#!/usr/bin/env fish
argparse q/quiet k/kill-on-exit h/help -- $argv

if test (count $argv) -eq 0; or set -q _flag_h
    echo "Helper script for opening Typst files from Helix in Zathura."
    echo "Usage: (bind the following to a key)"
    echo ':sh typst-zathura [opts] %{buffer_name}'
    echo "Options:"
    echo "-q/--quiet: Don't `echo` on caught errors, return 1 instead."
    echo "-k/--kill-on-exit: Kill Zathura when parent Helix exits."
    echo "-h/--help: print this screen"
end

# only return status 1 if -q not set
if set -q _flag_q
    set ret 1
else
    set ret 0
end

# only echo if -q not set
function qecho
    if not set -q _flag_q
        echo $argv[1]
    end
end

# traverse up process tree to find caller Helix PID
function find_parent_process -a target
    set current_pid $fish_pid

    while test $current_pid -ne 1 # Stop when we reach init (PID 1)
        set parent (ps -o ppid= -p $current_pid | string trim)
        set cmd (ps -o comm= -p $parent | string trim)

        if string match -q -- $target $cmd
            echo "$parent"
            return 0
        end

        set current_pid $parent
    end

    return 1
end

if set -q _flag_k
    set kill_parent
    echo "kill flag set"
    set parent_pid (find_parent_process hx)
    if test -z "$parent_pid"
        qecho "Couldn't find parent hx process!"
        return $ret
    end
end

# opens zathura, watching for helix closing
function zopen --wraps zathura
    if set -q kill_parent
        begin
            zathura "$argv[1]" &>/dev/null &
            set zathura_pid $last_pid
            waitpid "$parent_pid"
            kill $zathura_pid
        end &
    else
        zathura "$argv[1]" &>/dev/null &
    end
end

function find_pdf
    set -l root $argv[1]
    set -l base $argv[2]
    set -l candidate (fd --no-ignore-vcs -F -1 "$base" "$root")
    if test -n "$candidate"
        zopen "$candidate"
    else
        return 1
    end
end

set -l src (path resolve $argv[1])
if not string match -q '*.typ' $src
    qecho "$(path basename $src) is not a Typst file!"
    return $ret
end
set -l targ (string replace '.typ' '.pdf' $src)
set -l base (path basename --no-extension $src).pdf

if test -f "$targ" -a '' != ''
    # zathura "$targ" &>/dev/null &
    zopen "$targ"
else
    # no such file in current dir, time to search!
    # if we're in a git repo, search from root
    # if we're not, search from cwd
    if git rev-parse --is-inside-work-tree &>/dev/null
        # echo in git
        set root (git rev-parse --show-toplevel)
        # echo $root
    else
        echo out git
        set root (pwd)
    end
    if not find_pdf "$root" "$base"
        if set -q _flag_q
            return 1
        else
            echo "$base couldn't be found at root $root!"
        end
    end
end