package store

import (
	"fmt"
	"time"
)

// R-1346 (2026-10-30): the statements the measurement named, in one place so the plan test reads the exact SQL the
// code runs (r1346_speed_test.go TestR1346_HeavyStatementsUseTheirIndex).

// queryNewestControllerVersion — the vouch save's R-120 fleet check (configs.go handleSetArtifacts).
const queryNewestControllerVersion = `SELECT DISTINCT controller_version FROM reports WHERE controller_version IS NOT NULL AND controller_version != ''`

// queryHostAgentVersionsSeen — the hourly OS alarm, for a box with no healthy OS report.
const queryHostAgentVersionsSeen = `SELECT COALESCE(agent_version, ''), MIN(received_at) FROM host_reports WHERE host_id = ? GROUP BY agent_version`

// queryPruneReports / queryPruneHostReports — the 04:30 retention prune (Prune).
const (
	queryPruneReports     = `DELETE FROM reports WHERE received_at < ?`
	queryPruneHostReports = `DELETE FROM host_reports WHERE received_at < ?`
)

// queryFleetAppSummary — the apps page (GetFleetAppSummary).
const queryFleetAppSummary = `
		SELECT app_name,
		       MAX(display_name) as display_name,
		       COUNT(DISTINCT customer_id) as deployment_count,
		       AVG(memory_avg_mb) as avg_memory_mb,
		       MAX(memory_peak_mb) as peak_memory_mb,
		       AVG(cpu_avg_percent) as avg_cpu,
		       SUM(log_errors) as total_errors,
		       SUM(log_warnings) as total_warnings,
		       MAX(catalog_estimate) as catalog_estimate,
		       MAX(catalog_limit) as catalog_limit
		FROM app_telemetry INDEXED BY idx_app_telemetry_prune
		WHERE reported_at > ?
		GROUP BY app_name
		ORDER BY deployment_count DESC, avg_memory_mb DESC`

// r1346Indexes lets the statements above read only what they need. controller_version and agent_version sit AFTER
// report_json in their rows, so without an index every read of them walks each row's whole JSON (overflow pages);
// received_at has no index of its own, so the prune scanned both tables INSIDE its write lock (39 s on 2026-10-30,
// and a controller report refused with „database is locked" meanwhile). Built once, at the first start that has them:
// 63 s measured on a copy of the live database in the hub pod (256 MiB) — inside the startup probe's 180 s with the
// measured 31–36 s start (R-1326).
var r1346Indexes = []struct{ name, ddl string }{
	{"idx_reports_received", `CREATE INDEX IF NOT EXISTS idx_reports_received ON reports(received_at)`},
	{"idx_host_reports_received", `CREATE INDEX IF NOT EXISTS idx_host_reports_received ON host_reports(received_at)`},
	{"idx_reports_controller_version", `CREATE INDEX IF NOT EXISTS idx_reports_controller_version ON reports(controller_version)`},
	{"idx_host_reports_agent_version", `CREATE INDEX IF NOT EXISTS idx_host_reports_agent_version ON host_reports(host_id, agent_version, received_at)`},
}

func (s *Store) migrateR1346Indexes() error {
	for _, ix := range r1346Indexes {
		var n int
		if err := s.db.QueryRow(`SELECT COUNT(*) FROM sqlite_master WHERE type = 'index' AND name = ?`, ix.name).Scan(&n); err != nil {
			return err
		}
		if n > 0 {
			continue
		}
		began := time.Now()
		if _, err := s.db.Exec(ix.ddl); err != nil {
			return fmt.Errorf("%s: %w", ix.name, err)
		}
		if s.logger != nil {
			s.logger.Printf("[INFO] store: index %s built in %s (R-1346, once)", ix.name, time.Since(began).Round(time.Millisecond))
		}
	}
	return nil
}