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/*
 * Copyright (c) 2005 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup genericconsole
 * @{
 */

/**
 * @file  kconsole.c
 * @brief Kernel console.
 *
 * This file contains kernel thread managing the kernel console.
 *
 */

#include <console/kconsole.h>
#include <console/console.h>
#include <console/chardev.h>
#include <console/cmd.h>
#include <print.h>
#include <panic.h>
#include <arch/types.h>
#include <adt/list.h>
#include <arch.h>
#include <macros.h>
#include <debug.h>
#include <func.h>
#include <string.h>
#include <macros.h>
#include <sysinfo/sysinfo.h>
#include <ddi/device.h>
#include <symtab.h>
#include <errno.h>
#include <putchar.h>
#include <string.h>

/** Simple kernel console.
 *
 * The console is realized by kernel thread kconsole.
 * It doesn't understand any useful command 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_INITIALIZE(cmd_lock);  /**< Lock protecting command list. */
LIST_INITIALIZE(cmd_head);      /**< Command list. */

static wchar_t history[KCONSOLE_HISTORY][MAX_CMDLINE] = {};
static size_t history_pos = 0;

/** Initialize kconsole data structures
 *
 * This is the most basic initialization, almost no
 * other kernel subsystem is ready yet.
 *
 */
void kconsole_init(void)
{
    unsigned int i;
    
    cmd_init();
    for (i = 0; i < KCONSOLE_HISTORY; i++)
        history[i][0] = 0;
}

/** Register kconsole command.
 *
 * @param cmd Structure describing the command.
 *
 * @return False on failure, true on success.
 *
 */
bool cmd_register(cmd_info_t *cmd)
{
    link_t *cur;
    
    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 = list_get_instance(cur, cmd_info_t, link);
        
        if (hlp == cmd) {
            /* The command is already there. */
            spinlock_unlock(&cmd_lock);
            return false;
        }
        
        /* Avoid deadlock. */
        if (hlp < cmd) {
            spinlock_lock(&hlp->lock);
            spinlock_lock(&cmd->lock);
        } else {
            spinlock_lock(&cmd->lock);
            spinlock_lock(&hlp->lock);
        }
        
        if (str_cmp(hlp->name, cmd->name) == 0) {
            /* The command is already there. */
            spinlock_unlock(&hlp->lock);
            spinlock_unlock(&cmd->lock);
            spinlock_unlock(&cmd_lock);
            return false;
        }
        
        spinlock_unlock(&hlp->lock);
        spinlock_unlock(&cmd->lock);
    }
    
    /*
     * Now the command can be added.
     */
    list_append(&cmd->link, &cmd_head);
    
    spinlock_unlock(&cmd_lock);
    return true;
}

/** Print count times a character */
static void print_cc(wchar_t ch, size_t count)
{
    size_t i;
    for (i = 0; i < count; i++)
        putchar(ch);
}

/** Try to find a command beginning with prefix */
static const char *cmdtab_search_one(const char *name, link_t **startpos)
{
    size_t namelen = str_length(name);
    
    spinlock_lock(&cmd_lock);
    
    if (*startpos == NULL)
        *startpos = cmd_head.next;
    
    for (; *startpos != &cmd_head; *startpos = (*startpos)->next) {
        cmd_info_t *hlp = list_get_instance(*startpos, cmd_info_t, link);
        
        const char *curname = hlp->name;
        if (str_length(curname) < namelen)
            continue;
        
        if (str_lcmp(curname, name, namelen) == 0) {
            spinlock_unlock(&cmd_lock);
            return (curname + str_lsize(curname, namelen));
        }
    }
    
    spinlock_unlock(&cmd_lock);
    return NULL;
}

/** Command completion of the commands
 *
 * @param name String to match, changed to hint on exit
 * @param size Input buffer size
 *
 * @return Number of found matches
 *
 */
static int cmdtab_compl(char *input, size_t size)
{
    const char *name = input;
    
    size_t found = 0;
    link_t *pos = NULL;
    const char *hint;
    char output[MAX_CMDLINE];
    
    output[0] = 0;
    
    while ((hint = cmdtab_search_one(name, &pos))) {
        if ((found == 0) || (str_length(output) > str_length(hint)))
            str_cpy(output, MAX_CMDLINE, hint);
        
