;; ===========================
;; Package Management Setup
;; ===========================
(require 'package)

;; Add MELPA, Org, and GNU package archives
(setq package-archives '(("melpa" . "https://melpa.org/packages/")
                         ("org" . "https://orgmode.org/elpa/")
                         ("gnu" . "https://elpa.gnu.org/packages/")))

(package-initialize)

;; Refresh package list if it's not already available
(unless package-archive-contents
  (package-refresh-contents))

;; Install use-package if it's not already installed
(unless (package-installed-p 'use-package)
  (package-install 'use-package))

(require 'use-package)
(setq use-package-always-ensure t) ;; Always ensure packages are installed

;; ===========================
;; Theme Configuration
;; ===========================

;; Define your preferred light and dark themes
(setq dark-theme 'zenburn)
(setq light-theme 'solarized-light)

;; Install Themes
(use-package solarized-theme
  :ensure t)

(use-package zenburn-theme
  :ensure t)

(defun my/get-system-appearance ()
  (cond
   ;; ---------------------------
   ;; macOS
   ;; ---------------------------
   ((eq system-type 'darwin)
    (if (string= (shell-command-to-string "defaults read -g AppleInterfaceStyle 2>/dev/null") "Dark\n")
        'dark
      'light))

   ;; ---------------------------
   ;; Windows
   ;; ---------------------------
   ((eq system-type 'windows-nt)
    ;; NOTE: For Windows 10/11, “AppsUseLightTheme” is under:
    ;; HKCU\Software\Microsoft\Windows\CurrentVersion\Themes\Personalize
    ;; Value of 1 => Light, 0 => Dark
    (let ((output (shell-command-to-string
                   "reg query \"HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize\" /v AppsUseLightTheme 2>nul")))
      (cond
       ((string-match "0x1" output) 'light)
       ((string-match "0x0" output) 'dark)
       (t nil))))

   ;; ---------------------------
   ;; GNOME-based Linux
   ;; ---------------------------
   ((eq system-type 'gnu/linux)
    ;; If you're on GNOME 42+, `color-scheme` often shows 'prefer-dark' or 'prefer-light'.
    ;; If the user is using an older system or a different DE, this may fail or return an empty string.
    (let ((gsettings-output (string-trim
                             (shell-command-to-string
                              "gsettings get org.gnome.desktop.interface color-scheme 2>/dev/null"))))
      (cond
       ((string-match "dark" gsettings-output) 'dark)
       ((string-match "light" gsettings-output) 'light)
       (t nil))))

   ;; ---------------------------
   ;; Otherwise, undetermined
   ;; ---------------------------

   (t nil)))

(defun my/set-theme-based-on-appearance ()
  "Set Emacs theme based on system appearance if possible, otherwise fallback."
  (let ((appearance (my/get-system-appearance)))
    ;; Disable all currently enabled themes to prevent conflicts
    (mapc #'disable-theme custom-enabled-themes)
    (pcase appearance
      ('dark
       (load-theme dark-theme t))
      ('light
       (load-theme light-theme t))
      (_
       ;; If we cannot detect the theme, default to light 
       (load-theme light-theme t)))))

;; Apply theme at startup
(my/set-theme-based-on-appearance)

;; ===========================
;; UI Customizations
;; ===========================

;; Disable unnecessary UI elements
(tool-bar-mode -1)           ;; Hide the toolbar
(menu-bar-mode -1)           ;; Hide the menu bar
(scroll-bar-mode -1)         ;; Hide the scroll bar

;; Enable useful UI features
(column-number-mode 1)       ;; Show column numbers
(global-display-line-numbers-mode 1) ;; Enable global line numbers

;; Enable visual line mode globally
(global-visual-line-mode 1)

;; Set Default Font to Iosevka 18pt
;;(set-face-attribute 'default nil :family "Iosevka" :height 150)
;; Set font
(set-face-attribute 'default nil
  :family "JetBrains Mono Nerd Font"
  :height 140 
  :weight 'normal
  :width 'normal)
;; Line spacing 
(setq-default line-spacing 0)

