package seeder_test

import (
	"context"
	"testing"
	"time"

	"github.com/krow/krow-backend/go-api/internal/seeder"
	"github.com/krow/krow-backend/go-api/internal/testutil"
)

// tableFor maps the fixture's entity names onto their tables, so the counts
// asserted below come from the frontend's own data rather than from literals.
var tableFor = map[string]string{
	"JobPosting": "job_postings", "JobApplication": "job_applications",
	"AIInterview": "ai_interviews", "Staff": "staff", "WorkerProfile": "worker_profiles",
	"Course": "courses", "Badge": "badges", "LearningPath": "learning_paths",
	"Certification": "certifications", "RoleCategory": "role_categories",
	"UserActivity": "user_activity", "Evidence": "evidence", "Assignment": "assignments",
}

func count(t *testing.T, h *testutil.Harness, table string) int {
	t.Helper()
	var n int
	if err := h.Pool.QueryRow(context.Background(), "SELECT count(*) FROM "+table).Scan(&n); err != nil {
		t.Fatalf("count %s: %v", table, err)
	}
	return n
}

// TestSeedMatchesFixtureCounts checks every entity against the fixture rather
// than against a hardcoded headline number.
func TestSeedMatchesFixtureCounts(t *testing.T) {
	h := testutil.New(t)
	fx := testutil.Fixture(t)

	for entity, table := range tableFor {
		want := len(fx.Entities[entity])
		if got := count(t, h, table); got != want {
			t.Errorf("%s: seeded %d rows, fixture has %d", table, got, want)
		}
	}
}

// TestSeedRegressionAnchors pins the figures the demo dataset is built to
// produce. These are verified against the source, not assumed: the prompt's
// "6 postings / 22 applications" is 6 *active* postings and 24 applications.
func TestSeedRegressionAnchors(t *testing.T) {
	h := testutil.New(t)
	ctx := context.Background()

	var active int
	if err := h.Pool.QueryRow(ctx,
		"SELECT count(*) FROM job_postings WHERE status = 'active'").Scan(&active); err != nil {
		t.Fatal(err)
	}
	if active != 6 {
		t.Errorf("active postings = %d, want 6", active)
	}
	if total := count(t, h, "job_postings"); total != 8 {
		t.Errorf("job postings = %d, want 8 (6 active, 1 paused, 1 closed)", total)
	}
	if total := count(t, h, "job_applications"); total != 24 {
		t.Errorf("applications = %d, want 24", total)
	}

	var scored int
	var avgScored float64
	if err := h.Pool.QueryRow(ctx,
		"SELECT count(*), coalesce(avg(ai_score), 0) FROM job_applications WHERE ai_score > 0").
		Scan(&scored, &avgScored); err != nil {
		t.Fatal(err)
	}
	if scored != 9 {
		t.Errorf("scored applications = %d, want 9", scored)
	}
	if avgScored < 75.95 || avgScored > 76.05 {
		t.Errorf("average scored ai_score = %.2f, want 76.0", avgScored)
	}

	var hires int
	var avgHire float64
	if err := h.Pool.QueryRow(ctx,
		"SELECT count(*), coalesce(avg(ai_score), 0) FROM staff").Scan(&hires, &avgHire); err != nil {
		t.Fatal(err)
	}
	if hires != 3 {
		t.Errorf("hires = %d, want 3", hires)
	}
	if avgHire < 94.0 || avgHire > 94.5 {
		t.Errorf("average hire ai_score = %.2f, want ~94.3", avgHire)
	}
}

// TestSeedPreservesSourceValues compares stored rows field-by-field against the
// fixture, rather than trusting that the counts lining up means the data did.
func TestSeedPreservesSourceValues(t *testing.T) {
	h := testutil.New(t)
	fx := testutil.Fixture(t)
	ctx := context.Background()

