const { nanoid } = require('nanoid');
const inferenceClient = require('./inferenceClient');
const toolManager = require('./toolManager');
const sandbox = require('./sandbox');
const errorHealer = require('./errorHealer');

const AGENT_NAME = process.env.AGENT_NAME || 'Forge';
const MAX_TOOL_ITERATIONS = 20;

const path = require('path');
const fs = require('fs');
const projectRoot = path.resolve(__dirname, '..');

function systemPrompt() {
  return `${AGENT_NAME}. Project files: public/index.html, public/styles.css, public/app.js, src/*.js, server.js. To edit: <write path>content</write>. To read: <read path>. Tactical and concise.`;
}

function makeLogEntry(type, fields = {}) {
  return { id: nanoid(10), type, ts: new Date().toISOString(), ...fields };
}

const VALID_DIRS = ['src/', 'public/', 'scripts/', ''];
const EXTENSIONS = ['.js', '.css', '.html', '.json', '.yml', '.yaml', '.sh', '.md'];

function findFileName(line) {
  const parts = line.trim().split(/[ `'"]+/);
  const candidate = parts[parts.length - 1].replace(/[`'"]/g, '').trim();
  if (!candidate || candidate === '') return null;
  const abs = path.resolve(projectRoot, candidate);
  if (abs.startsWith(projectRoot) && (
    candidate.includes('.') ||
    VALID_DIRS.some(d => candidate.startsWith(d))
  )) return candidate;
  return null;
}

function processFileActions(content) {
  const actions = [];
  let text = content;

  const readRe = /<read\s+([^>]+)>/g;
  let m;
  while ((m = readRe.exec(content)) !== null) {
    const filePath = m[1].trim();
    const absPath = path.resolve(projectRoot, filePath);
    if (filePath.includes('..') || !absPath.startsWith(projectRoot)) continue;
    try {
      actions.push({ type: 'read', path: filePath, result: fs.readFileSync(absPath, 'utf8') });
    } catch { actions.push({ type: 'ignored', message: `could not read ${filePath}` }); }
  }
  text = text.replace(readRe, '');

  const writeRe = /<write\s+([^>]+)>([\s\S]*?)<\/write>/g;
  while ((m = writeRe.exec(content)) !== null) {
    const filePath = m[1].trim();
    const fileContent = m[2];
    const absPath = path.resolve(projectRoot, filePath);
    if (filePath.includes('..') || !absPath.startsWith(projectRoot)) continue;
    try {
      fs.mkdirSync(path.dirname(absPath), { recursive: true });
      fs.writeFileSync(absPath, fileContent, 'utf8');
      actions.push({ type: 'write', path: filePath });
    } catch (err) { actions.push({ type: 'ignored', message: `could not write ${filePath}: ${err.message}` }); }
  }
  text = text.replace(writeRe, '');

  // Handle <css> as write to public/styles.css
  const cssRe = /<css>([\s\S]*?)<\/css>/g;
  while ((m = cssRe.exec(content)) !== null) {
    const cssContent = m[1];
    const absPath = path.resolve(projectRoot, 'public/styles.css');
    try {
      const existing = fs.readFileSync(absPath, 'utf8');
      fs.writeFileSync(absPath, existing + '\n' + cssContent, 'utf8');
    } catch {
      fs.writeFileSync(absPath, cssContent, 'utf8');
    }
    actions.push({ type: 'write', path: 'public/styles.css (appended)' });
  }
  text = text.replace(cssRe, '');

  // Handle <javascript> as write to public/app.js
  const jsRe = /<javascript>([\s\S]*?)<\/javascript>/g;
  while ((m = jsRe.exec(content)) !== null) {
    const jsContent = m[1];
    const absPath = path.resolve(projectRoot, 'public/app.js');
    try {
      const existing = fs.readFileSync(absPath, 'utf8');
      fs.writeFileSync(absPath, existing + '\n' + jsContent, 'utf8');
    } catch {
      fs.writeFileSync(absPath, jsContent, 'utf8');
    }
    actions.push({ type: 'write', path: 'public/app.js (appended)' });
  }
  text = text.replace(jsRe, '').trim();

  return { cleanText: text, actions };
}

function createAgent(io) {
  const llmHistory = [];
  const displayLog = [];

  function pushLog(entry) {
    displayLog.push(entry);
    io.emit('log:entry', entry);
    return entry;
  }

