import { createFileRoute, Link } from "@tanstack/react-router";
import { useEffect, useMemo, useState } from "react";
import { ProtectedLayout } from "@/components/protected-layout";
import { PageContainer, PageHeader } from "@/components/app-shell";
import { Card, CardContent } from "@/components/ui/card";
import { Button } from "@/components/ui/button";
import { Input } from "@/components/ui/input";
import { Badge } from "@/components/ui/badge";
import { Tabs, TabsList, TabsTrigger } from "@/components/ui/tabs";
import { Checkbox } from "@/components/ui/checkbox";
import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/components/ui/select";
import { supabase } from "@/integrations/supabase/client";
import { useAuth } from "@/lib/auth";
import { toast } from "sonner";
import { Plus, Search, Mail, Phone, Building2, ChevronRight, Edit, Trash2, Briefcase, Users, Archive, ArchiveRestore, X } from "lucide-react";
import { ContactFormDialog, CONTACT_TYPES, type ContactRecord } from "@/components/contacts/contact-form-dialog";
import { setArchived } from "@/lib/archive";

export const Route = createFileRoute("/contacts/")({
  component: () => (
    <ProtectedLayout>
      <ContactsIndex />
    </ProtectedLayout>
  ),
});

interface ContactRow extends Required<Pick<ContactRecord, "name">>, ContactRecord {
  id: string;
  created_by: string | null;
  case_links: number;
  client_links: number;
  archived_at: string | null;
}

function ContactsIndex() {
  const { user, isAdmin } = useAuth();
  const [rows, setRows] = useState<ContactRow[]>([]);
  const [loading, setLoading] = useState(true);
  const [q, setQ] = useState("");
  const [typeFilter, setTypeFilter] = useState<string>("all");
  const [view, setView] = useState<"active" | "archived">("active");
  const [editing, setEditing] = useState<ContactRecord | null>(null);
  const [open, setOpen] = useState(false);
  const [selected, setSelected] = useState<Set<string>>(new Set());
  const [bulkType, setBulkType] = useState<string>("");
  const [letter, setLetter] = useState<string>("all");
  const [visibleLimit, setVisibleLimit] = useState<number>(100);

  const load = async () => {
    setLoading(true);
    // Paginate to bypass Supabase's 1000-row default limit
    const fetchAllContacts = async () => {
      const pageSize = 1000;
      let from = 0;
      const all: any[] = [];
      while (true) {
        const { data, error } = await supabase
          .from("contacts")
          .select("*")
          .order("name")
          .range(from, from + pageSize - 1);
        if (error) return { data: all, error };
        if (!data || data.length === 0) break;
        all.push(...data);
        if (data.length < pageSize) break;
        from += pageSize;
      }
      return { data: all, error: null as any };
    };
    const fetchAllLinks = async (table: "case_contacts" | "client_contacts") => {
      const pageSize = 1000;
      let from = 0;
      const all: any[] = [];
      while (true) {
        const { data, error } = await supabase
          .from(table)
          .select("contact_id")
          .range(from, from + pageSize - 1);
        if (error || !data || data.length === 0) break;
        all.push(...data);
        if (data.length < pageSize) break;
        from += pageSize;
      }
      return { data: all };
    };
    const [{ data, error }, { data: cc }, { data: clc }] = await Promise.all([
      fetchAllContacts(),
      fetchAllLinks("case_contacts"),
      fetchAllLinks("client_contacts"),
    ]);
    if (error) toast.error(error.message);
    const caseCounts = new Map<string, number>();
    (cc ?? []).forEach((r: any) => caseCounts.set(r.contact_id, (caseCounts.get(r.contact_id) ?? 0) + 1));
    const clientCounts = new Map<string, number>();
    (clc ?? []).forEach((r: any) => clientCounts.set(r.contact_id, (clientCounts.get(r.contact_id) ?? 0) + 1));
    setRows(
      (data ?? []).map((c: any) => ({
        ...c,
        case_links: caseCounts.get(c.id) ?? 0,
        client_links: clientCounts.get(c.id) ?? 0,
      })),
    );
    setLoading(false);
  };

  useEffect(() => {
    load();
  }, []);

  const letterOf = (name: string | null | undefined) => {
    const ch = (name?.[0] ?? "#").toUpperCase();
    return /[A-Z]/.test(ch) ? ch : "#";
  };

  const preLetterFiltered = useMemo(() => {
    const term = q.trim().toLowerCase();
    return rows.filter((r) => {
      if (view === "archived" ? !r.archived_at : !!r.archived_at) return false;
      if (typeFilter !== "all" && r.contact_type !== typeFilter) return false;
      if (!term) return true;
      return (
        r.name.toLowerCase().includes(term) ||
        (r.company ?? "").toLowerCase().includes(term) ||
        (r.email ?? "").toLowerCase().includes(term) ||
        (r.phone ?? "").toLowerCase().includes(term)
      );
    });
  }, [rows, q, typeFilter, view]);

