#define LIST_IMPLEMENTATION
#include "list.h"

#include "../include/SterlingCompiler.h"

# ifndef strndup
char	*strndup(const char *s, size_t n) {
	char	*str = calloc(n + 1, sizeof(char));
	memcpy(str, s, n);
	return (str);
}
# endif

char	*LoadFile(const char *filename) {
	FILE	*file = NULL;
	char	*data = NULL;
	file = fopen(filename, "r");
	assert(file);
	fseek(file, 0, SEEK_END);
    long size = ftell(file);
    fseek(file, 0, SEEK_SET);
	data = (char *)malloc(size + 1);
	assert(data);
	fread(data, 1, size, file);
	data[size] = 0x00;
	fclose(file);
	return (data);
}

bool IsWhitespace(const char *s) {
    while (*s) {
        if (!isspace((unsigned char)*s)) return false;
        s++;
    }
    return true;
}

bool IsNumeric(const char *s) {
    if (!s || !*s) return false;
    for (int i = 0; s[i]; i++) {
        if (!isdigit((unsigned char)s[i])) return false;
    }
    return true;
}

bool IsComplexNumeric(const char *s, size_t len) {
    if (len == 0) return false;

    // Most numbers start with a digit
    if (isdigit((unsigned char)s[0])) return true;

    // Floats can start with a dot (e.g., .5)
    if (s[0] == '.' && len > 1 && isdigit((unsigned char)s[1])) return true;

    return false;
}

void ResolveTrigraphs(char *data) {
    char *src = data, *dst = data;
    while (*src) {
        if (src[0] == '?' && src[1] == '?' && src[2]) {
            char c = 0;
            switch (src[2]) {
                case '=':  c = '#';  break; case '/':  c = '\\'; break;
                case '\'': c = '^';  break; case '(':  c = '[';  break;
                case ')':  c = ']';  break; case '!':  c = '|';  break;
                case '<':  c = '{';  break; case '>':  c = '}';  break;
                case '-':  c = '~';  break;
            }
            if (c) { *dst++ = c; src += 3; continue; }
        }
        *dst++ = *src++;
    }
    *dst = '\0';
}

typedef struct {
    list_iter_t iter;
    list_t      *tokens;
    bool        error;
} Parser_t;

// Initialize the parser
Parser_t ParserInit(list_t *lst) {
    return (Parser_t){ .iter = ListGetIter(lst), .tokens = lst, .error = false };
}

// Look at current token
Token_t* Peek(Parser_t *p) {
    if (!p->iter.current) return NULL;
    return (Token_t*)p->iter.current->data;
}

// Move to next
void Advance(Parser_t *p) {
    if (p->iter.current) p->iter.current = p->iter.current->next;
}

// Check if current matches type (and optionally value)
bool Match(Parser_t *p, TKN_CTX ctx, const char *val) {
    Token_t *t = Peek(p);
    if (!t || (t->ctx != ctx)) return false;
    if (val && strcmp(t->data, val) != 0) return false;

    Advance(p);
    return true;
}

// Required token; errors out if not found
Token_t* Expect(Parser_t *p, TKN_CTX ctx, const char *val) {
    Token_t *t = Peek(p);
    if (!t || (t->ctx != ctx) || (val && strcmp(t->data, val) != 0)) {
        printf("Syntax Error: Expected '%s', but found '%s'\n",
                val ? val : "specific type", t ? t->data : "EOF");
        p->error = true;
        return NULL;
    }
    Advance(p);
    return t;
}

void	ClearTokens(void*arg) {
	Token_t *tok = arg;
	free(tok->data);
	free(tok);
}

node_t* NewNode(void* data) {
    node_t* n = calloc(1, sizeof(node_t));
    if(n) n->data = data;
    return n;
}

Token_t* NewToken(const char* start, size_t len, TKN_CTX ctx) {
    Token_t* t = malloc(sizeof(Token_t));
    t->data = strndup(start, len);
    t->size = len;
    t->ctx = ctx;
    return t;
}

void PushToken(list_t *lst, const char *start, const char *end, TKN_CTX ctx) {
    if (end <= start) return;
    ListPushBack(lst, NewToken(start, end - start, ctx));
}

void IdentifyTokens(list_t *lst) {
    for (node_t *curr = lst->first; curr; curr = curr->next) {
        Token_t *t = (Token_t *)curr->data;

        // Skip nodes that were already identified (like TOK_STRING or munched TOK_OP)
        if (t->ctx != TOK_RAW) continue;

        // 1. Check Keyword Registry (Highest Priority)
        bool found = false;
        for (int i = 0; KEYWORD_TABLE[i].name != NULL; i++) {
            if (strcmp(t->data, KEYWORD_TABLE[i].name) == 0) {
                t->ctx = KEYWORD_TABLE[i].ctx;
                found = true;
                break;
            }
        }
        if (found) continue;

