package worker

import (
	"context"
	"errors"
	"reflect"
	"testing"

	controlplanev1 "proxy-pool/gen/controlplane/v1"
	"proxy-pool/internal/config"
	"proxy-pool/internal/domain/adminstate"
)

func TestGatewayRoutingSourceBuildsOrderedRulesFromConfigurationAndAdminState(t *testing.T) {
	configuration := &config.Config{
		Routing: []config.Routing{
			{Name: "extract", Enabled: true, Purpose: "extract", Upstreams: []string{"provider-a"}, Strategy: config.Strategy{Type: "random"}, OnUnavailable: config.OnUnavailable{Action: "reject"}},
			{
				Name: "checkout", Enabled: true, Purpose: "gateway",
				Match:     config.RoutingMatch{HostRegex: "^api\\.example$", Methods: []string{"GET"}, Headers: map[string]string{"X-Tier": "gold"}},
				Upstreams: []string{"provider-a", "provider-b"}, Strategy: config.Strategy{Type: "sequential", SwitchAfterEmptyFetch: 5},
				OnUnavailable: config.OnUnavailable{Action: "reject"},
			},
			{
				Name: "fallback", Enabled: true, Purpose: "gateway", Upstreams: []string{"provider-a", "provider-c"},
				Strategy:      config.Strategy{Type: "weighted", Weights: map[string]int{"provider-a": 3, "provider-c": 7}},
				OnUnavailable: config.OnUnavailable{Action: "wait"},
			},
		},
		Upstreams: map[string]config.Upstream{
			"provider-a": {Enabled: true}, "provider-b": {Enabled: false}, "provider-c": {Enabled: true},
		},
	}
	state := adminstate.Snapshot{
		Config: &adminstate.ConfigRevision{Revision: 9},
		Upstreams: []adminstate.UpstreamState{
			{Name: "provider-a", Enabled: true}, {Name: "provider-b", Enabled: false}, {Name: "provider-c", Enabled: true},
		},
		Routings: []adminstate.RoutingState{
			{Name: "checkout", Enabled: true, Upstreams: []string{"provider-a", "provider-b"}, CurrentUpstream: "provider-a"},
			{Name: "fallback", Enabled: true, Upstreams: []string{"provider-a", "provider-c"}, CurrentUpstream: "provider-a"},
		},
	}
	source, err := NewGatewayRoutingSource(staticGatewayRoutingConfiguration{configuration: configuration, revision: 9}, staticGatewayRoutingState{snapshot: state})
	if err != nil {
		t.Fatalf("NewGatewayRoutingSource(): %v", err)
	}
	rules, err := source.Read(context.Background())
	if err != nil {
		t.Fatalf("Read(): %v", err)
	}
	if len(rules) != 2 || rules[0].GetName() != "checkout" || rules[1].GetName() != "fallback" {
		t.Fatalf("rules = %+v, want ordered gateway rules", rules)
	}
	checkout := rules[0]
	if !checkout.GetEnabled() || checkout.GetStrategy().GetType() != controlplanev1.StrategyType_STRATEGY_TYPE_SEQUENTIAL ||
		checkout.GetStrategy().GetCurrentUpstream() != "provider-a" || !reflect.DeepEqual(checkout.GetUpstreams(), []string{"provider-a"}) ||
		checkout.GetHostRegex() != "^api\\.example$" || checkout.GetHeaders()["X-Tier"] != "gold" {
		t.Fatalf("checkout rule = %+v", checkout)
	}
	fallback := rules[1]
	if !fallback.GetEnabled() || fallback.GetOnUnavailable() != controlplanev1.UnavailableAction_UNAVAILABLE_ACTION_WAIT ||
		!reflect.DeepEqual(fallback.GetUpstreams(), []string{"provider-a", "provider-c"}) ||
		!reflect.DeepEqual(fallback.GetStrategy().GetWeights(), map[string]uint32{"provider-a": 3, "provider-c": 7}) {
		t.Fatalf("fallback rule = %+v", fallback)
	}
}

func TestGatewayRoutingSourceFailsClosedWhenAdminStateDoesNotMatchConfiguration(t *testing.T) {
	configuration := &config.Config{Routing: []config.Routing{{
		Name: "gateway", Enabled: true, Purpose: "gateway", Upstreams: []string{"provider-a"},
		Strategy: config.Strategy{Type: "random"}, OnUnavailable: config.OnUnavailable{Action: "reject"},
	}}, Upstreams: map[string]config.Upstream{"provider-a": {Enabled: true}}}
	source, err := NewGatewayRoutingSource(
		staticGatewayRoutingConfiguration{configuration: configuration, revision: 5},
		staticGatewayRoutingState{snapshot: adminstate.Snapshot{Config: &adminstate.ConfigRevision{Revision: 4}}},
	)
	if err != nil {
		t.Fatalf("NewGatewayRoutingSource(): %v", err)
	}
	if _, err := source.Read(context.Background()); !errors.Is(err, ErrRoutingUnavailable) {
		t.Fatalf("Read() error = %v, want ErrRoutingUnavailable", err)
	}
}

func TestGatewayRoutingSourceDisablesSequentialRuleWhenCurrentUpstreamIsUnavailable(t *testing.T) {
	configuration := &config.Config{Routing: []config.Routing{{
		Name: "gateway", Enabled: true, Purpose: "gateway", Upstreams: []string{"provider-a", "provider-b"},
		Strategy: config.Strategy{Type: "sequential"}, OnUnavailable: config.OnUnavailable{Action: "reject"},
	}}, Upstreams: map[string]config.Upstream{
		"provider-a": {Enabled: true},
		"provider-b": {Enabled: true},
	}}
	source, err := NewGatewayRoutingSource(
		staticGatewayRoutingConfiguration{configuration: configuration, revision: 5},
		staticGatewayRoutingState{snapshot: adminstate.Snapshot{
			Config:    &adminstate.ConfigRevision{Revision: 5},
			Upstreams: []adminstate.UpstreamState{{Name: "provider-a", Enabled: false}, {Name: "provider-b", Enabled: true}},
			Routings:  []adminstate.RoutingState{{Name: "gateway", Enabled: true, CurrentUpstream: "provider-a"}},
		}},
	)
	if err != nil {
		t.Fatalf("NewGatewayRoutingSource(): %v", err)
	}
	rules, err := source.Read(context.Background())
	if err != nil {
		t.Fatalf("Read(): %v", err)
	}
	if len(rules) != 1 || rules[0].GetEnabled() || rules[0].GetStrategy().GetCurrentUpstream() != "provider-a" ||
		!reflect.DeepEqual(rules[0].GetUpstreams(), []string{"provider-b"}) {
		t.Fatalf("rules = %+v, want disabled sequential rule with provider-b remaining", rules)
	}
}

type staticGatewayRoutingConfiguration struct {
	configuration *config.Config
	revision      uint64
}

func (reader staticGatewayRoutingConfiguration) Snapshot() (*config.Config, uint64) {
	return reader.configuration, reader.revision
}

type staticGatewayRoutingState struct {
	snapshot adminstate.Snapshot
	err      error
}

func (reader staticGatewayRoutingState) Snapshot(context.Context) (adminstate.Snapshot, error) {
	return reader.snapshot, reader.err
}