library(aisdk)

test_that("Custom provider validates inputs", {
    expect_error(
        create_custom_provider(provider_name = "", base_url = "https://api.example.com"),
        "`provider_name` must be a non-empty string."
    )

    expect_error(
        create_custom_provider(provider_name = "test", base_url = ""),
        "`base_url` must be a valid URL string."
    )

    expect_error(
        create_custom_provider(provider_name = "test", base_url = "https://api.example.com", api_format = "invalid_format"),
        "'arg' should be one of "
    )
})

test_that("Custom provider correctly routes to base classes", {
    # Chat Completions
    p1 <- create_custom_provider(
        "custom1",
        "https://api.test1.com",
        api_format = "chat_completions"
    )

    m1 <- p1$language_model("model-1")
    expect_s3_class(m1, "OpenAILanguageModel")

    # Responses API
    p2 <- create_custom_provider(
        "custom2",
        "https://api.test2.com",
        api_format = "responses"
    )

    m2 <- p2$language_model("model-2")
    expect_s3_class(m2, "OpenAIResponsesLanguageModel")

    # Anthropic Messages API
    p3 <- create_custom_provider(
        "custom3",
        "https://api.test3.com",
        api_format = "anthropic_messages"
    )

    m3 <- p3$language_model("model-3")
    expect_s3_class(m3, "AnthropicLanguageModel")
})

test_that("Custom provider injects capabilities correctly", {
    p_default <- create_custom_provider(
        "test",
        "https://api.example.com",
        use_max_completion_tokens = FALSE
    )
    m_default <- p_default$language_model("model-x")

    expect_false(m_default$has_capability("is_reasoning_model"))

    p_reasoning <- create_custom_provider(
        "test",
        "https://api.example.com",
        use_max_completion_tokens = TRUE
    )
    m_reasoning <- p_reasoning$language_model("model-y")

    expect_true(m_reasoning$has_capability("is_reasoning_model"))
})

test_that("Custom provider defaults to conservative compatibility flags", {
    p <- create_custom_provider(
        "compat",
        "https://api.example.com/v1"
    )
    m <- p$language_model("test-model")

    expect_false(m$has_capability("native_tool_calling"))
    expect_true(isTRUE(m$get_config()$disable_stream_options))
})

test_that("Custom provider stores multiple base URLs for failover", {
    p <- create_custom_provider(
        "failover",
        "https://primary.example/v1, https://backup.example/v1"
    )
    m <- p$language_model("test-model")

    expect_equal(m$get_config()$base_url, "https://primary.example/v1")
    expect_equal(m$get_config()$base_urls, c("https://primary.example/v1", "https://backup.example/v1"))
})

test_that("Custom Anthropic provider builds failover endpoint URLs", {
    p <- create_custom_provider(
        "failover_anthropic",
        "https://primary.example/v1, https://backup.example/v1",
        api_format = "anthropic_messages"
    )
    m <- p$language_model("test-model")
    captured_url <- NULL

    testthat::local_mocked_bindings(
        post_to_api = function(url, headers, body, ...) {
            captured_url <<- url
            list(
                content = list(list(type = "text", text = "ok")),
                stop_reason = "end_turn",
                usage = list(input_tokens = 1, output_tokens = 1)
            )
        },
        .package = "aisdk"
    )

    m$do_generate(list(
        messages = list(list(role = "user", content = "test")),
        max_tokens = 16
    ))

    expect_equal(captured_url, c(
        "https://primary.example/v1/messages",
        "https://backup.example/v1/messages"
    ))
})

test_that("Custom provider overrides endpoint correctly", {
  p <- create_custom_provider(
    "test_endpoint",
        "https://api.custom-endpoint.com/v1",
        api_key = "test-key"
    )
    m <- p$language_model("test-model")

    # Test the private configuration directly, to ensure base_url was set
    # instead of decaying to default environment-level defaults.
    # Since the underlying `config` logic is abstracted, we can check
    # the build_payload or url generation logic directly.

    payload <- m$build_payload(list(
        messages = list(list(role = "user", content = "test"))
    ))

    expect_equal(payload$url, "https://api.custom-endpoint.com/v1/chat/completions")
    expect_equal(payload$headers[["Authorization"]], "Bearer test-key")
})

test_that("Custom provider omits auth headers when API key is blank", {
    openai_provider <- create_custom_provider(
        "no_key_openai",
        "https://api.custom-endpoint.com/v1",
        api_key = "",
        api_format = "chat_completions"
    )
    openai_model <- openai_provider$language_model("test-model")
    openai_payload <- openai_model$build_payload(list(
        messages = list(list(role = "user", content = "test"))
    ))

    expect_null(openai_payload$headers[["Authorization"]])

    anthropic_provider <- create_custom_provider(
        "no_key_anthropic",
        "https://api.custom-endpoint.com/v1",
        api_key = "",
        api_format = "anthropic_messages"
    )
    anthropic_model <- anthropic_provider$language_model("test-model")
    captured_headers <- NULL

    local_mocked_bindings(
        post_to_api = function(url, headers, body, ...) {
            captured_headers <<- headers
            list(
                content = list(list(type = "text", text = "ok")),
                stop_reason = "end_turn",
                usage = list(input_tokens = 1, output_tokens = 1)
            )
        },
        .package = "aisdk"
    )

    anthropic_model$do_generate(list(
        messages = list(list(role = "user", content = "test")),
        max_tokens = 16
    ))

    expect_false("x-api-key" %in% names(captured_headers))
    expect_equal(captured_headers[["Content-Type"]], "application/json")
})

