#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "types.h"
#include "error.h"

extern Token tokens[];
extern int tk_idx;
extern int pc;
extern CallStack call_stack;

void push_call_frame(const char *function_name, const char *filename, int line, int is_native) {
    if (call_stack.depth >= MAX_CALL_STACK) {
        return;
    }

    CallStackFrame *frame = &call_stack.frames[call_stack.depth];
    frame->function_name = function_name;
    frame->filename = filename;
    frame->line = line;
    frame->is_native = is_native;
    call_stack.depth++;
}

void pop_call_frame() {
    if (call_stack.depth > 0) {
        call_stack.depth--;
    }
}

void print_stacktrace() {
    if (call_stack.depth == 0) {
        return;
    }

    fprintf(stderr, "\n");
    fprintf(stderr, "╔════════════════════════════════════════════════════════════════╗\n");
    fprintf(stderr, "║                      STACK TRACE                               ║\n");
    fprintf(stderr, "╚════════════════════════════════════════════════════════════════╝\n");

    int frames_to_show = call_stack.depth;
    if (frames_to_show > 10) {
        frames_to_show = 10;
    }

    for (int i = call_stack.depth - 1; i >= call_stack.depth - frames_to_show; i--) {
        if (i < 0) break;

        CallStackFrame *frame = &call_stack.frames[i];
        const char *type_marker = frame->is_native ? "[native]" : "[script]";

        fprintf(stderr, "  %s ", type_marker);

        if (frame->function_name) {
            fprintf(stderr, "%s()", frame->function_name);
        } else {
            fprintf(stderr, "<anonymous>");
        }

        if (frame->filename && frame->line > 0) {
            fprintf(stderr, "\n    at %s:%d", frame->filename, frame->line);
        } else if (frame->filename) {
            fprintf(stderr, "\n    at %s", frame->filename);
        }

        fprintf(stderr, "\n");
    }

    if (call_stack.depth > 10) {
        fprintf(stderr, "  ... %d more frames\n", call_stack.depth - 10);
    }

    fprintf(stderr, "\n");
}

static const char* get_error_tip(const char *error_type, const char *message) {
    if (strstr(message, "index out of bounds") || strstr(message, "Token index")) {
        return "Check array bounds and ensure index is within valid range";
    }
    if (strstr(message, "Too many")) {
        return "Consider breaking down into smaller components or increasing limits";
    }
    if (strstr(message, "Stack overflow")) {
        return "Reduce recursion depth or local variable usage";
    }
    if (strstr(message, "Undefined variable")) {
        return "Ensure variable is declared before use with: int varname;";
    }
    if (strstr(message, "Unknown function")) {
        return "Check function name spelling and ensure it's defined before calling";
    }
    if (strstr(message, "Unexpected token")) {
        return "Check for missing semicolons, braces, or parentheses";
    }
    if (strstr(message, "division by zero") || strstr(message, "divide by zero")) {
        return "Add a check: if (divisor != 0) before division";
    }
    if (strstr(message, "Null pointer")) {
        return "Check if pointer is null before dereferencing: if (ptr != null)";
    }
    if (strstr(message, "Memory")) {
        return "Reduce memory usage or check for memory leaks";
    }
    if (strstr(message, "Unknown class") || strstr(message, "Unknown field") ||
        strstr(message, "Unknown method")) {
        return "Verify class/field/method name and ensure class is defined";
    }

    return "Review the code at the error location and check for typos";
}

static void print_code_context(int token_index) {
    if (token_index < 0 || token_index >= tk_idx) {
        return;
    }

    Token *error_token = &tokens[token_index];
    if (!error_token->filename || error_token->line <= 0) {
        return;
    }

    fprintf(stderr, "\n");
    fprintf(stderr, "╔════════════════════════════════════════════════════════════════╗\n");
    fprintf(stderr, "║                      CODE CONTEXT                              ║\n");
    fprintf(stderr, "╚════════════════════════════════════════════════════════════════╝\n");

    int start_token = token_index - 3;
    int end_token = token_index + 3;

    if (start_token < 0) start_token = 0;
    if (end_token >= tk_idx) end_token = tk_idx - 1;

    for (int i = start_token; i <= end_token && i < tk_idx; i++) {
        if (i < 0) continue;

        Token *t = &tokens[i];
        const char *marker = (i == token_index) ? ">>> " : "    ";

        fprintf(stderr, "%s", marker);

        if (t->type >= 32 && t->type < 127) {
            fprintf(stderr, "'%c' ", t->type);
        } else if (t->type == Num) {
            fprintf(stderr, "%ld ", t->val);
        } else if (t->type == Id && t->text) {
            fprintf(stderr, "%.*s ", (int)t->val, t->text);
        } else if (t->type == Str && t->text) {
            fprintf(stderr, "\"%s\" ", t->text);
        } else {
            fprintf(stderr, "[token:%d] ", t->type);
        }

        if (i == token_index) {
            fprintf(stderr, "<-- ERROR HERE");
        }

        fprintf(stderr, "\n");
    }

    fprintf(stderr, "\n");
}

void error_with_context(const char *error_type, const char *message, const char *tip) {
    fprintf(stderr, "\n");
    fprintf(stderr, "╔════════════════════════════════════════════════════════════════╗\n");
    fprintf(stderr, "║                      RUNTIME ERROR                             ║\n");
    fprintf(stderr, "╚════════════════════════════════════════════════════════════════╝\n");
    fprintf(stderr, "\n");

    fprintf(stderr, "  Error Type: %s\n", error_type ? error_type : "General Error");
    fprintf(stderr, "  Message:    %s\n", message);

    if (pc >= 0 && pc < tk_idx) {
        Token *current_token = &tokens[pc];
        if (current_token->filename) {
            fprintf(stderr, "  Location:   %s", current_token->filename);
            if (current_token->line > 0) {
                fprintf(stderr, ":%d", current_token->line);
                if (current_token->column > 0) {
                    fprintf(stderr, ":%d", current_token->column);
                }
            }
            fprintf(stderr, "\n");
        }
    }

    fprintf(stderr, "\n");

    const char *actual_tip = tip ? tip : get_error_tip(error_type, message);
    if (actual_tip) {
        fprintf(stderr, "╔════════════════════════════════════════════════════════════════╗\n");
        fprintf(stderr, "║                         TIP                                    ║\n");
        fprintf(stderr, "╚════════════════════════════════════════════════════════════════╝\n");
        fprintf(stderr, "  💡 %s\n", actual_tip);
    }

    print_code_context(pc);
    print_stacktrace();

    exit(1);
}