package sdk

import (
	"context"
	"errors"
	"testing"
)

// stubTool is a mock Tool used to verify the registration helpers forward to a
// Registrar.
type stubTool struct{ name string }

func (s stubTool) Name() string                                  { return s.name }
func (s stubTool) Description() string                           { return "desc " + s.name }
func (s stubTool) Parameters() (map[string]any, error)           { return map[string]any{"type": "object"}, nil }
func (s stubTool) Execute(_ context.Context, _ any) (any, error) { return "exec " + s.name, nil }

// stubSkill is a mock Skill used to verify the registration helpers forward.
type stubSkill struct{ name string }

func (s stubSkill) Name() string        { return s.name }
func (s stubSkill) Description() string { return "desc " + s.name }
func (s stubSkill) Prompt() string      { return "prompt " + s.name }
func (s stubSkill) Steps() []Step       { return []Step{{Name: "s1", Prompt: "p1"}} }
func (s stubSkill) Refs() []Ref         { return []Ref{{Name: "r1", Type: "doc"}} }
func (s stubSkill) Guardrails() []Guardrail {
	return []Guardrail{{ID: "g1", Message: "no", Enforced: true}}
}

// stubChannel is a mock Channel used to verify the registration helpers forward.
type stubChannel struct{ name string }

func (s stubChannel) Name() string                           { return s.name }
func (s stubChannel) Connect(_ context.Context) error { return nil }
func (s stubChannel) Disconnect(_ context.Context) error     { return nil }
func (s stubChannel) IsConnected() bool                      { return true }
func (s stubChannel) HealthCheck(_ context.Context) error    { return nil }

// stubRegistrar records registrations and always succeeds.
type stubRegistrar struct {
	tools    []Tool
	skills   []Skill
	channels []Channel
}

func (s *stubRegistrar) RegisterTool(t Tool) error {
	s.tools = append(s.tools, t)
	return nil
}

func (s *stubRegistrar) RegisterSkill(skl Skill) error {
	s.skills = append(s.skills, skl)
	return nil
}

func (s *stubRegistrar) RegisterChannel(c Channel) error {
	s.channels = append(s.channels, c)
	return nil
}

// errRegistrar fails every registration with the error it carries.
type errRegistrar struct{ err error }

func (e errRegistrar) RegisterTool(Tool) error       { return e.err }
func (e errRegistrar) RegisterSkill(Skill) error     { return e.err }
func (e errRegistrar) RegisterChannel(Channel) error { return e.err }

func TestRegisterTool_Forwards(t *testing.T) {
	t.Parallel()
	r := &stubRegistrar{}
	tool := stubTool{name: "calc"}
	if err := RegisterTool(r, tool); err != nil {
		t.Fatalf("RegisterTool: %v", err)
	}
	if len(r.tools) != 1 || r.tools[0] != tool {
		t.Fatalf("registered %d tools (%v), want exactly tool %v", len(r.tools), r.tools, tool)
	}
}

func TestRegisterSkill_Forwards(t *testing.T) {
	t.Parallel()
	r := &stubRegistrar{}
	skill := stubSkill{name: "review"}
	if err := RegisterSkill(r, skill); err != nil {
		t.Fatalf("RegisterSkill: %v", err)
	}
	if len(r.skills) != 1 || r.skills[0] != skill {
		t.Fatalf("registered %d skills (%v), want exactly skill %v", len(r.skills), r.skills, skill)
	}
}

func TestRegisterChannel_Forwards(t *testing.T) {
	t.Parallel()
	r := &stubRegistrar{}
	channel := stubChannel{name: "telegram"}
	if err := RegisterChannel(r, channel); err != nil {
		t.Fatalf("RegisterChannel: %v", err)
	}
	if len(r.channels) != 1 || r.channels[0] != channel {
		t.Fatalf("registered %d channels (%v), want exactly channel %v", len(r.channels), r.channels, channel)
	}
}

