daily-report-bot/
  package.json
  src/
    index.js          # Main entry point
    commits.js        # Will collect git commits
    summarise.js      # Will call OpenAI
    slack.js          # Will post to Slack
    bank.js           # Will handle commit banking
  .env.example        # Template for environment variables

// src/commits.js
const { execSync } = require('child_process');

function getRecentCommits(hours = 24) {
  const since = new Date(Date.now() - hours * 60 * 60 * 1000).toISOString();

  try {
    const output = execSync(
      `git log --since="${since}" --pretty=format:"%H<SEP>%s<SEP>%an<SEP>%aI" --no-merges`,
      { encoding: 'utf-8' }
    );

    if (!output.trim()) {
      return [];
    }

    return output.trim().split('\n').map(line => {
      const [hash, message, author, date] = line.split('<SEP>');
      return { hash, message, author, date };
    });
  } catch (error) {
    console.error('Failed to read git log:', error.message);
    return [];
  }
}

module.exports = { getRecentCommits };

// src/bank.js
const fs = require('fs');
const path = require('path');

const STATE_FILE = path.join(__dirname, '..', 'state.json');

function loadState() {
  try {
    return JSON.parse(fs.readFileSync(STATE_FILE, 'utf-8'));
  } catch {
    return { bankedCommits: [] };
  }
}

function saveState(state) {
  fs.writeFileSync(STATE_FILE, JSON.stringify(state, null, 2));
}

function getRemainingWeekdays() {
  const today = new Date().getDay(); // 0=Sun, 1=Mon, ..., 5=Fri
  if (today === 0 || today === 6) return 0;
  return 6 - today; // days remaining including today: Mon=5, Tue=4, ..., Fri=1
}

function getTodaysBatch(newCommits) {
  const state = loadState();
  state.bankedCommits.push(...newCommits);

  const remaining = getRemainingWeekdays();
  if (remaining <= 0) return [];

  const isFriday = new Date().getDay() === 5;
  const batchSize = isFriday
    ? state.bankedCommits.length
    : Math.ceil(state.bankedCommits.length / remaining);

  const batch = state.bankedCommits.splice(0, batchSize);
  saveState(state);

  return batch;
}

module.exports = { getTodaysBatch, loadState, saveState };

// src/summarise.js
const OpenAI = require('openai');

const client = new OpenAI({ apiKey: process.env.OPENAI_API_KEY });

const SYSTEM_PROMPT = `You are a helpful assistant that writes daily standup updates.
Given a list of git commits, write a concise daily update in first person.
Group related work together. Use 3-5 bullet points.
Keep the tone warm and professional.
End with "Blockers: None" unless the commits suggest otherwise.
Do not include commit hashes or timestamps.`;

async function summariseCommits(commits) {
  if (commits.length === 0) {
    return "No updates today — no recent commits to report.";
  }

  const commitList = commits
    .map(c => `- ${c.message} (${c.date})`)
    .join('\n');

  const response = await client.chat.completions.create({
    model: 'gpt-4o-mini',
    messages: [
      { role: 'system', content: SYSTEM_PROMPT },
      { role: 'user', content: `Here are my recent commits:\n\n${commitList}\n\nWrite my daily standup update.` }
    ],
    temperature: 0.7,
    max_tokens: 500,
  });

  return response.choices[0].message.content;
}

module.exports = { summariseCommits };

// src/slack.js
async function postToSlack(summary) {
  const webhookUrl = process.env.SLACK_WEBHOOK_URL;

  if (!webhookUrl) {
    throw new Error('SLACK_WEBHOOK_URL environment variable is not set');
  }

  const today = new Date().toLocaleDateString('en-NZ', {
    weekday: 'long',
    year: 'numeric',
    month: 'long',
    day: 'numeric',
  });

  const payload = {
    blocks: [
      {
        type: 'header',
        text: { type: 'plain_text', text: `Daily Update — ${today}` },
      },
      {
        type: 'section',
        text: { type: 'mrkdwn', text: summary },
      },
    ],
  };

  const response = await fetch(webhookUrl, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(payload),
  });

  if (!response.ok) {
    const body = await response.text();
    throw new Error(`Slack webhook failed (${response.status}): ${body}`);
  }

  console.log('Posted to Slack successfully.');
}

module.exports = { postToSlack };

// src/index.js
const { getRecentCommits } = require('./commits');
const { getTodaysBatch } = require('./bank');
const { summariseCommits } = require('./summarise');
const { postToSlack } = require('./slack');

async function main() {
  const isDryRun = process.argv.includes('--dry-run') || process.env.DRY_RUN === 'true';
  const channel = process.argv.includes('--channel')
    ? process.argv[process.argv.indexOf('--channel') + 1]
    : process.env.SLACK_CHANNEL || 'test';

  // Set the right webhook URL based on channel
  if (channel === 'prod') {
    process.env.SLACK_WEBHOOK_URL = process.env.SLACK_WEBHOOK_PROD;
  } else {
    process.env.SLACK_WEBHOOK_URL = process.env.SLACK_WEBHOOK_TEST;
  }

  console.log(`Running daily report (dry-run: ${isDryRun}, channel: ${channel})`);

  // Step 1: Collect commits
  console.log('Collecting recent commits...');
  const commits = getRecentCommits();
  console.log(`Found ${commits.length} new commit(s).`);

  // Step 2: Bank and batch
  console.log('Processing commit bank...');
  const batch = getTodaysBatch(commits);
  console.log(`Today's batch: ${batch.length} commit(s).`);

  if (batch.length === 0) {
    console.log('No commits to report today. Exiting.');
    return;
  }

  // Step 3: Summarise
  console.log('Generating summary with OpenAI...');
  const summary = await summariseCommits(batch);
  console.log('\n--- Daily Report ---');
  console.log(summary);
  console.log('-------------------\n');

  // Step 4: Post to Slack
  if (isDryRun) {
    console.log('Dry run — skipping Slack post.');
  } else {
    console.log('Posting to Slack...');
    await postToSlack(summary);
  }

  console.log('Done!');
}

main().catch(error => {
  console.error('Error:', error.message);
  process.exit(1);
});