import { useRef } from "react";
import { Maximize2, RotateCw } from "lucide-react";
import { TerminalView } from "./TerminalView";
import { StatusRing } from "./StatusRing";
import { COLORS, FONT, STATE_COLOR } from "./theme";
import type { LayoutNode, SurfaceState, SurfaceView } from "./layoutTypes";
import { setRatios, restartSurface } from "./socketBridge";

interface Props {
  workspaceId: string;
  layout: LayoutNode | null;
  /** surface_id -> running flag, from the latest status/events. */
  running: Record<string, boolean>;
  states: Record<string, SurfaceState>;
  surfaces: Record<string, SurfaceView>;
  focusedId: string | null;
  onFocus: (id: string) => void;
}

/** Collapse an absolute cwd into a ~/<leaf> style label for the panel header. */
function shortPath(cwd: string): string {
  const leaf = cwd.split("/").filter(Boolean).pop();
  return leaf ? `~/${leaf}` : cwd;
}

export function LayoutEngine({ workspaceId, layout, running, states, surfaces, focusedId, onFocus }: Props) {
  if (!layout) {
    return <div style={{ color: COLORS.textMuted, padding: 24 }}>Empty workspace — apply a preset to add panels.</div>;
  }
  return (
    <div style={{ width: "100%", height: "100%", padding: 12, boxSizing: "border-box" }}>
      <Node workspaceId={workspaceId} node={layout} path={[]} running={running} states={states} surfaces={surfaces} focusedId={focusedId} onFocus={onFocus} />
    </div>
  );
}

function Node({ workspaceId, node, path, running, states, surfaces, focusedId, onFocus }: {
  workspaceId: string; node: LayoutNode; path: number[];
  running: Record<string, boolean>; states: Record<string, SurfaceState>;
  surfaces: Record<string, SurfaceView>; focusedId: string | null; onFocus: (id: string) => void;
}) {
  if ("leaf" in node) {
    const id = node.leaf.surface_id;
    const focused = focusedId === id;
    const card = (inner: React.ReactNode) => (
      <div
        onMouseDown={() => onFocus(id)}
        style={{
          display: "flex", flexDirection: "column", width: "100%", height: "100%",
          background: COLORS.bgPanel, borderRadius: 8, overflow: "hidden",
          border: focused ? `2px solid ${COLORS.accent}` : `1px solid ${COLORS.borderSubtle}`,
          boxSizing: "border-box",
        }}
      >
        {inner}
      </div>
    );

    if (running[id] === false) {
      return card(
        <div style={{ display: "flex", alignItems: "center", justifyContent: "center", height: "100%", width: "100%", color: COLORS.textSecondary, flexDirection: "column", gap: 10 }}>
          <div style={{ fontFamily: FONT.mono, fontSize: 13 }}>Process exited</div>
          <button onClick={() => void restartSurface(id)}
            style={{ display: "flex", alignItems: "center", gap: 6, padding: "6px 14px", background: COLORS.bgElevated, color: COLORS.textPrimary, border: `1px solid ${COLORS.borderStrong}`, borderRadius: 7, fontSize: 12 }}>
            <RotateCw size={13} /> Restart
          </button>
        </div>
      );
    }

    const spec = surfaces[id]?.spec;
    const agent = spec?.agent_label ?? "shell";
    const state = states[id] ?? "idle";
    return card(
      <>
        <div style={{ display: "flex", alignItems: "center", gap: 8, height: 30, flex: "0 0 30px", padding: "0 10px", background: COLORS.bgElevated, borderBottom: `1px solid ${COLORS.borderSubtle}` }}>
          <StatusRing state={state} running={true} />
          <span style={{ fontFamily: FONT.mono, fontSize: 12, fontWeight: 600, color: COLORS.textPrimary }}>{agent}</span>
          {spec?.cwd && <span style={{ fontFamily: FONT.mono, fontSize: 11, color: COLORS.textMuted, whiteSpace: "nowrap", overflow: "hidden", textOverflow: "ellipsis" }}>{shortPath(spec.cwd)}</span>}
          <span style={{ flex: 1 }} />
          <span style={{ display: "flex", alignItems: "center", height: 16, padding: "0 7px", borderRadius: 8, background: "#000", fontFamily: FONT.mono, fontSize: 10, fontWeight: 600, color: STATE_COLOR[state] }}>
            {state}
          </span>
          <Maximize2 size={13} color={COLORS.textMuted} style={{ cursor: "pointer" }} aria-label="Zoom (mock)" />
        </div>
        <div style={{ flex: 1, minHeight: 0 }}>
          <TerminalView key={id} surfaceId={id} />
        </div>
      </>
    );
  }

  const { orient, ratios, children } = node.split;
  const dir = orient === "h" ? "row" : "column";
  return (
    <div style={{ display: "flex", flexDirection: dir, width: "100%", height: "100%" }}>
      {children.map((child, i) => (
        <Pane key={i} grow={ratios[i] ?? 1} isLast={i === children.length - 1} orient={orient}
          onResize={(deltaFrac) => {
            const next = [...ratios];
            next[i] = Math.max(0.05, next[i] + deltaFrac);
            next[i + 1] = Math.max(0.05, (next[i + 1] ?? 1) - deltaFrac);
            void setRatios(workspaceId, path, next);
          }}>
          <Node workspaceId={workspaceId} node={child} path={[...path, i]} running={running} states={states} surfaces={surfaces} focusedId={focusedId} onFocus={onFocus} />
        </Pane>
      ))}
    </div>
  );
}

function Pane({ grow, isLast, orient, onResize, children }: { grow: number; isLast: boolean; orient: "h" | "v"; onResize: (deltaFrac: number) => void; children: React.ReactNode }) {
  const ref = useRef<HTMLDivElement>(null);
  const startDrag = (e: React.MouseEvent) => {
    e.preventDefault();
    const parent = ref.current?.parentElement;
    if (!parent) return;
    const total = orient === "h" ? parent.clientWidth : parent.clientHeight;
    let last = orient === "h" ? e.clientX : e.clientY;
    const move = (ev: MouseEvent) => {
      const cur = orient === "h" ? ev.clientX : ev.clientY;
      const delta = (cur - last) / total;
      last = cur;
      onResize(delta);
    };
    const up = () => {
      window.removeEventListener("mousemove", move);
      window.removeEventListener("mouseup", up);
    };
    window.addEventListener("mousemove", move);
    window.addEventListener("mouseup", up);
  };
  return (
    <>
      <div ref={ref} style={{ flexGrow: grow, flexBasis: 0, minWidth: 0, minHeight: 0, overflow: "hidden", position: "relative" }}>
        {children}
      </div>
      {!isLast && (
        <div onMouseDown={startDrag}
          style={{
            flex: "0 0 10px",
            cursor: orient === "h" ? "col-resize" : "row-resize",
            background: "transparent",
          }} />
      )}
    </>
  );
}