#!/bin/bash

stderr(){ echo "$@" >/dev/stderr; }
error(){ stderr "Error: $@"; }
fault(){ test -n "$1" && error $1; stderr "Exiting."; exit 1; }
cancel(){ stderr "Canceled."; exit 2; }
exe() { (set -x; "$@"); }
print_array(){ printf '%s\n' "$@"; }
trim_trailing_whitespace() { sed -e 's/[[:space:]]*$//'; }
trim_leading_whitespace() { sed -e 's/^[[:space:]]*//'; }
trim_whitespace() { trim_leading_whitespace | trim_trailing_whitespace; }
check_var(){
    local __missing=false
    local __vars="$@"
    for __var in ${__vars}; do
        if [[ -z "${!__var}" ]]; then
            error "${__var} variable is missing."
            __missing=true
        fi
    done
    if [[ ${__missing} == true ]]; then
        fault
    fi
}

check_num(){
    local var=$1
    check_var var
    if ! [[ ${!var} =~ ^[0-9]+$ ]] ; then
        fault "${var} is not a number: '${!var}'"
    fi
}

debug_var() {
    local var=$1
    check_var var
    stderr "## DEBUG: ${var}=${!var}"
}

debug_array() {
    local -n ary=$1
    echo "## DEBUG: Array '$1' contains:"
    for i in "${!ary[@]}"; do
        echo "## ${i} = ${ary[$i]}"
    done
}

ask() {
    ## Ask the user a question and set the given variable name with their answer
    local __prompt="${1}"; local __var="${2}"; local __default="${3}"
    read -e -p "${__prompt}"$'\x0a: ' -i "${__default}" ${__var}
    export ${__var}
}

ask_no_blank() {
    ## Ask the user a question and set the given variable name with their answer
    ## If the answer is blank, repeat the question.
    local __prompt="${1}"; local __var="${2}"; local __default="${3}"
    while true; do
        read -e -p "${__prompt}"$'\x0a: ' -i "${__default}" ${__var}
        export ${__var}
        [[ -z "${!__var}" ]] || break
    done
}

ask_echo() {
    ## Ask the user a question then print the non-blank answer to stdout
    (
        ask_no_blank "$1" ASK_ECHO_VARNAME >/dev/stderr
        echo "${ASK_ECHO_VARNAME}"
    )
}

require_input() {
    ## require_input {PROMPT} {VAR} {DEFAULT}
    ## Read variable, set default if blank, error if still blank
    test -z ${3} && dflt="" || dflt=" (${3})"
    read -e -p "$1$dflt: " $2
    eval $2=${!2:-${3}}
    test -v ${!2} && fault "$2 must not be blank."
}

make_var_name() {
    # Make an environment variable out of any string
    # Replaces all invalid characters with a single _
    echo "$@" | sed -e 's/  */_/g' -e 's/--*/_/g' -e 's/[^a-zA-Z0-9_]/_/g' -e 's/__*/_/g' -e 's/.*/\U&/' -e 's/__*$//' -e 's/^__*//'
}

confirm() {
    ## Confirm with the user.
    local default=$1; local prompt=$2; local question=${3:-". Proceed?"}
    check_var default prompt question
    if [[ $default == "y" || $default == "yes" || $default == "ok" ]]; then
        dflt="Y/n"
    else
        dflt="y/N"
    fi
    read -e -p "${prompt}${question} (${dflt}): " answer
    answer=${answer:-${default}}
    if [[ ${answer,,} == "y" || ${answer,,} == "yes" || ${answer,,} == "ok" ]]; then
        return 0
    else
        return 1
    fi
}
check_deps() {
    missing=""
    for var in "$@"; do
        echo -n "Looking for ${var} ... " >/dev/stderr
        if ! command -v "${var}" >/dev/null 2>&1; then
            echo "Missing! No ${var} found in PATH." >/dev/stderr
            missing="${missing} ${var}"
        else
            echo found $(which "${var}")
        fi
    done

    if [[ -n "${missing}" ]]; then fault "Missing dependencies: ${missing}"; fi
}
check_emacs_unsaved_files() {
    lock_files=$(find . -name ".#*")
    if [ ! -z "$lock_files" ]; then
        echo "Warning: You have unsaved files in Emacs. Please save all files before building."
        echo "Unsaved files:"
        echo "$lock_files"
        return 1
    fi
}