-module(glenv).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([load/2]).
-export_type([type/0, env_error/0]).

-if(?OTP_RELEASE >= 27).
-define(MODULEDOC(Str), -moduledoc(Str)).
-define(DOC(Str), -doc(Str)).
-else.
-define(MODULEDOC(Str), -compile([])).
-define(DOC(Str), -compile([])).
-endif.

?MODULEDOC(
    " glenv is a library for type-sfe environment variable access.\n"
    "\n"
).

-type type() :: bool | float | int | string.

-type env_error() :: {missing_key_error, binary()} |
    {invalid_env_value_error, binary(), type()} |
    {definition_mismatch_error, list(gleam@dynamic@decode:decode_error())}.

-file("src/glenv.gleam", 113).
-spec do_parse({binary(), type()}, binary()) -> {ok,
        {binary(), gleam@dynamic:dynamic_()}} |
    {error, env_error()}.
do_parse(Definition, Value) ->
    case Definition of
        {Key, bool} ->
            case glenv@internal@parse:bool(Key, Value) of
                {ok, Resolution} ->
                    {ok, Resolution};

                {error, _} ->
                    {error, {invalid_env_value_error, Key, bool}}
            end;

        {Key@1, float} ->
            case glenv@internal@parse:float(Key@1, Value) of
                {ok, Resolution@1} ->
                    {ok, Resolution@1};

                {error, _} ->
                    {error, {invalid_env_value_error, Key@1, float}}
            end;

        {Key@2, int} ->
            case glenv@internal@parse:int(Key@2, Value) of
                {ok, Resolution@2} ->
                    {ok, Resolution@2};

                {error, _} ->
                    {error, {invalid_env_value_error, Key@2, int}}
            end;

        {Key@3, string} ->
            case glenv@internal@parse:string(Key@3, Value) of
                {ok, Resolution@3} ->
                    {ok, Resolution@3};

                {error, _} ->
                    {error, {invalid_env_value_error, Key@3, string}}
            end
    end.

-file("src/glenv.gleam", 100).
-spec parse(list({binary(), type()})) -> {ok,
        list({binary(), gleam@dynamic:dynamic_()})} |
    {error, env_error()}.
parse(Definitions) ->
    Env = envoy_ffi:all(),
    gleam@list:try_map(
        Definitions,
        fun(Definition) ->
            Normalized_definition = {string:uppercase(
                    erlang:element(1, Definition)
                ),
                erlang:element(2, Definition)},
            case gleam_stdlib:map_get(
                Env,
                erlang:element(1, Normalized_definition)
            ) of
                {ok, Value} ->
                    do_parse(Normalized_definition, Value);

                {error, _} ->
                    {error,
                        {missing_key_error,
                            erlang:element(1, Normalized_definition)}}
            end
        end
    ).

-file("src/glenv.gleam", 81).
?DOC(
    " Load parses the environment variables and returns a Result containing the environment.\n"
    " Takes a decoder from the gleam/decode library and a list of definitions.\n"
    " \n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " type Env {\n"
    "   Env(hello: String, foo: Float, count: Int, is_on: Bool)\n"
    " }\n"
    "\n"
    " let definitions = [\n"
    "   #(\"HELLO\", glenv.String),\n"
    "   #(\"FOO\", glenv.Float),\n"
    "   #(\"COUNT\", glenv.Int),\n"
    "   #(\"IS_ON\", glenv.Bool),\n"
    " ]\n"
    "\n"
    " let decoder =\n"
    "   decode.into({\n"
    "     use hello <- decode.parameter\n"
    "     use foo <- decode.parameter\n"
    "     use count <- decode.parameter\n"
    "     use is_on <- decode.parameter\n"
    "\n"
    "     Env(hello: hello, foo: foo, count: count, is_on: is_on)\n"
    "   })\n"
    "   |> decode.field(\"HELLO\", decode.string)\n"
    "   |> decode.field(\"FOO\", decode.float)\n"
    "   |> decode.field(\"COUNT\", decode.int)\n"
    "   |> decode.field(\"IS_ON\", decode.bool)\n"
    "\n"
    " let assert Ok(env) = glenv.load(decoder, definitions)\n"
    "\n"
    " env.hello // \"world\"\n"
    " env.foo // 1.0\n"
    " env.count // 1\n"
    " env.is_on // True\n"
    " ```\n"
).
-spec load(gleam@dynamic@decode:decoder(EYE), list({binary(), type()})) -> {ok,
        EYE} |
    {error, env_error()}.
load(Decoder, Definitions) ->
    gleam@result:'try'(
        parse(Definitions),
        fun(Parsed_env) ->
            case begin
                _pipe = Parsed_env,
                _pipe@1 = maps:from_list(_pipe),
                _pipe@2 = gleam_stdlib:identity(_pipe@1),
                gleam@dynamic@decode:run(_pipe@2, Decoder)
            end of
                {ok, Env} ->
                    {ok, Env};

                {error, Err} ->
                    {error, {definition_mismatch_error, Err}}
            end
        end
    ).