#include "parser.h"
#include "SolsNode.h"

#include "../include/estr.h"
#include "../include/ansii.h"
#include <groundvm.h>

SolsTokenPrecedence getPrecedence(SolsToken *token) {
    switch (token->type) {
        case STT_LINE_END: return STP_NEWLINE;
        case STT_KW_PUTS: return STP_PUTS;
        case STT_OP_ADDTO:
        case STT_OP_SUBTO:
        case STT_OP_MULTO:
        case STT_OP_DIVTO:
        case STT_OP_INCREMENT:
        case STT_OP_DECREMENT:
        case STT_OP_SET: return STP_SET;
        // FIXME figure out how to do functions
        case STT_OP_MUL: case STT_OP_DIV: return STP_MUL;
        case STT_OP_ADD: case STT_OP_SUB: return STP_ADD;
        case STT_OP_EQUAL:
        case STT_OP_EQGREATER:
        case STT_OP_EQLESSER:
        case STT_OP_INEQUAL:
        case STT_OP_GREATER:
        case STT_OP_LESSER: return STP_COMPARE;
        default: return STP_OTHER;
    }
}

ResultType(SolsParser, charptr) createSolsParser(SolsTokens* input) {
    ResultType(SolsNode, charptr) node = createSolsNode(SNT_ROOT);
    if (node.error) {
        Estr str = CREATE_ESTR(node.as.error);
        APPEND_ESTR(str, " (in createSolsParser() function)");
        return Error(SolsParser, charptr, str.str);
    }
    SolsParser parser = {
        .input = input,
        .current = 0,
        .output = node.as.success,
        .errors.capacity = 32,
        .errors.count = 0,
        .errors.at = malloc(sizeof(char*) * 32)
    };
    if (parser.errors.at == NULL) {
        return Error(SolsParser, charptr, "Couldn't allocate memory to store errors (in createSolsParser() function)");
    }
    return Success(SolsParser, charptr, parser);
}

void addToParserErrors(SolsParser* parser, char* errors) {
    if (parser->errors.count + 1 >= parser->errors.capacity) {
        parser->errors.capacity *= 2;
        char** tmp = realloc(parser->errors.at, sizeof(char*) * parser->errors.capacity);
        if (tmp == NULL) {
            parser->errors.at[parser->errors.count - 1] = "Failed to allocate more memory for addToParserErrors function";
            return;
        }
        parser->errors.at = tmp;
    }
    parser->errors.at[parser->errors.count] = errors;
    parser->errors.count++;
}

void createParserError(SolsParser* parser, char* what) {

    ResultType(SolsToken, Nothing) prevToken = Error(SolsToken, Nothing, {});
    SolsToken token = parserPeek(parser, 0).as.success;
    ResultType(SolsToken, Nothing) nextToken = Error(SolsToken, Nothing, {});

    // Find tokens for previous line
    if (parser->current > 1) {
        for (size_t i = parser->current - 1; i > 0; i--) {
            ResultType(SolsToken, Nothing) check = parserLookAt(parser, i - 1);
            if (check.error) break;
            if (check.as.success.line.num != token.line.num) {
                prevToken = check;
                break;
            }
        }
    }

    // Find tokens for next line
    for (size_t i = parser->current; i < parser->input->count; i++) {
        ResultType(SolsToken, Nothing) check = parserLookAt(parser, i);
        if (check.error) break;
        if (check.as.success.line.num != token.line.num) {
            nextToken = check;
            break;
        }
    }

    if (parser->errors.count + 1 >= parser->errors.capacity) {
        parser->errors.capacity *= 2;
        char** tmp = realloc(parser->errors.at, sizeof(char*) * parser->errors.capacity);
        if (tmp == NULL) {
            parser->errors.at[parser->errors.count - 1] = "Failed to allocate more memory for createParserError function";
            return;
        }
        parser->errors.at = tmp;
    }
    Estr err = CREATE_ESTR(ESC_BOLD ESC_RED_FG "error: " ESC_RESET ESC_BOLD);
    
    // Append the main error message and a newline
    APPEND_ESTR(err, what);
    APPEND_ESTR(err, "\n" ESC_RESET);

    APPEND_ESTR(err, ESC_CYAN_FG "-> " ESC_RESET);
    APPEND_ESTR(err, "on line ");
    
    // Format the line number
    char line_buf[16];
    snprintf(line_buf, sizeof(line_buf), "%zu", token.line.num);
    APPEND_ESTR(err, line_buf);

