#!/usr/bin/env bash

# In case the system uses a non-POSIX shell, like fish or nushell,
# we want to ensure run also our forked processes in a bash environment.
SHELL="bash"

# === Change keybinds or add more here ===

declare -a INDEXES=(
    "nixpkgs ctrl-n"
    "home-manager ctrl-h"

    # you can add any indexes combination here,
    # like `nixpkgs,nixos`

    "all ctrl-a"
)

SEARCH_SNIPPET_KEY="ctrl-w"
OPEN_SOURCE_KEY="ctrl-s"
OPEN_HOMEPAGE_KEY="ctrl-o"
NIX_SHELL_KEY="ctrl-i"
PRINT_PREVIEW_KEY="ctrl-p"

OPENER="xdg-open"

if [[ "$(uname)" == 'Darwin' ]]; then
    SEARCH_SNIPPET_KEY="alt-w"
    OPEN_SOURCE_KEY="alt-s"
    OPEN_HOMEPAGE_KEY="alt-o"
    NIX_SHELL_KEY="alt-i"
    PRINT_PREVIEW_KEY="alt-p"

    OPENER="open"
fi

# ========================================

# for debug / development
CMD="${NIX_SEARCH_TV:-nix-search-tv}"

# bind_index binds the given $key to the given $index
bind_index() {
    local key="$1"
    local index="$2"

    local prompt=""
    local indexes_flag=""
    if [[ -n "$index" && "$index" != "all" ]]; then
        indexes_flag="--indexes $index"
        prompt=$index
    fi

    local preview="$CMD preview $indexes_flag"
    local print="$CMD print $indexes_flag"

    echo "$key:change-prompt($prompt> )+change-preview($preview {})+reload($print)"
}

STATE_FILE="/tmp/nix-search-tv-fzf"

# save_state saves the currently displayed index
# to the $STATE_FILE. This file serves as an external script state
# for communication between "print" and "preview" commands
save_state() {
    local index="$1"

    local indexes_flag=""
    if [[ -n "$index" && "$index" != "all" ]]; then
        indexes_flag="--indexes $index"
    fi

    echo "execute(echo $indexes_flag > $STATE_FILE)"
}

HEADER="$OPEN_HOMEPAGE_KEY - open homepage
$OPEN_SOURCE_KEY - open source
$SEARCH_SNIPPET_KEY - search github for snippets
$NIX_SHELL_KEY - nix-shell
$PRINT_PREVIEW_KEY - print preview
"

FZF_BINDS=""
for e in "${INDEXES[@]}"; do
    index=$(echo "$e" | awk '{ print $1 }')
    keybind=$(echo "$e" | awk '{ print $2 }')

    fzf_bind=$(bind_index "$keybind" "$index")
    fzf_save_state=$(save_state "$index")
    FZF_BINDS="$FZF_BINDS --bind '$fzf_bind+$fzf_save_state'"

    newline=$'\n'
    HEADER="$HEADER$keybind - $index$newline"
done

# reset the state
echo "" >/tmp/nix-search-tv-fzf

SEARCH_SNIPPET_CMD=$'echo "{}"'
# fzf surrounds the matched package with ', trim them
SEARCH_SNIPPET_CMD="$SEARCH_SNIPPET_CMD | tr -d \"\'\" "
# if it's multi-index search, then we need to remote the prefix
SEARCH_SNIPPET_CMD="$SEARCH_SNIPPET_CMD | awk \'{ if (\$2) { print \$2 } else print \$1 }\' "
SEARCH_SNIPPET_CMD="$SEARCH_SNIPPET_CMD | xargs printf \"https://github.com/search?type=code&q=lang:nix+%s\" \$1 "

NIX_SHELL_CMD='nix-shell --run $SHELL -p $(echo "{}" | sed "s:nixpkgs/::g"'
NIX_SHELL_CMD="$NIX_SHELL_CMD | tr -d \"\'\")"

PREVIEW_WINDOW="wrap"
[ "$(tput cols)" -lt 90 ] && PREVIEW_WINDOW="$PREVIEW_WINDOW,up"

eval "$CMD print | fzf \
    --preview '$CMD preview \$(cat $STATE_FILE) {}' \
    --bind '$OPEN_SOURCE_KEY:execute($CMD source \$(cat $STATE_FILE) {} | xargs $OPENER)' \
    --bind '$OPEN_HOMEPAGE_KEY:execute($CMD homepage \$(cat $STATE_FILE) {} | xargs $OPENER)' \
    --bind $'$SEARCH_SNIPPET_KEY:execute($SEARCH_SNIPPET_CMD | xargs $OPENER)' \
    --bind $'$NIX_SHELL_KEY:become($NIX_SHELL_CMD)' \
    --bind $'$PRINT_PREVIEW_KEY:become($CMD preview \$(cat $STATE_FILE) {})' \
    --layout reverse \
    --scheme history \
    --preview-window='$PREVIEW_WINDOW' \
    --header '$HEADER' \
    --header-first \
    --header-border \
    --header-label \"Help\" \
    $FZF_BINDS
"