package ollama

import (
	"context"
	"encoding/json"
	"io"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"

	"gitea.stevedudenhoeffer.com/steve/go-llm/v2/provider"
)

// captureRequest is a tiny helper that records the inbound HTTP request and
// returns a configurable response body.
type captureRequest struct {
	method      string
	path        string
	authHeader  string
	contentType string
	body        []byte
	parsedBody  map[string]any
}

func newTestServer(t *testing.T, captured *captureRequest, status int, respBody string, respContentType string) *httptest.Server {
	t.Helper()
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		captured.method = r.Method
		captured.path = r.URL.Path
		captured.authHeader = r.Header.Get("Authorization")
		captured.contentType = r.Header.Get("Content-Type")
		body, _ := io.ReadAll(r.Body)
		captured.body = body
		_ = json.Unmarshal(body, &captured.parsedBody)
		if respContentType == "" {
			respContentType = "application/json"
		}
		w.Header().Set("Content-Type", respContentType)
		w.WriteHeader(status)
		_, _ = w.Write([]byte(respBody))
	}))
	t.Cleanup(srv.Close)
	return srv
}

func TestCompleteBasic(t *testing.T) {
	resp := `{
		"model": "kimi-k2.5",
		"message": {"role": "assistant", "content": "hello there"},
		"done": true,
		"done_reason": "stop",
		"prompt_eval_count": 10,
		"eval_count": 3
	}`
	cap := &captureRequest{}
	srv := newTestServer(t, cap, 200, resp, "")

	p := newNative("test-key", srv.URL)
	got, err := p.Complete(context.Background(), provider.Request{
		Model:    "kimi-k2.5",
		Messages: []provider.Message{{Role: "user", Content: "hi"}},
	})
	if err != nil {
		t.Fatalf("Complete: %v", err)
	}

	if cap.method != "POST" {
		t.Errorf("method: want POST, got %q", cap.method)
	}
	if cap.path != "/api/chat" {
		t.Errorf("path: want /api/chat, got %q", cap.path)
	}
	if cap.authHeader != "Bearer test-key" {
		t.Errorf("auth header: want %q, got %q", "Bearer test-key", cap.authHeader)
	}
	if cap.contentType != "application/json" {
		t.Errorf("content-type: want application/json, got %q", cap.contentType)
	}
	if cap.parsedBody["model"] != "kimi-k2.5" {
		t.Errorf("body.model: want kimi-k2.5, got %v", cap.parsedBody["model"])
	}
	if cap.parsedBody["stream"] != false {
		t.Errorf("body.stream: want false, got %v", cap.parsedBody["stream"])
	}
	msgs, _ := cap.parsedBody["messages"].([]any)
	if len(msgs) != 1 {
		t.Fatalf("messages: want 1 entry, got %d", len(msgs))
	}
	m0, _ := msgs[0].(map[string]any)
	if m0["role"] != "user" || m0["content"] != "hi" {
		t.Errorf("first message: want role=user content=hi, got %v", m0)
	}

	if got.Text != "hello there" {
		t.Errorf("Text: want %q, got %q", "hello there", got.Text)
	}
	if got.Usage == nil {
		t.Fatal("Usage: want non-nil")
	}
	if got.Usage.InputTokens != 10 || got.Usage.OutputTokens != 3 {
		t.Errorf("Usage: want input=10 output=3, got input=%d output=%d", got.Usage.InputTokens, got.Usage.OutputTokens)
	}
	if got.Usage.TotalTokens != 13 {
		t.Errorf("Usage.TotalTokens: want 13, got %d", got.Usage.TotalTokens)
	}
}

func TestCompleteNoAuthHeaderWhenLocal(t *testing.T) {
	resp := `{"message":{"role":"assistant","content":"ok"},"done":true}`
	cap := &captureRequest{}
	srv := newTestServer(t, cap, 200, resp, "")

	p := newNative("", srv.URL)
	if _, err := p.Complete(context.Background(), provider.Request{
		Model:    "llama3.2",
		Messages: []provider.Message{{Role: "user", Content: "hi"}},
	}); err != nil {
		t.Fatalf("Complete: %v", err)
	}

