#!/bin/bash
set -euo pipefail

# =============================
# COLORS & LOGGING
# =============================
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m'

log()  { echo -e "${BLUE}[INFO]${NC} $*"; }
ok()   { echo -e "${GREEN}[OK]${NC} $*"; }
warn() { echo -e "${YELLOW}[WARN]${NC} $*"; }
err()  { echo -e "${RED}[ERROR]${NC} $*" >&2; }

# =============================
# CONFIG
# =============================
CONFIG_FILES=(
    ".alias|https://gist.githubusercontent.com/weehongkoh/72bdb76beacacf2ca3dd39a72395b9ee/raw/alias"
    ".func|https://gist.githubusercontent.com/weehongkoh/72bdb76beacacf2ca3dd39a72395b9ee/raw/func"
    ".pathrc|https://gist.githubusercontent.com/weehongkoh/72bdb76beacacf2ca3dd39a72395b9ee/raw/pathrc"
    ".sourcerc|https://gist.githubusercontent.com/weehongkoh/72bdb76beacacf2ca3dd39a72395b9ee/raw/sourcerc"
    ".vimrc|https://gist.githubusercontent.com/weehongkoh/72bdb76beacacf2ca3dd39a72395b9ee/raw/vimrc"
    ".zshrc|https://gist.githubusercontent.com/weehongkoh/72bdb76beacacf2ca3dd39a72395b9ee/raw/zshrc"
)

# =============================
# REQUIREMENTS
# =============================
check_requirements() {
    if [[ $EUID -eq 0 ]]; then
        err "Do not run as root on macOS"
        exit 1
    fi
}

# =============================
# INSTALLATION FUNCTIONS
# =============================
configure_git() {
    log "Configuring Git..."
    read -p "Git name (leave empty to skip): " name
    read -p "Git email (leave empty to skip): " email
    
    if [[ -n "$name" ]]; then
        git config --global user.name "$name"
    fi
    if [[ -n "$email" ]]; then
        git config --global user.email "$email"
    fi
    ok "Git configured"
}

install_oh_my_zsh() {
    if [[ -d "$HOME/.oh-my-zsh" ]]; then
        ok "Oh My Zsh already installed"
        return
    fi
    
    log "Installing Oh My Zsh..."
    RUNZSH=no CHSH=no KEEP_ZSHRC=yes \
        sh -c "$(curl -fsSL https://raw.githubusercontent.com/ohmyzsh/ohmyzsh/master/tools/install.sh)"
    ok "Oh My Zsh installed"
}

install_plugins() {
    log "Installing plugins..."
    local dir="${ZSH_CUSTOM:-$HOME/.oh-my-zsh/custom}/plugins"
    [[ -d "$dir/zsh-autosuggestions" ]] || git clone https://github.com/zsh-users/zsh-autosuggestions "$dir/zsh-autosuggestions"
    [[ -d "$dir/zsh-syntax-highlighting" ]] || git clone https://github.com/zsh-users/zsh-syntax-highlighting "$dir/zsh-syntax-highlighting"
    ok "Plugins installed"
}

install_theme() {
    log "Installing Spaceship theme..."
    local themes="${ZSH_CUSTOM:-$HOME/.oh-my-zsh/custom}/themes"
    local dir="$themes/spaceship-prompt"
    [[ -d "$dir" ]] || git clone https://github.com/spaceship-prompt/spaceship-prompt.git "$dir" --depth=1
    ln -sf "$dir/spaceship.zsh-theme" "$themes/spaceship.zsh-theme"
    ok "Theme installed"
}

clean_macos_aliases() {
    local alias_file="$HOME/.alias"
    if [[ -f "$alias_file" ]]; then
        log "Patching .alias for macOS (removing apt-get and xclip blocks)..."
        
