var package = {}

var fd = use('fd')
var toml = use('toml')
var os = use('os')

function get_path(name)
{
  return os.global_shop_path + '/packages/' + name
}

package.load_config = function(name)
{
  var config_path = get_path(name) + '/cell.toml'
  if (!fd.is_file(config_path))
    throw new Error(`${config_path} isn't a path`)

  return toml.decode(text(fd.slurp(config_path)))
}

package.save_config = function(name, config)
{
  var config_path = get_path(name) + '/cell.toml'
  fd.slurpwrite(config_path, utf8.encode(toml.encode(config)))
}

package.dependencies = function(name)
{
  return package.load_config(name).dependencies
}

package.find_alias = function(name, locator)
{
  var config = package.load_config(name)
  if (!config.dependencies) return null
  
  for (var alias in config.dependencies)
    if (config.dependencies[alias] == locator)
      return alias

  return null
}

package.alias_to_package = function(name, alias)
{
  var config = package.load_config(name)
  if (!config.dependencies) return null
  return config.dependencies[alias]
}

// alias is optional
package.add_dependency = function(name, locator, alias = locator)
{
  var config = package.load_config(name)
  if (!config.dependencies) config.dependencies = {}
  config.dependencies[alias] = locator
  package.save_config(name, config)
}

// locator can be a locator or alias
package.remove_dependency = function(name, locator)
{
  var config = package.load_config(name)
  if (!config.dependencies) return
  
  if (config.dependencies[locator])
    delete config.dependencies[locator]
  else {
    var alias = package.find_alias(name, locator)
    if (alias)
      delete config.dependencies[alias]
  }
  package.save_config(name, config)
}

package.find_package_dir = function(file)
{
  var absolute = fd.realpath(file)
  
  var dir = absolute
  if (fd.is_file(dir)) {
    var last_slash = dir.lastIndexOf('/')
    if (last_slash > 0) dir = dir.substring(0, last_slash)
  }
  
  while (dir && dir.length > 0) {
    var toml_path = dir + '/cell.toml'
    if (fd.is_file(toml_path)) {
      return dir
    }
    var last_slash = dir.lastIndexOf('/')
    if (last_slash <= 0) break
    dir = dir.substring(0, last_slash)
  }
  
  return null
}

// For a given package,
// checks for an alias in path, and returns
// { package, path }
// so package + path is the full path
// Returns null if no alias is found for the given path
package.split_alias = function(name, path)
{
  if (!path || path.length == 0) {
    return null
  }
  
  var parts = path.split('/')
  var first_part = parts[0]
  
  var config = package.load_config(name)
  if (config.dependencies && config.dependencies[first_part]) {
    var dep_locator = config.dependencies[first_part]
    var remaining_path = parts.slice(1).join('/')
    return { package: dep_locator, path: remaining_path }
  }
  
  return null
}

package.gather_dependencies = function(name)
{
  var all_deps = {}
  var visited = {}
  
  function gather_recursive(pkg_name) {
    if (visited[pkg_name]) return
    visited[pkg_name] = true
    
    var deps = package.dependencies(pkg_name)
    if (!deps) return
    
    for (var alias in deps) {
      var locator = deps[alias]
      if (!all_deps[locator]) {
        all_deps[locator] = true
        gather_recursive(locator)
      }
    }
  }
  
  gather_recursive(name)
  return array(all_deps)
}

package.list_files = function(pkg) {
  var dir = get_path(pkg)
  
  var files = []
  
  var walk = function(current_dir, current_prefix) {
    var list = fd.readdir(current_dir)
    if (!list) return
    
    for (var i = 0; i < list.length; i++) {
      var item = list[i]
      if (item == '.' || item == '..') continue
      if (item.startsWith('.')) continue 
      
