package lua

import (
	"encoding/json"
	"strings"
	"testing"
)

// TestAdaptersPreserveToolCalls is the fleet-wide guard for the
// "orphaned tool result" class of bug: when an agent client replays a turn
// whose assistant message carries tool_calls, EVERY adapter must forward both
// the call and the attribution of its result. Dropping the call (or the
// tool_call_id / tool_name that ties the result to it) makes the model see a
// result for a call it never made and re-issue the same call forever.
//
// The input deliberately uses content:[] — the shape most agent clients emit
// for a tool-calling assistant turn with no text.
func TestAdaptersPreserveToolCalls(t *testing.T) {
	vm := NewVM(freshAdapterDir(t))
	if err := vm.Start(); err != nil {
		t.Fatal(err)
	}
	defer vm.Stop()

	body := `{"model":"m","messages":[
		{"role":"user","content":"read /tmp/x"},
		{"role":"assistant","content":[],"tool_calls":[{"id":"call_abc","type":"function","function":{"name":"read","arguments":"{\"path\":\"/tmp/x\"}"}}]},
		{"role":"tool","tool_call_id":"call_abc","content":"hello world"},
		{"role":"user","content":"summarize"}
	]}`
	const (
		callID   = "call_abc"
		fnName   = "read"
		toolOut  = "hello world"
		lastUser = "summarize"
	)

	// Adapters that identify a tool result by the call id.
	byID := []string{"openai", "deepseek", "github", "groq", "kimicode", "mistral",
		"sensenova", "trae", "agentrouter", "opencode", "anthropic"}

	for _, a := range byID {
		out, err := vm.Transform(a, "transform_request", body)
		if err != nil {
			t.Errorf("%s: transform_request: %v", a, err)
			continue
		}
		if !strings.Contains(out, callID) {
			t.Errorf("%s dropped the tool call id %q: %s", a, callID, out)
		}
		if !strings.Contains(out, fnName) {
			t.Errorf("%s dropped the function name %q: %s", a, fnName, out)
		}
		if !strings.Contains(out, toolOut) {
			t.Errorf("%s dropped the tool result: %s", a, out)
		}
		if !strings.Contains(out, lastUser) {
			t.Errorf("%s dropped the final user turn: %s", a, out)
		}
	}

	// Ollama identifies the result with tool_name (its API has no tool_call_id
	// on assistant turns) and takes arguments as an object, not a JSON string.
	out, err := vm.Transform("ollama", "transform_request", body)
	if err != nil {
		t.Fatalf("ollama: %v", err)
	}
	for _, want := range []string{`"tool_calls"`, fnName, `"tool_name"`, toolOut} {
		if !strings.Contains(out, want) {
			t.Errorf("ollama missing %s: %s", want, out)
		}
	}

	// Gemini identifies the result by function NAME and has no call id in its
	// wire format; both directions must be present as functionCall /
	// functionResponse parts, and the system role must move to
	// systemInstruction rather than sitting in contents.
	gBody := `{"model":"m","messages":[
		{"role":"system","content":"be brief"},
		{"role":"user","content":"read /tmp/x"},
		{"role":"assistant","content":[],"tool_calls":[{"id":"call_abc","type":"function","function":{"name":"read","arguments":"{\"path\":\"/tmp/x\"}"}}]},
		{"role":"tool","tool_call_id":"call_abc","content":"hello world"}
	]}`
	gout, err := vm.Transform("gemini", "transform_request", gBody)
	if err != nil {
		t.Fatalf("gemini: %v", err)
	}
	for _, want := range []string{`"functionCall"`, `"functionResponse"`, fnName, toolOut, `"systemInstruction"`} {
		if !strings.Contains(gout, want) {
			t.Errorf("gemini missing %s: %s", want, gout)
		}
	}
	// No message may keep the OpenAI-only roles inside contents.
	var greq struct {
		Contents []struct {
			Role string `json:"role"`
		} `json:"contents"`
	}
	if err := json.Unmarshal([]byte(gout), &greq); err != nil {
		t.Fatalf("gemini unmarshal: %v (%s)", err, gout)
	}
	for _, c := range greq.Contents {
		if c.Role != "user" && c.Role != "model" {
			t.Errorf("gemini contents carry an invalid role %q: %s", c.Role, gout)
		}
	}