        # Delete the multiline apt-get block (from the comment down to the final command)
        sed -i '' '/# System update & cleanup/,/sudo apt-get clean/d' "$alias_file"
        
        # Delete the xclip block
        sed -i '' '/# xclip shortcuts/,/xclip -selection clipboard/d' "$alias_file"
        
        ok "macOS incompatibilities removed from .alias"
    fi
}

download_configs() {
    log "Downloading custom config files..."
    local backup="$HOME/.config_backup_$(date +%Y%m%d_%H%M%S)"
    mkdir -p "$backup"
    
    for entry in "${CONFIG_FILES[@]}"; do
        local f="${entry%%|*}"
        local url="${entry##*|}"
        
        if [[ -f "$HOME/$f" ]]; then
             cp "$HOME/$f" "$backup/"
        fi
        log "Fetching $f ..."
        curl -fsSL "$url" -o "$HOME/$f" || warn "Failed to download $f"
    done
    
    # Automatically clean up the macOS incompatible aliases after downloading
    clean_macos_aliases
    
    ok "Configs downloaded (Backup at $backup)"
}

update_zshrc() {
    local zshrc="$HOME/.zshrc"
    log "Updating .zshrc..."
    
    if [[ ! -f "$zshrc" ]]; then
        warn ".zshrc not found, creating new one..."
        touch "$zshrc"
    fi

    # macOS BSD sed requires '-i ''' for in-place editing
    grep -q 'ZSH_THEME="spaceship"' "$zshrc" || sed -i '' 's/ZSH_THEME=".*"/ZSH_THEME="spaceship"/' "$zshrc"
    grep -q 'zsh-autosuggestions' "$zshrc" || sed -i '' 's/plugins=(/plugins=(zsh-autosuggestions /' "$zshrc"
    grep -q 'zsh-syntax-highlighting' "$zshrc" || sed -i '' 's/plugins=(/plugins=(zsh-syntax-highlighting /' "$zshrc"
    ok ".zshrc updated with plugins and theme"
}

switch_shell() {
    log "Starting Zsh session..."
    echo -e "${YELLOW}Type 'exit' to return to this installer menu.${NC}"
    echo "----------------------------------------"
    zsh -l
    echo "----------------------------------------"
    ok "Returned from Zsh session"
}

# =============================
# INTERACTIVE MENU
# =============================
show_menu() {
    echo "==========================================="
    echo "macOS Zsh Setup - Choose what to do"
    echo "==========================================="
    echo " 0) Run ALL steps (1-7)"
    echo " 1) Configure Git"
    echo " 2) Install Oh My Zsh"
    echo " 3) Install plugins (autosuggestions, syntax highlighting)"
    echo " 4) Install Spaceship theme"
    echo " 5) Download custom configs (~/.alias, .vimrc, etc.)"
    echo " 6) Update ~/.zshrc for plugins & theme"
    echo " 7) Switch to Zsh (Temporary Sub-shell)"
    echo " 8) Quit"
    echo "==========================================="
    echo "Inputs: '0' (All), '1 3 4' (Specific), '0 !1 !5' (All except 1 and 5)"
}

run_choices() {
    local input
    read -p "Select: " input
    input="${input//,/ }" # replace commas with spaces if used

    local -a to_run=()
    local -a to_exclude=()

    # Parse positive selections and negative exclusions
    for item in $input; do
        if [[ "$item" == !* ]]; then
            to_exclude+=("${item:1}") # Strip the '!' character
        elif [[ "$item" == "0" ]]; then
            to_run+=(1 2 3 4 5 6 7)
        else
            to_run+=("$item")
        fi
    done

    # Protect against empty arrays crashing older bash versions with 'set -u'
    if [[ ${#to_run[@]} -gt 0 ]]; then
        for choice in "${to_run[@]}"; do
            
            local skip=false
            if [[ ${#to_exclude[@]} -gt 0 ]]; then
                for ex in "${to_exclude[@]}"; do
                    if [[ "$choice" == "$ex" ]]; then
                        skip=true
                        break
                    fi
                done
            fi
            
            $skip && continue

            case "$choice" in
                1) configure_git ;;
                2) install_oh_my_