#!/usr/bin/env bash
#
# Author: Hsieh Chin Fan (typebrook)
# License: MIT
# https://gist.github.com/typebrook/b0d2e7e67aa50298fdf8111ae7466b56
#
#
# This script host your gists as local Github repo
# It works under GNU with jq and curl, both are easy to get in most cases
#
# Use the following commands to manage your gists:
# 
# * update your gists list with Github API
# gist [update | u] 
# 
# * list your gists with format: [number] [url] [file_num] [comment_num] [short description]
# gist  
# 
# * clone gist repos which are not in local
# * pull master branch if a local repo is behind its remote
# gist [sync | s] 
#
# * Go to local gist repo
# . gist <number_of_gist_in_list> 
#
# * create a new gist with a file and description
# gist [create | c] <filename> "<description>"
#
# * show the detail of a gist
# gist [detail | d] <number_of_gist_in_list>
#
# * edit a gist description
# gist [edit | e] <number_of_gist_in_list>
#
# * delete a gist
# gist [delete | D] <number_of_gist_in_list>
#
# * clean removed gists in local
# gist [clean | C]

# * show this help message
# gist [help | h]

# define your environmemnts here
# TODO support auth prompt
# TODO error handling
# completion
#-------------------
github_api_token=$(cat $SETTING_DIR/tokens/github)
user=typebrook
folder=~/git/gist
#-------------------

github_api=https://api.github.com
auth_header="Authorization: token $github_api_token"
mkdir -p $folder
index=$folder/index
starred=$folder/starred

# Validate settings.
[ "$TRACE" ] && set -x

# Show the list of gist, but not updated time
# TODO show git status outdated
_show_list() {
    list_file=$index
    mark=""
    [[ "$1" == "--star" ]] && list_file=$starred && mark="s"

    cat $list_file |\
    while read line_num link file_url_array file_num extra description; do
        repo=$folder/$(echo $link | sed 's#.*/##')

        # if repo is not yet cloned, show green message "Sync Now"
        cd $repo 2>/dev/null || extra="\e[32m[Sync Now]\e[0m"
        # if there are some changes in git index or working directory, show blue message "working"
        [[ -n $(git status --short) ]] 2>/dev/null && extra="\e[36m[working]\e[0m" 
        # if there is a commit not yet push, show red message "ahead"
        [[ -n $(git cherry) ]] 2>/dev/null && extra="\e[31m[ahead]\e[0m" 

        echo -e $mark$line_num $link $file_num $extra $description
    done
}

# get the list of gists
# TODO support secret gist
_update() {
    list_file=$index
    route="users/$user/gists"
    [[ "$1" == "--star" ]] && list_file=$starred && route="gists/starred"

    curl -s -H "$auth_header" $github_api/$route |\
    jq '.[] | "\(.html_url) \([.files[] | .raw_url]) \(.files | keys | length) \(.comments) \(.description)"' |\
    tac | nl |\
    while read line_num link file_url_array file_num comment_num description; do
        blob_code=$(echo $file_url_array | jq -r '.[]' | sed -E 's#.*raw/(.*)/.*#\1#' | sort | cut -c -7 | paste -sd '-')
        echo $line_num $link $blob_code $file_num $comment_num $(echo $description | cut -c -65) | tr -d '"'
    done > $list_file && \
    _show_list $1
    (_sync_repos $1 > /dev/null 2>&1 &)
}

_starred() {
    return 0
}

_sync_repos() {
    list_file=$index
    [[ "$1" == "--star" ]] && list_file=$starred && route="gists/starred"

    # clone repos which are not in the local
    comm -13 <(find $folder -maxdepth 1 -type d | sed '1d; s#.*/##' | sort) \
             <(cat $list_file | cut -d' ' -f2 | sed 's#.*/##' | sort) |\
    xargs -I{} git clone git@github.com:{}.git $folder/{}