	if cap.authHeader != "" {
		t.Errorf("auth header: want empty (local mode), got %q", cap.authHeader)
	}
}

func TestVisionImagesEncoded(t *testing.T) {
	resp := `{"message":{"role":"assistant","content":"a cat"},"done":true}`
	cap := &captureRequest{}
	srv := newTestServer(t, cap, 200, resp, "")

	p := newNative("", srv.URL)
	if _, err := p.Complete(context.Background(), provider.Request{
		Model: "llava",
		Messages: []provider.Message{{
			Role:    "user",
			Content: "what's in this?",
			Images: []provider.Image{
				{Base64: "AAAA", ContentType: "image/png"},
			},
		}},
	}); err != nil {
		t.Fatalf("Complete: %v", err)
	}

	msgs, _ := cap.parsedBody["messages"].([]any)
	if len(msgs) != 1 {
		t.Fatalf("messages: want 1, got %d", len(msgs))
	}
	m0, _ := msgs[0].(map[string]any)
	imgs, _ := m0["images"].([]any)
	if len(imgs) != 1 {
		t.Fatalf("images: want 1 entry, got %d (msg=%v)", len(imgs), m0)
	}
	if imgs[0] != "AAAA" {
		t.Errorf("images[0]: want raw base64 AAAA, got %v", imgs[0])
	}
}

func TestThinkingField(t *testing.T) {
	cases := []struct {
		name      string
		reasoning string
		want      any // expected value of "think" in body, or nil if absent
	}{
		{"absent", "", nil},
		{"high", "high", "high"},
		{"low", "low", "low"},
		{"medium", "medium", "medium"},
		{"true", "true", true},
		{"false", "false", false},
	}
	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			resp := `{"message":{"role":"assistant","content":"ok"},"done":true}`
			cap := &captureRequest{}
			srv := newTestServer(t, cap, 200, resp, "")

			p := newNative("", srv.URL)
			_, err := p.Complete(context.Background(), provider.Request{
				Model:     "kimi-k2.5",
				Messages:  []provider.Message{{Role: "user", Content: "hi"}},
				Reasoning: c.reasoning,
			})
			if err != nil {
				t.Fatalf("Complete: %v", err)
			}
			got, present := cap.parsedBody["think"]
			if c.want == nil {
				if present {
					t.Errorf("think field should be absent, got %v", got)
				}
				return
			}
			if !present {
				t.Fatalf("think field absent; want %v", c.want)
			}
			if got != c.want {
				t.Errorf("think: want %v (%T), got %v (%T)", c.want, c.want, got, got)
			}
		})
	}
}

func TestToolRoundTrip(t *testing.T) {
	t.Run("response tool_calls convert to provider.Response", func(t *testing.T) {
		resp := `{
			"message": {
				"role": "assistant",
				"content": "",
				"tool_calls": [
					{"function": {"name": "search", "arguments": {"query": "foo"}}}
				]
			},
			"done": true,
			"prompt_eval_count": 5,
			"eval_count": 2
		}`
		cap := &captureRequest{}
		srv := newTestServer(t, cap, 200, resp, "")

		p := newNative("", srv.URL)
		got, err := p.Complete(context.Background(), provider.Request{
			Model:    "kimi-k2.5",
			Messages: []provider.Message{{Role: "user", Content: "hi"}},
			Tools: []provider.ToolDef{
				{
					Name:        "search",
					Description: "Run a search",
					Schema: map[string]any{
						"type": "object",
						"properties": map[string]any{
							"query": map[string]any{"type": "string"},
						},
					},
				},
			},
		})
		if err != nil {
			t.Fatalf("Complete: %v", err)
		}

