#!/bin/bash

INTERACTIVE=1
ARCH=""
PUBLIC_ACCESS="false"
DATA_DIR="$PWD/data"
PORT="8080"
HOST="127.0.0.1"
VERSION=""
JWT_SECRET=""
ADMIN_PASSWORD=""
ENV_FILE=".env"
ENV_FILE_PATH="/etc/leafwiki/.env"
ENABLE_LINK_REFACTORING="false"
ENABLE_REVISION="false"
MAX_REVISION_HISTORY="100"
RELEASE_LINK="https://github.com/perber/leafwiki/"
PATH_TO_BINARY="/usr/local/bin/leafwiki"


# Usage function
usage() {
    echo "Usage: $0 [--non-interactive [options]] | [interactive mode]"
    echo ""
    echo "Interactive mode (default):"
    echo "  $0"
    echo ""
    echo "Non-interactive mode:"
    echo "  $0 --non-interactive -env-file|--env-file <path to an env file> "
    echo ""
    echo "Environment file:"
    echo "  You can specify an env file with --env-file."
    echo "  See .env.example for available variables."
    echo ""
    echo "  -help, --help                 Display this help message"
    exit 1
}

check_dependencies() {
    if ! command -v $1 &> /dev/null; then
        echo "Error: ${1} is not installed. Please install ${1} and try again."
        exit 1
    fi
}

validate_architecture(){
    if [[ "$ARCH" != "amd64" && "$ARCH" != "arm64" ]]; then
        echo "Error: Unsupported architecture '$ARCH'. Supported values are: amd64, arm64"
        usage
        exit 1
    fi
}

validate_port(){
    if ! [[ "$PORT" =~ ^[0-9]+$ ]] || [ "$PORT" -lt 1 ] || [ "$PORT" -gt 65535 ]; then
        echo "Error: --port requires a valid port number (1-65535)."
        usage
        exit 1
    fi
}

validate_requirements_non_interactive(){
    local var_value="$1"
    local var_name="$2"
    if [[ -z "$var_value" ]]; then
        echo "Error: $var_name environment variable is required in non-interactive mode (set it in the env file used with --env-file)."
        usage
        exit 1
    fi
}

validate_version(){
    if ! [[ "$VERSION" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
        echo "Error: Invalid VERSION format '$VERSION'. Expected format: X.Y.Z"
        exit 1
    fi
}

get_version(){
    if [[ -z "$VERSION" ]]; then
        LATEST_VERSION=$(curl -s https://api.github.com/repos/perber/leafwiki/releases/latest \
        | grep '"tag_name":' \
        | sed -E 's/.*"v([^"]+)".*/\1/')
        VERSION=$LATEST_VERSION
    fi
    validate_version
}

# verify_checksum <file> <url>: compare <file> against the hash published at
# <url>.sha256. Only the hash field is compared, so checksum files that name
# the binary with a "releases/" prefix (older releases) work too.
verify_checksum(){
    local file="$1" url="$2" expected actual
    expected=$(wget -qO- "${url}.sha256" | awk '{print $1}')
    if [[ -z "$expected" ]]; then
        echo "Error: Could not download checksum from ${url}.sha256" >&2
        return 1
    fi
    actual=$(sha256sum "$file" | awk '{print $1}')
    if [[ "$expected" != "$actual" ]]; then
        echo "Error: Checksum mismatch for $(basename "$file") (expected ${expected}, got ${actual})" >&2
        return 1
    fi
}

download_binary(){
    local name="leafwiki-v${VERSION}-linux-${ARCH}"
    local url="${RELEASE_LINK}releases/download/v${VERSION}/${name}"
    wget -O "$name" "$url" || exit 1
    if ! verify_checksum "$name" "$url"; then
        rm -f "$name"
        exit 1
    fi
    cp "$name" $PATH_TO_BINARY
    rm "$name"
    chmod +x $PATH_TO_BINARY
}

check_dependencies "systemctl"
check_dependencies "wget"
check_dependencies "sha256sum"

