import chalk from "chalk";
import { marked, type Token } from "marked";
import type { Component } from "../tui.js";
import { visibleWidth } from "../utils.js";

type Color =
	| "black"
	| "red"
	| "green"
	| "yellow"
	| "blue"
	| "magenta"
	| "cyan"
	| "white"
	| "gray"
	| "bgBlack"
	| "bgRed"
	| "bgGreen"
	| "bgYellow"
	| "bgBlue"
	| "bgMagenta"
	| "bgCyan"
	| "bgWhite"
	| "bgGray";

export class Markdown implements Component {
	private text: string;
	private bgColor?: Color;
	private fgColor?: Color;
	private customBgRgb?: { r: number; g: number; b: number };
	private paddingX: number; // Left/right padding
	private paddingY: number; // Top/bottom padding

	// Cache for rendered output
	private cachedText?: string;
	private cachedWidth?: number;
	private cachedLines?: string[];

	constructor(
		text: string = "",
		bgColor?: Color,
		fgColor?: Color,
		customBgRgb?: { r: number; g: number; b: number },
		paddingX: number = 1,
		paddingY: number = 1,
	) {
		this.text = text;
		this.bgColor = bgColor;
		this.fgColor = fgColor;
		this.customBgRgb = customBgRgb;
		this.paddingX = paddingX;
		this.paddingY = paddingY;
	}

	setText(text: string): void {
		this.text = text;
		// Invalidate cache when text changes
		this.cachedText = undefined;
		this.cachedWidth = undefined;
		this.cachedLines = undefined;
	}

	setBgColor(bgColor?: Color): void {
		this.bgColor = bgColor;
		// Invalidate cache when color changes
		this.cachedText = undefined;
		this.cachedWidth = undefined;
		this.cachedLines = undefined;
	}

	setFgColor(fgColor?: Color): void {
		this.fgColor = fgColor;
		// Invalidate cache when color changes
		this.cachedText = undefined;
		this.cachedWidth = undefined;
		this.cachedLines = undefined;
	}

	setCustomBgRgb(customBgRgb?: { r: number; g: number; b: number }): void {
		this.customBgRgb = customBgRgb;
		// Invalidate cache when color changes
		this.cachedText = undefined;
		this.cachedWidth = undefined;
		this.cachedLines = undefined;
	}

	render(width: number): string[] {
		// Check cache
		if (this.cachedLines && this.cachedText === this.text && this.cachedWidth === width) {
			return this.cachedLines;
		}

		// Calculate available width for content (subtract horizontal padding)
		const contentWidth = Math.max(1, width - this.paddingX * 2);

		// Don't render anything if there's no actual text
		if (!this.text || this.text.trim() === "") {
			const result: string[] = [];
			// Update cache
			this.cachedText = this.text;
			this.cachedWidth = width;
			this.cachedLines = result;
			return result;
		}

		// Replace tabs with 3 spaces for consistent rendering
		const normalizedText = this.text.replace(/\t/g, "   ");

		// Parse markdown to HTML-like tokens
		const tokens = marked.lexer(normalizedText);

		// Convert tokens to styled terminal output
		const renderedLines: string[] = [];

		for (let i = 0; i < tokens.length; i++) {
			const token = tokens[i];
			const nextToken = tokens[i + 1];
			const tokenLines = this.renderToken(token, contentWidth, nextToken?.type);
			renderedLines.push(...tokenLines);
		}

		// Wrap lines to fit content width
		const wrappedLines: string[] = [];
		for (const line of renderedLines) {
			wrappedLines.push(...this.wrapLine(line, contentWidth));
		}

		// Add padding and apply colors
		const leftPad = " ".repeat(this.paddingX);
		const paddedLines: string[] = [];

		for (const line of wrappedLines) {
			// Calculate visible length
			const visibleLength = visibleWidth(line);
			// Right padding to fill to width (accounting for left padding and content)
			const rightPadLength = Math.max(0, width - this.paddingX - visibleLength);
			const rightPad = " ".repeat(rightPadLength);

			// Add left padding, content, and right padding
			let paddedLine = leftPad + line + rightPad;

			// Apply foreground color if specified
			if (this.fgColor) {
				paddedLine = (chalk as any)[this.fgColor](paddedLine);
			}

