#!/usr/bin/env sh

# Licensed under ArArv2 license: https://files.ari-web.xyz/files/ArAr.ari-archer.LICENSE
# Description: manage, switch and template licenses

# DEPENDS ON:
#    general utilities: coreutils [head, awk, ...]
#    license picker: fzf (optional)
#    automatic config generation: git (optional)
#    colours: ncurses (optional) [tput]

set -e

VERSION='0.8'

# Init

[ -z "$HOME" ] && HOME="$(eval echo '~')"

depend() { command -v -- "$1" >/dev/null || (echo "FATAL: depend(): Dependency '$1' broken" 1>&2 && exit 11); }

# Colours (requires ncurses)

if [ "$LMGR_COLOURS" != 0 ]; then
    depend 'tput'

    RED=$(tput setaf 1)
    GREEN=$(tput setaf 2)
    YELLOW=$(tput setaf 3)
    BRIGHT=$(tput bold)
    RESET=$(tput sgr0)
fi

# Aliases

alias lless='less -NrIMJ --use-color --incsearch --line-num-width=2'
alias ffind='find -L'

# Constants

LICENSE_DIR="$HOME/.config/licenses"
LICENSE_SED='s/^@//'

# Utility functions

error() { printf " ${RED}*${RESET} %s\n" "$1" 1>&2; }
warn() { printf " ${YELLOW}*${RESET} %s\n" "$1" 1>&2; }
info() { printf " ${GREEN}*${RESET} %s\n" "$1"; }
einfo() { printf " ${BRIGHT}*${RESET} %s\n" "$1"; }

check_valid_license() {
    lic="$(echo "$1" | sed "$LICENSE_SED")"
    echo "$1" | grep -qi '^@' || (error "License '$lic' is not valid" && exit 9)
    [ ! -f "$LICENSE_DIR"/"$lic" ] && (error "License '$lic' does not exist" && exit 10)

    return 0
}

sed_escape() { echo "$1" | sed -e 's/[\/&]/\\&/g'; }

# Functions

list_licenses() { ffind "$LICENSE_DIR" -maxdepth 1 -type f -printf " ${BRIGHT}*${RESET} @%f\n"; }

usage() {
    echo " License manager v$VERSION"
    echo ' manage, switch and template licenses'
    echo ''
    echo " \$AUTHOR_NAME          -- '$AUTHOR_NAME'"
    echo " \$AUTHOR_EMAIL         -- '$AUTHOR_EMAIL'"
    echo " \$AUTHOR_WEBSITE       -- '$AUTHOR_WEBSITE'"
    echo " \$LICENSE_DIR          -- '$LICENSE_DIR'"
    echo ''
    echo " [ENV=VAL ...] $(basename "$0") <flag | @license>"
    echo ''
    echo '  -help --help     -h                     show usage'
    echo '  -list-licenses   -l                     list awailable licenses'
    echo '  -current-license -c                     show current active project license'
    echo '  -pick-license    -p                     pick a license in a FZF menu'
    echo '  -preview-license -P @license_name       preview a license template'
    echo '  -remove-license  -r                     remove all licenses from the current project'
    echo "  -search-license  -s '<query | patten>'  search for license"
    echo '  -template-help   -T                     print help for templating'
    echo '  -new-template    -t                     create a new license template'
    echo '  -delete-license  -R @license_name ...   delete a license from templates'
    echo '  -new-config      -C                     create a default config overwriting current one'
    echo '  -check-conflict  -k                     check if current licene(s) are conflicting'
    echo ''
    echo " LMGR_COLOURS=0|[1]                       turn colour on (1) or off (0)               [${LMGR_COLOURS:-1}]"
}

