import { createFileRoute } from "@tanstack/react-router";
import { useEffect, useState } from "react";
import { supabase } from "@/integrations/supabase/client";
import { useAuth } from "@/lib/auth";
import { Button } from "@/components/ui/button";
import { Card, CardContent } from "@/components/ui/card";
import { Input } from "@/components/ui/input";
import { Label } from "@/components/ui/label";
import { Textarea } from "@/components/ui/textarea";
import { Checkbox } from "@/components/ui/checkbox";
import { Badge } from "@/components/ui/badge";
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogTitle,
} from "@/components/ui/dialog";
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from "@/components/ui/select";
import {
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableHeader,
  TableRow,
} from "@/components/ui/table";
import { Clock, Loader2, Pencil, Plus, Receipt, Trash2, ClipboardPaste } from "lucide-react";
import { toast } from "sonner";
import { formatCurrency } from "@/lib/format";

export const Route = createFileRoute("/settings/fees")({
  component: FeeSchedulePage,
});

interface FeeItem {
  id: string;
  name: string;
  description: string | null;
  category: "time" | "expense";
  amount: number;
  billable: boolean;
  active: boolean;
  sort_order: number;
}

function FeeSchedulePage() {
  const { user } = useAuth();
  const [items, setItems] = useState<FeeItem[]>([]);
  const [loading, setLoading] = useState(true);
  const [editing, setEditing] = useState<Partial<FeeItem> | null>(null);
  const [importing, setImporting] = useState<"time" | "expense" | null>(null);

  const load = async () => {
    setLoading(true);
    const { data } = await supabase
      .from("fee_schedule_items")
      .select("*")
      .order("category")
      .order("sort_order")
      .order("name");
    setItems((data ?? []) as FeeItem[]);
    setLoading(false);
  };

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

  const remove = async (id: string) => {
    if (!confirm("Delete this fee item?")) return;
    const { error } = await supabase
      .from("fee_schedule_items")
      .delete()
      .eq("id", id);
    if (error) toast.error("Could not delete", { description: error.message });
    else {
      toast.success("Fee item deleted");
      load();
    }
  };

  const timeItems = items.filter((i) => i.category === "time");
  const expenseItems = items.filter((i) => i.category === "expense");

  return (
    <div className="space-y-6 max-w-5xl">
      <div className="flex justify-between items-start gap-4 flex-wrap">
        <p className="text-sm text-muted-foreground max-w-2xl">
          Define reusable billable items. Time fees set the hourly rate when
          logging time; expense fees auto-fill the amount when adding an
          expense. The billable flag becomes the default for new entries.
        </p>
        <Button onClick={() => setEditing({ category: "time", billable: true, active: true, amount: 0 })}>
          <Plus className="h-4 w-4 mr-2" /> Add fee item
        </Button>
      </div>

      <FeeSection
        title="Time fees"
        icon={<Clock className="h-4 w-4 text-muted-foreground" />}
        unit="/ hr"
        items={timeItems}
        loading={loading}
        onEdit={setEditing}
        onDelete={remove}
        onImport={() => setImporting("time")}
      />

      <FeeSection
        title="Expense fees"
        icon={<Receipt className="h-4 w-4 text-muted-foreground" />}
        unit=""
        items={expenseItems}
        loading={loading}
        onEdit={setEditing}
        onDelete={remove}
        onImport={() => setImporting("expense")}
      />

      <FeeEditDialog
        item={editing}
        onClose={() => setEditing(null)}
        onSaved={load}
      />

      <FeeImportDialog
        category={importing}
        userId={user?.id}
        onClose={() => setImporting(null)}
        onSaved={load}
      />
    </div>
  );
}