  function setStatus(state, detail) {
    io.emit('agent:status', { state, detail: detail || null });
  }

  async function runLoop() {
    try {
      for (let i = 0; i < MAX_TOOL_ITERATIONS; i++) {
        setStatus('thinking');
        const apiMessages = [{ role: 'system', content: systemPrompt() }, ...llmHistory];

        let message;
        try {
          message = await inferenceClient.chat(apiMessages);
        } catch (err) {
          setStatus('idle');
          pushLog(makeLogEntry('assistant', { content: `I couldn't reach the Inference Port API: ${err.message}` }));
          return;
        }

        const rawContent = message.content || '';

        const { cleanText, actions } = processFileActions(rawContent);

        if (actions.length > 0) {
          for (const action of actions) {
            if (action.type === 'read') {
              llmHistory.push({ role: 'system', content: `Contents of \`${action.path}\`:\n\`\`\`\n${action.result}\n\`\`\`` });
            } else if (action.type === 'write') {
              llmHistory.push({ role: 'system', content: `Written \`${action.path}\`` });
            } else if (action.type === 'error') {
              llmHistory.push({ role: 'system', content: `Error on \`${action.path}\`: ${action.message}` });
            }
          }
          continue;
        }

        setStatus('idle');
        const displayContent = rawContent || '...';
        pushLog(makeLogEntry('assistant', { content: displayContent }));
        return;
      }
    } catch (err) {
      setStatus('idle');
      pushLog(makeLogEntry('assistant', { content: `Something went wrong: ${err.message}` }));
      return;
    }
    setStatus('idle');
    pushLog(makeLogEntry('assistant', { content: "I've gone through a few iterations without wrapping up - pausing here. What would you like next?" }));
  }

  const MAX_HISTORY = 20;

  function trimHistory() {
    while (llmHistory.length > MAX_HISTORY) {
      llmHistory.shift();
    }
  }

  async function handleUserMessage(text) {
    const trimmed = String(text || '').trim();
    if (!trimmed) return;
    trimHistory();
    llmHistory.push({ role: 'user', content: trimmed });

    const wantsEdit = /edit|change|add|update|toggle|mode|feature/i.test(trimmed);
    if (wantsEdit) {
      const files = ['public/index.html', 'public/styles.css', 'public/app.js'];
      const contents = files.map(f => {
        try {
          return `public/${f}:\n\`\`\`\n${fs.readFileSync(path.join(projectRoot, 'public', f), 'utf8')}\n\`\`\``;
        } catch { return null; }
      }).filter(Boolean).join('\n\n');
      llmHistory.push({
        role: 'system',
        content: `Here are the current file contents:\n\n${contents}\n\nTo make changes, use EXACTLY: <write path>content</write>`
      });
    }

    pushLog(makeLogEntry('user', { content: trimmed }));
    await runLoop();
  }

  async function handleApprove(toolId) {
    const tool = toolManager.approveTool(toolId);
    pushLog(makeLogEntry('tool_update', { tool, action: 'approved', matchId: toolId }));
    llmHistory.push({
      role: 'system',
      content: `The user approved the tool "${tool.name}" (id: ${tool.id}). It is now available to call. Continue what you were doing if it's still relevant.`,
    });
    await runLoop();
  }

  async function handleReject(toolId, reason) {
    const tool = toolManager.rejectTool(toolId, reason);
    pushLog(makeLogEntry('tool_update', { tool, action: 'rejected', reason, matchId: toolId }));
    llmHistory.push({
      role: 'system',
      content: `The user rejected the tool "${tool.name}" (id: ${tool.id}).${reason ? ` Reason: ${reason}` : ''} Do not propose the same thing again unchanged - either adjust your approach or ask the user what they'd prefer.`,
    });
    await runLoop();
  }

  function setModel(name) {
    inferenceClient.setModel(name);
    io.emit('model:changed', { model: inferenceClient.getModel() });
  }

  function snapshot() {
    return {
      log: displayLog,
      tools: toolManager.listTools(),
      model: inferenceClient.getModel(),
      availableModels: inferenceClient.AVAILABLE_MODELS,
    };
  }

  return { handleUserMessage, handleApprove, handleReject, snapshot, setModel };
}

module.exports = { createAgent, AGENT_NAME };