package main

import (
	"database/sql"
	"fmt"
	"math/rand/v2"
	"os"
	"time"

	_ "github.com/mattn/go-sqlite3"
)

func main() {
	if len(os.Args) < 2 {
		fmt.Fprintln(os.Stderr, "usage: backfill <db-path>")
		os.Exit(1)
	}
	db, err := sql.Open("sqlite3", os.Args[1])
	if err != nil {
		fmt.Fprintf(os.Stderr, "open: %v\n", err)
		os.Exit(1)
	}
	defer db.Close()

	ids, err := loadSiteIDs(db)
	if err != nil {
		fmt.Fprintf(os.Stderr, "load site IDs: %v\n", err)
		os.Exit(1)
	}

	rng := rand.New(rand.NewPCG(42, 0)) //nolint:gosec // deterministic seed for reproducible demo data
	now := time.Now().UTC()

	if err := backfillHistory(db, rng, now, ids); err != nil {
		fmt.Fprintf(os.Stderr, "history: %v\n", err)
		os.Exit(1)
	}
	if err := backfillStateChanges(db, now, ids); err != nil {
		fmt.Fprintf(os.Stderr, "state changes: %v\n", err)
		os.Exit(1)
	}
	if err := backfillLogs(db, now); err != nil {
		fmt.Fprintf(os.Stderr, "logs: %v\n", err)
		os.Exit(1)
	}
	if err := backfillNodes(db, now); err != nil {
		fmt.Fprintf(os.Stderr, "nodes: %v\n", err)
		os.Exit(1)
	}
	if err := backfillMaintenance(db, now, ids); err != nil {
		fmt.Fprintf(os.Stderr, "maintenance: %v\n", err)
		os.Exit(1)
	}
	alertIDs, err := loadAlertIDs(db)
	if err != nil {
		fmt.Fprintf(os.Stderr, "load alert IDs: %v\n", err)
		os.Exit(1)
	}
	if err := backfillAlertHealth(db, now, alertIDs); err != nil {
		fmt.Fprintf(os.Stderr, "alert health: %v\n", err)
		os.Exit(1)
	}

	var count int
	_ = db.QueryRow("SELECT COUNT(*) FROM check_history").Scan(&count)
	fmt.Printf("Backfill complete: %d check records\n", count)

	var token string
	if err := db.QueryRow("SELECT token FROM sites WHERE name='Nightly Backup'").Scan(&token); err == nil {
		fmt.Printf("PUSH_TOKEN=%s\n", token)
	}
}

func loadSiteIDs(db *sql.DB) (map[string]int, error) {
	rows, err := db.Query("SELECT id, name FROM sites")
	if err != nil {
		return nil, err
	}
	return scanNameIDs(rows)
}

func loadAlertIDs(db *sql.DB) (map[string]int, error) {
	rows, err := db.Query("SELECT id, name FROM alerts")
	if err != nil {
		return nil, err
	}
	return scanNameIDs(rows)
}

func scanNameIDs(rows *sql.Rows) (map[string]int, error) {
	defer rows.Close()
	ids := make(map[string]int)
	for rows.Next() {
		var id int
		var name string
		if err := rows.Scan(&id, &name); err != nil {
			return nil, err
		}
		ids[name] = id
	}
	return ids, rows.Err()
}

// backfillAlertHealth seeds realistic send health so the Alerts tab shows recent,
// healthy "last sent" times and green health dots instead of "never" across the board.
func backfillAlertHealth(db *sql.DB, now time.Time, alertIDs map[string]int) error {
	type health struct {
		name    string
		sentAgo time.Duration
		ok      bool
		sends   int
		fails   int
	}
	rows := []health{
		{"Discord Homelab", 4 * time.Minute, true, 37, 0},
		{"Slack Ops", 9 * time.Minute, true, 21, 1},
		{"Ntfy Alerts", 1 * time.Hour, true, 12, 0},
		{"Email Oncall", 3 * time.Hour, true, 5, 0},
	}

	tx, err := db.Begin()
	if err != nil {
		return err
	}
	defer func() { _ = tx.Rollback() }()

	stmt, err := tx.Prepare("INSERT OR REPLACE INTO alert_health (alert_id, last_send_at, last_send_ok, last_error, send_count, fail_count) VALUES (?, ?, ?, ?, ?, ?)")
	if err != nil {
		return err
	}
	defer stmt.Close()

	for _, r := range rows {
		id, ok := alertIDs[r.name]
		if !ok {
			continue
		}
		sentAt := now.Add(-r.sentAgo).Format("2006-01-02 15:04:05")
		if _, err := stmt.Exec(id, sentAt, r.ok, "", r.sends, r.fails); err != nil {
			return err
		}
	}
	return tx.Commit()
}

type monitorProfile struct {
	name     string
	minMs    int
	maxMs    int
	downFrom int // first DOWN check index (-1 = always up)
	downTo   int // exclusive end of the DOWN window; use 60 (total) for a still-down monitor
}