function FeeSection({
  title,
  icon,
  unit,
  items,
  loading,
  onEdit,
  onDelete,
  onImport,
}: {
  title: string;
  icon: React.ReactNode;
  unit: string;
  items: FeeItem[];
  loading: boolean;
  onEdit: (i: FeeItem) => void;
  onDelete: (id: string) => void;
  onImport: () => void;
}) {
  return (
    <div>
      <div className="flex items-center justify-between mb-2">
        <h3 className="font-serif text-lg flex items-center gap-2">
          {icon}
          {title}
        </h3>
        <Button variant="outline" size="sm" onClick={onImport}>
          <ClipboardPaste className="h-3.5 w-3.5 mr-2" /> Paste import
        </Button>
      </div>
      <Card className="border-border/60">
        <CardContent className="p-0">
          {loading ? (
            <div className="p-8 text-center text-muted-foreground text-sm">
              Loading…
            </div>
          ) : items.length === 0 ? (
            <div className="p-8 text-center text-muted-foreground text-sm">
              No {title.toLowerCase()} configured yet.
            </div>
          ) : (
            <Table>
              <TableHeader>
                <TableRow>
                  <TableHead>Name</TableHead>
                  <TableHead>Description</TableHead>
                  <TableHead className="text-right">Amount</TableHead>
                  <TableHead>Billable</TableHead>
                  <TableHead>Active</TableHead>
                  <TableHead></TableHead>
                </TableRow>
              </TableHeader>
              <TableBody>
                {items.map((i) => (
                  <TableRow key={i.id}>
                    <TableCell className="font-medium">{i.name}</TableCell>
                    <TableCell className="text-muted-foreground max-w-md">
                      {i.description || "—"}
                    </TableCell>
                    <TableCell className="text-right font-mono">
                      {formatCurrency(Number(i.amount))}
                      {unit && (
                        <span className="text-muted-foreground text-xs ml-1">
                          {unit}
                        </span>
                      )}
                    </TableCell>
                    <TableCell>
                      {i.billable ? (
                        <Badge variant="outline" className="text-[10px]">
                          Billable
                        </Badge>
                      ) : (
                        <span className="text-xs text-muted-foreground">No</span>
                      )}
                    </TableCell>
                    <TableCell>
                      {i.active ? (
                        <Badge variant="outline" className="text-[10px]">
                          Active
                        </Badge>
                      ) : (
                        <span className="text-xs text-muted-foreground">
                          Inactive
                        </span>
                      )}
                    </TableCell>
                    <TableCell className="text-right">
                      <Button
                        variant="ghost"
                        size="icon"
                        onClick={() => onEdit(i)}
                      >
                        <Pencil className="h-3.5 w-3.5" />
                      </Button>
                      <Button
                        variant="ghost"
                        size="icon"
                        onClick={() => onDelete(i.id)}
                      >
                        <Trash2 className="h-3.5 w-3.5 text-destructive" />
                      </Button>
                    </TableCell>
                  </TableRow>
                ))}
              </TableBody>
            </Table>
          )}
        </CardContent>
      </Card>
    </div>
  );
}

function FeeEditDialog({
  item,
  onClose,
  onSaved,
}: {
  item: Partial<FeeItem> | null;
  onClose: () => void;
  onSaved: () => void;
}) {
  const { user } = useAuth();
  const [form, setForm] = useState<Partial<FeeItem>>({});
  const [saving, setSaving] = useState(false);

  useEffect(() => {
    if (item) setForm(item);
  }, [item]);

  const submit = async () => {
    if (!form.name?.trim()) return toast.error("Name required");
    if (!form.category) return toast.error("Category required");
    const payload: any = {
      name: form.name.trim(),
      description: form.description?.trim() || null,
      category: form.category,
      amount: Number(form.amount) || 0,
      billable: form.billable ?? true,
      active: form.active ?? true,
      sort_order: form.sort_order ?? 0,
    };
    setSaving(true);
    const { error } = form.id
      ? await supabase
          .from("fee_schedule_items")
          .update(payload)
          .eq("id", form.id)
      : await supabase
          .from("fee_schedule_items")
          .insert({ ...payload, created_by: user?.id });
    setSaving(false);
    if (error) {
      toast.error("Could not save", { description: error.message });
      return;
    }
    toast.success(form.id ? "Fee updated" : "Fee added");
    onClose();
    onSaved();
  };

