package runner

import (
	"testing"
	"time"

	"github.com/easyai/easyai-ai-gateway/apps/api/internal/clients"
	"github.com/easyai/easyai-ai-gateway/apps/api/internal/store"
)

func TestShouldRetrySameClientUsesRuntimeRetryPolicyKeywords(t *testing.T) {
	candidate := store.RuntimeModelCandidate{
		ModelRetryPolicy: map[string]any{
			"enabled":       true,
			"allowKeywords": []any{"temporary vendor blip"},
			"denyKeywords":  []any{"bad request"},
		},
	}

	if shouldRetrySameClient(candidate, &clients.ClientError{Code: "bad_request", Message: "bad request timeout", Retryable: true}) {
		t.Fatal("deny keywords should block same-client retry even when the client marks the error retryable")
	}
	if !shouldRetrySameClient(candidate, &clients.ClientError{Code: "custom_error", Message: "temporary vendor blip", Retryable: false}) {
		t.Fatal("allow keywords should allow same-client retry when the client does not mark the error retryable")
	}
}

func TestFailoverBudgetDefaults(t *testing.T) {
	candidates := make([]store.RuntimeModelCandidate, 150)
	runnerPolicy := store.RunnerPolicy{Status: "active", FailoverPolicy: map[string]any{"enabled": true}}

	if got := maxPlatformsForCandidates(candidates, runnerPolicy); got != 99 {
		t.Fatalf("default max platform budget should be 99, got %d", got)
	}
	if got := maxFailoverDurationForCandidates(candidates, runnerPolicy); got != 10*time.Minute {
		t.Fatalf("default max failover duration should be 10 minutes, got %s", got)
	}
}

func TestSingleSourceProtectionDefaultsOn(t *testing.T) {
	runnerPolicy := store.RunnerPolicy{Status: "active"}

	if !singleSourceProtectionActive([]store.RuntimeModelCandidate{{PlatformID: "only-source"}}, 99, runnerPolicy) {
		t.Fatal("single source protection should default to enabled")
	}
}

func TestSingleSourceProtectionCanBeDisabled(t *testing.T) {
	runnerPolicy := store.RunnerPolicy{
		Status:             "active",
		SingleSourcePolicy: map[string]any{"enabled": false},
	}

	if singleSourceProtectionActive([]store.RuntimeModelCandidate{{PlatformID: "only-source"}}, 99, runnerPolicy) {
		t.Fatal("single source protection should respect the global toggle")
	}
}

func TestSingleSourceProtectionUsesEffectivePlatformBudget(t *testing.T) {
	candidates := []store.RuntimeModelCandidate{
		{PlatformID: "first-source"},
		{PlatformID: "second-source"},
	}
	runnerPolicy := store.RunnerPolicy{Status: "active"}

	if !singleSourceProtectionActive(candidates, 1, runnerPolicy) {
		t.Fatal("maxPlatforms=1 should make this execution a single-source run")
	}
	if singleSourceProtectionActive(candidates, 2, runnerPolicy) {
		t.Fatal("multiple effective sources should allow disable and cooldown actions")
	}
}

func TestFailoverTimeBudgetExceeded(t *testing.T) {
	if !failoverTimeBudgetExceeded(time.Now().Add(-601*time.Second), 10*time.Minute) {
		t.Fatal("failover time budget should stop retries after the configured duration")
	}
	if failoverTimeBudgetExceeded(time.Now().Add(-590*time.Second), 10*time.Minute) {
		t.Fatal("failover time budget should allow retries before the configured duration")
	}
}

func TestLoadAvoidanceFallbackContinuesToAvoidedCandidate(t *testing.T) {
	candidates := []store.RuntimeModelCandidate{
		{PlatformID: "available-candidate"},
		{PlatformID: "avoided-full-candidate", LoadAvoided: true},
	}