    # pull if remote repo has different blob objects
    cat $index | cut -d' ' -f2,3 |\
    while read url blob_code_remote; do
        repo=$folder/$(echo $url | sed 's#.*/##')
        blob_code_local=$(cd $repo && git ls-tree master | cut -d' ' -f3 | cut -c-7 | sort | paste -sd '-')

        cd $repo && \
        [[ $blob_code_local != $blob_code_remote ]] && \
        [[ $(git rev-parse origin/master) == $(git rev-parse master) ]] && \
        git pull
    done
    echo Everything is fine!
}

_gist_id() {
    list_file=$index
    row_num=$1
    [[ "$1" =~ ^s ]] && list_file=$starred && row_num=$(echo $1 | tr -d 's')
    cat $list_file | sed -n "$row_num"p | cut -d' ' -f2 | sed -E 's#.*/##'
}

_goto_gist() {
    gist_num=$(wc -l $index | cut -d' ' -f1)
    if [[ ! "$1" =~ ^s?[0-9]+$ ]] || (( $1 > $gist_num )); then
        _show_list | grep "$1" || echo Nothing Found
        return 0
    fi

    GIST_ID=$(_gist_id $1)
    echo This gist is at $folder/$GIST_ID
    echo You can use the following command to jump to this directory:
    echo -e "    \e[31m. gist $1\e[0m"
    echo 
    cd $folder/$GIST_ID && ls && tig --all 2> /dev/null
}

_delete_gist() {
    GIST_ID=$(_gist_id $1)
    curl -X DELETE -s -H "$auth_header" $github_api/gists/$GIST_ID && \
    _update
}

# remove repos which are not in user gists anymore
_clean_repos() {
    comm -23 <(find $folder -maxdepth 1 -type d | sed '1d; s#.*/##' | sort) \
             <(cat $index | cut -d' ' -f2 | sed 's#.*/##' | sort) |\
    while read dir; do
        mv $folder/$dir /tmp && echo move $folder/$dir to /tmp
    done
}

# TODO format with simple text
_show_detail() {
    GIST_ID=$(_gist_id $1)
    curl -s -H "$auth_header" $github_api/gists/$GIST_ID |\
    jq '{site: .html_url, description: .description, public: .public, API: .url, created_at: .created_at, updated_at: .updated_at, files: (.files | keys)}'

    curl -s -H "$auth_header" $github_api/gists/$GIST_ID/comments |\
    jq '.[] | {user: .user.login, created_at: .created_at, updated_at: .updated_at, body: .body}'
}

# create a new gist with files
_create_gist() {
    echo -n 'description: '
    read DESC

    echo $@ | tr " " "\n" |\
    while read file; do
        FILE=$(basename $file)
        jq --arg FILE "$FILE" '. as $content | { ($FILE): {content: $content} }' -Rs $file
    done |\
    jq --slurp --arg DESC "$DESC" '{
        public: true,
        files: add,
        description: ($DESC)
    }' |\
    curl -s -H "$auth_header" --data @- $github_api/gists > /dev/null && \
    _update
}

# update description of a gist
_edit_gist() {
    GIST_ID=$(_gist_id $1)

    jq -n --arg DESC "$2" '{ description: ($DESC) }' |\
    curl -X PATCH -H "$auth_header" --data @- $github_api/gists/$GIST_ID > /dev/null && \
    _update
}

_help_message() {
    sed -E -n ' /^$/ q; 8,$ s/^#//p' $0
}

case "$1" in
  "")
    _show_list
    ;;
  create | c)
    shift;
    _create_gist $@
    ;;
  edit | e)
    _edit_gist "$2" "$3"
    ;;
  update | u)
    _update "$2"
    ;;
  star | s)
    _show_list --star
    ;;
  sync | S)
    _sync_repos
    ;;
  detail | d)
    _show_detail "$2"
    ;;
  delete | D)
    _delete_gist "$2"
    ;;
  clean | C)
    _clean_repos
    ;;
  help | h)
    _help_message
    ;;
  *)
    _goto_gist "$1"
    ;;
esac