#include "lexer.h"
#include "SolsLiteral.h"
#include "SolsToken.h"
#include "../include/error.h"
#include "../include/estr.h"


ResultType(SolsLexer, charptr) createLexer(char* input) {
    char* inputcopy = malloc(strlen(input) + 1);
    if (inputcopy == NULL) {
        return Error(SolsLexer, charptr, "Couldn't copy string into lexer (in createLexer() function)");
    }
    strcpy(inputcopy, input);
    ResultType(SolsTokens, charptr) tokens = createSolsTokens();
    if (tokens.error) {
        Estr e = CREATE_ESTR(tokens.as.error);
        APPEND_ESTR(e, " (in createLexer() function)");
        return Error(SolsLexer, charptr, e.str);
    }
    SolsLexer lexer = {
        .input = inputcopy,
        .inputsize = strlen(inputcopy),
        .output = tokens.as.success,
        .current = 0,
    };
    return Success(SolsLexer, charptr, lexer);
}

ResultType(char, Nothing) lexerPeek(SolsLexer* lexer, size_t ahead) {
    if (lexer->input == NULL) {
        return Error(char, Nothing, {});
    }
    if (lexer->current + ahead > lexer->inputsize) {
        return Error(char, Nothing, {});
    }
    return Success(char, Nothing, lexer->input[lexer->current + ahead]);
}


ResultType(char, Nothing) lexerConsume(SolsLexer* lexer) {
    if (lexer->input == NULL) {
        return Error(char, Nothing, {});
    }
    if (lexer->current + 1 > lexer->inputsize) {
        return Error(char, Nothing, {});
    }
    return Success(char, Nothing, lexer->input[lexer->current++]);
}

ResultType(SolsToken, charptr) identifyToken(const char* token) {
    if (token[0] == '"') {
        if (token[strlen(token) - 1] == '"') {
            ResultType(SolsLiteral, charptr) literal = createSolsLiteral(SLT_STRING, token);
            if (literal.error) {
                Estr str = CREATE_ESTR(literal.as.error);
                APPEND_ESTR(str, " (in identifyToken() function)");
                return Error(SolsToken, charptr, str.str);
            }
            SolsToken tok = {
                .type = STT_LITERAL,
            };
            return Success(SolsToken, charptr, {STT_LITERAL});
        }
        return Error(SolsToken, charptr, "Unterminated string ()");
    }

    // FIXME do tihs better sometime
    if (strcmp(token, "puts") == 0) {
        return Success(SolsToken, charptr, {STT_KW_PUTS});
    }
    if (strcmp(token, "if") == 0) {
        return Success(SolsToken, charptr, {STT_KW_IF});
    }
    if (strcmp(token, "while") == 0) {
        return Success(SolsToken, charptr, {STT_KW_WHILE});
    }
    if (strcmp(token, "def") == 0) {
        return Success(SolsToken, charptr, {STT_KW_DEF});
    }
    if (strcmp(token, "struct") == 0) {
        return Success(SolsToken, charptr, {STT_KW_DEF});
    }
    // Shh, this is our little secret now
    if (strcmp(token, "{") == 0 || strcmp(token, "then")) {
        return Success(SolsToken, charptr, {STT_OPEN_CURLY});
    }
    if (strcmp(token, "}") == 0 || strcmp(token, "end") == 0) {
        return Success(SolsToken, charptr, {STT_CLOSE_CURLY});
    }
    if (strcmp(token, "(") == 0) {
        return Success(SolsToken, charptr, {STT_OPEN_PAREN});
    }
    if (strcmp(token, ")") == 0) {
        return Success(SolsToken, charptr, {STT_CLOSE_PAREN});
    }
    if (strcmp(token, "+") == 0 || strcmp(token, "plus") == 0) {
        return Success(SolsToken, charptr, {STT_OP_ADD});
    }
    if (strcmp(token, "-") == 0 || strcmp(token, "minus") == 0) {
        return Success(SolsToken, charptr, {STT_OP_SUB});
    }
    if (strcmp(token, "*") == 0 || strcmp(token, "times") == 0) {
        return Success(SolsToken, charptr, {STT_OP_MUL});
    }
    if (strcmp(token, "/") == 0 || strcmp(token, "dividedby") == 0) {
        return Success(SolsToken, charptr, {STT_OP_DIV});
    }
    if (strcmp(token, "=") == 0 || strcmp(token, "is") == 0) {
        return Success(SolsToken, charptr, {STT_OP_SET});
    }

    return Success(SolsToken, charptr, {STT_IDENTIFIER});

}

ResultType(voidptr, charptr) lex(SolsLexer* lexer) {
    if (lexer->input == NULL) {
        return Error(voidptr, charptr, "Lexer is not initialised");
    }

    ResultType(SolsTokens, charptr) tokens = createSolsTokens();
    if (tokens.error) {
        Estr e = CREATE_ESTR(tokens.as.error);
        APPEND_ESTR(e, " (in createSolsTokens() function)");
        return Error(voidptr, charptr, e.str);
    }

    lexer->output = tokens.as.success;
    lexer->current = 0;

    Estr buf = CREATE_ESTR("");
    bool inString = false;

    size_t lineNum = 1;
    size_t lineStart = 0;
    Estr currentLine = CREATE_ESTR("");

    for (; lineStart < lexer->inputsize; lineStart++) {
        if (lexer->input[lineStart] == '\n') {
            break;
        }
        char buf[] = {lexer->input[lineStart], '\0'};
        APPEND_ESTR(currentLine, buf);
    }

    for (;;) {
        ResultType(char, Nothing) chr = lexerConsume(lexer);

        if (chr.error) {
            break;
        }

        if (chr.as.success == '\n') {
            for (; lineStart < lexer->inputsize; lineStart++) {
                if (lexer->input[lineStart] == '\n') {
                    break;
                }
                char buf[] = {lexer->input[lineStart], '\0'};
                APPEND_ESTR(currentLine, buf);
            }
            lineNum ++;
        }

        if (inString) {
            char str[2] = { chr.as.success, '\0' };
            APPEND_ESTR(buf, str);
            if (chr.as.success == '"') {
                inString = false;
            }
        }

        switch (chr.as.success) {
            case '"': {
                inString = true;
                APPEND_ESTR(buf, "\"");
                break;
            }
            case ' ': {
                if (!buf.destroyed) {
                    ResultType(SolsToken, charptr) result = identifyToken(buf.str);
                    if (result.error) {
                        Estr error = CREATE_ESTR("Parsing Error:\n");
                        APPEND_ESTR(error, "On line ");
                        char buf[256];
                        snprintf(buf, sizeof(buf), "%zu", lineNum);
                        APPEND_ESTR(error, buf);
                        APPEND_ESTR(error, "\n");
                        APPEND_ESTR(error, currentLine.str);
                        APPEND_ESTR(error, "\n");
                        APPEND_ESTR(error, "Why: ");
                        APPEND_ESTR(error, result.as.error);
                        APPEND_ESTR(error, "\n");
                        return Error(voidptr, charptr, error.str);
                    }
                }
            }
        }
    }

    return Success(voidptr, charptr, NULL);
}