	if !hasLoadAvoidanceFallback(candidates, 0, 99) {
		t.Fatal("expected non-avoided candidate to fall back to later avoided candidate")
	}
	if hasLoadAvoidanceFallback(candidates, 1, 99) {
		t.Fatal("avoided candidate should not force another load-avoidance fallback")
	}
	decision := loadAvoidanceFallbackDecision(&clients.ClientError{Code: "bad_request", StatusCode: 400, Retryable: false})
	if !decision.Retry || decision.Reason != "load_avoidance_fallback" || decision.Action != "next" {
		t.Fatalf("expected active load avoidance fallback to force next candidate, got %+v", decision)
	}
}

func TestFailoverHardStopBeatsModelOverride(t *testing.T) {
	runnerPolicy := store.RunnerPolicy{
		Status: "active",
		FailoverPolicy: map[string]any{
			"enabled":         true,
			"allowCategories": []any{"request_error"},
		},
		HardStopPolicy: map[string]any{
			"enabled":    true,
			"categories": []any{"request_error"},
		},
	}
	candidate := store.RuntimeModelCandidate{
		RuntimePolicyOverride: map[string]any{
			"failoverPolicy": map[string]any{
				"enabled":         true,
				"allowCategories": []any{"request_error"},
			},
		},
	}

	decision := failoverDecisionForCandidate(runnerPolicy, candidate, &clients.ClientError{Code: "bad_request", StatusCode: 400, Retryable: true})
	if decision.Retry || decision.Reason != "hard_stop_policy" {
		t.Fatalf("hard stop should block model-level failover override, got %+v", decision)
	}
}

func TestFailoverPolicyAllowsModelOverride(t *testing.T) {
	runnerPolicy := store.RunnerPolicy{
		Status:         "active",
		FailoverPolicy: map[string]any{"enabled": true},
		HardStopPolicy: map[string]any{"enabled": true, "categories": []any{"request_error"}},
	}
	candidate := store.RuntimeModelCandidate{
		RuntimePolicyOverride: map[string]any{
			"failoverPolicy": map[string]any{
				"allowKeywords": []any{"temporary upstream outage"},
			},
		},
	}

	decision := failoverDecisionForCandidate(runnerPolicy, candidate, &clients.ClientError{Code: "custom_error", Message: "temporary upstream outage", Retryable: false})
	if !decision.Retry || decision.Reason != "failover_allow_policy" {
		t.Fatalf("model failoverPolicy override should allow cross-platform failover, got %+v", decision)
	}
}

func TestLocalRateLimitWaitsInQueueWithoutRetryOrFailover(t *testing.T) {
	err := &localRateLimitError{
		clientErr: &clients.ClientError{Code: "rate_limit", Message: "local capacity exceeded", Retryable: true},
		cause:     &store.RateLimitExceededError{Metric: "concurrent", Retryable: true},
	}
	retryDecision := retryDecisionForCandidate(store.RuntimeModelCandidate{}, err)
	if retryDecision.Retry || retryDecision.Reason != "local_rate_limit_wait_queue" {
		t.Fatalf("local rate limit should not be same-client retry, got %+v", retryDecision)
	}

	failoverDecision := failoverDecisionForCandidate(store.RunnerPolicy{
		Status:         "active",
		FailoverPolicy: map[string]any{"enabled": true, "allowCategories": []any{"rate_limit"}},
	}, store.RuntimeModelCandidate{}, err)
	if failoverDecision.Retry || failoverDecision.Action != "queue" || failoverDecision.Reason != "local_rate_limit_wait_queue" {
		t.Fatalf("local rate limit should wait in queue without failover, got %+v", failoverDecision)
	}
}

func TestProviderAuthErrorsFailOverInsteadOfHardStop(t *testing.T) {
	runnerPolicy := store.RunnerPolicy{
		Status: "active",
		FailoverPolicy: map[string]any{
			"enabled":         true,
			"allowCategories": []any{"auth_error"},
			"allowCodes":      []any{"auth_failed", "invalid_api_key", "missing_credentials"},
			"allowStatusCodes": []any{
				401,
				403,
			},
			"actions": map[string]any{"auth_error": "disable_and_next"},
		},
		HardStopPolicy: map[string]any{
			"enabled":     true,
			"categories":  []any{"request_error", "unsupported_model", "user_permission", "insufficient_balance"},
			"codes":       []any{"bad_request", "invalid_request", "invalid_parameter", "missing_required", "permission_denied"},
			"statusCodes": []any{},
			"keywords":    []any{"invalid_parameter", "missing required", "bad request", "insufficient balance"},
		},
	}

