#include "utils.h"
#include "messages.h"

#include <stdio.h>
#include <stdbool.h>
#include <sys/stat.h>
#include <crprintf.h>

static const char *const js_extensions[] = {
  ".js", ".ts", 
  ".cjs", ".mjs", 
  ".jsx", ".tsx", NULL
};

int hex_digit(char c) {
  static const int8_t lookup[256] = {
    ['0']=0, ['1']=1, ['2']=2, ['3']=3, ['4']=4, ['5']=5, ['6']=6, ['7']=7, ['8']=8, ['9']=9,
    ['a']=10, ['b']=11, ['c']=12, ['d']=13, ['e']=14, ['f']=15,
    ['A']=10, ['B']=11, ['C']=12, ['D']=13, ['E']=14, ['F']=15,
  };
  int8_t val = lookup[(unsigned char)c];
  return val ? val : (c == '0' ? 0 : -1);
}

char hex_char(int v) {
  return "0123456789abcdef"[v & 0x0f];
}

uint64_t hash_key(const char *key, size_t len) {
  uint64_t hash = 14695981039346656037ULL;
  size_t i = 0;
  
  for (; i + 8 <= len; i += 8) {
    uint64_t word;
    memcpy(&word, key + i, 8);
    hash ^= word;
    hash *= 1099511628211ULL;
  }
  
  for (; i < len; i++) {
    hash ^= (uint8_t)key[i];
    hash *= 1099511628211ULL;
  }
  
  return hash;
}

int is_typescript_file(const char *filename) {
  if (filename == NULL) return 0;
  size_t len = strlen(filename);
  if (len < 3) return 0;
  
  const char *ext = filename + len;
  while (ext > filename && *(ext - 1) != '.' && *(ext - 1) != '/') ext--;
  if (ext == filename || *(ext - 1) != '.') return 0;
  ext--;
  
  return (strcmp(ext, ".ts") == 0 || strcmp(ext, ".mts") == 0 || strcmp(ext, ".cts") == 0);
}

static bool has_js_extension(const char *filename) {
  const char *dot = strrchr(filename, '.');
  if (!dot) return false;
  for (const char *const *ext = js_extensions; *ext; ext++) {
    if (strcmp(dot, *ext) == 0) return true;
  }
  return false;
}

char *resolve_js_file(const char *filename) {
  extern bool esm_is_url(const char *path);
  if (!filename) return NULL;
  if (esm_is_url(filename)) return strdup(filename);
  
  struct stat st;
  if (stat(filename, &st) == 0) {
    if (S_ISREG(st.st_mode)) return strdup(filename);
    if (!S_ISDIR(st.st_mode)) return NULL;

    size_t len = strlen(filename);
    int has_slash = (len > 0 && filename[len - 1] == '/');
    char *index_path = try_oom(len + 10 + (has_slash ? 0 : 1));
    sprintf(index_path, "%s%sindex.js", filename, has_slash ? "" : "/");
    return index_path;
  }
  
  if (has_js_extension(filename)) return NULL;
  size_t base_len = strlen(filename);
  
  for (const char *const *ext = js_extensions; *ext; ext++) {
    size_t ext_len = strlen(*ext);
    char *test_path = try_oom(base_len + ext_len + 1);
    
    memcpy(test_path, filename, base_len);
    memcpy(test_path + base_len, *ext, ext_len + 1);
    
    if (stat(test_path, &st) == 0 && S_ISREG(st.st_mode)) {
      return test_path;
    } free(test_path);
  }
  
  return NULL;
}

void *try_oom(size_t size) {
  void *p = malloc(size);
  if (!p) {
    crfprintf(stderr, msg.oom_fatal);
    exit(EXIT_FAILURE);
  } return p;
}

void cstr_free(cstr_buf_t *buf) {
  if (buf->heap) free(buf->heap);
}

char *cstr_init(cstr_buf_t *buf, char *stack, size_t stack_size, const char *src, size_t len) {
  if (len < stack_size) {
    buf->ptr = stack;
    buf->heap = NULL;
  } else {
    buf->heap = malloc(len + 1);
    if (!buf->heap) return NULL;
    buf->ptr = buf->heap;
  }
  memcpy(buf->ptr, src, len);
  buf->ptr[len] = '\0';
  return buf->ptr;
}