# Copy this file into /usr/share/zsh/site-functions/
# and add 'autoload n-history` to .zshrc
#
# This function allows to browse Z shell's history and use the
# entries
#
# Uses n-list

emulate -L zsh

setopt extendedglob
zmodload zsh/curses
zmodload zsh/parameter

local IFS="
"

# Variables to save list's state when switching views
# The views are: history and "most frequent history words"
local one_NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN
local one_NLIST_CURRENT_IDX
local one_NLIST_IS_SEARCH_MODE
local one_NLIST_SEARCH_BUFFER
local one_NLIST_TEXT_OFFSET
local one_NLIST_IS_UNIQ_MODE
local one_NLIST_IS_F_MODE
local one_NLIST_GREP_STRING
local one_NLIST_NONSELECTABLE_ELEMENTS
local one_NLIST_REMEMBER_STATE
local one_NLIST_ENABLED_EVENTS

local two_NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN
local two_NLIST_CURRENT_IDX
local two_NLIST_IS_SEARCH_MODE
local two_NLIST_SEARCH_BUFFER
local two_NLIST_TEXT_OFFSET
local two_NLIST_IS_UNIQ_MODE
local two_NLIST_IS_F_MODE
local two_NLIST_GREP_STRING
local two_NLIST_NONSELECTABLE_ELEMENTS
local two_NLIST_REMEMBER_STATE
local two_NLIST_ENABLED_EVENTS

local three_NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN
local three_NLIST_CURRENT_IDX
local three_NLIST_IS_SEARCH_MODE
local three_NLIST_SEARCH_BUFFER
local three_NLIST_TEXT_OFFSET
local three_NLIST_IS_UNIQ_MODE
local three_NLIST_IS_F_MODE
local three_NLIST_GREP_STRING
local three_NLIST_NONSELECTABLE_ELEMENTS
local three_NLIST_REMEMBER_STATE
local three_NLIST_ENABLED_EVENTS

# history view
integer active_view=0

# Lists are "0", "1", "2" - 1st, 2nd, 3rd
# Switching is done in cyclic manner
# i.e. 0 -> 1, 1 -> 2, 2 -> 0
_nhistory_switch_lists_states() {
    # First argument is current, newly selected list, i.e. $active_view
    # This implies that we are switching from previous view
   
    if [ "$1" = "0" ]; then
        # Switched to 1st list, save 3rd list's state
        three_NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN=$NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN
        three_NLIST_CURRENT_IDX=$NLIST_CURRENT_IDX
        three_NLIST_IS_SEARCH_MODE=$NLIST_IS_SEARCH_MODE
        three_NLIST_SEARCH_BUFFER=$NLIST_SEARCH_BUFFER
        three_NLIST_TEXT_OFFSET=$NLIST_TEXT_OFFSET
        three_NLIST_IS_UNIQ_MODE=$NLIST_IS_UNIQ_MODE
        three_NLIST_IS_F_MODE=$NLIST_IS_F_MODE
        three_NLIST_GREP_STRING=$NLIST_GREP_STRING
        three_NLIST_NONSELECTABLE_ELEMENTS=( ${NLIST_NONSELECTABLE_ELEMENTS[@]} )
        three_NLIST_REMEMBER_STATE=$NLIST_REMEMBER_STATE
        three_NLIST_ENABLED_EVENTS=( ${NLIST_ENABLED_EVENTS[@]} )

