#!/bin/bash

# TODO:
# unzip command
# export mods
# import mods

RED='\033[0;31m'
GREEN='\033[0;32m'
ORANGE='\033[0;33m'
NC='\033[0m'

H2PATH="./h2path"
MODS_DIR=""
DB_FILE=""

function get_basename() {
    base_name=$(echo "$1" | sed -E 's/\.+.*//')
}

function find_game_directory() {
    local search_dir="/"
    local target_dir="Steam/steamapps/common/Helldivers\ 2/data"

    echo "--- /// HELLDIVERS 2 MOD MANAGER /// ---" >&2

    # check if path is saved
    if [[ -f "$H2PATH" ]]; then
        saved_dir=$(cat "$H2PATH")
        if [[ -d "$saved_dir" ]]; then
            echo "Using saved game directory \$MODS_DIR: $saved_dir" >&2
            echo "$saved_dir"
            return
        else
            echo "Saved game directory is invalid"
        fi
    fi

    # first time setup, or directory is not valid anymore
    echo "Searching for the Helldivers 2 data directory..." >&2
    game_dir=$(find "$search_dir" -type d -path "*/$target_dir" 2>/dev/null | head -n 1)

    if [[ -z "$game_dir" ]]; then
        echo "Could not find the Helldivers 2 data directory automatically" >&2
        read -p "Please enter the path to the Helldivers 2 data directory: " game_dir
        if [[ ! -d "$game_dir" ]]; then
            echo -e "${RED}Error${NC}: Provided path is not a valid directory"
            exit 1
        fi
    fi

    echo "$game_dir" > "$H2PATH"
    echo -e "Game directory ${GREEN}saved{$NC} to: $H2PATH" >&2
    echo "--- /// ---" >&2
    echo "$game_dir"
}

function initialize_directories() {
    MODS_DIR=$(find_game_directory)
    DB_FILE="$MODS_DIR/mods.csv"

    if [[ ! -f "$DB_FILE" ]]; then
        touch "$DB_FILE"
        echo "Database file created at: $DB_FILE"
    fi

    echo "--- /// MODS /// ---" >&2
}

function display_help() {
    echo "Helldivers 2 Mod Manager"
    echo "Usage: h2mm [command] [options]"
    echo "Commands:"
    echo "  install -n \"<mod_name>\" <mod_files>       Install a mod with a name and files"
    echo "  list                                        List all installed mods"
    echo "  uninstall -n \"<mod_name>\"                 Uninstall a mod by name"
    echo "  export \"<zip_name>\"                       Export installed mods to a zip file"
    echo "  import \"<zip_name>\"                       Import mods from a zip file"
    echo "  help                                        Display this help message"
    echo "For more information, use h2mm [command] --help"
    echo "Basic Usage:"
    echo "  h2mm install -n \"Example mod\" a5f2c029522e6714.patch_0 a5f2c029522e6714.patch_0.stream"
    echo "  h2mm uninstall -n \"Example mod\""
}

function display_install_help() {
    echo "Usage: h2mm install -n \"<mod_name>\" [options] <mod_files>"
    echo "Options:"
    echo "  -n \"<mod_name>\"       Name of the mod (MANDATORY), inside double quotes"
    echo "  -d <mod_dir>        Directory containing mod files"
    echo "  -z <mod_zip>        Zip file containing mod files (.zip, .rar)"
    echo "  <mod_files>         List of mod files to install"
    echo "Usage:"
    echo "  h2mm install -n \"Example mod\" a5f2c029522e6714.patch_0 a5f2c029522e6714.patch_0.stream"
    echo "  h2mm install -n \"Example mod\" a5f* (using a wildcard to include all files)"
    echo "  h2mm install -n \"Example mod\" -d /path/to/mod/files"
    echo "  h2mm install -n \"Example mod\" -z /path/to/mod.zip"
}

function display_uninstall_help() {
    echo "Usage: h2mm uninstall [options]"
    echo "Options:"
    echo "  -n \"<mod_name>\"       Name of the mod to uninstall"
    echo "  -i <index>          Index of the mod to uninstall"
    echo "Usage:"
    echo "  h2mm uninstall -n \"Example mod\""
    echo "  h2mm uninstall -i 1"
}

function install_mod() {
    local mod_name=""
    local mod_files=()
    local mod_dir=""

    # parse arguments
    while [[ $# -gt 0 ]]; do
        case "$1" in
            -n)
                mod_name="$2"
                shift 2
                ;;
            -d)
                mod_dir="$2"
                shift 2
                ;;
            -z)
                mod_zip="$2"
                shift 2
                ;;
            --help)
                display_install_help
                exit 0
                ;;
            *)
                mod_files+=("$1")
                shift
                ;;
        esac
    done

    # zip file containing mod files
    if [[ -n "$mod_zip" ]]; then
        if ! command -v unzip &> /dev/null; then
            echo -e "${RED}Error${NC}: unzip is not installed, please install the package and try again"
            exit 1
        fi
        temp_dir=$(mktemp -d)
        unzip "$mod_zip" -d "$temp_dir"
        mod_files+=$(find "$temp_dir" -type f -name "*.patch_*")
        rm -rf "$temp_dir"
    fi

