/**
 * Pricing tools: get_pricing, compare_prices, get_competitor_stock
 */
import type { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { z } from "zod";
import { pool } from "../db.js";

export async function registerPricingTools(server: McpServer): Promise<void> {
  // --- Tool: get_pricing ---
  server.tool(
    "get_pricing",
    "Get current prices and availability across all sources for a specific transceiver. Includes price history if requested.",
    {
      part_number: z.string().describe("Part number or slug, e.g. 'qsfp28-lr4' or 'SFP-10G-LR'"),
      vendor: z.string().optional().describe("Filter to specific vendor only"),
      include_history: z.boolean().default(false).describe("Include 30-day price history"),
    },
    async ({ part_number, vendor, include_history }) => {
      // Find transceiver
      const txResult = await pool.query(
        `SELECT t.id, t.slug, t.standard_name, t.form_factor, t.speed, t.reach_label
         FROM transceivers t
         WHERE t.slug ILIKE $1 OR t.part_number ILIKE $1 OR t.standard_name ILIKE $1
         LIMIT 1`,
        [`%${part_number}%`]
      );

      if (txResult.rows.length === 0) {
        return {
          content: [{ type: "text", text: `No transceiver found for "${part_number}".` }],
        };
      }

      const tx = txResult.rows[0];
      const vendorCondition = vendor ? `AND v.name ILIKE $2` : "";
      const baseParams: unknown[] = vendor ? [tx.id, `%${vendor}%`] : [tx.id];

      // Current prices (latest per vendor)
      const currentPrices = await pool.query(
        `SELECT DISTINCT ON (po.source_vendor_id)
                v.name as vendor, po.price, po.currency, po.stock_level,
                po.quantity_available, po.url, po.time
         FROM price_observations po
         JOIN vendors v ON v.id = po.source_vendor_id
         WHERE po.transceiver_id = $1 ${vendorCondition}
         ORDER BY po.source_vendor_id, po.time DESC`,
        baseParams
      );

      let history = null;
      if (include_history) {
        const histResult = await pool.query(
          `SELECT v.name as vendor, po.price, po.currency, po.stock_level, po.time
           FROM price_observations po
           JOIN vendors v ON v.id = po.source_vendor_id
           WHERE po.transceiver_id = $1 ${vendorCondition}
             AND po.time > NOW() - INTERVAL '30 days'
           ORDER BY po.time DESC
           LIMIT 200`,
          baseParams
        );
        history = histResult.rows;
      }

      const response = {
        transceiver: {
          slug: tx.slug,
          standard: tx.standard_name,
          form_factor: tx.form_factor,
          speed: tx.speed,
          reach: tx.reach_label,
        },
        current_prices: currentPrices.rows,
        cheapest: currentPrices.rows.length > 0
          ? currentPrices.rows.reduce((min, r) => r.price < min.price ? r : min)
          : null,
        history: include_history ? history : undefined,
      };

      return {
        content: [{ type: "text", text: JSON.stringify(response, null, 2) }],
      };
    }
  );

  // --- Tool: compare_prices ---
  server.tool(
    "compare_prices",
    "Compare prices across all vendors for a transceiver. Shows savings opportunities vs competitors.",
    {
      transceiver_query: z.string().describe("Free text or part number to search for"),
      competitors: z.array(z.string()).optional().describe("Limit to specific competitors"),
    },
    async ({ transceiver_query, competitors }) => {
      const vendorFilter = competitors && competitors.length > 0
        ? `AND v.name ILIKE ANY(ARRAY[${competitors.map((_, i) => `$${i + 2}`).join(",")}])`
        : "";

      const values: unknown[] = [transceiver_query];
      if (competitors) {
        competitors.forEach((c) => values.push(`%${c}%`));
      }

      const result = await pool.query(
        `SELECT t.slug, t.standard_name, t.form_factor, t.speed, t.reach_label,
                v.name as vendor, v.type,
                po.price, po.currency, po.stock_level, po.time
         FROM price_observations po
         JOIN transceivers t ON t.id = po.transceiver_id
         JOIN vendors v ON v.id = po.source_vendor_id
         WHERE (t.standard_name ILIKE $1 OR t.slug ILIKE $1)
           ${vendorFilter}
           AND po.time = (
             SELECT MAX(time) FROM price_observations
             WHERE transceiver_id = t.id AND source_vendor_id = v.id
           )
         ORDER BY t.slug, po.price ASC`,
        values
      );

      if (result.rows.length === 0) {
        return {
          content: [{ type: "text", text: `No pricing data found for "${transceiver_query}".` }],
        };
      }