  return (
    <Dialog open={!!item} onOpenChange={(v) => !v && onClose()}>
      <DialogContent>
        <DialogHeader>
          <DialogTitle className="font-serif">
            {form.id ? "Edit fee item" : "Add fee item"}
          </DialogTitle>
          <DialogDescription>
            Time fees feed the hourly rate dropdown; expense fees feed the
            expense amount picker.
          </DialogDescription>
        </DialogHeader>
        <div className="space-y-3">
          <div className="grid grid-cols-2 gap-3">
            <div className="space-y-1.5">
              <Label className="text-xs">Category</Label>
              <Select
                value={form.category ?? "time"}
                onValueChange={(v) =>
                  setForm({ ...form, category: v as "time" | "expense" })
                }
              >
                <SelectTrigger>
                  <SelectValue />
                </SelectTrigger>
                <SelectContent>
                  <SelectItem value="time">Time (hourly rate)</SelectItem>
                  <SelectItem value="expense">Expense (flat amount)</SelectItem>
                </SelectContent>
              </Select>
            </div>
            <div className="space-y-1.5">
              <Label className="text-xs">
                {form.category === "expense" ? "Amount ($)" : "Rate ($ / hr)"}
              </Label>
              <Input
                type="number"
                step="0.01"
                min="0"
                value={form.amount ?? ""}
                onChange={(e) =>
                  setForm({ ...form, amount: parseFloat(e.target.value) || 0 })
                }
              />
            </div>
          </div>
          <div className="space-y-1.5">
            <Label className="text-xs">Name</Label>
            <Input
              value={form.name ?? ""}
              onChange={(e) => setForm({ ...form, name: e.target.value })}
              placeholder={
                form.category === "expense"
                  ? "e.g. Filing fee"
                  : "e.g. Senior partner rate"
              }
            />
          </div>
          <div className="space-y-1.5">
            <Label className="text-xs">Description (optional)</Label>
            <Textarea
              rows={2}
              value={form.description ?? ""}
              onChange={(e) =>
                setForm({ ...form, description: e.target.value })
              }
            />
          </div>
          <div className="grid grid-cols-3 gap-3">
            <label className="flex items-center gap-2 text-sm">
              <Checkbox
                checked={form.billable ?? true}
                onCheckedChange={(c) =>
                  setForm({ ...form, billable: !!c })
                }
              />
              Billable by default
            </label>
            <label className="flex items-center gap-2 text-sm">
              <Checkbox
                checked={form.active ?? true}
                onCheckedChange={(c) => setForm({ ...form, active: !!c })}
              />
              Active
            </label>
            <div className="space-y-1.5">
              <Label className="text-xs">Sort order</Label>
              <Input
                type="number"
                value={form.sort_order ?? 0}
                onChange={(e) =>
                  setForm({
                    ...form,
                    sort_order: parseInt(e.target.value) || 0,
                  })
                }
              />
            </div>
          </div>
        </div>
        <DialogFooter>
          <Button variant="outline" onClick={onClose}>
            Cancel
          </Button>
          <Button onClick={submit} disabled={saving}>
            {saving && <Loader2 className="h-4 w-4 mr-2 animate-spin" />}
            Save
          </Button>
        </DialogFooter>
      </DialogContent>
    </Dialog>
  );
}

// Parse a tab- or comma-separated row, respecting basic quoted values.
function parseRow(line: string): string[] {
  const out: string[] = [];
  let cur = "";
  let inQuotes = false;
  const sep = line.includes("\t") ? "\t" : ",";
  for (let i = 0; i < line.length; i++) {
    const ch = line[i];
    if (ch === '"') {
      if (inQuotes && line[i + 1] === '"') {
        cur += '"';
        i++;
      } else {
        inQuotes = !inQuotes;
      }
    } else if (ch === sep && !inQuotes) {
      out.push(cur);
      cur = "";
    } else {
      cur += ch;
    }
  }
  out.push(cur);
  return out.map((s) => s.trim());
}

const HEADER_ALIASES: Record<string, string> = {
  name: "name",
  item: "name",
  title: "name",
  description: "description",
  desc: "description",
  notes: "description",
  amount: "amount",
  rate: "amount",
  price: "amount",
  cost: "amount",
  hourly_rate: "amount",
  billable: "billable",
  active: "active",
  enabled: "active",
  sort: "sort_order",
  sort_order: "sort_order",
  order: "sort_order",
};

function parseBool(v: string, fallback: boolean): boolean {
  if (!v) return fallback;
  const s = v.trim().toLowerCase();
  if (["true", "yes", "y", "1", "x"].includes(s)) return true;
  if (["false", "no", "n", "0", ""].includes(s)) return false;
  return fallback;
}

function FeeImportDialog({
  category,
  userId,
  onClose,
  onSaved,
}: {
  category: "time" | "expense" | null;
  userId: string | undefined;
  onClose: () => void;
  onSaved: () => void;
}) {
  const [text, setText] = useState("");
  const [saving, setSaving] = useState(false);

  useEffect(() => {
    if (category) setText("");
  }, [category]);

  const preview = (() => {
    if (!text.trim()) return { rows: [], errors: [] as string[] };
    const lines = text
      .split(/\r?\n/)
      .map((l) => l.trim())
      .filter(Boolean);
    if (lines.length === 0) return { rows: [], errors: [] };