        # ..and restore 1st list's state
        NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN=$one_NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN
        NLIST_CURRENT_IDX=$one_NLIST_CURRENT_IDX
        NLIST_IS_SEARCH_MODE=$one_NLIST_IS_SEARCH_MODE
        NLIST_SEARCH_BUFFER=$one_NLIST_SEARCH_BUFFER
        NLIST_TEXT_OFFSET=$one_NLIST_TEXT_OFFSET
        NLIST_IS_UNIQ_MODE=$one_NLIST_IS_UNIQ_MODE
        NLIST_IS_F_MODE=$one_NLIST_IS_F_MODE
        NLIST_GREP_STRING=$one_NLIST_GREP_STRING
        NLIST_NONSELECTABLE_ELEMENTS=( ${one_NLIST_NONSELECTABLE_ELEMENTS[@]} )
        NLIST_REMEMBER_STATE=$one_NLIST_REMEMBER_STATE
        NLIST_ENABLED_EVENTS=( ${one_NLIST_ENABLED_EVENTS[@]} )
    elif [ "$1" = "1" ]; then
        # Switched to 2nd list, save 1st list's state
        one_NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN=$NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN
        one_NLIST_CURRENT_IDX=$NLIST_CURRENT_IDX
        one_NLIST_IS_SEARCH_MODE=$NLIST_IS_SEARCH_MODE
        one_NLIST_SEARCH_BUFFER=$NLIST_SEARCH_BUFFER
        one_NLIST_TEXT_OFFSET=$NLIST_TEXT_OFFSET
        one_NLIST_IS_UNIQ_MODE=$NLIST_IS_UNIQ_MODE
        one_NLIST_IS_F_MODE=$NLIST_IS_F_MODE
        one_NLIST_GREP_STRING=$NLIST_GREP_STRING
        one_NLIST_NONSELECTABLE_ELEMENTS=( ${NLIST_NONSELECTABLE_ELEMENTS[@]} )
        one_NLIST_REMEMBER_STATE=$NLIST_REMEMBER_STATE
        one_NLIST_ENABLED_EVENTS=( ${NLIST_ENABLED_EVENTS[@]} )

        # ..and restore 2nd list's state
        NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN=$two_NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN
        NLIST_CURRENT_IDX=$two_NLIST_CURRENT_IDX
        NLIST_IS_SEARCH_MODE=$two_NLIST_IS_SEARCH_MODE
        NLIST_SEARCH_BUFFER=$two_NLIST_SEARCH_BUFFER
        NLIST_TEXT_OFFSET=$two_NLIST_TEXT_OFFSET
        NLIST_IS_UNIQ_MODE=$two_NLIST_IS_UNIQ_MODE
        NLIST_IS_F_MODE=$two_NLIST_IS_F_MODE
        NLIST_GREP_STRING=$two_NLIST_GREP_STRING
        NLIST_NONSELECTABLE_ELEMENTS=( ${two_NLIST_NONSELECTABLE_ELEMENTS[@]} )
        NLIST_REMEMBER_STATE=$two_NLIST_REMEMBER_STATE
        NLIST_ENABLED_EVENTS=( ${two_NLIST_ENABLED_EVENTS[@]} )
    elif [ "$1" = "2" ]; then
        # Switched to 3rd list, save 2nd list's state
        two_NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN=$NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN
        two_NLIST_CURRENT_IDX=$NLIST_CURRENT_IDX
        two_NLIST_IS_SEARCH_MODE=$NLIST_IS_SEARCH_MODE
        two_NLIST_SEARCH_BUFFER=$NLIST_SEARCH_BUFFER
        two_NLIST_TEXT_OFFSET=$NLIST_TEXT_OFFSET
        two_NLIST_IS_UNIQ_MODE=$NLIST_IS_UNIQ_MODE
        two_NLIST_IS_F_MODE=$NLIST_IS_F_MODE
        two_NLIST_GREP_STRING=$NLIST_GREP_STRING
        two_NLIST_NONSELECTABLE_ELEMENTS=( ${NLIST_NONSELECTABLE_ELEMENTS[@]} )
        two_NLIST_REMEMBER_STATE=$NLIST_REMEMBER_STATE
        two_NLIST_ENABLED_EVENTS=( ${NLIST_ENABLED_EVENTS[@]} )

        # ..and restore 3rd list's state
        NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN=$three_NLIST_FROM_WHAT_IDX_LIST_IS_SHOWN
        NLIST_CURRENT_IDX=$three_NLIST_CURRENT_IDX
        NLIST_IS_SEARCH_MODE=$three_NLIST_IS_SEARCH_MODE
        NLIST_SEARCH_BUFFER=$three_NLIST_SEARCH_BUFFER
        NLIST_TEXT_OFFSET=$three_NLIST_TEXT_OFFSET
        NLIST_IS_UNIQ_MODE=$three_NLIST_IS_UNIQ_MODE
        NLIST_IS_F_MODE=$three_NLIST_IS_F_MODE
        NLIST_GREP_STRING=$three_NLIST_GREP_STRING
        NLIST_NONSELECTABLE_ELEMENTS=( ${three_NLIST_NONSELECTABLE_ELEMENTS[@]} )
        NLIST_REMEMBER_STATE=$three_NLIST_REMEMBER_STATE
        NLIST_ENABLED_EVENTS=( ${three_NLIST_ENABLED_EVENTS[@]} )
    fi
}

