#!/bin/bash

__contains() {
    local value item
    value="$1"
    shift

    for item in "$@"; do
        if [ "$item" = "$value" ]; then
            return 0
        fi
    done
    return 1
}

__prepend() {
    local char list out
    char="$1"
    shift

    out=''
    for item in "$@"; do
        out="$out ${char}${item}"
    done
    printf "%s" "$out"
}

_passman() {
    local cur prev base switches completions
    COMPREPLY=()
    cur="${COMP_WORDS[COMP_CWORD]}"
    prev="${COMP_WORDS[COMP_CWORD-1]}"
    base="get list info passwd help add del modify manage promote demote"
    switches="-u -e"
    completions=''

    if [ "$cur" = -* ]; then
        completions="$switches"
    elif __contains "manage" "${COMP_WORDS[@]}"; then
        case "$prev" in
            "manage" )
                completions="user pass"
                ;;
            "user"|"pass" )
                completions=$(passman list "$prev")
                ;;
            * )
                local preprev initial
                preprev="${COMP_WORDS[COMP_CWORD-2]}"
                if [ "$preprev" = "user" ] || [ "$preprev" = "pass" ]; then
                    initial=$(passman list group)
                    completions="$(__prepend "+" $initial)"
                    completions="$completions $(__prepend "-" $initial)"
                fi
                ;;
        esac
    else
        case "$prev" in
            "passman")
                completions="$base $switches"
                ;;
            "help" )
                if [ "${COMP_WORDS[1]}" = "help" ]; then
                    completions="$base"
                fi
                ;;
            "get"|"modify" )
                completions=$(passman list pass)
                ;;
            "list"|"info"|"add"|"del" )
                completions="user group pass"
                ;;
            "-u"|"promote"|"demote" )
                completions=$(passman list user)
                ;;
            "user"|"group"|"pass" )
                completions=$(passman list "$prev")
                ;;
        esac
    fi

    COMPREPLY=($(compgen -W "${completions}" -- "${cur}"))
    return 0
}
complete -F _passman passman