import { CharacterStream, LiteralToken, ParseException, Token, TokenStream, TokenType } from './index.js'

const regexpToken = (stream, tokens) => {
	if (tokens.length > 0) {
		let token = tokens[tokens.length - 1];
		if (token instanceof LiteralToken) {
			return false;
		}
		switch (token.getTokenType()) {
			case TokenType.Comma:			// ,
			case TokenType.Semicolon:		// ;
			case TokenType.Colon:			// :
			case TokenType.RightCurly:		// }
			case TokenType.LeftBracket:		// [
			case TokenType.LeftParantheses:	// (
			case TokenType.Assignment:		// =
			case TokenType.NotEqual:		// !=
			case TokenType.EqualEqualEqual:	// ===
			case TokenType.NotEqualEqual:	// !==
			case TokenType.Equal:			// ==
			case TokenType.And:				// &&
			case TokenType.Or:				// ||
			case TokenType.SqlAnd:			// and
			case TokenType.SqlOr:			// or
			case TokenType.SqlNotEqual:		// <>
			case TokenType.Questionmark:	// ?
			case TokenType.InstanceOf:      // instanceof
			case TokenType.Lambda:			// => ->
			case TokenType.Not:				// !
				break;
			default: return false;
		}
	}
	if (stream.match("/", false)) {
		let mark = stream.getPosition();
		stream.consume();
		stream.startSpan();
		let matchedEndQuote = false;
		let deep = 0;
		let maybeMissForwardSlash = 0;
		let maybeMissForwardSlashEnd = 0;
		while (stream.hasMore()) {
			// Note: escape sequences like \n are parsed in StringLiteral
			if (stream.match("\\", true)) {
				stream.consume();
				continue;
			}
			if (stream.match("[", false)) {
				deep++;
				maybeMissForwardSlash = stream.getPosition();
			} else if (deep > 0 && stream.match("]", false)) {
				deep--;
			} else if (stream.match(TokenType.ForwardSlash.literal, true)) {
				if (deep === 0) {
					if (stream.match("g", true)) {
					}
					if (stream.match("i", true)) {
					}
					if (stream.match("m", true)) {
					}
					if (stream.match("s", true)) {
					}
					if (stream.match("u", true)) {
					}
					if (stream.match("y", true)) {
					}
					matchedEndQuote = true;
					break;
				} else {
					maybeMissForwardSlashEnd = stream.getPosition();
				}
			}
			let ch = stream.consume();
			if (ch === '\r' || ch === '\n') {
				stream.reset(mark);
				return false;
			}
		}
		if (deep !== 0) {
			throw new ParseException("Missing ']'", stream.getSpan(maybeMissForwardSlash, maybeMissForwardSlashEnd - 1));
		}
		if (!matchedEndQuote) {
			stream.reset(mark);
			return false;
		}
		let regexpSpan = stream.endSpan();
		regexpSpan = stream.getSpan(regexpSpan.getStart() - 1, regexpSpan.getEnd());
		tokens.push(new LiteralToken(TokenType.RegexpLiteral, regexpSpan));
		return true;
	}
	return false;
}

