#!/bin/sh

dry_run() { [ -n "$DRY_RUN" ]; }

usage() {
    echo "Usage: $(basename $0) [-h] [-f]"
    echo ""
    echo "  -h  print this help and exit"
    echo "  -f  modify filesystem rather than dry run"
}

###############################################################################
# Helper Functions
###############################################################################

if [ -t 1 ]; then
    rst=$(tput      sgr0)
    red=$(tput      setaf  1)
    green=$(tput    setaf  2)
    yellow=$(tput   setaf  3)
    blue=$(tput     setaf  4)
    magenta=$(tput  setaf  5)
    cyan=$(tput     setaf  6)
else
    rst=''
    red=''
    green=''
    yellow=''
    blue=''
    magenta=''
    cyan=''
fi

heading()   { printf '%s\n' "${blue}=====  $1  ==========${rst}"; }
info()      { printf '%s ' "$@";                        printf '\n'; }
ok()        { printf '%s ' "${green}OK:${rst}" "$@";    printf '\n'; }
warn()      { printf '%s ' "${yellow}$@${rst}";         printf '\n'; }
error()     { printf '%s ' "${red}$@${rst}";            printf '\n'; }

is_installed() {
    command -v nvim >/dev/null 2>&1
}

greeting() {
    dry_run && info "Dry run: no changes will be made to filesytem (use -f to override)."
    info "Deploying with git user $yellow${GIT_USER:-$DEFAULT_GIT_USER} <${GIT_EMAIL:-$DEFAULT_GIT_EMAIL}>$rst"
    [ -t 0 ] && {
        info "Press ENTER to continue (CTRL-C to cancel)..."
        read k
    }
}

# Make sure directory $1 exists.
ensure_directory() {
    if [ -d "$1" ]; then
        ok "$1/"
    else
        warn "creating $1/"
        dry_run || mkdir -p "$1/"
    fi
}

# Make sure file $1 does not exist.
remove_file() {
    if [ ! -f "$1" ]; then
        ok "$1"
    else
        warn "removing $1"
        dry_run || rm "$1"
    fi
}

# Make sure file $1 exists (content is irrelevant).
touch_file() {
    if [ -f "$1" ]; then
        ok "$1"
    else
        warn "creating $1"
        dry_run || touch "$1"
    fi
}

# Remove $1 if it's a broken link to a dotfile script.
prune_cmd() {
    if [ -h "$1" ]; then  # it's a symbolic link...
        target="$(readlink "$1")"
        case "$target" in
            "$DOTFILES/bin/"*)  # ... pointing into dotfiles bin
                if [ ! -e "$1" ]; then  # target of the link missing
                    warn "removing stale link $1 -> $target"
                    dry_run || rm -f "$1"
                fi
                ;;
        esac
    fi
}

# Make sure $2 is a link to $1.
link() {
    target="$(realpath -s "$1")"
    if [ "$(readlink "$2")" = "$target" ]; then
        ok "$2"
    else
        warn "linking $2 -> $target"
        dry_run || ln -sf "$target" "$2"
    fi
}

# Ensure $1 and $2 contents are equal, updating $1 if needed.
equal_content() {
    if diff "$1" "$2" >/dev/null 2>&1; then
        ok "$1"
    else
        warn "overwriting $1 with $2:"
        cat "$2"
        dry_run || cp -f "$2" "$1"
    fi
}

###############################################################################
# Configuration Deployments
###############################################################################

deploy_alacritty() {
    heading 'alacritty'
    ensure_directory "$XDG_CONFIG_HOME/alacritty"
    link "$DOTFILES/alacritty/alacritty.yml" "$XDG_CONFIG_HOME/alacritty/alacritty.yml"
}

deploy_bash() {
    heading 'bash'
    for f in .bash_logout .profile; do remove_file "$HOME/$f"; done
    ensure_directory "$XDG_DATA_HOME/bash"  # for history
    ensure_directory "$XDG_DATA_HOME/bash-completion/completions"
    link "$DOTFILES/bash/bashrc" "${HOME}/.bashrc"
    link "$DOTFILES/bash/bash_profile" "${HOME}/.bash_profile"
}

deploy_bin() {
    heading 'bin'
    ensure_directory "$HOME/.local/bin"
    for cmd in $HOME/.local/bin/*; do prune_cmd "$cmd"; done
    for cmd in "$DOTFILES/bin/"*; do
        link "$cmd" "$HOME/.local/bin/$(basename "$cmd")"
    done
}

deploy_git() {
    heading 'git'
    ensure_directory "$XDG_CONFIG_HOME/git"
    ensure_directory "${HOME}/.local/etc/git"
    link "$DOTFILES/git/gitconfig" "$XDG_CONFIG_HOME/git/config"
    link "$DOTFILES/git/gitignore" "$XDG_CONFIG_HOME/git/ignore"

    temp_git="$(mktemp)"
    cat >"$temp_git" <<EOF
#         *************************************
#         *       DO NOT EDIT THIS FILE       *
#         *************************************
#
# This file was generated by the bootstrap script and any changes will be
# overwritten the next time it is run. For local settings, use this instead:
#
#   ~/.local/etc/git/config
#
EOF
    git config -f "$temp_git" user.name "${GIT_USER:-$DEFAULT_GIT_USER}"
    git config -f "$temp_git" user.email "${GIT_EMAIL:-$DEFAULT_GIT_EMAIL}"
    equal_content "$HOME/.local/etc/git/config.user" "$temp_git"
}

deploy_jupyter() {
    heading 'jupyter'
    ensure_directory "${HOME}/.jupyter/custom"
    ensure_directory "${HOME}/.jupyter/nbconfig"
    link "$DOTFILES/jupyter/custom.js" "${HOME}/.jupyter/custom/custom.js"
    link "$DOTFILES/jupyter/notebook.json" "${HOME}/.jupyter/nbconfig/notebook.json"
}

deploy_mintty() {
    heading 'mintty'
    ensure_directory "$XDG_CONFIG_HOME/mintty"
    link "$DOTFILES/mintty/minttyrc" "$XDG_CONFIG_HOME/mintty/config"
}

deploy_misc() {
    heading 'miscelaneous'
    ensure_directory "$XDG_DATA_HOME/less"  # for history
    touch_file "$HOME/.hushlogin"
}

deploy_nvim() {
    heading 'nvim'
    ensure_directory "$XDG_CONFIG_HOME/nvim/autoload"
    ensure_directory "$XDG_DATA_HOME/nvim/plugged"
    ensure_directory "$XDG_DATA_HOME/nvim/shada"
    link "$DOTFILES/nvim/plug.vim" "$XDG_CONFIG_HOME/nvim/autoload/plug.vim"
    link "$DOTFILES/nvim/init.vim" "$XDG_CONFIG_HOME/nvim/init.vim"

    if is_installed nvim; then
        warn "installing neovim plugins..."
        dry_run || nvim -nes -u "$XDG_CONFIG_HOME/nvim/init.vim" -c 'PlugInstall | qall!'
    else
        error "neovim is not installed; skipping plugin installation..."
    fi
}

deploy_python() {
    heading 'python'
    ensure_directory "$XDG_CONFIG_HOME/python"
    ensure_directory "$XDG_DATA_HOME/python"  # for history
    link "$DOTFILES/python/startup.py" "$XDG_CONFIG_HOME/python/startup.py"
}

deploy_readline() {
    heading 'readline'
    ensure_directory "$XDG_CONFIG_HOME/readline"
    link "$DOTFILES/readline/inputrc" "$XDG_CONFIG_HOME/readline/inputrc"
}

deploy_ssh() {
    heading 'ssh'
    ensure_directory "${HOME}/.ssh"
    link "$DOTFILES/ssh/ssh_config" "${HOME}/.ssh/config"
}

deploy_tmux() {
    ensure_directory "$XDG_CONFIG_HOME/tmux"
    link "$DOTFILES/tmux/tmux.conf" "$XDG_CONFIG_HOME/tmux/tmux.conf"
}

deploy_x11() {
    heading 'X11'
    link "$DOTFILES/x11/xcompose" ${HOME}/.XCompose
}

deploy_zsh() {
    heading 'zsh'
    ensure_directory "$ZDOTDIR"
    ensure_directory "$XDG_DATA_HOME/zsh"  # for history
    link "$DOTFILES/zsh/zshenv" "$HOME/.zshenv"
    link "$DOTFILES/zsh/zshrc" "$ZDOTDIR/.zshrc"
    link "$DOTFILES/zsh/aliases" "$ZDOTDIR/aliases"
    link "$DOTFILES/zsh/prompt" "$ZDOTDIR/prompt"
    link "$DOTFILES/zsh/solarized" "$ZDOTDIR/solarized"
    link "$DOTFILES/zsh/vi-mode" "$ZDOTDIR/vi-mode"
}