    APPEND_ESTR(err, "\n\n");
    // Append line before
    if (!prevToken.error) {
        APPEND_ESTR(err, prevToken.as.success.line.content);
        APPEND_ESTR(err, "\n");
    }
    // Append the actual content of the line that failed
    APPEND_ESTR(err, token.line.content);
    APPEND_ESTR(err, "\n");
    if (!nextToken.error) {
        APPEND_ESTR(err, nextToken.as.success.line.content);
        APPEND_ESTR(err, "\n");
    }

    // Output the final constructed error
    parser->errors.at[parser->errors.count] = err.str;
    parser->errors.count++;
}

static inline ResultType(Nothing, charptr) parseIdentifier(SolsParser* parser) {
    ResultType(SolsToken, Nothing) peek = parserPeek(parser, 0);
    if (peek.error) {
        return Error(Nothing, charptr, "ruh roh");
    }
    ResultType(SolsNode, charptr) node = createSolsNode(SNT_IDENTIFIER, peek.as.success.as.idName);
    if (node.error) {
        Estr err = CREATE_ESTR(node.as.error);
        APPEND_ESTR(err, " (in parseLiteral() function)");
        return Error(Nothing, charptr, err.str);
    }
    node.as.success.line = peek.as.success.line;
    node.as.success.accessArg = (GroundArg) {
        .type = VALREF,
        .value.refName = peek.as.success.as.idName
    };
    addChildToSolsNode(parser->currentParent, node.as.success);
    return Success(Nothing, charptr, {});
}

static inline ResultType(Nothing, charptr) parseSet(SolsParser* parser) {
    if (parser->currentParent->children.count < 1) {
        return Error(Nothing, charptr, "Expecting identifier before '='");
    }
    if (parser->currentParent->children.at[parser->output.children.count - 1].type != SNT_IDENTIFIER) {
        return Error(Nothing, charptr, "Expecting identifier before '='");
    }
    
    // Collect tokens for node
    ResultType(SolsTokens, charptr) tokens = createSolsTokens();
    if (tokens.error) {
        return Error(Nothing, charptr, tokens.as.error);
    }

    // Get the identifier (previous node)
    SolsNode idNode = parser->currentParent->children.at[parser->currentParent->children.count - 1];

    ResultType(SolsToken, Nothing) peek = parserPeek(parser, 0);
    if (peek.error) return Error(Nothing, charptr, "ruh roh");

    for (;;) {
        ResultType(SolsToken, Nothing) peek = parserPeek(parser, 1);
        if (peek.error) break;
        if (getPrecedence(&peek.as.success) <= STP_SET) {
            break;
        }
        parserConsume(parser);
        addTokenToSolsTokens(&tokens.as.success, peek.as.success);
    }

    // Create node
    ResultType(SolsNode, charptr) node = createSolsNode(SNT_OP_SET);
    if (node.error) return Error(Nothing, charptr, node.as.error);
    node.as.success.line = peek.as.success.line;

    // Parse selected tokens
    ResultType(SolsParser, charptr) putsParser = createSolsParser(&tokens.as.success);
    if (putsParser.error) return Error(Nothing, charptr, putsParser.as.error);
    putsParser.as.success.currentParent = &putsParser.as.success.output;
    ResultType(Nothing, charptr) parsed = parse(&putsParser.as.success);

    // Add any error messages from parsing
    if (parsed.error) {
        addToParserErrors(parser, parsed.as.error);
        return Success(Nothing, charptr, {});
    }

    if (putsParser.as.success.output.children.count < 1) {
        return Error(Nothing, charptr, "Expecting token after '='");
    }

    // Copy idnode into set node
    addChildToSolsNode(&node.as.success, idNode);

    // Copy nodes into the set node
    for (size_t i = 0; i < putsParser.as.success.output.children.count; i++) {
        addChildToSolsNode(&node.as.success, putsParser.as.success.output.children.at[i]);
    }

    // Put the set node where the idNode was
    parser->currentParent->children.count--;
    addChildToSolsNode(parser->currentParent, node.as.success);

    return Success(Nothing, charptr, {});
}

static inline ResultType(Nothing, charptr) parseAdd(SolsParser* parser) {
    if (parser->currentParent->children.count < 1) {
        return Error(Nothing, charptr, "Expecting something before '+'");
    }