        pos = pos->next;
        found++;
    }
    
    if ((found > 1) && (str_length(output) != 0)) {
        printf("\n");
        pos = NULL;
        while ((hint = cmdtab_search_one(name, &pos))) {
            cmd_info_t *hlp = list_get_instance(pos, cmd_info_t, link);
            printf("%s (%s)\n", hlp->name, hlp->description);
            pos = pos->next;
        }
    }
    
    if (found > 0)
        str_cpy(input, size, output);
    
    return found;
}

static wchar_t *clever_readline(const char *prompt, indev_t *indev)
{
    printf("%s> ", prompt);
    
    size_t position = 0;
    wchar_t *current = history[history_pos];
    current[0] = 0;
    
    while (true) {
        wchar_t ch = indev_pop_character(indev);
        
        if (ch == '\n') {
            /* Enter */
            putchar(ch);
            break;
        }
        
        if (ch == '\b') {
            /* Backspace */
            if (position == 0)
                continue;
            
            if (wstr_remove(current, position - 1)) {
                position--;
                putchar('\b');
                printf("%ls ", current + position);
                print_cc('\b', wstr_length(current) - position + 1);
                continue;
            }
        }
        
        if (ch == '\t') {
            /* Tab completion */
            
            /* Move to the end of the word */
            for (; (current[position] != 0) && (!isspace(current[position]));
                position++)
                putchar(current[position]);
            
            if (position == 0)
                continue;
            
            /* Find the beginning of the word
               and copy it to tmp */
            size_t beg;
            for (beg = position - 1; (beg > 0) && (!isspace(current[beg]));
                beg--);
            
            if (isspace(current[beg]))
                beg++;
            
            char tmp[STR_BOUNDS(MAX_CMDLINE)];
            wstr_nstr(tmp, current + beg, position - beg + 1);
            
            int found;
            if (beg == 0) {
                /* Command completion */
                found = cmdtab_compl(tmp, STR_BOUNDS(MAX_CMDLINE));
            } else {
                /* Symbol completion */
                found = symtab_compl(tmp, STR_BOUNDS(MAX_CMDLINE));
            }
            
            if (found == 0)
                continue;
            
            if (found > 1) {
                /* No unique hint, list was printed */
                printf("%s> ", prompt);
                printf("%ls", current);
                print_cc('\b', wstr_length(current) - position);
                continue;
            }
            
            /* We have a hint */
            
            size_t off = 0;
            size_t i = 0;
            while ((ch = str_decode(tmp, &off, STR_NO_LIMIT)) != 0) {
                if (!wstr_linsert(current, ch, position + i, MAX_CMDLINE))
                    break;
                i++;
            }
            
            printf("%ls", current + position);
            position += str_length(tmp);
            print_cc('\b', wstr_length(current) - position);
            
            if (position == wstr_length(current)) {
                /* Insert a space after the last completed argument */
                if (wstr_linsert(current, ' ', position, MAX_CMDLINE)) {
                    printf("%ls", current + position);
                    position++;
                }
            }
            continue;
        }
        
        if (ch == U_LEFT_ARROW) {
            /* Left */
            if (position > 0) {
                putchar('\b');
                position--;
            }
            continue;
        }
        
        if (ch == U_RIGHT_ARROW) {
            /* Right */
            if (position < wstr_length(current)) {
                putchar(current[position]);
                position++;
            }
            continue;
        }
        
        if ((ch == U_UP_ARROW) || (ch == U_DOWN_ARROW)) {
            /* Up, down */
            print_cc('\b', position);
            print_cc(' ', wstr_length(current));
            print_cc('\b', wstr_length(current));
            
            if (ch == U_UP_ARROW) {
                /* Up */
                if (history_pos == 0)
                    history_pos = KCONSOLE_HISTORY - 1;
                else
                    history_pos--;
            } else {
                /* Down */
                history_pos++;
                history_pos = history_pos % KCONSOLE_HISTORY;
            }
            current = history[history_pos];
            printf("%ls", current);
            position = wstr_length(current);
            continue;
        }
        
