/**
 * @file split_screen.c
 * @brief Split screen implementation
 */

#include "../include/split_screen.h"
#include "../include/buffer.h"
#include "../include/editor_op.h"
#include <stdlib.h>
#include <string.h>

#include "include/utils.h"

extern struct editorConfig E;

/**
 * @brief Initializes split screen system with single fullscreen pane
 */
void splitScreenInit(void) {
    E.layout.mode = SPLIT_NONE;
    E.layout.num_panes = 1;
    E.layout.active_pane = 0;

    E.layout.panes = bAlloc(sizeof(EditorPane) * 2);

    // Initialize single fullscreen pane
    E.layout.panes[0].buffer_id = -1; // No buffer for now
    E.layout.panes[0].origin_y = 0;
    E.layout.panes[0].origin_x = 0;
    E.layout.panes[0].height = E.screenrows - 2;  // Leave room for status bar
    E.layout.panes[0].width = E.screencols;
    E.layout.panes[0].cursor_x = 0;
    E.layout.panes[0].cursor_y = 0;
    E.layout.panes[0].y_offset = 0;
    E.layout.panes[0].x_offset = 0;
    E.layout.panes[0].is_active = 1;
}

/**
 * @brief Splits screen vertically (left-right)
 * @param buffer_id_left Buffer ID for left pane
 * @param buffer_id_right Buffer ID for right pane
 * @return 0 on success, -1 on failure
 */
int splitScreenVertical(int buffer_id_left, int buffer_id_right) {
    // Verify both buffers exist
    if (bufferFindById(buffer_id_left) == NULL ||
        bufferFindById(buffer_id_right) == NULL) {
        editorSetStatusMessage("Error: invalid buffer IDs");
        return -1;
    }

    // bReallocate panes array
    E.layout.panes = bRealloc(E.layout.panes, sizeof(EditorPane) * 2);
    E.layout.mode = SPLIT_VERTICAL;
    E.layout.num_panes = 2;
    E.layout.active_pane = 0;

    int half_width = E.screencols / 2;
    int pane_height = E.screenrows;  // Leave room for status bar

    // Left pane
    E.layout.panes[0].buffer_id = buffer_id_left;
    E.layout.panes[0].origin_y = 0;
    E.layout.panes[0].origin_x = 0;
    E.layout.panes[0].height = pane_height;
    E.layout.panes[0].width = half_width;
    E.layout.panes[0].cursor_x = 0;
    E.layout.panes[0].cursor_y = 0;
    E.layout.panes[0].y_offset = 0;
    E.layout.panes[0].x_offset = 0;
    E.layout.panes[0].is_active = 1;

    // Right pane
    E.layout.panes[1].buffer_id = buffer_id_right;
    E.layout.panes[1].origin_y = 0;
    E.layout.panes[1].origin_x = half_width;
    E.layout.panes[1].height = pane_height;
    E.layout.panes[1].width = E.screencols - half_width;
    E.layout.panes[1].cursor_x = 0;
    E.layout.panes[1].cursor_y = 0;
    E.layout.panes[1].y_offset = 0;
    E.layout.panes[1].x_offset = 0;
    E.layout.panes[1].is_active = 0;

    editorSetStatusMessage("Vertical split: %d | %d", buffer_id_left, buffer_id_right);
    return 0;
}

/**
 * @brief Splits screen horizontally (top-bottom)
 * @param buffer_id_top Buffer ID for top pane
 * @param buffer_id_bottom Buffer ID for bottom pane
 * @return 0 on success, -1 on failure
 */
int splitScreenHorizontal(int buffer_id_top, int buffer_id_bottom) {
    // Verify both buffers exist
    if (bufferFindById(buffer_id_top) == NULL ||
        bufferFindById(buffer_id_bottom) == NULL) {
        editorSetStatusMessage("Error: invalid buffer IDs");
        return -1;
    }

