#include "common/common.h"

void readline(char* buf, uint32_t lim) {
  uint32_t idx = 0;
  while (1) {
    char c;
    if (idx == lim) {
      printf("\n");
      break;
    }
    if (read(1, 1, &c)) {
      if (c == '\n') {
        write(1, 0, &c);
        break;
      } else if (c == '\b') {
          if (idx > 0) {
          buf[--idx] = 0;
          write(1, 0, &c);
        }
      } else if (c == 0) {
        continue;
      } else {
        buf[idx++] = c;
        write(1, 0, &c);
      }
    }
  }
}

typedef enum {
  Normal,
  StringLiteral,
  Escaped
} ParseState;

int main(int argc, char** argv, char** envp) {
  // XOSH - The XnoeOS Shell
  // XoSH is going to be a simple shell that can be used to execute programs.

  printf("Welcome to %s!\n\n", argv[0]);

  printf("Environment:\n");
  for (int i=0; envp[i]; i++)
    printf("- %s\n", envp[i]);
  printf("\n");

  while (1) {
    printf("\x1b[0m# ");
    char input[128];
    memset(input, 0, 128);
    readline(input, 128);

    // Parse the input
    char* result[32];
    uint32_t ridx=0;
    memset(result, 0, 128);
    char c;
    uint32_t idx=0;
    char* lp = input;
    ParseState s = Normal;
    while (c=input[idx++]) {
      switch (s) {
        case Normal:
          switch (c) {
            case '"':
              s = StringLiteral;
              break;
            case '\\':
              s = Escaped;
              break;
            case ' ':
              input[idx-1] = 0;
              result[ridx++] = lp;
              lp = (char*)(input+idx);
              break;
            default:
              break;
          }
          break;
        case StringLiteral:
          if (c == '"') {
            s = Normal;
          }
          break;
        case Escaped:
          break;
        default:
          break;
      }
    }
    result[ridx++] = lp;

    if (ridx > 0) {
      char* programName = result[0];
      if (exists(programName)) {
        char** argv = result;
        uint32_t program = fopen(programName);
        uint32_t e = execv(program, argv);
        printf("\nExit code: %d\n\n", e);
      } else if (strcmp(result[0], "set")) {
        setenv(result[1], result[2]);
      } else {
        printf("No such executable file: `%s`\n\n", programName);
      }
    }
  }
}