	for _, want := range fx.Entities["JobPosting"] {
		legacy := want["id"].(string)
		var title, status, company, roleCategory, createdDate string
		var payMin, payMax int
		err := h.Pool.QueryRow(ctx, `
			SELECT title, status::text, company, role_category, pay_range_min, pay_range_max,
			       to_char(created_date AT TIME ZONE 'UTC', 'YYYY-MM-DD"T"HH24:MI:SS.MS"Z"')
			  FROM job_postings WHERE legacy_id = $1`, legacy).
			Scan(&title, &status, &company, &roleCategory, &payMin, &payMax, &createdDate)
		if err != nil {
			t.Fatalf("%s: %v", legacy, err)
		}
		if title != want["title"] {
			t.Errorf("%s title = %q, want %q", legacy, title, want["title"])
		}
		if status != want["status"] {
			t.Errorf("%s status = %q, want %q", legacy, status, want["status"])
		}
		if createdDate != want["created_date"] {
			t.Errorf("%s created_date = %q, want %q", legacy, createdDate, want["created_date"])
		}
		if v, ok := want["pay_range_min"].(float64); ok && payMin != int(v) {
			t.Errorf("%s pay_range_min = %d, want %d", legacy, payMin, int(v))
		}
		if v, ok := want["pay_range_max"].(float64); ok && payMax != int(v) {
			t.Errorf("%s pay_range_max = %d, want %d", legacy, payMax, int(v))
		}
	}

	// Applications carry updated_date in the source, and the gap from
	// created_date is what buildHires reads as time-to-hire.
	for _, want := range fx.Entities["JobApplication"] {
		legacy := want["id"].(string)
		var name, email, status, created, updated string
		var score int
		err := h.Pool.QueryRow(ctx, `
			SELECT applicant_name, email::text, status::text, ai_score,
			       to_char(created_date AT TIME ZONE 'UTC', 'YYYY-MM-DD"T"HH24:MI:SS.MS"Z"'),
			       to_char(updated_date AT TIME ZONE 'UTC', 'YYYY-MM-DD"T"HH24:MI:SS.MS"Z"')
			  FROM job_applications WHERE legacy_id = $1`, legacy).
			Scan(&name, &email, &status, &score, &created, &updated)
		if err != nil {
			t.Fatalf("%s: %v", legacy, err)
		}
		if name != want["applicant_name"] {
			t.Errorf("%s applicant_name = %q, want %q", legacy, name, want["applicant_name"])
		}
		if status != want["status"] {
			t.Errorf("%s status = %q, want %q", legacy, status, want["status"])
		}
		if created != want["created_date"] {
			t.Errorf("%s created_date = %q, want %q", legacy, created, want["created_date"])
		}
		if updated != want["updated_date"] {
			t.Errorf("%s updated_date = %q, want %q", legacy, updated, want["updated_date"])
		}
		if v, ok := want["ai_score"].(float64); ok && score != int(v) {
			t.Errorf("%s ai_score = %d, want %d", legacy, score, int(v))
		}
	}
}

// TestSeedIsIdempotent runs the seeder a second time over an already-seeded
// database and expects every count and every id to be unchanged.
func TestSeedIsIdempotent(t *testing.T) {
	h := testutil.New(t)
	fx := testutil.Fixture(t)
	ctx := context.Background()

	before := map[string]int{}
	for _, table := range tableFor {
		before[table] = count(t, h, table)
	}
	var idsBefore string
	if err := h.Pool.QueryRow(ctx,
		"SELECT coalesce(string_agg(id::text, ',' ORDER BY id), '') FROM job_applications").
		Scan(&idsBefore); err != nil {
		t.Fatal(err)
	}

	if _, err := seeder.New(h.Pool, fx, h.Now).Run(ctx); err != nil {
		t.Fatalf("second seed: %v", err)
	}

	for _, table := range tableFor {
		if got := count(t, h, table); got != before[table] {
			t.Errorf("%s: %d rows after re-seed, %d before — the seeder duplicated rows",
				table, got, before[table])
		}
	}
	var idsAfter string
	if err := h.Pool.QueryRow(ctx,
		"SELECT coalesce(string_agg(id::text, ',' ORDER BY id), '') FROM job_applications").
		Scan(&idsAfter); err != nil {
		t.Fatal(err)
	}
	if idsAfter != idsBefore {
		t.Error("application ids changed across a re-seed; keys are not deterministic")
	}
}