# Check if --non-interactive flag is present
if [[ "$*" == *"--non-interactive"*  ||  "$*" == *"-non-interactive"* ]]; then
    INTERACTIVE=0
fi

if [[ "$INTERACTIVE" -eq 0 && "$*" != *"--env-file"* && "$*" != *"-env-file"* ]]; then
    echo "Error: In non-interactive mode, --env-file is required"
    usage
    exit 1
fi

if [[ "$INTERACTIVE" == 0 ]]; then

    while [[ $# -gt 0 ]]; do
        case "$1" in 
            -non-interactive|--non-interactive)
                shift
                ;;
            -env-file|--env-file)
                if [[ -z "$2" ]]; then
                    echo "Error: --env-file requires a path argument"
                    usage
                fi
                if [[ ! -f "$2" ]]; then
                    echo "Error: Environment file '$2' does not exist or is not a regular file"
                    exit 1
                fi
                ENV_FILE_PATH="$(realpath "$2")"
                ENV_FILE="$(basename "$2")"
                if [[ ! -r "$ENV_FILE_PATH" ]]; then
                    echo "Error: Cannot read env file '$ENV_FILE_PATH'"
                    exit 1
                fi
                # Source the environment file and parse each variable
                while IFS= read -r line || [[ -n "$line" ]]; do
                    # Skip empty lines and comments
                    [[ "$line" =~ ^[[:space:]]*$ || "$line" =~ ^[[:space:]]*# ]] && continue
                    
                    # Extract key=value pairs
                    [[ "$line" =~ ^([A-Za-z_][A-Za-z0-9_]*)=(.*)$ ]] || continue
                    
                    key="${BASH_REMATCH[1]}"
                    value="${BASH_REMATCH[2]}"
                    
                    # Remove surrounding quotes (both single and double)
                    value="${value%\"}"
                    value="${value#\"}"
                    value="${value%\'}"
                    value="${value#\'}"
                    
                    # Export the variable
                    export "$key=$value"
                done < "$ENV_FILE_PATH"
                shift 2
                ;;
            *)
                echo "Error: Unknown option '$1'"
                usage
                ;;
        esac
    done
    
    ARCH="${LEAFWIKI_ARCH:-$ARCH}"
    PUBLIC_ACCESS="${LEAFWIKI_PUBLIC_ACCESS:-$PUBLIC_ACCESS}"
    DATA_DIR="${LEAFWIKI_DATA_DIR:-$DATA_DIR}"
    PORT="${LEAFWIKI_PORT:-$PORT}"
    HOST="${LEAFWIKI_HOST:-$HOST}"
    VERSION="${LEAFWIKI_VERSION:-$VERSION}"
    JWT_SECRET="${LEAFWIKI_JWT_SECRET:-$JWT_SECRET}"
    ADMIN_PASSWORD="${LEAFWIKI_ADMIN_PASSWORD:-$ADMIN_PASSWORD}"
    ALLOW_INSECURE=${LEAFWIKI_ALLOW_INSECURE:-false}
    DISABLE_AUTH=${LEAFWIKI_DISABLE_AUTH:-false}
    ENABLE_REVISION=${LEAFWIKI_ENABLE_REVISION:-false}
    MAX_REVISION_HISTORY=${LEAFWIKI_MAX_REVISION_HISTORY:-"100"}
    ENABLE_LINK_REFACTORING=${LEAFWIKI_ENABLE_LINK_REFACTOR:-false}

    validate_architecture
    validate_requirements_non_interactive "$ARCH" "LEAFWIKI_ARCH"
    validate_requirements_non_interactive "$JWT_SECRET" "LEAFWIKI_JWT_SECRET"
    validate_requirements_non_interactive "$ADMIN_PASSWORD" "LEAFWIKI_ADMIN_PASSWORD"
    validate_port

else
    echo "___________________________________________________"
    echo "|       __               _____       ___ __   _   |";
    echo "|      / /   ___  ____ _/ __/ |     / (_) /__(_). |";
    echo "|     / /   / _ \\/ __ \`/ /_ | | /| / / / //_/ /   |";
    echo "|    / /___/  __/ /_/ / __/ | |/ |/ / / ,< / /    |";
    echo "|.  /_____/\\___/\\__,_/_/    |__/|__/_/_/|_/_/     |";
    echo "|_________________________________________________|";
    echo ""
                                    
    echo "========================================"
    echo "   LeafWiki — Installer"
    echo "========================================"
    echo ""
    echo ""