		// Verify request shape: tools array present.
		toolsArr, _ := cap.parsedBody["tools"].([]any)
		if len(toolsArr) != 1 {
			t.Fatalf("tools: want 1 entry, got %d", len(toolsArr))
		}
		t0, _ := toolsArr[0].(map[string]any)
		if t0["type"] != "function" {
			t.Errorf("tools[0].type: want function, got %v", t0["type"])
		}
		fn, _ := t0["function"].(map[string]any)
		if fn["name"] != "search" {
			t.Errorf("tools[0].function.name: want search, got %v", fn["name"])
		}

		// Verify response conversion.
		if len(got.ToolCalls) != 1 {
			t.Fatalf("ToolCalls: want 1, got %d", len(got.ToolCalls))
		}
		tc := got.ToolCalls[0]
		if tc.Name != "search" {
			t.Errorf("ToolCall.Name: want search, got %q", tc.Name)
		}
		// Arguments should be valid JSON containing query=foo
		var args map[string]any
		if err := json.Unmarshal([]byte(tc.Arguments), &args); err != nil {
			t.Fatalf("ToolCall.Arguments not valid JSON: %v (got %q)", err, tc.Arguments)
		}
		if args["query"] != "foo" {
			t.Errorf("ToolCall.Arguments.query: want foo, got %v", args["query"])
		}
	})

	t.Run("subsequent request includes assistant tool_calls and tool-role response", func(t *testing.T) {
		resp := `{"message":{"role":"assistant","content":"done"},"done":true}`
		cap := &captureRequest{}
		srv := newTestServer(t, cap, 200, resp, "")

		p := newNative("", srv.URL)
		_, err := p.Complete(context.Background(), provider.Request{
			Model: "kimi-k2.5",
			Messages: []provider.Message{
				{Role: "user", Content: "search foo"},
				{
					Role: "assistant",
					ToolCalls: []provider.ToolCall{{
						ID:        "tc1",
						Name:      "search",
						Arguments: `{"query":"foo"}`,
					}},
				},
				{
					Role:       "tool",
					ToolCallID: "tc1",
					Content:    `{"result":"bar"}`,
				},
			},
		})
		if err != nil {
			t.Fatalf("Complete: %v", err)
		}

		msgs, _ := cap.parsedBody["messages"].([]any)
		if len(msgs) != 3 {
			t.Fatalf("messages: want 3, got %d", len(msgs))
		}

		// Assistant message must carry tool_calls with the JSON-object arguments.
		asst, _ := msgs[1].(map[string]any)
		if asst["role"] != "assistant" {
			t.Errorf("msgs[1].role: want assistant, got %v", asst["role"])
		}
		tc, _ := asst["tool_calls"].([]any)
		if len(tc) != 1 {
			t.Fatalf("assistant.tool_calls: want 1, got %d", len(tc))
		}
		fn, _ := tc[0].(map[string]any)["function"].(map[string]any)
		if fn["name"] != "search" {
			t.Errorf("assistant.tool_calls[0].function.name: want search, got %v", fn["name"])
		}
		args, _ := fn["arguments"].(map[string]any)
		if args["query"] != "foo" {
			t.Errorf("assistant.tool_calls[0].function.arguments.query: want foo, got %v", args["query"])
		}

		// Tool-role message must have role=tool, tool_call_id, and content.
		tool, _ := msgs[2].(map[string]any)
		if tool["role"] != "tool" {
			t.Errorf("msgs[2].role: want tool, got %v", tool["role"])
		}
		if tool["tool_call_id"] != "tc1" {
			t.Errorf("msgs[2].tool_call_id: want tc1, got %v", tool["tool_call_id"])
		}
		if !strings.Contains(toString(tool["content"]), "bar") {
			t.Errorf("msgs[2].content: want to contain bar, got %v", tool["content"])
		}
	})
}

func toString(v any) string {
	if s, ok := v.(string); ok {
		return s
	}
	b, _ := json.Marshal(v)
	return string(b)
}