        // 2. Check for Numeric Literals (0x..., 3.14, 100L)
        if (isdigit((unsigned char)t->data[0]) || (t->data[0] == '.' && t->size > 1 && isdigit(t->data[1]))) {
            t->ctx = TOK_NUM;
            continue;
        }

        // 3. Check for Identifiers (my_var, @comptime)
        if (isalpha((unsigned char)t->data[0]) || t->data[0] == '_' || t->data[0] == '@') {
            t->ctx = TOK_ID;
            continue;
        }

        // 4. Check for Operators/Symbols (;, +, -, #)
        // If it's in our SYMBOLS string, it's an operator or preprocessor trigger
        if (strchr(SYMBOLS, t->data[0])) {
            // Special case for '#' which is often its own thing
            if (t->data[0] == '#') t->ctx = TOK_PREPROC;
            else t->ctx = TOK_OP;
            continue;
        }
    }
}

void ApplyTypeAliases(list_t *lst) {
    for (node_t *curr = lst->first; curr; curr = curr->next) {
        Token_t *t = curr->data;
        // If we see 'int', we could programmatically replace it
        // with the sequence ': 4' during a transformation pass.
        if (t->ctx == TOK_ID && strcmp(t->data, "int") == 0) {
            // Logic to transform token...
        }
    }
}

void ListSplitToken(list_t *lst, node_t *node, size_t index) {
    Token_t *t = (Token_t *)node->data;

    // Create the suffix node first
    Token_t *suffix = NewToken(t->data + index, t->size - index, TOK_RAW);
    node_t *new_node = NewNode(suffix);
    new_node->next = node->next;
    node->next = new_node;
    if (lst->last == node) lst->last = new_node;
    lst->size++;

    // Truncate the original (prefix)
    char *new_prefix = strndup(t->data, index);
    free(t->data);
    t->data = new_prefix;
    t->size = index;
}

void InitialScanner(char *data, list_t *tkn_lst) {
    char *curr = data, *start = data;

    while (*curr) {
        // 1. Handle Wide or Normal Strings/Chars
        // Check for 'L' followed immediately by a quote
        bool is_wide = (*curr == 'L' && (curr[1] == '\"' || curr[1] == '\''));
        if (*curr == '\"' || *curr == '\'' || is_wide) {
            PushToken(tkn_lst, start, curr, TOK_RAW);

            char *s_start = curr;
            if (is_wide) curr++; // Advance past 'L'

            char q = *curr;
            curr++; // Skip opening quote
            while (*curr && *curr != q) {
                if (*curr == '\\' && curr[1]) curr++; // Skip escaped char
                curr++;
            }
            if (*curr) curr++; // Skip closing quote

            PushToken(tkn_lst, s_start, curr, TOK_STRING);
            start = curr;
        }
        // 2. Handle Comments (Same as before)
        else if (*curr == '/' && (curr[1] == '/' || curr[1] == '*')) {
            PushToken(tkn_lst, start, curr, TOK_RAW);
            if (curr[1] == '/') { while (*curr && *curr != '\n') curr++; }
            else {
                curr += 2;
                while (*curr && !(*curr == '*' && curr[1] == '/')) curr++;
                if (*curr) curr += 2;
            }
            start = curr;
        }
        else curr++;
    }
    PushToken(tkn_lst, start, curr, TOK_RAW);
}

void RefineSymbols(list_t *tkn_lst) {
    for (node_t *curr = tkn_lst->first; curr; ) {
        Token_t *t = curr->data;
		//IsComplexNumeric(t->data, t->size) ||
		if (t->ctx != TOK_RAW || (t->size == 1 && strchr(SYMBOLS, t->data[0]))) {
            curr = curr->next;
            continue;
        }

        size_t pos = strcspn(t->data, SYMBOLS);
        if (pos < t->size) {
            ListSplitToken(tkn_lst, curr, (pos == 0) ? 1 : pos);
            // Don't move curr yet, we might have more symbols in the suffix
        } else {
            curr = curr->next;
        }
	}
}

void MunchFloats(list_t *lst) {
    for (node_t *n = lst->first; n && n->next && n->next->next; ) {
        Token_t *t1 = n->data, *dot = n->next->data, *t2 = n->next->next->data;

        // Look for [Digit] [.] [Digit]
        if (isdigit(t1->data[0]) && dot->data[0] == '.' && dot->size == 1 && isdigit(t2->data[0])) {
            size_t new_size = t1->size + 1 + t2->size;
            char *buf = malloc(new_size + 1);
            sprintf(buf, "%s.%s", t1->data, t2->data);

            free(t1->data);
            t1->data = buf;
            t1->size = new_size;
            t1->ctx = TOK_NUM; // Mark it now!