local most_frequent_db="$HOME/.config/znt/mostfrequent.db"
_nhistory_generate_most_frequent() {
    local title=$'\x1b[00;31m'"Most frequent history words:"$'\x1b[00;00m\0'

    typeset -A uniq
    for k in "${historywords[@]}"; do
        uniq[$k]=$(( ${uniq[$k]:-0} + 1 ))
    done
    vk=()
    for k v in ${(kv)uniq}; do
        vk+="$v"$'\t'"$k"
    done

    print -rl -- "$title" "${(On)vk[@]}" > "$most_frequent_db"
}

# Load configuration
unset NLIST_COLORING_PATTERN
[ -f ~/.config/znt/n-list.conf ] && builtin source ~/.config/znt/n-list.conf
[ -f ~/.config/znt/n-history.conf ] && builtin source ~/.config/znt/n-history.conf

local list
local selected
local private_history_db="$HOME/.config/znt/privhist.db"

local NLIST_GREP_STRING="$1"
# 2 is: init once, then remember
local NLIST_REMEMBER_STATE=2
two_NLIST_REMEMBER_STATE=2
three_NLIST_REMEMBER_STATE=2

# Only Private history has EDIT
local -a NLIST_ENABLED_EVENTS
NLIST_ENABLED_EVENTS=( "F1" "HELP" )
two_NLIST_ENABLED_EVENTS=( "F1" "EDIT" "HELP" )
three_NLIST_ENABLED_EVENTS=( "F1" "HELP" )

# All view should attempt to replace new lines with \n
local NLIST_REPLACE_NEWLINES="1"
two_NLIST_REPLACE_NEWLINES="1"
three_NLIST_REPLACE_NEWLINES="1"

# Only second and third view has non-selectable first entry
local -a NLIST_NONSELECTABLE_ELEMENTS
NLIST_NONSELECTABLE_ELEMENTS=( )
two_NLIST_NONSELECTABLE_ELEMENTS=( 1 )
three_NLIST_NONSELECTABLE_ELEMENTS=( 1 )

while (( 1 )); do

    #
    # View 1 - history
    #
    if [ "$active_view" = "0" ]; then
        list=( "$history[@]" )
        list=( "${(@M)list:#(#i)*$NLIST_GREP_STRING*}" )

        if [ "$#list" -eq 0 ]; then
            echo "No matching history entries"
            return 1
        fi

        n-list "${list[@]}"

        # Selection or quit?
        if [[ "$REPLY" = -(#c0,1)[0-9]## && ("$REPLY" -lt 0 || "$REPLY" -gt 0) ]]; then
            break
        fi

        # View change?
        if [ "$REPLY" = "F1" ]; then
            # Target view: 2
            active_view=1
            _nhistory_switch_lists_states "1"
        elif [ "$REPLY" = "HELP" ]; then
            n-help
        fi

    #
    # View 3 - most frequent words in history
    #
    elif [ "$active_view" = "2" ]; then
        local -a dbfile
        dbfile=( $most_frequent_db(Nm+1) )

        # Compute most frequent history words
        if [[ "${#NHISTORY_WORDS}" -eq "0" || "${#dbfile}" -ne "0" ]]; then
            # Read the list if it's there
            local -a list
            list=()
            [ -s "$most_frequent_db" ] && list=( ${(f)"$(<$most_frequent_db)"} )

            # Will wait for the data?
            local message=0
            if [[ "${#list}" -eq 0 ]]; then
                message=1
                _nlist_alternate_screen 1
                zcurses init
                zcurses delwin info 2>/dev/null
                zcurses addwin info "$term_height" "$term_width" 0 0
                zcurses bg info white/black
                zcurses string info "Computing most frequent history words..."$'\n'
                zcurses string info "(This is done once per day, from now on transparently)"$'\n'
                zcurses refresh info
                sleep 3
            fi

