#!/bin/bash
# set -x

source ./general_utils
source ./log_helpers
source ./git_helpers

# source ./update_helpers.sh
# source ./opkg_helpers.sh
source ./update_psa_helpers

source ./read_config

###############################################################################
# update_psa
# 
# Implementing the UpdateController (see below). UpdateController is waiting
# for an external trigger by the DeviceController (DC). The trigger is sent via
# an UNIX-pipe (=fifo). When DC triggers UpdateController, it has to check if
# an update is possible, i.e. is has to lock the PSA for the update procedure.
# UpdateController will send back the update-result to DeviceController
# which unlocks the PSA to return to nomal operation.
#
# If UpdateController has been triggered, it checks out a predefined git-
# repository. As a sanity check it makes sure that there are some changes in 
# the repository. In case there are no changes, it issues an error message
# to DC and returns to its wait-state.
#
# Otherwise it checks if the changed files are correct (using md5) and if
# the new files are valid for the PSA. If there is some problem, it issues an
# error message to DC, reverts the git-repository to its previous state and
# returns to its wait-state.
#
# Otherwise it makes a backup of the current state of the PSA, and if there
# are opkg-packages to install it runs a dry installation process using opkg.
# In case of error, it issues an error message to DC, deletes the backup,
# reverts # the git-repository to its previous state and returns to its
# wait-state.
#
# Otherwise, it copies all new files to their target locations and in case
# of opkg-packages, it installs the packages.
#
# In case of error it restores the previous state using the backup and 
# reinstalls the previous opkg-package(s). It issues an error message to
# DC and returns to its wait-state.
#
# Otherwise the update went well, and it does some cleanup, sends a success
# message to DC and returns to its wait-state. 
#                                                                           
###############################################################################
#                                                                             
#                            UPDATE PROCEDURE
#                                                                           
###############################################################################
update() {
    local try_update_count=0
    local func="${FUNCNAME[0]}"

    # read config parameters
    # read_config
                
    log_debug "$func:${LINENO}: fetch/merge updates..."
   
    # Fetch new updates (using git)
    while :
    do
        local repository_is_already_up_to_date=""
        if ! fetch_customer_updates repository_is_already_up_to_date; then
            if [ "$repository_is_already_up_to_date" = "yes" ]; then
                log_error "$func:${LINENO}: $customer_id is up-to-date"\
                    "-> no files to update -> no psa update"
                exit 1
            fi
            try_updates_count=$((try_updates_count+1))
            if [[ "$try_updates_count" -eq 5 ]]; then
                log_error "$func:${LINENO}: fetch/merging failed" ; exit 1
            fi
            sleep 60s
        else
            # Fetched updates successfully 
            try_updates_count=0
            break
        fi
    done

    # TODO: backup implementieren
    # Backup before any updates in case some previous test was wrong
    if ! backup_previous_version; then
        log_error "$func:${LINENO}: backup failed"
        revert_customer_repository ; exit 1
    fi

    local changed_files=$(changed_file_names)
    local conf_ini_files=$(filter_conf_ini_files "$changed_files")

    # check if *.conf and/or *.ini-files have to md5-sum as denoted
    # in update.conf
    if ! check_md5_for_changed_conf_and_ini_files "$conf_ini_files" ; then
        log_error "$func:${LINENO}: new customer files wrong"
        revert_customer_repository ; exit 1
    fi
    
    # copy *.conf and/or *.ini-files to their corresponding system-directories
    if ! copy $conf_ini_files; then
        log_error "$func:${LINENO}: copy operation failed"
        revert_customer_repository ; exit 1
    fi

    # check if the opkg-command-file has been changed during 'git pull'
    if grep -qE ".*opkg_commands.*?" <<< $changed_files; then
        # read opkg_cmds: each line respresents an opkg-command
        readarray opkg_commands < <(cat $opkg_cmds_file)
        for opkg_c in "${opkg_commands[@]}"; do
            if grep -qE "^\s*[#]+.*$" <<< $opkg_c; then
                continue    # found comment line
            fi

            # package manipulation commands without package:
            local cwp="update|upgrade|clean"
            # informational commands without package:
            cwp="${cwp}|list|list-installed|list-upgradable"

            if grep -qE "^.*\s+($cwp)\s+.*$" <<< $opkg_c; then
                local p=$(printf '%s' "$opkg_c" | awk '{ print $NF }')
                local opkg_output=()
                if ! exec_opkg_info "$p" opkg_output; then
                    log_error "$func:${LINENO}: opkg info $opkg_c failed"
                    revert_customer_repository ; exit 1
                fi

                if ! check_md5_for_opkg_packages opkg_output; then
                    log_error "$func:${LINENO}: "\
                        "wrong md5sum for opkg packages"
                    revert_customer_repository ; exit 1
                fi
            fi
            
            # perform a dry-run and check if everything might work as expected. 
            if ! exec_opkg_noaction $opkg_c; then
                    log_error "$func:${LINENO}: "\
                        "opkg --noaction $opkg_c failed"
            fi

            # Actually execute the opkg command
            if ! exec_opkg $opkg_c; then
                log_error "$func:${LINENO}: exec_opkg $opkg_c failed"
                fallback_to_previous_version
                revert_customer_repository ; exit 1
            fi
        done
    else
        log_info "$func:${LINENO}: no opkg commnds to execute"
    fi
    
    # Cleanup.
    if ! cleanup_previous_version; then
        log_error "$func:${LINENO}: cleanup_previous_version failed"
    fi
            
    log_info "$func:${LINENO}: success"
    exit 0
}

###############################################################################

if [ -z $IFS ]; then
    IFS=$'\n'
fi

readonly PROGRAM=`basename $0`
readonly VERSION="0.8.0"

config_filename=""

while test $# -gt 0; do
    case $1 in
        --file | --fil | --fi | --f | -file | -fil | -fi | -f )
            __conf_file=yes
            ;;
        --help | -hel | --he | --h | '--?' | -help | -hel | -he | -h | '-?' )
            usage_and_exit 0
            ;;
        --version | --versio | --versi | --vers | --ver | --ve | --v | \
        -version | -versio | -versi | -vers | -ver | -ve | -v )
            version
            ;;
        --dbg | --db | --d | -dbg | -db | -d )
            set_dbg_level $DEBUG
            ;; 
        -*)
            error "Unrecognized option: $1"
            ;;
        *)
            if [ "$__conf_file" = "yes" ]; then
                config_filename="$1"
                __conf_file=""
            else
                error "Unrecognized parameter string: $1"
            fi
            break
            ;;
    esac
    shift
done

if ! [ -z "$config_filename" ]; then
    if read_config "$config_filename" ; then
        # set -x
        if clone_customer_repository $customer_repository_path ; then 
            check_sanity_of_repository
            update 
        fi
    fi
else
    error "config-file missing"
fi