package ollama

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/http/httptest"
	"sync/atomic"
	"testing"
)

func TestTags_ParsesResponse(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/api/tags" {
			t.Errorf("unexpected path: %s", r.URL.Path)
		}
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(TagsResponse{
			Models: []ModelInfo{
				{Name: "qwen3:30b", Model: "qwen3:30b", Size: 19000000000},
				{Name: "nomic-embed-text", Model: "nomic-embed-text", Size: 300000000},
			},
		})
	}))
	defer srv.Close()

	client := NewClient(srv.URL, "")
	resp, err := client.Tags(context.Background())
	if err != nil {
		t.Fatalf("Tags: %v", err)
	}
	if len(resp.Models) != 2 {
		t.Fatalf("got %d models, want 2", len(resp.Models))
	}
	if resp.Models[0].Name != "qwen3:30b" {
		t.Errorf("first model = %q, want %q", resp.Models[0].Name, "qwen3:30b")
	}
}

func TestPs_ParsesResponse(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/api/ps" {
			t.Errorf("unexpected path: %s", r.URL.Path)
		}
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(PsResponse{
			Models: []RunningModel{
				{Name: "nomic-embed-text", Model: "nomic-embed-text", Size: 300000000},
			},
		})
	}))
	defer srv.Close()

	client := NewClient(srv.URL, "")
	resp, err := client.Ps(context.Background())
	if err != nil {
		t.Fatalf("Ps: %v", err)
	}
	if len(resp.Models) != 1 {
		t.Fatalf("got %d models, want 1", len(resp.Models))
	}
}

func TestChat_NonStreaming(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		body, _ := io.ReadAll(r.Body)
		var req ChatRequest
		if err := json.Unmarshal(body, &req); err != nil {
			t.Errorf("unmarshal: %v", err)
		}
		if req.Stream != nil && *req.Stream {
			t.Error("expected stream=false")
		}
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(ChatResponse{
			Model:   "qwen3:30b",
			Done:    true,
			Message: &Message{Role: "assistant", Content: "Hello!"},
		})
	}))
	defer srv.Close()

	client := NewClient(srv.URL, "")
	resp, ch, err := client.Chat(context.Background(), ChatRequest{
		Model:    "qwen3:30b",
		Messages: []Message{{Role: "user", Content: "hi"}},
	}, false)
	if err != nil {
		t.Fatalf("Chat: %v", err)
	}
	if ch != nil {
		t.Error("expected nil channel for non-streaming")
	}
	if resp == nil {
		t.Fatal("expected non-nil response")
	}
	if resp.Message.Content != "Hello!" {
		t.Errorf("content = %q, want %q", resp.Message.Content, "Hello!")
	}
}

func TestChat_Streaming(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/x-ndjson")
		flusher := w.(http.Flusher)

		chunks := []ChatResponse{
			{Model: "qwen3:30b", Done: false, Message: &Message{Role: "assistant", Content: "Hel"}},
			{Model: "qwen3:30b", Done: false, Message: &Message{Role: "assistant", Content: "lo"}},
			{Model: "qwen3:30b", Done: true, DoneReason: "stop"},
		}
		for _, c := range chunks {
			b, _ := json.Marshal(c)
			w.Write(b)
			w.Write([]byte("\n"))
			flusher.Flush()
		}
	}))
	defer srv.Close()

	client := NewClient(srv.URL, "")
	resp, ch, err := client.Chat(context.Background(), ChatRequest{
		Model:    "qwen3:30b",
		Messages: []Message{{Role: "user", Content: "hi"}},
	}, true)
	if err != nil {
		t.Fatalf("Chat: %v", err)
	}
	if resp != nil {
		t.Error("expected nil response for streaming")
	}
	if ch == nil {
		t.Fatal("expected non-nil channel for streaming")
	}

	var collected []ChatResponse
	for c := range ch {
		collected = append(collected, c)
	}
	if len(collected) != 3 {
		t.Fatalf("got %d chunks, want 3", len(collected))
	}
	if !collected[2].Done {
		t.Error("last chunk should have done=true")
	}
}