            # Start periodic list regeneration?
            if [[ "${#list}" -eq 0 || "${#dbfile}" -ne "0" ]]; then
                # Mark the file with current time, to prevent double
                # regeneration (on quick double change of view)
                print >> "$most_frequent_db"
                (_nhistory_generate_most_frequent &) &> /dev/null
            fi

            # Ensure we got the list, wait for it if needed
            while [[ "${#list}" -eq 0 ]]; do
                zcurses string info "."
                zcurses refresh info
                LANG=C sleep 0.5
                [ -s "$most_frequent_db" ] && list=( ${(f)"$(<$most_frequent_db)"} )
            done

            NHISTORY_WORDS=( "${list[@]}" )

            if [ "$message" -eq "1" ]; then
                zcurses delwin info 2>/dev/null
                zcurses refresh
                zcurses end
                _nlist_alternate_screen 0
            fi
        else
            # Reuse most frequent history words
            local -a list
            list=( "${NHISTORY_WORDS[@]}" )
        fi

        n-list "${list[@]}"

        if [ "$REPLY" = "F1" ]; then
            # Target view: 1
            active_view=0
            _nhistory_switch_lists_states "0"
        elif [[ "$REPLY" = -(#c0,1)[0-9]## && "$REPLY" -lt 0 ]]; then
            break
        elif [[ "$REPLY" = -(#c0,1)[0-9]## && "$REPLY" -gt 0 ]]; then
            local word="${reply[REPLY]#(#s) #[0-9]##$'\t'}"
            one_NLIST_SEARCH_BUFFER="$word"
            one_NLIST_SEARCH_BUFFER="${one_NLIST_SEARCH_BUFFER## ##}"

            # Target view: 1
            active_view=0
            _nhistory_switch_lists_states "0"
        elif [ "$REPLY" = "HELP" ]; then
            n-help
        fi

    #
    # View 2 - private history
    #
    elif [ "$active_view" = "1" ]; then
        if [ -s "$private_history_db" ]; then
            local title=$'\x1b[00;32m'"Private history:"$'\x1b[00;00m\0'
            () { fc -Rap "$private_history_db" 20000 0; list=( "$title" ${history[@]} ) }
        else
            list=( "Private history - history entries selected via this tool will be put here" )
        fi

        n-list "${list[@]}"

        # Selection or quit?
        if [[ "$REPLY" = -(#c0,1)[0-9]## && ("$REPLY" -lt 0 || "$REPLY" -gt 0) ]]; then
            break
        fi

        # View change?
        if [ "$REPLY" = "F1" ]; then
            # Target view: 3
            active_view=2
            _nhistory_switch_lists_states "2"
        # Edit of the history?
        elif [ "$REPLY" = "EDIT" ]; then
            "${EDITOR:-vim}" "$private_history_db"
        elif [ "$REPLY" = "HELP" ]; then
            n-help
        fi
    fi
done

if [ "$REPLY" -gt 0 ]; then
    selected="$reply[REPLY]"

    # Append to private history
    if [[ "$active_view" = "0" ]]; then
        local newline=$'\n'
        local selected_ph="${selected//$newline/\\$newline}"
        print -r -- "$selected_ph" >> "$private_history_db"
    fi

    # TMUX?
    if [[ "$ZNT_TMUX_MODE" = "1" ]]; then
        tmux send -t "$ZNT_TMUX_ORIGIN_SESSION:$ZNT_TMUX_ORIGIN_WINDOW.$ZNT_TMUX_ORIGIN_PANE" "$selected"
        tmux kill-window
        return 0
    # ZLE?
    elif [ "${(t)CURSOR}" = "integer-local-special" ]; then
        zle .redisplay
        zle .kill-buffer
        LBUFFER+="$selected"
    else
        print -zr -- "$selected"
    fi
else
    # TMUX?
    if [[ "$ZNT_TMUX_MODE" = "1" ]]; then
        tmux kill-window
    # ZLE?
    elif [[ "${(t)CURSOR}" = "integer-local-special" ]]; then
        zle redisplay
    fi
fi

return 0

# vim: set filetype=zsh: