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#include <panic.h>

#include <list.h>

#include <arch.h>

#include <func.h>

#include <macros.h>

#define MAX_CMDLINE 256

/** Simple kernel console.

 *

 * The console is realized by kernel thread kconsole.

 * It doesn't understand any commands on its own, but

 * makes it possible for other kernel subsystems to

 * register their own commands.

 */

/** Locking.

 *

 * There is a list of cmd_info_t structures. This list

 * is protected by cmd_lock spinlock. Note that specially

 * the link elements of cmd_info_t are protected by

 * this lock.

 *

 * Each cmd_info_t also has its own lock, which protects

 * all elements thereof except the link element.

 *

 * cmd_lock must be acquired before any cmd_info lock.

 * When locking two cmd info structures, structure with

 * lower address must be locked first.

 */

spinlock_t cmd_lock;    /**< Lock protecting command list. */

link_t cmd_head;    /**< Command list. */

static cmd_info_t *parse_cmdline(char *cmdline, size_t len);

static int cmd_help(cmd_arg_t *cmd);

static cmd_info_t help_info;

/** Initialize kconsole data structures. */

void kconsole_init(void)

{

    spinlock_initialize(&cmd_lock);

    list_initialize(&cmd_head);

    help_info.name = "help";

    help_info.description = "List supported commands.";

    help_info.func = cmd_help;

    help_info.argc = 0;

    help_info.argv = NULL;

    spinlock_initialize(&help_info.lock);

    link_initialize(&help_info.link);

    if (!cmd_register(&help_info))

        panic("could not register command\n");

}

/** Register kconsole command.

 *

 * @param cmd Structure describing the command.

 *

 * @return 0 on failure, 1 on success.

 */

int cmd_register(cmd_info_t *cmd)

{

    ipl_t ipl;

    link_t *cur;

    ipl = interrupts_disable();

    spinlock_lock(&cmd_lock);

    /*

     * Make sure the command is not already listed.

     */

    for (cur = cmd_head.next; cur != &cmd_head; cur = cur->next) {

        cmd_info_t *hlp;

        hlp = list_get_instance(cur, cmd_info_t, link);

        if (hlp == cmd) {

            /* The command is already there. */

            spinlock_unlock(&cmd_lock);

            interrupts_restore(ipl);

            return 0;

        }

        /* Avoid deadlock. */

        if (hlp < cmd) {

            spinlock_lock(&hlp->lock);

            spinlock_lock(&cmd->lock);

        } else {

            spinlock_lock(&cmd->lock);

            spinlock_lock(&hlp->lock);

        }

        if ((strcmp(hlp->name, cmd->name, strlen(cmd->name)) == 0)) {

            /* The command is already there. */

            spinlock_unlock(&hlp->lock);

            spinlock_unlock(&cmd->lock);

            spinlock_unlock(&cmd_lock);

            interrupts_restore(ipl);

            return 0;

        }

        spinlock_unlock(&hlp->lock);

        spinlock_unlock(&cmd->lock);

    }

    /*

     * Now the command can be added.

     */

    list_append(&cmd->link, &cmd_head);

    spinlock_unlock(&cmd_lock);

    interrupts_restore(ipl);

    return 1;

}

    cmd_info_t *cmd_info;

    count_t len;

        cmdline[len] = '\0';

        cmd_info = parse_cmdline(cmdline, len);

        if (!cmd_info) {

            continue;

        }

        (void) cmd_info->func(cmd_info->argv);

/** Parse command line.

 *

 * @param cmdline Command line as read from input device.

 * @param len Command line length.

 *

 * @return Structure describing the command.

 */

cmd_info_t *parse_cmdline(char *cmdline, size_t len)

{

    index_t start = 0, end = 0;

    bool found_start = false;

    cmd_info_t *cmd = NULL;

    link_t *cur;

    ipl_t ipl;

    int i;

    for (i = 0; i < len; i++) {

        if (!found_start) {

            if (is_white(cmdline[i]))

                start++;

            else

                found_start = true;

        } else {

            if (is_white(cmdline[i]))

                break;

        }

    }

    end = i - 1;

    if (!found_start) {

        /* Command line did not contain alphanumeric word. */

        return NULL;

    }

    ipl = interrupts_disable();

    spinlock_lock(&cmd_lock);

    for (cur = cmd_head.next; cur != &cmd_head; cur = cur->next) {

        cmd_info_t *hlp;

        hlp = list_get_instance(cur, cmd_info_t, link);

        spinlock_lock(&hlp->lock);

        if (strcmp(hlp->name, &cmdline[start], (end - start) + 1) == 0) {

            cmd = hlp;

            break;

        }

        spinlock_unlock(&hlp->lock);

    }

    spinlock_unlock(&cmd_lock);

    if (!cmd) {

        /* Unknown command. */

        interrupts_restore(ipl);

        return NULL;

    }

    /* cmd == hlp is locked */

    /*

     * TODO:

     * The command line must be further analyzed and

     * the parameters therefrom must be matched and

     * converted to those specified in the cmd info

     * structure.

     */

    spinlock_unlock(&cmd->lock);

    interrupts_restore(ipl);

    return cmd;

}

/** List supported commands.

 *

 * @param cmd Argument vector.

 *

 * @return 0 on failure, 1 on success.

 */

int cmd_help(cmd_arg_t *cmd)

{

    link_t *cur;

    ipl_t ipl;

    ipl = interrupts_disable();

    spinlock_lock(&cmd_lock);

    for (cur = cmd_head.next; cur != &cmd_head; cur = cur->next) {

        cmd_info_t *hlp;

        hlp = list_get_instance(cur, cmd_info_t, link);

        spinlock_lock(&hlp->lock);

        printf("%s\t%s\n", hlp->name, hlp->description);

        spinlock_unlock(&hlp->lock);

    }

    spinlock_unlock(&cmd_lock);

    interrupts_restore(ipl);

    return 1;

}