    // bReallocate panes array
    E.layout.panes = bRealloc(E.layout.panes, sizeof(EditorPane) * 2);
    E.layout.mode = SPLIT_HORIZONTAL;
    E.layout.num_panes = 2;
    E.layout.active_pane = 0;

    int half_height = (E.screenrows - 2) / 2;  // Account for status bar

    // Top pane
    E.layout.panes[0].buffer_id = buffer_id_top;
    E.layout.panes[0].origin_y = 0;
    E.layout.panes[0].origin_x = 0;
    E.layout.panes[0].height = half_height;
    E.layout.panes[0].width = E.screencols;
    E.layout.panes[0].cursor_x = 0;
    E.layout.panes[0].cursor_y = 0;
    E.layout.panes[0].y_offset = 0;
    E.layout.panes[0].x_offset = 0;
    E.layout.panes[0].is_active = 1;

    // Bottom pane
    E.layout.panes[1].buffer_id = buffer_id_bottom;
    E.layout.panes[1].origin_y = half_height;
    E.layout.panes[1].origin_x = 0;
    E.layout.panes[1].height = E.screenrows - 2 - half_height;
    E.layout.panes[1].width = E.screencols;
    E.layout.panes[1].cursor_x = 0;
    E.layout.panes[1].cursor_y = 0;
    E.layout.panes[1].x_offset = 0;
    E.layout.panes[1].y_offset = 0;
    E.layout.panes[1].is_active = 0;

    editorSetStatusMessage("Horizontal split: %d / %d", buffer_id_top, buffer_id_bottom);
    return 0;
}

/**
 * @brief Returns to single buffer fullscreen
 */
void splitScreenUnify(void) {
    E.layout.mode = SPLIT_NONE;
    E.layout.num_panes = 1;
    E.layout.active_pane = 0;

    E.layout.panes[0].origin_x = 0;
    E.layout.panes[0].origin_y = 0;
    E.layout.panes[0].height = E.screenrows;
    E.layout.panes[0].width = E.screencols;
    E.layout.panes[0].is_active = 1;

    editorSetStatusMessage("Unified view");
}

/**
 * @brief Switches active pane (focus moves between splits)
 * @return 0 on success, -1 on failure
 */
int splitScreenSwitchPane(void) {
    if (E.layout.num_panes < 2) {
        editorSetStatusMessage("No split to switch");
        return -1;
    }

    // Deactivate current pane
    E.layout.panes[E.layout.active_pane].is_active = 0;

    // Move to next pane
    E.layout.active_pane = (E.layout.active_pane + 1) % E.layout.num_panes;

    // Activate new pane
    E.layout.panes[E.layout.active_pane].is_active = 1;

    editorSetStatusMessage("Switched to pane %d (buffer %d)",
                          E.layout.active_pane,
                          E.layout.panes[E.layout.active_pane].buffer_id);
    return 0;
}

/**
 * @brief Updates the active pane's buffer
 * @param buffer_id New buffer ID for active pane
 * @return 0 on success, -1 on failure
 */
int splitScreenSetPaneBuffer(int buffer_id) {
    if (bufferFindById(buffer_id) == NULL) {
        editorSetStatusMessage("Error: invalid buffer ID");
        return -1;
    }

    EditorPane *active = &E.layout.panes[E.layout.active_pane];
    active->buffer_id = buffer_id;
    active->cursor_x = 0;
    active->cursor_y = 0;
    active->origin_x = 0;
    active->origin_y = 0;

    editorSetStatusMessage("Pane %d now showing buffer %d",
                          E.layout.active_pane, buffer_id);
    return 0;
}

/**
 * @brief Gets current screen layout
 * @return Pointer to current ScreenLayout
 */
ScreenLayout *splitScreenGetLayout(void) {
    return &E.layout;
}

/**
 * @brief Gets active pane
 * @return Pointer to active EditorPane
 */
EditorPane *splitScreenGetActivePane(void) {
    if (E.layout.num_panes == 0) return NULL;
    return &E.layout.panes[E.layout.active_pane];
}