    // Collect tokens for node
    ResultType(SolsTokens, charptr) tokens = createSolsTokens();
    if (tokens.error) {
        return Error(Nothing, charptr, tokens.as.error);
    }

    // Get the previous node
    SolsNode idNode = parser->currentParent->children.at[parser->currentParent->children.count - 1];

    ResultType(SolsToken, Nothing) peek = parserPeek(parser, 0);
    if (peek.error) return Error(Nothing, charptr, "ruh roh");

    for (;;) {
        ResultType(SolsToken, Nothing) peek = parserPeek(parser, 1);
        if (peek.error) break;
        if (getPrecedence(&peek.as.success) <= STP_ADD) {
            break;
        }
        parserConsume(parser);
        addTokenToSolsTokens(&tokens.as.success, peek.as.success);
    }

    // Create node
    ResultType(SolsNode, charptr) node = createSolsNode(SNT_OP_ADD);
    if (node.error) return Error(Nothing, charptr, node.as.error);
    node.as.success.line = peek.as.success.line;

    // Parse selected tokens
    ResultType(SolsParser, charptr) putsParser = createSolsParser(&tokens.as.success);
    if (putsParser.error) return Error(Nothing, charptr, putsParser.as.error);
    putsParser.as.success.currentParent = &putsParser.as.success.output;
    ResultType(Nothing, charptr) parsed = parse(&putsParser.as.success);

    // Add any error messages from parsing
    if (parsed.error) {
        addToParserErrors(parser, parsed.as.error);
        return Success(Nothing, charptr, {});
    }

    if (putsParser.as.success.output.children.count < 1) {
        return Error(Nothing, charptr, "Expecting token after '+'");
    }

    // Copy idnode into set node
    addChildToSolsNode(&node.as.success, idNode);

    // Copy nodes into the set node
    for (size_t i = 0; i < putsParser.as.success.output.children.count; i++) {
        addChildToSolsNode(&node.as.success, putsParser.as.success.output.children.at[i]);
    }

    // Put the set node where the idNode was
    parser->currentParent->children.count--;
    addChildToSolsNode(parser->currentParent, node.as.success);

    return Success(Nothing, charptr, {});
}

static inline ResultType(Nothing, charptr) parseSub(SolsParser* parser) {
    if (parser->currentParent->children.count < 1) {
        return Error(Nothing, charptr, "Expecting something before '-'");
    }

    // Collect tokens for node
    ResultType(SolsTokens, charptr) tokens = createSolsTokens();
    if (tokens.error) {
        return Error(Nothing, charptr, tokens.as.error);
    }

    // Get the previous node
    SolsNode idNode = parser->currentParent->children.at[parser->currentParent->children.count - 1];

    ResultType(SolsToken, Nothing) peek = parserPeek(parser, 0);
    if (peek.error) return Error(Nothing, charptr, "ruh roh");

    for (;;) {
        ResultType(SolsToken, Nothing) peek = parserPeek(parser, 1);
        if (peek.error) break;
        if (getPrecedence(&peek.as.success) <= STP_ADD) {
            break;
        }
        parserConsume(parser);
        addTokenToSolsTokens(&tokens.as.success, peek.as.success);
    }

    // Create node
    ResultType(SolsNode, charptr) node = createSolsNode(SNT_OP_SUB);
    if (node.error) return Error(Nothing, charptr, node.as.error);
    node.as.success.line = peek.as.success.line;

    // Parse selected tokens
    ResultType(SolsParser, charptr) putsParser = createSolsParser(&tokens.as.success);
    if (putsParser.error) return Error(Nothing, charptr, putsParser.as.error);
    putsParser.as.success.currentParent = &putsParser.as.success.output;
    ResultType(Nothing, charptr) parsed = parse(&putsParser.as.success);

    // Add any error messages from parsing
    if (parsed.error) {
        addToParserErrors(parser, parsed.as.error);
        return Success(Nothing, charptr, {});
    }

    if (putsParser.as.success.output.children.count < 1) {
        return Error(Nothing, charptr, "Expecting token after '-'");
    }

    // Copy idnode into set node
    addChildToSolsNode(&node.as.success, idNode);

    // Copy nodes into the set node
    for (size_t i = 0; i < putsParser.as.success.output.children.count; i++) {
        addChildToSolsNode(&node.as.success, putsParser.as.success.output.children.at[i]);
    }

