import { Router } from "express";
import { db } from "@workspace/db";
import { clientsTable, tasksTable, usersTable } from "@workspace/db";
import { eq, ilike, count, and, inArray, isNotNull } from "drizzle-orm";
import { requireManagerOrAdmin, requireAdmin, requireAuth, AuthRequest } from "../middleware/auth.js";
import { getTaskVisibilityFilter, User, isAdmin, isTeamLead, canAccessAllTeams, isMember } from "../lib/auth-utils.js";
import { logAudit } from "../lib/audit-logger.js";
import { z } from "zod";
import { invalidateDashboardCache } from "./dashboard.js";


const router = Router();

function serializeClient(
  client: typeof clientsTable.$inferSelect,
  extras: Record<string, unknown> = {}
) {
  return {
    ...client,
    createdAt: client.createdAt.toISOString(),
    updatedAt: client.updatedAt.toISOString(),
    ...extras,
  };
}

router.get("/clients", async (req: AuthRequest, res) => {
  try {
    const user = req.user as User;
    const { search, isActive } = req.query as { search?: string; isActive?: string };
    const conditions = [];
    if (search) conditions.push(ilike(clientsTable.name, `%${search}%`));
    if (isActive !== undefined) conditions.push(eq(clientsTable.isActive, isActive === "true"));

    let clients: (typeof clientsTable.$inferSelect)[] = [];
    if (canAccessAllTeams(user)) {
      // Admins and Head of Team see all clients
      clients = await db.select().from(clientsTable)
        .where(conditions.length > 0 ? and(...conditions) : undefined)
        .orderBy(clientsTable.name);
    } else {
      // Team Leads and Members only see clients they have tasks for (based on their visibility)
      const visibilityFilter = getTaskVisibilityFilter(user);
      const taskClientIds = await db.select({ clientId: tasksTable.clientId })
        .from(tasksTable)
        .where(and(isNotNull(tasksTable.clientId), visibilityFilter));
      
      const uniqueIds = [...new Set(taskClientIds.map(t => t.clientId).filter(Boolean))] as number[];
      if (uniqueIds.length === 0) {
        clients = [];
      } else {
        clients = await db.select().from(clientsTable)
          .where(and(inArray(clientsTable.id, uniqueIds), ...conditions))
          .orderBy(clientsTable.name);
      }
    }

    const visibilityFilter = getTaskVisibilityFilter(user);

    const taskCounts = await db.select({
      clientId: tasksTable.clientId,
      total: count(),
    }).from(tasksTable)
      .where(visibilityFilter)
      .groupBy(tasksTable.clientId);

    const activeCounts = await db.select({
      clientId: tasksTable.clientId,
      cnt: count(),
    }).from(tasksTable)
      .where(and(eq(tasksTable.status, "in_progress"), visibilityFilter))
      .groupBy(tasksTable.clientId);

    const completedCounts = await db.select({
      clientId: tasksTable.clientId,
      cnt: count(),
    }).from(tasksTable)
      .where(and(eq(tasksTable.status, "completed"), visibilityFilter))
      .groupBy(tasksTable.clientId);

    const totalMap: Record<number, number> = {};
    const activeMap: Record<number, number> = {};
    const completedMap: Record<number, number> = {};

    taskCounts.forEach(r => { if (r.clientId) totalMap[r.clientId] = Number(r.total); });
    activeCounts.forEach(r => { if (r.clientId) activeMap[r.clientId] = Number(r.cnt); });
    completedCounts.forEach(r => { if (r.clientId) completedMap[r.clientId] = Number(r.cnt); });

    const result = clients.map(c => serializeClient(c, {
      totalTasks: totalMap[c.id] ?? 0,
      activeTasks: activeMap[c.id] ?? 0,
      completedTasks: completedMap[c.id] ?? 0,
    }));

    res.json(result);
  } catch (err) {
    req.log.error({ err }, "Failed to list clients");
    res.status(500).json({ error: "Internal server error" });
  }
});

