package services

import (
	"context"
	"errors"
	"os"
	"testing"

	"github.com/google/uuid"
	"github.com/jmoiron/sqlx"
	_ "github.com/lib/pq"

	"mgit.msbls.de/m/paliad/internal/db"
)

// TestEventTriggerService_Trigger covers the Phase 3 Slice 6
// (t-paliad-187) entry point. The service is pure additive — it
// discovers rules via either event_type_id (Pipeline-C bridge) or
// concept_id (Pipeline-A direct FK) or both, and runs them through
// the unified Slice-4 helpers (applyDuration + evalConditionExpr +
// wireFlagsFromPriority).
//
// Live-DB test (TEST_DATABASE_URL gated) exercising:
//
//  1. Validation: missing both event_type_id + concept_id → ErrInvalidInput.
//  2. event_type_id only — parity check against EventDeadlineService.Calculate
//     (the Slice-3 legacy delegate) on a known trigger_event_id. Both code
//     paths share the unified backend post-Slice-4 so the dates must match
//     exactly.
//  3. concept_id only — returns the rules linked via deadline_rules.concept_id
//     FK. We pick any concept that has at least one active rule and assert
//     the rule count + first rule's id match.
//  4. Both together — UNION dedupe. Picking event_type_id whose
//     trigger_event_id maps to a rule that ALSO sits under the chosen
//     concept_id would let us verify dedup; today's corpus has them on
//     disjoint paths so we just verify count(event+concept) ==
//     count(event-only) + count(concept-only).
//  5. Invalid event_type_id → ErrInvalidInput (404-ish).
//  6. Invalid trigger_date format → ErrInvalidInput.
//  7. Perspective filter — drops claimant rules when perspective=defendant.
//
// Skipped when TEST_DATABASE_URL is unset, mirroring audit_service_test.go.
func TestEventTriggerService_Trigger(t *testing.T) {
	url := os.Getenv("TEST_DATABASE_URL")
	if url == "" {
		t.Skip("TEST_DATABASE_URL not set — skipping live DB test")
	}
	if err := db.ApplyMigrations(url); err != nil {
		t.Fatalf("apply migrations: %v", err)
	}
	pool, err := sqlx.Connect("postgres", url)
	if err != nil {
		t.Fatalf("connect: %v", err)
	}
	defer pool.Close()

	ctx := context.Background()

	holidays := NewHolidayService(pool)
	courts := NewCourtService(pool)
	rules := NewDeadlineRuleService(pool)
	fristen := NewFristenrechnerService(rules, holidays, courts)
	eventDeadline := NewEventDeadlineService(pool, NewDeadlineCalculator(holidays), holidays, courts, fristen)
	svc := NewEventTriggerService(pool, rules, holidays, courts)

	// -----------------------------------------------------------------
	// 1. Validation: missing both event_type_id + concept_id.
	// -----------------------------------------------------------------
	_, err = svc.Trigger(ctx, EventTriggerInput{TriggerDate: "2026-01-15"})
	if err == nil {
		t.Error("missing event_type_id + concept_id should fail; got nil")
	} else if !errors.Is(err, ErrInvalidInput) {
		t.Errorf("missing-both: want ErrInvalidInput, got %v", err)
	}

	// 6. Invalid trigger_date.
	someUUID := uuid.New()
	_, err = svc.Trigger(ctx, EventTriggerInput{
		EventTypeID: &someUUID, TriggerDate: "2026-99-99",
	})
	if err == nil {
		t.Error("invalid trigger_date should fail; got nil")
	} else if !errors.Is(err, ErrInvalidInput) {
		t.Errorf("bad-date: want ErrInvalidInput, got %v", err)
	}

	// 5. Invalid event_type_id (random UUID).
	_, err = svc.Trigger(ctx, EventTriggerInput{
		EventTypeID: &someUUID, TriggerDate: "2026-01-15",
	})
	if err == nil {
		t.Error("random event_type_id should fail; got nil")
	} else if !errors.Is(err, ErrInvalidInput) {
		t.Errorf("bad-event-type: want ErrInvalidInput, got %v", err)
	}

	// -----------------------------------------------------------------
	// Pick a live event_type that bridges to a non-empty Pipeline-C rule set.
	// -----------------------------------------------------------------
	type etRow struct {
		ID             uuid.UUID `db:"id"`
		TriggerEventID int64     `db:"trigger_event_id"`
	}
	var et etRow
	if err := pool.GetContext(ctx, &et, `
		SELECT et.id, et.trigger_event_id
		  FROM paliad.event_types et
		  JOIN paliad.deadline_rules dr ON dr.trigger_event_id = et.trigger_event_id
		 WHERE et.archived_at IS NULL
		   AND et.trigger_event_id IS NOT NULL
		   AND dr.is_active = true
		 LIMIT 1`); err != nil {
		t.Fatalf("locate live event_type with rules: %v", err)
	}

	// 2. event_type_id only — count matches the Slice-3 delegate's count.
	resp, err := svc.Trigger(ctx, EventTriggerInput{
		EventTypeID: &et.ID,
		TriggerDate: "2026-01-15",
	})
	if err != nil {
		t.Fatalf("event_type_id Trigger: %v", err)
	}
	if len(resp.Deadlines) == 0 {
		t.Fatal("event_type_id Trigger returned no deadlines — picked event_type has none?")
	}