    // Detect header row
    const firstCols = parseRow(lines[0]).map((c) => c.toLowerCase());
    const hasHeader = firstCols.some((c) => c in HEADER_ALIASES);
    const headers = hasHeader
      ? firstCols.map((c) => HEADER_ALIASES[c] ?? c)
      : ["name", "amount", "description"];
    const dataLines = hasHeader ? lines.slice(1) : lines;

    const rows: Array<{
      name: string;
      description: string | null;
      amount: number;
      billable: boolean;
      active: boolean;
      sort_order: number;
    }> = [];
    const errors: string[] = [];

    dataLines.forEach((line, idx) => {
      const cols = parseRow(line);
      const rec: Record<string, string> = {};
      headers.forEach((h, i) => {
        rec[h] = cols[i] ?? "";
      });
      const name = (rec.name ?? "").trim();
      if (!name) {
        errors.push(`Row ${idx + 1}: missing name`);
        return;
      }
      const amountRaw = (rec.amount ?? "").replace(/[$,\s]/g, "");
      const amount = amountRaw === "" ? 0 : Number(amountRaw);
      if (Number.isNaN(amount)) {
        errors.push(`Row ${idx + 1}: invalid amount "${rec.amount}"`);
        return;
      }
      rows.push({
        name,
        description: rec.description?.trim() || null,
        amount,
        billable: parseBool(rec.billable ?? "", true),
        active: parseBool(rec.active ?? "", true),
        sort_order: parseInt(rec.sort_order ?? "0") || 0,
      });
    });

    return { rows, errors };
  })();

  const submit = async () => {
    if (!category) return;
    if (preview.rows.length === 0) {
      toast.error("Nothing to import");
      return;
    }
    setSaving(true);
    const payload = preview.rows.map((r) => ({
      ...r,
      category,
      created_by: userId,
    }));
    const { error } = await supabase
      .from("fee_schedule_items")
      .insert(payload);
    setSaving(false);
    if (error) {
      toast.error("Import failed", { description: error.message });
      return;
    }
    toast.success(`Imported ${payload.length} ${category} fee item${payload.length === 1 ? "" : "s"}`);
    onClose();
    onSaved();
  };

  return (
    <Dialog open={!!category} onOpenChange={(v) => !v && onClose()}>
      <DialogContent className="max-w-2xl">
        <DialogHeader>
          <DialogTitle className="font-serif">
            Paste {category === "expense" ? "expense" : "time"} fee items
          </DialogTitle>
          <DialogDescription>
            Paste rows from a spreadsheet. Tab- or comma-separated. First column
            should be the item name; second column the {category === "expense" ? "amount" : "hourly rate"};
            optional third column the description. A header row is auto-detected
            (supported headers: name, amount/rate, description, billable, active,
            sort_order).
          </DialogDescription>
        </DialogHeader>
        <div className="space-y-3">
          <Textarea
            rows={10}
            value={text}
            onChange={(e) => setText(e.target.value)}
            placeholder={
              category === "expense"
                ? "Filing fee\t450\nService of process\t75\nCertified mail\t12.50"
                : "Senior partner\t450\nAssociate\t275\nParalegal\t125"
            }
            className="font-mono text-xs"
          />
          {text.trim() && (
            <div className="text-xs space-y-1">
              <div className="text-muted-foreground">
                {preview.rows.length} row{preview.rows.length === 1 ? "" : "s"} ready to import
                {preview.errors.length > 0 && (
                  <span className="text-destructive">
                    {" "}· {preview.errors.length} skipped
                  </span>
                )}
              </div>
              {preview.rows.length > 0 && (
                <div className="border rounded p-2 max-h-40 overflow-auto">
                  {preview.rows.slice(0, 8).map((r, i) => (
                    <div key={i} className="flex justify-between gap-3 py-0.5">
                      <span className="truncate">{r.name}</span>
                      <span className="font-mono text-muted-foreground">
                        {formatCurrency(r.amount)}
                      </span>
                    </div>
                  ))}
                  {preview.rows.length > 8 && (
                    <div className="text-muted-foreground text-[10px] pt-1">
                      … and {preview.rows.length - 8} more
                    </div>
                  )}
                </div>
              )}
              {preview.errors.length > 0 && (
                <div className="text-destructive text-[11px] space-y-0.5">
                  {preview.errors.slice(0, 5).map((e, i) => (
                    <div key={i}>{e}</div>
                  ))}
                </div>
              )}
            </div>
          )}
        </div>
        <DialogFooter>
          <Button variant="outline" onClick={onClose}>
            Cancel
          </Button>
          <Button onClick={submit} disabled={saving || preview.rows.length === 0}>
            {saving && <Loader2 className="h-4 w-4 mr-2 animate-spin" />}
            Import {preview.rows.length || ""}
          </Button>
        </DialogFooter>
      </DialogContent>
    </Dialog>
  );
}