import { Router, type IRouter } from "express";
import { eq, ilike, desc, sql } from "drizzle-orm";
import { db, toolsTable, ratingsTable } from "@workspace/db";
import {
  ListToolsQueryParams,
  CreateToolBody,
  GetToolParams,
  UpdateToolParams,
  UpdateToolBody,
  DeleteToolParams,
} from "@workspace/api-zod";
import { requireAuth } from "../middleware/auth";

const router: IRouter = Router();

function buildToolWithStats(tool: typeof toolsTable.$inferSelect, ratings: { usefulness: number; usability: number }[]) {
  const ratingCount = ratings.length;
  const avgUsefulness = ratingCount > 0
    ? ratings.reduce((s, r) => s + r.usefulness, 0) / ratingCount
    : null;
  const avgUsability = ratingCount > 0
    ? ratings.reduce((s, r) => s + r.usability, 0) / ratingCount
    : null;
  const avgCombined = avgUsefulness != null && avgUsability != null
    ? (avgUsefulness + avgUsability) / 2
    : null;
  return { ...tool, ratingCount, avgUsefulness, avgUsability, avgCombined };
}

router.get("/tools", async (req, res): Promise<void> => {
  const parsed = ListToolsQueryParams.safeParse(req.query);
  if (!parsed.success) {
    res.status(400).json({ error: parsed.error.message });
    return;
  }
  const { category, search, sort } = parsed.data;

  let query = db.select().from(toolsTable).$dynamic();
  if (category) {
    query = query.where(eq(toolsTable.category, category));
  }
  if (search) {
    query = query.where(ilike(toolsTable.name, `%${search}%`));
  }

  const tools = await query.orderBy(desc(toolsTable.createdAt));

  const toolIds = tools.map((t) => t.id);
  let allRatings: { toolId: number; usefulness: number; usability: number }[] = [];
  if (toolIds.length > 0) {
    allRatings = await db
      .select({ toolId: ratingsTable.toolId, usefulness: ratingsTable.usefulness, usability: ratingsTable.usability })
      .from(ratingsTable)
      .where(sql`${ratingsTable.toolId} = ANY(${sql`ARRAY[${sql.join(toolIds.map(id => sql`${id}`), sql`, `)}]::int[]`})`);
  }

  const ratingsByTool = new Map<number, { usefulness: number; usability: number }[]>();
  for (const r of allRatings) {
    const arr = ratingsByTool.get(r.toolId) ?? [];
    arr.push({ usefulness: r.usefulness, usability: r.usability });
    ratingsByTool.set(r.toolId, arr);
  }

  let result = tools.map((t) => buildToolWithStats(t, ratingsByTool.get(t.id) ?? []));

  if (sort === "top_rated") {
    result = result.sort((a, b) => (b.avgCombined ?? 0) - (a.avgCombined ?? 0));
  } else if (sort === "most_reviewed") {
    result = result.sort((a, b) => b.ratingCount - a.ratingCount);
  }

  res.json(result);
});

router.post("/tools", requireAuth, async (req, res): Promise<void> => {
  const parsed = CreateToolBody.safeParse(req.body);
  if (!parsed.success) {
    res.status(400).json({ error: parsed.error.message });
    return;
  }

  const [tool] = await db.insert(toolsTable).values({
    name: parsed.data.name,
    description: parsed.data.description,
    category: parsed.data.category,
    websiteUrl: parsed.data.websiteUrl ?? null,
    iconUrl: parsed.data.iconUrl ?? null,
    features: parsed.data.features ?? [],
    tags: parsed.data.tags ?? [],
  }).returning();

  res.status(201).json(tool);
});

router.get("/tools/:id", async (req, res): Promise<void> => {
  const params = GetToolParams.safeParse(req.params);
  if (!params.success) {
    res.status(400).json({ error: params.error.message });
    return;
  }

  const [tool] = await db.select().from(toolsTable).where(eq(toolsTable.id, params.data.id));
  if (!tool) {
    res.status(404).json({ error: "Tool not found" });
    return;
  }

  const ratings = await db
    .select({ usefulness: ratingsTable.usefulness, usability: ratingsTable.usability })
    .from(ratingsTable)
    .where(eq(ratingsTable.toolId, params.data.id));

  res.json(buildToolWithStats(tool, ratings));
});

router.patch("/tools/:id", requireAuth, async (req, res): Promise<void> => {
  const params = UpdateToolParams.safeParse(req.params);
  if (!params.success) {
    res.status(400).json({ error: params.error.message });
    return;
  }

  const parsed = UpdateToolBody.safeParse(req.body);
  if (!parsed.success) {
    res.status(400).json({ error: parsed.error.message });
    return;
  }

  const updateData: Record<string, unknown> = {};
  if (parsed.data.name !== undefined) updateData.name = parsed.data.name;
  if (parsed.data.description !== undefined) updateData.description = parsed.data.description;
  if (parsed.data.category !== undefined) updateData.category = parsed.data.category;
  if (parsed.data.websiteUrl !== undefined) updateData.websiteUrl = parsed.data.websiteUrl;
  if (parsed.data.iconUrl !== undefined) updateData.iconUrl = parsed.data.iconUrl;
  if (parsed.data.features !== undefined) updateData.features = parsed.data.features;
  if (parsed.data.tags !== undefined) updateData.tags = parsed.data.tags;

  const [tool] = await db
    .update(toolsTable)
    .set(updateData)
    .where(eq(toolsTable.id, params.data.id))
    .returning();

  if (!tool) {
    res.status(404).json({ error: "Tool not found" });
    return;
  }

  res.json(tool);
});

router.delete("/tools/:id", requireAuth, async (req, res): Promise<void> => {
  const params = DeleteToolParams.safeParse(req.params);
  if (!params.success) {
    res.status(400).json({ error: params.error.message });
    return;
  }

  const [tool] = await db.delete(toolsTable).where(eq(toolsTable.id, params.data.id)).returning();
  if (!tool) {
    res.status(404).json({ error: "Tool not found" });
    return;
  }

  res.sendStatus(204);
});

router.get("/categories", async (_req, res): Promise<void> => {
  const rows = await db
    .selectDistinct({ category: toolsTable.category })
    .from(toolsTable)
    .orderBy(toolsTable.category);
  res.json(rows.map((r) => r.category));
});

router.get("/features/all", async (_req, res): Promise<void> => {
  const tools = await db.select({ features: toolsTable.features }).from(toolsTable);
  const featureSet = new Set<string>();
  for (const t of tools) {
    for (const f of t.features ?? []) {
      if (f && f.trim()) featureSet.add(f.trim());
    }
  }
  res.json([...featureSet].sort());
});

export default router;