func backfillHistory(db *sql.DB, rng *rand.Rand, now time.Time, ids map[string]int) error {
	// Latency ranges reflect monitoring public services over the internet, so the
	// detail histogram brackets the live latency the engine measures at capture time.
	// 60 checks * 24m spacing = a 24h window; dip indices place outages within it.
	profiles := []monitorProfile{
		{"Nextcloud", 200, 600, 47, 48},       // brief blip ~5h ago, recovered
		{"Jellyfin", 40, 180, 15, 16},         // brief blip ~18h ago, recovered
		{"Home Assistant", 30, 120, -1, 0},    //
		{"Gitea", 50, 200, -1, 0},             //
		{"Traefik Dashboard", 60, 200, -1, 0}, //
		{"Vaultwarden", 80, 250, -1, 0},       //
		{"Personal Blog", 40, 160, -1, 0},     //
		{"Immich", 60, 300, 30, 31},           // brief blip ~12h ago; periodic spikes below
		{"Auth Portal", 30, 90, 40, 60},       // DOWN ~8h ago, still down
		{"Edge Router", 5, 20, -1, 0},         // ping
		{"Postgres", 1, 6, -1, 0},             // port
		{"DNS Primary", 8, 30, -1, 0},         // dns
	}

	tx, err := db.Begin()
	if err != nil {
		return err
	}
	defer func() { _ = tx.Rollback() }()

	stmt, err := tx.Prepare("INSERT INTO check_history (site_id, latency_ns, is_up, checked_at) VALUES (?, ?, ?, ?)")
	if err != nil {
		return err
	}
	defer stmt.Close()

	const total = 60
	for _, p := range profiles {
		siteID, ok := ids[p.name]
		if !ok {
			continue
		}
		for i := 0; i < total; i++ {
			minutesAgo := (total - i) * 24
			checkedAt := now.Add(-time.Duration(minutesAgo) * time.Minute)

			var latencyNs int64
			isUp := true

			if p.downFrom >= 0 && i >= p.downFrom && i < p.downTo {
				latencyNs = 0
				isUp = false
			} else {
				ms := p.minMs + rng.IntN(p.maxMs-p.minMs)
				if p.name == "Immich" && i%17 == 0 {
					ms = 250 + rng.IntN(100)
				}
				latencyNs = int64(ms) * 1_000_000
			}

			if _, err := stmt.Exec(siteID, latencyNs, isUp, checkedAt.Format("2006-01-02 15:04:05")); err != nil {
				return err
			}
		}
	}
	return tx.Commit()
}

func backfillStateChanges(db *sql.DB, now time.Time, ids map[string]int) error {
	type sc struct {
		name   string
		from   string
		to     string
		reason string
		at     time.Time
	}
	// Timed to line up with the history dips (Nextcloud ~5h, Immich ~12h, Jellyfin ~18h)
	// and the still-down Auth Portal (~8h), so detail panels read coherently.
	changes := []sc{
		{"Nextcloud", "UP", "DOWN", "read timeout", now.Add(-5 * time.Hour).Add(-8 * time.Minute)},
		{"Nextcloud", "DOWN", "UP", "", now.Add(-5 * time.Hour)},
		{"Auth Portal", "UP", "DOWN", "no such host", now.Add(-8 * time.Hour)},
		{"Immich", "UP", "DOWN", "502 Bad Gateway", now.Add(-12 * time.Hour).Add(-8 * time.Minute)},
		{"Immich", "DOWN", "UP", "", now.Add(-12 * time.Hour)},
		{"Jellyfin", "UP", "DOWN", "connection reset", now.Add(-18 * time.Hour).Add(-5 * time.Minute)},
		{"Jellyfin", "DOWN", "UP", "", now.Add(-18 * time.Hour)},
	}

	tx, err := db.Begin()
	if err != nil {
		return err
	}
	defer func() { _ = tx.Rollback() }()

	stmt, err := tx.Prepare("INSERT INTO state_changes (site_id, from_status, to_status, error_reason, changed_at) VALUES (?, ?, ?, ?, ?)")
	if err != nil {
		return err
	}
	defer stmt.Close()

	for _, c := range changes {
		siteID, ok := ids[c.name]
		if !ok {
			continue
		}
		if _, err := stmt.Exec(siteID, c.from, c.to, c.reason, c.at.Format("2006-01-02 15:04:05")); err != nil {
			return err
		}
	}
	return tx.Commit()
}

