#include "monitor/monitor.h"
#include "monitor/expr.h"
#include "monitor/watchpoint.h"
#include "nemu.h"

#include <stdlib.h>
#include <readline/readline.h>
#include <readline/history.h>

#include <stdexcept>
#include <rlib/stdio.hpp>
using namespace rlib::literals;
using rlib::println;
using rlib::printfln;
using rlib::string;

#include <sstream>
#include <iomanip>

#include <rlib/3rdparty/prettyprint.hpp>
using namespace rlib::_3rdparty::std;

void cpu_exec(uint64_t);

/* We use the `readline' library to provide more flexibility to read from stdin. */
char* rl_gets() {
  static char *line_read = NULL;

  if (line_read) {
    free(line_read);
    line_read = NULL;
  }

  line_read = readline("(nemu) ");

  if (line_read && *line_read) {
    add_history(line_read);
  }

  return line_read;
}

static int cmd_c(char *args) {
  cpu_exec(-1);
  return 0;
}

static int cmd_n(char *args) {
  cpu_exec(1);
  return 0;
}

static int cmd_info(char *args);
static int cmd_x(char *args);
static int cmd_w(char *args);
static int cmd_p(char *args);
static int cmd_d(char *args);

static int cmd_q(char *args) {
  return -1;
}

static int cmd_help(char *args);

static struct {
  const char *name;
  const char *description;
  int (*handler) (char *);
} cmd_table [] = {
  { "help", "Display informations about all supported commands", cmd_help },
  { "c", "Continue the execution of the program", cmd_c },
  { "n", "= GDB `n`", cmd_n },
  { "info", "= GDB `info`, supporting `info r` / `info w`", cmd_info },
  { "x", "x <bytes> <startAddr or expr>, dump memory content.", cmd_x },
  { "w", "w <expr>, add watchpoint for $expr", cmd_w },
  { "p", "p <expr>, show value of $expr", cmd_p },
  { "d", "d <watchpoint id>, delete watchpoint by id", cmd_d },
  { "q", "Exit NEMU", cmd_q },

  /* TODO: Add more commands */

};

#define NR_CMD (sizeof(cmd_table) / sizeof(cmd_table[0]))

static int cmd_help(char *args) {
  /* extract the first argument */
  char *arg = strtok(NULL, " ");
  int i;

  if (arg == NULL) {
    /* no argument given */
    for (i = 0; i < NR_CMD; i ++) {
      printf("%s - %s\n", cmd_table[i].name, cmd_table[i].description);
    }
  }
  else {
    for (i = 0; i < NR_CMD; i ++) {
      if (strcmp(arg, cmd_table[i].name) == 0) {
        printf("%s - %s\n", cmd_table[i].name, cmd_table[i].description);
        return 0;
      }
    }
    printf("Unknown command '%s'\n", arg);
  }
  return 0;
}

void ui_mainloop(int is_batch_mode) {
  if (is_batch_mode) {
    cmd_c(NULL);
    return;
  }

  for (char *str; (str = rl_gets()) != NULL; ) {
    char *str_end = str + strlen(str);

    /* extract the first token as the command */
    char *cmd = strtok(str, " ");
    if (cmd == NULL) { continue; }

    /* treat the remaining string as the arguments,
     * which may need further parsing
     */
    char *args = cmd + strlen(cmd) + 1;
    if (args >= str_end) {
      args = NULL;
    }

#ifdef HAS_IOE
    extern void sdl_clear_event_queue(void);
    sdl_clear_event_queue();
#endif

    int i;
    for (i = 0; i < NR_CMD; i ++) {
      if (strcmp(cmd, cmd_table[i].name) == 0) {
        try {
          if (cmd_table[i].handler(args) < 0) { return; }
        }
        catch(std::exception &e) {
          println("Exception caught:", e.what());
        }
        break;
      }
    }

    if (i == NR_CMD) { printf("Unknown command '%s'\n", cmd); }
  }
}

// 3rdparty prettyprint will print rlib::string as array. Let's convert it to normal string.
std::string dumpReg(uint32_t val) {
  return string("{}{}[32b=0x{}{}, {}L16b=0x{}]{}").format(std::setfill('0'), std::setw(8), std::hex, val, std::setw(4), (uint16_t)val, std::dec);
}
auto dumpMem(uint32_t begin_addr, uint64_t size) {
  std::stringstream res;
  res << std::hex;
  for(uint64_t cter = 0; cter < size; cter += 4) {
    if(cter % 32 == 0) {
      res << '\n';
      res << "0x" << std::setfill('0') << std::setw(8) << begin_addr + cter << ": ";
    }
    res << std::setfill('0') << std::setw(8) << vaddr_read(begin_addr + cter, 4) << ' ';
  }
  res << std::dec;
  return res.str();
}

static int cmd_info(char *_args) {
  if(_args == NULL)
    throw std::runtime_error("Usage: info <what>");
  if(string(_args).strip() == "r") {
    println("Registers:");
    printfln("%eax={}, %ebx={}, %ecx={}, %edx={}", dumpReg(cpu.eax), dumpReg(cpu.ebx), dumpReg(cpu.ecx), dumpReg(cpu.edx));
    printfln("%esp={}, %ebp={}, %esi={}, %edi={}", dumpReg(cpu.esp), dumpReg(cpu.ebp), dumpReg(cpu.esi), dumpReg(cpu.edi));
    printfln("%eip={}, CF/OF/SF/ZF={}/{}/{}/{}", dumpReg(cpu.eip), cpu_eflags::get<cpu_eflags::CF>(), 
            cpu_eflags::get<cpu_eflags::OF>(), cpu_eflags::get<cpu_eflags::SF>(), cpu_eflags::get<cpu_eflags::ZF>());
  }
  else if(string(_args).strip() == "w") {
    println("Watchpoints:");
    println(watchpoints);
  }
 return 0;
}

static int cmd_x(char *_args) {
  if(_args == NULL)
    throw std::runtime_error("Usage: x <size> <startAddr/expr>");
  auto args = string(_args).strip().split();
  if(args.size() != 2)
    throw std::runtime_error("Usage: x <size> <startAddr/expr>");
  
  uint32_t beginAddr = evaluate_expr(args[1]);
  println(dumpMem(beginAddr, args[0].as<uint64_t>()));
  return 0;
}

static int cmd_w(char *_args) {
  if(_args == NULL)
    throw std::invalid_argument("w <expr>");
  
  watchpoints.emplace_front(std::string(_args), ++max_watchpoint_id);
  auto iter = watchpoints.begin(); // not thread-safe.
  rlib::println("Add watchpoint:", *iter);
  return 0;
}

static int cmd_p(char *_args) {
  if(_args == NULL)
    throw std::invalid_argument("p <expr>");

  auto result = evaluate_expr(_args);
  rlib::printfln("$ = {} = 0x{}{}{}", result, std::hex, result, std::dec);
  return 0;
}

static int cmd_d(char *_args) {
  if(_args == NULL)
    throw std::invalid_argument("d <wp id>");

  auto to_remove = rlib::string(_args).as<int>();
  
  watchpoints.remove_if([&](auto &wp){
    return wp.id == to_remove;
  });
  return 0;
}
