package hook

import (
	"fmt"
	"os"
	"path/filepath"
)

// ZshCompletionScript replaces Cobra's generated zsh completion. Cobra's script
// spawns a subshell per candidate and passes every host through _describe,
// which takes tens of seconds for thousands of hosts. This script splits the
// candidates with parameter expansion only: entries with a description
// (subcommands, flags) go through _describe, plain hostnames through compadd.
//
// The file works both from fpath (autoloaded as _netssh) and when sourced.
const ZshCompletionScript = `#compdef netssh
compdef _netssh netssh

# netssh zsh completion — generated by netssh, do not edit.
_netssh() {
  local -a lines described plain
  local out directive=0 entry ret=1
  local -a nospace

  out=$(netssh __complete "${(@)words[2,CURRENT]}" 2>/dev/null) || return 1
  lines=("${(@f)out}")
  if [[ ${lines[-1]} == :<-> ]]; then
    directive=${lines[-1]#:}
    lines[-1]=()
  fi
  # Directive 1: error.
  (( directive & 1 )) && return 1
  lines=(${lines:#_activeHelp_*})
  lines=(${lines:#})
  # Directive 2: no trailing space.
  (( directive & 2 )) && nospace=(-S '')

  # Directive 8: the lines are file extensions to filter by.
  if (( directive & 8 )); then
    local -a globs
    for entry in $lines; do globs+=("*.${entry}"); done
    _files -g "(${(j:|:)globs})"
    return
  fi
  # Directive 16: complete directories only.
  if (( directive & 16 )); then
    _files -/
    return
  fi

  described=(${(M)lines:#*$'\t'*})
  plain=(${lines:#*$'\t'*})
  if (( $#described )); then
    local -a items
    for entry in $described; do
      items+=("${${entry%%$'\t'*}//:/\\:}:${entry#*$'\t'}")
    done
    _describe -t commands 'netssh command' items $nospace && ret=0
  fi
  if (( $#plain )); then
    # netssh already filtered the hosts, also by the name after an instance
    # prefix: "fsn1" offers "prod/fsn1-…". 'l:|=*' lets zsh accept text
    # before the typed word instead of discarding these matches.
    local -a group=(-J hosts)
    # Directive 32: keep the order supplied by netssh.
    (( directive & 32 )) && group=(-V hosts)
    compadd $group -X '%Bhosts%b' -M 'l:|=*' $nospace -- $plain && ret=0
  fi
  # Directive 4: no file completion as a fallback.
  if (( ! $#lines && ! (directive & 4) )); then
    _files && ret=0
  fi
  return ret
}

if [ "$funcstack[1]" = "_netssh" ]; then
  _netssh "$@"
fi
`

// ZshCompletionNote tells the user how zsh picks up a completion file in dir.
func ZshCompletionNote(dir string) string {
	dump := filepath.Join(zshDir(), ".zcompdump")
	return fmt.Sprintf(`zsh loads it from fpath. The netssh block in your .zshrc adds %s
(netssh hook install). Otherwise add this before compinit:
  fpath=(%s $fpath)
Then refresh the completion cache: rm -f %s* && exec zsh`, dir, dir, dump)
}

func zshDir() string {
	if dir := os.Getenv("ZDOTDIR"); dir != "" {
		return dir
	}
	return os.Getenv("HOME")
}

// ZshFuncDir is the user directory netssh installs zsh completion files into.
func ZshFuncDir() string {
	return filepath.Join(os.Getenv("HOME"), ".zfunc")
}