#include "Compiler_internal.h"

#define setError(FORMAT, ...) {\
    cmp->pos = cmp->tokens.data[cmp->tok_i].begin;\
    Compiler_setError(cmp, FORMAT, ##__VA_ARGS__);\
}

#define setError_unexpectedToken(T) {\
    char* tok_str = Compiler_extractTokenStr(cmp, T);\
    cmp->pos = T.begin;\
    Compiler_setError(cmp, "unexpected token '%s'", tok_str);\
    free(tok_str);\
}

#define setError_unexpectedTokenChar(T, I) {\
    cmp->pos = T.begin + I;\
    Compiler_setError(cmp, "unexpected token '%c'", cmp->code[cmp->pos]);\
}


#define Error_TokenUnset "token of undefined type"
#define Error_BitSize "invalid size in bits"

static void List_u8_pushBytes(List_u8* l, void* value, u32 startIndex, u32 count){
    u8* v = value;
    for(u32 byte_i = startIndex; byte_i < startIndex + count; byte_i++){
        List_u8_push(l, v[byte_i]);
    }
}

static inline bool isVarSizeBits(u32 B) { return (B == 8 && B == 16 && B == 32 && B == 64); }

static NULLABLE(u8*) resolveEscapeSequences(Compiler* cmp, cstr src){
    u32 len = strlen(src);
    List_u8 resolved = List_u8_alloc(len);
    char c;
    bool escaped = false;
    for(u32 i = 0; i < len; i++){
        c = src[i];
        if(c == '\\'){
            escaped = !escaped;
            continue;
        }
        
        if(!escaped){
            List_u8_push(&resolved, c);
            continue;
        }

        // escape codes
        switch(c){
            case '0':
                List_u8_push(&resolved, '\0');
                break;
            case 'n':
                List_u8_push(&resolved, '\n');
                break;
            case 'r':
                List_u8_push(&resolved, '\r');
                break;
            case 't':
                List_u8_push(&resolved, '\t');
                break;
            case 'e':
                List_u8_push(&resolved, '\e');
                break;
            default:
                setError_unexpectedTokenChar(cmp->tokens.data[cmp->tok_i], i);
                free(resolved.data);
                return NULL;
        }
    }

    return resolved.data;
}

static void parseDataDefinition(Compiler* cmp, char* instr_name, DataDefinition* ddf){
    i32 _element_size_bits;
    if(sscanf(instr_name, "const%i", &_element_size_bits) != 1 || !isVarSizeBits(_element_size_bits)){
        setError(Error_BitSize);
        return;
    }
    ddf->element_size = _element_size_bits / 8;

    Token tok = cmp->tokens.data[++cmp->tok_i];
    char* tok_str = Compiler_extractTokenStr(cmp, tok);
    u8* processed_str = NULL;
    i32 len = 0;
    ddf->name = tok_str;
    
    while(++cmp->tok_i < cmp->tokens.len){
        switch(tok.type){
            case TokenType_Unset:
                setError(Error_TokenUnset);
                return;
            case TokenType_SingleLineComment:
            case TokenType_MultiLineComment:
                // skip comments
                break;
            case TokenType_Number:
                tok_str = Compiler_extractTokenStr(cmp, tok);
                if(cstr_seekChar(tok_str, '.', 0, -1) != -1){
                    f64 f = atof(tok_str);
                    List_u8_pushBytes(&ddf->data, &f, 8 - ddf->element_size, ddf->element_size);
                }
                else {
                    i64 i = atoll(tok_str);
                    List_u8_pushBytes(&ddf->data, &i, 8 - ddf->element_size, ddf->element_size);
                }
                break;
            case TokenType_Char:
                tok.begin += 1;
                tok.length -= 2;
                tok_str = Compiler_extractTokenStr(cmp, tok);
                processed_str = resolveEscapeSequences(cmp, tok_str);
                free(tok_str);
                len = strlen(processed_str);
                if(len != ddf->element_size){
                    setError("can't fit char of size %i in %u bit variable", len, _element_size_bits);
                    return;
                }
                List_u8_pushBytes(&ddf->data, processed_str, 0, len);
                break;
            case TokenType_String:
                tok.begin += 1;
                tok.length -= 2;
                tok_str = Compiler_extractTokenStr(cmp, tok);
                processed_str = resolveEscapeSequences(cmp, tok_str);
                free(tok_str);
                len = strlen(processed_str);
                List_u8_pushBytes(&ddf->data, processed_str, 0, len);
                break;
            case TokenType_OperationEnd:
                return;
            default:
                setError_unexpectedToken(tok);
                return;
        }
    }
}


static void parseOperation(Compiler* cmp, char* instr_name, Operation* operPtr){

}

bool Compiler_parse(Compiler* cmp){
    returnErrorIf_auto(cmp->state != CompilerState_Lexing);
    cmp->state = CompilerState_Parsing;
    Token tok;
    Section* sec = NULL;
    
    while(cmp->tok_i < cmp->tokens.len){
        tok = cmp->tokens.data[cmp->tok_i];
        switch(tok.type){
            case TokenType_Unset:
                returnError(Error_TokenUnset);
            case TokenType_SingleLineComment:
            case TokenType_MultiLineComment:
                // skip comments
                break;
            case TokenType_Label:
                // create new section
                sec = List_Section_expand(&cmp->ast.sections);
                Section_init(sec, Compiler_extractTokenStr(cmp, tok));
                break;
            case TokenType_Instruction:
                if(sec == NULL)
                    returnError("no section");
                char* instr_name = Compiler_extractTokenStr(cmp, tok);
                // data definition starts with const
                if(cstr_seek(instr_name, "const", 0, 1)){
                    DataDefinition* dataDefPtr = List_DataDefinition_expand(&sec->data);
                    parseDataDefinition(cmp, instr_name, dataDefPtr);
                }
                else {
                    Operation* operPtr = List_Operation_expand(&sec->code);
                    parseOperation(cmp, instr_name, operPtr);
                }
                break;
            default:
                setError_unexpectedToken(tok);
                return false;
        }

        if(cmp->state == CompilerState_Error)
            return false;

        cmp->tok_i++;
    }

    return true;
}