    // Put the set node where the idNode was
    parser->currentParent->children.count--;
    addChildToSolsNode(parser->currentParent, node.as.success);

    return Success(Nothing, charptr, {});
}

static inline ResultType(Nothing, charptr) parseMul(SolsParser* parser) {
    if (parser->currentParent->children.count < 1) {
        return Error(Nothing, charptr, "Expecting something before '*'");
    }

    // Collect tokens for node
    ResultType(SolsTokens, charptr) tokens = createSolsTokens();
    if (tokens.error) {
        return Error(Nothing, charptr, tokens.as.error);
    }

    // Get the previous node
    SolsNode idNode = parser->currentParent->children.at[parser->currentParent->children.count - 1];

    ResultType(SolsToken, Nothing) peek = parserPeek(parser, 0);
    if (peek.error) return Error(Nothing, charptr, "ruh roh");

    for (;;) {
        ResultType(SolsToken, Nothing) peek = parserPeek(parser, 1);
        if (peek.error) break;
        if (getPrecedence(&peek.as.success) <= STP_MUL) {
            break;
        }
        parserConsume(parser);
        addTokenToSolsTokens(&tokens.as.success, peek.as.success);
    }

    // Create node
    ResultType(SolsNode, charptr) node = createSolsNode(SNT_OP_MUL);
    if (node.error) return Error(Nothing, charptr, node.as.error);
    node.as.success.line = peek.as.success.line;

    // Parse selected tokens
    ResultType(SolsParser, charptr) putsParser = createSolsParser(&tokens.as.success);
    if (putsParser.error) return Error(Nothing, charptr, putsParser.as.error);
    putsParser.as.success.currentParent = &putsParser.as.success.output;
    ResultType(Nothing, charptr) parsed = parse(&putsParser.as.success);

    // Add any error messages from parsing
    if (parsed.error) {
        addToParserErrors(parser, parsed.as.error);
        return Success(Nothing, charptr, {});
    }

    if (putsParser.as.success.output.children.count < 1) {
        return Error(Nothing, charptr, "Expecting token after '*'");
    }

    // Copy idnode into set node
    addChildToSolsNode(&node.as.success, idNode);

    // Copy nodes into the set node
    for (size_t i = 0; i < putsParser.as.success.output.children.count; i++) {
        addChildToSolsNode(&node.as.success, putsParser.as.success.output.children.at[i]);
    }

    // Put the set node where the idNode was
    parser->currentParent->children.count--;
    addChildToSolsNode(parser->currentParent, node.as.success);

    return Success(Nothing, charptr, {});
}

static inline ResultType(Nothing, charptr) parseDiv(SolsParser* parser) {
    if (parser->currentParent->children.count < 1) {
        return Error(Nothing, charptr, "Expecting something before '/'");
    }

    // Collect tokens for node
    ResultType(SolsTokens, charptr) tokens = createSolsTokens();
    if (tokens.error) {
        return Error(Nothing, charptr, tokens.as.error);
    }

    // Get the previous node
    SolsNode idNode = parser->currentParent->children.at[parser->currentParent->children.count - 1];

    ResultType(SolsToken, Nothing) peek = parserPeek(parser, 0);
    if (peek.error) return Error(Nothing, charptr, "ruh roh");

    for (;;) {
        ResultType(SolsToken, Nothing) peek = parserPeek(parser, 1);
        if (peek.error) break;
        if (getPrecedence(&peek.as.success) <= STP_MUL) {
            break;
        }
        parserConsume(parser);
        addTokenToSolsTokens(&tokens.as.success, peek.as.success);
    }

    // Create node
    ResultType(SolsNode, charptr) node = createSolsNode(SNT_OP_SUB);
    if (node.error) return Error(Nothing, charptr, node.as.error);
    node.as.success.line = peek.as.success.line;

    // Parse selected tokens
    ResultType(SolsParser, charptr) putsParser = createSolsParser(&tokens.as.success);
    if (putsParser.error) return Error(Nothing, charptr, putsParser.as.error);
    putsParser.as.success.currentParent = &putsParser.as.success.output;
    ResultType(Nothing, charptr) parsed = parse(&putsParser.as.success);

    // Add any error messages from parsing
    if (parsed.error) {
        addToParserErrors(parser, parsed.as.error);
        return Success(Nothing, charptr, {});
    }

    if (putsParser.as.success.output.children.count < 1) {
        return Error(Nothing, charptr, "Expecting token after '/'");
    }

