import { Router } from "express";
import { and, eq, like, or } from "drizzle-orm";
import { z } from "zod";
import { db } from "../db/client.js";
import { scheduledTasks, servers } from "../db/schema.js";
import { requireAuth, requireRole } from "../auth/middleware.js";
import { recordAudit } from "../services/audit.js";
import { asyncHandler } from "../utils/asyncHandler.js";

export const tasksRouter = Router();
tasksRouter.use(requireAuth);

const TASK_COLUMNS = {
  id: scheduledTasks.id,
  serverId: scheduledTasks.serverId,
  serverName: servers.name,
  scheduleType: scheduledTasks.scheduleType,
  origin: scheduledTasks.origin,
  name: scheduledTasks.name,
  command: scheduledTasks.command,
  scheduleExpression: scheduledTasks.scheduleExpression,
  source: scheduledTasks.source,
  enabled: scheduledTasks.enabled,
  nextRunAt: scheduledTasks.nextRunAt,
  isStale: scheduledTasks.isStale,
  firstSeenAt: scheduledTasks.firstSeenAt,
  lastSeenAt: scheduledTasks.lastSeenAt,
};

tasksRouter.get("/", asyncHandler(async (req, res) => {
  const serverId = req.query.serverId ? Number(req.query.serverId) : undefined;
  const scheduleType = typeof req.query.scheduleType === "string" ? req.query.scheduleType : undefined;
  const search = typeof req.query.search === "string" ? req.query.search.trim() : undefined;
  const includeStale = req.query.includeStale === "true";

  const conditions = [];
  if (serverId && Number.isInteger(serverId)) {
    conditions.push(eq(scheduledTasks.serverId, serverId));
  }
  if (scheduleType) {
    conditions.push(eq(scheduledTasks.scheduleType, scheduleType));
  }
  if (!includeStale) {
    conditions.push(eq(scheduledTasks.isStale, false));
  }
  if (search) {
    const pattern = `%${search}%`;
    conditions.push(or(like(scheduledTasks.name, pattern), like(scheduledTasks.command, pattern)));
  }

  const rows = await db
    .select(TASK_COLUMNS)
    .from(scheduledTasks)
    .innerJoin(servers, eq(scheduledTasks.serverId, servers.id))
    .where(conditions.length > 0 ? and(...conditions) : undefined)
    .orderBy(servers.name, scheduledTasks.scheduleType, scheduledTasks.name);

  res.json({ tasks: rows });
}));

const manualTaskSchema = z.object({
  serverId: z.number().int(),
  scheduleType: z.enum(["cron", "systemd_timer", "docker", "backup", "update", "n8n_workflow", "manual"]),
  name: z.string().min(1).max(200),
  command: z.string().max(1000).optional(),
  scheduleExpression: z.string().max(200).optional(),
  nextRunAt: z.string().optional(),
  enabled: z.boolean().optional(),
});

tasksRouter.post("/", requireRole("operator"), asyncHandler(async (req, res) => {
  const parsed = manualTaskSchema.safeParse(req.body);
  if (!parsed.success) {
    return res.status(400).json({ error: "invalid_body", details: parsed.error.flatten() });
  }

  const server = await db.query.servers.findFirst({ where: eq(servers.id, parsed.data.serverId) });
  if (!server) {
    return res.status(400).json({ error: "unknown_server" });
  }

  const now = new Date().toISOString();
  const [created] = await db
    .insert(scheduledTasks)
    .values({
      serverId: parsed.data.serverId,
      scheduleType: parsed.data.scheduleType,
      origin: "manual",
      name: parsed.data.name,
      command: parsed.data.command,
      scheduleExpression: parsed.data.scheduleExpression,
      nextRunAt: parsed.data.nextRunAt,
      enabled: parsed.data.enabled ?? true,
      firstSeenAt: now,
      lastSeenAt: now,
    })
    .returning({ id: scheduledTasks.id });

  await recordAudit({
    actor: req.currentUser!,
    category: "task",
    action: "create",
    targetType: "scheduled_task",
    targetId: created.id,
    detail: { name: parsed.data.name, serverId: parsed.data.serverId },
  });

  const [task] = await db
    .select(TASK_COLUMNS)
    .from(scheduledTasks)
    .innerJoin(servers, eq(scheduledTasks.serverId, servers.id))
    .where(eq(scheduledTasks.id, created.id));
  res.status(201).json({ task });
}));

const manualTaskUpdateSchema = manualTaskSchema.omit({ serverId: true }).partial();

tasksRouter.patch("/:id", requireRole("operator"), asyncHandler(async (req, res) => {
  const id = Number(req.params.id);
  if (!Number.isInteger(id)) return res.status(400).json({ error: "invalid_id" });

  const parsed = manualTaskUpdateSchema.safeParse(req.body);
  if (!parsed.success) {
    return res.status(400).json({ error: "invalid_body", details: parsed.error.flatten() });
  }

  const existing = await db.query.scheduledTasks.findFirst({ where: eq(scheduledTasks.id, id) });
  if (!existing) return res.status(404).json({ error: "not_found" });
  if (existing.origin !== "manual") {
    return res.status(403).json({ error: "not_editable", message: "Only manually entered tasks can be edited." });
  }

  await db
    .update(scheduledTasks)
    .set({ ...parsed.data, lastSeenAt: new Date().toISOString() })
    .where(eq(scheduledTasks.id, id));

  await recordAudit({
    actor: req.currentUser!,
    category: "task",
    action: "update",
    targetType: "scheduled_task",
    targetId: id,
    detail: { name: existing.name },
  });

  const [task] = await db
    .select(TASK_COLUMNS)
    .from(scheduledTasks)
    .innerJoin(servers, eq(scheduledTasks.serverId, servers.id))
    .where(eq(scheduledTasks.id, id));
  res.json({ task });
}));

tasksRouter.delete("/:id", requireRole("operator"), asyncHandler(async (req, res) => {
  const id = Number(req.params.id);
  if (!Number.isInteger(id)) return res.status(400).json({ error: "invalid_id" });

  const existing = await db.query.scheduledTasks.findFirst({ where: eq(scheduledTasks.id, id) });
  if (!existing) return res.status(404).json({ error: "not_found" });
  if (existing.origin !== "manual") {
    return res.status(403).json({ error: "not_editable", message: "Only manually entered tasks can be deleted." });
  }

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

  await recordAudit({
    actor: req.currentUser!,
    category: "task",
    action: "delete",
    targetType: "scheduled_task",
    targetId: id,
    detail: { name: existing.name },
  });

  res.status(204).end();
}));