import { NextResponse } from "next/server";
import { getSupabaseAdmin } from "@/lib/admin";
import { requireAdmin } from "@/lib/apiAuth";
import type { CreditTransaction } from "@/types/billing";

export async function GET(request: Request) {
  const authResult = await requireAdmin(request);
  if (authResult instanceof NextResponse) return authResult;

  const supabase = getSupabaseAdmin();
  const { searchParams } = new URL(request.url);
  const orgId = searchParams.get("orgId");
  const page = parseInt(searchParams.get("page") || "1");
  const limit = parseInt(searchParams.get("limit") || "20");
  const offset = (page - 1) * limit;

  try {
    if (orgId) {
      // Get specific org's credit balance and transaction history
      const [orgResult, transactionsResult] = await Promise.all([
        supabase
          .from("organizations")
          .select("id, name, credit_balance")
          .eq("id", orgId)
          .single(),
        supabase
          .from("credit_transactions")
          .select(
            "*, creator:users!credit_transactions_created_by_fkey(id, email, name)",
            { count: "exact" }
          )
          .eq("organization_id", orgId)
          .order("created_at", { ascending: false })
          .range(offset, offset + limit - 1),
      ]);

      if (orgResult.error) throw orgResult.error;

      return NextResponse.json({
        organization: orgResult.data,
        transactions: (transactionsResult.data || []) as unknown as CreditTransaction[],
        pagination: {
          page,
          limit,
          total: transactionsResult.count || 0,
          pages: Math.ceil((transactionsResult.count || 0) / limit),
        },
      });
    }

    // List all organizations with credit balances
    const { data: orgs, count, error } = await supabase
      .from("organizations")
      .select("id, name, credit_balance, subscription_tier", { count: "exact" })
      .order("credit_balance", { ascending: false })
      .range(offset, offset + limit - 1);

    if (error) throw error;

    return NextResponse.json({
      organizations: orgs || [],
      pagination: { page, limit, total: count || 0, pages: Math.ceil((count || 0) / limit) },
    });
  } catch (error) {
    console.error("Error fetching credits:", error);
    return NextResponse.json({ error: "Failed to fetch credits" }, { status: 500 });
  }
}

export async function POST(request: Request) {
  const authResult = await requireAdmin(request);
  if (authResult instanceof NextResponse) return authResult;

  const supabase = getSupabaseAdmin();

  try {
    const body = await request.json();
    const { organization_id, amount, type, reason, notes } = body;

    if (!organization_id || amount === undefined || !type || !reason) {
      return NextResponse.json(
        { error: "organization_id, amount, type, and reason are required" },
        { status: 400 }
      );
    }

    if (!["credit", "debit"].includes(type)) {
      return NextResponse.json({ error: "type must be 'credit' or 'debit'" }, { status: 400 });
    }

    // Get current balance
    const { data: org, error: orgError } = await supabase
      .from("organizations")
      .select("id, name, credit_balance")
      .eq("id", organization_id)
      .single();

    if (orgError || !org) {
      return NextResponse.json({ error: "Organization not found" }, { status: 404 });
    }

    const absAmount = Math.abs(Math.round(amount));
    const signedAmount = type === "credit" ? absAmount : -absAmount;
    const currentBalance = typeof org.credit_balance === "number" ? org.credit_balance : 0;
    const newBalance = currentBalance + signedAmount;

    if (newBalance < 0) {
      return NextResponse.json(
        { error: `Insufficient balance. Current: ${currentBalance}, debit: ${absAmount}` },
        { status: 400 }
      );
    }

    // Insert transaction and update balance atomically
    const { data, error: txError } = await supabase
      .from("credit_transactions")
      .insert({
        organization_id,
        amount: signedAmount,
        balance_after: newBalance,
        type,
        reason,
        notes,
        created_by: authResult.userId,
      })
      .select()
      .single();

    if (txError) throw txError;
    const transaction = data as unknown as CreditTransaction;

    const { error: updateError } = await supabase
      .from("organizations")
      .update({ credit_balance: newBalance })
      .eq("id", organization_id);

    if (updateError) throw updateError;

    return NextResponse.json({
      transaction,
      new_balance: newBalance,
      organization: { id: org.id, name: org.name },
    });
  } catch (error) {
    console.error("Error processing credit transaction:", error);
    return NextResponse.json({ error: "Failed to process credit transaction" }, { status: 500 });
  }
}