/*
 * buffer.c
 *
 * Message buffer implementation for CProof.
 *
 * This module provides an in-memory buffer for managing active chat entries in the
 * console-based XMPP client. Separate from persistent SQLite storage, it holds
 * messages and metadata solely for UI rendering, ensuring responsive scrolling and
 * display without exceeding ncurses pad limits (10k lines). By tracking rendered
 * line counts per entry, it proactively trims content to prevent overflow, enabling
 * seamless integration with ncurses for position-aware rendering.
 *
 * Key features and operations:
 *   - Append/prepend entries (messages) with automatic line-based cleanup.
 *   - Track cumulative lines for overflow prevention and efficient buffer sizing.
 *   - Remove entries by ID or index; mark delivery receipts as received.
 *   - Retrieve entries by index or ID for rendering and history queries.
 *   - Store metadata including timestamps, senders, themes, and ncurses y-positions.
 *
 * CProof. Fork of Profanity (since 2025).
 *
 * Copyright (C) 2012 - 2019 James Booth <boothj5@gmail.com>
 * Copyright (C) 2019 - 2025 Michael Vetter <jubalh@iodoru.org>
 * Copyright (C) 2025 CProof Developers
 *
 * Licensed under the GNU General Public License, version 3,
 * with the OpenSSL exception. See LICENSE for details.
 *
 * vim: expandtab:ts=4:sts=4:sw=4
 */

#include "config.h"
#include "ui/window_list.h"

#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <stdlib.h>

#include <glib.h>
#ifdef HAVE_NCURSESW_NCURSES_H
#include <ncursesw/ncurses.h>
#elif HAVE_NCURSES_H
#include <ncurses.h>
#elif HAVE_CURSES_H
#include <curses.h>
#endif

#include "log.h"
#include "ui/window.h"
#include "ui/buffer.h"

#define STRDUP_OR_NULL(str) ((str) ? strdup(str) : NULL)

static void _free_entry(ProfBuffEntry* entry);
static ProfBuffEntry* _create_entry(const char* show_char, int pad_indent, GDateTime* time, int flags, theme_item_t theme_item, const char* const display_from, const char* const from_jid, const char* const message, DeliveryReceipt* receipt, const char* const id, int y_start_pos, int y_end_pos);
static void _buffer_add(ProfBuff buffer, const char* show_char, int pad_indent, GDateTime* time, int flags, theme_item_t theme_item, const char* const display_from, const char* const from_jid, const char* const message, DeliveryReceipt* receipt, const char* const id, int y_start_pos, int y_end_pos, gboolean append);

ProfBuff
buffer_create(void)
{
    ProfBuff new_buff = malloc(sizeof(struct prof_buff_t));
    new_buff->entries = NULL;
    new_buff->lines = 0;
    return new_buff;
}

int
buffer_size(ProfBuff buffer)
{
    return g_slist_length(buffer->entries);
}

void
buffer_free(ProfBuff buffer)
{
    g_slist_free_full(buffer->entries, (GDestroyNotify)_free_entry);
    free(buffer);
}

void
buffer_append(ProfBuff buffer, const char* show_char, int pad_indent, GDateTime* time, int flags, theme_item_t theme_item, const char* const display_from, const char* const from_jid, const char* const message, DeliveryReceipt* receipt, const char* const id, int y_start_pos, int y_end_pos)
{
    _buffer_add(buffer, show_char, pad_indent, time, flags, theme_item, display_from, from_jid, message, receipt, id, y_start_pos, y_end_pos, TRUE);
}

void
buffer_prepend(ProfBuff buffer, const char* show_char, int pad_indent, GDateTime* time, int flags, theme_item_t theme_item, const char* const display_from, const char* const from_jid, const char* const message, DeliveryReceipt* receipt, const char* const id, int y_start_pos, int y_end_pos)
{
    _buffer_add(buffer, show_char, pad_indent, time, flags, theme_item, display_from, from_jid, message, receipt, id, y_start_pos, y_end_pos, FALSE);
}

static void
_buffer_add(ProfBuff buffer, const char* show_char, int pad_indent, GDateTime* time, int flags, theme_item_t theme_item, const char* const display_from, const char* const from_jid, const char* const message, DeliveryReceipt* receipt, const char* const id, int y_start_pos, int y_end_pos, gboolean append)
{
    ProfBuffEntry* e = _create_entry(show_char, pad_indent, time, flags, theme_item, display_from, from_jid, message, receipt, id, y_start_pos, y_end_pos);

    buffer->lines += e->_lines;