// TestSeedRelationships checks that every reference was rewritten to a real row.
func TestSeedRelationships(t *testing.T) {
	h := testutil.New(t)
	ctx := context.Background()

	dangling := []struct{ name, query string }{
		{"applications without a posting",
			`SELECT count(*) FROM job_applications a
			   LEFT JOIN job_postings p ON p.id = a.job_posting_id WHERE p.id IS NULL`},
		{"interviews without an application",
			`SELECT count(*) FROM ai_interviews i
			   LEFT JOIN job_applications a ON a.id = i.application_id WHERE a.id IS NULL`},
		{"staff without an application",
			`SELECT count(*) FROM staff s LEFT JOIN job_applications a ON a.id = s.application_id
			  WHERE s.application_id IS NOT NULL AND a.id IS NULL`},
		{"shifts without staff",
			`SELECT count(*) FROM shift_records r LEFT JOIN staff s ON s.id = r.staff_id
			  WHERE r.staff_id IS NOT NULL AND s.id IS NULL`},
		{"evidence without a course",
			`SELECT count(*) FROM evidence e LEFT JOIN courses c ON c.id = e.course_id
			  WHERE e.course_id IS NOT NULL AND c.id IS NULL`},
	}
	for _, d := range dangling {
		var n int
		if err := h.Pool.QueryRow(ctx, d.query).Scan(&n); err != nil {
			t.Fatalf("%s: %v", d.name, err)
		}
		if n != 0 {
			t.Errorf("%s: %d", d.name, n)
		}
	}

	// interview_id is a soft reference on purpose: the source contains one
	// dangling value (app_devon -> int_devon), and preserving it is the point.
	var set, resolve int
	if err := h.Pool.QueryRow(ctx,
		`SELECT (SELECT count(*) FROM job_applications WHERE interview_id IS NOT NULL),
		        (SELECT count(*) FROM job_applications a JOIN ai_interviews i ON i.id = a.interview_id)`).
		Scan(&set, &resolve); err != nil {
		t.Fatal(err)
	}
	if set != 5 {
		t.Errorf("applications carrying interview_id = %d, want 5", set)
	}
	if resolve != 4 {
		t.Errorf("resolvable interview_id = %d, want 4 (int_devon dangles in the source)", resolve)
	}
}

// TestSeedOrganizationScope checks every seeded row belongs to the development
// organization, so organization scoping has something real to filter on.
func TestSeedOrganizationScope(t *testing.T) {
	h := testutil.New(t)
	ctx := context.Background()
	for _, table := range tableFor {
		var wrong int
		if err := h.Pool.QueryRow(ctx,
			"SELECT count(*) FROM "+table+" WHERE org_id IS DISTINCT FROM $1::uuid", h.OrgID).
			Scan(&wrong); err != nil {
			t.Fatalf("%s: %v", table, err)
		}
		if wrong != 0 {
			t.Errorf("%s: %d rows outside the development organization", table, wrong)
		}
	}
}

// TestDeterministicUUID pins the key derivation: the same source id must always
// produce the same key, or a re-seed would duplicate every row.
func TestDeterministicUUID(t *testing.T) {
	a := seeder.DeterministicUUID("JobPosting:job_chef")
	b := seeder.DeterministicUUID("JobPosting:job_chef")
	if a != b {
		t.Fatalf("not deterministic: %s != %s", a, b)
	}
	if c := seeder.DeterministicUUID("JobPosting:job_security"); c == a {
		t.Fatal("distinct source ids produced the same key")
	}
	if len(a) != 36 || a[14] != '5' {
		t.Errorf("expected a v5 UUID, got %q", a)
	}
}

// TestSeedDoesNotDependOnWallClock: seeding twice with the same anchor must
// produce identical shift records.
func TestSeedShiftsStableForAnchor(t *testing.T) {
	anchor := time.Date(2026, 8, 21, 15, 0, 0, 0, time.Local)
	a := seeder.BuildShifts(anchor)
	b := seeder.BuildShifts(anchor)
	if len(a) != len(b) {
		t.Fatalf("shift count differs between runs: %d vs %d", len(a), len(b))
	}
	for i := range a {
		if a[i]["id"] != b[i]["id"] || a[i]["created_date"] != b[i]["created_date"] {
			t.Fatalf("shift %d differs between runs", i)
		}
	}
}