	decision := failoverDecisionForCandidate(runnerPolicy, store.RuntimeModelCandidate{}, &clients.ClientError{Code: "auth_failed", StatusCode: 401, Retryable: false})
	if !decision.Retry || decision.Action != "disable_and_next" || decision.Reason != "failover_allow_policy" {
		t.Fatalf("provider auth failures should switch platform, got %+v", decision)
	}

	decision = failoverDecisionForCandidate(runnerPolicy, store.RuntimeModelCandidate{}, &clients.ClientError{Code: "http_400", Message: "invalid api key", StatusCode: 400, Retryable: false})
	if !decision.Retry || decision.Info.Category != "auth_error" {
		t.Fatalf("provider auth-looking 400 should switch platform, got %+v", decision)
	}
}

func TestFailoverActionRulesControlPerRuleCooldownAndDemotion(t *testing.T) {
	runnerPolicy := store.RunnerPolicy{
		Status: "active",
		FailoverPolicy: map[string]any{
			"enabled": true,
			"actionRules": []any{
				map[string]any{
					"enabled":         true,
					"categories":      []any{"rate_limit"},
					"action":          "cooldown_and_next",
					"target":          "platform",
					"cooldownSeconds": 45,
				},
				map[string]any{
					"enabled":     true,
					"keywords":    []any{"temporary overload"},
					"action":      "demote_and_next",
					"demoteSteps": 3,
				},
			},
		},
	}

	decision := failoverDecisionForCandidate(runnerPolicy, store.RuntimeModelCandidate{}, &clients.ClientError{Code: "rate_limit", StatusCode: 429, Retryable: false})
	if !decision.Retry || decision.Action != "cooldown_and_next" || decision.Target != "platform" || decision.CooldownSeconds != 45 {
		t.Fatalf("rate limit should use per-rule cooldown action, got %+v", decision)
	}

	decision = failoverDecisionForCandidate(runnerPolicy, store.RuntimeModelCandidate{}, &clients.ClientError{Code: "server_error", Message: "temporary overload from upstream", StatusCode: 503, Retryable: false})
	if !decision.Retry || decision.Action != "demote_and_next" || decision.DemoteSteps != 3 {
		t.Fatalf("keyword match should use per-rule demote action, got %+v", decision)
	}
}

func TestFailoverActionRulesCanStopAndMatchStringStatusCodes(t *testing.T) {
	runnerPolicy := store.RunnerPolicy{
		Status: "active",
		FailoverPolicy: map[string]any{
			"enabled": true,
			"actionRules": []any{
				map[string]any{
					"enabled":     true,
					"statusCodes": []any{"400"},
					"keywords":    []any{"bad request"},
					"action":      "stop",
				},
				map[string]any{
					"enabled":    true,
					"categories": []any{"request_error"},
					"action":     "next",
				},
			},
		},
	}

	decision := failoverDecisionForCandidate(runnerPolicy, store.RuntimeModelCandidate{}, &clients.ClientError{Code: "bad_request", Message: "bad request", StatusCode: 400, Retryable: true})
	if decision.Retry || decision.Action != "stop" || decision.Reason != "failover_action_rule" || decision.Match.Rule != "statusCodes" {
		t.Fatalf("first stop rule should win before later retry rules, got %+v", decision)
	}
}

func TestFailoverActionRulesKeepOrderBeforeDerivedHardStopPolicy(t *testing.T) {
	runnerPolicy := store.RunnerPolicy{
		Status: "active",
		FailoverPolicy: map[string]any{
			"enabled": true,
			"actionRules": []any{
				map[string]any{
					"enabled":  true,
					"keywords": []any{"bad request retryable"},
					"action":   "next",
				},
				map[string]any{
					"enabled":     true,
					"statusCodes": []any{400},
					"action":      "stop",
				},
			},
		},
		HardStopPolicy: map[string]any{
			"enabled":     true,
			"statusCodes": []any{400},
		},
	}

