#!/bin/zsh -f

# Tmux has lots of options and sub-commands. It's very tedious to manually
# check if the actual command's idea of all this matches the completion
# function. So this is a helper script that automates checking the state of
# _tmux.
#
# You need to call it like this, with a running tmux server:
#
# zsh -f check-tmux-state <path-to-tmux-binary> <path-to-_tmux-function>
#
# The script will tell you the differences in available and supported
# sub-commands, command aliases, server options, session options and
# window-options.
#
# It also checks if options have moved from one scope to another. If this
# happens, then the option in question also appears in the "new/old" listings
# of the involved scopes. First fix the scope changes, then the "new/old" lists
# are accurate.

emulate zsh
setopt extended_glob null_glob no_octal_zeroes

if (( $#argv != 2 )); then
    printf 'usage: zsh -f check-tmux-state <tmux-binary> <_tmux-function>\n'
    exit 1
fi

printf ' -!- Checking status of _tmux completion function definition -!-\n'

autoload -Uz colors
colors

tmux=$1
func=$2

differences=none

# We'll source the _tmux file and call a bunch of its functions to gather
# information. For that, we need to put a few stubs into place so sourcing the
# file doesn't blow up in our face.

# We need to disable the new "local" keyword to make our data retrieval trick
# work:
disable -r local

function _arguments () { }
function _describe () { }
function local () { }

typeset -A rev

source $func
__tmux-server-options
__tmux-session-options
__tmux-window-options

# Subcommand helper functions are defined like "function _tmux-foo() {"
# in the _tmux function definition file.
typeset -a supported_commands
supported_commands=( $( grep '^_tmux-[^(]*() *{$' $func |
                        sed -e 's,^.*\<_tmux-,,' -e 's,(.*$,,' ) )

# Ask tmux for available commands:
typeset -a available_commands
available_commands=( $( $tmux list-commands | cut -f1 -d' ' ) )

# Ask tmux for available aliases:
typeset -A available_aliases
available_aliases=( $( $tmux list-commands |
                       grep '^[a-z-]* *(' |
                       sed -e 's,^\([a-z-]*\) *(\([a-z-]*\))\(.*\)$,\2 \1,' ) )

# Gather information about options:
typeset -a supported_session_options
supported_session_options=( ${"${tmux_session_options[@]}"%%:*} )
typeset -a available_session_options
available_session_options=( $( $tmux show-options -g | cut -f1 -d' ' ) )

typeset -a available_server_options
supported_server_options=( ${"${tmux_server_options[@]}"%%:*} )
typeset -a supported_server_options
available_server_options=( $( $tmux show-options -s -g | cut -f1 -d' ' ) )

typeset -a supported_window_options
supported_window_options=( ${"${tmux_window_options[@]}"%%:*} )
typeset -a available_window_options
available_window_options=( $( $tmux show-options -w -g | cut -f1 -d' ' ) )

typeset -a supported available

function find_new () {
    local i
    new=()
    for i in "${available[@]}"; do
        [[ -z ${supported[(r)$i]} ]] && new+=( $i )
    done
}

function find_old () {
    local i
    old=()
    for i in "${supported[@]}"; do
        [[ -z ${available[(r)$i]} ]] && old+=( $i )
    done
}

function compare_sets() {
    name=$1
    local -a old new
    new=()
    old=()
    find_old
    find_new
    if (( $#old > 0 )) || (( $#new > 0 )); then
        printf '\n%sDifferences with %s:%s\n' ${fg[yellow]} $name $reset_color
        differences=some
        if (( $#new > 0 )); then
            printf '%sNew:%s' ${fg[green]} $reset_color
            printf ' %s' "${new[@]}"
            printf '\n'
        fi
        if (( $#old > 0 )); then
            printf '%sOld:%s' ${fg[red]} $reset_color
            printf ' %s' "${old[@]}"
            printf '\n'
        fi
    fi
}

function find_changed_scope() {
    name=$1
    local -a changes
    local i av
    changes=()
    for i in "${supported[@]}"; do
        av=${available[(r)$i]}
        [[ -n $av ]] && changes+=( $av )
    done
    if (( $#changes > 0 )); then
        differences=some
        printf '\n%sDifferences with scope %s:%s\n' \
               ${fg[yellow]} $name $reset_color
        printf '%sChanged:%s' ${fg[green]} $reset_color
        printf ' %s' "${changes[@]}"
        printf '\n'
    fi
}

supported=( "${supported_session_options[@]}" )
available=( "${available_server_options[@]}" )
find_changed_scope 'session=>server'

supported=( "${supported_server_options[@]}" )
available=( "${available_session_options[@]}" )
find_changed_scope 'server=>session'

supported=( "${supported_window_options[@]}" )
available=( "${available_session_options[@]}" )
find_changed_scope 'window=>session'

supported=( "${supported_session_options[@]}" )
available=( "${available_window_options[@]}" )
find_changed_scope 'session=>window'

supported=( "${supported_window_options[@]}" )
available=( "${available_server_options[@]}" )
find_changed_scope 'window=>server'

supported=( "${supported_server_options[@]}" )
available=( "${available_window_options[@]}" )
find_changed_scope 'server=>window'

supported=( "${supported_commands[@]}" )
available=( "${available_commands[@]}" )
compare_sets commands

supported=( "${supported_session_options[@]}" )
available=( "${available_session_options[@]}" )
compare_sets session_options

supported=( "${supported_server_options[@]}" )
available=( "${available_server_options[@]}" )
compare_sets server_options

supported=( "${supported_window_options[@]}" )
available=( "${available_window_options[@]}" )
compare_sets window_options

typeset -a alias_messages
for i in "${(k)_tmux_aliasmap[@]}"; do
    su=${_tmux_aliasmap[$i]}
    av=${available_aliases[$i]}
    if [[ -z $av ]]; then
        alias_messages+=( "${fg[red]}Old alias${reset_color}: $i ($su)" )
    elif [[ $av != $su ]]; then
        alias_messages+=( "Changed alias $i: is ($av) was ($su)" )
    fi
done
for i in "${(k)available_aliases[@]}"; do
    su=${_tmux_aliasmap[$i]}
    av=${available_aliases[$i]}
    if [[ -z $su ]]; then
        alias_messages+=( "${fg[green]}New alias${reset_color}: $i ($av)" )
    fi
done
if (( $#alias_messages > 0 )); then
    differences=some
    printf '\n%sDifferences with %s:%s\n' ${fg[yellow]} "aliases" $reset_color
    for i in "${alias_messages[@]}"; do
        printf '%s\n' $i
    done
fi

if [[ $differences == none ]]; then
    printf '\n... _tmux seems to be up to date!\n'
else
    printf '\n'
fi
exit 0