// Desktop Environment & Compositor for SUB-OS
#include <gui/gui_desktop.h>
#include <gui/gui_gfx.h>
#include <gui/gui_cursor.h>
#include <gui/gui_wm.h>
#include <gui/gui_apps.h>
#include <gui/gui_theme.h>
#include <drivers/fb.h>
#include <drivers/mouse.h>
#include <drivers/keyboard.h>
#include <drivers/rtc.h>
#include <drivers/cpufreq.h>
#include <lib/string.h>
#include <lib/printf.h>
#include <kernel/printk.h>

static bool g_start_menu_open = false;
static bool g_desktop_running = false;
static bool g_prev_left = false;

void gui_desktop_init(void) {
    const fb_info_t* fb = fb_get_info();
    uint32_t* fb_addr = fb ? fb->address : NULL;
    int w = fb ? fb->width : 320;
    int h = fb ? fb->height : 200;

    gui_gfx_init(fb_addr, w, h);
    gui_cursor_init();
    gui_wm_init();
    mouse_set_bounds(w, h);
    g_start_menu_open = false;
}

void gui_desktop_render_background(void) {
    int sw = gui_gfx_get_width();
    int sh = gui_gfx_get_height();

    // Dark Cyberpunk / Navy Vertical Gradient Wallpaper
    gui_gfx_draw_gradient_v(0, 0, sw, sh - GUI_TASKBAR_HEIGHT, 0xFF0B132B, 0xFF1C2541);

    // Subtle Grid Pattern
    for (int y = 0; y < sh - GUI_TASKBAR_HEIGHT; y += 20) {
        gui_gfx_draw_line(0, y, sw - 1, y, 0xFF141F36);
    }
    for (int x = 0; x < sw; x += 20) {
        gui_gfx_draw_line(x, 0, x, sh - GUI_TASKBAR_HEIGHT - 1, 0xFF141F36);
    }

    // Centered Desktop Brand Text Watermark
    gui_gfx_draw_string_shadow(sw / 2 - 40, sh / 2 - 20, "SUB-OS DESKTOP", 0xFF3A506B, 0xFF050811);
    gui_gfx_draw_string(sw / 2 - 28, sh / 2 - 8, "v0.2.0-LTS", 0xFF2A3C54);
}

void gui_desktop_render_taskbar(void) {
    int sw = gui_gfx_get_width();
    int sh = gui_gfx_get_height();
    int ty = sh - GUI_TASKBAR_HEIGHT;

    // Taskbar Bar Surface
    gui_gfx_fill_rect(0, ty, sw, GUI_TASKBAR_HEIGHT, GUI_THEME_TASKBAR_BG);
    gui_gfx_draw_line(0, ty, sw - 1, ty, GUI_THEME_BORDER);

    // Start Button
    uint32_t start_bg = g_start_menu_open ? GUI_THEME_PRIMARY_DARK : GUI_THEME_PRIMARY;
    gui_gfx_fill_rect(2, ty + 2, 54, 16, start_bg);
    gui_gfx_draw_rect(2, ty + 2, 54, 16, GUI_THEME_PRIMARY_DARK);
    gui_gfx_draw_string(6, ty + 6, "# SUB-OS", GUI_COLOR_WHITE);

    // Window Tabs in Taskbar
    int tab_x = 60;
    int win_count = gui_wm_get_window_count();
    for (int i = 0; i < win_count && tab_x < sw - 80; i++) {
        gui_window_t* win = gui_wm_get_window(i + 1);
        if (!win || !win->visible) continue;

        uint32_t tab_bg = win->active ? GUI_THEME_BG_ELEVATED : GUI_THEME_BG_SURFACE;
        gui_gfx_fill_rect(tab_x, ty + 2, 50, 16, tab_bg);
        gui_gfx_draw_rect(tab_x, ty + 2, 50, 16, win->active ? GUI_THEME_PRIMARY : GUI_THEME_BORDER);

        char short_title[6];
        strncpy(short_title, win->title, 5);
        short_title[5] = '\0';
        gui_gfx_draw_string(tab_x + 4, ty + 6, short_title, win->active ? GUI_THEME_TEXT_MAIN : GUI_THEME_TEXT_MUTED);

        tab_x += 54;
    }

    // System Tray (Clock & Telemetry)
    rtc_time_t time;
    rtc_get_time(&time);
    char time_str[10];
    snprintf(time_str, sizeof(time_str), "%02u:%02u:%02u", time.hour, time.minute, time.second);
    gui_gfx_draw_string_bg(sw - 50, ty + 6, time_str, GUI_THEME_PRIMARY, GUI_THEME_TASKBAR_BG);

    gui_gfx_fill_rect(sw - 68, ty + 5, 12, 10, GUI_THEME_SUCCESS);
    gui_gfx_draw_string(sw - 66, ty + 6, "24M", GUI_COLOR_WHITE);
}

void gui_desktop_render_start_menu(void) {
    if (!g_start_menu_open) return;

    int sh = gui_gfx_get_height();
    int menu_w = 95;
    int menu_h = 100;
    int mx = 2;
    int my = sh - GUI_TASKBAR_HEIGHT - menu_h - 2;

    gui_gfx_draw_shadow(mx, my, menu_w, menu_h, 3);
    gui_gfx_fill_rect(mx, my, menu_w, menu_h, GUI_THEME_BG_SURFACE);
    gui_gfx_draw_rect(mx, my, menu_w, menu_h, GUI_THEME_PRIMARY);

    const char* items[] = {
        ">_ Terminal",
        "[#] System Monitor",
        "[F] File Explorer",
        "[=] Calculator",
        "[*] Paint Studio",
        "[i] About SUB-OS",
        "[X] Exit GUI"
    };

    for (int i = 0; i < 7; i++) {
        int iy = my + 4 + i * 13;
        uint32_t fg = (i == 6) ? GUI_THEME_DANGER : GUI_THEME_TEXT_MAIN;
        gui_gfx_draw_string(mx + 6, iy, items[i], fg);
    }
}

void gui_desktop_toggle_start_menu(void) {
    g_start_menu_open = !g_start_menu_open;
}

bool gui_desktop_is_start_menu_open(void) {
    return g_start_menu_open;
}

void gui_desktop_handle_taskbar_click(int mx, int my) {
    int sw = gui_gfx_get_width();
    int sh = gui_gfx_get_height();
    int ty = sh - GUI_TASKBAR_HEIGHT;

    // Check Start Button
    if (mx >= 2 && mx <= 56 && my >= ty + 2 && my <= ty + 18) {
        gui_desktop_toggle_start_menu();
        return;
    }

    // Check Start Menu Click if open
    if (g_start_menu_open) {
        int menu_w = 95;
        int menu_h = 100;
        int smx = 2;
        int smy = sh - GUI_TASKBAR_HEIGHT - menu_h - 2;

        if (mx >= smx && mx <= smx + menu_w && my >= smy && my <= smy + menu_h) {
            int item_idx = (my - (smy + 4)) / 13;
            g_start_menu_open = false;
            switch (item_idx) {
                case 0: gui_app_terminal_launch(20, 20, 160, 100); break;
                case 1: gui_app_sysmon_launch(140, 20, 150, 115); break;
                case 2: gui_app_fileman_launch(40, 40, 140, 95); break;
                case 3: gui_app_calc_launch(60, 30, 110, 85); break;
                case 4: gui_app_paint_launch(80, 20, 130, 90); break;
                case 5: gui_app_about_launch(90, 50, 150, 75); break;
                case 6: g_desktop_running = false; break; // Exit GUI
                default: break;
            }
            return;
        } else {
            g_start_menu_open = false;
        }
    }

    // Check Window Tabs
    int tab_x = 60;
    int win_count = gui_wm_get_window_count();
    for (int i = 0; i < win_count && tab_x < sw - 80; i++) {
        if (mx >= tab_x && mx <= tab_x + 50 && my >= ty + 2 && my <= ty + 18) {
            gui_wm_focus_window(i + 1);
            return;
        }
        tab_x += 54;
    }
}

int gui_desktop_run(void) {
    gui_desktop_init();

    // Open initial standard desktop windows
    gui_app_sysmon_launch(150, 10, 150, 115);
    gui_app_terminal_launch(10, 15, 130, 95);

    g_desktop_running = true;
    printk(KERN_INFO "GUI: Desktop Environment session started (Press ESC to return to TTY)\n");

    int frame_limit = 0;
    while (g_desktop_running) {
        // 1. Process Mouse Input
        const mouse_state_t* ms = mouse_get_state();
        int mx = ms ? ms->x : 160;
        int my = ms ? ms->y : 100;
        bool left = ms ? ms->left_btn : false;
        bool right = ms ? ms->right_btn : false;

        gui_cursor_set_pos(mx, my);

        if (left && !g_prev_left) {
            int sh = gui_gfx_get_height();
            if (my >= sh - GUI_TASKBAR_HEIGHT || g_start_menu_open) {
                gui_desktop_handle_taskbar_click(mx, my);
            } else {
                gui_wm_handle_mouse(mx, my, left, right);
            }
        } else {
            gui_wm_handle_mouse(mx, my, left, right);
        }
        g_prev_left = left;

        // 2. Process Keyboard Input
        uint16_t key = keyboard_get_key();
        if (key != 0) {
            char c = (char)(key & 0xFF);
            if (c == 27) { // Escape key
                g_desktop_running = false;
                break;
            }
            gui_wm_handle_key(key);
        }

        // 3. Render Complete Desktop Scene
        gui_desktop_render_background();
        gui_wm_render();
        gui_desktop_render_taskbar();
        gui_desktop_render_start_menu();
        gui_cursor_draw();

        // 4. Present Framebuffer to Display
        gui_gfx_present();
    }

    printk(KERN_INFO "GUI: Desktop session ended, restored TTY console\n");
    return 0;
}