import type { CardAct, CardBlock, CardSection } from "@rakazo/contracts";
import { CARD_LIMITS } from "@rakazo/contracts";
import {
  applyCardAct,
  cardScale,
  cardTimerRemaining,
  checklistItemDisplay,
  formatCardClock,
  formatCardTimerLength,
  suggestionStatus,
} from "@rakazo/core";
import { useState } from "react";
import { Alert, Pressable, StyleSheet, Text, View } from "react-native";
import { mobileTokens } from "../lib/appearance";
import { dateLocaleForUi, useI18n } from "../lib/i18n";
import { CookingMode, useNow } from "./cooking-mode";
import { NativeSymbol } from "./native-symbol";

type Section<T extends CardSection["type"]> = Extract<CardSection, { type: T }>;

/** A bot's interactive card. Taps go to the server, which owns the card's state. */
export function ThreadCard({
  block: stored,
  createdAt,
  onAct,
}: {
  block: CardBlock;
  /** When the card was posted; an open suggestion expires after a while. */
  createdAt?: string;
  onAct?: (act: CardAct) => Promise<void>;
}) {
  const tokens = mobileTokens();
  const { t, locale } = useI18n();
  const [pending, setPending] = useState<CardAct | null>(null);
  const [expanded, setExpanded] = useState<string[]>([]);
  const [cooking, setCooking] = useState(false);
  // Show the tap in flight on top of the stored card, so the card answers at once.
  const preview = pending ? applyCardAct(stored, pending) : null;
  const block = preview?.ok ? preview.block : stored;
  const suggestion = block.suggestion
    ? suggestionStatus(block, createdAt ?? new Date())
    : undefined;
  // A suggestion takes one tap; once it moved on, only its outcome shows.
  const answered = Boolean(block.answer) || (suggestion !== undefined && suggestion !== "proposed");
  const busy = !onAct || pending !== null;
  const factor = cardScale(block);
  const header = block.sections?.find((part): part is Section<"header"> => part.type === "header");
  const steps = block.sections?.find((part): part is Section<"steps"> => part.type === "steps");
  const now = useNow(Boolean(steps?.steps.some((step) => step.timerEndsAt)));

  async function act(next: CardAct) {
    if (!onAct || pending) return;
    setPending(next);
    try {
      await onAct(next);
    } catch (error) {
      Alert.alert(
        t("Could not submit answer"),
        error instanceof Error ? error.message : t("Please try again."),
      );
    } finally {
      setPending(null);
    }
  }

  function visible<T>(id: string, entries: T[]): { shown: T[]; hidden: number } {
    if (expanded.includes(id) || entries.length <= CARD_LIMITS.collapsedEntries + 1) {
      return { shown: entries, hidden: 0 };
    }
    return {
      shown: entries.slice(0, CARD_LIMITS.collapsedEntries),
      hidden: entries.length - CARD_LIMITS.collapsedEntries,
    };
  }

  function showMore(id: string, hidden: number) {
    if (!hidden) return null;
    return (
      <Pressable
        accessibilityRole="button"
        onPress={() => setExpanded((ids) => [...ids, id])}
        style={{ paddingVertical: 6 }}
      >
        <Text style={[styles.small, { color: tokens.mutedForeground }]}>
          {t("Show {count} more", { count: hidden })}
        </Text>
      </Pressable>
    );
  }

  const roundButton = (
    label: string,
    symbol: { ios: string; android: "remove" | "add" },
    disabled: boolean,
    onPress: () => void,
  ) => (
    <Pressable
      accessibilityRole="button"
      accessibilityLabel={label}
      accessibilityState={{ disabled }}
      disabled={disabled}
      onPress={onPress}
      style={[styles.round, { borderColor: tokens.border, opacity: disabled ? 0.4 : 1 }]}
    >
      <NativeSymbol ios={symbol.ios} android={symbol.android} size={16} />
    </Pressable>
  );
  const select = block.sections?.find((part): part is Section<"select"> => part.type === "select");
  const nothingChosen = Boolean(select?.multiple && !select.selected?.length);