	decision := failoverDecisionForCandidate(runnerPolicy, store.RuntimeModelCandidate{}, &clients.ClientError{Code: "bad_request", Message: "bad request retryable", StatusCode: 400, Retryable: true})
	if !decision.Retry || decision.Action != "next" || decision.Match.Rule != "keywords" {
		t.Fatalf("actionRules should keep list order before derived hard stop compatibility fields, got %+v", decision)
	}
}

func TestPriorityDemotePolicyIsKeywordGatedAndHardStopSafe(t *testing.T) {
	runnerPolicy := store.RunnerPolicy{
		Status: "active",
		HardStopPolicy: map[string]any{
			"enabled":    true,
			"categories": []any{"request_error"},
		},
		PriorityDemotePolicy: map[string]any{
			"enabled":  true,
			"keywords": []any{"rate_limit"},
		},
	}

	if !shouldDemoteCandidatePriority(runnerPolicy, &clients.ClientError{Code: "rate_limit", Message: "rate_limit from upstream", Retryable: true}) {
		t.Fatal("priority demotion should be enabled only by matched policy")
	}

	if shouldDemoteCandidatePriority(runnerPolicy, &clients.ClientError{Code: "bad_request", StatusCode: 400, Retryable: true}) {
		t.Fatal("priority demotion should not run for hard-stop request errors")
	}
}

func TestPriorityDemotePolicyIsSkippedWhenFailoverActionRulesExist(t *testing.T) {
	runnerPolicy := store.RunnerPolicy{
		Status: "active",
		FailoverPolicy: map[string]any{
			"enabled": true,
			"actionRules": []any{
				map[string]any{
					"enabled":    true,
					"categories": []any{"rate_limit"},
					"action":     "demote_and_next",
				},
			},
		},
		PriorityDemotePolicy: map[string]any{
			"enabled":  true,
			"keywords": []any{"rate_limit"},
		},
	}

	decision := priorityDemoteDecisionForCandidate(runnerPolicy, &clients.ClientError{Code: "rate_limit", Message: "rate_limit from upstream", Retryable: true})
	if decision.Demote || decision.Reason != "failover_action_rules_enabled" {
		t.Fatalf("legacy priority demotion should be skipped when actionRules are active, got %+v", decision)
	}
}

func TestResolveCandidateFailureCooldownSkipsSameClientRetry(t *testing.T) {
	decision := resolveCandidateFailure(resolveCandidateFailureInput{
		RunnerPolicy: store.RunnerPolicy{
			Status: "active",
			FailoverPolicy: map[string]any{
				"enabled": true,
				"actionRules": []any{
					map[string]any{
						"statusCodes":     []any{429},
						"action":          "cooldown_and_next",
						"target":          "model",
						"cooldownSeconds": 60,
					},
				},
			},
		},
		Candidate: store.RuntimeModelCandidate{
			ModelRetryPolicy: map[string]any{"enabled": true, "maxAttempts": 3},
		},
		Err:               &clients.ClientError{Code: "resource_exhausted", StatusCode: 429, Retryable: true},
		ClientAttempt:     1,
		MaxClientAttempts: 3,
		HasNextCandidate:  true,
	})

	if decision.Route != "next" || decision.Effect != "cooldown" || decision.Target != "model" || decision.CooldownSeconds != 60 {
		t.Fatalf("429 cooldown rule should invalidate the candidate immediately, got %+v", decision)
	}
}

func TestResolveCandidateFailureDemoteRetriesBeforeNext(t *testing.T) {
	input := resolveCandidateFailureInput{
		RunnerPolicy: store.RunnerPolicy{
			Status: "active",
			FailoverPolicy: map[string]any{
				"enabled": true,
				"actionRules": []any{
					map[string]any{
						"statusCodes": []any{500},
						"action":      "demote_and_next",
						"target":      "platform",
						"demoteSteps": 2,
					},
				},
			},
		},
		Candidate: store.RuntimeModelCandidate{
			ModelRetryPolicy: map[string]any{"enabled": true, "maxAttempts": 2},
		},
		Err:               &clients.ClientError{Code: "server_error", StatusCode: 500, Retryable: true},
		ClientAttempt:     1,
		MaxClientAttempts: 2,
		HasNextCandidate:  true,
	}

