import type { AgentToolResult, ToolRenderResultOptions } from "@earendil-works/pi-coding-agent";
import { Text } from "@earendil-works/pi-tui";

type McpToolResultDetails = Record<string, unknown> & { error?: unknown };
type McpToolContentBlock = AgentToolResult<McpToolResultDetails>["content"][number];

interface RenderTheme {
  fg: (name: string, text: string) => string;
}

interface McpToolRenderContext {
  isError: boolean;
}

export interface McpToolResultDisplay {
  lines: string[];
  truncated: boolean;
}

function blockToLines(block: McpToolContentBlock): string[] {
  if (block.type === "text") {
    return block.text.split("\n");
  }
  return [`[image: ${block.mimeType}]`];
}

export function formatMcpToolResultLines(
  result: Pick<AgentToolResult<McpToolResultDetails>, "content">,
  expanded: boolean,
  maxCollapsedLines = 3,
): McpToolResultDisplay {
  const allLines = result.content.flatMap(blockToLines);
  const lines = allLines.length > 0 ? allLines : ["(empty result)"];

  if (expanded || lines.length <= maxCollapsedLines) {
    return { lines, truncated: false };
  }

  return {
    lines: [...lines.slice(0, maxCollapsedLines), "…"],
    truncated: true,
  };
}

export function renderMcpToolResult(
  result: AgentToolResult<McpToolResultDetails>,
  options: ToolRenderResultOptions,
  theme: RenderTheme,
  context?: McpToolRenderContext,
) {
  if (options.isPartial) {
    return new Text(theme.fg("warning", "Running MCP tool..."), 0, 0);
  }

  const hasErrorDetails = Boolean(result.details.error);
  const display = formatMcpToolResultLines(result, options.expanded || context?.isError === true || hasErrorDetails);
  const output = display.lines
    .map((line) => line === "…" ? theme.fg("muted", line) : theme.fg("toolOutput", line))
    .join("\n");
  const hint = display.truncated && !options.expanded
    ? `\n${theme.fg("muted", "(Ctrl+O to expand)")}`
    : "";

  return new Text(`${output}${hint}`, 0, 0);
}