import { useState } from "react";
import {
  Badge,
  Box,
  Button,
  Group,
  Stack,
  Text,
  Textarea,
  ThemeIcon,
} from "@mantine/core";
import { Check, Circle, Clock, MinusCircle } from "lucide-react";
import type { Freight } from "@edr/types";

export interface ClearanceMilestoneTimelineProps {
  milestones: Freight.IClearanceMilestone[];
  /** Complete a milestone by code (omit to render read-only). */
  onComplete?: (code: string, note?: string) => void;
  /** True while a complete mutation is in flight. */
  busy?: boolean;
}

const STATUS_META: Record<
  Freight.MilestoneStatus,
  { color: string; label: string }
> = {
  COMPLETED: { color: "edr-green", label: "Completed" },
  PENDING: { color: "gray", label: "Pending" },
  SKIPPED: { color: "gray", label: "Skipped" },
};

/** Vertical timeline of GL clearance milestones with inline complete actions. */
export function ClearanceMilestoneTimeline({
  milestones,
  onComplete,
  busy,
}: ClearanceMilestoneTimelineProps) {
  const [openNote, setOpenNote] = useState<Record<string, boolean>>({});
  const [notes, setNotes] = useState<Record<string, string>>({});

  const sorted = [...milestones].sort((a, b) => a.sortOrder - b.sortOrder);
  const nextPending = sorted.find((m) => m.status === "PENDING");

  if (sorted.length === 0) {
    return (
      <Text size="sm" c="dimmed">
        No milestones for this shipment yet.
      </Text>
    );
  }

  return (
    <Stack gap={0}>
      {sorted.map((m, index) => {
        const isLast = index === sorted.length - 1;
        const meta = STATUS_META[m.status];
        const isNext = nextPending?.id === m.id;
        const Icon =
          m.status === "COMPLETED"
            ? Check
            : m.status === "SKIPPED"
              ? MinusCircle
              : isNext
                ? Clock
                : Circle;

        return (
          <Group key={m.id} gap="sm" wrap="nowrap" align="flex-start">
            <Stack gap={0} align="center" style={{ flexShrink: 0 }}>
              <ThemeIcon
                variant={m.status === "COMPLETED" ? "filled" : "light"}
                color={isNext ? "edr-green" : meta.color}
                radius="xl"
                size={30}
              >
                <Icon size={15} strokeWidth={2.2} />
              </ThemeIcon>
              {!isLast && (
                <Box
                  style={{
                    width: 2,
                    flex: 1,
                    minHeight: 28,
                    background:
                      m.status === "COMPLETED"
                        ? "var(--mantine-color-edr-green-4)"
                        : "var(--mantine-color-gray-2)",
                  }}
                />
              )}
            </Stack>

            <Box pb={isLast ? 0 : "md"} style={{ flex: 1, minWidth: 0 }}>
              <Group justify="space-between" wrap="nowrap" align="flex-start">
                <Box style={{ minWidth: 0 }}>
                  <Text size="sm" fw={600} truncate>
                    {m.milestoneLabel}
                  </Text>
                  <Group gap={6} mt={2} wrap="nowrap">
                    <Badge size="xs" variant="light" color={meta.color}>
                      {meta.label}
                    </Badge>
                    {m.ownerRegion ? (
                      <Badge size="xs" variant="default">
                        {m.ownerRegion}
                      </Badge>
                    ) : null}
                  </Group>
                  {m.note ? (
                    <Text size="xs" c="dimmed" mt={4}>
                      {m.note}
                    </Text>
                  ) : null}
                </Box>

                {onComplete && m.status === "PENDING" && isNext ? (
                  !openNote[m.milestoneCode] ? (
                    <Button
                      size="compact-xs"
                      color="edr-green"
                      leftSection={<Check size={13} />}
                      disabled={busy}
                      onClick={() =>
                        setOpenNote((o) => ({
                          ...o,
                          [m.milestoneCode]: true,
                        }))
                      }
                    >
                      Complete
                    </Button>
                  ) : null
                ) : null}
              </Group>

              {onComplete && openNote[m.milestoneCode] && (
                <Box mt="xs">
                  <Textarea
                    placeholder="Optional note for this milestone…"
                    value={notes[m.milestoneCode] ?? ""}
                    onChange={(e) =>
                      setNotes((n) => ({
                        ...n,
                        [m.milestoneCode]: e.currentTarget.value,
                      }))
                    }
                    autosize
                    minRows={2}
                    size="sm"
                    radius="md"
                  />
                  <Group justify="flex-end" gap={8} mt={8}>
                    <Button
                      size="compact-xs"
                      variant="subtle"
                      color="gray"
                      disabled={busy}
                      onClick={() =>
                        setOpenNote((o) => ({
                          ...o,
                          [m.milestoneCode]: false,
                        }))
                      }
                    >
                      Cancel
                    </Button>
                    <Button
                      size="compact-xs"
                      color="edr-green"
                      leftSection={<Check size={13} />}
                      loading={busy}
                      onClick={() => {
                        onComplete(
                          m.milestoneCode,
                          notes[m.milestoneCode]?.trim() || undefined,
                        );
                        setOpenNote((o) => ({
                          ...o,
                          [m.milestoneCode]: false,
                        }));
                      }}
                    >
                      Mark complete
                    </Button>
                  </Group>
                </Box>
              )}
            </Box>
          </Group>
        );
      })}
    </Stack>
  );
}