#!/usr/bin/env bash
#
# Author: Hsieh Chin Fan
# License: MIT
# https://gist.github.com/typebrook/b0d2e7e67aa50298fdf8111ae7466b56
#
#
# This script host your gists as local Github repo
# It works with jq and curl, which 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
# 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]

# define your environmemnts here
#-------------------
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

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

# Show the list of gist, but not updated time
_show_list() {
   cat $index | cut -d' ' -f1-2,4-
}

# get the list of gists
_update() {
    curl -s -H "$auth_header" $github_api/users/$user/gists |\
    jq '.[] | "\(.html_url) \(.updated_at) \(.files | keys | length) \(.comments) \(.description)"' |\
    tr -d '"' | tac | nl |\
    while read line_num link file_num comment_num description; do
        echo $line_num $link $file_num $comment_num $(echo $description | cut -c -80)
    done > $index && \
    _show_list
}

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# TODO pull if repo is outdated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

_gist_id() {
    cat $index | sed -n "$1"p | cut -d' ' -f2 | sed -r 's#.*/##'
}

_goto_gist() {
    gist_num=$(wc -l $index | cut -d' ' -f1)
    if [[ ! "$1" =~ [0-9]+ ]] || (( $1 > $gist_num )); then
        echo Not a valid gist number: $1
        echo Use the number in the first column instead:
        echo
        show_list
        return 0
    fi

    GIST_ID=$(_gist_id $1)
    echo This gist is at $folder/$GIST_ID
    cd $folder/$GIST_ID && 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) |\
    xargs -I{} rm -rf $folder/{}
}

_show_detail() {
    GIST_ID=$(_gist_id $1)
    curl -s -H "$auth_header" $github_api/gists/$GIST_ID |\
    jq '{site: .html_url, description: .description, 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
# TODO support folder of 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 $file
    done |\
    jq -s --arg DESC "$DESC" '{
        public: true,
        files: add,
        description: ($DESC)
    }' |\
    curl -s -H "$auth_header" --data @- $github_api/gists > /dev/null && \
    _update && _sync_repos
}

# 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
}

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