const fs = require('fs');
const path = require('path');
const { nanoid } = require('nanoid');

// Persist tools to /data (HF persistent storage) when USE_PERSISTENT_STORAGE
// is explicitly set. Defaults to the local tools/ directory to avoid hanging
// on a slow/broken network mount during startup.
function resolveBaseDir() {
  if (process.env.USE_PERSISTENT_STORAGE) {
    const candidate = '/data/forge-tools';
    try {
      fs.mkdirSync(candidate, { recursive: true });
      fs.accessSync(candidate, fs.constants.W_OK);
      return candidate;
    } catch {}
  }
  const fallback = path.join(__dirname, '..', 'tools');
  fs.mkdirSync(fallback, { recursive: true });
  return fallback;
}

const BASE_DIR = resolveBaseDir();
const MANIFEST_PATH = path.join(BASE_DIR, 'manifest.json');
const usingPersistentStorage = !!(process.env.USE_PERSISTENT_STORAGE && BASE_DIR.startsWith('/data'));

function loadManifest() {
  try {
    return JSON.parse(fs.readFileSync(MANIFEST_PATH, 'utf8'));
  } catch {
    return [];
  }
}

function saveManifest(tools) {
  fs.writeFileSync(MANIFEST_PATH, JSON.stringify(tools, null, 2));
}

let tools = loadManifest();

function persist() {
  saveManifest(tools);
}

function listTools(status) {
  return status ? tools.filter((t) => t.status === status) : tools;
}

function getToolById(id) {
  return tools.find((t) => t.id === id);
}

function getToolByName(name) {
  return tools.find((t) => t.name === name && t.status === 'approved');
}

// Tool definitions formatted for the Inference Port chat/completions "tools" param.
function getApprovedToolDefs() {
  return tools
    .filter((t) => t.status === 'approved')
    .map((t) => ({
      type: 'function',
      function: {
        name: t.name,
        description: t.description,
        parameters: t.parameters && Object.keys(t.parameters).length
          ? t.parameters
          : { type: 'object', properties: {} },
      },
    }));
}

function proposeTool({ name, description, parameters, code, reason }) {
  const safeName = String(name).trim().toLowerCase().replace(/[^a-z0-9_]/g, '_').slice(0, 64);
  const entry = {
    id: nanoid(10),
    name: safeName,
    description: description || '',
    parameters: parameters || { type: 'object', properties: {} },
    code,
    reason: reason || '',
    status: 'pending',
    kind: 'new',
    version: 1,
    createdAt: new Date().toISOString(),
    lastError: null,
    fixesToolId: null,
  };
  tools.push(entry);
  persist();
  return entry;
}

// A fix is proposed as its own pending entry linked back to the broken tool.
// The original tool stays approved and usable (with lastError noted) until
// the fix itself is approved, at which point it replaces the original code.
function proposeFix(originalId, newCode, reason) {
  const original = getToolById(originalId);
  if (!original) throw new Error(`No tool with id ${originalId}`);
  const entry = {
    id: nanoid(10),
    name: original.name,
    description: original.description,
    parameters: original.parameters,
    code: newCode,
    reason: reason || 'Automatic fix for a runtime error',
    status: 'pending',
    kind: 'fix',
    version: (original.version || 1) + 1,
    createdAt: new Date().toISOString(),
    lastError: null,
    fixesToolId: originalId,
  };
  tools.push(entry);
  persist();
  return entry;
}

function approveTool(id) {
  const entry = getToolById(id);
  if (!entry) throw new Error(`No tool with id ${id}`);
  entry.status = 'approved';

  if (entry.kind === 'fix' && entry.fixesToolId) {
    const original = getToolById(entry.fixesToolId);
    if (original) {
      original.code = entry.code;
      original.version = entry.version;
      original.lastError = null;
      original.status = 'approved';
      // The fix entry itself is folded into the original; drop the duplicate.
      tools = tools.filter((t) => t.id !== entry.id);
      persist();
      return original;
    }
  }
  persist();
  return entry;
}

function rejectTool(id, reason) {
  const entry = getToolById(id);
  if (!entry) throw new Error(`No tool with id ${id}`);
  entry.status = 'rejected';
  entry.rejectReason = reason || '';
  if (entry.kind === 'fix') {
    // Reject the fix but leave the original tool as-is (still broken, still approved
    // so the agent can decide whether to try a different fix or a different approach).
    // We snapshot a copy before removing it from the persisted list so the caller
    // still gets a "rejected" object back for display purposes.
    const snapshot = { ...entry };
    tools = tools.filter((t) => t.id !== entry.id);
    persist();
    return snapshot;
  }
  persist();
  return entry;
}

function recordError(id, error) {
  const entry = getToolById(id);
  if (!entry) return;
  entry.lastError = { message: error.message, at: new Date().toISOString() };
  persist();
}

module.exports = {
  BASE_DIR,
  usingPersistentStorage,
  listTools,
  getToolById,
  getToolByName,
  getApprovedToolDefs,
  proposeTool,
  proposeFix,
  approveTool,
  rejectTool,
  recordError,
};