  const letterCounts = useMemo(() => {
    const counts: Record<string, number> = { all: preLetterFiltered.length };
    for (const r of preLetterFiltered) {
      const l = letterOf(r.name);
      counts[l] = (counts[l] ?? 0) + 1;
    }
    return counts;
  }, [preLetterFiltered]);

  const filtered = useMemo(() => {
    if (letter === "all") return preLetterFiltered;
    return preLetterFiltered.filter((r) => letterOf(r.name) === letter);
  }, [preLetterFiltered, letter]);

  // Reset paging window when filters change
  useEffect(() => {
    setVisibleLimit(100);
  }, [q, typeFilter, view, letter]);

  const visibleRows = useMemo(() => filtered.slice(0, visibleLimit), [filtered, visibleLimit]);
  const hasMore = filtered.length > visibleRows.length;

  const grouped = useMemo(() => {
    const map = new Map<string, ContactRow[]>();
    for (const r of visibleRows) {
      const l = letterOf(r.name);
      if (!map.has(l)) map.set(l, []);
      map.get(l)!.push(r);
    }
    return Array.from(map.entries()).sort(([a], [b]) => {
      if (a === "#") return 1;
      if (b === "#") return -1;
      return a.localeCompare(b);
    });
  }, [visibleRows]);

  const archivedCount = rows.filter((r) => r.archived_at).length;
  const activeCount = rows.length - archivedCount;

  const typeCounts = useMemo(() => {
    const base = rows.filter((r) => (view === "archived" ? !!r.archived_at : !r.archived_at));
    const counts: Record<string, number> = { all: base.length };
    for (const t of CONTACT_TYPES) {
      counts[t.value] = base.filter((r) => (r.contact_type ?? "other") === t.value).length;
    }
    return counts;
  }, [rows, view]);

  const remove = async (id: string, name: string) => {
    if (!confirm(`Delete contact "${name}"? This will also remove all case and client links.`)) return;
    const { error } = await supabase.from("contacts").delete().eq("id", id);
    if (error) {
      toast.error(error.message);
      return;
    }
    toast.success("Contact deleted");
    setRows((r) => r.filter((x) => x.id !== id));
  };

  const onArchive = async (id: string, archived: boolean) => {
    if (await setArchived("contacts", id, archived)) load();
  };

  const startNew = () => {
    setEditing(null);
    setOpen(true);
  };
  const startEdit = (c: ContactRow) => {
    setEditing(c);
    setOpen(true);
  };

  const toggleOne = (id: string) => {
    setSelected((s) => {
      const next = new Set(s);
      if (next.has(id)) next.delete(id);
      else next.add(id);
      return next;
    });
  };
  const toggleAllVisible = () => {
    const ids = visibleRows.map((r) => r.id);
    const allSelected = ids.every((id) => selected.has(id));
    setSelected((s) => {
      const next = new Set(s);
      if (allSelected) ids.forEach((id) => next.delete(id));
      else ids.forEach((id) => next.add(id));
      return next;
    });
  };
  const clearSelection = () => setSelected(new Set());

  const bulkArchive = async (archived: boolean) => {
    const ids = Array.from(selected);
    if (!ids.length) return;
    const patch = { archived_at: archived ? new Date().toISOString() : null };
    const { error } = await (supabase.from("contacts") as any).update(patch).in("id", ids);
    if (error) {
      toast.error(error.message);
      return;
    }
    toast.success(`${ids.length} contact${ids.length === 1 ? "" : "s"} ${archived ? "archived" : "restored"}`);
    clearSelection();
    load();
  };

  const bulkDelete = async () => {
    const ids = Array.from(selected);
    if (!ids.length) return;
    if (!confirm(`Delete ${ids.length} contact${ids.length === 1 ? "" : "s"}? This will also remove all case and client links.`)) return;
    const { error } = await supabase.from("contacts").delete().in("id", ids);
    if (error) {
      toast.error(error.message);
      return;
    }
    toast.success(`${ids.length} contact${ids.length === 1 ? "" : "s"} deleted`);
    clearSelection();
    load();
  };

  const bulkChangeType = async (newType: string) => {
    const ids = Array.from(selected);
    if (!ids.length || !newType) return;
    const { error } = await supabase.from("contacts").update({ contact_type: newType }).in("id", ids);
    if (error) {
      toast.error(error.message);
      return;
    }
    const label = CONTACT_TYPES.find((t) => t.value === newType)?.label ?? newType;
    toast.success(`${ids.length} contact${ids.length === 1 ? "" : "s"} changed to ${label}`);
    setBulkType("");
    clearSelection();
    load();
  };

  const visibleIds = visibleRows.map((r) => r.id);
  const allVisibleSelected = visibleIds.length > 0 && visibleIds.every((id) => selected.has(id));
  const someVisibleSelected = visibleIds.some((id) => selected.has(id));

  return (
    <PageContainer>
      <PageHeader
        title="Contacts"
        description="Shared directory of opposing counsel, witnesses, vendors, experts, and other contacts."
        actions={
          <Button onClick={startNew}>
            <Plus className="h-4 w-4 mr-2" /> New contact
          </Button>
        }
      />

