# $1, $2, ... - elements of the list
# $NLIST_NONSELECTABLE_ELEMENTS - array of indexes (1-based) that cannot be selected
# $REPLY is the output variable - contains index (1-based) or -1 when no selection
#
# Copy this file into /usr/share/zsh/site-functions/
# and add 'autoload n-list` to .zshrc
#
# This function outputs a list of elements that can be
# navigated with keyboard. Uses curses library

emulate -LR zsh

setopt typesetsilent extendedglob noshortloops

_nlist_has_terminfo=0

zmodload zsh/curses
zmodload zsh/terminfo 2>/dev/null && _nlist_has_terminfo=1

trap "REPLY=-2; reply=(); return" TERM INT QUIT
trap "_nlist_exit" EXIT

# Drawing and input
autoload n-list-draw n-list-input

# Cleanup before any exit
_nlist_exit() {
    setopt localoptions
    setopt extendedglob

    [[ "$REPLY" = -(#c0,1)[0-9]## ]] || REPLY="-1"
    zcurses 2>/dev/null delwin inner
    zcurses 2>/dev/null delwin main
    zcurses 2>/dev/null refresh
    zcurses end
    _nlist_alternate_screen 0
    _nlist_cursor_visibility 1
    unset _nlist_has_terminfo
}

# Outputs a message in the bottom of the screen
_nlist_status_msg() {
    # -1 for border, -1 for 0-based indexing
    zcurses move main $(( term_height - 1 - 1 )) 2
    zcurses clear main eol
    zcurses string main "$1"
    #status_msg_strlen is localized in caller
    status_msg_strlen=$#1
}

# Prefer tput, then module terminfo
_nlist_cursor_visibility() {
    if type tput 2>/dev/null 1>&2; then
        [ "$1" = "1" ] && { tput cvvis; tput cnorm }
        [ "$1" = "0" ] && tput civis
    elif [ "$_nlist_has_terminfo" = "1" ]; then
        [ "$1" = "1" ] && { [ -n $terminfo[cvvis] ] && echo -n $terminfo[cvvis];
                           [ -n $terminfo[cnorm] ] && echo -n $terminfo[cnorm] }
        [ "$1" = "0" ] && [ -n $terminfo[civis] ] && echo -n $terminfo[civis]
    fi 
}

# Reason for this function is that on some systems
# smcup and rmcup are not knowing why left empty
_nlist_alternate_screen() {
    [ "$_nlist_has_terminfo" -ne "1" ] && return
    [[ "$1" = "1" && -n "$terminfo[smcup]" ]] && return
    [[ "$1" = "0" && -n "$terminfo[rmcup]" ]] && return

    case "$TERM" in
        *rxvt*)
            [ "$1" = "1" ] && echo -n $'\x1b7\x1b[?47h'
            [ "$1" = "0" ] && echo -n $'\x1b[2J\x1b[?47l\x1b8'
            ;;
        *)
            [ "$1" = "1" ] && echo -n $'\x1b[?1049h'
            [ "$1" = "0" ] && echo -n $'\x1b[?1049l'
            # just to remember two other that work: $'\x1b7\x1b[r\x1b[?47h', $'\x1b[?47l\x1b8'
            ;;
    esac
}

_nlist_compute_user_vars_difference() {
        if [[ "${(t)NLIST_NONSELECTABLE_ELEMENTS}" != "array" &&
                "${(t)NLIST_NONSELECTABLE_ELEMENTS}" != "array-local" ]]
        then
            last_element_difference=0
            current_difference=0
        else
            last_element_difference=$#NLIST_NONSELECTABLE_ELEMENTS
            current_difference=0
            local idx
            for idx in "${(n)NLIST_NONSELECTABLE_ELEMENTS[@]}"; do
                [ "$idx" -le "$NLIST_CURRENT_IDX" ] && current_difference+=1 || break
            done
        fi
}

# List was processed, check if variables aren't off range
_nlist_verify_vars() {
    [ "$NLIST_CURRENT_IDX" -gt "$last_element" ] && NLIST_CURRENT_IDX="$last_element"
    [[ "$NLIST_CURRENT_IDX" -eq 0 && "$last_element" -ne 0 ]] && NLIST_CURRENT_IDX=1
    (( NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN=0+((NLIST_CURRENT_IDX-1)/page_height)*page_height+1 ))
}

