package httputil

import (
	"context"
	"net/http"
	"net/http/httptest"
	"reflect"
	"strings"
	"testing"
	"time"

	"github.com/go-chi/chi/v5"
	"github.com/google/uuid"

	"code.nochebuena.dev/einherjar/core/valid"
)

// withPath attaches a chi route context carrying the given key/value path params,
// mirroring what the router injects before a handler runs.
func withPath(r *http.Request, kv ...string) *http.Request {
	rctx := chi.NewRouteContext()
	for i := 0; i+1 < len(kv); i += 2 {
		rctx.URLParams.Add(kv[i], kv[i+1])
	}
	return r.WithContext(context.WithValue(r.Context(), chi.RouteCtxKey, rctx))
}

// AC1 — Bind fills path, query and json fields on one struct.
func TestBind_FillsAllThreeSources(t *testing.T) {
	type req struct {
		RoleID string `path:"roleID"`
		Page   int    `query:"page"`
		Name   string `json:"name"`
	}
	var got req
	h := Bind(valid.New(), discardLogger(), func(_ context.Context, r req) (tRes, error) {
		got = r
		return tRes{ID: r.RoleID}, nil
	})
	rec := httptest.NewRecorder()
	r := withPath(httptest.NewRequest(http.MethodPatch, "/roles/abc?page=7", strings.NewReader(`{"name":"turno"}`)), "roleID", "abc")
	h(rec, r)

	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200 (body: %s)", rec.Code, rec.Body.String())
	}
	if got.RoleID != "abc" || got.Page != 7 || got.Name != "turno" {
		t.Fatalf("bound = %+v, want {abc 7 turno}", got)
	}
}

// AC1 + AC3 — BindEmpty writes a body-less success and needs no request body.
func TestBindEmpty_PathOnly_NoBody(t *testing.T) {
	type req struct {
		RoleID string `path:"roleID"`
	}
	called := ""
	h := BindEmpty(valid.New(), discardLogger(), func(_ context.Context, r req) error {
		called = r.RoleID
		return nil
	})
	rec := httptest.NewRecorder()
	// DELETE with a nil body — the HandleEmpty io.EOF trap must not fire.
	h(rec, withPath(httptest.NewRequest(http.MethodDelete, "/roles/xyz", nil), "roleID", "xyz"))

	if rec.Code != http.StatusNoContent {
		t.Fatalf("status = %d, want 204", rec.Code)
	}
	if rec.Body.Len() != 0 {
		t.Errorf("expected empty body, got %q", rec.Body.String())
	}
	if called != "xyz" {
		t.Errorf("path not bound: got %q", called)
	}
}

// AC3 — a bodiless GET succeeds through Bind (query only, no io.EOF).
func TestBind_NoBody_QueryOnly(t *testing.T) {
	type req struct {
		Q string `query:"q"`
	}
	h := Bind(valid.New(), discardLogger(), func(_ context.Context, r req) (tRes, error) {
		return tRes{ID: r.Q}, nil
	})
	rec := httptest.NewRecorder()
	h(rec, httptest.NewRequest(http.MethodGet, "/roles?q=hola", nil))
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200 (body: %s)", rec.Code, rec.Body.String())
	}
	if got := strings.TrimSpace(rec.Body.String()); got != `{"id":"hola"}` {
		t.Errorf("body = %q", got)
	}
}

// AC2 — a field with two source tags fails at wiring (Bind panics at registration).
func TestBind_TwoSourceTags_PanicsAtWiring(t *testing.T) {
	type req struct {
		Bad string `path:"id" query:"id"`
	}
	defer func() {
		if recover() == nil {
			t.Fatal("Bind did not panic on a two-source-tag field")
		}
	}()
	_ = Bind(valid.New(), discardLogger(), func(_ context.Context, _ req) (tRes, error) {
		return tRes{}, nil
	})
}

// AC2 (companion) — an unsupported field type and a bad default also fail at wiring.
func TestBind_UnsupportedType_PanicsAtWiring(t *testing.T) {
	type req struct {
		Ch chan int `query:"ch"`
	}
	defer func() {
		if recover() == nil {
			t.Fatal("Bind did not panic on an unsupported field type")
		}
	}()
	_ = Bind(valid.New(), discardLogger(), func(_ context.Context, _ req) (tRes, error) { return tRes{}, nil })
}

func TestBind_BadDefault_PanicsAtWiring(t *testing.T) {
	type req struct {
		Page int `query:"page" default:"not-a-number"`
	}
	defer func() {
		if recover() == nil {
			t.Fatal("Bind did not panic on an invalid default tag")
		}
	}()
	_ = Bind(valid.New(), discardLogger(), func(_ context.Context, _ req) (tRes, error) { return tRes{}, nil })
}

