'use strict';

const pad = require("pad");
const chalk = Object.assign(require("chalk"), {enabled: true});
const defaultValue = require("default-value");

module.exports = function createBetterPegTracer(parsedString) {
	let currentLevel = 0;
	let lastWasFail = false
	let parsedStringLines = parsedString.split("\n");
	let lastSeenRule = [];

	return {
		trace: function trace(event) {
			if (event.type === "rule.fail" || event.type === "rule.match") {
				currentLevel -= 1;
			}

			let ruleIndent = pad("", currentLevel * 4);
			let eventName = event.type.replace(/^rule\./, "");
			let isMultiline = (parsedStringLines.length > 1);

			let startLine = event.location.start.line;
			let endLine = event.location.end.line;
			let startColumn = event.location.start.column;
			let endColumn = event.location.end.column;

			let firstLine = parsedStringLines[startLine - 1];
			let lastLine = parsedStringLines[endLine - 1];

			let affectedString, color, startPosition, endPosition, position;

			if (isMultiline) {
				startPosition = `${pad(4, startLine)}:${pad(2, startColumn)}`;

				if (startLine !== endLine || startColumn !== endColumn) {
					endPosition = `${pad(4, endLine)}:${pad(2, endColumn)}`;
				}
			} else {
				startPosition = startColumn;

				if (startColumn !== endColumn) {
					endPosition = endColumn;
				}
			}

			position = `${pad(8, startPosition)}  ${chalk.white("│")} ${pad(8, defaultValue(endPosition, ""))}`;

			if (startLine === endLine) {
				if (startColumn === endColumn) {
					/* Not reading a range, but rather attempting to find a match from the current point. */
					if (event.location.start.offset < parsedString.length) {
						affectedString = chalk.gray(`${firstLine.slice(startColumn - 1)}  ...`);
					} else {
						affectedString = "";
					}
				} else {
					affectedString = firstLine.slice(startColumn - 1, endColumn - 1);
				}
			} else {
				affectedString = `${firstLine.slice(startColumn - 1)}   ...   ${lastLine.slice(0, endColumn - 1)}`;
			}

			if (event.type === "rule.enter") {
				lastSeenRule[currentLevel] = event.rule;
			}

			if (event.type === "rule.match") {
				color = chalk.green;
			} else if (event.type === "rule.fail") {
				color = chalk.red;
			} else {
				color = chalk.white;
			}

			let crumbs = lastSeenRule.slice(0, currentLevel).concat([color(event.rule)]);
			let limitedCrumbs;

			if (crumbs.length > 6) {
				limitedCrumbs = crumbs.slice(0, 2).concat([`... ${crumbs.length - 5} hidden ...`]).concat(crumbs.slice(-3));
			} else {
				limitedCrumbs = crumbs;
			}

			let line = [
				position,
				pad(eventName, 5),
				chalk.gray(pad(limitedCrumbs.join(" -> "), "90")),
				affectedString
			].join(` ${chalk.white("│")} `);

			process.stdout.write(color(line + "\n"));

			if (event.type === "rule.enter") {
				currentLevel += 1;
			}
		}
	}
}