func backfillLogs(db *sql.DB, now time.Time) error {
	type logEntry struct {
		text string
		at   time.Time
	}
	ago := func(h, m, s int) time.Time {
		return now.Add(-(time.Duration(h)*time.Hour + time.Duration(m)*time.Minute + time.Duration(s)*time.Second))
	}
	// Ordered newest-first. The bracket time is derived from `at` (not hardcoded), so the
	// Logs view — which renders the leading [HH:MM] — reads chronologically. Outage times
	// line up with the state changes and history dips above.
	logs := []logEntry{
		{"Monitor 'Nextcloud' recovered (was down 8m)", ago(5, 0, 0)},
		{"Monitor 'Nextcloud' confirmed DOWN: read timeout", ago(5, 8, 0)},
		{"Monitor 'Nextcloud' failed check 2/2", ago(5, 8, 30)},
		{"Monitor 'Nextcloud' failed check 1/2", ago(5, 9, 0)},
		{"Monitor 'Auth Portal' confirmed DOWN: no such host", ago(8, 0, 0)},
		{"Monitor 'Auth Portal' failed check 2/2", ago(8, 0, 30)},
		{"Monitor 'Auth Portal' failed check 1/2", ago(8, 1, 0)},
		{"Monitor 'Immich' recovered (was down 8m)", ago(12, 0, 0)},
		{"Monitor 'Immich' confirmed DOWN: 502 Bad Gateway", ago(12, 8, 0)},
		{"Monitor 'Immich' failed check 3/3", ago(12, 8, 30)},
		{"Monitor 'Immich' failed check 2/3", ago(12, 9, 0)},
		{"Monitor 'Immich' failed check 1/3", ago(12, 9, 30)},
		{"Monitor 'Jellyfin' recovered (was down 5m)", ago(18, 0, 0)},
		{"Monitor 'Jellyfin' confirmed DOWN: connection reset", ago(18, 5, 0)},
		{"Monitor 'Jellyfin' failed check 2/2", ago(18, 5, 30)},
		{"Monitor 'Jellyfin' failed check 1/2", ago(18, 6, 0)},
		{"SSL warning: certificate for 'Personal Blog' expires in 9 days", ago(20, 0, 0)},
		{"Engine RESUMED (Active)", ago(22, 0, 0)},
		{"Loaded check history from database", ago(22, 0, 5)},
	}

	tx, err := db.Begin()
	if err != nil {
		return err
	}
	defer func() { _ = tx.Rollback() }()

	stmt, err := tx.Prepare("INSERT INTO logs (message, created_at) VALUES (?, ?)")
	if err != nil {
		return err
	}
	defer stmt.Close()

	for _, l := range logs {
		// Bracket in local time to match the engine's live AddLog timestamps;
		// created_at stays UTC to match the store's CURRENT_TIMESTAMP ordering.
		msg := "[" + l.at.Local().Format("15:04") + "] " + l.text
		if _, err := stmt.Exec(msg, l.at.Format("2006-01-02 15:04:05")); err != nil {
			return err
		}
	}
	return tx.Commit()
}

func backfillNodes(db *sql.DB, now time.Time) error {
	// Multiple regions to show distributed probes. All seen "now" so they read ONLINE
	// for the whole capture window (kept under the 60s freshness threshold by the tape).
	nodes := []struct{ id, name, region string }{
		{"node-use1", "leader", "us-east"},
		{"node-euw1", "probe-eu", "eu-west"},
		{"node-apse1", "probe-ap", "ap-southeast"},
	}
	ts := now.Format("2006-01-02 15:04:05")
	for _, n := range nodes {
		if _, err := db.Exec(
			"INSERT OR REPLACE INTO nodes (id, name, region, last_seen, version) VALUES (?, ?, ?, ?, ?)",
			n.id, n.name, n.region, ts, "2026.05.1",
		); err != nil {
			return err
		}
	}
	return nil
}

func backfillMaintenance(db *sql.DB, now time.Time, ids map[string]int) error {
	tx, err := db.Begin()
	if err != nil {
		return err
	}
	defer func() { _ = tx.Rollback() }()

	stmt, err := tx.Prepare("INSERT INTO maintenance_windows (monitor_id, title, description, type, start_time, end_time, created_by) VALUES (?, ?, ?, ?, ?, ?, ?)")
	if err != nil {
		return err
	}
	defer stmt.Close()

	jellyfinID := ids["Jellyfin"]
	past := now.Add(-3 * 24 * time.Hour)
	if _, err := stmt.Exec(jellyfinID, "Jellyfin upgrade", "Upgrade to v10.10 + plugin updates", "maintenance",
		past.Format("2006-01-02 15:04:05"),
		past.Add(2*time.Hour).Format("2006-01-02 15:04:05"),
		"admin"); err != nil {
		return err
	}

	future := now.Add(2 * 24 * time.Hour)
	if _, err := stmt.Exec(0, "Network switch replacement", "Replacing core switch in rack 2", "maintenance",
		future.Format("2006-01-02 15:04:05"),
		future.Add(4*time.Hour).Format("2006-01-02 15:04:05"),
		"admin"); err != nil {
		return err
	}

	return tx.Commit()
}