#include <efi.h>
#include "commands.h"
#include "string_utils.h"
#include "memory.h"

#define SAFE_PRINT(Boot, ...)                           \
    do {                                                \
        if ((Boot) != NULL && (Boot)->print != NULL) {  \
            (Boot)->print(__VA_ARGS__);                 \
        }                                               \
    } while (0)

// Forward declarations
static void cmd_shutdown(BootInfo *Boot, CHAR16 *Args);
static void cmd_help(BootInfo *Boot, CHAR16 *Args);
static void cmd_man(BootInfo *Boot, CHAR16 *Args);
static void cmd_clear(BootInfo *Boot, CHAR16 *Args);
static void cmd_about(BootInfo *Boot, CHAR16 *Args);
static void cmd_mem(BootInfo *Boot, CHAR16 *Args);

// Command registry
static Command commands[] = {
    {
        L"shutdown",
        L"Shutdown the system",
        L"Usage: shutdown\n\r  Initiates a system shutdown using UEFI runtime services.",
        cmd_shutdown
    },
    {
        L"help",
        L"Display available commands",
        L"Usage: help\n\r  Lists all available commands with brief descriptions.",
        cmd_help
    },
    {
        L"man",
        L"Display manual page for a command",
        L"Usage: man <command>\n\r  Shows detailed help for the specified command.",
        cmd_man
    },
    {
        L"clear",
        L"Clear the screen",
        L"Usage: clear\n\r  Clears the console screen.",
        cmd_clear
    },
    {
        L"about",
        L"Display system information",
        L"Usage: about\n\r  Shows information about this operating system.",
        cmd_about
    },
    {
        L"mem",
        L"Display memory statistics",
        L"Usage: mem\n\r  Shows physical memory, heap, and paging information.",
        cmd_mem
    },
    {NULL, NULL, NULL, NULL}  // Sentinel
};

static void request_shutdown(BootInfo *Boot)
{
    if (Boot == NULL) {
        return;
    }

    if (Boot->shutdown != NULL) {
        Boot->shutdown();
        return;
    }

    if (Boot->SystemTable != NULL &&
        Boot->SystemTable->RuntimeServices != NULL &&
        Boot->SystemTable->RuntimeServices->ResetSystem != NULL) {
        Boot->SystemTable->RuntimeServices->ResetSystem(
            EfiResetShutdown, EFI_SUCCESS, 0, NULL);
        return;
    }

    SAFE_PRINT(Boot, L"Shutdown service unavailable.\n\r");
}

static void cmd_shutdown(BootInfo *Boot, CHAR16 *Args)
{
    (void)Args;  // Unused
    SAFE_PRINT(Boot, L"Shutting down...\n\r");
    request_shutdown(Boot);
}

static void cmd_help(BootInfo *Boot, CHAR16 *Args)
{
    (void)Args;  // Unused
    show_help(Boot);
}

static void cmd_man(BootInfo *Boot, CHAR16 *Args)
{
    UINTN i = 0;
    
    if (Args == NULL || Args[0] == L'\0') {
        SAFE_PRINT(Boot, L"Usage: man <command>\n\r");
        SAFE_PRINT(Boot, L"Try 'help' for a list of available commands.\n\r");
        return;
    }

    trim_spaces_inplace(Args);
    
    for (i = 0; commands[i].name != NULL; i++) {
        if (ascii_streq_ci(Args, commands[i].name)) {
            SAFE_PRINT(Boot, L"\n\r");
            SAFE_PRINT(Boot, L"NAME\n\r");
            SAFE_PRINT(Boot, L"  %s - %s\n\r\n\r", commands[i].name, commands[i].description);
            SAFE_PRINT(Boot, L"DESCRIPTION\n\r");
            SAFE_PRINT(Boot, L"  %s\n\r", commands[i].usage);
            SAFE_PRINT(Boot, L"\n\r");
            return;
        }
    }