func TestEmbed_ParsesResponse(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/api/embed" {
			t.Errorf("unexpected path: %s", r.URL.Path)
		}
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(EmbedResponse{
			Model:      "nomic-embed-text",
			Embeddings: [][]float64{{0.1, 0.2, 0.3}},
		})
	}))
	defer srv.Close()

	client := NewClient(srv.URL, "")
	resp, err := client.Embed(context.Background(), EmbedRequest{
		Model: "nomic-embed-text",
		Input: json.RawMessage(`"test input"`),
	})
	if err != nil {
		t.Fatalf("Embed: %v", err)
	}
	if len(resp.Embeddings) != 1 {
		t.Fatalf("got %d embeddings, want 1", len(resp.Embeddings))
	}
	if len(resp.Embeddings[0]) != 3 {
		t.Errorf("embedding dim = %d, want 3", len(resp.Embeddings[0]))
	}
}

func TestClient_SetsAuthToken(t *testing.T) {
	var gotAuth string
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		gotAuth = r.Header.Get("Authorization")
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(TagsResponse{})
	}))
	defer srv.Close()

	client := NewClient(srv.URL, "my-secret-token")
	_, err := client.Tags(context.Background())
	if err != nil {
		t.Fatalf("Tags: %v", err)
	}
	if gotAuth != "Bearer my-secret-token" {
		t.Errorf("auth header = %q, want %q", gotAuth, "Bearer my-secret-token")
	}
}

func TestClient_ConnectionError(t *testing.T) {
	// Use a server that immediately closes.
	client := NewClient("http://127.0.0.1:1", "")
	_, err := client.Tags(context.Background())
	if err == nil {
		t.Fatal("expected error for unreachable target")
	}

	var connErr *ConnectionError
	if !errors.As(err, &connErr) {
		t.Errorf("expected *ConnectionError, got %T: %v", err, err)
	}
}

func TestClient_HTTPError(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		http.Error(w, `{"error":"bad model"}`, http.StatusBadRequest)
	}))
	defer srv.Close()

	client := NewClient(srv.URL, "")
	_, err := client.Tags(context.Background())
	if err == nil {
		t.Fatal("expected error for 400 response")
	}

	var httpErr *HTTPError
	if !errors.As(err, &httpErr) {
		t.Errorf("expected *HTTPError, got %T: %v", err, err)
	}
	if httpErr.StatusCode != http.StatusBadRequest {
		t.Errorf("status = %d, want %d", httpErr.StatusCode, http.StatusBadRequest)
	}
}

func TestRawChat_ForwardsBody(t *testing.T) {
	var gotBody []byte
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		gotBody, _ = io.ReadAll(r.Body)
		w.Header().Set("Content-Type", "application/json")
		w.Write([]byte(`{"done":true}`))
	}))
	defer srv.Close()

	client := NewClient(srv.URL, "")
	body := []byte(`{"model":"qwen3:30b","messages":[{"role":"user","content":"test"}]}`)
	resp, err := client.RawChat(context.Background(), body)
	if err != nil {
		t.Fatalf("RawChat: %v", err)
	}
	defer resp.Body.Close()

	if string(gotBody) != string(body) {
		t.Errorf("body mismatch: got %s, want %s", gotBody, body)
	}
}

func TestRawEmbed_ForwardsBody(t *testing.T) {
	var callCount atomic.Int32
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		callCount.Add(1)
		if r.URL.Path != "/api/embed" {
			t.Errorf("unexpected path: %s", r.URL.Path)
		}
		w.Header().Set("Content-Type", "application/json")
		w.Write([]byte(fmt.Sprintf(`{"model":"nomic-embed-text","embeddings":[[0.%d]]}`, callCount.Load())))
	}))
	defer srv.Close()

	client := NewClient(srv.URL, "")
	body := []byte(`{"model":"nomic-embed-text","input":"test"}`)
	resp, err := client.RawEmbed(context.Background(), body)
	if err != nil {
		t.Fatalf("RawEmbed: %v", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		t.Errorf("status = %d, want %d", resp.StatusCode, http.StatusOK)
	}
}