import { NextRequest, NextResponse } from "next/server";
import { db, isDatabaseAvailable } from "@/lib/db";
import { ensureDatabaseInitialized } from "@/lib/db/init";
import { projects } from "@/lib/schema/db";
import { eq, and } from "drizzle-orm";
import { getCurrentUser } from "@/lib/auth/session";
import { requireCsrf } from "@/lib/auth/csrf";
import { sanitizeText } from "@/lib/ingest/sanitize";
import { isProActive } from "@/lib/billing/access";
import {
  resolveGuestContext,
  applyGuestCookie,
  type GuestContext,
} from "@/lib/auth/guest";

export const runtime = "nodejs";

const PROJECT_NAME_MAX_LENGTH = 120;
const PROJECT_COLORS = ["slate", "blue", "emerald", "amber", "rose", "violet"];

async function resolveScope(req: NextRequest): Promise<{
  user: Awaited<ReturnType<typeof getCurrentUser>>;
  userId: string;
  guest: GuestContext | null;
}> {
  const user = await getCurrentUser(req);
  if (user) return { user, userId: user.id, guest: null };

  const guest = resolveGuestContext(req);
  return { user: null, userId: guest.bucket, guest };
}

function isProUser(user: Awaited<ReturnType<typeof getCurrentUser>>): boolean {
  return isProActive(user);
}

/** GET /api/projects/[id] — single project, ownership-checked, left ungated like the list endpoint. */
export async function GET(req: NextRequest, { params }: { params: Promise<{ id: string }> }) {
  try {
    const { id } = await params;
    const dbAvailable = await isDatabaseAvailable();
    if (!dbAvailable) {
      return NextResponse.json({ error: "Database unavailable." }, { status: 503 });
    }

    await ensureDatabaseInitialized();
    const scope = await resolveScope(req);

    const rows = await db
      .select()
      .from(projects)
      .where(and(eq(projects.id, id), eq(projects.userId, scope.userId)))
      .limit(1);

    if (rows.length === 0) {
      return applyGuestCookie(
        NextResponse.json({ error: "Project not found." }, { status: 404 }),
        scope.guest
      );
    }

    const p = rows[0];
    return applyGuestCookie(
      NextResponse.json({
        success: true,
        project: {
          id: p.id,
          name: p.name,
          color: p.color,
          createdAt: p.createdAt.toISOString(),
          updatedAt: p.updatedAt.toISOString(),
        },
      }),
      scope.guest
    );
  } catch (error: any) {
    console.error("GET /api/projects/[id] error:", error);
    return NextResponse.json({ error: "Failed to load project." }, { status: 500 });
  }
}

/** PATCH /api/projects/[id] — rename / recolor. Pro-only, ownership-checked. */
export async function PATCH(req: NextRequest, { params }: { params: Promise<{ id: string }> }) {
  try {
    const csrfBlocked = requireCsrf(req);
    if (csrfBlocked) return csrfBlocked;

    const { id } = await params;
    const dbAvailable = await isDatabaseAvailable();
    if (!dbAvailable) {
      return NextResponse.json({ error: "Database unavailable." }, { status: 503 });
    }

    await ensureDatabaseInitialized();
    const scope = await resolveScope(req);

    if (!isProUser(scope.user)) {
      return NextResponse.json({ error: "pro_required" }, { status: 402 });
    }

    const existing = await db
      .select({ id: projects.id })
      .from(projects)
      .where(and(eq(projects.id, id), eq(projects.userId, scope.userId)))
      .limit(1);
    if (existing.length === 0) {
      return applyGuestCookie(
        NextResponse.json({ error: "Project not found." }, { status: 404 }),
        scope.guest
      );
    }

    const body = await req.json().catch(() => null);
    const updates: { name?: string; color?: string | null; updatedAt: Date } = {
      updatedAt: new Date(),
    };
    if (typeof body?.name === "string") {
      const name = sanitizeText(body.name, PROJECT_NAME_MAX_LENGTH);
      if (!name) {
        return NextResponse.json({ error: "Project name is required." }, { status: 400 });
      }
      updates.name = name;
    }
    if (body?.color !== undefined) {
      updates.color = PROJECT_COLORS.includes(body.color) ? body.color : null;
    }

    const [updated] = await db
      .update(projects)
      .set(updates)
      .where(eq(projects.id, id))
      .returning();

    return applyGuestCookie(
      NextResponse.json({
        success: true,
        project: {
          id: updated.id,
          name: updated.name,
          color: updated.color,
          createdAt: updated.createdAt.toISOString(),
          updatedAt: updated.updatedAt.toISOString(),
        },
      }),
      scope.guest
    );
  } catch (error: any) {
    if (error?.code === "23505") {
      return NextResponse.json(
        { error: "A project with this name already exists." },
        { status: 409 }
      );
    }
    console.error("PATCH /api/projects/[id] error:", error);
    return NextResponse.json({ error: "Failed to update project." }, { status: 500 });
  }
}

/** DELETE /api/projects/[id] — Pro-only, ownership-checked. Receipts detach via ON DELETE SET NULL. */
export async function DELETE(req: NextRequest, { params }: { params: Promise<{ id: string }> }) {
  try {
    const csrfBlocked = requireCsrf(req);
    if (csrfBlocked) return csrfBlocked;

    const { id } = await params;
    const dbAvailable = await isDatabaseAvailable();
    if (!dbAvailable) {
      return NextResponse.json({ error: "Database unavailable." }, { status: 503 });
    }

    await ensureDatabaseInitialized();
    const scope = await resolveScope(req);

    if (!isProUser(scope.user)) {
      return NextResponse.json({ error: "pro_required" }, { status: 402 });
    }

    const existing = await db
      .select({ id: projects.id })
      .from(projects)
      .where(and(eq(projects.id, id), eq(projects.userId, scope.userId)))
      .limit(1);
    if (existing.length === 0) {
      return applyGuestCookie(
        NextResponse.json({ error: "Project not found." }, { status: 404 }),
        scope.guest
      );
    }

    await db.delete(projects).where(eq(projects.id, id));

    return applyGuestCookie(NextResponse.json({ success: true }), scope.guest);
  } catch (error: any) {
    console.error("DELETE /api/projects/[id] error:", error);
    return NextResponse.json({ error: "Failed to delete project." }, { status: 500 });
  }
}