#!/usr/bin/env bash

# TODO: Check installed: git, jq

function detech() {
    command=${@:2}
    log=$1

    "$command" &>$log & disown
}

function die() {
    write_log "Oops: $@" 1>&2 ; exit 1;
}

function get_log_timestamps() {
    $event=$1
    $log_file=$2

    grep -oP "^(\[[0-9]{4}-[0-9]{2}-[0-9]{2} [0-9]{2}:[0-9]{2}:[0-9]{2}\] $event at \K([0-9]{4}-[0-9]{2}-[0-9]{2} [0-9]{2}:[0-9]{2}:[0-9]{2}))$" $log_file
}

function get_os() {
    function get_os_line() {
        file=""
        property=$1

        if [[ -f "/etc/os-release" ]]; then
            file="/etc/os-release"
        elif [[ -f "/usr/etc/os-release" ]]; then
            file="/usr/etc/os-release"
        fi

        if [[ ! -z $file ]]; then
            echo $(grep -oP "(?<=^$property=).+" $file | tr -d '"')
        fi
    }

    os_name=$(get_os_line "NAME")
    os_version=$(get_os_line "VERSION")
    os_pretty=$(get_os_line "PRETTY_NAME")

    if [[ ! -z $os_pretty ]]; then
        echo "$os_pretty"
    elif [[ ! -z $os_name ]]; then
        echo "$os_name $os_version"
    else
        echo "Unknown OS"
    fi
}

function now() {
    echo $(date +"%Y-%m-%d %H:%M:%S")
}

function query_json() {
    echo "$1" | jq $2 -r
}

function split_string() {
    echo $1 | cut -d"$2" -f$3
}

function write_log() {
    echo "[$(now)] $@"
}

function write_separator() {
    char=$1
    echo "$(printf "%0.s$char" {1..80})"
}

payload=$1
service=$2
event=$3
id=$4

started_time=$(now)

base_dir="$(dirname "$(realpath -s "$0")")"
build_base_dir="$base_dir/wd"
log_base_dir="$base_dir/logs"
script_base_dir="$base_dir/repos"

mkdir -p $build_base_dir
mkdir -p $log_base_dir

if [[ -z $event ]]; then
    if [[ ! -z $x_github_event ]]; then
        event=$x_github_event
    else
        die "Missing event"
    fi
fi

if [[ -z $service ]]; then
    service="github"
fi

if [[ -z $id ]]; then
    if [[ ! -z $x_github_delivery ]]; then
        id=$x_github_delivery
    else
        id=$(cat /proc/sys/kernel/random/uuid)
    fi
fi

if [[ ! -z "$payload" ]]; then
    payload_type=$(echo $payload | jq type -r)

    if [[ $? != 0 ]]; then
        die "Bad body format (expecting JSON)"
    else
        if [[ ! $payload_type = "object" ]]; then
            die "Bad body format (expecting JSON object but got $payload_type)"
        fi
    fi
else
    die "Missing payload"
fi

# TODO: Test Gitea
if ! { [[ $service == "github" ]] || [[ $service == "gitea" ]]; }; then
    die "Service '$service' not supported"
fi

repo=$(query_json "$payload" ".repository.full_name")
repo_author=$(split_string $repo "/" 1)
repo_name=$(split_string $repo "/" 2)
instance="$(date +"%y%m%d%H%M%S")_${repo_name}_$id"

script_path="$script_base_dir/$service/$repo_author/$repo_name"
build_path="$build_base_dir/$instance"
log_path="$log_base_dir/$instance.txt"

if [[ -f "$script_path/$event.sh" ]]; then
    script_path="$script_path/$event.sh"
elif [[ -f "$script_path/default.sh" ]]; then
    script_path="$script_path/default.sh"
else
    script_path=""
fi

if [[ ! -z $script_path ]]; then
    function invoke_script() {
        write_log "Started at $(now)"

        export _hook_event=$event
        export _hook_id=$id
        export _hook_payload=$payload
        export _repo_clone_url=$(query_json "$payload" ".repository.clone_url")
        export _wd=$build_path

        export -f query_json
        export -f now
        export -f split_string
        export -f write_log

        write_log "Creating working directory..."
        mkdir -p $build_path

        write_log "Setting path to '$build_path'..."
        cd $build_path

        chmod +x $script_path

        if { [[ $event == "push" ]]; }; then
            export _branch=$(split_string $(query_json "$payload" ".ref") "/" 3)
            export _commit_hash=$(query_json "$payload" ".head_commit.id")
            export _commit_message=$(query_json "$payload" ".head_commit.message")
            export _commit_timestamp=$(query_json "$payload" ".head_commit.timestamp")

            write_log "Cloning repository from '$_repo_clone_url'..."
            git clone --recurse-submodules -q $_repo_clone_url $build_path

            write_log "Resetting repository to '$_commit_hash'..."
            git reset --hard -q $_commit_hash
        fi

        write_log "Executing script..."

        write_separator "="
        $script_path
        write_separator "="

        write_log "Removing working directory..."
        rm -rf $build_path

        write_log "Finished at $(now)"
    }

    detech "$log_path" invoke_script

    echo "    Repo: $service:$repo"
    echo "   Event: $event ($id)"
    echo "Instance: $instance"
    echo "  Script: $script_path"
    echo " Working: $build_path"
    echo "     Log: $log_path"
    echo "    Host: $(hostname) ($(get_os))"
    echo " Started: $started_time"
else
    if [[ $event == "ping" ]]; then
        echo "Pong!"
        echo ""
        echo "If you're seeing this, that means you've done something right. To trigger scripts on events place them in '$script_base_dir/$service/$repo_author/$repo_name/<event>.sh'."
    else
        die "No handler for $event on $service:$repo"
    fi
fi