// AC4 — uuid.UUID and time.Time bind from path and query via TextUnmarshaler.
func TestBind_TextUnmarshaler_UUIDAndTime(t *testing.T) {
	type req struct {
		ID   uuid.UUID `path:"id"`
		From time.Time `query:"from"`
	}
	id := uuid.New()
	var got req
	h := Bind(valid.New(), discardLogger(), func(_ context.Context, r req) (tRes, error) {
		got = r
		return tRes{ID: r.ID.String()}, nil
	})
	rec := httptest.NewRecorder()
	r := withPath(httptest.NewRequest(http.MethodGet, "/x/"+id.String()+"?from=2026-01-02T03:04:05Z", nil), "id", id.String())
	h(rec, r)

	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200 (body: %s)", rec.Code, rec.Body.String())
	}
	if got.ID != id {
		t.Errorf("uuid = %s, want %s", got.ID, id)
	}
	if !got.From.Equal(time.Date(2026, 1, 2, 3, 4, 5, 0, time.UTC)) {
		t.Errorf("time = %s, want 2026-01-02T03:04:05Z", got.From)
	}
}

// AC5 — a malformed value answers 400 and names the parameter, never 500.
func TestBind_MalformedParam_400WithName(t *testing.T) {
	type req struct {
		Page int `query:"page"`
	}
	h := Bind(valid.New(), discardLogger(), func(_ context.Context, _ req) (tRes, error) {
		return tRes{}, nil
	})
	rec := httptest.NewRecorder()
	h(rec, httptest.NewRequest(http.MethodGet, "/roles?page=abc", nil))

	if rec.Code != http.StatusBadRequest {
		t.Fatalf("status = %d, want 400", rec.Code)
	}
	if !strings.Contains(rec.Body.String(), "page") {
		t.Errorf("error body %q does not name the parameter", rec.Body.String())
	}
}

// AC4/AC5 — a malformed uuid path parameter is also a 400, not a 500.
func TestBind_MalformedUUID_400(t *testing.T) {
	type req struct {
		ID uuid.UUID `path:"id"`
	}
	h := Bind(valid.New(), discardLogger(), func(_ context.Context, _ req) (tRes, error) {
		return tRes{}, nil
	})
	rec := httptest.NewRecorder()
	h(rec, withPath(httptest.NewRequest(http.MethodGet, "/x/nope", nil), "id", "nope"))
	if rec.Code != http.StatusBadRequest {
		t.Fatalf("status = %d, want 400", rec.Code)
	}
}

// AC6 — default applies when the parameter is absent, and NOT when present-and-empty.
func TestBind_Default_AbsentOnly(t *testing.T) {
	type req struct {
		Page int    `query:"page" default:"1"`
		Q    string `query:"q"    default:"all"`
	}

	// Absent → defaults applied.
	var absent req
	h := Bind(valid.New(), discardLogger(), func(_ context.Context, r req) (tRes, error) {
		absent = r
		return tRes{}, nil
	})
	h(httptest.NewRecorder(), httptest.NewRequest(http.MethodGet, "/roles", nil))
	if absent.Page != 1 || absent.Q != "all" {
		t.Fatalf("absent defaults = %+v, want {1 all}", absent)
	}

	// Present-but-empty (?q=) → the caller is clearing the filter; default must NOT win.
	var present req
	h2 := Bind(valid.New(), discardLogger(), func(_ context.Context, r req) (tRes, error) {
		present = r
		return tRes{}, nil
	})
	rec := httptest.NewRecorder()
	h2(rec, httptest.NewRequest(http.MethodGet, "/roles?q=", nil))
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200 (body: %s)", rec.Code, rec.Body.String())
	}
	if present.Q != "" {
		t.Errorf("present-empty q = %q, want \"\" (default must not override)", present.Q)
	}
}

// AC7 — repeated query parameters bind to a slice; a comma inside a scalar survives.
func TestBind_RepeatedQuery_Slice(t *testing.T) {
	type req struct {
		Kind []string `query:"kind"`
		Q    string   `query:"q"`
	}
	var got req
	h := Bind(valid.New(), discardLogger(), func(_ context.Context, r req) (tRes, error) {
		got = r
		return tRes{}, nil
	})
	rec := httptest.NewRecorder()
	h(rec, httptest.NewRequest(http.MethodGet, "/x?kind=POS&kind=KDS&q=a,b,c", nil))