const createClientSchema = z.object({
  name: z.string().trim().min(1, "اسم العميل مطلوب"),
  email: z.string().trim().email("بريد إلكتروني غير صالح").optional().or(z.literal("")),
  phone: z.string().trim().regex(/^\+?[0-9\s\-()]{7,20}$/, "رقم هاتف غير صالح").optional().or(z.literal("")),
  assignedTeam: z.string().trim().optional(),
  industry: z.string().trim().optional(),
  notes: z.string().trim().optional(),
});

router.post("/clients", requireAuth, requireManagerOrAdmin, async (req: AuthRequest, res) => {
  try {
    const user = req.user as User;
    if (!user) { res.status(401).json({ error: "Unauthorized" }); return; }

    if (isMember(user)) {
      res.status(403).json({ error: "Forbidden: members cannot create clients" });
      return;
    }

    const parseResult = createClientSchema.safeParse(req.body);
    if (!parseResult.success) {
      res.status(400).json({ error: parseResult.error.errors[0].message });
      return;
    }

    const { name, email, phone, assignedTeam, industry, notes } = parseResult.data;

    if (assignedTeam) {
      const teamUsers = await db.select().from(usersTable).where(eq(usersTable.team, assignedTeam));
      if (teamUsers.length === 0) {
        res.status(400).json({ error: "Assigned team does not exist" });
        return;
      }

      if (!isAdmin(user)) {
        if (assignedTeam !== user.team) {
          res.status(403).json({ error: "Forbidden: You can only create clients for your team" });
          return;
        }
      }
    }

    const clientNotes = [
      notes,
      email ? `Email: ${email}` : null,
      phone ? `Phone: ${phone}` : null,
      assignedTeam ? `Team: ${assignedTeam}` : null,
    ].filter(Boolean).join("\n");

    const [client] = await db.insert(clientsTable).values({
      name,
      industry: industry ?? null,
      notes: clientNotes,
      isActive: true,
      createdByUserId: user.id,
    }).returning();

    logAudit({
      userId: user.id,
      action: "client_created",
      entityType: "client",
      entityId: client.id,
      details: {
        clientId: client.id,
        name: client.name,
        email,
        phone: phone ?? null,
        assignedTeam,
        industry: client.industry,
        notes: notes ?? null,
        isActive: client.isActive,
      },
      req,
    });

    invalidateDashboardCache();
    res.status(201).json(serializeClient(client, { totalTasks: 0, activeTasks: 0, completedTasks: 0 }));
  } catch (err) {
    req.log.error({ err: err instanceof Error ? err.message : String(err) }, "Failed to create client");
    res.status(500).json({ error: "Internal server error" });
  }
});

router.get("/clients/:id", async (req: AuthRequest, res) => {
  try {
    const user = req.user as User;
    const visibilityFilter = getTaskVisibilityFilter(user);
    const id = parseInt(req.params.id as string);
    const [client] = await db.select().from(clientsTable).where(eq(clientsTable.id, id));
    if (!client) { res.status(404).json({ error: "Client not found" }); return; }

    const tasks = await db.select().from(tasksTable).where(
      and(eq(tasksTable.clientId, id), visibilityFilter)
    ).orderBy(tasksTable.createdAt);

    const total = tasks.length;
    const active = tasks.filter(t => t.status === "in_progress").length;
    const completed = tasks.filter(t => t.status === "completed").length;

    const serializedTasks = tasks.map(t => ({
      ...t,
      dueDate: t.dueDate ? t.dueDate.toISOString() : null,
      completedAt: t.completedAt ? t.completedAt.toISOString() : null,
      createdAt: t.createdAt.toISOString(),
      updatedAt: t.updatedAt.toISOString(),
      createdByUser: null,
      assignedUser: null,
      commentCount: 0,
      clientName: client.name,
    }));

    res.json(serializeClient(client, {
      totalTasks: total,
      activeTasks: active,
      completedTasks: completed,
      tasks: serializedTasks,
    }));
  } catch (err) {
    req.log.error({ err }, "Failed to get client");
    res.status(500).json({ error: "Internal server error" });
  }
});

const updateClientSchema = z.object({
  name: z.string().trim().min(1, "اسم العميل مطلوب").optional(),
  email: z.string().trim().email("بريد إلكتروني غير صالح").optional().or(z.literal("")),
  phone: z.string().trim().regex(/^\+?[0-9\s\-()]{7,20}$/, "رقم هاتف غير صالح").optional().or(z.literal("")),
  assignedTeam: z.string().trim().optional(),
  industry: z.string().trim().optional(),
  notes: z.string().trim().optional(),
  isActive: z.boolean().optional(),
});

const updateClientParamsSchema = z.object({
  id: z.coerce.number().int().positive("معرف العميل غير صالح"),
});

router.patch("/clients/:id", requireAuth, requireManagerOrAdmin, async (req: AuthRequest, res) => {
  try {
    const user = req.user as User;
    if (!user) { res.status(401).json({ error: "Unauthorized" }); return; }

    if (isMember(user)) {
      res.status(403).json({ error: "Forbidden: members cannot update clients" });
      return;
    }

    const paramsResult = updateClientParamsSchema.safeParse({ id: req.params.id });
    if (!paramsResult.success) {
      res.status(400).json({ error: paramsResult.error.errors[0].message });
      return;
    }
    const { id } = paramsResult.data;

    const parseResult = updateClientSchema.safeParse(req.body);
    if (!parseResult.success) {
      res.status(400).json({ error: parseResult.error.errors[0].message });
      return;
    }
    const body = parseResult.data;

    const [existingClient] = await db.select().from(clientsTable).where(eq(clientsTable.id, id));
    if (!existingClient) { res.status(404).json({ error: "Client not found" }); return; }

    const oldNotesStr = existingClient.notes ?? "";
    let oldEmail: string | null = null;
    let oldPhone: string | null = null;
    let oldTeam: string | null = null;
    const emMatch = oldNotesStr.match(/Email:\s*([^\n]+)/);
    if (emMatch) oldEmail = emMatch[1].trim();
    const phMatch = oldNotesStr.match(/Phone:\s*([^\n]+)/);
    if (phMatch) oldPhone = phMatch[1].trim();
    const tmMatch = oldNotesStr.match(/Team:\s*([^\n]+)/);
    if (tmMatch) oldTeam = tmMatch[1].trim();
    const oldPureNotes = oldNotesStr.split("\n").filter(l => !l.startsWith("Email:") && !l.startsWith("Phone:") && !l.startsWith("Team:")).join("\n").trim();

    if (!isAdmin(user)) {
      if (oldTeam && oldTeam !== user.team) {
        res.status(403).json({ error: "Forbidden: You can only update clients in your team" });
        return;
      }
    }

    if (body.assignedTeam !== undefined) {
      const teamUsers = await db.select().from(usersTable).where(eq(usersTable.team, body.assignedTeam));
      if (teamUsers.length === 0) {
        res.status(400).json({ error: "Assigned team does not exist" });
        return;
      }
    }

    // Track changes for audit log
    const changes: any = {};
    if (body.name !== undefined && body.name !== existingClient.name) changes.name = { old: existingClient.name, new: body.name };
    if (body.email !== undefined && body.email !== oldEmail) changes.email = { old: oldEmail, new: body.email };
    if (body.phone !== undefined && body.phone !== oldPhone) changes.phone = { old: oldPhone, new: body.phone };
    if (body.assignedTeam !== undefined && body.assignedTeam !== oldTeam) changes.assignedTeam = { old: oldTeam, new: body.assignedTeam };
    if (body.industry !== undefined && body.industry !== existingClient.industry) changes.industry = { old: existingClient.industry, new: body.industry };
    if (body.notes !== undefined && body.notes.trim() !== oldPureNotes) changes.notes = { old: oldPureNotes, new: body.notes.trim() };
    if (body.isActive !== undefined && body.isActive !== existingClient.isActive) changes.isActive = { old: existingClient.isActive, new: body.isActive };

