#include <liballoc.h>
#include <list.h>
#include <m/fs_desc_buffer.h>
#include <minmax.h>
#include <printf.h>
#include <process.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <str_status.h>
#include <string.h>
#include <system.h>
#include <terminal_cursor.h>

#define LINE_BUFFER_MAX 1024
#define TOKEN_MAX       64
#define PROMPT          "ce $ "

struct token {
  struct list_node_link tokens_link;
  char buffer[TOKEN_MAX];
};

static int e_pid;
static int e_pgid;

static void putch (char ch) { mail_send (e_pgid, &ch, 1); }
void putchar_ (char ch) { putch (ch); }

static bool tokenize_line (void* ctx, const char* start, size_t len) {
  struct list_node_link** head = ctx;

  struct token* token = malloc (sizeof (*token));

  if (token == NULL)
    return false;

  memset (token, 0, sizeof (*token));
  memcpy (token->buffer, start, min (sizeof (token->buffer) - 1, len));

  list_append ((*head), &token->tokens_link);

  return true;
}

static void free_tokens (struct list_node_link* tokens) {
  struct list_node_link *token_link, *token_tmp_link;
  list_foreach (tokens, token_link, token_tmp_link) {
    struct token* token = list_entry (token_link, struct token, tokens_link);
    list_remove (tokens, &token->tokens_link);
    free (token);
  }
}

static void cmd_echo (struct list_node_link* tokens) {
  struct list_node_link *token_link, *token_tmp_link;
  list_foreach (tokens, token_link, token_tmp_link) {
    struct token* token = list_entry (token_link, struct token, tokens_link);

    printf ("%s ", token->buffer);
  }
}

static void cmd_cat (struct list_node_link* tokens) {
  if (tokens == NULL) {
    printf ("ERROR: no file paths provided\n");
    return;
  }

  struct fs_desc_buffer desc;

  struct list_node_link *token_link, *token_tmp_link;
  list_foreach (tokens, token_link, token_tmp_link) {
    struct token* token = list_entry (token_link, struct token, tokens_link);
    int ret;

    ret = open (token->buffer);

    if (ret < 0) {
      printf ("ERROR opening %s: %s\n", token->buffer, str_status[-ret]);
      continue;
    }

    describe (token->buffer, &desc);

    if (desc.type != FS_FILE)
      goto close1;

    char* buffer = malloc (desc.size + 1);

    if (buffer == NULL)
      goto close1;

    memset (buffer, 0, desc.size + 1);

    ret = read (token->buffer, 0, (uint8_t*)buffer, desc.size);

    if (ret < 0) {
      printf ("ERROR reading%s: %s\n", token->buffer, str_status[-ret]);
      goto close1;
    }

    printf ("%s\n", buffer);

  close1:
    if (buffer != NULL)
      free (buffer);

    close (token->buffer);
  }
}

static void cmd_help (struct list_node_link* tokens) {
  (void)tokens;

  printf ("Available commands:\n");
  printf ("\techo <word1> <word2> <word3> ...\n");
  printf ("\thelp\n");
  printf ("\tcat <file path>\n");
}

static void exec_tokens (struct list_node_link* tokens) {
  struct token* cmd_token = list_entry (tokens, struct token, tokens_link);

  if (strcmp (cmd_token->buffer, "echo") == 0) {
    cmd_echo (tokens->next);
  } else if (strcmp (cmd_token->buffer, "help") == 0) {
    cmd_help (tokens->next);
  } else if (strcmp (cmd_token->buffer, "cat") == 0) {
    cmd_cat (tokens->next);
  } else {
    printf ("ERROR: unknown command '%s'\n", cmd_token->buffer);
  }
}

static void exec_line (const char* line) {
  struct list_node_link* tokens = NULL;

  strtokenize (line, ' ', &tokens, &tokenize_line);

  if (tokens != NULL)
    exec_tokens (tokens);

  free_tokens (tokens);
}

void app_main (void) {
  e_pid = get_exec_pid ();
  e_pgid = get_procgroup (e_pid);

  size_t line_cursor = 0;
  char line_buffer[LINE_BUFFER_MAX + 1];
  memset (line_buffer, 0, sizeof (line_buffer));

  for (;;) {
    printf (PROMPT);

    char ch = 0;
    for (;;) {
      mail_receive (&ch, 1);

      if (ch == '\n')
        break;

      if (line_cursor < LINE_BUFFER_MAX) {
        line_buffer[line_cursor++] = ch;
        printf ("%c", ch);
      }
    }

    printf ("\n");
    exec_line (line_buffer);

    line_cursor = 0;
    memset (line_buffer, 0, sizeof (line_buffer));
    printf ("\n");
  }
}