import { useState } from "react";
import { Button } from "@/components/ui/button";
import { cn } from "../lib/utils";
import { chatApi } from "../api/chat";

interface SpecContent {
  what: string;
  why: string;
  constraints: string;
  success: string;
}

interface ChatSpecCardProps {
  content: string;
  messageId?: string;
  conversationId?: string;
  onHandoff?: (spec: SpecContent) => void;
}

export function ChatSpecCard({ content, messageId, conversationId, onHandoff }: ChatSpecCardProps) {
  let parsedSpec: SpecContent | null = null;
  try {
    parsedSpec = JSON.parse(content) as SpecContent;
  } catch {
    return (
      <div className="text-destructive text-[13px]">Could not render spec.</div>
    );
  }

  return <ChatSpecCardInner spec={parsedSpec} messageId={messageId} conversationId={conversationId} onHandoff={onHandoff} />;
}

function ChatSpecCardInner({
  spec: initialSpec,
  messageId,
  conversationId,
  onHandoff,
}: {
  spec: SpecContent;
  messageId?: string;
  conversationId?: string;
  onHandoff?: (spec: SpecContent) => void;
}) {
  const [isEditing, setIsEditing] = useState(false);
  const [isDraft, setIsDraft] = useState(false);
  const [isSubmitting, setIsSubmitting] = useState(false);
  const [spec, setSpec] = useState<SpecContent>(initialSpec);
  const [editedSpec, setEditedSpec] = useState<SpecContent>(initialSpec);

  const allFieldsEmpty =
    !editedSpec.what.trim() &&
    !editedSpec.why.trim() &&
    !editedSpec.constraints.trim() &&
    !editedSpec.success.trim();

  function handleDiscard() {
    setEditedSpec(spec);
    setIsEditing(false);
  }

  async function handleSaveChanges() {
    setSpec(editedSpec);
    setIsEditing(false);
    if (conversationId && messageId) {
      await chatApi.editMessage(conversationId, messageId, JSON.stringify(editedSpec));
    }
  }

  async function handleSendToPM() {
    setIsSubmitting(true);
    try {
      onHandoff?.(spec);
    } finally {
      setIsSubmitting(false);
    }
  }

  if (isEditing) {
    return (
      <div
        role="region"
        aria-label="Specification"
        className={cn(
          "motion-safe:animate-in motion-safe:fade-in motion-safe:slide-in-from-bottom-2",
          "rounded-lg border border-border bg-card p-4 max-w-[480px]"
        )}
      >
        <div className="space-y-4">
          <div>
            <p className="text-[11px] font-semibold uppercase tracking-wide text-muted-foreground">What</p>
            <textarea
              value={editedSpec.what}
              onChange={(e) => setEditedSpec((s) => ({ ...s, what: e.target.value }))}
              aria-label="What to build"
              placeholder="What should be built?"
              className="mt-1 w-full rounded-md border border-input bg-transparent px-3 py-2 text-sm resize-none min-h-[60px] focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring"
              tabIndex={1}
              onKeyDown={(e) => {
                if (e.key === "Escape") handleDiscard();
              }}
            />
          </div>
          <div>
            <p className="text-[11px] font-semibold uppercase tracking-wide text-muted-foreground">Why</p>
            <textarea
              value={editedSpec.why}
              onChange={(e) => setEditedSpec((s) => ({ ...s, why: e.target.value }))}
              aria-label="Why it matters"
              placeholder="Why is this important?"
              className="mt-1 w-full rounded-md border border-input bg-transparent px-3 py-2 text-sm resize-none min-h-[60px] focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring"
              tabIndex={2}
              onKeyDown={(e) => {
                if (e.key === "Escape") handleDiscard();
              }}
            />
          </div>
          <div>
            <p className="text-[11px] font-semibold uppercase tracking-wide text-muted-foreground">Constraints</p>
            <textarea
              value={editedSpec.constraints}
              onChange={(e) => setEditedSpec((s) => ({ ...s, constraints: e.target.value }))}
              aria-label="Constraints"
              placeholder="Any constraints or requirements?"
              className="mt-1 w-full rounded-md border border-input bg-transparent px-3 py-2 text-sm resize-none min-h-[60px] focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring"
              tabIndex={3}
              onKeyDown={(e) => {
                if (e.key === "Escape") handleDiscard();
              }}
            />
          </div>
          <div>
            <p className="text-[11px] font-semibold uppercase tracking-wide text-muted-foreground">Success</p>
            <textarea
              value={editedSpec.success}
              onChange={(e) => setEditedSpec((s) => ({ ...s, success: e.target.value }))}
              aria-label="Success criteria"
              placeholder="How will success be measured?"
              className="mt-1 w-full rounded-md border border-input bg-transparent px-3 py-2 text-sm resize-none min-h-[60px] focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring"
              tabIndex={4}
              onKeyDown={(e) => {
                if (e.key === "Escape") handleDiscard();
              }}
            />
          </div>
        </div>
        <div className="flex gap-2 pt-4 border-t border-border mt-4">
          <Button
            variant="default"
            size="sm"
            disabled={allFieldsEmpty}
            onClick={handleSaveChanges}
            tabIndex={5}
          >
            Save changes
          </Button>
          <Button
            variant="ghost"
            size="sm"
            onClick={handleDiscard}
            tabIndex={6}
          >
            Discard
          </Button>
        </div>
      </div>
    );
  }

  return (
    <div
      role="region"
      aria-label="Specification"
      aria-busy={isSubmitting ? "true" : undefined}
      aria-disabled={isSubmitting ? "true" : undefined}
      className={cn(
        "motion-safe:animate-in motion-safe:fade-in motion-safe:slide-in-from-bottom-2",
        "rounded-lg border border-border bg-card p-4 max-w-[480px]"
      )}
    >
      {isDraft && (
        <p className="text-[11px] text-muted-foreground ml-2 mb-2">[Draft]</p>
      )}
      <div className="space-y-4">
        <div>
          <p className="text-[11px] font-semibold uppercase tracking-wide text-muted-foreground">What</p>
          <p className="text-[15px] font-normal text-foreground leading-relaxed">{spec.what}</p>
        </div>
        <div>
          <p className="text-[11px] font-semibold uppercase tracking-wide text-muted-foreground">Why</p>
          <p className="text-[15px] font-normal text-foreground leading-relaxed">{spec.why}</p>
        </div>
        <div>
          <p className="text-[11px] font-semibold uppercase tracking-wide text-muted-foreground">Constraints</p>
          <p className="text-[15px] font-normal text-foreground leading-relaxed">{spec.constraints}</p>
        </div>
        <div>
          <p className="text-[11px] font-semibold uppercase tracking-wide text-muted-foreground">Success</p>
          <p className="text-[15px] font-normal text-foreground leading-relaxed">{spec.success}</p>
        </div>
      </div>
      <div className="flex gap-2 pt-4 border-t border-border mt-4">
        <Button
          variant="default"
          size="sm"
          disabled={isSubmitting}
          onClick={handleSendToPM}
          aria-disabled={isSubmitting ? "true" : undefined}
        >
          Send to PM
        </Button>
        <Button
          variant="outline"
          size="sm"
          disabled={isSubmitting}
          onClick={() => {
            setEditedSpec(spec);
            setIsEditing(true);
          }}
        >
          Edit
        </Button>
        <Button
          variant="ghost"
          size="sm"
          disabled={isSubmitting}
          onClick={() => setIsDraft(true)}
        >
          Save as Draft
        </Button>
      </div>
    </div>
  );
}