    let updatedNotes = body.notes !== undefined ? body.notes : existingClient.notes;
    if (body.email !== undefined || body.phone !== undefined || body.assignedTeam !== undefined) {
      const lines = oldNotesStr.split("\n").filter(l => !l.startsWith("Email:") && !l.startsWith("Phone:") && !l.startsWith("Team:"));
      
      let emailVal = body.email;
      if (emailVal === undefined) emailVal = oldEmail ?? undefined;
      let phoneVal = body.phone;
      if (phoneVal === undefined) phoneVal = oldPhone ?? undefined;
      let teamVal = body.assignedTeam;
      if (teamVal === undefined) teamVal = oldTeam ?? undefined;

      const newMeta = [
        emailVal ? `Email: ${emailVal}` : null,
        phoneVal ? `Phone: ${phoneVal}` : null,
        teamVal ? `Team: ${teamVal}` : null,
      ].filter(Boolean);

      updatedNotes = [...lines, ...newMeta].filter(Boolean).join("\n");
    }

    const updates: Partial<typeof clientsTable.$inferInsert> = {
      updatedAt: new Date(),
    };
    if (body.name !== undefined) updates.name = body.name;
    if (body.industry !== undefined) updates.industry = body.industry ?? null;
    if (updatedNotes !== undefined) updates.notes = updatedNotes ?? null;
    if (body.isActive !== undefined) updates.isActive = body.isActive;

    const [client] = await db.update(clientsTable).set(updates).where(eq(clientsTable.id, id)).returning();
    if (!client) { res.status(404).json({ error: "Client not found" }); return; }

    invalidateDashboardCache();

    if (Object.keys(changes).length > 0) {
      logAudit({
        userId: user.id,
        action: "client_updated",
        entityType: "client",
        entityId: client.id,
        details: {
          clientId: client.id,
          name: client.name,
          changes,
        },
        req,
      });
    }

    const [{ cnt: total }] = await db.select({ cnt: count() }).from(tasksTable).where(eq(tasksTable.clientId, id));
    const [{ cnt: active }] = await db.select({ cnt: count() }).from(tasksTable).where(and(eq(tasksTable.clientId, id), eq(tasksTable.status, "in_progress")));
    const [{ cnt: completed }] = await db.select({ cnt: count() }).from(tasksTable).where(and(eq(tasksTable.clientId, id), eq(tasksTable.status, "completed")));

    res.json(serializeClient(client, {
      totalTasks: Number(total),
      activeTasks: Number(active),
      completedTasks: Number(completed),
    }));
  } catch (err) {
    req.log.error({ err: err instanceof Error ? err.message : String(err) }, "Failed to update client");
    res.status(500).json({ error: "Internal server error" });
  }
});

router.delete("/clients/:id", requireAuth, requireAdmin, async (req: AuthRequest, res) => {
  try {
    const user = req.user as User;
    if (!user) { res.status(401).json({ error: "Unauthorized" }); return; }

    const id = parseInt(req.params.id as string);
    if (isNaN(id)) {
      res.status(400).json({ error: "معرف العميل غير صالح" });
      return;
    }

    const [client] = await db.select().from(clientsTable).where(eq(clientsTable.id, id));
    if (!client) {
      res.status(404).json({ error: "العميل غير موجود" });
      return;
    }

    // Delete all tasks associated with this client first (satisfies foreign key constraint)
    await db.delete(tasksTable).where(eq(tasksTable.clientId, id));

    // Delete client
    await db.delete(clientsTable).where(eq(clientsTable.id, id));

    invalidateDashboardCache();

    logAudit({
      userId: user.id,
      action: "client_deleted",
      entityType: "client",
      entityId: id,
      details: {
        clientId: id,
        name: client.name,
      },
      req,
    });

    res.status(200).json({ success: true, message: "تم حذف العميل بنجاح" });
  } catch (err) {
    req.log.error({ err: err instanceof Error ? err.message : String(err) }, "Failed to delete client");
    res.status(500).json({ error: "Internal server error" });
  }
});

export default router;