package api

import (
	"encoding/json"
	"net/http"
	"strconv"
	"testing"

	"github.com/gin-gonic/gin"
)

// registerAndCookie creates a user via the API and returns its session cookie.
func registerAndCookie(t *testing.T, r *gin.Engine, email string) *http.Cookie {
	t.Helper()
	w := doJSON(t, r, http.MethodPost, "/api/v1/auth/register",
		map[string]string{"email": email, "displayName": email, "password": "password123"}, nil)
	if w.Code != http.StatusOK {
		t.Fatalf("register %s: status %d, body %s", email, w.Code, w.Body.String())
	}
	return sessionCookieFrom(t, w)
}

// decodeMap unmarshals any JSON object response into a generic map.
func decodeMap(t *testing.T, body []byte) map[string]any {
	t.Helper()
	var m map[string]any
	if err := json.Unmarshal(body, &m); err != nil {
		t.Fatalf("decode json object: %v (body %s)", err, body)
	}
	return m
}

func TestGardenCRUDFlow(t *testing.T) {
	r := authEngine(t, localCfg())
	cookie := registerAndCookie(t, r, "a@example.com")

	// Create (defaults applied) → 201.
	w := doJSON(t, r, http.MethodPost, "/api/v1/gardens", map[string]any{"name": "Backyard"}, cookie)
	if w.Code != http.StatusCreated {
		t.Fatalf("create status = %d, body %s", w.Code, w.Body.String())
	}
	created := decodeMap(t, w.Body.Bytes())
	id := int64(created["id"].(float64))
	if created["widthCm"].(float64) != 1000 || created["unitPref"].(string) != "metric" {
		t.Errorf("defaults not applied: %+v", created)
	}

	// List → array with one garden.
	w = doJSON(t, r, http.MethodGet, "/api/v1/gardens", nil, cookie)
	if w.Code != http.StatusOK {
		t.Fatalf("list status = %d", w.Code)
	}
	var list []map[string]any
	if err := json.Unmarshal(w.Body.Bytes(), &list); err != nil {
		t.Fatalf("decode list: %v (body %s)", err, w.Body.String())
	}
	if len(list) != 1 {
		t.Errorf("list len = %d, want 1", len(list))
	}

	// Get → 200.
	w = doJSON(t, r, http.MethodGet, gardenPath(id), nil, cookie)
	if w.Code != http.StatusOK {
		t.Fatalf("get status = %d", w.Code)
	}

	// Patch with the current version → 200, version bumped.
	w = doJSON(t, r, http.MethodPatch, gardenPath(id),
		map[string]any{"name": "Front", "widthCm": 200, "heightCm": 400, "unitPref": "imperial", "version": 1}, cookie)
	if w.Code != http.StatusOK {
		t.Fatalf("patch status = %d, body %s", w.Code, w.Body.String())
	}
	patched := decodeMap(t, w.Body.Bytes())
	if patched["name"].(string) != "Front" || patched["version"].(float64) != 2 {
		t.Errorf("patch didn't persist/bump: %+v", patched)
	}

	// Delete → 204, then get → 404.
	w = doJSON(t, r, http.MethodDelete, gardenPath(id), nil, cookie)
	if w.Code != http.StatusNoContent {
		t.Fatalf("delete status = %d", w.Code)
	}
	w = doJSON(t, r, http.MethodGet, gardenPath(id), nil, cookie)
	if w.Code != http.StatusNotFound {
		t.Errorf("get after delete = %d, want 404", w.Code)
	}
}

func TestGardenVersionConflictEnvelope(t *testing.T) {
	r := authEngine(t, localCfg())
	cookie := registerAndCookie(t, r, "a@example.com")

	w := doJSON(t, r, http.MethodPost, "/api/v1/gardens", map[string]any{"name": "Yard"}, cookie)
	id := int64(decodeMap(t, w.Body.Bytes())["id"].(float64))

	body := map[string]any{"name": "Yard2", "widthCm": 1000, "heightCm": 1000, "unitPref": "metric", "version": 1}
	// First patch at version 1 succeeds (→ version 2).
	if w := doJSON(t, r, http.MethodPatch, gardenPath(id), body, cookie); w.Code != http.StatusOK {
		t.Fatalf("first patch status = %d", w.Code)
	}
	// Second patch still at version 1 conflicts.
	w = doJSON(t, r, http.MethodPatch, gardenPath(id), body, cookie)
	if w.Code != http.StatusConflict {
		t.Fatalf("stale patch status = %d, want 409", w.Code)
	}
	var env struct {
		Error   struct{ Code string } `json:"error"`
		Current map[string]any        `json:"current"`
	}
	if err := json.Unmarshal(w.Body.Bytes(), &env); err != nil {
		t.Fatalf("decode conflict envelope: %v (body %s)", err, w.Body.String())
	}
	if env.Error.Code != "VERSION_CONFLICT" {
		t.Errorf("error code = %q, want VERSION_CONFLICT", env.Error.Code)
	}
	if env.Current == nil || env.Current["version"].(float64) != 2 {
		t.Errorf("conflict body missing current row at version 2: %+v", env.Current)
	}
}

func TestGardenCrossUserIsNotFound(t *testing.T) {
	r := authEngine(t, localCfg())
	alice := registerAndCookie(t, r, "alice@example.com")
	bob := registerAndCookie(t, r, "bob@example.com")

	w := doJSON(t, r, http.MethodPost, "/api/v1/gardens", map[string]any{"name": "Alice's"}, alice)
	id := int64(decodeMap(t, w.Body.Bytes())["id"].(float64))

	// Bob sees a 404 (existence masked), not a 403.
	if w := doJSON(t, r, http.MethodGet, gardenPath(id), nil, bob); w.Code != http.StatusNotFound {
		t.Errorf("bob get = %d, want 404", w.Code)
	}
	if w := doJSON(t, r, http.MethodDelete, gardenPath(id), nil, bob); w.Code != http.StatusNotFound {
		t.Errorf("bob delete = %d, want 404", w.Code)
	}
	// Bob's own list is empty.
	w = doJSON(t, r, http.MethodGet, "/api/v1/gardens", nil, bob)
	if w.Body.String() != "[]" {
		t.Errorf("bob list = %s, want []", w.Body.String())
	}
}

func TestGardenRequiresAuth(t *testing.T) {
	r := authEngine(t, localCfg())
	if w := doJSON(t, r, http.MethodGet, "/api/v1/gardens", nil, nil); w.Code != http.StatusUnauthorized {
		t.Errorf("unauthenticated list = %d, want 401", w.Code)
	}
	if w := doJSON(t, r, http.MethodPost, "/api/v1/gardens", map[string]any{"name": "X"}, nil); w.Code != http.StatusUnauthorized {
		t.Errorf("unauthenticated create = %d, want 401", w.Code)
	}
}

func TestGardenCreateValidation(t *testing.T) {
	r := authEngine(t, localCfg())
	cookie := registerAndCookie(t, r, "a@example.com")
	// Missing name → 400.
	if w := doJSON(t, r, http.MethodPost, "/api/v1/gardens", map[string]any{"widthCm": 100}, cookie); w.Code != http.StatusBadRequest {
		t.Errorf("no-name create = %d, want 400", w.Code)
	}
	// Bad id path → 400.
	if w := doJSON(t, r, http.MethodGet, "/api/v1/gardens/not-a-number", nil, cookie); w.Code != http.StatusBadRequest {
		t.Errorf("bad id get = %d, want 400", w.Code)
	}
}

func TestGardenUpdateRejectsBadVersion(t *testing.T) {
	r := authEngine(t, localCfg())
	cookie := registerAndCookie(t, r, "a@example.com")
	w := doJSON(t, r, http.MethodPost, "/api/v1/gardens", map[string]any{"name": "Yard"}, cookie)
	id := int64(decodeMap(t, w.Body.Bytes())["id"].(float64))

	// A negative (or zero) version is invalid input (400), not a version conflict.
	for _, v := range []int{0, -1} {
		body := map[string]any{"name": "x", "widthCm": 100, "heightCm": 100, "unitPref": "metric", "version": v}
		if w := doJSON(t, r, http.MethodPatch, gardenPath(id), body, cookie); w.Code != http.StatusBadRequest {
			t.Errorf("version %d patch = %d, want 400", v, w.Code)
		}
	}
}

func gardenPath(id int64) string {
	return "/api/v1/gardens/" + strconv.FormatInt(id, 10)
}