (!instruction) return;

  const prompt = `${instruction}:\n\n${selectedText}`;
  const response = callClaudeAPI(prompt);

  if (response) {
    for (const el of elements.reverse()) {
      if (el.getElement().editAsText) {
        const text = el.getElement().asText();
        const end = el.getEndOffsetInclusive();
        text.insertText(end + 1, "\n---\nClaude response:\n" + response);
        break;
      }
    }
  }
}

// Calls the OpenAI GPT API and returns the response
function callGPTAPI(prompt) {
  const url = "https://api.openai.com/v1/chat/completions";
  const payload = {
    model: "gpt-4",
    messages: [
      { role: "system", content: "You are a helpful scientific writing assistant." },
      { role: "user", content: prompt }
    ],
    temperature: 0.7
  };

  const options = {
    method: "post",
    contentType: "application/json",
    headers: {
      Authorization: `Bearer ${getApiKey()}`
    },
    payload: JSON.stringify(payload),
    muteHttpExceptions: true
  };

  try {
    const response = UrlFetchApp.fetch(url, options);
    const json = JSON.parse(response.getContentText());
    if (json.choices && json.choices.length > 0) {
      return json.choices[0].message.content.trim();
    } else {
      Logger.log(json);
      DocumentApp.getUi().alert("No response received from GPT.");
      return null;
    }
  } catch (e) {
    Logger.log(e);
    DocumentApp.getUi().alert("GPT API error: " + e);
    return null;
  }
}

// Calls the Claude API and returns the response
function callClaudeAPI(prompt) {
  const url = "https://api.anthropic.com/v1/messages";
  const payload = {
    model: "claude-3-opus-20240229",
    max_tokens: 1024,
    temperature: 0.7,
    messages: [
      {
        role: "user",
        content: prompt
      }
    ]
  };

  const options = {
    method: "post",
    contentType: "application/json",
    headers: {
      "x-api-key": getClaudeApiKey(),
      "anthropic-version": "2023-06-01"
    },
    payload: JSON.stringify(payload),
    muteHttpExceptions: true
  };

  try {
    const response = UrlFetchApp.fetch(url, options);
    const json = JSON.parse(response.getContentText());
    if (json.content && json.content.length > 0 && json.content[0].text) {
      return json.content[0].text.trim();
    } else {
      Logger.log(json);
      DocumentApp.getUi().alert("No response received from Claude.");
      return null;
    }
  } catch (e) {
    Logger.log(e);
    DocumentApp.getUi().alert("Claude API error: " + e);
    return null;
  }
}