/**
 * Syntax highlighting for pi-crew UI.
 *
 * Uses cli-highlight (sync) with the active Pi theme's syntax colors.
 * Falls back to plain text (theme.fg on every line) if the language is
 * unsupported or highlighting fails.
 */
import { createRequire } from "node:module";
import type { CrewTheme } from "./theme-adapter.ts";
import { asCrewTheme } from "./theme-adapter.ts";

// PERF-1: cli-highlight loads highlight.js (~190 grammars) at require() time,
// adding 50-150ms to every cold start if imported eagerly at bundle load.
// highlight() is only called from SYNC render paths (highlightCode /
// highlightJson), so it MUST stay sync — lazy-load via a synchronous
// createRequire shim on first use instead (same mechanism as
// skills/validate.ts's yaml / utils/git.ts's hosted-git-info). In the esbuild
// bundle cli-highlight stays external and resolves through this same shim.
const require = createRequire(import.meta.url);
type CliHighlight = typeof import("cli-highlight");
let cached: CliHighlight | undefined;
function cliHighlight(): CliHighlight {
	if (!cached) cached = require("cli-highlight") as CliHighlight;
	return cached;
}

// ── cli-highlight theme bridge ──────────────────────────────────────────

function buildCliTheme(theme: CrewTheme): Record<string, (text: string) => string> {
	return {
		keyword: (text) => theme.fg("syntaxKeyword", text),
		built_in: (text) => theme.fg("syntaxType", text),
		literal: (text) => theme.fg("syntaxNumber", text),
		number: (text) => theme.fg("syntaxNumber", text),
		string: (text) => theme.fg("syntaxString", text),
		comment: (text) => theme.fg("syntaxComment", text),
		function: (text) => theme.fg("syntaxFunction", text),
		title: (text) => theme.fg("syntaxFunction", text),
		class: (text) => theme.fg("syntaxType", text),
		type: (text) => theme.fg("syntaxType", text),
		attr: (text) => theme.fg("syntaxVariable", text),
		variable: (text) => theme.fg("syntaxVariable", text),
		params: (text) => theme.fg("syntaxVariable", text),
		operator: (text) => theme.fg("syntaxOperator", text),
		punctuation: (text) => theme.fg("syntaxPunctuation", text),
	};
}

function hlCliSync(code: string, language: string | undefined, theme: CrewTheme): string {
	if (!language) {
		return code
			.split("\n")
			.map((line) => theme.fg("mdCodeBlock", line))
			.join("\n");
	}
	try {
		return cliHighlight()
			.highlight(code, {
				language,
				ignoreIllegals: true,
				theme: buildCliTheme(theme),
			})
			.trimEnd();
	} catch {
		return code
			.split("\n")
			.map((line) => theme.fg("mdCodeBlock", line))
			.join("\n");
	}
}

// ── Language detection ──────────────────────────────────────────────────

export const languageMap: Record<string, string> = {
	ts: "typescript",
	tsx: "typescript",
	js: "javascript",
	jsx: "javascript",
	mjs: "javascript",
	cjs: "javascript",
	py: "python",
	md: "markdown",
	markdown: "markdown",
	json: "json",
	yml: "yaml",
	yaml: "yaml",
	toml: "yaml",
	html: "html",
	htm: "html",
	css: "css",
	scss: "scss",
	sass: "sass",
	bash: "bash",
	sh: "bash",
	zsh: "bash",
	fish: "bash",
	ps1: "powershell",
	sql: "sql",
	rust: "rust",
	rb: "ruby",
	go: "go",
	java: "java",
	kt: "kotlin",
	cpp: "cpp",
	cc: "cpp",
	cxx: "cpp",
	hpp: "cpp",
	c: "c",
	h: "c",
	cs: "csharp",
	php: "php",
};

/** @internal */
function detectLanguageFromPath(filePath: string): string | undefined {
	const ext = filePath.split(".").pop()?.toLowerCase();
	if (!ext) return undefined;
	return languageMap[ext];
}

// ── Public API ──────────────────────────────────────────────────────────

export function highlightCode(code: string, language: string | undefined, themeLike: unknown = undefined): string {
	const theme = asCrewTheme(themeLike);
	const validLanguage = language && cliHighlight().supportsLanguage(language) ? language : undefined;
	return hlCliSync(code, validLanguage, theme);
}

export function highlightJson(payload: string, themeLike: unknown = undefined): string {
	const theme = asCrewTheme(themeLike);
	try {
		return cliHighlight()
			.highlight(payload, {
				language: "json",
				ignoreIllegals: true,
				theme: buildCliTheme(theme),
			})
			.trimEnd();
	} catch {
		try {
			const parsed = JSON.parse(payload);
			return JSON.stringify(parsed, null, 2)
				.split("\n")
				.map((line) => theme.fg("mdCodeBlock", line))
				.join("\n");
		} catch {
			return payload
				.split("\n")
				.map((line) => theme.fg("mdCodeBlock", line))
				.join("\n");
		}
	}
}

export { detectLanguageFromPath };