make_new_config() {
    mkdir -p "$HOME"/.config

    {
        echo '#!/usr/bin/env sh'
        echo "export AUTHOR_NAME='$(git config user.name || echo "${USER}")'"
        echo "export AUTHOR_EMAIL='$(git config user.email || echo "${USER}@gmail.com")'"
        echo "export AUTHOR_WEBSITE='https://example.com/'"
        echo "export LICENSE_DIR='$LICENSE_DIR'"
    } >"$HOME"/.config/license.conf
}

show_license() {
    depend 'head'

    l_name='LICENSE'
    [ -f UNLICENSE ] && l_name='UNLICENSE'

    if [ -f "$l_name" ]; then
        head -n1 "$l_name" | sed 's/^\s*//; s/\s*$//'
    else
        echo 'strong copyright (no license)'
    fi
}

check_license_conflict() {
    if [ -f ./LICENSE ] && [ -f ./UNLICENSE ]; then
        error 'Licensing conflict: UNLICENSE and LICENSE both found'

        printf '   Do you either (1) Remove LICENSE or (2) Remove UNLICENSE? [1/2] '
        read -r lr

        case "$lr" in
        1) rm LICENSE ;;
        2) rm UNLICENSE ;;
        *) error "'$lr' is not an option" && exit 1 ;;
        esac || (error 'Could not resolve licensing conflict' && exit 6)
    fi

}

get_license() {
    depend 'cp'
    check_valid_license "$1"

    check_license_conflict

    user_license="$(echo "$1" | sed "$LICENSE_SED")"

    if [ ! -f "$LICENSE_DIR"/"$user_license" ]; then
        error "No licence by the name of '$1'"
        list_licenses
        error 'Use of of the above'

        exit 5
    elif [ -f ./LICENSE ] || [ -f ./UNLICENSE ]; then
        info "Found license: $(show_license)"

        printf '   Switch licenses? [y/n] '
        read -r yn

        [ ! "$yn" = "y" ] && exit
    fi

    l_name='LICENSE'
    [ "$(head -n1 "$LICENSE_DIR"/"$user_license")" = 'UNLICENSE' ] && l_name='UNLICENSE'

    cp -fiL "$LICENSE_DIR"/"$user_license" "$l_name"

    sed -i "$l_name" \
        -e "s/{{PROJECT_NAME}}/$(sed_escape "$(basename "$PWD")")/g" \
        -e "s/{{CURRENT_YEAR}}/$(sed_escape "$(date '+%Y')")/g" \
        -e "s/{{AUTHOR_NAME}}/$(sed_escape "$AUTHOR_NAME")/g" \
        -e "s/{{AUTHOR_EMAIL}}/$(sed_escape "$AUTHOR_EMAIL")/g" \
        -e "s/{{AUTHOR_WEBSITE}}/$(sed_escape "$AUTHOR_WEBSITE")/g"

    check_license_conflict

    info "Current license now is set to $(show_license)"
}

license_picker() {
    depend 'awk'
    depend 'fzf'

    license="$(list_licenses |
        awk '{ print $2 }' |
        sed "$LICENSE_SED" |
        FZF_DEFAULT_OPTS='' fzf --layout=reverse --height=20 --no-mouse -i --preview "cat $LICENSE_DIR/{}" || echo '')"

    if [ -z "$license" ]; then
        license_picker
        return
    fi

    get_license "@$license"
}

search_license() {
    for lic in $(list_licenses | awk '{ print $2 }' | sed "$LICENSE_SED"); do
        if echo "$lic $(head -n8 "$LICENSE_DIR"/"$lic")" | grep -iq "$1"; then
            einfo "@$lic"
        fi
    done
}

remove_license() {
    rm -f UNLICENSE LICENSE 2>/dev/null || true
    info "Current license now is set to $(show_license)"
}