    SAFE_PRINT(Boot, L"No manual entry for '%s'\n\r", Args);
    SAFE_PRINT(Boot, L"Try 'help' for a list of available commands.\n\r");
}

static void cmd_clear(BootInfo *Boot, CHAR16 *Args)
{
    EFI_STATUS Status;
    (void)Args;  // Unused
    
    if (Boot != NULL && Boot->clear_screen != NULL) {
        Status = Boot->clear_screen();
        if (EFI_ERROR(Status)) {
            SAFE_PRINT(Boot, L"Failed to clear screen: %r\n\r", Status);
        }
    } else {
        SAFE_PRINT(Boot, L"Clear screen function unavailable.\n\r");
    }
}

static void cmd_about(BootInfo *Boot, CHAR16 *Args)
{
    (void)Args;  // Unused
    
    SAFE_PRINT(Boot, L"\n\r");
    SAFE_PRINT(Boot, L"================================================\n\r");
    SAFE_PRINT(Boot, L"  Simple UEFI Operating System\n\r");
    SAFE_PRINT(Boot, L"================================================\n\r");
    SAFE_PRINT(Boot, L"\n\r");
    SAFE_PRINT(Boot, L"A minimal bootable UEFI operating system written in C.\n\r");
    SAFE_PRINT(Boot, L"\n\r");
    SAFE_PRINT(Boot, L"Features:\n\r");
    SAFE_PRINT(Boot, L"  - UEFI Boot\n\r");
    SAFE_PRINT(Boot, L"  - Console I/O\n\r");
    SAFE_PRINT(Boot, L"  - ELF64 Kernel Loader\n\r");
    SAFE_PRINT(Boot, L"  - Memory Management (PMM + Heap)\n\r");
    SAFE_PRINT(Boot, L"  - Interactive Command Interface\n\r");
    SAFE_PRINT(Boot, L"\n\r");
    SAFE_PRINT(Boot, L"Type 'help' for available commands.\n\r");
    SAFE_PRINT(Boot, L"\n\r");
}

static void cmd_mem(BootInfo *Boot, CHAR16 *Args)
{
    (void)Args;
    memory_print_stats(Boot);
}

void show_help(BootInfo *Boot)
{
    UINTN i = 0;
    UINTN max_len = 0;
    UINTN name_len = 0;
    UINTN padding = 0;
    
    SAFE_PRINT(Boot, L"\n\r");
    SAFE_PRINT(Boot, L"Available commands:\n\r");
    SAFE_PRINT(Boot, L"\n\r");
    
    // Find longest command name for formatting
    for (i = 0; commands[i].name != NULL; i++) {
        name_len = 0;
        while (commands[i].name[name_len] != L'\0') {
            name_len++;
        }
        if (name_len > max_len) {
            max_len = name_len;
        }
    }
    
    for (i = 0; commands[i].name != NULL; i++) {
        SAFE_PRINT(Boot, L"  %s", commands[i].name);
        
        // Add padding
        name_len = 0;
        while (commands[i].name[name_len] != L'\0') {
            name_len++;
        }
        for (padding = 0; padding < (max_len - name_len + 2); padding++) {
            SAFE_PRINT(Boot, L" ");
        }
        
        SAFE_PRINT(Boot, L"- %s\n\r", commands[i].description);
    }
    
    SAFE_PRINT(Boot, L"\n\r");
    SAFE_PRINT(Boot, L"For detailed help on a command, type: man <command>\n\r");
    SAFE_PRINT(Boot, L"\n\r");
}

void execute_command(BootInfo *Boot, CHAR16 *Input)
{
    CHAR16 *cmd_start = NULL;
    CHAR16 *args_start = NULL;
    UINTN i = 0;
    
    if (Boot == NULL || Input == NULL) {
        return;
    }

    trim_spaces_inplace(Input);
    
    if (Input[0] == L'\0') {
        return;
    }

    // Split command and arguments
    cmd_start = Input;
    args_start = Input;
    
    // Find first space
    while (*args_start != L'\0' && !is_space16(*args_start)) {
        args_start++;
    }
    
    // If we found a space, null-terminate command and advance to args
    if (*args_start != L'\0') {
        *args_start = L'\0';
        args_start++;
        
        // Skip leading spaces in args
        while (*args_start != L'\0' && is_space16(*args_start)) {
            args_start++;
        }
    }
    
    // Search for command
    for (i = 0; commands[i].name != NULL; i++) {
        if (ascii_streq_ci(cmd_start, commands[i].name)) {
            commands[i].handler(Boot, args_start);
            return;
        }
    }

    // Command not found
    SAFE_PRINT(Boot, L"Unknown command: %s\n\r", cmd_start);
    SAFE_PRINT(Boot, L"Type 'help' for a list of available commands.\n\r");
}