var rules = require("../lib/rules");
var bottomUp = require("../lib/bottom-up");
var testing = require("../lib/testing");
var TokenIterator = require("../lib/TokenIterator");
var errors = require("../lib/errors");
var results = require("../lib/parsing-results");
var StringSource = require("../lib/StringSource");
var assertIsSuccess = testing.assertIsSuccess;
var assertIsSuccessWithValue = testing.assertIsSuccessWithValue;
var assertIsFailure = testing.assertIsFailure;
var assertIsFailureWithRemaining = testing.assertIsFailureWithRemaining;
var assertIsError = testing.assertIsError;
var Tokeniser = require("./Tokeniser");
var Token = require("../lib/Token");

var source = function(string, startIndex, endIndex) {
    return new StringSource(string).range(startIndex, endIndex);
};

var token = function(tokenType, value, source) {
    return new Token(tokenType, value, source);
};

var partialCallRule = bottomUp.infix("call", function(parser) {
    return rules.sequence(
        rules.token("symbol", "("),
        rules.sequence.capture(parser.rule()),
        rules.token("symbol", ")")
    ).head();
}).map(function(left, arg) {
    return [left, arg];
});

var partialAddRule = bottomUp.infix("add", function(parser) {
    return rules.sequence(
        rules.token("symbol", "+"),
        rules.sequence.capture(parser.leftAssociative("add"))
    ).head();
}).map(function(left, right) {
    return ["+", left, right];
});

var partialMultiplyRule = bottomUp.infix("multiply", function(parser) {
    return rules.sequence(
        rules.token("symbol", "*"),
        rules.sequence.capture(parser.leftAssociative("multiply"))
    ).head();
}).map(function(left, right) {
    return ["*", left, right];
});
    
var partialPowerRule = bottomUp.infix("power", function(parser) {
    return rules.sequence(
        rules.token("symbol", "^"),
        rules.sequence.capture(parser.rightAssociative("power"))
    ).head();
}).map(function(left, right) {
    return ["^", left, right];
});

exports.canParsePrefixExpression = function(test) {
    var rule = bottomUp.parser("expression",
        [rules.tokenOfType("identifier")],
        []
    ).rule();
    var result = parse(rule, [
        token("identifier", "blah", source("blah", 0, 4)),
        token("end", null, source("blah", 4, 4))
    ]);
    assertIsSuccess(test, result, {
        value: "blah",
        source: source("blah", 0, 4)
    });
    test.done();
};

exports.canParseSimpleInfixExpression = function(test) {
    var rule = bottomUp.parser("expression",
        [rules.tokenOfType("identifier")],
        [partialCallRule]
    ).rule();
    
    var result = parse(rule, [
        token("identifier", "print", source("print(name)", 0, 5)),
        token("symbol", "(", source("print(name)", 5, 6)),
        token("identifier", "name", source("print(name)", 6, 10)),
        token("symbol", ")", source("print(name)", 10, 11)),
        token("end", null, source("print(name)", 11, 11))
    ]);
    assertIsSuccess(test, result, {
        value: ["print", "name"],
        source: source("print(name)", 0, 11)
    });
    test.done();
};

exports.parsingStopsIfPrefixRuleFails = function(test) {
    var rule = bottomUp.parser("expression",
        [rules.tokenOfType("identifier")],
        [partialCallRule]
    ).rule();
    
    var result = parse(rule, [
        token("symbol", "(", source("(name)", 0, 1)),
        token("identifier", "name", source("(name)", 1, 5)),
        token("symbol", ")", source("(name)", 5, 6)),
        token("end", null, source("(name)", 6, 6))
    ]);
    assertIsFailure(test, result, {
        remaining: [
            token("symbol", "(", source("(name)", 0, 1)),
            token("identifier", "name", source("(name)", 1, 5)),
            token("symbol", ")", source("(name)", 5, 6)),
            token("end", null, source("(name)", 6, 6))
        ],
        errors: [errors.error({
            expected: "expression",
            actual: "symbol \"(\"",
            location: source("(name)", 0, 1)
        })]
    });
    test.done();
};

exports.canParseExpressionWithTwoLeftAssociativeOperators = function(test) {
    var expressionParser = bottomUp.parser("expression",
        [rules.tokenOfType("number")],
        [
            partialMultiplyRule,
            partialAddRule
        ]
    );
    
    var rule = expressionParser.rule();
    
    var result = parse(rule, [
        token("number", "1", source("1 * 2 * 3 + 4 * 5", 0, 1)),
        token("symbol", "*", source("1 * 2 * 3 + 4 * 5", 2, 3)),
        token("number", "2", source("1 * 2 * 3 + 4 * 5", 4, 5)),
        token("symbol", "*", source("1 * 2 * 3 + 4 * 5", 6, 7)),
        token("number", "3", source("1 * 2 * 3 + 4 * 5", 8, 9)),
        token("symbol", "+", source("1 * 2 * 3 + 4 * 5", 10, 11)),
        token("number", "4", source("1 * 2 * 3 + 4 * 5", 12, 13)),
        token("symbol", "*", source("1 * 2 * 3 + 4 * 5", 14, 15)),
        token("number", "5", source("1 * 2 * 3 + 4 * 5", 16, 17)),
        token("end", null, source("1 * 2 * 3 + 4 * 5", 17, 17))
    ]);
    assertIsSuccess(test, result, {
        value: ["+", ["*", ["*", "1", "2"], "3"], ["*", "4", "5"]],
        source: source("1 * 2 * 3 + 4 * 5", 0, 17)
    });
    test.done();
};

exports.canParseExpressionWithRightAssociativeOperators = function(test) {
    var expressionParser = bottomUp.parser("expression",
        [rules.tokenOfType("number")],
        [
            partialPowerRule,
            partialAddRule
        ]
    );
    
    var rule = expressionParser.rule();
    
    var result = parse(rule, [
        token("number", "1", source("1 ^ 2 ^ 3 + 4 ^ 5", 0, 1)),
        token("symbol", "^", source("1 ^ 2 ^ 3 + 4 ^ 5", 2, 3)),
        token("number", "2", source("1 ^ 2 ^ 3 + 4 ^ 5", 4, 5)),
        token("symbol", "^", source("1 ^ 2 ^ 3 + 4 ^ 5", 6, 7)),
        token("number", "3", source("1 ^ 2 ^ 3 + 4 ^ 5", 8, 9)),
        token("symbol", "+", source("1 ^ 2 ^ 3 + 4 ^ 5", 10, 11)),
        token("number", "4", source("1 ^ 2 ^ 3 + 4 ^ 5", 12, 13)),
        token("symbol", "^", source("1 ^ 2 ^ 3 + 4 ^ 5", 14, 15)),
        token("number", "5", source("1 ^ 2 ^ 3 + 4 ^ 5", 16, 17)),
        token("end", null, source("1 ^ 2 ^ 3 + 4 ^ 5", 17, 17))
    ]);
    assertIsSuccess(test, result, {
        value: ["+", ["^", "1", ["^", "2", "3"]], ["^", "4", "5"]],
        source: source("1 ^ 2 ^ 3 + 4 ^ 5", 0, 17)
    });
    test.done();
};

var parse = function(parser, tokens) {
    return parser(new TokenIterator(tokens));
};