require("dotenv").config();
const express = require("express");
const bodyParser = require("body-parser");
const { User, Post, sequelize } = require("./models");

const app = express();
app.use(bodyParser.json());

// Helper to get model by resource name
const models = { users: User, posts: Post };

// Sync DB
sequelize.sync();

// TreeQL-style dynamic GET
app.get("/:resource/:id?/:subresource?", async (req, res) => {
  const { resource, id, subresource } = req.params;
  const Model = models[resource];
  if (!Model) return res.status(404).json({ error: "Resource not found" });

  try {
    if (id) {
      const instance = await Model.findByPk(
        id,
        subresource ? { include: subresource } : {}
      );
      if (!instance) return res.status(404).json({ error: "Not found" });
      if (subresource && instance[subresource]) {
        return res.json(instance[subresource]);
      }
      return res.json(instance);
    } else {
      const all = await Model.findAll();
      return res.json(all);
    }
  } catch (e) {
    return res.status(500).json({ error: e.message });
  }
});

// TreeQL-style POST (create resource or subresource)
app.post("/:resource/:id?/:subresource?", async (req, res) => {
  const { resource, id, subresource } = req.params;
  const Model = models[resource];
  if (!Model) return res.status(404).json({ error: "Resource not found" });

  try {
    if (id && subresource) {
      // e.g. POST /users/1/posts
      const parent = await models[resource].findByPk(id);
      if (!parent) return res.status(404).json({ error: "Parent not found" });
      const childModel = models[subresource];
      if (!childModel)
        return res.status(404).json({ error: "Subresource not found" });
      const child = await childModel.create({ ...req.body, UserId: id });
      return res.status(201).json(child);
    } else {
      // e.g. POST /users
      const instance = await Model.create(req.body);
      return res.status(201).json(instance);
    }
  } catch (e) {
    return res.status(500).json({ error: e.message });
  }
});

// TreeQL-style PUT (update resource)
app.put("/:resource/:id", async (req, res) => {
  const { resource, id } = req.params;
  const Model = models[resource];
  if (!Model) return res.status(404).json({ error: "Resource not found" });

  try {
    const instance = await Model.findByPk(id);
    if (!instance) return res.status(404).json({ error: "Not found" });
    await instance.update(req.body);
    return res.json(instance);
  } catch (e) {
    return res.status(500).json({ error: e.message });
  }
});

// TreeQL-style DELETE (delete resource)
app.delete("/:resource/:id", async (req, res) => {
  const { resource, id } = req.params;
  const Model = models[resource];
  if (!Model) return res.status(404).json({ error: "Resource not found" });

  try {
    const instance = await Model.findByPk(id);
    if (!instance) return res.status(404).json({ error: "Not found" });
    await instance.destroy();
    return res.json({ success: true });
  } catch (e) {
    return res.status(500).json({ error: e.message });
  }
});

const PORT = process.env.PORT || 3000;
app.listen(PORT, () => console.log(`TreeQL API running on port ${PORT}`));