#!/bin/bash

set -ueo pipefail
shopt -s nullglob

declare -r TARGET_PATH="$HOME"
declare -r DOTFILES_ROOT="$PWD"
declare -r SUB="$DOTFILES_ROOT/home/user"

export SUB


declare -r -A TARGETS=(
    ["bash"]=".config/bash .bashrc .profile"
    ["zsh"]="%bash .config/zsh .zshrc .zprofile .zlogout .inputrc"
    ["tmux"]=".tmux.conf"
    ["alacritty"]=".config/alacritty"
    ["nvim"]=".config/nvim .local/bin/vim_askpass_helper .local/bin/vim_askpass_helper_python"
    ["ssh"]=""
    ["less"]=".lesskey"
    ["git"]=".config/git"
    ["ranger"]=".config/ranger"
    ["gpg"]=""
    ["i3"]=".xinitrc .xprofile .Xresources .config/i3 .config/i3status .local/bin/i3status_wrapper .config/rofi .config/picom .local/bin/slm .local/bin/slm_rofi.sh .local/bin/power_rofi.sh .local/bin/wifi .local/bin/bluetooth .local/bin/i3_switch_workspace.sh"
    ["bat"]=".config/bat"
    ["font"]=""
    ["termux"]=""
    ["arch"]=""
    ["psql"]=".psqlrc"
    ["docker"]=".docker/cli-plugins"
    ["ipython"]=".ipython/profile_default/ipython_config.py"
)

_die() {
    echo "$0: $1" >&2
    exit $2
}

test "$0" = "./install" || _die "Error: Please, run this file from root of dotfiles, like this './install.sh TARGET" 1


_link_files_in_sandbox() {
    local targetfile
    for targetfile in "$@"
    do
        echo "installing: $targetfile"
        if [ "${targetfile::1}" = "%" ]; then
            _link_files_in_sandbox ${TARGETS["${targetfile:1}"]}
        else
            if [ ! "$(dirname "$targetfile")" = "." ]; then
                mkdir -p "$SANDBOX_PATH/$(dirname "$targetfile")"
            fi
            ln -sT "$SUB/$targetfile" "$SANDBOX_PATH/$targetfile"
        fi
    done
}

_compare_sandbox_to_home() {
    local comparisons
    comparisons="$(diff -rq "$SANDBOX_PATH" "$TARGET_PATH")"
    echo "$comparisons" | grep -vE "^Only in .+" || true
}

_merge_sandbox_to_home() {
    set +e
    cp -RTnP "$SANDBOX_PATH" "$TARGET_PATH"
    set -e
}

__install_from_sandbox() {
    local comparisons
    comparisons="$(_compare_sandbox_to_home)"

    if [ -n "$comparisons" ]; then
        echo "$comparisons" >&2
        _die "Found conflicting files. Exiting" 1
    fi

    echo "Merging to home..."
    _merge_sandbox_to_home
    echo "Successfully installed"
}

_execute_hook_if_executable() {
    local hook_path="$DOTFILES_ROOT/install-hooks/$1/$2"
    if [ -x "$hook_path" ]; then
        echo "Executing $2 for target '$1'"
        "$hook_path"
    fi
}

execute_pre_hook() {
    _execute_hook_if_executable "$1" "pre-install"
}

execute_post_hook() {
    _execute_hook_if_executable "$1" "post-install"
}

install_target() {
    execute_pre_hook "$1"
    _link_files_in_sandbox ${TARGETS["$1"]}
    __install_from_sandbox
    execute_post_hook "$1"
}

is_target_installed() {
    local not_fully_installed=false

    local targetfile
    for targetfile in ${TARGETS["$1"]}
    do
        if [ "${targetfile::1}" = "%" ]; then
            is_target_installed "${targetfile:1}" || not_fully_installed=true
        else
            if [ ! -e "$TARGET_PATH/$targetfile" ]; then
                echo "$targetfile not linked"
                not_fully_installed=true
            fi
        fi
    done
    if $not_fully_installed; then
        echo "Target '$1' not fully installed"
        echo
        return 1
    fi
    return 0
}

find_targets_that_depend_on() {
    local target
    for target in "${!TARGETS[@]}"
    do
        if [[ " ${TARGETS["$target"]} " =~ " %$1 " ]]; then
            echo "$target"
        fi
    done
}

die_if_installed_targets_depend_on() {
    for reverse_dependecy in $(find_targets_that_depend_on "$1")
    do
        if is_target_installed "$reverse_dependecy" >/dev/null; then
            _die "target '$reverse_dependecy' is depends on installed target '$1'. Exiting..." 1
        fi
    done
}

cmd_unlink() {
    local target targetfile
    for target in "$@"
    do
        die_if_installed_targets_depend_on "$target"

        for targetfile in ${TARGETS["$target"]}
        do
            if [ "${targetfile::1}" = "%" ]; then
                continue
            fi

            if [ -e "$TARGET_PATH/$targetfile" ]; then
                unlink "$TARGET_PATH/$targetfile"
            fi
        done
    done
}

cmd_no_target() {
    _die "TARGET not exists" 1
}

cmd_list() {
    echo "${!TARGETS[@]}"
}

target_exists() {
    [[ " ${!TARGETS[*]} " =~ " $1 " ]]
}

cmd_install() {
    local target
    for target in "$@"
    do
        if target_exists "$target"; then
            SANDBOX_PATH="$(mktemp -td "${USER:-user}.dotfiles_XXXXXXX")"
            export SANDBOX_PATH
            install_target "$target"
            rm -rf "$SANDBOX_PATH"
        else
            cmd_no_target
        fi
    done
}

cmd_help() {
    echo "Dotfiles installation script:
Usage: ./install TARGET...
Usage: ./install unlink TARGET...
Usage: ./install check TARGET
Usage: ./install list"
}

unset executed_command
readonly executed_command="$1"

case "$executed_command" in
    unlink) shift;   cmd_unlink             "$@" ;;
    check) shift;    is_target_installed    "$@" ;;
    list) shift;     cmd_list               "$@" ;;
    help) shift;     cmd_help               "$@" ;;
    *) shift;        cmd_install "$executed_command" "$@" ;;
esac
exit 0