        if (ch == U_HOME_ARROW) {
            /* Home */
            print_cc('\b', position);
            position = 0;
            continue;
        }
        
        if (ch == U_END_ARROW) {
            /* End */
            printf("%ls", current + position);
            position = wstr_length(current);
            continue;
        }
        
        if (ch == U_DELETE) {
            /* Delete */
            if (position == wstr_length(current))
                continue;
            
            if (wstr_remove(current, position)) {
                printf("%ls ", current + position);
                print_cc('\b', wstr_length(current) - position + 1);
            }
            continue;
        }
        
        if (wstr_linsert(current, ch, position, MAX_CMDLINE)) {
            printf("%ls", current + position);
            position++;
            print_cc('\b', wstr_length(current) - position);
        }
    }
    
    if (wstr_length(current) > 0) {
        history_pos++;
        history_pos = history_pos % KCONSOLE_HISTORY;
    }
    
    return current;
}

bool kconsole_check_poll(void)
{
    return check_poll(stdin);
}

static bool parse_int_arg(const char *text, size_t len, unative_t *result)
{
    bool isaddr = false;
    bool isptr = false;
    
    /* If we get a name, try to find it in symbol table */
    if (text[0] == '&') {
        isaddr = true;
        text++;
        len--;
    } else if (text[0] == '*') {
        isptr = true;
        text++;
        len--;
    }
    
    if ((text[0] < '0') || (text[0] > '9')) {
        char symname[MAX_SYMBOL_NAME];
        str_ncpy(symname, MAX_SYMBOL_NAME, text, len + 1);
        
        uintptr_t symaddr;
        int rc = symtab_addr_lookup(symname, &symaddr);
        switch (rc) {
        case ENOENT:
            printf("Symbol %s not found.\n", symname);
            return false;
        case EOVERFLOW:
            printf("Duplicate symbol %s.\n", symname);
            symtab_print_search(symname);
            return false;
        case ENOTSUP:
            printf("No symbol information available.\n");
            return false;
        }
        
        if (isaddr)
            *result = (unative_t) symaddr;
        else if (isptr)
            *result = **((unative_t **) symaddr);
        else
            *result = *((unative_t *) symaddr);
    } else {
        /* It's a number - convert it */
        *result = atoi(text);
        if (isptr)
            *result = *((unative_t *) *result);
    }
    
    return true;
}

/** Parse argument.
 *
 * Find start and end positions of command line argument.
 *
 * @param cmdline Command line as read from the input device.
 * @param size    Size (in bytes) of the string.
 * @param start   On entry, 'start' contains pointer to the offset
 *                of the first unprocessed character of cmdline.
 *                On successful exit, it marks beginning of the next argument.
 * @param end     Undefined on entry. On exit, 'end' is the offset of the first
 *                character behind the next argument.
 *
 * @return False on failure, true on success.
 *
 */
static bool parse_argument(const char *cmdline, size_t size, size_t *start, size_t *end)
{
    ASSERT(start != NULL);
    ASSERT(end != NULL);
    
    bool found_start = false;
    size_t offset = *start;
    size_t prev = *start;
    wchar_t ch;
    
    while ((ch = str_decode(cmdline, &offset, size)) != 0) {
        if (!found_start) {
            if (!isspace(ch)) {
                *start = prev;
                found_start = true;
            }
        } else {
            if (isspace(ch))
                break;
        }
        
        prev = offset;
    }
    *end = prev;
    
    return found_start;
}

/** Parse command line.
 *
 * @param cmdline Command line as read from input device. 
 * @param size    Size (in bytes) of the string.
 *
 * @return Structure describing the command.
 *
 */
static cmd_info_t *parse_cmdline(const char *cmdline, size_t size)
{
    size_t start = 0;
    size_t end = 0;
    if (!parse_argument(cmdline, size, &start, &end)) {
        /* Command line did not contain alphanumeric word. */
        return NULL;
    }
    spinlock_lock(&cmd_lock);
    
    cmd_info_t *cmd = NULL;
    link_t *cur;
    
    for (cur = cmd_head.next; cur != &cmd_head; cur = cur->next) {
        cmd_info_t *hlp = list_get_instance(cur, cmd_info_t, link);
        spinlock_lock(&hlp->lock);
        
        if (str_lcmp(hlp->name, cmdline + start,
            max(str_length(hlp->name),
            str_nlength(cmdline + start, (size_t) (end - start) - 1))) == 0) {
            cmd = hlp;
            break;
        }
        
        spinlock_unlock(&hlp->lock);
    }
    
    spinlock_unlock(&cmd_lock);
    
    if (!cmd) {
        /* Unknown command. */
        printf("Unknown command.\n");
        return NULL;
    }
    
