#!/usr/bin/env bash
set -euo pipefail

source "$PWD/modules/home/bash/bash_funcs"

usage() {
    echo "Usage: $0 [link|remove|update]"
    exit 1
}

# What operation to perform: link, remove, or update.
OP="${1:-}"
if [[ "$OP" == "" ]]; then
    OP="link"
fi
if [[ "$OP" != "link" && "$OP" != "remove" && "$OP" != "update" ]]; then
    usage
fi

GREEN_CHECK="$(printf '\x1b[32m✓\x1b[m')"

BLACK=0
GREEN=2
YELLOW=3
BLUE=4
WHITE=7

# Print a status message with colors.
status() {
    local text="$1"
    local bg_color="$2"
    local fg_color="$3"

    # Convert color numbers to ANSI codes
    local bg_code=$((bg_color < 8 ? bg_color + 40 : bg_color + 92))
    local fg_code=$((fg_color < 8 ? fg_color + 30 : fg_color + 82))

    local padding
    padding=6
    printf "\x1b[1;${bg_code};${fg_code}m %-${padding}s \x1b[m" "$text"
}

# Rendered status messages.
SKIP="$(status "SKIP" "$BLUE" "$WHITE")"
LINKED="$(status "LINKED" "$GREEN" "$BLACK")"
BACKUP="$(status "BACKUP" "$YELLOW" "$BLACK")"
UNLINKED="$(status "UNLINK" "$GREEN" "$BLACK")"

# Create or remove a symlink.
link() {
    local op="$1"
    local source="$PWD/$2"
    local target="$3"

    if [[ $op == "remove" ]]; then
        # Remove symlink.
        if [ -L "$target" ]; then
            rm "$target"
            echo "$UNLINKED $target"
        else
            echo "$SKIP No symlink to unlink at $target"
        fi
    else
        # Create symlink.
        mkdir -p "$(dirname "$target")"
        if [ -L "$target" ] && [ "$(readlink "$target")" = "$source" ]; then
            # Link already exists.
            echo "$SKIP Link $source -> $target exists"
        elif [ -L "$target" ]; then
            # Wrong symlink exists, just replace it.
            ln -sf "$source" "$target"
            echo "$LINKED $1 -> $target (replaced wrong symlink)"
        elif [ -e "$target" ]; then
            # There's a real file/directory there. Back it up, then link.
            mv "$target" "$target.backup.$(date +%s)"
            ln -sf "$source" "$target"
            echo "$BACKUP Linked $source to $target (backed up existing)"
        else
            # Nothing there, create link.
            ln -sf "$source" "$target"
            echo "$LINKED $1 -> $target"
        fi
    fi
}

# Ensure a command exists. If it does not, install it using the given command.
ensure() {
    local name="$1"
    local cmd="$2"
    local script="$3"

    # Require curl for installation checks.
    if ! command -v curl &>/dev/null; then
        printf "curl is not installed. Please install curl first.\n"
        return
    fi

    if ! command -v "$cmd" &>/dev/null; then
        echo "Installing $name..."
        $script
    else
        printf "%s %s is installed.\n" "$GREEN_CHECK" "$name"
    fi
}

# Install a Haskell package using cabal.
cabal_install() {
    local pkg="$1"
    cabal install "$pkg" -j"$(num_cores)" --overwrite-policy=always
}

# Install the V programming language from source.
install_v() {
    local here="$PWD"
    local targetDir="$HOME/src/v"
    rm -rf "$targetDir"
    mkdir -p "$targetDir"
    git clone --depth=1 https://github.com/vlang/v "$targetDir"
    cd "$targetDir"
    make
    sudo ./v symlink
    cd "$here"
}

os="$(which_os)"

# Generally install or update stuff.
if [[ $OP == "update" ]]; then
    ensure "GHCup" "ghcup" "curl --proto '=https' --tlsv1.2 -sSf https://get-ghcup.haskell.org | sh"
    cabal update
    ensure "Fourmolu" "fourmolu" "cabal_install fourmolu"
    ensure "Floskell" "floskell" "cabal_install floskell"
    ensure "V" "v" "install_v"

    printf "\n"

    if [[ "$(which_os)" == "darwin" ]]; then
        ensure "Nix" "nix" "sh <(curl --proto '=https' --tlsv1.2 -L https://nixos.org/nix/install)"
        ensure "Homebrew" "brew" "sh -c \"$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)\""
        ensure "cabal-fmt" "cabal-fmt" "cabal install cabal-fmt -j$(num_cores)"
        brew bundle
    fi
fi

link "$OP" "git/config" "$HOME/.config/git/config"
link "$OP" "rio/config.toml" "$HOME/.config/rio/config.toml"
link "$OP" "crush/config.json" "$HOME/.config/crush/crush.json"
link "$OP" "tmux/tmux.conf" "$HOME/.tmux.conf"
link "$OP" "helix" "$HOME/.config/helix"

# Kitty.
link "$OP" "kitty/kitty.conf" "$HOME/.config/kitty/kitty.conf"
if [[ $os = "darwin" ]]; then
    link "$OP" "kitty/darwin.conf" "$HOME/.config/kitty/os.conf"
else
    link "$OP" "kitty/linux.conf" "$HOME/.config/kitty/os.conf"
fi

link "$OP" "fourmolu/fourmolu.yaml" "$HOME/.config/fourmolu.yaml"