const tokenizerString = (stream, tokenType, tokens) => {
	// String literal
	if (stream.match(tokenType, true)) {
		stream.startSpan();
		let matchedEndQuote = false;
		while (stream.hasMore()) {
			// Note: escape sequences like \n are parsed in StringLiteral
			if (stream.match("\\", true)) {
				stream.consume();
				continue;
			}
			if (stream.match(tokenType.literal, true)) {
				matchedEndQuote = true;
				break;
			}
			let ch = stream.consume();
			if (tokenType !== TokenType.TripleQuote && (ch === '\r' || ch === '\n')) {
				throw new ParseException(tokenType.error + tokenType.error + "定义的字符串不能换行", stream.endSpan());
			}
		}
		if (!matchedEndQuote) {
			throw new ParseException("字符串没有结束符" + tokenType.error, stream.endSpan());
		}
		let stringSpan = stream.endSpan();
		stringSpan = stream.getSpan(stringSpan.getStart(), stringSpan.getEnd() - tokenType.literal.length);
		tokens.push(new LiteralToken(TokenType.StringLiteral, stringSpan));
		return true;
	}
	return false;
};
const autoNumberType = (span, radix) => {
	let value = Number.parseInt(span.getText().substring(2).replace(/\_/g, ''), radix)
	if (value > 0x7fffffff || value < -0x80000000) {
		return new LiteralToken(TokenType.LongLiteral, span, value);
	} else if (value > 127 || value < -128) {
		return new LiteralToken(TokenType.IntegerLiteral, span, value);
	}
	return new LiteralToken(TokenType.ByteLiteral, span, value);
}
const tokenizerNumber = (stream, tokens) => {
	if (stream.match('0', false)) {
		let index = stream.getPosition();
		stream.startSpan();
		stream.consume();
		if (stream.matchAny(['x', 'X'], true)) {
			while (stream.matchDigit(true) || stream.matchAny(["A", "B", "C", "D", "E", "F", "a", "b", "c", "d", "e", "f", "_"], true)) {
				;
			}
			if (stream.matchAny(["L", "l"], true)) {
				let span = stream.endSpan();
				let text = span.getText();
				tokens.push(new LiteralToken(TokenType.LongLiteral, span, parseInt(text.substring(2, text.length - 1).replace(/\_/g, ''), 16)));
				return true;
			}
			tokens.push(autoNumberType(stream.endSpan(), 16));
			return true;
		} else if (stream.matchAny(['b', 'B'], true)) {
			while (stream.matchAny(['0', '1', '_'], true)) {
				;
			}
			if (stream.matchAny(["L", "l"], true)) {
				let span = stream.endSpan();
				let text = span.getText();
				tokens.push(new LiteralToken(TokenType.LongLiteral, span, parseInt(text.substring(2, text.length - 1).replace(/\_/g, ''), 2)));
				return true;
			}
			tokens.push(autoNumberType(stream.endSpan(), 2));
			return true;
		}
		stream.reset(index);
	}
	if (stream.matchDigit(false)) {
		let type = TokenType.IntegerLiteral;
		stream.startSpan();
		while (stream.matchDigit(true) || stream.match('_', true)) {
		}
		if (stream.match(TokenType.Period.literal, true)) {
			if (stream.hasMore()) {
				type = TokenType.DoubleLiteral;
				while (stream.matchDigit(true) || stream.match('_', true)) {
				}
			} else {
				stream.reset(stream.getPosition() - 1)
			}
		}
		if (stream.matchAny(['b', 'B'], true)) {
			if (type === TokenType.DoubleLiteral) {
				throw new ParseException('Byte literal can not have a decimal point.', stream.endSpan());
			}
			type = TokenType.ByteLiteral;
		} else if (stream.matchAny(['s', 'S'], true)) {
			if (type === TokenType.DoubleLiteral) {
				throw new ParseException('Short literal can not have a decimal point.', stream.endSpan());
			}
			type = TokenType.ShortLiteral;
		} else if (stream.matchAny(['l', 'L'], true)) {
			if (type === TokenType.DoubleLiteral) {
				throw new ParseException('Long literal can not have a decimal point.', stream.endSpan());
			}
			type = TokenType.LongLiteral;
		} else if (stream.matchAny(['f', 'F'], true)) {
			type = TokenType.FloatLiteral;
		} else if (stream.matchAny(['d', 'D'], true)) {
			type = TokenType.DoubleLiteral;
		} else if (stream.matchAny(['m', 'M'], true)) {
			type = TokenType.DecimalLiteral;
		}
		tokens.push(new LiteralToken(type, stream.endSpan()));
		return true
	}
	return false;
}

const tokenizerLanguage = (stream, tokens) => {
	if (stream.match("```", true)) {
		stream.startSpan();
		if (stream.matchIdentifierStart(true)) {
			while (stream.matchIdentifierPart(true)) {
			}
			let language = stream.endSpan();
			tokens.push(new Token(TokenType.Language, language));
			stream.startSpan();
			if (!stream.skipUntil("```")) {
				throw new ParseException('```需要以```结尾', stream.endSpan());
			}
			tokens.push(new Token(TokenType.Language, stream.endSpan(-3)));
			return true;
		} else {
			throw new ParseException('```后需要标识语言类型', stream.endSpan());
		}
	}
	return false;
}
const tokenizerIdentifier = (stream, tokens) => {
	if (stream.matchIdentifierStart(true)) {
		stream.startSpan();
		while (stream.matchIdentifierPart(true)) {
		}
		let identifierSpan = stream.endSpan();
		identifierSpan = stream.getSpan(identifierSpan.getStart() - 1, identifierSpan.getEnd());
		if ("true" === identifierSpan.getText() || "false" === identifierSpan.getText()) {
			tokens.push(new LiteralToken(TokenType.BooleanLiteral, identifierSpan));
		} else if ("null" === identifierSpan.getText()) {
			tokens.push(new LiteralToken(TokenType.NullLiteral, identifierSpan));
		} else if (TokenType.SqlAnd.literal.toUpperCase() === identifierSpan.getText().toUpperCase()) {
			tokens.push(new Token(TokenType.SqlAnd, identifierSpan));
		} else if (TokenType.SqlOr.literal.toUpperCase() === identifierSpan.getText().toUpperCase()) {
			tokens.push(new Token(TokenType.SqlOr, identifierSpan));
		} else {
			tokens.push(new Token(TokenType.Identifier, identifierSpan));
		}
		return true;
	}
	return false;
}