  return (
    <View
      testID="thread-card"
      style={[styles.card, { borderColor: tokens.border, backgroundColor: tokens.card }]}
    >
      {block.sections?.map((part, index) => {
        if (part.type === "header") {
          return (
            <View key={index} style={{ gap: 2 }}>
              <Text style={[styles.title, { color: tokens.foreground }]}>{part.title}</Text>
              {part.subtitle ? (
                <Text style={[styles.small, { color: tokens.mutedForeground }]}>
                  {part.subtitle}
                </Text>
              ) : null}
              {part.meta?.length ? (
                <Text style={[styles.small, { color: tokens.mutedForeground }]}>
                  {part.meta.join(" · ")}
                </Text>
              ) : null}
            </View>
          );
        }
        if (part.type === "facts") {
          return (
            <View key={index} style={{ gap: 6 }}>
              {part.rows.map((row) => (
                <View key={row.label} style={styles.factRow}>
                  <Text style={[styles.body, { color: tokens.mutedForeground }]}>{row.label}</Text>
                  <Text style={[styles.body, styles.factValue, { color: tokens.foreground }]}>
                    {row.value}
                  </Text>
                </View>
              ))}
            </View>
          );
        }
        if (part.type === "stepper") {
          const label = part.label;
          return (
            <View key={index} style={styles.stepperRow}>
              <Text style={[styles.body, { color: tokens.mutedForeground }]}>{label}</Text>
              <View style={styles.stepperControls}>
                {roundButton(
                  t("Fewer {label}", { label }),
                  { ios: "minus", android: "remove" },
                  busy || part.value <= 1,
                  () => void act({ type: "stepper", sectionId: part.id, value: part.value - 1 }),
                )}
                <Text
                  testID="card-stepper-value"
                  style={[styles.body, styles.stepperValue, { color: tokens.foreground }]}
                >
                  {part.value}
                </Text>
                {roundButton(
                  t("More {label}", { label }),
                  { ios: "plus", android: "add" },
                  busy || part.value >= CARD_LIMITS.stepperMax,
                  () => void act({ type: "stepper", sectionId: part.id, value: part.value + 1 }),
                )}
              </View>
            </View>
          );
        }
        if (part.type === "steps") {
          const { shown, hidden } = visible(part.id, part.steps);
          return (
            <View key={index} style={{ gap: 10 }}>
              {shown.map((step, position) => {
                const remaining = cardTimerRemaining(step.timerEndsAt, now);
                return (
                  <View key={step.id} style={{ flexDirection: "row", gap: 10 }}>
                    <Text
                      style={[styles.body, styles.stepNumber, { color: tokens.mutedForeground }]}
                    >
                      {position + 1}
                    </Text>
                    <View style={{ flex: 1, gap: 2 }}>
                      <Text style={[styles.body, { color: tokens.foreground }]}>{step.text}</Text>
                      {step.timerSeconds ? (
                        <Text style={[styles.small, { color: tokens.mutedForeground }]}>
                          {remaining !== null
                            ? formatCardClock(remaining)
                            : formatCardTimerLength(step.timerSeconds, dateLocaleForUi(locale))}
                        </Text>
                      ) : null}
                    </View>
                  </View>
                );
              })}
              {showMore(part.id, hidden)}
            </View>
          );
        }
        if (part.type === "checklist") {
          const { shown, hidden } = visible(part.id, part.items);
          return (
            <View key={index}>
              {shown.map((item) => {
                const checked = Boolean(item.checked);
                const display = checklistItemDisplay(item, factor);
                return (
                  <Pressable
                    key={item.id}
                    accessibilityRole="checkbox"
                    accessibilityState={{ checked, disabled: busy }}
                    disabled={busy}
                    onPress={() =>
                      void act({
                        type: "toggle",
                        sectionId: part.id,
                        itemId: item.id,
                        checked: !checked,
                      })
                    }
                    style={styles.checkRow}
                  >
                    <NativeSymbol
                      ios={checked ? "checkmark.circle.fill" : "circle"}
                      android={checked ? "checkmark-circle" : "ellipse-outline"}
                      size={20}
                      color={checked ? tokens.primary : tokens.mutedForeground}
                    />
                    <Text
                      style={[
                        styles.body,
                        {
                          flexShrink: 1,
                          color: checked ? tokens.mutedForeground : tokens.foreground,
                        },
                        checked && { textDecorationLine: "line-through" },
                      ]}
                    >
                      {display.amount ? (
                        <Text style={{ fontWeight: "600" }}>{display.amount} </Text>
                      ) : null}
                      {display.label}
                    </Text>