# Compute the variables which are shown to the user
_nlist_setup_user_vars() {
    if [ "$1" = "1" ]; then
        # Basic values when there are no non-selectables
        NLIST_USER_CURRENT_IDX="$NLIST_CURRENT_IDX"
        NLIST_USER_LAST_ELEMENT="$last_element"
    else
        _nlist_compute_user_vars_difference
        NLIST_USER_CURRENT_IDX=$(( NLIST_CURRENT_IDX - current_difference ))
        NLIST_USER_LAST_ELEMENT=$(( last_element - last_element_difference ))
    fi
}

_nlist_colorify_disp_list() {
    local col=$'\x1b[00;34m' reset=$'\x1b[0m'
    [ -n "$NLIST_COLORING_COLOR" ] && col="$NLIST_COLORING_COLOR"
    [ -n "$NLIST_COLORING_END_COLOR" ] && reset="$NLIST_COLORING_END_COLOR"

    if [ "$NLIST_COLORING_MATCH_MULTIPLE" -eq 1 ]; then
        disp_list=( "${(@)disp_list//(#mi)$~NLIST_COLORING_PATTERN/$col${MATCH}$reset}" )
    else
        disp_list=( "${(@)disp_list/(#mi)$~NLIST_COLORING_PATTERN/$col${MATCH}$reset}" )
    fi
}

#
# Main code
#

# Check if there is proper input
if [ "$#" -lt 1 ]; then
    echo "Usage: n-list element_1 ..."
    return 1
fi

REPLY="-1"
typeset -ga reply
reply=()

integer term_height="$LINES"
integer term_width="$COLUMNS"
if [[ "$term_height" -lt 1 || "$term_width" -lt 1 ]]; then
    local stty_out=$( stty size )
    term_height="${stty_out% *}"
    term_width="${stty_out#* }"
fi
integer inner_height=term_height-3
integer inner_width=term_width-3
integer page_height=inner_height
integer page_width=inner_width

typeset -a list disp_list
integer last_element=$#
local action
local final_key
integer selection
integer last_element_difference=0
integer current_difference=0
local prev_search_buffer=""
integer prev_uniq_mode=0
integer prev_start_idx=-1

# Ability to remember the list between calls
if [[ -z "$NLIST_REMEMBER_STATE" || "$NLIST_REMEMBER_STATE" -eq 0 || "$NLIST_REMEMBER_STATE" -eq 2 ]]; then
    NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN=1
    NLIST_CURRENT_IDX=1
    NLIST_IS_SEARCH_MODE=0
    NLIST_SEARCH_BUFFER=""
    NLIST_TEXT_OFFSET=0
    NLIST_IS_UNIQ_MODE=0

    # Zero - because it isn't known, unless we
    # confirm that first element is selectable
    NLIST_USER_CURRENT_IDX=0
    [[ ${NLIST_NONSELECTABLE_ELEMENTS[(r)1]} != 1 ]] && NLIST_USER_CURRENT_IDX=1
    NLIST_USER_LAST_ELEMENT=$(( last_element - $#NLIST_NONSELECTABLE_ELEMENTS ))

    # 2 is init once, then remember
    [ "$NLIST_REMEMBER_STATE" -eq 2 ] && NLIST_REMEMBER_STATE=1
fi

if [ "$NLIST_START_IN_SEARCH_MODE" -eq 1 ]; then
    NLIST_START_IN_SEARCH_MODE=0
    NLIST_IS_SEARCH_MODE=1
fi

if [ -n "$NLIST_SET_SEARCH_TO" ]; then
    NLIST_SEARCH_BUFFER="$NLIST_SET_SEARCH_TO"
    NLIST_SET_SEARCH_TO=""
fi

if [ "$NLIST_START_IN_UNIQ_MODE" -eq 1 ]; then
    NLIST_START_IN_UNIQ_MODE=0
    NLIST_IS_UNIQ_MODE=1
fi

_nlist_alternate_screen 1
zcurses init
zcurses delwin main 2>/dev/null
zcurses delwin inner 2>/dev/null
zcurses addwin main "$term_height" "$term_width" 0 0
zcurses addwin inner "$inner_height" "$inner_width" 1 2
zcurses bg main white/black
zcurses bg inner white/black
if [ "$NLIST_IS_SEARCH_MODE" -ne 1 ]; then
    _nlist_cursor_visibility 0
fi