    // Copy idnode into set node
    addChildToSolsNode(&node.as.success, idNode);

    // Copy nodes into the set node
    for (size_t i = 0; i < putsParser.as.success.output.children.count; i++) {
        addChildToSolsNode(&node.as.success, putsParser.as.success.output.children.at[i]);
    }

    // Put the set node where the idNode was
    parser->currentParent->children.count--;
    addChildToSolsNode(parser->currentParent, node.as.success);

    return Success(Nothing, charptr, {});
}

static inline ResultType(Nothing, charptr) parseEqual(SolsParser* parser) {
    if (parser->currentParent->children.count < 1) {
        return Error(Nothing, charptr, "Expecting something before '=='");
    }

    // Collect tokens for node
    ResultType(SolsTokens, charptr) tokens = createSolsTokens();
    if (tokens.error) {
        return Error(Nothing, charptr, tokens.as.error);
    }

    // Get the previous node
    SolsNode idNode = parser->currentParent->children.at[parser->currentParent->children.count - 1];

    ResultType(SolsToken, Nothing) peek = parserPeek(parser, 0);
    if (peek.error) return Error(Nothing, charptr, "ruh roh");

    for (;;) {
        ResultType(SolsToken, Nothing) peek = parserPeek(parser, 1);
        if (peek.error) break;
        if (getPrecedence(&peek.as.success) <= STP_COMPARE) {
            break;
        }
        parserConsume(parser);
        addTokenToSolsTokens(&tokens.as.success, peek.as.success);
    }

    // Create node
    ResultType(SolsNode, charptr) node = createSolsNode(SNT_OP_EQUAL);
    if (node.error) return Error(Nothing, charptr, node.as.error);
    node.as.success.line = peek.as.success.line;

    // Parse selected tokens
    ResultType(SolsParser, charptr) putsParser = createSolsParser(&tokens.as.success);
    if (putsParser.error) return Error(Nothing, charptr, putsParser.as.error);
    putsParser.as.success.currentParent = &putsParser.as.success.output;
    ResultType(Nothing, charptr) parsed = parse(&putsParser.as.success);

    // Add any error messages from parsing
    if (parsed.error) {
        addToParserErrors(parser, parsed.as.error);
        return Success(Nothing, charptr, {});
    }

    if (putsParser.as.success.output.children.count < 1) {
        return Error(Nothing, charptr, "Expecting token after '=='");
    }

    // Copy idnode into set node
    addChildToSolsNode(&node.as.success, idNode);

    // Copy nodes into the set node
    for (size_t i = 0; i < putsParser.as.success.output.children.count; i++) {
        addChildToSolsNode(&node.as.success, putsParser.as.success.output.children.at[i]);
    }

    // Put the equal node where the idNode was
    parser->currentParent->children.count--;
    addChildToSolsNode(parser->currentParent, node.as.success);

    return Success(Nothing, charptr, {});
}

static inline ResultType(Nothing, charptr) parseLiteral(SolsParser* parser) {
    ResultType(SolsToken, Nothing) peek = parserPeek(parser, 0);
    if (peek.error) {
        return Error(Nothing, charptr, "ruh roh");
    }
    ResultType(SolsNode, charptr) node = createSolsNode(SNT_LITERAL, peek.as.success.as.literal);
    if (node.error) {
        Estr err = CREATE_ESTR(node.as.error);
        APPEND_ESTR(err, " (in parseLiteral() function)");
        return Error(Nothing, charptr, err.str);
    }
    node.as.success.line = peek.as.success.line;
    GroundValue value;
    switch (peek.as.success.as.literal.type) {
        case SLT_INT: {
            value = groundCreateValue(INT, peek.as.success.as.literal.as.intv);
            break;
        }
        case SLT_DOUBLE: {
            value = groundCreateValue(DOUBLE, peek.as.success.as.literal.as.doublev);
            break;
        }
        case SLT_STRING: {
            value = groundCreateValue(STRING, peek.as.success.as.literal.as.stringv);
            break;
        }
        case SLT_BOOL: {
            value = groundCreateValue(BOOL, peek.as.success.as.literal.as.boolv);
            break;
        }
        case SLT_CHAR: {
            value = groundCreateValue(CHAR, peek.as.success.as.literal.as.charv);
            break;
        }
    }
    node.as.success.accessArg = (GroundArg) {
        .type = VALUE,
        .value.value = value
    };
    addChildToSolsNode(parser->currentParent, node.as.success);
    return Success(Nothing, charptr, {});
}

static inline ResultType(Nothing, charptr) parsePuts(SolsParser* parser) {

    // Collect tokens for node
    ResultType(SolsTokens, charptr) tokens = createSolsTokens();
    if (tokens.error) {
        return Error(Nothing, charptr, tokens.as.error);
    }

    ResultType(SolsToken, Nothing) peek = parserPeek(parser, 0);
    if (peek.error) return Error(Nothing, charptr, "ruh roh");

    for (;;) {
        ResultType(SolsToken, Nothing) peek = parserPeek(parser, 1);
        if (peek.error) break;
        if (getPrecedence(&peek.as.success) <= STP_PUTS) {
            break;
        }
        parserConsume(parser);
        addTokenToSolsTokens(&tokens.as.success, peek.as.success);
    }

    // Create node
    ResultType(SolsNode, charptr) node = createSolsNode(SNT_PUTS);
    if (node.error) return Error(Nothing, charptr, node.as.error);
    node.as.success.line = peek.as.success.line;

    // Parse selected tokens
    ResultType(SolsParser, charptr) putsParser = createSolsParser(&tokens.as.success);
    if (putsParser.error) return Error(Nothing, charptr, putsParser.as.error);
    putsParser.as.success.currentParent = &putsParser.as.success.output;
    ResultType(Nothing, charptr) parsed = parse(&putsParser.as.success);

    // Add any error messages from parsing
    if (parsed.error) {
        addToParserErrors(parser, parsed.as.error);
        return Success(Nothing, charptr, {});
    }

    // Copy nodes into the sols node
    for (size_t i = 0; i < putsParser.as.success.output.children.count; i++) {
        addChildToSolsNode(&node.as.success, putsParser.as.success.output.children.at[i]);
    }

    addChildToSolsNode(parser->currentParent, node.as.success);

    return Success(Nothing, charptr, {});
}

ResultType(Nothing, charptr) parse(SolsParser* parser) {
    parser->currentParent = &parser->output;
    for (;;) {
        ResultType(SolsToken, Nothing) token = parserConsume(parser);
        if (token.error) {
            break;
        }
        switch (token.as.success.type) {
            case STT_IDENTIFIER: PARSER_HANDLE(Identifier);
            case STT_LITERAL: PARSER_HANDLE(Literal);
            case STT_KW_PUTS: PARSER_HANDLE(Puts);
            case STT_OP_SET: PARSER_HANDLE(Set);
            case STT_OP_ADD: PARSER_HANDLE(Add);
            case STT_OP_SUB: PARSER_HANDLE(Sub);
            case STT_OP_MUL: PARSER_HANDLE(Mul);
            case STT_OP_DIV: PARSER_HANDLE(Div);
            case STT_OP_EQUAL: PARSER_HANDLE(Equal);
        }
    }
    if (parser->errors.count > 0) {
        Estr estr = CREATE_ESTR("");
        for (size_t i = 0; i < parser->errors.count; i++) {
            APPEND_ESTR(estr, parser->errors.at[i]);
            APPEND_ESTR(estr, "\n");
        }
        return Error(Nothing, charptr, estr.str);
    }
    return Success(Nothing, charptr, {});
}

ResultType(SolsToken, Nothing) parserLookAt(SolsParser* parser, size_t where) {
    if (parser->input == NULL) {
        return Error(SolsToken, Nothing, {});
    }
    if (where >= parser->input->count) {
        return Error(SolsToken, Nothing, {});
    }
    return Success(SolsToken, Nothing, parser->input->at[where]);
}

ResultType(SolsToken, Nothing) parserPeek(SolsParser* parser, int64_t ahead) {
    if (parser->input == NULL) {
        return Error(SolsToken, Nothing, {});
    }
    if (parser->current + ahead - 1 >= parser->input->count) {
        return Error(SolsToken, Nothing, {});
    } 
    return Success(SolsToken, Nothing, parser->input->at[parser->current + ahead - 1]);
}

ResultType(SolsToken, Nothing) parserConsume(SolsParser* parser) {
    if (parser->input == NULL) {
        return Error(SolsToken, Nothing, {});
    }
    if (parser->current >= parser->input->count) {
        return Error(SolsToken, Nothing, {});
    } 
    return Success(SolsToken, Nothing, parser->input->at[parser->current ++]);
}