"use client";

import { useState } from "react";
import type { FieldConfig, FieldHistoryEntry, SelectOption } from "@/types/form";

const currencyFmt = new Intl.NumberFormat("en-US", {
  style: "currency",
  currency: "USD",
  maximumFractionDigits: 2,
});

const numberFmt = new Intl.NumberFormat("en-US");

export function FormattedValue({
  value,
  field,
  options,
}: {
  value: unknown;
  field: FieldConfig;
  options: Record<number, SelectOption[]>;
}) {
  if (value === null || value === undefined || value === "") return <>—</>;

  const opts: SelectOption[] | undefined = field.optionGroupId
    ? options[field.optionGroupId]
    : field.options;

  switch (field.type) {
    case "currency": {
      const n = typeof value === "number" ? value : Number(value);
      return <>{Number.isFinite(n) ? currencyFmt.format(n) : String(value)}</>;
    }
    case "percent": {
      const n = typeof value === "number" ? value : Number(value);
      return <>{Number.isFinite(n) ? `${n}%` : String(value)}</>;
    }
    case "number": {
      const n = typeof value === "number" ? value : Number(value);
      return <>{Number.isFinite(n) ? numberFmt.format(n) : String(value)}</>;
    }
    case "date":
      return <>{formatLongDate(String(value))}</>;
    case "boolean":
      return <>{value ? "Yes" : "No"}</>;
    case "select":
    case "readonly": {
      const v = String(value);
      const found = opts?.find((o) => o.value === v);
      return <>{found?.label ?? v}</>;
    }
    case "multiselect": {
      let parts: string[];
      if (Array.isArray(value)) {
        parts = value.map(String);
      } else {
        parts = String(value).split(/[|,]/).map((s) => s.trim()).filter(Boolean);
      }
      const labels = parts.map((p) => opts?.find((o) => o.value === p)?.label ?? p);
      return <>{labels.join(", ")}</>;
    }
    case "file": {
      // Prefill / history wraps file values into { id, file_name } so the
      // UI can show a human-readable name. Fall back to whatever scalar
      // came through if the shape is different.
      if (typeof value === "object" && value !== null) {
        const o = value as Record<string, unknown>;
        const fname = o.file_name ?? o.name ?? o.label ?? o.filename;
        if (typeof fname === "string" && fname.length > 0) return <>{fname}</>;
        if (typeof o.id !== "undefined") return <>Attachment #{String(o.id)}</>;
      }
      return <>{String(value)}</>;
    }
    case "textarea":
    case "text":
    case "email":
    case "phone":
    default:
      return <>{String(value)}</>;
  }
}

export function formatShortDate(iso: string): string {
  if (!iso) return "—";
  const d = new Date(iso);
  if (Number.isNaN(d.getTime())) return iso;
  return d.toLocaleDateString("en-US", { month: "short", day: "numeric", year: "numeric" });
}

export function formatLongDate(iso: string): string {
  if (!iso) return "—";
  const m = /^(\d{4})-(\d{2})-(\d{2})$/.exec(iso);
  const d = m
    ? new Date(Number(m[1]), Number(m[2]) - 1, Number(m[3]))
    : new Date(iso);
  if (Number.isNaN(d.getTime())) return iso;
  return d.toLocaleDateString("en-US", { month: "long", day: "numeric", year: "numeric" });
}

export function computeDateRange(dates: string[]): { from: string; to: string } | null {
  if (dates.length === 0) return null;
  const times = dates
    .map((d) => new Date(d).getTime())
    .filter((t) => Number.isFinite(t));
  if (times.length === 0) return null;
  const min = new Date(Math.min(...times)).toISOString();
  const max = new Date(Math.max(...times)).toISOString();
  return { from: min, to: max };
}

export function Chevron({ open }: { open: boolean }) {
  return (
    <svg
      aria-hidden
      viewBox="0 0 20 20"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.5"
      strokeLinecap="round"
      className={"h-5 w-5 flex-shrink-0 text-ink-mute transition-transform duration-300 " + (open ? "rotate-180" : "")}
    >
      <path d="M5 8 L10 13 L15 8" />
    </svg>
  );
}

export function FieldHistoryRow({
  field,
  entries,
  options,
}: {
  field: FieldConfig;
  entries: FieldHistoryEntry[];
  options: Record<number, SelectOption[]>;
}) {
  const [expanded, setExpanded] = useState(false);
  const latest = entries[0];
  const priorEntries = entries.slice(1);

  return (
    <div className="px-5 py-4 sm:px-7">
      <div className="flex flex-col gap-1.5 sm:flex-row sm:items-baseline sm:justify-between sm:gap-6">
        <div className="min-w-0 sm:max-w-[16rem]">
          <p className="text-sm font-medium text-ink">{field.label}</p>
          {field.help && (
            <p className="mt-0.5 text-xs leading-relaxed text-ink-mute">{field.help}</p>
          )}
        </div>
        <div className="flex-1 min-w-0 text-left sm:text-right">
          <p className="font-display text-lg font-medium leading-snug text-leaf-800 tabular-nums">
            <FormattedValue value={latest.value} field={field} options={options} />
          </p>
          <p className="mt-0.5 text-[11px] uppercase tracking-[0.1em] text-ink-mute">
            as of {formatShortDate(latest.date)}
            {priorEntries.length > 0 && (
              <>
                {" · "}
                <button
                  type="button"
                  onClick={() => setExpanded((v) => !v)}
                  aria-expanded={expanded}
                  className="font-medium normal-case tracking-normal text-leaf-700 hover:text-leaf-800 hover:underline focus:outline-none focus-visible:underline"
                >
                  {expanded ? "Hide" : `${priorEntries.length} earlier ${priorEntries.length === 1 ? "entry" : "entries"}`}
                </button>
              </>
            )}
          </p>
        </div>
      </div>

      {expanded && priorEntries.length > 0 && (
        <ol className="mt-3 space-y-1.5 border-l-2 border-rule-soft pl-4 sm:ml-auto sm:max-w-[24rem]">
          {priorEntries.map((e) => (
            <li
              key={e.activityId}
              className="flex items-baseline justify-between gap-4 text-sm"
            >
              <span className="text-[11px] uppercase tracking-[0.1em] text-ink-mute tabular-nums">
                {formatShortDate(e.date)}
              </span>
              <span className="text-right text-ink-soft tabular-nums">
                <FormattedValue value={e.value} field={field} options={options} />
              </span>
            </li>
          ))}
        </ol>
      )}
    </div>
  );
}

export function FieldHistoryGroup({
  label,
  fields,
  history,
  options,
}: {
  label?: string;
  fields: FieldConfig[];
  history: Record<string, FieldHistoryEntry[]>;
  options: Record<number, SelectOption[]>;
}) {
  return (
    <div className="border-l-2 border-leaf-300/60">
      {label && (
        <p className="px-5 pt-3 pb-1 pl-7 text-[10px] uppercase tracking-[0.1em] font-medium text-ink-soft sm:px-7 sm:pl-9">
          {label}
        </p>
      )}
      <div className="divide-y divide-rule-soft">
        {fields.map((f) => (
          <FieldHistoryRow
            key={f.name}
            field={f}
            entries={history[f.name] ?? []}
            options={options}
          />
        ))}
      </div>
    </div>
  );
}

export { currencyFmt, numberFmt };