#
# Listening for input
#

local key keypad

# Clear input buffer
zcurses timeout main 0
zcurses input main key keypad
zcurses timeout main -1
key=""
keypad=""

list=( "$@" )
last_element="$#list"

while (( 1 )); do
    # Do searching (filtering with string)
    if [ -n "$NLIST_SEARCH_BUFFER" ]; then
        # Compute new list?
        if [[ "$NLIST_SEARCH_BUFFER" != "$prev_search_buffer" || "$NLIST_IS_UNIQ_MODE" -ne "$prev_uniq_mode" ]]; then
            prev_search_buffer="$NLIST_SEARCH_BUFFER"
            prev_uniq_mode="$NLIST_IS_UNIQ_MODE"
            # regenerating list -> regenerating disp_list
            prev_start_idx=-1

            # Take all elements, including duplicates and non-selectables
            typeset +U list
            list=( "$@" )

            # Remove non-selectable elements
            [ "$#NLIST_NONSELECTABLE_ELEMENTS" -gt 0 ] && for i in "${(nO)NLIST_NONSELECTABLE_ELEMENTS[@]}"; do
                list[$i]=()
            done

            # Remove duplicates
            [ "$NLIST_IS_UNIQ_MODE" -eq 1 ] && typeset -U list

            last_element="$#list"

            # Next do the filtering
            local search_buffer="${NLIST_SEARCH_BUFFER%% ##}"
            search_buffer="${search_buffer## ##}"
            search_buffer="${search_buffer//(#m)[][*?|#~^()><\\]/\\$MATCH}"
            local search_pattern=""
            local colsearch_pattern=""
            if [ -n "$search_buffer" ]; then
                # Patterns will be *foo*~^*bar* and foo|bar)
                search_pattern="${search_buffer// ##/*~^*}"
                colsearch_pattern="${search_buffer// ##/|}"

                list=( "${(@M)list:#(#i)*$~search_pattern*}" )
                last_element="$#list"
            fi

            # Called after processing list
            _nlist_verify_vars
        fi

        _nlist_setup_user_vars 1

        integer end_idx=$(( NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN + page_height - 1 ))
        [ "$end_idx" -gt "$last_element" ] && end_idx=last_element

        if [ "$prev_start_idx" -ne "$NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN" ]; then
            prev_start_idx="$NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN"
            disp_list=( "${(@)list[NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN, end_idx]}" )

            if [ -n "$colsearch_pattern" ]; then
                local red=$'\x1b[00;31m' reset=$'\x1b[00;00m'
                disp_list=( "${(@)disp_list//(#mi)($~colsearch_pattern)/$red${MATCH}$reset}" )
            fi

            # We have display list, lets replace newlines with "\n" when needed (1/2)
            [ "$NLIST_REPLACE_NEWLINES" -eq 1 ] && disp_list=( "${(@)disp_list//$'\n'/\\n}" )
        fi

        # Output colored list
        n-list-draw "$(( (NLIST_CURRENT_IDX-1) % page_height + 1 ))" \
            "$page_height" "$page_width" 0 0 "$NLIST_TEXT_OFFSET" inner \
            "$disp_list[@]"
    else
        # There is no search, but there was in previous loop
        # OR
        # Uniq mode was entered or left out
        # -> compute new list
        if [[ -n "$prev_search_buffer" || "$NLIST_IS_UNIQ_MODE" -ne "$prev_uniq_mode" ]]; then
            prev_search_buffer=""
            prev_uniq_mode="$NLIST_IS_UNIQ_MODE"
            # regenerating list -> regenerating disp_list
            prev_start_idx=-1

            # Take all elements, including duplicates and non-selectables
            typeset +U list
            list=( "$@" )

            # Remove non-selectable elements only when in uniq mode
            [ "$NLIST_IS_UNIQ_MODE" -eq 1 ] && [ "$#NLIST_NONSELECTABLE_ELEMENTS" -gt 0 ] &&
            for i in "${(nO)NLIST_NONSELECTABLE_ELEMENTS[@]}"; do
                list[$i]=()
            done