;; Backup files -> ~/.emacs.d/backups/
(setq backup-directory-alist `(("." . "~/.emacs.d/backups"))
      backup-by-copying t    ;; Don't delink hardlinks
      version-control t      ;; Use version numbers on backups
      delete-old-versions t  ;; Automatically delete excess backups
      kept-new-versions 6
      kept-old-versions 2)

;; ===========================
;; macOS Specific Settings
;; ===========================
(when (eq system-type 'darwin)
  ;; Use Command key as Meta
  (setq mac-command-modifier 'meta
        mac-option-modifier 'none)

  ;; Better font rendering on macOS
  (setq ns-use-srgb-colorspace t)
  ;; Add homebrew
  (add-to-list 'exec-path "/opt/homebrew/bin")
  )

;; ===========================
;; Evil Mode Configuration
;; ===========================
(use-package evil
  :ensure t
  :init
  (setq evil-want-integration t)
  (setq evil-want-keybinding nil)
  :config
  (evil-mode 1)) ;; Enable Evil Mode globally

(use-package evil-collection
  :init
  :after evil
  :ensure t
  :config
  (evil-collection-init))

(keymap-global-set "C-u" 'evil-scroll-up)

;; ===========================
;; Additional Packages
;; ===========================

;; Install and enable Helm
(use-package helm
  :config
  (helm-mode 1))

;; Install and enable Company Mode globally
(use-package company
  :init
  (global-company-mode 1)
  :config
  ;; Integrate Company with LSP
  (setq company-minimum-prefix-length 1
        company-idle-delay 0.0)) ;; Show completions immediately

;; Install and configure Projectile
(use-package projectile
  :init
  (projectile-mode +1)
  :bind (:map projectile-mode-map
              ("s-p" . projectile-command-map)))

;; Install and bind Magit
(use-package magit
  :bind ("C-x g" . magit-status))

;; Install and enable Which-Key
(use-package which-key
  :config
  (which-key-mode))

;; ===========================
;; LSP Configuration
;; ===========================
(use-package lsp-mode
  :hook ((python-mode . lsp)
         (kotlin-mode . lsp)
         (c++-mode . lsp)
         (c-mode . lsp)
         (rust-mode . lsp))
  :commands lsp
  :config
  (setq lsp-prefer-flymake nil) ;; Use lsp-ui and flycheck instead of flymake
  (setq lsp-enable-snippet t) ;; Disable snippet support if not needed
  (setq lsp-headerline-breadcrumb-enable nil)) ;; Disable breadcrumb for performance

(use-package lsp-ui
  :commands lsp-ui-mode
  :config
  (setq lsp-ui-doc-enable t
        lsp-ui-doc-delay 0.2
        lsp-ui-sideline-enable t
        lsp-ui-imenu-enable t))

(use-package lsp-treemacs
  :commands lsp-treemacs-errors-list)

(use-package flycheck
  :init (global-flycheck-mode))

;; ===========================
;; Language-Specific Configurations
;; ===========================

;; Python
(use-package lsp-pyright
  :ensure t
  :custom (lsp-pyright-langserver-command "pyright") ;; or basedpyright
  :hook (python-mode . (lambda ()
                          (require 'lsp-pyright)
                          (lsp))))  ; or lsp-deferred
(use-package python
  :ensure nil
  :hook (python-mode . lsp)
  :config
  (setq python-shell-interpreter "python3")
  )

(use-package poetry :ensure t)

;; Kotlin
(use-package kotlin-mode
  :mode "\\.kt\\'"
  :config
  )

;; C++
(use-package cc-mode
  :ensure nil
  :config
  )

;; Rust
(use-package rust-mode
  :hook (rust-mode . lsp)
  :config
  (setq rust-format-on-save t)
  )

(message "Emacs init loaded.")
(custom-set-variables
 ;; custom-set-variables was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 '(helm-minibuffer-history-key "M-p")
 '(package-selected-packages
   '(catppuccin-theme lsp-pyright zenburn-theme which-key solarized-theme rust-mode projectile poetry magit lsp-ui lsp-treemacs kotlin-mode helm flycheck evil-collection dracula-theme company better-defaults)))
(custom-set-faces
 ;; custom-set-faces was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 )