    read -rp "Which architecture do you want to use? (amd64/arm64): " ARCH
    echo
    read -rsp "Which JWT secret do you want to use: " JWT_SECRET
    echo
    read -rsp "Which admin password do you want to use: " ADMIN_PASSWORD
    echo
    read -rp "Which host do you want to use: " HOST
    echo
    read -rp "Which port do you want to use: " PORT
    echo
    read -rp "Should people without an account have read access? (default: n) y/N: " RESPONSE
    if [[ $RESPONSE == "y" || $RESPONSE == "Y" ]]; then
        PUBLIC_ACCESS="true"
    else
        PUBLIC_ACCESS="false"
    fi

    read -p "Where should the data be saved? (default: $DATA_DIR): " RESPONSE_DATA_DIR
    if [[ -n "$RESPONSE_DATA_DIR" ]]; then
        DATA_DIR="$RESPONSE_DATA_DIR"
    fi

    read -rp "Do you want to enable revision history? (default: n) y/N: " RESPONSE_REVISION
    if [[ $RESPONSE_REVISION == "y" || $RESPONSE_REVISION == "Y" ]]; then

        ENABLE_REVISION="true"

        while true; do
            read -p "Would you specify a max revision number? (default: $MAX_REVISION_HISTORY): " RESPONSE_MAX_REVISION
            if [[ -z "$RESPONSE_MAX_REVISION" ]]; then
                break
            elif [[ "$RESPONSE_MAX_REVISION" =~ ^[0-9]+$ ]]; then
                MAX_REVISION_HISTORY="$RESPONSE_MAX_REVISION"
                break
            else
                echo "Invalid max revision number. Please
                enter an integer greater than or equal to 0, or press Enter to
                keep the default."
            fi
        done
        
    else
        ENABLE_REVISION="false"
    fi
    

    validate_port
    validate_architecture

    mkdir -p "$(dirname "$ENV_FILE_PATH")"
    
    echo "LEAFWIKI_ARCH=\"$ARCH\"" > "$ENV_FILE_PATH"
    echo "LEAFWIKI_PUBLIC_ACCESS=\"$PUBLIC_ACCESS\"" >> "$ENV_FILE_PATH"
    echo "LEAFWIKI_DATA_DIR=\"$DATA_DIR\"" >> "$ENV_FILE_PATH"
    echo "LEAFWIKI_PORT=\"$PORT\"" >> "$ENV_FILE_PATH"
    echo "LEAFWIKI_HOST=\"$HOST\"" >> "$ENV_FILE_PATH"
    echo "LEAFWIKI_JWT_SECRET=\"$JWT_SECRET\"" >> "$ENV_FILE_PATH"
    echo "LEAFWIKI_ADMIN_PASSWORD=\"$ADMIN_PASSWORD\"" >> "$ENV_FILE_PATH"
    echo "LEAFWIKI_ENABLE_REVISION=\"$ENABLE_REVISION\"" >> "$ENV_FILE_PATH"
    echo "LEAFWIKI_MAX_REVISION_HISTORY=\"$MAX_REVISION_HISTORY\"" >> "$ENV_FILE_PATH"

fi

get_version

download_binary

mkdir -p "$DATA_DIR"
RUN_USER="${SUDO_USER:-$USER}"
chown -R "$RUN_USER:$RUN_USER" "$DATA_DIR"
echo "[Unit]
Description=LeafWiki
After=network.target

[Service]
User=$RUN_USER
EnvironmentFile=-${ENV_FILE_PATH:-$(realpath $PWD)/$ENV_FILE}
ExecStart=${PATH_TO_BINARY}
Restart=on-failure

[Install]
WantedBy=multi-user.target
" > /etc/systemd/system/leafwiki.service

systemctl enable leafwiki
systemctl start leafwiki
IS_ACTIVE=$(systemctl is-active leafwiki)
if [[ "$IS_ACTIVE" == "failed" ]]; then
    echo "Installation failed: "
    systemctl status leafwiki
else
    echo "======================================="
    echo "== LeafWiki installation completed!  =="
    echo "==                                   =="
    printf "== %-33s ==\n" "Host: $HOST"
    printf "== %-33s ==\n" "Port: $PORT"
    printf "== %-33s ==\n" "DataDirectory: $DATA_DIR"
    printf "== %-33s ==\n" "Status: $IS_ACTIVE"
    echo "==                                   =="
    echo "======================================="
fi