#include "log.h"
#include "util.h"

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>

static LogError* s_logError = NULL;

void log_set_output(LogError* destination) {
    s_logError = destination;
}

void log_error(const char* msg) {
    if (s_logError != NULL) {
        s_logError(msg);
    } else {
        fprintf(stderr, "Error: %s\n", msg);
    }
}

void log_on_line(Location* loc, int to_column, const char* msg, ...) {
    char* line_prefix = NULL;
    char* formatted_msg = NULL;
    char* header = NULL;
    char* buffer = NULL;

    line_prefix = format_string("%d| ", loc->line);
    if (!line_prefix) goto cleanup;

    int caret_len = to_column - loc->column_start + 1;
    if (caret_len < 1) caret_len = 1;

    // Format the message
    va_list args;
    va_start(args, msg);
    formatted_msg = format_string_va(msg, args);
    va_end(args);
    if (!formatted_msg) goto cleanup;

    // Header logic
    if (loc->filename && loc->filename[0] != '\0') {
        header = format_string("--- %s ---\n", loc->filename);
    } else {
        header = format_string("--- \n");
    }
    if (!header) goto cleanup;

    size_t total_size = strlen(header) + 20 +
                        strlen(line_prefix) + loc->line_text.length + 2 + // line| text\n
                        strlen(line_prefix) + loc->column_start - 1 + caret_len + 2 + // indent + ^^\n
                        strlen(line_prefix) + 3 + strlen(formatted_msg) + 2 + // indent + msg\n
                        10;

    buffer = (char*)malloc(total_size);
    if (!buffer) goto cleanup;

    char* p = buffer;
    p += sprintf(p, "%s", header);
    p += sprintf(p, "%s%.*s\n", line_prefix, (int)loc->line_text.length, loc->line_text.data);

    // Caret line
    for (int i = 0; i < (int)(strlen(line_prefix) + loc->column_start - 1); i++) *p++ = ' ';
    for (int i = 0; i < caret_len; i++) *p++ = '^';
    *p++ = '\n';

    // Message line
    for (size_t i = 0; i < strlen(line_prefix); i++) *p++ = ' ';
    p += sprintf(p, "%s\n", formatted_msg);

    *p = '\0';

    log_error(buffer);

cleanup:
    free(line_prefix);
    free(formatted_msg);
    free(header);
    free(buffer);
}