	first := resolveCandidateFailure(input)
	if first.Route != "retry_same" || first.Effect != "none" {
		t.Fatalf("demotion must wait until same-client retries are exhausted, got %+v", first)
	}

	input.ClientAttempt = 2
	second := resolveCandidateFailure(input)
	if second.Route != "next" || second.Effect != "demote" || second.DemoteSteps != 2 {
		t.Fatalf("exhausted retry should demote once and rotate, got %+v", second)
	}
}

func TestResolveCandidateFailureStopsAfterDownstreamStarts(t *testing.T) {
	decision := resolveCandidateFailure(resolveCandidateFailureInput{
		RunnerPolicy: store.RunnerPolicy{
			Status: "active",
			FailoverPolicy: map[string]any{
				"enabled": true,
				"actionRules": []any{
					map[string]any{
						"categories": []any{"stream_error"},
						"action":     "next",
					},
				},
			},
		},
		Candidate:         store.RuntimeModelCandidate{ModelRetryPolicy: map[string]any{"enabled": true, "maxAttempts": 3}},
		Err:               &clients.ClientError{Code: "stream_read_error", Retryable: true},
		ClientAttempt:     1,
		MaxClientAttempts: 3,
		HasNextCandidate:  true,
		DownstreamStarted: true,
	})

	if decision.Route != "stop" || decision.Reason != "downstream_response_started" {
		t.Fatalf("stream output must prevent retries and failover, got %+v", decision)
	}
}

func TestResolveCandidateFailureLegacyPolicyPrecedence(t *testing.T) {
	candidate := store.RuntimeModelCandidate{
		DegradePolicy: map[string]any{
			"enabled":         true,
			"keywords":        []any{"resource_exhausted"},
			"cooldownSeconds": 45,
		},
	}
	decision := resolveCandidateFailure(resolveCandidateFailureInput{
		RunnerPolicy: store.RunnerPolicy{
			Status: "active",
			FailoverPolicy: map[string]any{
				"enabled": true,
				"actionRules": []any{
					map[string]any{
						"statusCodes":     []any{429},
						"action":          "cooldown_and_next",
						"target":          "platform",
						"cooldownSeconds": 90,
					},
				},
			},
		},
		Candidate:         candidate,
		Err:               &clients.ClientError{Code: "resource_exhausted", Message: "resource_exhausted", StatusCode: 429, Retryable: true},
		ClientAttempt:     1,
		MaxClientAttempts: 3,
		HasNextCandidate:  true,
	})

	if decision.Match.Policy != "degradePolicy" || decision.Target != "model" || decision.CooldownSeconds != 45 {
		t.Fatalf("legacy compatibility rule should precede global action rules, got %+v", decision)
	}
}

func TestResolveCandidateFailureUnmatchedRetryableUsesSameThenNext(t *testing.T) {
	input := resolveCandidateFailureInput{
		RunnerPolicy:      store.RunnerPolicy{Status: "active", FailoverPolicy: map[string]any{"enabled": true, "actionRules": []any{}}},
		Candidate:         store.RuntimeModelCandidate{ModelRetryPolicy: map[string]any{"enabled": true, "maxAttempts": 2}},
		Err:               &clients.ClientError{Code: "unknown_transient", Retryable: true},
		ClientAttempt:     1,
		MaxClientAttempts: 2,
		HasNextCandidate:  true,
	}

	if decision := resolveCandidateFailure(input); decision.Route != "retry_same" {
		t.Fatalf("unmatched retryable error should retry the same client first, got %+v", decision)
	}
	input.ClientAttempt = 2
	if decision := resolveCandidateFailure(input); decision.Route != "next" || decision.Effect != "none" {
		t.Fatalf("unmatched exhausted error should rotate without side effects, got %+v", decision)
	}
}