	// Negative control: a text-only turn must still be forwarded verbatim.
	plain := `{"model":"m","messages":[{"role":"user","content":"just text"}]}`
	for _, a := range append(byID, "ollama", "gemini") {
		pout, err := vm.Transform(a, "transform_request", plain)
		if err != nil {
			t.Errorf("%s plain: %v", a, err)
			continue
		}
		if !strings.Contains(pout, "just text") {
			t.Errorf("%s dropped plain text: %s", a, pout)
		}
	}
}

// TestOpenCodeStreamOptionsOnlyWhenStreaming pins the fix for
// "stream_options should be set along with stream": OpenCode Go (and other
// strict OpenAI-compatible upstreams) reject a non-streaming request that
// carries stream_options, which broke every non-stream call through the
// opencode adapter.
func TestOpenCodeStreamOptionsOnlyWhenStreaming(t *testing.T) {
	vm := NewVM(freshAdapterDir(t))
	if err := vm.Start(); err != nil {
		t.Fatal(err)
	}
	defer vm.Stop()

	// non-streaming: stream_options must be absent entirely
	out, err := vm.Transform("opencode", "transform_request",
		`{"model":"m","messages":[{"role":"user","content":"hi"}]}`)
	if err != nil {
		t.Fatal(err)
	}
	if strings.Contains(out, "stream_options") {
		t.Fatalf("non-streaming request must not carry stream_options: %s", out)
	}

	// streaming: stream_options.include_usage must be set
	sout, err := vm.Transform("opencode", "transform_request",
		`{"model":"m","stream":true,"messages":[{"role":"user","content":"hi"}]}`)
	if err != nil {
		t.Fatal(err)
	}
	if !strings.Contains(sout, "stream_options") || !strings.Contains(sout, "include_usage") {
		t.Fatalf("streaming request must carry stream_options.include_usage: %s", sout)
	}
}

// TestOpenCodeGoVsZenReasoning pins the one behavioural difference that made a
// shared adapter wrong: OpenCode Go's thinking mode REQUIRES the assistant
// turn's reasoning_content to be echoed back ("The `reasoning_content` in the
// thinking mode must be passed back to the API"), while the Zen free pool must
// not receive it. Hence two purpose-built adapters.
func TestOpenCodeGoVsZenReasoning(t *testing.T) {
	vm := NewVM(freshAdapterDir(t))
	if err := vm.Start(); err != nil {
		t.Fatal(err)
	}
	defer vm.Stop()

	body := `{"model":"m","messages":[
		{"role":"user","content":"hi"},
		{"role":"assistant","content":"","reasoning_content":"I should read the file.","tool_calls":[{"id":"call_1","type":"function","function":{"name":"read","arguments":"{\"path\":\"/x\"}"}}]},
		{"role":"tool","tool_call_id":"call_1","content":"r"}
	]}`

	// Go: reasoning_content must survive, and the tool call must stay paired.
	gout, err := vm.Transform("opencodego", "transform_request", body)
	if err != nil {
		t.Fatalf("opencodego: %v", err)
	}
	if !strings.Contains(gout, "I should read the file.") {
		t.Errorf("opencodego must pass reasoning_content back (thinking mode requires it): %s", gout)
	}
	if !strings.Contains(gout, "call_1") || !strings.Contains(gout, "tool_call_id") {
		t.Errorf("opencodego must keep the tool call paired with its result: %s", gout)
	}

	// Zen: reasoning_content is stripped.
	zout, err := vm.Transform("opencodezen", "transform_request", body)
	if err != nil {
		t.Fatalf("opencodezen: %v", err)
	}
	if strings.Contains(zout, "I should read the file.") {
		t.Errorf("opencodezen must strip reasoning_content: %s", zout)
	}
	if !strings.Contains(zout, "call_1") {
		t.Errorf("opencodezen must still keep the tool call: %s", zout)
	}

	// An assistant turn that carries tool_calls but no reasoning_content must
	// get an empty one injected: Go validates that field on tool-calling turns
	// and 400s when it is absent, while most clients never send it.
	// Verified against the live endpoint that an empty string passes.
	bare := `{"model":"m","messages":[
		{"role":"user","content":"go"},
		{"role":"assistant","content":"","tool_calls":[{"id":"c1","type":"function","function":{"name":"read","arguments":"{}"}}]},
		{"role":"tool","tool_call_id":"c1","content":"r"}
	]}`
	bout, err := vm.Transform("opencodego", "transform_request", bare)
	if err != nil {
		t.Fatalf("opencodego bare: %v", err)
	}
	if !strings.Contains(bout, `"reasoning_content":""`) {
		t.Errorf("opencodego must inject an empty reasoning_content on a tool-calling turn: %s", bout)
	}
	// A plain assistant turn (no tool calls) must NOT gain the field.
	plainAsst := `{"model":"m","messages":[{"role":"user","content":"hi"},{"role":"assistant","content":"hello"}]}`
	pout, err := vm.Transform("opencodego", "transform_request", plainAsst)
	if err != nil {
		t.Fatal(err)
	}
	if strings.Contains(pout, "reasoning_content") {
		t.Errorf("opencodego must not inject reasoning_content on a plain assistant turn: %s", pout)
	}