      <Card className="mb-4">
        <CardContent className="p-4 flex flex-col sm:flex-row gap-3">
          <Tabs value={view} onValueChange={(v) => setView(v as "active" | "archived")}>
            <TabsList>
              <TabsTrigger value="active">Active ({activeCount})</TabsTrigger>
              <TabsTrigger value="archived">Archived ({archivedCount})</TabsTrigger>
            </TabsList>
          </Tabs>
          <div className="relative flex-1">
            <Search className="absolute left-3 top-1/2 -translate-y-1/2 h-4 w-4 text-muted-foreground" />
            <Input
              placeholder="Search name, company, email, phone…"
              value={q}
              onChange={(e) => setQ(e.target.value)}
              className="pl-9"
            />
          </div>
          <select
            value={typeFilter}
            onChange={(e) => setTypeFilter(e.target.value)}
            className="h-9 rounded-md border border-input bg-transparent px-3 text-sm sm:w-56"
          >
            <option value="all">All types</option>
            {CONTACT_TYPES.map((t) => (
              <option key={t.value} value={t.value}>{t.label}</option>
            ))}
          </select>
        </CardContent>
      </Card>

      <div className="mb-4 flex flex-wrap gap-1.5">
        <Button
          size="sm"
          variant={typeFilter === "all" ? "default" : "outline"}
          onClick={() => setTypeFilter("all")}
        >
          All ({typeCounts.all ?? 0})
        </Button>
        {CONTACT_TYPES.map((t) => (
          <Button
            key={t.value}
            size="sm"
            variant={typeFilter === t.value ? "default" : "outline"}
            onClick={() => setTypeFilter(t.value)}
          >
            {t.label} ({typeCounts[t.value] ?? 0})
          </Button>
        ))}
      </div>

      <div className="mb-4 flex flex-wrap gap-1">
        <Button
          size="sm"
          variant={letter === "all" ? "default" : "outline"}
          className="h-8 px-2.5"
          onClick={() => setLetter("all")}
        >
          All ({letterCounts.all ?? 0})
        </Button>
        {"ABCDEFGHIJKLMNOPQRSTUVWXYZ".split("").concat("#").map((L) => {
          const count = letterCounts[L] ?? 0;
          const disabled = count === 0;
          return (
            <Button
              key={L}
              size="sm"
              variant={letter === L ? "default" : "outline"}
              className="h-8 w-8 p-0 text-xs"
              disabled={disabled}
              onClick={() => setLetter(L)}
              title={`${L} (${count})`}
            >
              {L}
            </Button>
          );
        })}
      </div>

      {selected.size > 0 && (
        <Card className="mb-4 border-primary/50 bg-primary/5">
          <CardContent className="p-3 flex flex-wrap items-center gap-2">
            <span className="text-sm font-medium mr-2">
              {selected.size} selected
            </span>
            <Button size="sm" variant="outline" onClick={() => bulkArchive(view !== "archived")}>
              {view === "archived" ? <ArchiveRestore className="h-4 w-4 mr-1.5" /> : <Archive className="h-4 w-4 mr-1.5" />}
              {view === "archived" ? "Restore" : "Archive"}
            </Button>
            <Select value={bulkType} onValueChange={bulkChangeType}>
              <SelectTrigger className="h-8 w-48">
                <SelectValue placeholder="Change type to…" />
              </SelectTrigger>
              <SelectContent>
                {CONTACT_TYPES.map((t) => (
                  <SelectItem key={t.value} value={t.value}>{t.label}</SelectItem>
                ))}
              </SelectContent>
            </Select>
            <Button size="sm" variant="destructive" onClick={bulkDelete}>
              <Trash2 className="h-4 w-4 mr-1.5" /> Delete
            </Button>
            <Button size="sm" variant="ghost" onClick={clearSelection} className="ml-auto">
              <X className="h-4 w-4 mr-1.5" /> Clear
            </Button>
          </CardContent>
        </Card>
      )}