// streamServer returns an httptest.Server that writes the given NDJSON lines
// (each terminated with \n) as the response body.
func streamServer(t *testing.T, captured *captureRequest, lines []string) *httptest.Server {
	t.Helper()
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		captured.method = r.Method
		captured.path = r.URL.Path
		captured.authHeader = r.Header.Get("Authorization")
		captured.contentType = r.Header.Get("Content-Type")
		body, _ := io.ReadAll(r.Body)
		captured.body = body
		_ = json.Unmarshal(body, &captured.parsedBody)
		w.Header().Set("Content-Type", "application/x-ndjson")
		w.WriteHeader(200)
		flusher, _ := w.(http.Flusher)
		for _, line := range lines {
			_, _ = w.Write([]byte(line + "\n"))
			if flusher != nil {
				flusher.Flush()
			}
		}
	}))
	t.Cleanup(srv.Close)
	return srv
}

func collectStream(t *testing.T, p *Provider, req provider.Request) []provider.StreamEvent {
	t.Helper()
	events := make(chan provider.StreamEvent, 64)
	done := make(chan error, 1)
	go func() {
		done <- p.Stream(context.Background(), req, events)
	}()
	var out []provider.StreamEvent
	timeout := time.After(5 * time.Second)
	streamErrored := false
loop:
	for {
		select {
		case ev, ok := <-events:
			if !ok {
				break loop
			}
			out = append(out, ev)
			if ev.Type == provider.StreamEventError {
				streamErrored = true
			}
		case err := <-done:
			if err != nil && !streamErrored {
				t.Fatalf("Stream returned error: %v", err)
			}
			// Drain any final events buffered in the channel.
			for {
				select {
				case ev, ok := <-events:
					if !ok {
						return out
					}
					out = append(out, ev)
				default:
					return out
				}
			}
		case <-timeout:
			t.Fatal("Stream did not complete within 5s")
		}
	}
	if err := <-done; err != nil && !streamErrored {
		t.Fatalf("Stream returned error: %v", err)
	}
	return out
}

func TestStreamBasic(t *testing.T) {
	lines := []string{
		`{"message":{"role":"assistant","content":"hello"},"done":false}`,
		`{"message":{"role":"assistant","content":" world","thinking":"reasoning"},"done":false}`,
		`{"message":{"role":"assistant","content":""},"done":true,"prompt_eval_count":12,"eval_count":2}`,
	}
	cap := &captureRequest{}
	srv := streamServer(t, cap, lines)

	p := newNative("", srv.URL)
	events := collectStream(t, p, provider.Request{
		Model:    "kimi-k2.5",
		Messages: []provider.Message{{Role: "user", Content: "hi"}},
	})

	// Verify request shape: stream:true.
	if cap.parsedBody["stream"] != true {
		t.Errorf("body.stream: want true, got %v", cap.parsedBody["stream"])
	}

	// Filter to relevant events (text, thinking, done) preserving order.
	var kinds []string
	var texts []string
	var doneEvent *provider.StreamEvent
	for i, ev := range events {
		switch ev.Type {
		case provider.StreamEventText:
			kinds = append(kinds, "text")
			texts = append(texts, ev.Text)
		case provider.StreamEventThinking:
			kinds = append(kinds, "thinking")
			texts = append(texts, ev.Text)
		case provider.StreamEventDone:
			kinds = append(kinds, "done")
			e := events[i]
			doneEvent = &e
		}
	}

	wantKinds := []string{"text", "thinking", "text", "done"}
	if !equalStrings(kinds, wantKinds) {
		t.Errorf("event kinds: want %v, got %v", wantKinds, kinds)
	}
	if len(texts) >= 3 {
		if texts[0] != "hello" {
			t.Errorf("first text: want hello, got %q", texts[0])
		}
		if texts[1] != "reasoning" {
			t.Errorf("thinking: want reasoning, got %q", texts[1])
		}
		if texts[2] != " world" {
			t.Errorf("second text: want \" world\", got %q", texts[2])
		}
	}
	if doneEvent == nil || doneEvent.Response == nil {
		t.Fatal("Done event missing Response")
	}
	if doneEvent.Response.Text != "hello world" {
		t.Errorf("Response.Text: want %q, got %q", "hello world", doneEvent.Response.Text)
	}
	if doneEvent.Response.Thinking != "reasoning" {
		t.Errorf("Response.Thinking: want %q, got %q", "reasoning", doneEvent.Response.Thinking)
	}
	if doneEvent.Response.Usage == nil {
		t.Fatal("Response.Usage missing")
	}
	if doneEvent.Response.Usage.InputTokens != 12 || doneEvent.Response.Usage.OutputTokens != 2 {
		t.Errorf("Usage: want input=12 output=2, got input=%d output=%d", doneEvent.Response.Usage.InputTokens, doneEvent.Response.Usage.OutputTokens)
	}
}

