// cell boot [--native] <program> - Pre-compile all module dependencies in parallel
//
// Discovers all transitive module dependencies for a program,
// checks which are not yet cached, and compiles uncached ones
// in parallel using worker actors composed via parallel() requestors.
//
// Also used as a child actor by engine.cm for auto-boot.

var shop = use('internal/shop')
var fd = use('fd')

var is_native = false
var target_prog = null
var target_pkg = null
var i = 0

// Child actor mode: receive message from engine.cm
var _child_mode = false
var run_boot = null

$receiver(function(msg) {
  _child_mode = true
  is_native = msg.native || false
  target_prog = msg.program
  target_pkg = msg.package
  run_boot()
})

// CLI mode: parse arguments
if (args && length(args) > 0) {
  for (i = 0; i < length(args); i = i + 1) {
    if (args[i] == '--native') {
      is_native = true
    } else if (args[i] == '--help' || args[i] == '-h') {
      log.console("Usage: cell boot [--native] <program>")
      log.console("")
      log.console("Pre-compile all module dependencies for a program.")
      log.console("Uncached modules are compiled in parallel.")
      $stop()
    } else if (!starts_with(args[i], '-')) {
      target_prog = args[i]
    }
  }
  if (!target_prog) {
    log.error("boot: no program specified")
    $stop()
  }
}

// Discover all transitive module dependencies for a file
function discover_deps(file_path) {
  var visited = {}
  var scripts = []
  var c_packages = {}

  function trace(fp) {
    if (visited[fp]) return
    visited[fp] = true

    var fi = shop.file_info(fp)
    var file_pkg = fi.package
    var idx = null
    var j = 0
    var imp = null
    var mod_path = null
    var rinfo = null

    // record this script (skip the root program itself)
    if (ends_with(fp, '.cm')) {
      scripts[] = {path: fp, package: file_pkg}
    }

    var _trace = function() {
      idx = shop.index_file(fp)
      if (!idx || !idx.imports) return

      j = 0
      while (j < length(idx.imports)) {
        imp = idx.imports[j]
        mod_path = imp.module_path
        rinfo = shop.resolve_import_info(mod_path, file_pkg)

        if (rinfo) {
          if (rinfo.type == 'script' && rinfo.resolved_path) {
            trace(rinfo.resolved_path)
          } else if (rinfo.type == 'native' && rinfo.package) {
            c_packages[rinfo.package] = true
          }
        }
        j = j + 1
      }
    } disruption {}
    _trace()
  }

  trace(file_path)
  return {scripts: scripts, c_packages: array(c_packages)}
}

// Filter out already-cached modules
function filter_uncached(deps) {
  var uncached = []
  var j = 0
  var s = null

  j = 0
  while (j < length(deps.scripts)) {
    s = deps.scripts[j]
    if (is_native) {
      if (!shop.is_native_cached(s.path, s.package)) {
        uncached[] = {type: 'native_script', path: s.path, package: s.package}
      }
    } else {
      if (!shop.is_cached(s.path)) {
        uncached[] = {type: 'script', path: s.path, package: s.package}
      }
    }
    j = j + 1
  }

  // C packages always included — build_dynamic handles its own caching
  j = 0
  while (j < length(deps.c_packages)) {
    if (deps.c_packages[j] != 'core') {
      uncached[] = {type: 'c_package', package: deps.c_packages[j]}
    }
    j = j + 1
  }

  return uncached
}

function item_name(item) {
  if (item.path) return item.path
  return item.package
}

// Create a requestor that spawns a compile_worker actor for one item
function make_compile_requestor(item) {
  var worker = null
  var name = item_name(item)
  return function(callback, value) {
    log.console('boot: spawning worker for ' + name)
    $start(function(event) {
      if (event.type == 'greet') {
        worker = event.actor
        send(event.actor, {
          type: item.type,
          path: item.path,
          package: item.package
        })
      }
      if (event.type == 'stop') {
        callback(name)
      }
      if (event.type == 'disrupt') {
        log.error('boot: worker failed for ' + name)
        callback(null, {message: 'compile failed: ' + name})
      }
    }, 'compile_worker')
    return function cancel(reason) {
      if (worker) $stop(worker)
    }
  }
}

run_boot = function() {
  var prog_path = null
  var prog_info = null
  var deps = null
  var uncached = null
  var requestors = null
  var p = null

  // Resolve the program path
  if (target_prog) {
    p = target_prog
    if (ends_with(p, '.ce')) p = text(p, 0, -3)
    prog_info = shop.resolve_program ? shop.resolve_program(p, target_pkg) : null
    if (prog_info) {
      prog_path = prog_info.path
      if (!target_pkg && prog_info.pkg) target_pkg = prog_info.pkg
    } else {
      prog_path = p + '.ce'
      if (!fd.is_file(prog_path)) {
        prog_path = null
      }
    }
  }

  if (!prog_path || !fd.is_file(prog_path)) {
    log.error('boot: could not find program: ' + text(target_prog || ''))
    $stop()
    return
  }

  // Discover all transitive deps
  deps = discover_deps(prog_path)
  uncached = filter_uncached(deps)

  if (length(uncached) == 0) {
    log.console('boot: all modules cached')
    $stop()
    return
  }

  // Compile uncached modules in parallel using worker actors
  log.console('boot: compiling ' + text(length(uncached)) + ' modules...')
  requestors = array(uncached, make_compile_requestor)
  parallel(requestors)(function(results, reason) {
    if (reason) {
      log.error('boot: ' + (reason.message || text(reason)))
    } else {
      log.console('boot: compiled ' + text(length(results)) + ' modules')
    }
    $stop()
  }, null)
}

// CLI mode: start immediately
if (!_child_mode && target_prog) {
  run_boot()
}