// Copyright (c) 2024 Cesanta Software Limited
//
// Utility that generates packed filesystem C file compatible with the
// Mongoose Network Library, https://github.com/cesanta/mongoose
//
// Usage:
//    node pack.js FILE[:DESTINATION[:gzip]] ...

const fs = require('fs');
const zlib = require('zlib');
const argv = process.argv.slice(2);

// Convert each command-line arguments into [ DATA_ARRAY, STRUCT_INITIALIZER ]
const entries = argv.map(function(filename, i) {
  const parts = filename.split(':');
  const stat = fs.statSync(parts[0]);
  const data = fs.readFileSync(parts[0], null);
  let bytes = Array.from(data);
  let destination = (parts[1] || parts[0]).replace(/^\.+[\/\\]*/, '');
  if (parts[2] == 'gzip') {
    bytes = Array.from(zlib.gzipSync(data));
    destination += '.gz';
  }
  
  // concat(0) appends trailing 0, in order to make any file an asciz string
  return [
    `static const unsigned char v${i}[] = {${bytes.concat(0).join(',')}};`,
    `  {"/${destination}", v${i}, sizeof(v${i}) - 1, ${parseInt(stat.mtimeMs / 1000)}}`,
  ];
});

process.stdout.write(`// DO NOT EDIT. This file is generated using this command:
// ${process.argv.join(' ')}

#include <stddef.h>
#include <string.h>
#include <time.h>

#if defined(__cplusplus)
extern "C" {
#endif

const char *mg_unlist(size_t no);
const char *mg_unpack(const char *, size_t *, time_t *);

#if defined(__cplusplus)
}
#endif

${entries.map(x => x[0]).join('\n\n')}

static const struct packed_file {
  const char *name;
  const unsigned char *data;
  size_t size;
  time_t mtime;
} packed_files[] = {
${entries.map(x => x[1]).join(',\n')},
  {NULL, NULL, 0, 0}
};

static int scmp(const char *a, const char *b) {
  while (*a && (*a == *b)) a++, b++;
  return *(const unsigned char *) a - *(const unsigned char *) b;
}

const char *mg_unlist(size_t no) {
  return packed_files[no].name;
}

const char *mg_unpack(const char *name, size_t *size, time_t *mtime) {
  const struct packed_file *p;
  for (p = packed_files; p->name != NULL; p++) {
    if (scmp(p->name, name) != 0) continue;
    if (size != NULL) *size = p->size;
    if (mtime != NULL) *mtime = p->mtime;
    return (const char *) p->data;
  }
  return NULL;
};
`);