    # directory containing mod files
    if [[ -n "$mod_dir" ]]; then
        # mod_files+=$(find "$mod_dir" -type f -name "*.patch_*")
        readarray -d '' mod_files < <(find "$mod_dir" -type f -name "*.patch_*" -print0)
    fi
    
    if [[ -z "$mod_name" || ${#mod_files[@]} -eq 0 ]]; then
        echo -e "${RED}Error${NC}: Mod name and files are required."
        exit 1
    fi

    # verify mod files exist
    for file in "${mod_files[@]}"; do
        if [[ ! -f "$file" ]]; then
            echo -e "${RED}Error${NC}: File $file does not exist"
            exit 1
        fi
    done

    declare -A patch_count # hash table - in case multiple named files are needed for 1 mod install, store the patch count
    target_files=()
    for file in "${mod_files[@]}"; do
        get_basename "$file"
        patch_prefix="$MODS_DIR/${base_name}.patch_"
        count=$(ls "${patch_prefix}"* 2>/dev/null | grep -E '([0-9]+$)' 2>/dev/null | wc -l) # count installed patches

        # set patch count for file name
        if [[ -z "${patch_count[$base_name]+unset}" ]]; then
            patch_count["$base_name"]=$count 
        fi

        extension=$(echo "$file" | sed -E 's/.*patch_[0-9]+//')
        target_file="${base_name}.patch_${patch_count[$base_name]}${extension}"
        target_files+=($target_file)

        cp "$file" "$MODS_DIR/$target_file"
        echo -e "Mod file ${ORANGE}$file${NC} installed at ${GREEN}\$MODS_DIR/$target_file${NC}"
    done

    # add entry to database
    next_id=$(awk -F, 'END {print $1 + 1}' "$DB_FILE")
    echo "$next_id,$mod_name,${target_files[*]}" >> "$DB_FILE"
    echo -e "Mod $mod_name ($base_name) ${GREEN}installed successfully${NC}"
}

function list_mods() {
    if [[ ! -s "$DB_FILE" ]]; then
        echo "No mods installed"
        return
    fi

    awk -v color="$GREEN" -v nc="$NC" -F, '{ printf "%s. %s%s%s (%s)\n", $1, color, $2, nc, $3  }' "$DB_FILE"
}

function uninstall_mod() {
    local mod_name=""
    local mod_index=""

    # parse arguments
    while [[ $# -gt 0 ]]; do
        case "$1" in
            -n)
                mod_name="$2"
                shift 2
                ;;
            -i)
                mod_index="$2"
                shift 2
                ;;
            --help)
                display_uninstall_help
                exit 0
                ;;
            *)
                echo -e "${RED}Error${NC}: Invalid argument $1"
                exit 1
                ;;
        esac
    done

    if [[ -z "$mod_name" && -z "$mod_index" ]]; then
        echo -e "${RED}Error${NC}: Mod name or index is required to uninstall"
        exit 1
    fi

    # find mod files
    if [[ -n "$mod_index" ]]; then
        entry=$(grep "^${mod_index}," "$DB_FILE")
        mod_name=$(echo "$entry" | awk -F, '{print $2}')
    elif [[ -n "$mod_name" ]]; then
        entry=$(grep -i ",$mod_name," "$DB_FILE")
        mod_index=$(echo "$entry" | awk -F, '{print $1}')
    fi

    if [[ -z "$entry" ]]; then
        echo -e "${RED}Error${NC}: Mod not found"
        exit 1
    fi

    # delete mod files
    files=$(echo "$entry" | cut -d',' -f3- | tr ',' ' ')
    declare -A downgrades
    for file in $files; do
        echo -e "Removing ${YELLOW}\$MODS_DIR/$file${NC}"
        rm -f "$MODS_DIR/$file"

        get_basename "$file"
        current_version=$(echo $file | grep -oP '(?<=patch_)\d+')
        downgrades["$base_name"]=current_version
    done

    # downgrade any necessary mods
    for file in "${!downgrades[@]}"; do
        # find all files that have the same base name, and are greater than the current version, and downgrade them
        get_basename "$file"
        same_patches=$(ls "$MODS_DIR/${base_name}.patch_"* 2>/dev/null | grep -Eo "$base_name.*")

        for patch in $same_patches; do
            patch_version=$(echo $patch | grep -oP '(?<=patch_)\d+')
            if [[ $patch_version -gt ${downgrades[$file]} ]]; then
                new_version=$((patch_version - 1))
                extension=$(echo "$patch" | sed -E 's/.*patch_[0-9]+//')

                new_patch="${base_name}.patch_${new_version}${extension}"
                mv "$MODS_DIR/$patch" "$MODS_DIR/$new_patch"
                echo -e "Downgraded ${ORANGE}$patch${NC} to ${GREEN}\$MODS_DIR/$new_patch${NC}"
                
                # save changes in database as well
                sed -i "s/$patch/$new_patch/" "$DB_FILE"
            fi
        done
    done

    # remove entry from database
    sed -i "/^$mod_index/d" "$DB_FILE"

    echo -e "Mod ${GREEN}uninstalled successfully${NC}"
}

# main
if [[ $# -lt 1 ]]; then
    display_help
    exit 1
fi

command="$1"
shift

initialize_directories

case "$command" in
    install)
        install_mod "$@"
        echo "--- /// ---"
        ;;
    list)
        list_mods
        echo "--- /// ---"
        ;;
    uninstall)
        uninstall_mod "$@"
        echo "--- /// ---"
        ;;
    *)
        display_help
        ;;
esac