			// Apply background color if specified
			if (this.customBgRgb) {
				paddedLine = chalk.bgRgb(this.customBgRgb.r, this.customBgRgb.g, this.customBgRgb.b)(paddedLine);
			} else if (this.bgColor) {
				paddedLine = (chalk as any)[this.bgColor](paddedLine);
			}

			paddedLines.push(paddedLine);
		}

		// Add top padding (empty lines)
		const emptyLine = " ".repeat(width);
		const topPadding: string[] = [];
		for (let i = 0; i < this.paddingY; i++) {
			let emptyPaddedLine = emptyLine;
			if (this.customBgRgb) {
				emptyPaddedLine = chalk.bgRgb(this.customBgRgb.r, this.customBgRgb.g, this.customBgRgb.b)(emptyPaddedLine);
			} else if (this.bgColor) {
				emptyPaddedLine = (chalk as any)[this.bgColor](emptyPaddedLine);
			}
			topPadding.push(emptyPaddedLine);
		}

		// Add bottom padding (empty lines)
		const bottomPadding: string[] = [];
		for (let i = 0; i < this.paddingY; i++) {
			let emptyPaddedLine = emptyLine;
			if (this.customBgRgb) {
				emptyPaddedLine = chalk.bgRgb(this.customBgRgb.r, this.customBgRgb.g, this.customBgRgb.b)(emptyPaddedLine);
			} else if (this.bgColor) {
				emptyPaddedLine = (chalk as any)[this.bgColor](emptyPaddedLine);
			}
			bottomPadding.push(emptyPaddedLine);
		}

		// Combine top padding, content, and bottom padding
		const result = [...topPadding, ...paddedLines, ...bottomPadding];

		// Update cache
		this.cachedText = this.text;
		this.cachedWidth = width;
		this.cachedLines = result;

		return result.length > 0 ? result : [""];
	}

	private renderToken(token: Token, width: number, nextTokenType?: string): string[] {
		const lines: string[] = [];

		switch (token.type) {
			case "heading": {
				const headingLevel = token.depth;
				const headingPrefix = "#".repeat(headingLevel) + " ";
				const headingText = this.renderInlineTokens(token.tokens || []);
				if (headingLevel === 1) {
					lines.push(chalk.bold.underline.yellow(headingText));
				} else if (headingLevel === 2) {
					lines.push(chalk.bold.yellow(headingText));
				} else {
					lines.push(chalk.bold(headingPrefix + headingText));
				}
				lines.push(""); // Add spacing after headings
				break;
			}

			case "paragraph": {
				const paragraphText = this.renderInlineTokens(token.tokens || []);
				lines.push(paragraphText);
				// Don't add spacing if next token is space or list
				if (nextTokenType && nextTokenType !== "list" && nextTokenType !== "space") {
					lines.push("");
				}
				break;
			}

			case "code": {
				lines.push(chalk.gray("```" + (token.lang || "")));
				// Split code by newlines and style each line
				const codeLines = token.text.split("\n");
				for (const codeLine of codeLines) {
					lines.push(chalk.dim("  ") + chalk.green(codeLine));
				}
				lines.push(chalk.gray("```"));
				lines.push(""); // Add spacing after code blocks
				break;
			}

			case "list": {
				const listLines = this.renderList(token as any, 0);
				lines.push(...listLines);
				// Don't add spacing after lists if a space token follows
				// (the space token will handle it)
				break;
			}

			case "table": {
				const tableLines = this.renderTable(token as any);
				lines.push(...tableLines);
				break;
			}

			case "blockquote": {
				const quoteText = this.renderInlineTokens(token.tokens || []);
				const quoteLines = quoteText.split("\n");
				for (const quoteLine of quoteLines) {
					lines.push(chalk.gray("│ ") + chalk.italic(quoteLine));
				}
				lines.push(""); // Add spacing after blockquotes
				break;
			}

			case "hr":
				lines.push(chalk.gray("─".repeat(Math.min(width, 80))));
				lines.push(""); // Add spacing after horizontal rules
				break;

			case "html":
				// Skip HTML for terminal output
				break;

			case "space":
				// Space tokens represent blank lines in markdown
				lines.push("");
				break;

			default:
				// Handle any other token types as plain text
				if ("text" in token && typeof token.text === "string") {
					lines.push(token.text);
				}
		}

		return lines;
	}

	private renderInlineTokens(tokens: Token[]): string {
		let result = "";

		for (const token of tokens) {
			switch (token.type) {
				case "text":
					// Text tokens in list items can have nested tokens for inline formatting
					if (token.tokens && token.tokens.length > 0) {
						result += this.renderInlineTokens(token.tokens);
					} else {
						result += token.text;
					}
					break;

