"use client";

import { useState } from "react";
import { clsx } from "clsx";
import { InfoTooltip } from "~/components/ui/InfoTooltip.js";
import { formatCents } from "~/lib/format.js";
import { trpc } from "~/lib/trpc/client.js";

interface ApplyExperienceMultipliersProps {
  estimateId: string;
  canEdit: boolean;
  onApplied?: () => void;
}

export function ApplyExperienceMultipliers({ estimateId, canEdit, onApplied }: ApplyExperienceMultipliersProps) {
  const utils = trpc.useUtils();
  const { data: sets, isLoading } = trpc.experienceMultiplier.list.useQuery();

  const [selectedSetId, setSelectedSetId] = useState<string>("");
  const [showPreview, setShowPreview] = useState(false);

  const previewQuery = trpc.experienceMultiplier.preview.useQuery(
    { estimateId, multiplierSetId: selectedSetId },
    { enabled: showPreview && Boolean(selectedSetId) },
  );

  const applyMutation = trpc.experienceMultiplier.applyRules.useMutation({
    onSuccess: (result) => {
      utils.estimate.getById.invalidate();
      setShowPreview(false);
      onApplied?.();
      alert(
        `Updated ${result.linesUpdated} demand line(s).\n` +
          `Hours: ${result.totalOriginalHours}h -> ${result.totalAdjustedHours}h`,
      );
    },
  });

  // Auto-select default set
  if (!selectedSetId && sets) {
    const defaultSet = sets.find((s) => s.isDefault) ?? sets[0];
    if (defaultSet) {
      setSelectedSetId(defaultSet.id);
    }
  }

  if (!canEdit) return null;

  if (isLoading) {
    return <p className="text-sm text-gray-400">Loading experience multipliers...</p>;
  }

  if (!sets || sets.length === 0) {
    return (
      <div className="rounded-2xl border border-dashed border-gray-300 bg-gray-50 p-4 text-center text-sm text-gray-500">
        No experience multiplier sets defined.{" "}
        <a href="/admin/experience-multipliers" className="text-brand-600 hover:underline">
          Create one
        </a>{" "}
        to apply rate and effort adjustments.
      </div>
    );
  }

  return (
    <div className="rounded-3xl border border-gray-200 bg-white p-5 shadow-sm">
      <h3 className="mb-3 text-base font-semibold text-gray-900">Apply experience multipliers <InfoTooltip content="Experience multipliers adjust hours, cost rates, and bill rates based on rules like seniority level or chapter. A multiplier >1 increases effort, <1 decreases it." /></h3>

      <div className="flex flex-wrap items-end gap-4">
        <label className="block">
          <span className="mb-1 block text-xs font-medium text-gray-500 uppercase tracking-wider">Multiplier set <InfoTooltip content="Select which set of rules to apply. Each set contains rules that match by chapter, role, or level." /></span>
          <select
            value={selectedSetId}
            onChange={(e) => {
              setSelectedSetId(e.target.value);
              setShowPreview(false);
            }}
            className="rounded-2xl border border-gray-300 bg-gray-50 px-3 py-2 text-sm text-gray-900"
          >
            {sets.map((s) => (
              <option key={s.id} value={s.id}>
                {s.name} ({s.rules.length} rules){s.isDefault ? " *" : ""}
              </option>
            ))}
          </select>
        </label>

        <button
          onClick={() => setShowPreview(!showPreview)}
          disabled={!selectedSetId}
          className="rounded-2xl border border-gray-300 px-4 py-2 text-sm font-medium text-gray-600 hover:bg-gray-50 disabled:opacity-50"
        >
          {showPreview ? "Hide preview" : "Preview"}
        </button>

        <button
          onClick={() => {
            if (!selectedSetId) return;
            if (confirm("This will update cost/bill rates and hours on matching demand lines. Continue?")) {
              applyMutation.mutate({ estimateId, multiplierSetId: selectedSetId });
            }
          }}
          disabled={!selectedSetId || applyMutation.isPending}
          className="rounded-2xl bg-brand-600 px-4 py-2 text-sm font-medium text-white hover:bg-brand-700 disabled:opacity-50"
        >
          {applyMutation.isPending ? "Applying..." : "Apply multipliers"}
        </button>
      </div>

