import { paintFrameBackgroundClears, paintFrameBackgroundLines, padFrameRows, resolveFrameBackgroundAnsi } from "../theme/frame-background.js";
import { getOriginalTuiMethod, rememberTuiMethodWrapper } from "./tui-proxy-original.js";
import { profileCount } from "./profiler.js";

const PATCHED = Symbol.for("pi-droid-styling.render-frame-background.patched");
const WRITE_PATCHED = Symbol.for("pi-droid-styling.render-frame-background.write-patched");

type ApplyLineResetsFunction = (lines: string[]) => string[];

type TuiLike = {
	applyLineResets?: ApplyLineResetsFunction;
	terminal?: TerminalLike;
	[PATCHED]?: FrameBackgroundApplyLineResetsPatch | ApplyLineResetsFunction | boolean;
};

type TerminalWriteFunction = (data: string) => unknown;

type TerminalLike = {
	columns?: number;
	rows?: number;
	write?: TerminalWriteFunction;
	[WRITE_PATCHED]?: FrameBackgroundWritePatch;
};

type FrameBackgroundApplyLineResetsPatch = {
	theme: any;
	wrapper: ApplyLineResetsFunction;
};

type FrameBackgroundWritePatch = {
	theme: any;
	wrapper: TerminalWriteFunction;
};

function readRows(tui: TuiLike): number {
	const rows = tui.terminal?.rows;
	return typeof rows === "number" && Number.isFinite(rows) ? Math.max(1, Math.floor(rows)) : 0;
}

function readColumns(tui: TuiLike): number {
	const columns = tui.terminal?.columns;
	return typeof columns === "number" && Number.isFinite(columns) ? Math.max(1, Math.floor(columns)) : 0;
}

function installFrameBackgroundClearWriter(tui: TuiLike, theme: any): void {
	const terminal = tui.terminal;
	if (!terminal || typeof terminal.write !== "function") return;
	const existingPatch = terminal[WRITE_PATCHED];
	if (existingPatch && terminal.write === existingPatch.wrapper) {
		existingPatch.theme = theme;
		return;
	}

	const originalWrite = terminal.write.bind(terminal);
	const patch: FrameBackgroundWritePatch = {
		theme,
		wrapper(data: string): unknown {
			const text = String(data);
			const bgAnsi = resolveFrameBackgroundAnsi(patch.theme);
			return originalWrite(bgAnsi ? paintFrameBackgroundClears(text, bgAnsi) : text);
		},
	};
	terminal[WRITE_PATCHED] = patch;
	terminal.write = patch.wrapper;
}

export function installRenderFrameBackground(tui: TuiLike, theme: any): void {
	if (process.env.PI_DROID_RENDER_FRAME_BG === "0") return;
	if (!tui || typeof tui.applyLineResets !== "function") return;
	installFrameBackgroundClearWriter(tui, theme);
	const existingPatch = tui[PATCHED];
	if (existingPatch && typeof existingPatch === "object" && tui.applyLineResets === existingPatch.wrapper) {
		existingPatch.theme = theme;
		return;
	}
	if (typeof existingPatch === "function" && tui.applyLineResets === existingPatch) return;
	if (existingPatch === true && tui.applyLineResets.name === "droidFrameBackgroundApplyLineResets") return;

	const originalApplyLineResets = getOriginalTuiMethod(tui, "applyLineResets");
	const patch: FrameBackgroundApplyLineResetsPatch = {
		theme,
		wrapper: function droidFrameBackgroundApplyLineResets(this: TuiLike, lines: string[]): string[] {
			const bgAnsi = resolveFrameBackgroundAnsi(patch.theme);
			if (!bgAnsi) return originalApplyLineResets.call(this, lines) as string[];
			const frameLines = padFrameRows(lines, readRows(this));
			const resetLines = originalApplyLineResets.call(this, frameLines) as string[];
			profileCount("render.frameBackground.row", resetLines.length);
			return paintFrameBackgroundLines(resetLines, bgAnsi, readColumns(this));
		},
	};

	tui[PATCHED] = patch;
	tui.applyLineResets = patch.wrapper;
	rememberTuiMethodWrapper(tui, "applyLineResets", patch.wrapper);
}