	// Parity proxy: EventDeadlineService.Calculate on the same trigger
	// should return rules with identical names (event_deadlines.title_de
	// = deadline_rules.name post-mig 085). We compare names as multisets.
	legacy, err := eventDeadline.Calculate(ctx, et.TriggerEventID, "2026-01-15", "")
	if err != nil {
		t.Fatalf("legacy Calculate: %v", err)
	}
	if len(legacy.Deadlines) != len(resp.Deadlines) {
		t.Errorf("rule-count parity: trigger=%d, legacy=%d", len(resp.Deadlines), len(legacy.Deadlines))
	}
	legacyNames := make(map[string]int, len(legacy.Deadlines))
	for _, d := range legacy.Deadlines {
		legacyNames[d.TitleDE]++
	}
	triggerNames := make(map[string]int, len(resp.Deadlines))
	for _, d := range resp.Deadlines {
		triggerNames[d.Name]++
	}
	for name, n := range legacyNames {
		if triggerNames[name] != n {
			t.Errorf("name multiset diverges at %q: trigger=%d, legacy=%d",
				name, triggerNames[name], n)
		}
	}

	// -----------------------------------------------------------------
	// 3. concept_id only.
	// -----------------------------------------------------------------
	var conceptID uuid.UUID
	if err := pool.GetContext(ctx, &conceptID, `
		SELECT dc.id
		  FROM paliad.deadline_concepts dc
		  JOIN paliad.deadline_rules dr ON dr.concept_id = dc.id
		 WHERE dc.is_active = true
		   AND dr.is_active = true
		 GROUP BY dc.id
		 ORDER BY count(dr.id) DESC
		 LIMIT 1`); err != nil {
		t.Fatalf("locate live concept with rules: %v", err)
	}

	conceptResp, err := svc.Trigger(ctx, EventTriggerInput{
		ConceptID:   &conceptID,
		TriggerDate: "2026-01-15",
	})
	if err != nil {
		t.Fatalf("concept_id Trigger: %v", err)
	}
	if len(conceptResp.Deadlines) == 0 {
		t.Fatal("concept_id Trigger returned no deadlines")
	}
	// Spot-check: every returned rule's RuleID should be a UUID
	// (Pipeline-A rules carry uuid ids via the concept FK).
	for _, d := range conceptResp.Deadlines {
		if _, perr := uuid.Parse(d.RuleID); perr != nil {
			t.Errorf("concept rule has non-UUID RuleID=%q", d.RuleID)
		}
	}

	// -----------------------------------------------------------------
	// 4. Both together — UNION dedupe. Today's corpus has Pipeline-C
	//    rules with NULL concept_id and Pipeline-A rules with NULL
	//    trigger_event_id, so the two sets are disjoint; the UNION
	//    count equals the sum.
	// -----------------------------------------------------------------
	both, err := svc.Trigger(ctx, EventTriggerInput{
		EventTypeID: &et.ID,
		ConceptID:   &conceptID,
		TriggerDate: "2026-01-15",
	})
	if err != nil {
		t.Fatalf("both Trigger: %v", err)
	}
	if len(both.Deadlines) != len(resp.Deadlines)+len(conceptResp.Deadlines) {
		// Note: if a future seed links a concept to a Pipeline-C
		// rule (concept_id set on a trigger_event-keyed rule), the
		// dedupe branch would actually fire and the count would
		// drop. Surface the count divergence so we can adjust the
		// expectation rather than silently passing.
		t.Logf("UNION count: both=%d, event_only=%d, concept_only=%d — "+
			"non-additive count means dedupe fired (acceptable but note for review)",
			len(both.Deadlines), len(resp.Deadlines), len(conceptResp.Deadlines))
	}

	// -----------------------------------------------------------------
	// 7. Perspective filter — drops claimant rules when defendant.
	// -----------------------------------------------------------------
	// Locate a concept whose rules include both claimant + defendant
	// parties so we can verify the filter drops the opposing side.
	var partyConceptID uuid.UUID
	if err := pool.GetContext(ctx, &partyConceptID, `
		SELECT dc.id
		  FROM paliad.deadline_concepts dc
		  JOIN paliad.deadline_rules dr_c ON dr_c.concept_id = dc.id AND dr_c.primary_party = 'claimant' AND dr_c.is_active = true
		  JOIN paliad.deadline_rules dr_d ON dr_d.concept_id = dc.id AND dr_d.primary_party = 'defendant' AND dr_d.is_active = true
		 LIMIT 1`); err != nil {
		// Not every concept has both parties — accept skip when the
		// corpus lacks a mixed concept. Don't fail the test.
		t.Logf("perspective filter test skipped: no concept with mixed claimant+defendant rules (%v)", err)
		return
	}

	defendantOnly, err := svc.Trigger(ctx, EventTriggerInput{
		ConceptID:   &partyConceptID,
		TriggerDate: "2026-01-15",
		Perspective: "defendant",
	})
	if err != nil {
		t.Fatalf("defendant-perspective Trigger: %v", err)
	}
	for _, d := range defendantOnly.Deadlines {
		if d.Party == "claimant" {
			t.Errorf("defendant perspective leaked claimant rule: %s (%s)", d.Code, d.Name)
		}
	}
}