				case "strong":
					result += chalk.bold(this.renderInlineTokens(token.tokens || []));
					break;

				case "em":
					result += chalk.italic(this.renderInlineTokens(token.tokens || []));
					break;

				case "codespan":
					result += chalk.gray("`") + chalk.cyan(token.text) + chalk.gray("`");
					break;

				case "link": {
					const linkText = this.renderInlineTokens(token.tokens || []);
					// If link text matches href, only show the link once
					if (linkText === token.href) {
						result += chalk.underline.blue(linkText);
					} else {
						result += chalk.underline.blue(linkText) + chalk.gray(` (${token.href})`);
					}
					break;
				}

				case "br":
					result += "\n";
					break;

				case "del":
					result += chalk.strikethrough(this.renderInlineTokens(token.tokens || []));
					break;

				default:
					// Handle any other inline token types as plain text
					if ("text" in token && typeof token.text === "string") {
						result += token.text;
					}
			}
		}

		return result;
	}

	private wrapLine(line: string, width: number): string[] {
		// Handle ANSI escape codes properly when wrapping
		const wrapped: string[] = [];

		// Handle undefined or null lines
		if (!line) {
			return [""];
		}

		// Split by newlines first - wrap each line individually
		const splitLines = line.split("\n");
		for (const splitLine of splitLines) {
			const visibleLength = visibleWidth(splitLine);

			if (visibleLength <= width) {
				wrapped.push(splitLine);
				continue;
			}

			// This line needs wrapping
			wrapped.push(...this.wrapSingleLine(splitLine, width));
		}

		return wrapped.length > 0 ? wrapped : [""];
	}

	private wrapSingleLine(line: string, width: number): string[] {
		const wrapped: string[] = [];

		// Track active ANSI codes to preserve them across wrapped lines
		const activeAnsiCodes: string[] = [];
		let currentLine = "";
		let currentLength = 0;
		let i = 0;

		while (i < line.length) {
			if (line[i] === "\x1b" && line[i + 1] === "[") {
				// ANSI escape sequence - parse and track it
				let j = i + 2;
				while (j < line.length && line[j] && !/[mGKHJ]/.test(line[j]!)) {
					j++;
				}
				if (j < line.length) {
					const ansiCode = line.substring(i, j + 1);
					currentLine += ansiCode;

					// Track styling codes (ending with 'm')
					if (line[j] === "m") {
						// Reset code
						if (ansiCode === "\x1b[0m" || ansiCode === "\x1b[m") {
							activeAnsiCodes.length = 0;
						} else {
							// Add to active codes (replacing similar ones)
							activeAnsiCodes.push(ansiCode);
						}
					}

					i = j + 1;
				} else {
					// Incomplete ANSI sequence at end - don't include it
					break;
				}
			} else {
				// Regular character - extract full grapheme cluster
				// Handle multi-byte characters (emoji, surrogate pairs, etc.)
				let char: string;
				let charByteLength: number;

				// Check for surrogate pair (emoji and other multi-byte chars)
				const codePoint = line.charCodeAt(i);
				if (codePoint >= 0xd800 && codePoint <= 0xdbff && i + 1 < line.length) {
					// High surrogate - get the pair
					char = line.substring(i, i + 2);
					charByteLength = 2;
				} else {
					// Regular character
					char = line[i];
					charByteLength = 1;
				}

				const charWidth = visibleWidth(char);

				// Check if adding this character would exceed width
				if (currentLength + charWidth > width) {
					// Need to wrap - close current line with reset if needed
					if (activeAnsiCodes.length > 0) {
						wrapped.push(currentLine + "\x1b[0m");
						// Start new line with active codes
						currentLine = activeAnsiCodes.join("");
					} else {
						wrapped.push(currentLine);
						currentLine = "";
					}
					currentLength = 0;
				}

				currentLine += char;
				currentLength += charWidth;
				i += charByteLength;
			}
		}

		if (currentLine) {
			wrapped.push(currentLine);
		}

		return wrapped.length > 0 ? wrapped : [""];
	}

	/**
	 * Render a list with proper nesting support
	 */
	private renderList(token: Token & { items: any[]; ordered: boolean }, depth: number): string[] {
		const lines: string[] = [];
		const indent = "  ".repeat(depth);

		for (let i = 0; i < token.items.length; i++) {
			const item = token.items[i];
			const bullet = token.ordered ? `${i + 1}. ` : "- ";