      {applyMutation.error && (
        <p className="mt-2 text-sm text-red-600">{applyMutation.error.message}</p>
      )}

      {/* Preview */}
      {showPreview && previewQuery.data && (
        <div className="mt-4 space-y-3">
          <div className="flex flex-wrap gap-4 text-sm text-gray-600">
            <span>{previewQuery.data.demandLineCount} demand lines</span>
            <span>{previewQuery.data.ruleCount} rules</span>
            <span className="font-semibold text-brand-700">
              {previewQuery.data.linesChanged} line(s) would be adjusted
            </span>
          </div>

          {previewQuery.data.linesChanged > 0 && (
            <div className="rounded-xl bg-blue-50 p-3 text-sm text-blue-700">
              Total cost: {formatCents(previewQuery.data.totalOriginalCostCents)} {"->"}{" "}
              {formatCents(previewQuery.data.totalAdjustedCostCents)}
            </div>
          )}

          {/* Per-line preview */}
          {previewQuery.data.previews.length > 0 && (
            <details className="text-sm">
              <summary className="cursor-pointer text-gray-500 hover:text-gray-700">
                Show all {previewQuery.data.previews.length} lines
              </summary>
              <div className="mt-2 overflow-x-auto">
                <table className="w-full text-left text-sm">
                  <thead>
                    <tr className="border-b border-gray-200 text-xs uppercase tracking-wider text-gray-500">
                      <th className="py-2 pr-3 font-medium">Name</th>
                      <th className="px-3 py-2 font-medium">Chapter</th>
                      <th className="px-3 py-2 text-right font-medium">Cost rate</th>
                      <th className="px-3 py-2 text-right font-medium">Bill rate</th>
                      <th className="px-3 py-2 text-right font-medium">Hours</th>
                      <th className="pl-3 py-2 font-medium">Changes</th>
                    </tr>
                  </thead>
                  <tbody>
                    {previewQuery.data.previews.map((p, i) => (
                      <tr
                        key={p.demandLineId}
                        className={clsx(
                          "border-b border-gray-100",
                          p.hasChanges ? "bg-amber-50" : i % 2 === 0 ? "" : "bg-gray-50",
                        )}
                      >
                        <td className="py-1.5 pr-3 text-gray-900">{p.name}</td>
                        <td className="px-3 py-1.5 text-gray-500">{p.chapter ?? "\u2014"}</td>
                        <td className="px-3 py-1.5 text-right tabular-nums text-gray-700">
                          {p.hasChanges && p.adjustedCostRateCents !== p.originalCostRateCents ? (
                            <>
                              <span className="line-through text-gray-400">{formatCents(p.originalCostRateCents)}</span>{" "}
                              {formatCents(p.adjustedCostRateCents)}
                            </>
                          ) : (
                            formatCents(p.originalCostRateCents)
                          )}
                        </td>
                        <td className="px-3 py-1.5 text-right tabular-nums text-gray-700">
                          {p.hasChanges && p.adjustedBillRateCents !== p.originalBillRateCents ? (
                            <>
                              <span className="line-through text-gray-400">{formatCents(p.originalBillRateCents)}</span>{" "}
                              {formatCents(p.adjustedBillRateCents)}
                            </>
                          ) : (
                            formatCents(p.originalBillRateCents)
                          )}
                        </td>
                        <td className="px-3 py-1.5 text-right tabular-nums text-gray-700">
                          {p.hasChanges && p.adjustedHours !== p.originalHours ? (
                            <>
                              <span className="line-through text-gray-400">{p.originalHours}h</span>{" "}
                              {p.adjustedHours}h
                            </>
                          ) : (
                            `${p.originalHours}h`
                          )}
                        </td>
                        <td className="pl-3 py-1.5 text-xs text-gray-500">
                          {p.hasChanges ? p.appliedRules[0] ?? "" : "No change"}
                        </td>
                      </tr>
                    ))}
                  </tbody>
                </table>
              </div>
            </details>
          )}
        </div>
      )}

      {showPreview && previewQuery.isLoading && (
        <p className="mt-3 text-sm text-gray-400">Computing preview...</p>
      )}
    </div>
  );
}