	// Both must still omit stream_options on non-streaming requests.
	for _, a := range []string{"opencodego", "opencodezen"} {
		out, err := vm.Transform(a, "transform_request", `{"model":"m","messages":[{"role":"user","content":"hi"}]}`)
		if err != nil {
			t.Fatalf("%s: %v", a, err)
		}
		if strings.Contains(out, "stream_options") {
			t.Errorf("%s must not send stream_options when not streaming: %s", a, out)
		}
	}
}

// TestOpenCodeSessionIsStableForCache pins the session-derivation contract that
// makes the upstream prefix cache usable.
//
// Measured against the live OpenCode Go endpoint: the prefix cache is
// SESSION-scoped. Replaying the same 6032-token prompt hits 5888 cached tokens
// when the session id is fixed, and 0 when it changes per request. Deriving the
// session from meta.timestamp (the previous behaviour) meant every request was a
// new session, so the cache could never hit.
//
// The session must be stable WITHIN one conversation and differ BETWEEN
// conversations. Since generic OpenAI clients send no session id at all
// (verified by capturing real agent traffic: no user / session_id /
// conversation_id / metadata in the body, no session header), the conversation
// is fingerprinted by its FIRST user message — history is replayed every turn,
// so that message is invariant for the life of the conversation.
func TestOpenCodeSessionIsStableForCache(t *testing.T) {
	for _, name := range []string{"opencodego", "opencodezen"} {
		vm := NewVM(freshAdapterDir(t))
		if err := vm.Start(); err != nil {
			t.Fatal(err)
		}
		meta := func(ts int, body string) map[string]interface{} {
			return map[string]interface{}{
				"timestamp": ts,
				"body":      body,
				"source":    map[string]interface{}{"name": "somesource", "meta": nil},
			}
		}

		// Same conversation, later turn: history grew, first user msg unchanged.
		h1, err := vm.BuildHeaders(name, meta(1000,
			`{"messages":[{"role":"user","content":"fix the bug"},{"role":"assistant","content":"looking"}]}`))
		if err != nil {
			t.Fatalf("%s: %v", name, err)
		}
		h2, err := vm.BuildHeaders(name, meta(2000,
			`{"messages":[{"role":"user","content":"fix the bug"},{"role":"assistant","content":"looking"},{"role":"user","content":"and tests"}]}`))
		if err != nil {
			t.Fatalf("%s: %v", name, err)
		}
		// Different conversation.
		h3, err := vm.BuildHeaders(name, meta(3000,
			`{"messages":[{"role":"user","content":"an unrelated task"}]}`))
		if err != nil {
			t.Fatalf("%s: %v", name, err)
		}

		if h1["x-opencode-session"] == "" {
			t.Fatalf("%s: session header must be set", name)
		}
		if h1["x-opencode-session"] != h2["x-opencode-session"] {
			t.Errorf("%s: x-opencode-session must be STABLE across turns of one conversation "+
				"(%q vs %q) — the prefix cache is session-scoped", name, h1["x-opencode-session"], h2["x-opencode-session"])
		}
		if h1["x-opencode-session"] == h3["x-opencode-session"] {
			t.Errorf("%s: a different conversation must get a different session", name)
		}
		if h1["x-opencode-request"] == h2["x-opencode-request"] {
			t.Errorf("%s: x-opencode-request must differ per request", name)
		}
		// No user message at all falls back to per-source stability.
		h4, _ := vm.BuildHeaders(name, meta(4000, `{"messages":[{"role":"system","content":"s"}]}`))
		h5, _ := vm.BuildHeaders(name, meta(5000, `{"messages":[{"role":"system","content":"s"}]}`))
		if h4["x-opencode-session"] != h5["x-opencode-session"] {
			t.Errorf("%s: sessionless requests must still be stable per source", name)
		}
		vm.Stop()
	}
}