#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include "option.h"
#include "util/versie.h"
#include "util/debug.h"


/* static void debug_argv(int argc, char **argv) {
  fprintf(stderr, "argv: <");
  for (int i = 0; i < argc; i++) {
    if (i != 0) fputc(',', stderr);
    fprintf(stderr, "'%s'", argv[i]);
  }
  fprintf(stderr, ">\n");
} */

char** option_parse(int argc, char **argv, const struct option_spec *speclist) {
  // fill table of specs
  const struct option_spec *spectable[256] = {0};
  for (const struct option_spec *spec = speclist; spec->kind != OPTSPECKIND_END; spec++) {
    if (spectable[(uint8_t)spec->optc] != NULL) {
      fprintf(stderr, "option_parse: dubbele specs\n");
      abort();
    }
    spectable[(uint8_t)spec->optc] = spec;

    if (spec->kind == OPTSPECKIND_WITHARG) {
      *spec->spec_sub.witharg.dst = NULL;
    }
  }

  // option, option argument, or '--'.
  bool *is_option = calloc(argc, 1);

  // parse options
  int last_option_index = 0;  // index of last option argument, treating '--' as option arg
  int npos_before_opts = 0;  // number of positional arguments before last_option_index
  int opti;
  for (opti = 1; opti < argc; opti++) {
    DEBUG("opti = %d\n", opti);

    if (argv[opti][0] != '-') continue;  // skip non-options

    is_option[opti] = true;

    // count an option argument even if it's '--'
    npos_before_opts += opti - (last_option_index + 1);
    last_option_index = opti;

    if (strcmp(argv[opti], "--") == 0) break;  // but don't try to parse '--'

    bool skip_next_argument = false;

    for (int j = 1; argv[opti][j]; j++) {
      const struct option_spec *spec = spectable[(uint8_t)argv[opti][j]];
      if (!spec) {
        fprintf(stderr, "%s: Ongeldige optie: -%c\n", argv[0], argv[opti][j]);
        exit(1);
      }

      switch (spec->kind) {
        case OPTSPECKIND_SETBOOL:
          *spec->spec_sub.setbool.ptr = true;
          break;

        case OPTSPECKIND_CALL:
          spec->spec_sub.call.fun();
          break;

        case OPTSPECKIND_CALLP:
          spec->spec_sub.callp.fun(spec->spec_sub.callp.data);
          break;

        case OPTSPECKIND_WITHARG:
          if (argv[opti][j+1] != '\0') {
            fprintf(stderr, "%s: Optie -%c heeft een argument nodig, maar is niet de laatste op rij\n", argv[0], argv[opti][j]);
            exit(1);
          }

          if (opti + 1 < argc) {
            char **dst = spec->spec_sub.witharg.dst;
            if (*dst) free(*dst);  // override any previous value

            const size_t arglen = strlen(argv[opti+1]);
            *dst = malloc(arglen + 1);
            memcpy(*dst, argv[opti+1], arglen + 1);

            skip_next_argument = true;
          } else {
            fprintf(stderr, "%s: Optie -%c heeft een argument nodig\n", argv[0], argv[opti][j]);
            exit(1);
          }
          break;

        case OPTSPECKIND_HELPUSAGE:
          printf(spec->spec_sub.helpusage.usagestr, argv[0]);
          exit(0);

        case OPTSPECKIND_VERSION:
          drukkedoos_print_versie(stdout);
          exit(0);

        case OPTSPECKIND_END: abort(); // unreachable
      }
    }

    if (skip_next_argument) {
      // skip next argument, but mark it as an option
      last_option_index = ++opti;
      is_option[opti] = true;
    }
  }

  DEBUG("last_option_index=%d npos_before_opts=%d\n", last_option_index, npos_before_opts);

  // debug_argv(argc, argv);

  // collect positional arguments that need to be reshuffled
  char *posargs[npos_before_opts];
  for (int i = 1, posi = 0; i < last_option_index; i++) {
    if (!is_option[i]) posargs[posi++] = argv[i];
  }

  // move option arguments to the beginning
  int noptargs = 0;
  for (int readi = 1; readi <= last_option_index; readi++) {
    if (is_option[readi]) {
      if (readi > noptargs + 1) argv[noptargs + 1] = argv[readi];
      noptargs++;
    }
  }

  // debug_argv(argc, argv);

  // write positional arguments after the option arguments
  memcpy(argv + 1 + noptargs, posargs, npos_before_opts * sizeof(char*));

  // debug_argv(argc, argv);

  free(is_option);

  return argv + 1 + noptargs;
}