    // With 10% margin to ensure overflow prevention
    while (buffer->lines >= 20 && g_slist_length(buffer->entries) > 1) {
        log_debug("DELETING");
        // Delete message from the opposite size to free buffer
        GSList* buffer_entry_to_delete = append ? buffer->entries : g_slist_last(buffer->entries);
        ProfBuffEntry* entry_to_delete = (ProfBuffEntry*)buffer_entry_to_delete->data;
        // log_debug("(Messages left in buffer: %d) DELETING: %s", g_slist_length(buffer->entries), entry_to_delete->id);
        buffer->lines -= entry_to_delete->_lines;
        _free_entry(entry_to_delete);
        buffer->entries = g_slist_delete_link(buffer->entries, buffer_entry_to_delete);
    }

    if (from_jid && y_end_pos == y_start_pos) {
        // win_redraw will redraw with entries above removed,
        // it will also recalculate actual size of the message that caused overflow
        int old_lines = buffer->lines;
        win_redraw(wins_get_current());
        log_debug("Ncurses Overflow! From: %s, position: %d, ID: %s, append: %s, used message buffer size: %d, rendered lines: (old: %d/ actual: %d/ max: %d)",
                  from_jid, y_start_pos, id, append ? "TRUE" : "FALSE", g_slist_length(buffer->entries), old_lines, buffer->lines, PAD_SIZE);
    }

    buffer->entries = append ? g_slist_append(buffer->entries, e) : g_slist_prepend(buffer->entries, e);
}

void
buffer_remove_entry_by_id(ProfBuff buffer, const char* const id)
{
    GSList* entries = buffer->entries;
    while (entries) {
        ProfBuffEntry* entry = entries->data;
        if (entry->id && (g_strcmp0(entry->id, id) == 0)) {
            buffer->lines -= entry->_lines;
            _free_entry(entry);
            buffer->entries = g_slist_delete_link(buffer->entries, entries);
            break;
        }
        entries = g_slist_next(entries);
    }
}

void
buffer_remove_entry(ProfBuff buffer, int entry)
{
    GSList* node = g_slist_nth(buffer->entries, entry);
    ProfBuffEntry* e = node->data;
    buffer->lines -= e->_lines;
    _free_entry(e);
    buffer->entries = g_slist_delete_link(buffer->entries, node);
}

gboolean
buffer_mark_received(ProfBuff buffer, const char* const id)
{
    GSList* entries = buffer->entries;
    while (entries) {
        ProfBuffEntry* entry = entries->data;
        if (entry->receipt && g_strcmp0(entry->id, id) == 0) {
            if (!entry->receipt->received) {
                entry->receipt->received = TRUE;
                return TRUE;
            }
        }
        entries = g_slist_next(entries);
    }

    return FALSE;
}

ProfBuffEntry*
buffer_get_entry(ProfBuff buffer, int entry)
{
    GSList* node = g_slist_nth(buffer->entries, entry);
    return node->data;
}

ProfBuffEntry*
buffer_get_entry_by_id(ProfBuff buffer, const char* const id)
{
    GSList* entries = buffer->entries;
    while (entries) {
        ProfBuffEntry* entry = entries->data;
        if (g_strcmp0(entry->id, id) == 0) {
            return entry;
        }
        entries = g_slist_next(entries);
    }

    return NULL;
}

static ProfBuffEntry*
_create_entry(const char* show_char, int pad_indent, GDateTime* time, int flags, theme_item_t theme_item, const char* const display_from, const char* const from_jid, const char* const message, DeliveryReceipt* receipt, const char* const id, int y_start_pos, int y_end_pos)
{
    ProfBuffEntry* e = malloc(sizeof(struct prof_buff_entry_t));
    e->show_char = STRDUP_OR_NULL(show_char);
    e->pad_indent = pad_indent;
    e->flags = flags;
    e->theme_item = theme_item;
    e->time = g_date_time_ref(time);
    e->display_from = STRDUP_OR_NULL(display_from);
    e->from_jid = STRDUP_OR_NULL(from_jid);
    e->message = STRDUP_OR_NULL(message);
    e->receipt = receipt;
    e->id = STRDUP_OR_NULL(id);
    e->y_start_pos = y_start_pos;
    e->y_end_pos = y_end_pos;
    e->_lines = e->y_end_pos - e->y_start_pos;

    return e;
}

static void
_free_entry(ProfBuffEntry* entry)
{
    free(entry->id);
    free(entry->message);
    free(entry->from_jid);
    free(entry->display_from);
    g_date_time_unref(entry->time);
    free(entry->show_char);
    free(entry->receipt);
    free(entry);
}