# Here we process the compiler's command line options and
# execute the relevant commands.
#
# Some commands are implemented in the `commands` directory,
# some in `tools`, some here, and some create a Compiler and
# manipulate it.
#
# Other commands create a `Compiler` and use it to build
# an executable.

require "json"
require "./command/*"
require "./tools/*"

class Crystal::Command
  USAGE = <<-USAGE
    Usage: crystal [command] [switches] [program file] [--] [arguments]

    Command:
        init                     generate a new project
        build                    build an executable
        clear_cache              clear the compiler cache
        docs                     generate documentation
        env                      print Crystal environment information
        eval                     eval code from args or standard input
        i/interactive            starts interactive Crystal
        play                     starts Crystal playground server
        run (default)            build and run program
        spec                     build and run specs (in spec directory)
        tool                     run a tool
        help, --help, -h         show this help
        version, --version, -v   show version

    Run a command followed by --help to see command specific information, ex:
        crystal <command> --help
    USAGE

  COMMANDS_USAGE = <<-USAGE
    Usage: crystal tool [tool] [switches] [program file] [--] [arguments]

    Tool:
        context                  show context for given location
        expand                   show macro expansion for given location
        format                   format project, directories and/or files
        hierarchy                show type hierarchy
        dependencies             show file dependency tree
        implementations          show implementations for given call in location
        unreachable              show methods that are never called
        types                    show type of main variables
        --help, -h               show this help
    USAGE

  def self.run(options = ARGV)
    new(options).run
  end

  private getter options
  @compiler : Compiler?

  def initialize(@options : Array(String))
    @color = ENV["TERM"]? != "dumb"
    @error_trace = false
    @progress_tracker = ProgressTracker.new
  end

  def run
    command = options.first?
    case
    when !command
      puts USAGE
      exit
    when command == "init"
      options.shift
      init
    when "build".starts_with?(command)
      options.shift
      build
      report_warnings
      exit 1 if warnings_fail_on_exit?
    when "play".starts_with?(command)
      options.shift
      {% if flag?(:without_playground) %}
        puts "Crystal was compiled without playground support"
        puts "Try the online code evaluation and sharing tool at https://play.crystal-lang.org"
        exit 1
      {% else %}
        playground
      {% end %}
    when "deps".starts_with?(command)
      STDERR.puts "Please use 'shards': 'crystal deps' has been removed"
      exit 1
    when "docs".starts_with?(command)
      options.shift
      docs
    when command == "env"
      options.shift
      env
    when command == "eval"
      options.shift
      eval
    when command.in?("i", "interactive")
      options.shift
      {% if flag?(:without_interpreter) %}
        STDERR.puts "Crystal was compiled without interpreter support"
        exit 1
      {% else %}
        repl
      {% end %}
    when command == "run"
      options.shift
      run_command(single_file: false)
    when "spec/".starts_with?(command)
      options.shift
      spec
    when "tool".starts_with?(command)
      options.shift
      tool
    when command == "clear_cache"
      options.shift
      clear_cache
    when "help".starts_with?(command), "--help" == command, "-h" == command
      puts USAGE
      exit
    when "version".starts_with?(command), "--version" == command, "-v" == command
      puts Crystal::Config.description
      exit
    when File.file?(command)
      run_command(single_file: true)
    else
      if command.ends_with?(".cr")
        error "file '#{command}' does not exist"
      else
        error "unknown command: #{command}"
      end
    end
  rescue ex : Crystal::CodeError
    report_warnings

    ex.color = @color
    ex.error_trace = @error_trace
    if @config.try(&.output_format) == "json"
      STDERR.puts ex.to_json
    else
      STDERR.puts ex
    end
    exit 1
  rescue ex : Crystal::Error
    report_warnings

    # This unwraps nested errors which could be caused by `require` which wraps
    # errors in order to trace the require path. The causes are listed similarly
    # to `#inspect_with_backtrace` but without the backtrace.
    while cause = ex.cause
      error ex.message, exit_code: nil
      ex = cause
    end

    error ex.message
  rescue ex : OptionParser::Exception
    error ex.message
  rescue ex
    report_warnings

    ex.inspect_with_backtrace STDERR
    error "you've found a bug in the Crystal compiler. Please open an issue, including source code that will allow us to reproduce the bug: https://github.com/crystal-lang/crystal/issues"
  end

  private def tool
    tool = options.first?
    case
    when !tool
      puts COMMANDS_USAGE
      exit
    when "context".starts_with?(tool)
      options.shift
      context
    when "format".starts_with?(tool)
      options.shift
      format
    when "expand".starts_with?(tool)
      options.shift
      expand
    when "hierarchy".starts_with?(tool)
      options.shift
      hierarchy
    when "dependencies".starts_with?(tool)
      options.shift
      dependencies
    when "implementations".starts_with?(tool)
      options.shift
      implementations
    when "types".starts_with?(tool)
      options.shift
      types
    when "unreachable".starts_with?(tool)
      options.shift
      unreachable
    when "--help" == tool, "-h" == tool
      puts COMMANDS_USAGE
      exit
    else
      error "unknown tool: #{tool}"
    end
  end

  private def init
    Init.run(options)
  end

  private def build
    config = create_compiler "build"
    config.compile
  end

  private def hierarchy
    config, result = compile_no_codegen "tool hierarchy", hierarchy: true, top_level: true
    @progress_tracker.stage("Tool (hierarchy)") do
      Crystal.print_hierarchy result.program, STDOUT, config.hierarchy_exp, config.output_format
    end
  end

  private def run_command(single_file = false)
    config = create_compiler "run", run: true, single_file: single_file
    if config.specified_output
      config.compile
      report_warnings
      exit 1 if warnings_fail_on_exit?
      return
    end

    output_filename = Crystal.temp_executable(config.output_filename)

    config.compile output_filename

    unless config.compiler.no_codegen?
      report_warnings
      exit 1 if warnings_fail_on_exit?

      execute output_filename, config.arguments, config.compiler
    end
  end

  private def types
    config, result = compile_no_codegen "tool types"
    @progress_tracker.stage("Tool (types)") do
      Crystal.print_types result.node
    end
  end

  private def compile_no_codegen(command, wants_doc = false, hierarchy = false, no_cleanup = false, cursor_command = false, top_level = false, path_filter = false, unreachable_command = false, allowed_formats = ["text", "json"])
    config = create_compiler command, no_codegen: true, hierarchy: hierarchy, cursor_command: cursor_command, path_filter: path_filter, unreachable_command: unreachable_command, allowed_formats: allowed_formats
    config.compiler.no_codegen = true
    config.compiler.no_cleanup = no_cleanup
    config.compiler.wants_doc = wants_doc
    result = top_level ? config.top_level_semantic : config.compile
    {config, result}
  end

  private def execute(output_filename, run_args, compiler, *, error_on_exit = false)
    time = @time && !@progress_tracker.stats?
    status, elapsed_time = @progress_tracker.stage("Execute") do
      begin
        elapsed = Time.measure do
          Process.run(output_filename, args: run_args, input: Process::Redirect::Inherit, output: Process::Redirect::Inherit, error: Process::Redirect::Inherit) do |process|
            {% unless flag?(:wasm32) %}
              # Ignore the signal so we don't exit the running process
              # (the running process can still handle this signal)
              Process.ignore_interrupts!
            {% end %}
          end
        end
        {$?, elapsed}
      ensure
        File.delete?(output_filename)

        # Delete related PDB generated by MSVC, if any exist
        {% if flag?(:msvc) %}
          unless compiler.debug.none?
            basename = output_filename.rchop(".exe")
            File.delete?("#{basename}.pdb")
          end
        {% end %}

        # Delete related dwarf generated by dsymutil, if any exist
        {% if flag?(:darwin) %}
          unless compiler.debug.none?
            File.delete?("#{output_filename}.dwarf")
          end
        {% end %}
      end
    end

    if time
      puts "Execute: #{elapsed_time}"
    end

    if status.exit_reason.normal? && !error_on_exit
      exit status.exit_code
    end

    if message = exit_message(status)
      STDERR.puts message
      STDERR.flush
    end

    exit 1
  end

  private def exit_message(status)
    case status.exit_reason
    when .aborted?
      if status.signal_exit?
        signal = status.exit_signal
        if signal.kill?
          "Program was killed"
        else
          "Program received and didn't handle signal #{signal} (#{signal.value})"
        end
      else
        "Program exited abnormally"
      end
    when .breakpoint?
      "Program hit a breakpoint and no debugger was attached"
    when .access_violation?, .bad_memory_access?
      # NOTE: this only happens with the empty prelude, because the stdlib
      # runtime catches those exceptions and then exits _normally_ with exit
      # code 11 or 1
      "Program exited because of an invalid memory access"
    when .bad_instruction?
      "Program exited because of an invalid instruction"
    when .float_exception?
      "Program exited because of a floating-point system exception"
    when .unknown?
      "Program exited abnormally, the cause is unknown"
    end
  end

  record CompilerConfig,
    compiler : Compiler,
    sources : Array(Compiler::Source),
    output_filename : String,
    emit_base_filename : String?,
    arguments : Array(String),
    specified_output : Bool,
    hierarchy_exp : String?,
    cursor_location : String?,
    output_format : String,
    combine_rpath : Bool,
    includes : Array(String),
    excludes : Array(String),
    verbose : Bool,
    check : Bool,
    tallies : Bool do
    def compile(output_filename = self.output_filename)
      compiler.emit_base_filename = emit_base_filename || output_filename.rchop(File.extname(output_filename))
      compiler.compile sources, output_filename, combine_rpath: combine_rpath
    end

    def top_level_semantic
      compiler.top_level_semantic sources
    end
  end

  private def create_compiler(command, no_codegen = false, run = false,
                              hierarchy = false, cursor_command = false,
                              single_file = false, dependencies = false,
                              path_filter = false, unreachable_command = false,
                              allowed_formats = ["text", "json"])
    compiler = new_compiler
    compiler.progress_tracker = @progress_tracker
    link_flags = [] of String
    filenames = [] of String
    has_stdin_filename = false
    opt_filenames = nil
    opt_arguments = nil
    opt_output_filename = nil
    specified_output = false
    hierarchy_exp = nil
    cursor_location = nil
    output_format = nil
    excludes = [] of String
    includes = [] of String
    verbose = false
    check = false
    tallies = false

    option_parser = parse_with_crystal_opts do |opts|
      opts.banner = "Usage: crystal #{command} [options] [programfile] [--] [arguments]\n\nOptions:"

      unless no_codegen
        unless run
          opts.on("--cross-compile", "cross-compile") do |cross_compile|
            compiler.cross_compile = true
          end
        end
        opts.on("-d", "--debug", "Add full symbolic debug info") do
          compiler.debug = Crystal::Debug::All
        end
        opts.on("--no-debug", "Skip any symbolic debug info") do
          compiler.debug = Crystal::Debug::None
        end
      end

      opts.on("-D FLAG", "--define FLAG", "Define a compile-time flag") do |flag|
        compiler.flags << flag
      end

      unless no_codegen
        valid_emit_values = Compiler::EmitTarget.names
        valid_emit_values.map!(&.gsub('_', '-').downcase)

        opts.on("--emit [#{valid_emit_values.join('|')}]", "Comma separated list of types of output for the compiler to emit") do |emit_values|
          compiler.emit_targets |= validate_emit_values(emit_values.split(',').map(&.strip))
        end
      end

      if hierarchy
        opts.on("-e NAME", "Filter types by NAME regex") do |exp|
          hierarchy_exp = exp
        end
      end

      if cursor_command
        opts.on("-c LOC", "--cursor LOC", "Cursor location with LOC as path/to/file.cr:line:column") do |cursor|
          cursor_location = cursor
        end
      end

      if dependencies
        opts.on("-i <path>", "--include <path>", "Include path") do |f|
          includes << f
        end

        opts.on("-e <path>", "--exclude <path>", "Exclude path (default: lib)") do |f|
          excludes << f
        end

        opts.on("--verbose", "Show skipped and filtered paths") do
          verbose = true
        end
      end

      opts.on("-f #{allowed_formats.join("|")}", "--format #{allowed_formats.join("|")}", "Output format: #{allowed_formats[0]} (default), #{allowed_formats[1..].join(", ")}") do |f|
        output_format = f
      end

      if unreachable_command
        opts.on("--tallies", "Print reachable methods and their call counts as well") do
          tallies = true
        end

        opts.on("--check", "Exits with error if there is any unreachable code") do |f|
          check = true
        end
      end

      opts.on("--error-trace", "Show full error trace") do
        compiler.show_error_trace = true
        @error_trace = true
      end

      opts.on("-h", "--help", "Show this message") do
        puts opts
        exit
      end

      if path_filter
        opts.on("-i <path>", "--include <path>", "Include path") do |f|
          includes << f
        end

        opts.on("-e <path>", "--exclude <path>", "Exclude path (default: lib)") do |f|
          excludes << f
        end
      end

      unless no_codegen
        opts.on("--ll", "Dump ll to Crystal's cache directory") do
          compiler.dump_ll = true
        end
        opts.on("--link-flags FLAGS", "Additional flags to pass to the linker") do |some_link_flags|
          link_flags << some_link_flags
        end
        target_specific_opts(opts, compiler)
        setup_compiler_warning_options(opts, compiler)
      end

      opts.on("--no-color", "Disable colored output") do
        @color = false
        compiler.color = false
      end

      unless no_codegen
        opts.on("--no-codegen", "Don't do code generation") do
          compiler.no_codegen = true
        end
        opts.on("-o ", "Output filename") do |an_output_filename|
          opt_output_filename = an_output_filename
          specified_output = true
        end
      end

      opts.on("--prelude ", "Use given file as prelude") do |prelude|
        compiler.prelude = prelude
      end

      unless no_codegen
        opts.on("--release", "Compile in release mode (-O3 --single-module)") do
          compiler.release!
        end
        opts.on("-O LEVEL", "Optimization mode: 0 (default), 1, 2, 3") do |level|
          optimization_mode = level.to_i?.try { |v| Compiler::OptimizationMode.from_value?(v) }
          compiler.optimization_mode = optimization_mode || raise Error.new("Invalid optimization mode: #{level}")
        end
      end

      opts.on("-s", "--stats", "Enable statistics output") do
        @progress_tracker.stats = true
      end

      opts.on("-p", "--progress", "Enable progress output") do
        @progress_tracker.progress = true
      end

      opts.on("-t", "--time", "Enable execution time output") do
        @time = true
      end

      unless no_codegen
        opts.on("--single-module", "Generate a single LLVM module") do
          compiler.single_module = true
        end
        opts.on("--threads NUM", "Maximum number of threads to use") do |n_threads|
          compiler.n_threads = n_threads.to_i? || raise Error.new("Invalid thread count: #{n_threads}")
        end
        unless run
          opts.on("--target TRIPLE", "Target triple") do |triple|
            compiler.codegen_target = Codegen::Target.new(triple)
          end
        end
        opts.on("--verbose", "Display executed commands") do
          compiler.verbose = true
        end
        opts.on("--static", "Link statically") do
          compiler.static = true
        end
      end

      opts.on("--stdin-filename ", "Source file name to be read from STDIN") do |stdin_filename|
        has_stdin_filename = true
        filenames << stdin_filename
      end

      if single_file
        opts.before_each do |arg|
          opts.stop if !arg.starts_with?('-') && arg.ends_with?(".cr")
          opts.stop if File.file?(arg)
        end
      end

      opts.unknown_args do |before, after|
        opt_filenames = before
        opt_arguments = after
      end
    end

    compiler.link_flags = link_flags.join(' ') unless link_flags.empty?

    output_filename = opt_output_filename
    filenames += opt_filenames.not_nil!
    arguments = opt_arguments.not_nil!

    if single_file && (files = filenames[1..-1]?)
      arguments = files + arguments
      filenames = [filenames[0]]
    end

    if filenames.size == 0 || (cursor_command && cursor_location.nil?)
      STDERR.puts option_parser
      exit 1
    end

    sources = [] of Compiler::Source
    if has_stdin_filename
      sources << Compiler::Source.new(filenames.shift, STDIN.gets_to_end)
    end
    sources.concat gather_sources(filenames)

    output_extension = compiler.cross_compile? ? compiler.codegen_target.object_extension : compiler.codegen_target.executable_extension
    if output_filename
      if File.extname(output_filename).empty?
        output_filename += output_extension
      end
    else
      first_filename = sources.first.filename
      output_filename = "#{::Path[first_filename].stem}#{output_extension}"

      # Check if we'll overwrite the main source file
      if !no_codegen && !run && first_filename == File.expand_path(output_filename)
        error "compilation will overwrite source file '#{Crystal.relative_filename(first_filename)}', either change its extension to '.cr' or specify an output file with '-o'"
      end
    end

    output_format ||= allowed_formats[0]
    unless output_format.in?(allowed_formats)
      error "You have input an invalid format: #{output_format}. Supported formats: #{allowed_formats.join(", ")}"
    end

    error "maximum number of threads cannot be lower than 1" if compiler.n_threads < 1

    if !no_codegen && !run && Dir.exists?(output_filename)
      error "can't use `#{output_filename}` as output filename because it's a directory"
    end

    if run
      emit_base_filename = ::Path[sources.first.filename].stem
    end

    combine_rpath = run && !no_codegen
    @config = CompilerConfig.new compiler, sources, output_filename, emit_base_filename,
      arguments, specified_output, hierarchy_exp, cursor_location, output_format.not_nil!,
      combine_rpath, includes, excludes, verbose, check, tallies
  end

  private def gather_sources(filenames)
    filenames.map do |filename|
      filename = File.expand_path(filename)
      Compiler::Source.new(filename, File.read(filename))
    end
  rescue exc : IO::Error
    error exc
  end

  private def setup_simple_compiler_options(compiler, opts)
    opts.on("-d", "--debug", "Add full symbolic debug info") do
      compiler.debug = Crystal::Debug::All
    end
    opts.on("--no-debug", "Skip any symbolic debug info") do
      compiler.debug = Crystal::Debug::None
    end
    opts.on("-D FLAG", "--define FLAG", "Define a compile-time flag") do |flag|
      compiler.flags << flag
    end
    opts.on("--error-trace", "Show full error trace") do
      @error_trace = true
      compiler.show_error_trace = true
    end
    opts.on("--release", "Compile in release mode (-O3 --single-module)") do
      compiler.release!
    end
    opts.on("-O LEVEL", "Optimization mode: 0 (default), 1, 2, 3") do |level|
      compiler.optimization_mode = Compiler::OptimizationMode.from_value?(level.to_i) || raise Error.new("Unknown optimization mode #{level}")
    end
    opts.on("-s", "--stats", "Enable statistics output") do
      compiler.progress_tracker.stats = true
    end
    opts.on("-p", "--progress", "Enable progress output") do
      compiler.progress_tracker.progress = true
    end
    opts.on("-t", "--time", "Enable execution time output") do
      @time = true
    end
    opts.on("-h", "--help", "Show this message") do
      puts opts
      exit
    end
    opts.on("--no-color", "Disable colored output") do
      @color = false
      compiler.color = false
    end
    target_specific_opts(opts, compiler)
    setup_compiler_warning_options(opts, compiler)
    opts.invalid_option { }
  end