			// Process item tokens to handle nested lists
			const itemLines = this.renderListItem(item.tokens || [], depth);

			if (itemLines.length > 0) {
				// First line - check if it's a nested list (contains cyan ANSI code for bullets)
				const firstLine = itemLines[0];
				const isNestedList = firstLine.includes("\x1b[36m"); // cyan color code

				if (isNestedList) {
					// This is a nested list, just add it as-is (already has full indent)
					lines.push(firstLine);
				} else {
					// Regular text content - add indent and bullet
					lines.push(indent + chalk.cyan(bullet) + firstLine);
				}

				// Rest of the lines
				for (let j = 1; j < itemLines.length; j++) {
					const line = itemLines[j];
					const isNestedListLine = line.includes("\x1b[36m"); // cyan bullet color

					if (isNestedListLine) {
						// Nested list line - already has full indent
						lines.push(line);
					} else {
						// Regular content - add parent indent + 2 spaces for continuation
						lines.push(indent + "  " + line);
					}
				}
			} else {
				lines.push(indent + chalk.cyan(bullet));
			}
		}

		return lines;
	}

	/**
	 * Render list item tokens, handling nested lists
	 * Returns lines WITHOUT the parent indent (renderList will add it)
	 */
	private renderListItem(tokens: Token[], parentDepth: number): string[] {
		const lines: string[] = [];

		for (const token of tokens) {
			if (token.type === "list") {
				// Nested list - render with one additional indent level
				// These lines will have their own indent, so we just add them as-is
				const nestedLines = this.renderList(token as any, parentDepth + 1);
				lines.push(...nestedLines);
			} else if (token.type === "text") {
				// Text content (may have inline tokens)
				const text =
					token.tokens && token.tokens.length > 0 ? this.renderInlineTokens(token.tokens) : token.text || "";
				lines.push(text);
			} else if (token.type === "paragraph") {
				// Paragraph in list item
				const text = this.renderInlineTokens(token.tokens || []);
				lines.push(text);
			} else if (token.type === "code") {
				// Code block in list item
				lines.push(chalk.gray("```" + (token.lang || "")));
				const codeLines = token.text.split("\n");
				for (const codeLine of codeLines) {
					lines.push(chalk.dim("  ") + chalk.green(codeLine));
				}
				lines.push(chalk.gray("```"));
			} else {
				// Other token types - try to render as inline
				const text = this.renderInlineTokens([token]);
				if (text) {
					lines.push(text);
				}
			}
		}

		return lines;
	}

	/**
	 * Render a table
	 */
	private renderTable(token: Token & { header: any[]; rows: any[][] }): string[] {
		const lines: string[] = [];

		// Calculate column widths
		const columnWidths: number[] = [];

		// Check header
		for (let i = 0; i < token.header.length; i++) {
			const headerText = this.renderInlineTokens(token.header[i].tokens || []);
			const width = visibleWidth(headerText);
			columnWidths[i] = Math.max(columnWidths[i] || 0, width);
		}

		// Check rows
		for (const row of token.rows) {
			for (let i = 0; i < row.length; i++) {
				const cellText = this.renderInlineTokens(row[i].tokens || []);
				const width = visibleWidth(cellText);
				columnWidths[i] = Math.max(columnWidths[i] || 0, width);
			}
		}

		// Limit column widths to reasonable max
		const maxColWidth = 40;
		for (let i = 0; i < columnWidths.length; i++) {
			columnWidths[i] = Math.min(columnWidths[i], maxColWidth);
		}

		// Render header
		const headerCells = token.header.map((cell, i) => {
			const text = this.renderInlineTokens(cell.tokens || []);
			return chalk.bold(text.padEnd(columnWidths[i]));
		});
		lines.push("│ " + headerCells.join(" │ ") + " │");

		// Render separator
		const separatorCells = columnWidths.map((width) => "─".repeat(width));
		lines.push("├─" + separatorCells.join("─┼─") + "─┤");

		// Render rows
		for (const row of token.rows) {
			const rowCells = row.map((cell, i) => {
				const text = this.renderInlineTokens(cell.tokens || []);
				const visWidth = visibleWidth(text);
				const padding = " ".repeat(Math.max(0, columnWidths[i] - visWidth));
				return text + padding;
			});
			lines.push("│ " + rowCells.join(" │ ") + " │");
		}

		lines.push(""); // Add spacing after table
		return lines;
	}
}