import { NextResponse } from "next/server";
import { getRequestDetailsDb } from "@/lib/requestDetailsDb";
import { getProviderNodes } from "@/lib/localDb";
import { AI_PROVIDERS, getProviderByAlias } from "@/shared/constants/providers";

/**
 * GET /api/usage/providers
 * Returns list of unique providers from request details
 */
export async function GET() {
  try {
    const db = await getRequestDetailsDb();

    const stmt = db.prepare(`
      SELECT DISTINCT provider
      FROM request_details
      WHERE provider IS NOT NULL AND provider != ''
      ORDER BY provider ASC
    `);

    const rows = stmt.all();

    // Fetch all provider nodes to get names for custom providers
    const providerNodes = await getProviderNodes();
    const nodeMap = {};
    for (const node of providerNodes) {
      nodeMap[node.id] = node.name;
    }

    const providers = rows.map(row => {
      const providerId = row.provider;

      // Try to find name from various sources
      let name = providerId;

      // 1. Check if it's a custom provider node
      if (nodeMap[providerId]) {
        name = nodeMap[providerId];
      }
      // 2. Check predefined providers
      else {
        const providerConfig = getProviderByAlias(providerId) || AI_PROVIDERS[providerId];
        if (providerConfig?.name) {
          name = providerConfig.name;
        }
      }

      return {
        id: providerId,
        name
      };
    });

    return NextResponse.json({ providers });
  } catch (error) {
    console.error("[API] Failed to get providers:", error);
    return NextResponse.json(
      { error: "Failed to fetch providers" },
      { status: 500 }
    );
  }
}