const tokenizerTemplateString = (stream, tokens) => {
	if (stream.match("`", true)) {
		let begin = stream.getPosition();
		let start = begin;
		let matchedEndQuote = false;
		let subTokens = [];
		while (stream.hasMore()) {
			if (stream.match("\\", true)) {
				stream.consume();
				continue;
			}
			if (stream.match("`", true)) {
				matchedEndQuote = true;
				break;
			}
			if (stream.match("${", true)) {
				let end = stream.getPosition();
				if (start < end - 2) {
					subTokens.push(new LiteralToken(TokenType.StringLiteral, stream.endSpan(start, end - 2)));
				}
				subTokens.push(...tokenizer(stream, [], "}"));
				start = stream.getPosition();
				continue;
			}
			stream.consume();
		}
		let stringSpan = stream.endSpan(begin, stream.getPosition());
		let end = stream.getPosition() - 1;
		if (end - start > 0) {
			subTokens.push(new LiteralToken(TokenType.StringLiteral, stream.endSpan(start, end)));
		}
		stringSpan = stream.getSpan(stringSpan.getStart() - 1, stringSpan.getEnd());
		tokens.push(new LiteralToken(TokenType.StringLiteral, stringSpan, new TokenStream(subTokens)));
		return true;
	}
	return false;
}

const tokenizer = (stream, tokens, except) => {
	let leftCount = 0;
	let rightCount = 0;
	while (stream.hasMore()) {
		stream.skipWhiteSpace();
		if (except && stream.match(except, true)) {
			return tokens;
		}
		if (stream.match("//", true)) {	//注释
			stream.skipLine();
			continue;
		}
		if (stream.match("/*", true)) {	//多行注释
			stream.skipUntil("*/");
			continue;
		}
		// int short double long float byte decimal
		if (tokenizerNumber(stream, tokens)) {
			continue;
		}
		// '' "" """ """
		if (tokenizerString(stream, TokenType.SingleQuote, tokens) || tokenizerString(stream, TokenType.TripleQuote, tokens) || tokenizerString(stream, TokenType.DoubleQuote, tokens)) {
			continue;
		}

		// regexp
		if (regexpToken(stream, tokens)) {
			continue;
		}
		// ``` ```
		if (tokenizerLanguage(stream, tokens)) {
			continue;
		}
		// template string
		if (tokenizerTemplateString(stream, tokens)) {
			continue;
		}

		// Identifier, keyword, boolean literal, or null literal
		if (tokenizerIdentifier(stream, tokens)) {
			continue;
		}
		// lambda
		if (stream.matchAny(['=>', '->'], true)) {
			tokens.push(new Token(TokenType.Lambda, stream.getSpan(stream.getPosition() - 2, stream.getPosition())));
			continue;
		}
		let outer = false;
		// Simple tokens
		let sortedTokens = TokenType.getSortedValues();
		for (let i = 0, len = sortedTokens.length; i < len; i++) {
			let t = sortedTokens[i];
			if (t.literal != null) {
				if (stream.match(t.literal, true)) {
					if (t === TokenType.LeftCurly) {
						leftCount++;
					}
					tokens.push(new Token(t, stream.getSpan(stream.getPosition() - t.literal.length, stream.getPosition())));
					outer = true;
					break;
				}
			}
		}
		if (outer) {
			continue;
		}
		if (leftCount !== rightCount && stream.match("}", true)) {
			rightCount++;
			tokens.push(new Token(TokenType.RightCurly, stream.getSpan(stream.getPosition() - 1, stream.getPosition())));
			continue;
		}
		if (stream.hasMore()) {
			throw new ParseException("Unknown token", stream.getSpan(stream.getPosition(), stream.getPosition() + 1));
		}
	}
	return tokens;
}

export default (source) => {
	return tokenizer(new CharacterStream(source, 0, source.length), [])
}