import { Router } from "express";
import { db, nextId } from "../db.js";

export const productsRouter: Router = Router();

type CreateBody = {
  sku: string;
  // strain identity: either link to an existing strain via id, or supply a
  // name and the server creates / matches one. Strain.name doubles as the
  // product's display name.
  strainId?: string | null;
  strainName?: string;
  brandId?: string | null;
  type: string;
  kind: "bulk" | "discrete";
  defaultThc?: number;
  defaultCbd?: number;
  defaultTotalCannabinoids?: number;
};

productsRouter.post("/products", (req, res) => {
  const body = req.body as CreateBody;
  if (!body.sku?.trim()) return res.status(400).json({ error: "sku required" });
  if (!body.type) return res.status(400).json({ error: "type required" });
  if (body.kind !== "bulk" && body.kind !== "discrete") {
    return res.status(400).json({ error: "kind must be bulk or discrete" });
  }
  if (!body.strainId && !body.strainName?.trim()) {
    return res.status(400).json({ error: "strainId or strainName required" });
  }

  const sku = body.sku.trim();
  const todayIso = new Date().toISOString().slice(0, 10);

  const existingSku = db
    .prepare<[string], { id: string }>("SELECT id FROM products WHERE sku = ?")
    .get(sku);
  if (existingSku) {
    return res.status(409).json({ error: "sku already exists", id: existingSku.id });
  }

  const id = nextId("pdt", "products");

  try {
    const tx = db.transaction(() => {
      let strainId = body.strainId ?? null;

      if (!strainId) {
        const strainName = body.strainName!.trim();
        const found = db
          .prepare<[string], { id: string }>(
            `SELECT id FROM strains WHERE name = ? COLLATE NOCASE`,
          )
          .get(strainName);
        if (found) {
          strainId = found.id;
        } else {
          strainId = nextId("str", "strains");
          db.prepare(
            `INSERT INTO strains (
               id, name,
               default_thc, default_cbd, default_total_cannabinoids,
               created_at
             ) VALUES (?, ?, ?, ?, ?, ?)`,
          ).run(
            strainId,
            strainName,
            body.defaultThc ?? null,
            body.defaultCbd ?? null,
            body.defaultTotalCannabinoids ?? null,
            todayIso,
          );
        }
      }

      db.prepare(
        `INSERT INTO products (id, sku, strain_id, brand_id, type, kind, created_at)
         VALUES (?, ?, ?, ?, ?, ?, ?)`,
      ).run(id, sku, strainId, body.brandId ?? null, body.type, body.kind, todayIso);
    });
    tx();
  } catch (err) {
    const msg = err instanceof Error ? err.message : "";
    if (msg.includes("UNIQUE")) {
      return res.status(409).json({ error: "sku already exists" });
    }
    throw err;
  }

  res.json({ id });
});

type UpdateBody = Partial<{
  sku: string;
  type: string;
  kind: "bulk" | "discrete";
  strainId: string | null;
  strainName: string;
  brandId: string | null;
}>;

productsRouter.patch("/products/:id", (req, res) => {
  const { id } = req.params;
  const body = req.body as UpdateBody;

  const existing = db
    .prepare<
      [string],
      { id: string; sku: string; type: string; kind: string; strain_id: string; brand_id: string | null }
    >(
      `SELECT id, sku, type, kind, strain_id, brand_id FROM products WHERE id = ?`,
    )
    .get(id);
  if (!existing) return res.status(404).json({ error: "product not found" });

  const nextSku = typeof body.sku === "string" && body.sku.trim() ? body.sku.trim() : existing.sku;
  if (nextSku !== existing.sku) {
    const duplicate = db
      .prepare<[string, string], { id: string }>("SELECT id FROM products WHERE sku = ? AND id != ?")
      .get(nextSku, id);
    if (duplicate) return res.status(409).json({ error: "sku already exists" });
  }

  const nextType = typeof body.type === "string" && body.type ? body.type : existing.type;
  const nextKind: "bulk" | "discrete" =
    body.kind === "bulk" || body.kind === "discrete"
      ? body.kind
      : (existing.kind as "bulk" | "discrete");
  const nextBrandId =
    body.brandId === undefined ? existing.brand_id : body.brandId;

