package bm_test

import (
	"database/sql"
	"testing"

	"git.golem15.com/jakub/sm-bm-plugin/updates"
	"gorm.io/gorm"
)

// TestMoveZjazdTagsAgainstDatabase pins the data behaviour of the one-way
// zjazd migration (D-12): a material with no meeting gets the meeting its
// zjazd-N tag names (the lowest when it has several), an existing meeting
// is kept, a tag naming a missing meeting assigns nothing, only exact
// zjazd-N slugs are deleted and their links go with them, and a second run
// changes nothing.
func TestMoveZjazdTagsAgainstDatabase(t *testing.T) {
	_, _, gdb := migrated(t)

	insertID := func(query string, args ...any) int64 {
		t.Helper()
		var id int64
		if err := gdb.Raw(query+" RETURNING id", args...).Scan(&id).Error; err != nil {
			t.Fatalf("%s: %v", query, err)
		}
		return id
	}
	meeting := map[int]int64{}
	for _, n := range []int{2, 3, 4} {
		meeting[n] = insertID(`INSERT INTO jz_bm_meetings (number, starts_on, ends_on) VALUES (?, '2026-10-01', '2026-10-02')`, n)
	}
	tag := map[string]int64{}
	for _, slug := range []string{"zjazd-3", "zjazd-4", "zjazd-5", "zjazd-3-24-10", "globalizacja"} {
		tag[slug] = insertID(`INSERT INTO jz_bm_tags (name, slug) VALUES (?, ?)`, slug, slug)
	}
	material := func(title string, meetingID *int64, slugs ...string) int64 {
		t.Helper()
		id := insertID(`INSERT INTO jz_bm_materials (title, type, meeting_id) VALUES (?, 'notatka', ?)`, title, meetingID)
		for _, s := range slugs {
			if err := gdb.Exec(`INSERT INTO jz_bm_material_tag (material_id, tag_id) VALUES (?, ?)`, id, tag[s]).Error; err != nil {
				t.Fatal(err)
			}
		}
		return id
	}
	four := meeting[4]
	a := material("A", nil, "zjazd-3", "globalizacja")
	b := material("B", &four, "zjazd-3")
	c := material("C", nil, "zjazd-5")
	d := material("D", nil, "zjazd-4", "zjazd-3")
	e := material("E", nil, "zjazd-3-24-10")

	run := func() {
		t.Helper()
		if err := gdb.Transaction(func(tx *gorm.DB) error {
			return updates.MoveZjazdTagsToMeetings().Migrate(tx)
		}); err != nil {
			t.Fatalf("Migrate: %v", err)
		}
	}
	meetingOf := func(id int64) sql.NullInt64 {
		t.Helper()
		var m sql.NullInt64
		if err := gdb.Raw(`SELECT meeting_id FROM jz_bm_materials WHERE id = ?`, id).Scan(&m).Error; err != nil {
			t.Fatal(err)
		}
		return m
	}
	check := func(round string) {
		t.Helper()
		for _, w := range []struct {
			name string
			id   int64
			want sql.NullInt64
		}{
			{"A (zjazd-3, no meeting)", a, sql.NullInt64{Int64: meeting[3], Valid: true}},
			{"B (meeting 4, tag zjazd-3)", b, sql.NullInt64{Int64: meeting[4], Valid: true}},
			{"C (zjazd-5, no meeting 5)", c, sql.NullInt64{}},
			{"D (zjazd-4 and zjazd-3)", d, sql.NullInt64{Int64: meeting[3], Valid: true}},
			{"E (zjazd-3-24-10, a topic)", e, sql.NullInt64{}},
		} {
			if got := meetingOf(w.id); got != w.want {
				t.Errorf("%s: material %s meeting_id = %+v, want %+v", round, w.name, got, w.want)
			}
		}
		var zjazd int64
		if err := gdb.Raw(`SELECT COUNT(*) FROM jz_bm_tags WHERE slug ~ '^zjazd-[0-9]+$'`).Scan(&zjazd).Error; err != nil {
			t.Fatal(err)
		}
		if zjazd != 0 {
			t.Errorf("%s: %d zjazd-N tags remain", round, zjazd)
		}
		var kept []string
		if err := gdb.Raw(`SELECT slug FROM jz_bm_tags ORDER BY slug`).Scan(&kept).Error; err != nil {
			t.Fatal(err)
		}
		if len(kept) != 2 || kept[0] != "globalizacja" || kept[1] != "zjazd-3-24-10" {
			t.Errorf("%s: tags left %v, want [globalizacja zjazd-3-24-10]", round, kept)
		}
		var links int64
		if err := gdb.Raw(`SELECT COUNT(*) FROM jz_bm_material_tag WHERE (material_id = ? AND tag_id = ?) OR (material_id = ? AND tag_id = ?)`,
			a, tag["globalizacja"], e, tag["zjazd-3-24-10"]).Scan(&links).Error; err != nil {
			t.Fatal(err)
		}
		if links != 2 {
			t.Errorf("%s: topic links left %d, want A-globalizacja and E-zjazd-3-24-10", round, links)
		}
		var orphans int64
		if err := gdb.Raw(`SELECT COUNT(*) FROM jz_bm_material_tag mt LEFT JOIN jz_bm_tags t ON t.id = mt.tag_id WHERE t.id IS NULL`).Scan(&orphans).Error; err != nil {
			t.Fatal(err)
		}
		if orphans != 0 || count(t, gdb, "jz_bm_material_tag") != 2 {
			t.Errorf("%s: %d pivot rows point at deleted tags, %d rows in all", round, orphans, count(t, gdb, "jz_bm_material_tag"))
		}
	}

	run()
	check("first run")
	run()
	check("second run")
}