#!/usr/bin/env nu
# Extract the complete import table and generate explicit unsupported host modules.
def main [binary: path, output: path] {
  mkdir $output
  let wat = (^wasm-tools print $binary)
  $wat | save --force ($output | path join git.wat)
  let types = ($wat | lines | parse -r '^  \(type \(;(?P<id>\d+);\) \(func(?P<sig>.*)\)\)$')
  let imports = ($wat | lines | parse -r '^  \(import "(?P<module>[^"]+)" "(?P<name>[^"]+)" \(func .*\(type (?P<id>\d+)\).*\)\)$' | each {|i|
    let sig = ($types | where id == $i.id | first | get sig)
    {module: $i.module, name: $i.name, signature: ($sig | str trim)}
  })
  $imports | to json | save --force ($output | path join imports.json)
  for module in ($imports | get module | uniq | where {|m| $m | str starts-with 'host_' }) {
    let functions = ($imports | where module == $module | each {|i|
      let result = ($i.signature | parse -r '\(result (?P<ty>\w+)\)' | get ty | first)
      let value = if $i.name in ['fd_mode' 'path_mode'] { '420' } else if $i.name =~ '(size|blocks)$' { '-1' } else if $i.name in ['fd_getfd' 'fd_setfd' 'set_open_mode'] { '0' } else { '52' }
      '  (func (export "' + $i.name + '") ' + $i.signature + ' ' + $result + '.const ' + $value + ')'
    } | str join (char nl))
    let file = ($output | path join $'($module).wat')
    ('(module' + (char nl) + $functions + (char nl) + ')') | save --force $file
    ^wasm-tools parse $file -o ($output | path join $'($module).wasm')
  }
}