      // Group by transceiver
      const grouped: Record<string, {
        transceiver: { slug: string; standard: string; form_factor: string; speed: string; reach: string };
        prices: Array<{ vendor: string; type: string; price: number; currency: string; stock: string }>;
        min_price: number;
        max_price: number;
        savings_vs_max: number;
      }> = {};

      for (const row of result.rows) {
        if (!grouped[row.slug]) {
          grouped[row.slug] = {
            transceiver: {
              slug: row.slug,
              standard: row.standard_name,
              form_factor: row.form_factor,
              speed: row.speed,
              reach: row.reach_label,
            },
            prices: [],
            min_price: Infinity,
            max_price: 0,
            savings_vs_max: 0,
          };
        }
        grouped[row.slug].prices.push({
          vendor: row.vendor,
          type: row.type,
          price: parseFloat(row.price),
          currency: row.currency,
          stock: row.stock_level,
        });
        grouped[row.slug].min_price = Math.min(grouped[row.slug].min_price, parseFloat(row.price));
        grouped[row.slug].max_price = Math.max(grouped[row.slug].max_price, parseFloat(row.price));
      }

      for (const slug of Object.keys(grouped)) {
        const g = grouped[slug];
        g.savings_vs_max = Math.round((1 - g.min_price / g.max_price) * 100);
      }

      return {
        content: [{
          type: "text",
          text: JSON.stringify({ comparisons: Object.values(grouped) }, null, 2),
        }],
      };
    }
  );

  // --- Tool: get_competitor_stock ---
  server.tool(
    "get_competitor_stock",
    "Check live stock levels at a specific competitor. Useful for identifying sales opportunities when competitor is out of stock.",
    {
      competitor: z.string().describe("Competitor name, e.g. 'FS.COM', 'Optcore', 'ProLabs'"),
      product_query: z.string().optional().describe("Optional product filter"),
      out_of_stock_only: z.boolean().default(false).describe("Only show out-of-stock items (sales opportunities)"),
    },
    async ({ competitor, product_query, out_of_stock_only }) => {
      const conditions = [`v.name ILIKE $1`];
      const values: unknown[] = [`%${competitor}%`];
      let idx = 2;

      if (product_query) {
        conditions.push(`(t.standard_name ILIKE $${idx} OR t.slug ILIKE $${idx})`);
        values.push(`%${product_query}%`);
        idx++;
      }

      if (out_of_stock_only) {
        conditions.push(`po.stock_level IN ('out_of_stock', 'discontinued')`);
      }

      const result = await pool.query(
        `SELECT DISTINCT ON (t.id)
                v.name as competitor, t.slug, t.standard_name, t.form_factor, t.speed,
                t.reach_label, po.price, po.currency, po.stock_level,
                po.quantity_available, po.time
         FROM price_observations po
         JOIN vendors v ON v.id = po.source_vendor_id
         JOIN transceivers t ON t.id = po.transceiver_id
         WHERE ${conditions.join(" AND ")}
         ORDER BY t.id, po.time DESC
         LIMIT 100`,
        values
      );

      const inStock = result.rows.filter((r) => r.stock_level === "in_stock").length;
      const outOfStock = result.rows.filter((r) =>
        ["out_of_stock", "discontinued"].includes(r.stock_level)
      ).length;

      return {
        content: [{
          type: "text",
          text: JSON.stringify({
            competitor,
            summary: { total: result.rows.length, in_stock: inStock, out_of_stock: outOfStock },
            items: result.rows,
            sales_opportunities: out_of_stock_only
              ? result.rows.length
              : `${outOfStock} items out of stock at ${competitor}`,
          }, null, 2),
        }],
      };
    }
  );
}