#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/wait.h>
#include <sys/reboot.h>
#include <sys/ioctl.h>
#include <dirent.h>
#include <fcntl.h>
#include <stdbool.h>

#include "para.h"
#include "builtin.h"


static bool verbose = false;

int parse_cmd(char *cmd, char *argv[]) {
    int argc = 0;
    char *ptr = cmd;
    char *token_start;
    char quote_char = 0;

    while (*ptr) {
        while (*ptr == ' ' && quote_char == 0) ptr++;
        if (*ptr == '\0') break;

        token_start = ptr; 
        char *write_ptr = ptr;

        while (*ptr) {
            if (quote_char == 0 && *ptr == ' ') {
                ptr++; 
                break;
            }

            if (*ptr == '"' || *ptr == '\'') {
                if (quote_char == *ptr) quote_char = 0;
                else if (quote_char == 0) quote_char = *ptr;
                else *write_ptr++ = *ptr;
            } 
            else {
                *write_ptr++ = *ptr;
            }
            
            ptr++;
        }
        
        *write_ptr = '\0';
        argv[argc++] = token_start;

        if (argc >= MAX_ARGS - 1) break;
    }
    
    argv[argc] = NULL;
    return argc;
}

// 반환값: 1(처리함), 0(파이프 없음)
int handle_pipe(char *argv[]) {
    int pipe_idx = -1;

    for (int i = 0; argv[i] != NULL; i++) {
        if (strcmp(argv[i], "|") == 0) {
            pipe_idx = i;
            break;
        }
    }

    if (pipe_idx == -1) return 0;

    argv[pipe_idx] = NULL;
    char **left_cmd = &argv[0];
    char **right_cmd = &argv[pipe_idx + 1];

    if (right_cmd[0] == NULL) {
        printf("gmsh: syntax error near unexpected token `|'\n");
        return 1; 
    }

    int fds[2];
    if (pipe(fds) == -1) {
        perror("pipe");
        return 1;
    }

    pid_t pid1 = fork();
    if (pid1 == 0) {
        close(fds[0]);   
        dup2(fds[1], STDOUT_FILENO); 
        close(fds[1]);   

        handle_redirection((const char**) left_cmd);
        execvp(left_cmd[0], left_cmd);
        perror("execvp left");
        exit(1);
    }

    pid_t pid2 = fork();
    if (pid2 == 0) {
        close(fds[1]);   
        dup2(fds[0], STDIN_FILENO);
        close(fds[0]);   

        if (handle_pipe(right_cmd) == 1) {
            exit(0);
        } 
        else {
            handle_redirection((const char**) right_cmd);
            execvp(right_cmd[0], right_cmd);
            perror("execvp right");
            exit(1);
        }
    }

    close(fds[0]);
    close(fds[1]);

    waitpid(pid1, NULL, 0);
    waitpid(pid2, NULL, 0);

    return 1; // 처리 완료
}

void run_shell() {
    char cmd_buf[MAX_CMD_LEN];
    char *args[MAX_ARGS];
    char cwd[1024];
    
    while (1) {
        if (getcwd(cwd, sizeof(cwd))) printf("\033[1;32mgmsh\033[0m:%s$ ", cwd);
        else printf("gmsh:$ ");
        fflush(stdout);

        if (!fgets(cmd_buf, sizeof(cmd_buf), stdin)) break;
        cmd_buf[strcspn(cmd_buf, "\n")] = 0;
        if (strlen(cmd_buf) == 0) continue;

        // int argc = 0;
        // args[argc] = strtok(cmd_buf, " ");
        // while (args[argc] != NULL && argc < MAX_ARGS - 1) args[++argc] = strtok(NULL, " ");

        int argc = parse_cmd(cmd_buf, args);

        if (argc == 0) continue;

        if (handle_pipe(args)) {
            continue;
        }

        if (verbose) {
             printf("[debug] argc: %d\n", argc);
             for(int i=0; i<argc; i++) printf("[debug] argv[%d]: '%s'\n", i, args[i]);
        }

        if (strcmp(args[0], "exit") == 0) exit(0);
        else if (strcmp(args[0], "ls") == 0) cmd_ls(args[1]);
        else if (strcmp(args[0], "cd") == 0) cmd_cd(args[1]);
        else if (strcmp(args[0], "pwd") == 0) cmd_pwd();
        // else if (strcmp(args[0], "cat") == 0) cmd_cat(argc, (const char**) args);
        // else if (strcmp(args[0], "proc") == 0) cmd_proc();
        // else if (strcmp(args[0], "echo") == 0) cmd_echo(argc, (const char**) args);

        else if (strcmp(args[0], "size") == 0) cmd_size();
        else if (strcmp(args[0], "resize") == 0){
            if(argc != 3){
                printf("Usage: resize <rows> <cols>\n");
            }
            else cmd_resize(args[1], args[2]);
        }

        else if (strcmp(args[0], "poweroff") == 0) cmd_poweroff();
        else if (strcmp(args[0], "reboot") == 0) cmd_reboot();
        else if (strcmp(args[0], "help") == 0) cmd_help();
        else {
            pid_t pid = fork();

            // if (pid == 0) {
            //     execvp(args[0], args);
            //     printf("%s: command not found\n", args[0]);
            //     exit(1);
            // } else wait(NULL);
	    
            if (pid == 0) {
                handle_redirection((const char**) args);
                execvp(args[0], args);

                fprintf(stderr, "%s: command not found\n", args[0]);
                exit(127);
            } else if (pid > 0) {
                int status;

                if (verbose) {
                    printf("[debug] Spawned child PID: %d\n", pid);
                }

                waitpid(pid, &status, 0);

                if (verbose) {
                    if (WIFEXITED(status)) {
                        printf("[debug] Process %d exited with code %d\n", pid, WEXITSTATUS(status));
                    } else if (WIFSIGNALED(status)) {
                        printf("[debug] Process %d killed by signal %d\n", pid, WTERMSIG(status));
                    }
                }
            } else {
                perror("fork");
            }
        }
    }
}

int main(int argc, char** argv) {
    printf("GMSH (GMS Minimal SHell) v1.0 initialized.\n");

    int opt;
    while ((opt = getopt(argc, argv, "v")) != -1) {
        switch (opt) {
            case 'v':
                verbose = 1;
                printf("[gmsh] Verbose mode enabled.\n");
                break;
            default:
                fprintf(stderr, "Usage: %s [-v]\n", argv[0]);
                exit(1);
        }
    }
    
    run_shell();
    return 0;
}