templating_help() {
    {
        echo 'Templating'
        echo ''
        echo 'To template a license you need to create a file named'
        echo "the same like you want to refer to your license, let's say \`hello\` in this example"
        echo "so now create a file called hello in '$LICENSE_DIR/hello'"
        echo ''
        echo 'Now you can make your license there, now onto templating'
        echo ''
        echo 'The templating "language" is pretty simple, all syntax goes in {{...}}'
        echo 'So the variables are:'
        echo '  * {{PROJECT_NAME}}      -- The current project name (basename of current directory)'
        echo '  * {{CURRENT_YEAR}}      -- The current year'
        echo "  * {{AUTHOR_NAME}}       -- The author's full name"
        echo "  * {{AUTHOR_EMAIL}}      -- The author's email"
        echo "  * {{AUTHOR_WEBSITE}}    -- The author's website"
        echo ''
        echo 'Example of a template: https://raw.githubusercontent.com/TruncatedDinosour/dotfiles-cleaned/gentoo/dotfiles/config/licenses/ArAr2'
    } | lless
}

new_template() {
    printf 'License name/alias (spaces will be removed) -- '
    read -r ln

    [ -z "$ln" ] && (
        error 'Cannot leave license name empty'
        exit 7
    )

    ln="$LICENSE_DIR/$(echo "$ln" | tr -d ' ' | head -c250)"

    if [ -f "$ln" ]; then
        printf 'This license already exists, do you want to overwrite it? [y/n] '
        read -r yn

        [ "$yn" != 'y' ] && exit
    fi

    editor="${EDITOR:-}"

    if [ -z "$editor" ]; then
        printf 'Editor to open file in -- '
        read -r editor
    fi

    [ -z "$editor" ] && (
        error 'Cannot leave editor empty'
        exit 8
    )

    depend "$(basename "$editor" | awk '{print $1}')"

    set -x
    $editor "$ln"
    set +x

    [ -f "$ln" ] && einfo "License '$(basename "$ln")' saved"
}

delete_license() {
    check_valid_license "$1"
    rm -vi "$LICENSE_DIR"/"$(echo "$1" | sed "$LICENSE_SED")"
}

new_config() {
    einfo "This will overwite your config, are you sure you want do do that?"
    printf '   [y/n] '
    read -r yn

    [ "$yn" != 'y' ] && exit

    make_new_config
    info 'New config made and saved'
}

main() {
    if [ -f "$HOME/.config/license.conf" ]; then
        # shellcheck disable=1091
        . "$HOME/.config/license.conf"
    else
        warn 'No configuration file found. Creating it.'
        make_new_config
        exit 4
    fi

    if [ ! -d "$LICENSE_DIR" ]; then
        # shellcheck disable=2088
        warn "'$LICENSE_DIR' does not exist. Creating it."
        mkdir -p "$LICENSE_DIR"
    fi

    [ -z "$1" ] && (
        usage
        exit 1
    )

    ffind "$LICENSE_DIR" -not -name . -not -path "$LICENSE_DIR" -prune -not -type f -exec rm -R {} +

    check_license_conflict
    case "$1" in
    -help | --help | -h) usage ;;
    -list-licenses | -l) list_licenses ;;
    -current-license | -c) einfo "$(show_license)" ;;
    -pick-license | -p) license_picker ;;
    -preview-license | -P)
        check_valid_license "$2"
        lless "$LICENSE_DIR"/"$(echo "$2" | sed "$LICENSE_SED")" 2>/dev/null || einfo "License $2 not found"
        ;;
    -remove-license | -r) remove_license ;;
    -search-license | -s) search_license "$2" ;;
    -template-help | -T) templating_help ;;
    -new-template | -t) new_template ;;
    -delete-license | -R)
        tmp_l=0

        for lic in "$@"; do
            if [ "$tmp_l" = 0 ]; then
                tmp_l=1
                continue
            fi

            delete_license "$lic"
        done
        ;;
    -new-config | -C) new_config ;;
    -check-conflict | -k) check_license_conflict ;;

    @*) check_valid_license "$1" && get_license "$1" ;;
    *) error "Flag $1 is not known." && usage && exit 2 ;;
    esac
}

main "$@"