package proxy

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"

	"forgejo.riotpiao.com/rock/homelab-frontend/internal/config"
)

// TestSystemoneRoutesByModel verifies POST /v1/systemone dispatches on the body
// "model" field instead of falling through to path-based route lookup. Before
// that path joined body dispatch, the request reached the route table and
// failed with "no routes configured" when no routes were defined.
func TestSystemoneRoutesByModel(t *testing.T) {
	clefCalled := false
	clefServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		clefCalled = true
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusOK)
		fmt.Fprint(w, `{"decision":"allow"}`)
	}))
	defer clefServer.Close()

	clefAddr := strings.TrimPrefix(clefServer.URL, "http://")

	cfg := &config.Config{
		Models: map[string]*config.ModelUpstream{
			"clef-flash": {
				Name:    "clef-flash",
				Address: clefAddr,
			},
		},
		Routes: make(map[string]*config.Route),
	}

	handler := New(cfg)
	defer handler.Close()

	server := httptest.NewServer(handler)
	defer server.Close()

	resp, err := http.Post(
		server.URL+"/v1/systemone",
		"application/json",
		bytes.NewReader([]byte(`{"model":"clef-flash","state":"x","questions":{}}`)),
	)
	if err != nil {
		t.Fatalf("request failed: %v", err)
	}
	defer resp.Body.Close()

	if !clefCalled {
		t.Errorf("upstream clef-flash service was not called")
	}

	if resp.StatusCode != http.StatusOK {
		t.Errorf("expected 200 for known systemone model, got %d", resp.StatusCode)
	}

	body, readErr := io.ReadAll(resp.Body)
	if readErr != nil {
		t.Fatalf("failed to read response body: %v", readErr)
	}
	if strings.Contains(string(body), "no routes configured") {
		t.Errorf("systemone request fell through to route lookup: %s", string(body))
	}
	if !strings.Contains(string(body), `"decision":"allow"`) {
		t.Errorf("expected upstream response body, got %s", string(body))
	}
}

// TestSystemoneUnknownModelValidationError verifies an unknown model on
// /v1/systemone returns the same modelValidationError kind as the other three
// body-dispatched paths.
func TestSystemoneUnknownModelValidationError(t *testing.T) {
	cfg := &config.Config{
		Models: map[string]*config.ModelUpstream{
			"clef-flash": {
				Name:    "clef-flash",
				Address: "localhost:9000",
			},
		},
		Routes: make(map[string]*config.Route),
	}

	handler := New(cfg)
	defer handler.Close()

	paths := []string{
		"/v1/chat/completions",
		"/v1/embeddings",
		"/v1/rerank",
		"/v1/systemone",
	}
	for _, path := range paths {
		req := httptest.NewRequest(
			"POST",
			path,
			strings.NewReader(`{"model":"unknown-model"}`),
		)
		route, err := handler.RouteRequest(req)
		if route != nil {
			t.Errorf("%s: expected nil route for unknown model", path)
		}
		var validationErr *modelValidationError
		if !errors.As(err, &validationErr) {
			t.Fatalf("%s: expected modelValidationError, got %v", path, err)
		}
		if validationErr.Kind != "unknown_model" {
			t.Errorf("%s: expected kind unknown_model, got %s", path, validationErr.Kind)
		}
	}
}

// TestSystemoneUpstreamPathNotRewritten verifies routeByModel keeps the request
// path for /v1/systemone: upstream must see /v1/systemone, not
// /v1/chat/completions. /v1/rerank is the only endpoint with a path rewrite.
func TestSystemoneUpstreamPathNotRewritten(t *testing.T) {
	upstreamPath := ""

	upstreamServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		upstreamPath = r.URL.Path
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusOK)
		fmt.Fprint(w, `{"decision":"deny"}`)
	}))
	defer upstreamServer.Close()

	upstreamAddr := strings.TrimPrefix(upstreamServer.URL, "http://")

	cfg := &config.Config{
		Models: map[string]*config.ModelUpstream{
			"clef-flash": {
				Name:    "clef-flash",
				Address: upstreamAddr,
			},
		},
		Routes: make(map[string]*config.Route),
	}

	handler := New(cfg)
	defer handler.Close()

	server := httptest.NewServer(handler)
	defer server.Close()

	resp, err := http.Post(
		server.URL+"/v1/systemone",
		"application/json",
		bytes.NewReader([]byte(`{"model":"clef-flash","state":"x","questions":{}}`)),
	)
	if err != nil {
		t.Fatalf("request failed: %v", err)
	}
	defer resp.Body.Close()

	if upstreamPath != "/v1/systemone" {
		t.Errorf("expected upstream path /v1/systemone, got %s", upstreamPath)
	}
	if upstreamPath == "/v1/chat/completions" {
		t.Errorf("upstream path was rewritten to /v1/chat/completions")
	}
}