/**
 * `ProjectContextPanel` — edits the shared project context stored in
 * `.ideai/CONTEXT.md`.
 *
 * This context is injected into every agent launch before the agent persona,
 * regardless of the selected AI profile/model.
 */

import { useEffect, useState } from "react";

import type { GatewayError } from "@/domain";
import { Button, Panel, Spinner, cn } from "@/shared";
import { useGateways } from "@/app/di";

export interface ProjectContextPanelProps {
  /** Project whose `.ideai/CONTEXT.md` should be edited. */
  projectId: string;
}

function describe(e: unknown): string {
  if (e && typeof e === "object" && "message" in e) {
    return String((e as GatewayError).message);
  }
  return String(e);
}

export function ProjectContextPanel({ projectId }: ProjectContextPanelProps) {
  const { project } = useGateways();
  const [content, setContent] = useState("");
  const [savedContent, setSavedContent] = useState("");
  const [busy, setBusy] = useState(false);
  const [error, setError] = useState<string | null>(null);

  useEffect(() => {
    let cancelled = false;
    setBusy(true);
    setError(null);
    project
      .readProjectContext(projectId)
      .then((text) => {
        if (!cancelled) {
          setContent(text);
          setSavedContent(text);
        }
      })
      .catch((e) => {
        if (!cancelled) setError(describe(e));
      })
      .finally(() => {
        if (!cancelled) setBusy(false);
      });
    return () => {
      cancelled = true;
    };
  }, [project, projectId]);

  async function save() {
    setBusy(true);
    setError(null);
    try {
      await project.updateProjectContext(projectId, content);
      setSavedContent(content);
    } catch (e) {
      setError(describe(e));
    } finally {
      setBusy(false);
    }
  }

  const dirty = content !== savedContent;

  return (
    <Panel title="Project Context" className="flex flex-col gap-0">
      {error && (
        <p
          role="alert"
          className="mx-4 mt-3 rounded-md border border-danger/40 bg-danger/10 px-3 py-2 text-sm text-danger"
        >
          {error}
        </p>
      )}

      <div className="border-b border-border px-4 py-2">
        <code className="text-xs text-muted">.ideai/CONTEXT.md</code>
      </div>

      <div className="flex flex-col gap-3 p-4">
        <textarea
          aria-label="project context"
          value={content}
          onChange={(e) => setContent(e.target.value)}
          rows={18}
          className={cn(
            "w-full rounded-md bg-raised px-3 py-2 text-sm text-content",
            "border border-border outline-none transition-colors",
            "focus:border-primary placeholder:text-faint",
            "disabled:cursor-not-allowed disabled:opacity-50 resize-y font-mono",
          )}
          disabled={busy}
        />

        <div className="flex items-center justify-end gap-2">
          {busy && <Spinner size={14} />}
          <Button
            variant="primary"
            disabled={busy || !dirty}
            onClick={() => void save()}
          >
            Save
          </Button>
        </div>
      </div>
    </Panel>
  );
}