                  </Pressable>
                );
              })}
              {showMore(part.id, hidden)}
            </View>
          );
        }
        if (part.type === "select") {
          return (
            <View key={index} style={part.multiple ? styles.chips : { gap: 6 }}>
              {part.options.map((option) => {
                const chosen = part.selected?.includes(option.id) ?? false;
                return (
                  <Pressable
                    key={option.id}
                    accessibilityRole="button"
                    accessibilityState={{ selected: chosen, disabled: busy || answered }}
                    disabled={busy || answered}
                    onPress={() =>
                      void act({
                        type: "select",
                        sectionId: part.id,
                        optionId: option.id,
                        ...(part.multiple ? { selected: !chosen } : {}),
                      })
                    }
                    style={[
                      styles.option,
                      part.multiple ? null : { alignSelf: "stretch" },
                      {
                        borderColor: chosen ? tokens.primary : tokens.border,
                        backgroundColor: chosen ? tokens.primary : "transparent",
                        opacity: answered && !chosen ? 0.5 : 1,
                      },
                    ]}
                  >
                    <Text
                      style={[
                        styles.body,
                        { color: chosen ? tokens.primaryForeground : tokens.foreground },
                      ]}
                    >
                      {option.label}
                    </Text>
                  </Pressable>
                );
              })}
            </View>
          );
        }
        const actions = part.actions.filter((action) => action.kind === "steps" || !answered);
        if (!actions.length) return null;
        return (
          <View key={index} style={styles.chips}>
            {actions.map((action, position) => {
              const primary = position === 0;
              const opensSteps = action.kind === "steps";
              const disabled = opensSteps ? !steps : busy || nothingChosen;
              return (
                <Pressable
                  key={action.id}
                  accessibilityRole="button"
                  accessibilityState={{ disabled }}
                  disabled={disabled}
                  onPress={() =>
                    opensSteps
                      ? setCooking(true)
                      : void act({ type: "action", actionId: action.id })
                  }
                  style={[
                    styles.option,
                    {
                      borderColor: primary ? tokens.primary : tokens.border,
                      backgroundColor: primary ? tokens.primary : "transparent",
                      opacity: disabled ? 0.5 : 1,
                    },
                  ]}
                >
                  <Text
                    style={[
                      styles.body,
                      {
                        fontWeight: "600",
                        color: primary ? tokens.primaryForeground : tokens.foreground,
                      },
                    ]}
                  >
                    {action.kind === "accept"
                      ? t("Accept")
                      : action.kind === "dismiss"
                        ? t("Dismiss")
                        : action.label}
                  </Text>
                </Pressable>
              );
            })}
          </View>
        );
      })}
      {suggestion && suggestion !== "proposed" ? (
        <Text
          style={[
            styles.small,
            {
              color:
                suggestion === "failed"
                  ? tokens.destructive
                  : suggestion === "done"
                    ? tokens.success
                    : tokens.mutedForeground,
            },
          ]}
        >
          {suggestion === "failed"
            ? (block.suggestion?.error ?? t("Failed"))
            : suggestion === "running"
              ? t("Running")
              : suggestion === "done"
                ? t("Done")
                : suggestion === "dismissed"
                  ? t("Dismissed")
                  : t("Expired")}
        </Text>
      ) : null}
      {cooking && steps ? (
        <CookingMode
          title={header?.title ?? ""}
          steps={steps}
          now={now}
          busy={busy}
          onAct={act}
          onClose={() => setCooking(false)}
        />
      ) : null}
    </View>
  );
}

const styles = StyleSheet.create({
  card: {
    width: "90%",
    gap: 14,
    borderRadius: 18,
    borderWidth: 1,
    paddingHorizontal: 16,
    paddingVertical: 14,
  },
  title: { fontSize: 16, fontWeight: "600" },
  body: { fontSize: 15.5, lineHeight: 22 },
  small: { fontSize: 13.5 },
  factRow: { flexDirection: "row", gap: 12 },
  factValue: { flex: 1 },
  checkRow: { flexDirection: "row", alignItems: "center", gap: 10, paddingVertical: 6 },
  chips: { flexDirection: "row", flexWrap: "wrap", gap: 6 },
  option: { borderRadius: 12, borderWidth: 1, paddingHorizontal: 14, paddingVertical: 10 },
  stepperRow: { flexDirection: "row", alignItems: "center", justifyContent: "space-between" },
  stepperControls: { flexDirection: "row", alignItems: "center", gap: 8 },
  stepperValue: { minWidth: 28, textAlign: "center", fontWeight: "600" },
  round: {
    width: 34,
    height: 34,
    borderRadius: 17,
    borderWidth: 1,
    alignItems: "center",
    justifyContent: "center",
  },
  stepNumber: { width: 16, textAlign: "right" },
});