    /* cmd == hlp is locked */
    
    /*
     * The command line must be further analyzed and
     * the parameters therefrom must be matched and
     * converted to those specified in the cmd info
     * structure.
     */
    
    bool error = false;
    size_t i;
    for (i = 0; i < cmd->argc; i++) {
        start = end;
        if (!parse_argument(cmdline, size, &start, &end)) {
            printf("Too few arguments.\n");
            spinlock_unlock(&cmd->lock);
            return NULL;
        }
        
        char *buf;
        switch (cmd->argv[i].type) {
        case ARG_TYPE_STRING:
            buf = (char *) cmd->argv[i].buffer;
            str_ncpy(buf, cmd->argv[i].len, cmdline + start,
                end - start);
            break;
        case ARG_TYPE_INT:
            if (!parse_int_arg(cmdline + start, end - start,
                &cmd->argv[i].intval))
                error = true;
            break;
        case ARG_TYPE_VAR:
            if ((start < end - 1) && (cmdline[start] == '"')) {
                if (cmdline[end - 1] == '"') {
                    buf = (char *) cmd->argv[i].buffer;
                    str_ncpy(buf, cmd->argv[i].len,
                        cmdline + start + 1,
                        (end - start) - 1);
                    cmd->argv[i].intval = (unative_t) buf;
                    cmd->argv[i].vartype = ARG_TYPE_STRING;
                } else {
                    printf("Wrong synxtax.\n");
                    error = true;
                }
            } else if (parse_int_arg(cmdline + start,
                end - start, &cmd->argv[i].intval)) {
                cmd->argv[i].vartype = ARG_TYPE_INT;
            } else {
                printf("Unrecognized variable argument.\n");
                error = true;
            }
            break;
        case ARG_TYPE_INVALID:
        default:
            printf("Invalid argument type\n");
            error = true;
            break;
        }
    }
    
    if (error) {
        spinlock_unlock(&cmd->lock);
        return NULL;
    }
    
    start = end;
    if (parse_argument(cmdline, size, &start, &end)) {
        printf("Too many arguments.\n");
        spinlock_unlock(&cmd->lock);
        return NULL;
    }
    
    spinlock_unlock(&cmd->lock);
    return cmd;
}

/** Kernel console prompt.
 *
 * @param prompt Kernel console prompt (e.g kconsole/panic).
 * @param msg    Message to display in the beginning.
 * @param kcon   Wait for keypress to show the prompt
 *               and never exit.
 *
 */
void kconsole(char *prompt, char *msg, bool kcon)
{
    if (!stdin) {
        LOG("No stdin for kernel console");
        return;
    }
    
    if (msg)
        printf("%s", msg);
    
    if (kcon)
        indev_pop_character(stdin);
    else
        printf("Type \"exit\" to leave the console.\n");
    
    while (true) {
        wchar_t *tmp = clever_readline((char *) prompt, stdin);
        size_t len = wstr_length(tmp);
        if (!len)
            continue;
        
        char cmdline[STR_BOUNDS(MAX_CMDLINE)];
        wstr_nstr(cmdline, tmp, STR_BOUNDS(MAX_CMDLINE));
        
        if ((!kcon) && (len == 4) && (str_lcmp(cmdline, "exit", 4) == 0))
            break;
        
        cmd_info_t *cmd_info = parse_cmdline(cmdline, STR_BOUNDS(MAX_CMDLINE));
        if (!cmd_info)
            continue;
        
        (void) cmd_info->func(cmd_info->argv);
    }
}

/** Kernel console managing thread.
 *
 */
void kconsole_thread(void *data)
{
    kconsole("kconsole", "Kernel console ready (press any key to activate)\n", true);
}

/** @}
 */