            // Remove '.' and '14'
            for(int i=0; i<2; i++) {
                node_t *rem = n->next;
                n->next = rem->next;
                if (lst->last == rem) lst->last = n;
                ClearTokens(rem->data); free(rem);
                lst->size--;
            }
            continue;
        }
        n = n->next;
    }
}

void MunchScientificNotation(list_t *lst) {
    for (node_t *n = lst->first; n && n->next && n->next->next; ) {
        Token_t *t1 = n->data;
        Token_t *op = n->next->data;
        Token_t *t2 = n->next->next->data;

        // Check if t1 ends with 'e' or 'E' (and t1 is currently RAW)
        if (t1->ctx == TOK_RAW && t1->size > 0) {
            char last = tolower((unsigned char)t1->data[t1->size - 1]);

            if (last == 'e' &&
                (op->data[0] == '+' || op->data[0] == '-') && op->size == 1 &&
                isdigit((unsigned char)t2->data[0])) {

                // We found a match! (e.g., "1e" + "-" + "5")
                size_t new_size = t1->size + op->size + t2->size;
                char *new_data = malloc(new_size + 1);

                sprintf(new_data, "%s%s%s", t1->data, op->data, t2->data);

                free(t1->data);
                t1->data = new_data;
                t1->size = new_size;

                // Remove the op and t2 nodes
                for (size_t i = 0; i < 2; i++) {
                    node_t *to_remove = n->next;
                    n->next = to_remove->next;
                    if (lst->last == to_remove) lst->last = n;
                    ClearTokens(to_remove->data);
                    free(to_remove);
                    lst->size--;
                }
                // Check this same node again (in case of weird nesting, though rare here)
                continue;
            }
        }
        n = n->next;
    }
}

void MunchTokens(list_t *lst) {
    node_t *curr = lst->first;

    while (curr) {
        Token_t *t1 = curr->data;
        if (t1->ctx != TOK_RAW && t1->ctx != TOK_OP) {
            curr = curr->next;
            continue;
        }

        bool matched = false;
        for (size_t i = 0; MUNCH_TABLE[i].op; i++) {
            size_t len = MUNCH_TABLE[i].len;

            // 1. Peek ahead to see if we have enough nodes
            node_t *temp = curr;
            char buffer[5] = {0}; // Max munch is 4
            size_t nodes_found = 0;

            for (size_t j = 0; j < len && temp; j++) {
                Token_t *tk = temp->data;
                if (tk->size != 1) break; // Multi-char tokens can't be part of a new munch
                buffer[j] = tk->data[0];
                temp = temp->next;
                nodes_found++;
            }

            // 2. Compare buffer to table entry
            if (nodes_found == len && strcmp(buffer, MUNCH_TABLE[i].op) == 0) {
                // SUCCESS: Consolidate 'len' nodes into 'curr'
                free(t1->data);
                t1->data = strndup(MUNCH_TABLE[i].op, len);
                t1->size = len;
                t1->ctx = (MUNCH_TABLE[i].op[0] == '%') ? TOK_PREPROC : TOK_OP;

                // Remove the 'tail' nodes
                for (size_t j = 1; j < len; j++) {
                    node_t *to_remove = curr->next;
                    curr->next = to_remove->next;
                    if (lst->last == to_remove) lst->last = curr;
                    ClearTokens(to_remove->data);
                    free(to_remove);
                    lst->size--;
                }
                matched = true;
                break;
            }
        }
        // If we munched, stay on 'curr' to see if a new sequence formed
        if (!matched) curr = curr->next;
    }
}

void RefineRawNodes(list_t *tkn_lst) {
    node_t *curr = tkn_lst->first;
    //node_t *prev = NULL;

    while (curr) {
        Token_t *t = (Token_t *)curr->data;
        if (t->ctx == TOK_RAW) {
            char *span = NULL;
            char *to_split = strndup(t->data, t->size);
            char *tok = strtok_r(to_split, " \t\r\n", &span);

            if (tok) {
                free(t->data);
                t->size = strlen(tok);
                t->data = strndup(tok, t->size);

                node_t *last_inserted = curr;
                tok = strtok_r(NULL, " \t\r\n", &span);

                while (tok) {
                    Token_t *new_t = calloc(1, sizeof(Token_t));
                    new_t->size = strlen(tok);
                    new_t->data = strndup(tok, new_t->size);
                    new_t->ctx = TOK_RAW;

                    node_t *new_node = calloc(1, sizeof(node_t));
                    new_node->data = new_t;

                    new_node->next = last_inserted->next;
                    last_inserted->next = new_node;

                    if (tkn_lst->last == last_inserted) tkn_lst->last = new_node;