            # Remove duplicates when in uniq mode
            [ "$NLIST_IS_UNIQ_MODE" -eq 1 ] && typeset -U list

            last_element="$#list"
            # Called after processing list
            _nlist_verify_vars
        fi

        # "1" - shouldn't bother with non-selectables
        _nlist_setup_user_vars "$NLIST_IS_UNIQ_MODE"

        integer end_idx=$(( NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN + page_height - 1 ))
        [ "$end_idx" -gt "$last_element" ] && end_idx=last_element

        if [ "$prev_start_idx" -ne "$NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN" ]; then
            prev_start_idx="$NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN"
            disp_list=( "${(@)list[NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN, end_idx]}" )

            [ -n "$NLIST_COLORING_PATTERN" ] && _nlist_colorify_disp_list

            # We have display list, lets replace newlines with "\n" when needed (2/2)
            [ "$NLIST_REPLACE_NEWLINES" -eq 1 ] && disp_list=( "${(@)disp_list//$'\n'/\\n}" )
        fi

        # Output the list
        n-list-draw "$(( (NLIST_CURRENT_IDX-1) % page_height + 1 ))" \
            "$page_height" "$page_width" 0 0 "$NLIST_TEXT_OFFSET" inner \
            "$disp_list[@]"
    fi

    local status_msg_strlen
    if [ "$NLIST_IS_SEARCH_MODE" = "1" ]; then
        local _txt2=""
        [ "$NLIST_IS_UNIQ_MODE" -eq 1 ] && _txt2="[-UNIQ-] "
        _nlist_status_msg "${_txt2}Filtering with: ${NLIST_SEARCH_BUFFER// /+}"
    elif [[ ${NLIST_NONSELECTABLE_ELEMENTS[(r)$NLIST_CURRENT_IDX]} != $NLIST_CURRENT_IDX ||
            -n "$NLIST_SEARCH_BUFFER" || "$NLIST_IS_UNIQ_MODE" -eq 1 ]]; then
        local _txt="" _txt2=""
        [ -n "$NLIST_GREP_STRING" ] && _txt=" [$NLIST_GREP_STRING]"
        [ "$NLIST_IS_UNIQ_MODE" -eq 1 ] && _txt2="[-UNIQ-] "
        _nlist_status_msg "${_txt2}Current #$NLIST_USER_CURRENT_IDX (of #$NLIST_USER_LAST_ELEMENT entries)$_txt"
    else
        _nlist_status_msg ""
    fi

    zcurses border main
    zcurses refresh main inner
    zcurses move main $(( term_height - 1 - 1 )) $(( status_msg_strlen + 2 ))

    # Wait for input
    zcurses input main key keypad

    # Get the special (i.e. "keypad") key or regular key
    if [ -n "$key" ]; then
        final_key="$key" 
    elif [ -n "$keypad" ]; then
        final_key="$keypad"
    else
        _nlist_status_msg "Inproper input detected"
        zcurses refresh main inner
    fi

    n-list-input "$NLIST_CURRENT_IDX" "$NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN" \
                    "$page_height" "$page_width" "$last_element" "$NLIST_TEXT_OFFSET" \
                    "$final_key" "$NLIST_IS_SEARCH_MODE" "$NLIST_SEARCH_BUFFER" \
                    "$NLIST_IS_UNIQ_MODE"

    selection="$reply[1]"
    action="$reply[2]"
    NLIST_CURRENT_IDX="$reply[3]"
    NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN="$reply[4]"
    NLIST_TEXT_OFFSET="$reply[5]"
    NLIST_IS_SEARCH_MODE="$reply[6]"
    NLIST_SEARCH_BUFFER="$reply[7]"
    NLIST_IS_UNIQ_MODE="$reply[8]"

    if [ "$action" = "SELECT" ]; then
        REPLY="$selection"
        reply=( "$list[@]" )
        break
    elif [ "$action" = "QUIT" ]; then
        REPLY=-1
        reply=( "$list[@]" )
        break
    elif [ "$action" = "REDRAW" ]; then
        zcurses clear main redraw
        zcurses clear inner redraw
    fi
done

# vim: set filetype=zsh: