require "mkmf"
require "mini_portile2"
require "yaml"

module Sqlite3
  module ExtConf
    ENV_ALLOWLIST = ["CC", "CFLAGS", "LDFLAGS", "LIBS", "CPPFLAGS", "LT_SYS_LIBRARY_PATH", "CPP"]

    class << self
      def configure
        configure_cross_compiler

        if system_libraries?
          message "Building sqlite3-ruby using system #{libname}.\n"
          configure_system_libraries
        else
          message "Building sqlite3-ruby using packaged sqlite3.\n"
          configure_packaged_libraries
        end

        configure_extension

        create_makefile('sqlite3/sqlite3_native')
      end

      def configure_cross_compiler
        RbConfig::CONFIG["CC"] = RbConfig::MAKEFILE_CONFIG["CC"] = ENV["CC"] if ENV["CC"]
        ENV["CC"] = RbConfig::CONFIG["CC"]
      end

      def system_libraries?
        sqlcipher? || enable_config("system-libraries")
      end

      def libname
        sqlcipher? ? "sqlcipher" : "sqlite3"
      end

      def sqlcipher?
        with_config("sqlcipher") ||
          with_config("sqlcipher-dir") ||
          with_config("sqlcipher-include") ||
          with_config("sqlcipher-lib")
      end

      def configure_system_libraries
        pkg_config(libname)
        append_cppflags("-DUSING_SQLCIPHER") if sqlcipher?
      end

      def configure_packaged_libraries
        minimal_recipe.tap do |recipe|
          recipe.configure_options += ["--enable-shared=no", "--enable-static=yes"]
          ENV.to_h.tap do |env|
            additional_cflags = [
              "-fPIC", # needed for linking the static library into a shared library
              "-O2", # see https://github.com/sparklemotion/sqlite3-ruby/issues/335 for some benchmarks
            ]
            env["CFLAGS"] = [env["CFLAGS"], additional_cflags].flatten.join(" ")
            recipe.configure_options += env.select { |k,v| ENV_ALLOWLIST.include?(k) }
                                           .map { |key, value| "#{key}=#{value.strip}" }
          end

          unless File.exist?(File.join(recipe.target, recipe.host, recipe.name, recipe.version))
            recipe.cook
          end
          recipe.activate

          ENV["PKG_CONFIG_ALLOW_SYSTEM_CFLAGS"] = "t" # on macos, pkg-config will not return --cflags without this
          pcfile = File.join(recipe.path, "lib", "pkgconfig", "sqlite3.pc")
          if pkg_config(pcfile)
            # see https://bugs.ruby-lang.org/issues/18490
            libs = xpopen(["pkg-config", "--libs", "--static", pcfile], err: [:child, :out], &:read)
            libs.split.each { |lib| append_ldflags(lib) } if $?.success?
          else
            abort("\nCould not configure the build properly. Please install either the `pkg-config` utility or the `pkg-config` rubygem.\n\n")
          end
        end
      end

      def configure_extension
        if Gem::Requirement.new("< 2.7").satisfied_by?(Gem::Version.new(RUBY_VERSION))
          append_cppflags("-DTAINTING_SUPPORT")
        end

        if find_header("sqlite3.h")
          # noop
        elsif sqlcipher? && find_header("sqlcipher/sqlite3.h")
          append_cppflags("-DUSING_SQLCIPHER_INC_SUBDIR")
        else
          abort_could_not_find("sqlite3.h")
        end

        abort_could_not_find(libname) unless find_library(libname, "sqlite3_libversion_number", "sqlite3.h")

        # Functions defined in 1.9 but not 1.8
        have_func('rb_proc_arity')

        # Functions defined in 2.1 but not 2.0
        have_func('rb_integer_pack')

        # These functions may not be defined
        have_func('sqlite3_initialize')
        have_func('sqlite3_backup_init')
        have_func('sqlite3_column_database_name')
        have_func('sqlite3_enable_load_extension')
        have_func('sqlite3_load_extension')

        unless have_func('sqlite3_open_v2') # https://www.sqlite.org/releaselog/3_5_0.html
          abort("\nPlease use a version of SQLite3 >= 3.5.0\n\n")
        end

        have_func('sqlite3_prepare_v2')
        have_type('sqlite3_int64', 'sqlite3.h')
        have_type('sqlite3_uint64', 'sqlite3.h')
      end

      def minimal_recipe
        MiniPortile.new(libname, sqlite3_config[:version]).tap do |recipe|
          recipe.files = sqlite3_config[:files]
          recipe.target = File.join(package_root_dir, "ports")
          recipe.patch_files = Dir[File.join(package_root_dir, "patches", "*.patch")].sort
        end
      end

      def package_root_dir
        File.expand_path(File.join(File.dirname(__FILE__), "..", ".."))
      end

      def sqlite3_config
        mini_portile_config[:sqlite3]
      end

      def mini_portile_config
        # TODO: once Ruby 2.7 is no longer supported, use symbolize_names: true
        YAML.load_file(File.join(package_root_dir, "dependencies.yml"))
      end

      def abort_could_not_find(missing)
        abort("\nCould not find #{missing}.\nPlease visit https://github.com/sparklemotion/sqlite3-ruby for installation instructions.\n\n")
      end

      def cross_build?
        enable_config("cross-build")
      end

      def download
        minimal_recipe.download
      end

      def print_help
        print(<<~TEXT)
          USAGE: ruby #{$PROGRAM_NAME} [options]

            Flags that are always valid:

                --disable-system-libraries
                    Use the packaged libraries, and ignore the system libraries.
                    (This is the default behavior.)

                --enable-system-libraries
                    Use system libraries instead of building and using the packaged libraries.

                --with-sqlcipher
                    Use libsqlcipher instead of libsqlite3.
                    (Implies `--enable-system-libraries`.)

                --help
                    Display this message.


            Flags only used when using system libraries:

                General (applying to all system libraries):

                    --with-opt-dir=DIRECTORY
                        Look for headers and libraries in DIRECTORY.

                    --with-opt-lib=DIRECTORY
                        Look for libraries in DIRECTORY.

                    --with-opt-include=DIRECTORY
                        Look for headers in DIRECTORY.

                Related to sqlcipher:

                    --with-sqlcipher-dir=DIRECTORY
                        Look for sqlcipher headers and library in DIRECTORY.
                        (Implies `--with-sqlcipher` and `--enable-system-libraries`.)

                    --with-sqlcipher-lib=DIRECTORY
                        Look for sqlcipher library in DIRECTORY.
                        (Implies `--with-sqlcipher` and `--enable-system-libraries`.)

                    --with-sqlcipher-include=DIRECTORY
                        Look for sqlcipher headers in DIRECTORY.
                        (Implies `--with-sqlcipher` and `--enable-system-libraries`.)


            Flags only used when building and using the packaged libraries:

                --enable-cross-build
                    Enable cross-build mode. (You probably do not want to set this manually.)


            Environment variables used for compiling the C extension:

                CC
                    Use this path to invoke the compiler instead of `RbConfig::CONFIG['CC']`


            Environment variables passed through to the compilation of packaged libraries:

                CC
                CPPFLAGS
                CFLAGS
                LDFLAGS
                LIBS
                LT_SYS_LIBRARY_PATH
                CPP

        TEXT
      end
    end
  end
end

if arg_config("--help")
  Sqlite3::ExtConf.print_help
  exit!(0)
end

if arg_config("--download-dependencies")
  Sqlite3::ExtConf.download
  exit!(0)
end

Sqlite3::ExtConf.configure