                    last_inserted = new_node;
                    tkn_lst->size++;
                    tok = strtok_r(NULL, " \t\r\n", &span);
                }
                curr = last_inserted;
            }
            free(to_split);
        }
        //prev = curr;
        curr = curr->next;
    }
}

void PruneWhitespaceNodes(list_t *lst) {
    node_t *curr = lst->first;
    node_t *prev = NULL;

    while (curr) {
        Token_t *t = (Token_t *)curr->data;
        if (t->ctx == TOK_RAW && IsWhitespace(t->data)) {
            // Unlink and free
            node_t *temp = curr;
            if (prev) prev->next = curr->next;
            else lst->first = curr->next;

            if (lst->last == temp) lst->last = prev;

            curr = curr->next;
            ClearTokens(temp->data);
            free(temp);
            lst->size--;
        } else {
            prev = curr;
            curr = curr->next;
        }
    }
}

/*
// Modular function to register new identifiers
void RegisterIdentifier(const char *name, TKN_CTX type) {
    //insert this into a Hash Map.
    //this is where user-defined types go.
}
*/

void ParseVarDeclaration(Parser_t *p) {
    // 1. We already saw 'var' (the trigger)

    // 2. Expect an Identifier (the name)
    Token_t *name = Expect(p, TOK_ID, NULL);
    if (p->error) return;

    // 3. Expect the separator ':'
    Expect(p, TOK_OP, ":");
    if (p->error) return;

    // 4. Expect the size (numeric)
    Token_t *size = Expect(p, TOK_NUM, NULL);
    if (p->error) return;

    printf("Defined variable '%s' with size %s bytes.\n", name->data, size->data);

    // 5. Finalize with semicolon
    Expect(p, TOK_OP, ";");
}

void Parse(Parser_t *p) {
    while (Peek(p) != NULL && !p->error) {
        Token_t *t = Peek(p);

        if (t->ctx == TOK_KEY && strcmp(t->data, "var") == 0) {
            Advance(p); // Consume 'var'
            ParseVarDeclaration(p);
        }
        else {
            printf("Unknown token: %s\n", t->data);
            Advance(p);
        }
    }
}

const char* CtxToString(TKN_CTX ctx) {
    if (ctx & TOK_KEY)     return "KEYWORD";
    if (ctx & TOK_ID)      return "IDENTIFIER";
    if (ctx & TOK_NUM)     return "NUMBER";
    if (ctx & TOK_OP)      return "OPERATOR";
    if (ctx & TOK_STRING)  return "STRING";
    if (ctx & TOK_PREPROC) return "PREPROCESS";
    if (ctx & TOK_COMMENT) return "COMMENT";
    if (ctx & TOK_RAW)     return "RAW";
    if (ctx & TOK_LITERAL) return "LITERAL";
    if (ctx & TOK_NONE)    return "NONE";
    return "UNKNOWN";
}

/*
pass on ";(){}[]$%&*$#@!?:,.<>|_-+=~`"
and give each token a context
let's replace preprocessor (include, define, etc)
let's do recursive parsing everywhere that need it
compile time reflection (@comptime or @reflect)
metaprogramming logic annotation if i do it lastly** may not be
*/
int	main(int ac, char **av) {
	if (ac <= 1) return printf("No file specified\n"), -1;

	char* data = LoadFile(av[1]);
	assert(data);
	ResolveTrigraphs(data);

	list_t *tkn_lst = ListInit(NULL);
	assert(tkn_lst);
	InitialScanner(data, tkn_lst);
	PruneWhitespaceNodes(tkn_lst);
	RefineRawNodes(tkn_lst);
	RefineSymbols(tkn_lst);
	MunchFloats(tkn_lst);
	MunchScientificNotation(tkn_lst);
	MunchTokens(tkn_lst);
	IdentifyTokens(tkn_lst);

	list_iter_t iter = ListGetIter(tkn_lst);
	printf("\n--- TOKEN STREAM ---\n");
    printf("%-6s | %-12s | %s\n", "HEX", "CONTEXT", "VALUE");
    printf("-------|--------------|----------\n");
	while (iter.current) {
        Token_t *t = (Token_t *)iter.current->data;

        // Use CtxToString for the middle column
        printf("[0x%04X] | %-12s | %s\n",
               t->ctx,
               CtxToString(t->ctx),
               t->data);

        iter.current = iter.current->next;
    }
    printf("--------------------\n");

	//Parser_t p = ParserInit(tkn_lst);
	//Parse(&p);

	//Ast
	//print all error and check correction available
	//symbletable
	//type check
	//metaanalyze to know what how to put it into IR (as asm allow for metaprog)

	//create ir by resolving ast on multiple thread

	ListFree(tkn_lst, ClearTokens);
	free(data);
	return(0);
}
//test