#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include "source.h"

void source_init(struct source *src, str name, str contents)
{
    src->name = name;
    src->offset = 0;
    src->contents = contents;
    src->strings.len = src->strings.cap = 0;
    src->strings.ptr = nullptr;
}

void source_error(struct source *src, struct range loc, const char *fmt, ...)
{
    char *p_start = src->contents.ptr + loc.start;
    char *p_end = src->contents.ptr + loc.end;

    unsigned int lineno = 0;
    str iter = src->contents;
    str line;
    do {
        line = str_walk(&iter, S("\n"));
        lineno++;
    } while (line.ptr + line.len <= p_start);

    fprintf(stderr, "parse error in %.*s:%u: ", PSTR(src->name), lineno);

    va_list args;
    va_start(args, fmt);
    vfprintf(stderr, fmt, args);
    va_end(args);
    
    fprintf(stderr, "\n");

    while (line.ptr && line.ptr < p_end) {
        fprintf(stderr, " %4u: %.*s\n", lineno, PSTR(line));
        fprintf(stderr, "       ");
        for (size_t i = 0; i < line.len+1; i++) {
            char *p = line.ptr + i;
            fprintf(stderr, "%c", p >= p_start && p < p_end ? '^' : ' ');
        }
        fprintf(stderr, "\n");

        line = str_walk(&iter, S("\n"));
        lineno++;
    }

    exit(EXIT_FAILURE);
}

void source_free(struct source *src)
{
    free(src->contents.ptr);
    for (size_t i = 0; i < src->strings.len; i++)
        free(src->strings.ptr[i].ptr);
    free(src->strings.ptr);
}