  // Strain handling: prefer explicit strainId; else if strainName given,
  // match-by-name (case-insensitive) or create a new strain.
  let nextStrainId = existing.strain_id;
  const todayIso = new Date().toISOString().slice(0, 10);
  if (body.strainId !== undefined && body.strainId) {
    nextStrainId = body.strainId;
  } else if (typeof body.strainName === "string" && body.strainName.trim()) {
    const name = body.strainName.trim();
    const found = db
      .prepare<[string], { id: string }>(
        `SELECT id FROM strains WHERE name = ? COLLATE NOCASE`,
      )
      .get(name);
    if (found) {
      nextStrainId = found.id;
    } else {
      nextStrainId = nextId("str", "strains");
      db.prepare(
        `INSERT INTO strains (id, name, created_at) VALUES (?, ?, ?)`,
      ).run(nextStrainId, name, todayIso);
    }
  }

  db.prepare(
    `UPDATE products SET sku = ?, type = ?, kind = ?, strain_id = ?, brand_id = ? WHERE id = ?`,
  ).run(nextSku, nextType, nextKind, nextStrainId, nextBrandId, id);

  res.json({ ok: true });
});

productsRouter.delete("/products/:id", (req, res) => {
  const { id } = req.params;
  const inUse = db
    .prepare<[string], { n: number }>(
      `SELECT COUNT(*) AS n FROM inventory_items WHERE product_id = ?`,
    )
    .get(id)!.n;
  if (inUse > 0) {
    return res
      .status(409)
      .json({ error: `product has ${inUse} inventory item${inUse === 1 ? "" : "s"}` });
  }
  const result = db.prepare(`DELETE FROM products WHERE id = ?`).run(id);
  if (result.changes === 0) return res.status(404).json({ error: "product not found" });
  res.json({ ok: true });
});

// Strain management — kept here since strains are catalog cousins of products.
productsRouter.patch("/strains/:id", (req, res) => {
  const { id } = req.params;
  const body = req.body as Partial<{
    name: string;
    defaultThc: number | null;
    defaultCbd: number | null;
    defaultTotalCannabinoids: number | null;
    notes: string | null;
  }>;

  const existing = db
    .prepare<
      [string],
      {
        id: string;
        name: string;
        default_thc: number | null;
        default_cbd: number | null;
        default_total_cannabinoids: number | null;
        notes: string | null;
      }
    >(
      `SELECT id, name, default_thc, default_cbd, default_total_cannabinoids, notes
       FROM strains WHERE id = ?`,
    )
    .get(id);
  if (!existing) return res.status(404).json({ error: "strain not found" });

  const nextName =
    typeof body.name === "string" && body.name.trim() ? body.name.trim() : existing.name;
  const nextThc =
    body.defaultThc === undefined ? existing.default_thc : body.defaultThc;
  const nextCbd =
    body.defaultCbd === undefined ? existing.default_cbd : body.defaultCbd;
  const nextTotal =
    body.defaultTotalCannabinoids === undefined
      ? existing.default_total_cannabinoids
      : body.defaultTotalCannabinoids;
  const nextNotes = body.notes === undefined ? existing.notes : body.notes;

  try {
    db.prepare(
      `UPDATE strains SET
         name = ?, default_thc = ?, default_cbd = ?, default_total_cannabinoids = ?, notes = ?
       WHERE id = ?`,
    ).run(nextName, nextThc, nextCbd, nextTotal, nextNotes, id);
    res.json({ ok: true });
  } catch (err) {
    const msg = err instanceof Error ? err.message : "";
    if (msg.includes("UNIQUE")) {
      return res.status(409).json({ error: "another strain already uses that name" });
    }
    throw err;
  }
});