  private def target_specific_opts(opts, compiler)
    opts.on("--mcpu CPU", "Target specific cpu type") do |cpu|
      if cpu == "native"
        compiler.mcpu = LLVM.host_cpu_name
      else
        compiler.mcpu = cpu
      end
    end
    opts.on("--mattr CPU", "Target specific features") do |features|
      compiler.mattr = features
    end
    opts.on("--mcmodel MODEL", "Target specific code model") do |mcmodel|
      compiler.mcmodel = case mcmodel
                         when "default" then LLVM::CodeModel::Default
                         when "small"   then LLVM::CodeModel::Small
                         when "kernel"  then LLVM::CodeModel::Kernel
                         when "medium"  then LLVM::CodeModel::Medium
                         when "large"   then LLVM::CodeModel::Large
                         else
                           error "--mcmodel should be one of: default, kernel, small, medium, large"
                           raise "unreachable"
                         end
    end
  end

  private def setup_compiler_warning_options(opts, compiler)
    opts.on("--warnings all|none", "Which warnings to detect. (default: all)") do |w|
      compiler.warnings.level = case w
                                when "all"
                                  Crystal::WarningLevel::All
                                when "none"
                                  Crystal::WarningLevel::None
                                else
                                  error "--warnings should be all, or none"
                                  raise "unreachable"
                                end
    end
    opts.on("--error-on-warnings", "Treat warnings as errors.") do |w|
      compiler.warnings.error_on_warnings = true
    end
    opts.on("--exclude-warnings <path>", "Exclude warnings from path (default: lib)") do |f|
      compiler.warnings.exclude_lib_path = false
      compiler.warnings.exclude_path(f)
    end

    compiler.warnings.exclude_lib_path = true
  end

  private def validate_emit_values(values)
    emit_targets = Compiler::EmitTarget::None
    values.each do |value|
      if target = Compiler::EmitTarget.parse?(value.gsub('-', '_'))
        emit_targets |= target
      else
        error "invalid emit value '#{value}'"
      end
    end
    emit_targets
  end

  private def error(msg, exit_code = 1)
    # This is for the case where the main command is wrong
    @color = false if ARGV.includes?("--no-color") || ENV["TERM"]? == "dumb"
    Crystal.error msg, @color, exit_code: exit_code
  end

  private def self.crystal_opts
    ENV["CRYSTAL_OPTS"]?.try { |opts| Process.parse_arguments(opts) }
  rescue ex
    raise Error.new("Failed to parse CRYSTAL_OPTS: #{ex.message}")
  end

  # Constructs an `OptionParser` from the given block and runs it twice, first
  # time with `CRYSTAL_OPTS`, second time with the given *options*.
  #
  # Only flags are accepted in the first run; positional arguments, invalid
  # options (where they might be treated as normal arguments), and `--` are all
  # disallowed. The option parser should not define any subcommands.
  def self.parse_with_crystal_opts(options, & : OptionParser ->)
    option_parser = OptionParser.new { |opts| yield opts }

    if crystal_opts = self.crystal_opts
      old_unknown_args = option_parser.@unknown_args
      old_invalid_option = option_parser.@invalid_option
      old_before_each = option_parser.@before_each

      option_parser.unknown_args { }
      option_parser.invalid_option { |opt| raise OptionParser::InvalidOption.new(opt) }
      option_parser.before_each do |opt|
        raise Error.new "CRYSTAL_OPTS may not contain --" if opt == "--"
      end

      option_parser.parse(crystal_opts)
      unless crystal_opts.empty?
        raise Error.new "CRYSTAL_OPTS may not contain positional arguments"
      end

      option_parser.unknown_args(&old_unknown_args) if old_unknown_args
      option_parser.invalid_option(&old_invalid_option)
      if old_before_each
        option_parser.before_each(&old_before_each)
      else
        option_parser.before_each { }
      end
    end

    option_parser.parse(options)
    option_parser
  end

  private def parse_with_crystal_opts(& : OptionParser ->)
    Command.parse_with_crystal_opts(@options) { |opts| yield opts }
  end

  private def new_compiler
    @compiler = Compiler.new
  end
end