test_that("Custom provider integrates with Registry", {
    registry <- ProviderRegistry$new()
    p <- create_custom_provider("my_test", "https://api.test.com")

    registry$register("my_test", p)

    m <- registry$language_model("my_test:custom-model-abc")
    expect_s3_class(m, "OpenAILanguageModel")
})

test_that("Default registry resolves custom provider from environment", {
    registry_env <- get(".registry_env", envir = asNamespace("aisdk"))
    old_base <- Sys.getenv("AISDK_CUSTOM_BASE_URL", unset = "")
    old_bases <- Sys.getenv("AISDK_CUSTOM_BASE_URLS", unset = "")
    old_key <- Sys.getenv("AISDK_CUSTOM_API_KEY", unset = "")
    old_format <- Sys.getenv("AISDK_CUSTOM_API_FORMAT", unset = "")
    old_reasoning <- Sys.getenv("AISDK_CUSTOM_USE_MAX_COMPLETION_TOKENS", unset = "")
    old_default <- registry_env$default %||% NULL

    on.exit({
        if (nzchar(old_base)) Sys.setenv(AISDK_CUSTOM_BASE_URL = old_base) else Sys.unsetenv("AISDK_CUSTOM_BASE_URL")
        if (nzchar(old_bases)) Sys.setenv(AISDK_CUSTOM_BASE_URLS = old_bases) else Sys.unsetenv("AISDK_CUSTOM_BASE_URLS")
        if (nzchar(old_key)) Sys.setenv(AISDK_CUSTOM_API_KEY = old_key) else Sys.unsetenv("AISDK_CUSTOM_API_KEY")
        if (nzchar(old_format)) Sys.setenv(AISDK_CUSTOM_API_FORMAT = old_format) else Sys.unsetenv("AISDK_CUSTOM_API_FORMAT")
        if (nzchar(old_reasoning)) Sys.setenv(AISDK_CUSTOM_USE_MAX_COMPLETION_TOKENS = old_reasoning) else Sys.unsetenv("AISDK_CUSTOM_USE_MAX_COMPLETION_TOKENS")
        registry_env$default <- old_default
    }, add = TRUE)

    Sys.setenv(
        AISDK_CUSTOM_BASE_URL = "https://api.custom-env.example/v1",
        AISDK_CUSTOM_BASE_URLS = "https://api.custom-env-backup.example/v1",
        AISDK_CUSTOM_API_KEY = "sk-custom-env",
        AISDK_CUSTOM_API_FORMAT = "chat_completions"
    )
    Sys.unsetenv("AISDK_CUSTOM_USE_MAX_COMPLETION_TOKENS")
    registry_env$default <- NULL

    registry <- get_default_registry()
    model <- registry$language_model("custom:test-model")

    expect_s3_class(model, "OpenAILanguageModel")
    expect_equal(model$get_config()$base_urls, c(
        "https://api.custom-env.example/v1",
        "https://api.custom-env-backup.example/v1"
    ))
})

test_that("Default registry resolves custom providers from aisdk.yaml", {
    registry_env <- get(".registry_env", envir = asNamespace("aisdk"))
    old_default <- registry_env$default %||% NULL
    old_wd <- getwd()
    tmp <- tempfile("aisdk-config-")
    dir.create(tmp)
    on.exit({
        setwd(old_wd)
        registry_env$default <- old_default
    }, add = TRUE)
    setwd(tmp)

    writeLines(c(
        "model_providers:",
        "  yulab:",
        "    type: custom",
        "    base_url: https://primary.yulab.example/v1",
        "    backup_base_urls:",
        "      - https://backup.yulab.example/v1",
        "    wire_api: responses",
        "    api_key_env: YULAB_TEST_API_KEY",
        "    disable_stream_options: true",
        "    supports_native_tools: false"
    ), "aisdk.yaml")
    Sys.setenv(YULAB_TEST_API_KEY = "sk-yulab")
    on.exit(Sys.unsetenv("YULAB_TEST_API_KEY"), add = TRUE)

    registry_env$default <- NULL
    model <- get_default_registry()$language_model("yulab:gpt-5.5")

    expect_s3_class(model, "OpenAIResponsesLanguageModel")
    expect_equal(model$get_config()$provider_name, "yulab")
    expect_equal(model$get_config()$api_key, "sk-yulab")
    expect_equal(model$get_config()$base_urls, c(
        "https://primary.yulab.example/v1",
        "https://backup.yulab.example/v1"
    ))
})

test_that("Configured providers accept base_urls without separate base_url", {
    registry_env <- get(".registry_env", envir = asNamespace("aisdk"))
    old_default <- registry_env$default %||% NULL
    old_wd <- getwd()
    tmp <- tempfile("aisdk-config-")
    dir.create(tmp)
    on.exit({
        setwd(old_wd)
        registry_env$default <- old_default
    }, add = TRUE)
    setwd(tmp)

    writeLines(c(
        "model_providers:",
        "  yulab:",
        "    type: custom",
        "    base_urls:",
        "      - https://primary.yulab.example/v1",
        "      - https://backup.yulab.example/v1",
        "    wire_api: responses"
    ), "aisdk.yaml")

    registry_env$default <- NULL
    model <- get_default_registry()$language_model("yulab:gpt-5.5")

    expect_equal(model$get_config()$base_url, "https://primary.yulab.example/v1")
    expect_equal(model$get_config()$base_urls, c(
        "https://primary.yulab.example/v1",
        "https://backup.yulab.example/v1"
    ))
})