package anthropic

import (
	"testing"

	"gitea.stevedudenhoeffer.com/steve/go-llm/v2/provider"
	anth "github.com/liushuangls/go-anthropic/v2"
)

// TestBuildRequest_MultiSystemUsedWhenSystemPresent verifies that after the
// refactor, the Anthropic provider uses MultiSystem (multi-part) rather than
// the flat System string when a system message is present. This is
// behavior-preserving — the upstream client's MarshalJSON prefers
// MultiSystem when both are set.
func TestBuildRequest_MultiSystemUsedWhenSystemPresent(t *testing.T) {
	p := New("test-key")
	req := provider.Request{
		Model: "claude-sonnet-4-6",
		Messages: []provider.Message{
			{Role: "system", Content: "you are helpful"},
			{Role: "user", Content: "hello"},
		},
	}
	anthReq := p.buildRequest(req)

	if len(anthReq.MultiSystem) != 1 {
		t.Fatalf("expected 1 MultiSystem part, got %d", len(anthReq.MultiSystem))
	}
	if anthReq.MultiSystem[0].Text != "you are helpful" {
		t.Errorf("expected MultiSystem text 'you are helpful', got %q", anthReq.MultiSystem[0].Text)
	}
	if anthReq.MultiSystem[0].Type != "text" {
		t.Errorf("expected MultiSystem type 'text', got %q", anthReq.MultiSystem[0].Type)
	}
	if anthReq.System != "" {
		t.Errorf("expected System string to be empty when MultiSystem is used, got %q", anthReq.System)
	}
}

// TestBuildRequest_MultipleSystemMessagesConcatenated verifies that multiple
// system messages are joined into a single MultiSystem part (preserving
// existing newline-joined behavior from the old code).
func TestBuildRequest_MultipleSystemMessagesConcatenated(t *testing.T) {
	p := New("test-key")
	req := provider.Request{
		Model: "claude-sonnet-4-6",
		Messages: []provider.Message{
			{Role: "system", Content: "part A"},
			{Role: "system", Content: "part B"},
			{Role: "user", Content: "hello"},
		},
	}
	anthReq := p.buildRequest(req)

	if len(anthReq.MultiSystem) != 1 {
		t.Fatalf("expected 1 MultiSystem part after concat, got %d", len(anthReq.MultiSystem))
	}
	expected := "part A\npart B"
	if anthReq.MultiSystem[0].Text != expected {
		t.Errorf("expected MultiSystem text %q, got %q", expected, anthReq.MultiSystem[0].Text)
	}
}

// TestBuildRequest_NoSystemMessage verifies that when there's no system
// message, both System and MultiSystem are empty.
func TestBuildRequest_NoSystemMessage(t *testing.T) {
	p := New("test-key")
	req := provider.Request{
		Model: "claude-sonnet-4-6",
		Messages: []provider.Message{
			{Role: "user", Content: "hello"},
		},
	}
	anthReq := p.buildRequest(req)

	if len(anthReq.MultiSystem) != 0 {
		t.Errorf("expected empty MultiSystem when no system message, got %d parts", len(anthReq.MultiSystem))
	}
	if anthReq.System != "" {
		t.Errorf("expected empty System string, got %q", anthReq.System)
	}
	// Silences the unused import warning in this file until Task 5.
	_ = anth.CacheControlTypeEphemeral
}