      <Card>
        <CardContent className="p-0">
          {filtered.length > 0 && !loading && (
            <div className="px-4 py-2 border-b flex items-center gap-3 bg-muted/30">
              <Checkbox
                checked={allVisibleSelected ? true : someVisibleSelected ? "indeterminate" : false}
                onCheckedChange={toggleAllVisible}
                aria-label="Select all visible"
              />
              <span className="text-xs text-muted-foreground">
                Showing {visibleRows.length} of {filtered.length}
              </span>
            </div>
          )}
          {loading ? (
            <p className="p-6 text-sm text-muted-foreground">Loading…</p>
          ) : filtered.length === 0 ? (
            <p className="p-6 text-sm text-muted-foreground text-center">
              {rows.length === 0 ? "No contacts yet." : view === "archived" ? "No archived contacts." : "No contacts match your filters."}
            </p>
          ) : (
            <div className="divide-y">
              {grouped.map(([letter, items]) => (
                <div key={letter}>
                  <div className="px-4 py-1.5 bg-muted/50 text-xs font-semibold text-muted-foreground">
                    {letter}
                  </div>
                  <ul className="divide-y">
                    {items.map((c) => {
                      const typeLabel = CONTACT_TYPES.find((t) => t.value === c.contact_type)?.label ?? c.contact_type;
                      const canEdit = isAdmin || c.created_by === user?.id;
                      return (
                        <li key={c.id} className={`px-4 py-3 hover:bg-muted/40 transition-colors ${selected.has(c.id) ? "bg-primary/5" : ""}`}>
                          <div className="flex items-center gap-3">
                            <Checkbox
                              checked={selected.has(c.id)}
                              onCheckedChange={() => toggleOne(c.id)}
                              aria-label={`Select ${c.name}`}
                            />
                            <Link
                              to="/contacts/$contactId"
                              params={{ contactId: c.id }}
                              className="flex-1 min-w-0 flex items-center gap-3"
                            >
                              <div className="min-w-0 flex-1">
                                <div className="flex items-center gap-2 flex-wrap">
                                  <span className="font-medium truncate">{c.name}</span>
                                  <Badge variant="outline" className="text-[10px]">{typeLabel}</Badge>
                                  {c.title && <span className="text-xs text-muted-foreground">{c.title}</span>}
                                </div>
                                <div className="mt-1 flex flex-wrap gap-x-4 gap-y-0.5 text-xs text-muted-foreground">
                                  {c.company && <span className="flex items-center gap-1.5"><Building2 className="h-3 w-3" />{c.company}</span>}
                                  {c.email && <span className="flex items-center gap-1.5"><Mail className="h-3 w-3" />{c.email}</span>}
                                  {c.phone && <span className="flex items-center gap-1.5"><Phone className="h-3 w-3" />{c.phone}</span>}
                                </div>
                              </div>
                              <div className="hidden md:flex flex-col items-end text-[11px] text-muted-foreground gap-0.5 mr-2">
                                {c.case_links > 0 && <span className="flex items-center gap-1"><Briefcase className="h-3 w-3" />{c.case_links} case{c.case_links === 1 ? "" : "s"}</span>}
                                {c.client_links > 0 && <span className="flex items-center gap-1"><Users className="h-3 w-3" />{c.client_links} client{c.client_links === 1 ? "" : "s"}</span>}
                              </div>
                              <ChevronRight className="h-4 w-4 text-muted-foreground" />
                            </Link>
                            <div className="flex gap-1">
                              <Button
                                variant="ghost"
                                size="icon"
                                title={c.archived_at ? "Restore" : "Archive"}
                                onClick={() => onArchive(c.id, !c.archived_at)}
                              >
                                {c.archived_at ? <ArchiveRestore className="h-4 w-4" /> : <Archive className="h-4 w-4" />}
                              </Button>
                              {canEdit && (
                                <>
                                  <Button variant="ghost" size="icon" onClick={() => startEdit(c)}>
                                    <Edit className="h-4 w-4" />
                                  </Button>
                                  <Button variant="ghost" size="icon" onClick={() => remove(c.id, c.name)}>
                                    <Trash2 className="h-4 w-4 text-destructive" />
                                  </Button>
                                </>
                              )}
                            </div>
                          </div>
                        </li>
                      );
                    })}
                  </ul>
                </div>
              ))}
            </div>
          )}
          {!loading && hasMore && (
            <div className="px-4 py-3 border-t flex items-center justify-center">
              <Button variant="outline" size="sm" onClick={() => setVisibleLimit((n) => n + 100)}>
                Load 100 more ({filtered.length - visibleRows.length} remaining)
              </Button>
            </div>
          )}
        </CardContent>
      </Card>

      <ContactFormDialog
        open={open}
        onOpenChange={setOpen}
        contact={editing}
        onSaved={() => load()}
      />
    </PageContainer>
  );
}