import type { ReactNode } from "react";
import { Badge, Box, Collapse, Group, Stack, Text, UnstyledButton } from "@mantine/core";
import type { LucideIcon } from "lucide-react";
import { Check, ChevronDown, Lock } from "lucide-react";

import { freightBrand } from "@/theme/freight-brand";

export type WorkflowStepState = "complete" | "active" | "upcoming";

/**
 * A single collapsible step in the scheduling workflow. Steps are stacked
 * inside <WorkflowRail> which paints the continuous connector behind the
 * status circles.
 */
export function WorkflowStep({
  index,
  icon: Icon,
  title,
  subtitle,
  state,
  open,
  onToggle,
  rightSlot,
  locked = false,
  children,
}: {
  index: number;
  icon: LucideIcon;
  title: string;
  subtitle?: string;
  state: WorkflowStepState;
  open: boolean;
  onToggle: () => void;
  rightSlot?: ReactNode;
  locked?: boolean;
  children: ReactNode;
}) {
  const isComplete = state === "complete";
  const isActive = state === "active";

  const circle = (() => {
    if (isComplete) {
      return {
        bg: freightBrand.primary,
        color: "white",
        border: freightBrand.primary,
        shadow: `0 4px 10px ${freightBrand.ring}`,
      };
    }
    if (isActive) {
      return {
        bg: "white",
        color: freightBrand.primary,
        border: freightBrand.primary,
        shadow: `0 0 0 4px ${freightBrand.ring}`,
      };
    }
    return {
      bg: "var(--mantine-color-gray-1)",
      color: "var(--mantine-color-gray-5)",
      border: "var(--mantine-color-gray-3)",
      shadow: "none",
    };
  })();

  return (
    <Group gap="md" align="stretch" wrap="nowrap">
      {/* Status circle (sits above the rail) */}
      <Box
        style={{
          width: 40,
          flexShrink: 0,
          display: "flex",
          justifyContent: "center",
        }}
      >
        <Box
          style={{
            width: 40,
            height: 40,
            borderRadius: "50%",
            display: "flex",
            alignItems: "center",
            justifyContent: "center",
            background: circle.bg,
            color: circle.color,
            border: `2px solid ${circle.border}`,
            boxShadow: circle.shadow,
            fontWeight: 700,
            fontSize: 15,
            transition: "all 150ms ease",
            position: "relative",
            zIndex: 1,
          }}
        >
          {isComplete ? <Check size={20} /> : <Icon size={18} />}
        </Box>
      </Box>

      {/* Step card */}
      <Box
        style={{
          flex: 1,
          minWidth: 0,
          marginBottom: 4,
          borderRadius: 16,
          border: `1px solid ${
            isActive ? freightBrand.mutedBorder : "var(--mantine-color-gray-2)"
          }`,
          background: isActive ? freightBrand.mutedBg : "white",
          boxShadow: isActive ? `0 6px 20px ${freightBrand.ring}` : "none",
          overflow: "hidden",
          transition: "all 150ms ease",
        }}
      >
        <UnstyledButton
          onClick={onToggle}
          style={{ display: "block", width: "100%", padding: "14px 18px" }}
        >
          <Group justify="space-between" wrap="nowrap" gap="sm">
            <Stack gap={2} style={{ minWidth: 0 }}>
              <Group gap={8} wrap="nowrap">
                <Text
                  size="xs"
                  fw={700}
                  c={isComplete || isActive ? "green.7" : "dimmed"}
                  style={{ letterSpacing: 0.6 }}
                >
                  STEP {index + 1}
                </Text>
                {isComplete ? (
                  <Badge size="xs" variant="light" color="green" radius="sm">
                    Done
                  </Badge>
                ) : null}
              </Group>
              <Text fw={700} size="md" lh={1.2} truncate>
                {title}
              </Text>
              {subtitle ? (
                <Text size="xs" c="dimmed" truncate>
                  {subtitle}
                </Text>
              ) : null}
            </Stack>

            <Group gap="sm" wrap="nowrap" style={{ flexShrink: 0 }}>
              {rightSlot}
              <Box
                style={{
                  display: "flex",
                  alignItems: "center",
                  justifyContent: "center",
                  width: 28,
                  height: 28,
                  borderRadius: 8,
                  background: open
                    ? "var(--mantine-color-green-0)"
                    : "var(--mantine-color-gray-1)",
                  color: open
                    ? "var(--mantine-color-green-7)"
                    : "var(--mantine-color-gray-6)",
                }}
              >
                {locked ? (
                  <Lock size={14} />
                ) : (
                  <ChevronDown
                    size={16}
                    style={{
                      transform: open ? "rotate(180deg)" : "none",
                      transition: "transform 150ms ease",
                    }}
                  />
                )}
              </Box>
            </Group>
          </Group>
        </UnstyledButton>

        <Collapse expanded={open}>
          <Box
            px="lg"
            pb="lg"
            pt={4}
            style={{ borderTop: "1px solid var(--mantine-color-gray-1)" }}
          >
            <Box pt="md">{children}</Box>
          </Box>
        </Collapse>
      </Box>
    </Group>
  );
}

/**
 * Wraps a list of <WorkflowStep> and paints the continuous vertical rail that
 * connects the status circles.
 */
export function WorkflowRail({ children }: { children: ReactNode }) {
  return (
    <Box style={{ position: "relative" }}>
      {/* connector rail behind the circles (circle is 40px → center at 20) */}
      <Box
        style={{
          position: "absolute",
          left: 19,
          top: 24,
          bottom: 24,
          width: 2,
          background:
            "linear-gradient(180deg, var(--mantine-color-green-3) 0%, var(--mantine-color-gray-3) 100%)",
          borderRadius: 2,
          pointerEvents: "none",
        }}
      />
      <Stack gap="md">{children}</Stack>
    </Box>
  );
}