      // Skip build directories in root

      var full_path = current_dir + "/" + item
      var rel_path = current_prefix ? current_prefix + "/" + item : item
      
      var st = fd.stat(full_path)
      if (st.isDirectory) {
        walk(full_path, rel_path)
      } else {
        files.push(rel_path)
      }
    }
  }
  
  if (fd.is_dir(dir)) {
    walk(dir, "")
  }
  return files
}

package.list_modules = function(name) {
  var files = package.list_files(name)
  var modules = []
  for (var i = 0; i < files.length; i++) {
    if (files[i].endsWith('.cm')) {
      modules.push(files[i].substring(0, files[i].length - 3))
    }
  }
  return modules
}

package.list_programs = function(name) {
  var files = package.list_files(name)
  var programs = []
  for (var i = 0; i < files.length; i++) {
    if (files[i].endsWith('.ce')) {
      programs.push(files[i].substring(0, files[i].length - 3))
    }
  }
  return programs
}

// Get flags from cell.toml for a package
// flag_type is 'CFLAGS' or 'LDFLAGS'
// target is optional (e.g., 'macos_arm64', 'playdate')
// Returns an array of flag strings
package.get_flags = function(name, flag_type, target) {
  var config = package.load_config(name)
  var flags = []
  
  // Base flags
  if (config.compilation && config.compilation[flag_type]) {
    var base = config.compilation[flag_type]
    flags = flags.concat(base.split(/\s+/).filter(function(f) { return f.length > 0 }))
  }
  
  // Target-specific flags
  if (target && config.compilation && config.compilation[target] && config.compilation[target][flag_type]) {
    var target_flags = config.compilation[target][flag_type]
    flags = flags.concat(target_flags.split(/\s+/).filter(function(f) { return f.length > 0 }))
  }
  
  return flags
}

// Get all C files for a package, handling target-specific variants
// Excludes main.c for dynamic builds (when exclude_main is true)
// Handles patterns like fd.c vs fd_playdate.c
package.get_c_files = function(name, target, exclude_main) {
  var toolchains = use('toolchains')
  var known_targets = array(toolchains)
  var files = package.list_files(name)
  
  // Group files by their base name (without target suffix)
  var groups = {} // base_key -> { generic: file, variants: { target: file } }
  
  for (var i = 0; i < files.length; i++) {
    var file = files[i]
    if (!file.endsWith('.c') && !file.endsWith('.cpp')) continue
    
    var ext = file.endsWith('.cpp') ? '.cpp' : '.c'
    var base = file.substring(0, file.length - ext.length)
    var dir = ''
    var name_part = base
    var slash = base.lastIndexOf('/')
    if (slash >= 0) {
      dir = base.substring(0, slash + 1)
      name_part = base.substring(slash + 1)
    }
    
    // Check for target suffix
    var is_variant = false
    var variant_target = null
    var generic_name = name_part
    
    for (var t = 0; t < known_targets.length; t++) {
      var suffix = '_' + known_targets[t]
      if (name_part.endsWith(suffix)) {
        is_variant = true
        variant_target = known_targets[t]
        generic_name = name_part.substring(0, name_part.length - suffix.length)
        break
      }
    }
    
    var group_key = dir + generic_name + ext
    if (!groups[group_key]) {
      groups[group_key] = { generic: null, variants: {} }
    }
    
    if (is_variant) {
      groups[group_key].variants[variant_target] = file
    } else {
      groups[group_key].generic = file
    }
  }
  
  // Select appropriate file from each group
  var result = []
  for (var key in groups) {
    var group = groups[key]
    var selected = null
    
    // Prefer target-specific variant if available
    if (target && group.variants[target]) {
      selected = group.variants[target]
    } else if (group.generic) {
      selected = group.generic
    }
    
    if (selected) {
      // Skip main.c if requested
      if (exclude_main) {
        var basename = selected
        var s = selected.lastIndexOf('/')
        if (s >= 0) basename = selected.substring(s + 1)
        if (basename == 'main.c' || basename.startsWith('main_')) continue
      }
      result.push(selected)
    }
  }
  
  return result
}

// Get the absolute path for a package
package.get_dir = function(name) {
  return get_path(name)
}

return package