func TestStreamToolDeltaAccumulation(t *testing.T) {
	lines := []string{
		`{"message":{"role":"assistant","content":"","tool_calls":[{"id":"tc1","function":{"name":"search","arguments":"{\"que"}}]},"done":false}`,
		`{"message":{"role":"assistant","content":"","tool_calls":[{"id":"tc1","function":{"arguments":"ry\":\"foo\"}"}}]},"done":false}`,
		`{"message":{"role":"assistant","content":""},"done":true,"prompt_eval_count":4,"eval_count":1}`,
	}
	cap := &captureRequest{}
	srv := streamServer(t, cap, lines)

	p := newNative("", srv.URL)
	events := collectStream(t, p, provider.Request{
		Model:    "kimi-k2.5",
		Messages: []provider.Message{{Role: "user", Content: "search foo"}},
		Tools: []provider.ToolDef{
			{Name: "search", Schema: map[string]any{"type": "object"}},
		},
	})

	// Build a slim trace of tool events.
	type traceEntry struct {
		kind string
		args string
		name string
		id   string
	}
	var trace []traceEntry
	var doneEvent *provider.StreamEvent
	for i, ev := range events {
		switch ev.Type {
		case provider.StreamEventToolStart:
			trace = append(trace, traceEntry{kind: "start", name: ev.ToolCall.Name, id: ev.ToolCall.ID})
		case provider.StreamEventToolDelta:
			trace = append(trace, traceEntry{kind: "delta", args: ev.ToolCall.Arguments})
		case provider.StreamEventToolEnd:
			trace = append(trace, traceEntry{kind: "end", args: ev.ToolCall.Arguments, name: ev.ToolCall.Name, id: ev.ToolCall.ID})
		case provider.StreamEventDone:
			e := events[i]
			doneEvent = &e
		}
	}

	if len(trace) != 4 {
		t.Fatalf("trace: want 4 entries (start, delta, delta, end), got %d: %+v", len(trace), trace)
	}
	if trace[0].kind != "start" || trace[0].name != "search" || trace[0].id != "tc1" {
		t.Errorf("trace[0]: want start search tc1, got %+v", trace[0])
	}
	if trace[1].kind != "delta" || trace[1].args != `{"que` {
		t.Errorf("trace[1]: want delta args=%q, got %+v", `{"que`, trace[1])
	}
	if trace[2].kind != "delta" || trace[2].args != `ry":"foo"}` {
		t.Errorf("trace[2]: want delta args=%q, got %+v", `ry":"foo"}`, trace[2])
	}
	if trace[3].kind != "end" || trace[3].args != `{"query":"foo"}` {
		t.Errorf("trace[3]: want end args=%q, got %+v", `{"query":"foo"}`, trace[3])
	}

	if doneEvent == nil || doneEvent.Response == nil {
		t.Fatal("Done event missing Response")
	}
	if len(doneEvent.Response.ToolCalls) != 1 {
		t.Fatalf("Done.Response.ToolCalls: want 1, got %d", len(doneEvent.Response.ToolCalls))
	}
	tc := doneEvent.Response.ToolCalls[0]
	if tc.ID != "tc1" || tc.Name != "search" || tc.Arguments != `{"query":"foo"}` {
		t.Errorf("Done.Response.ToolCalls[0]: want tc1/search/{...}, got %+v", tc)
	}
}

func equalStrings(a, b []string) bool {
	if len(a) != len(b) {
		return false
	}
	for i := range a {
		if a[i] != b[i] {
			return false
		}
	}
	return true
}