func TestRegisterHelpers_NilRegistrar(t *testing.T) {
	t.Parallel()
	tests := []struct {
		name string
		call func() error
	}{
		{name: "tool", call: func() error { return RegisterTool(nil, stubTool{name: "t"}) }},
		{name: "skill", call: func() error { return RegisterSkill(nil, stubSkill{name: "s"}) }},
		{name: "channel", call: func() error { return RegisterChannel(nil, stubChannel{name: "c"}) }},
	}
	for _, tt := range tests {
		tt := tt
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()
			if err := tt.call(); !errors.Is(err, ErrNilRegistrar) {
				t.Fatalf("err = %v, want ErrNilRegistrar", err)
			}
		})
	}
}

func TestRegisterHelpers_PropagateError(t *testing.T) {
	t.Parallel()
	want := errors.New("sdk: propagate error")
	tests := []struct {
		name string
		call func() error
	}{
		{name: "tool", call: func() error { return RegisterTool(errRegistrar{err: want}, stubTool{name: "t"}) }},
		{name: "skill", call: func() error { return RegisterSkill(errRegistrar{err: want}, stubSkill{name: "s"}) }},
		{name: "channel", call: func() error { return RegisterChannel(errRegistrar{err: want}, stubChannel{name: "c"}) }},
	}
	for _, tt := range tests {
		tt := tt
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()
			if err := tt.call(); !errors.Is(err, want) {
				t.Fatalf("err = %v, want %v", err, want)
			}
		})
	}
}

func TestRunConfigHooks_RunsInOrder(t *testing.T) {
	t.Parallel()
	var order []string
	hooks := []ConfigHook{
		func(_ context.Context, _ map[string]any) error { order = append(order, "a"); return nil },
		func(_ context.Context, _ map[string]any) error { order = append(order, "b"); return nil },
	}
	if err := RunConfigHooks(context.Background(), nil, hooks...); err != nil {
		t.Fatalf("RunConfigHooks: %v", err)
	}
	if len(order) != 2 || order[0] != "a" || order[1] != "b" {
		t.Fatalf("hook order = %v, want [a b]", order)
	}
}

func TestRunConfigHooks_MutatesConfig(t *testing.T) {
	t.Parallel()
	cfg := map[string]any{"a": "1"}
	hook := func(_ context.Context, c map[string]any) error { c["a"] = "2"; return nil }
	if err := RunConfigHooks(context.Background(), cfg, hook); err != nil {
		t.Fatalf("RunConfigHooks: %v", err)
	}
	if cfg["a"] != "2" {
		t.Fatalf("config a = %v, want 2", cfg["a"])
	}
}

func TestRunConfigHooks_StopsOnError(t *testing.T) {
	t.Parallel()
	hookErr := errors.New("sdk: hook error")
	ranSecond := false
	hooks := []ConfigHook{
		func(_ context.Context, _ map[string]any) error { return hookErr },
		func(_ context.Context, _ map[string]any) error { ranSecond = true; return nil },
	}
	if err := RunConfigHooks(context.Background(), nil, hooks...); !errors.Is(err, hookErr) {
		t.Fatalf("err = %v, want hookErr", err)
	}
	if ranSecond {
		t.Fatal("second hook ran after the first returned an error")
	}
}

func TestRunConfigHooks_NilHookSkipped(t *testing.T) {
	t.Parallel()
	if err := RunConfigHooks(context.Background(), nil, nil, nil); err != nil {
		t.Fatalf("RunConfigHooks(all nil): %v", err)
	}
}

func TestRunConfigHooks_ContextCanceled(t *testing.T) {
	t.Parallel()
	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	ran := false
	err := RunConfigHooks(ctx, nil, func(_ context.Context, _ map[string]any) error {
		ran = true
		return nil
	})
	if !errors.Is(err, context.Canceled) {
		t.Fatalf("err = %v, want context.Canceled", err)
	}
	if ran {
		t.Fatal("hook ran on an already-canceled context")
	}
}