	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200 (body: %s)", rec.Code, rec.Body.String())
	}
	if len(got.Kind) != 2 || got.Kind[0] != "POS" || got.Kind[1] != "KDS" {
		t.Errorf("kind = %v, want [POS KDS]", got.Kind)
	}
	if got.Q != "a,b,c" {
		t.Errorf("q = %q, want verbatim a,b,c (no comma splitting)", got.Q)
	}
}

// AC7 (companion) — a typed slice ([]uuid.UUID) binds each repeated value.
func TestBind_RepeatedQuery_TypedSlice(t *testing.T) {
	type req struct {
		IDs []uuid.UUID `query:"id"`
	}
	a, b := uuid.New(), uuid.New()
	var got req
	h := Bind(valid.New(), discardLogger(), func(_ context.Context, r req) (tRes, error) {
		got = r
		return tRes{}, nil
	})
	rec := httptest.NewRecorder()
	h(rec, httptest.NewRequest(http.MethodGet, "/x?id="+a.String()+"&id="+b.String(), nil))
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200 (body: %s)", rec.Code, rec.Body.String())
	}
	if len(got.IDs) != 2 || got.IDs[0] != a || got.IDs[1] != b {
		t.Errorf("ids = %v, want [%s %s]", got.IDs, a, b)
	}
}

// WithStatus composes with Bind exactly as with Handle (201 on create).
func TestBind_WithStatus(t *testing.T) {
	type req struct {
		Name string `json:"name" validate:"required"`
	}
	h := Bind(valid.New(), discardLogger(), func(_ context.Context, r req) (tRes, error) {
		return tRes{ID: r.Name}, nil
	}, WithStatus(http.StatusCreated))
	rec := httptest.NewRecorder()
	h(rec, httptest.NewRequest(http.MethodPost, "/roles", strings.NewReader(`{"name":"cajero"}`)))
	if rec.Code != http.StatusCreated {
		t.Fatalf("status = %d, want 201", rec.Code)
	}
}

// Validation runs on the assembled struct — a query bound value is validated too.
func TestBind_ValidatesAssembledStruct(t *testing.T) {
	type req struct {
		PerPage int `query:"per_page" default:"50" validate:"min=1,max=200"`
	}
	h := Bind(valid.New(), discardLogger(), func(_ context.Context, _ req) (tRes, error) {
		return tRes{}, nil
	})
	rec := httptest.NewRecorder()
	h(rec, httptest.NewRequest(http.MethodGet, "/roles?per_page=99999", nil))
	if rec.Code != http.StatusBadRequest {
		t.Fatalf("status = %d, want 400 (per_page over max should fail validation)", rec.Code)
	}
}

// AC9 — the per-type plan is reflected once and cached (same pointer across calls).
func TestBind_PlanCachedPerType(t *testing.T) {
	type req struct {
		A string `query:"a"`
		B int    `query:"b"`
	}
	rt := reflect.TypeOf((*req)(nil)).Elem()
	if planFor(rt) != planFor(rt) {
		t.Fatal("planFor returned a different plan for the same type — cache not effective")
	}
}

// AC9 — per-request work does not re-reflect the type; the plan metadata is
// parsed once and reused. Run with -benchmem to see allocations stay flat
// regardless of how many tagged fields the struct declares.
func BenchmarkBind_ManyFields(b *testing.B) {
	type req struct {
		ID      uuid.UUID `path:"id"`
		Page    int       `query:"page"    default:"1"`
		PerPage int       `query:"per_page" default:"50"`
		Q       string    `query:"q"`
		Sort    string    `query:"sort"    default:"name"`
		Order   string    `query:"order"   default:"asc"`
		Kind    []string  `query:"kind"`
	}
	id := uuid.New()
	h := Bind(valid.New(), discardLogger(), func(_ context.Context, _ req) (tRes, error) {
		return tRes{}, nil
	})
	target := "/x/" + id.String() + "?page=2&per_page=25&q=turno&sort=name&order=desc&kind=POS&kind=KDS"

	b.ReportAllocs()
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		rec := httptest.NewRecorder()
		h(rec, withPath(httptest.NewRequest(http.MethodGet, target, nil), "id", id.String()))
	}
}