// Command routereval is the OFFLINE router-replay harness for the §11 P1 gate. It reads
// a golden set of (message, recorded classifier verdict, expected route, factual flag),
// replays each item through the REAL decision functions (routedecide.ClassifyLayer0 +
// CombineWithFloors — the same code package main uses, never a copy), and reports the
// confusion matrix + the four P1 metrics: false-grok-on-factual (the lie metric),
// false-web, trivial-leak, misroute. It is fully deterministic and needs no network: it
// measures the ROUTING LAYER given a verdict, so you can sweep WEB_PARANOID and the
// floors instantly. (Classifier accuracy itself is a separate LIVE check — §11 P2.)
//
// The lie label on the web path uses the citation-presence proxy by convention: a golden
// item's `factual:true` + `expected_route:web_then_grok` marks "this MUST ground"; an
// LLM-judge over query+answer is the higher-fidelity option to wire later (§14.6/§15).
//
// Usage:
//
//	go run ./cmd/routereval -golden cmd/routereval/golden_sample.json
//	go run ./cmd/routereval -golden set.json -web-floor 0.7         # sweep the needs_web floor
//
// NOTE: golden_sample.json is labelled for the PRODUCTION config (paranoid ON) — its
// expected_route values assume the epistemic web arms are active. Running -paranoid=false
// against it is a what-if sweep that WILL report NO-GO (the entity facts fall to grok by
// design); it is NOT a passing baseline. To evaluate the paranoid-off behaviour, label a
// separate set whose expected_route reflects freshness-only web routing.
package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"os"

	rd "vojo.chat/ai-bot/internal/routedecide"
)

// goldenItem is one labelled row. Message drives the free Layer-0; Verdict is the
// recorded classifier output; ExpectedRoute + Factual are the ground-truth labels.
type goldenItem struct {
	Name          string     `json:"name"`
	Message       string     `json:"message"`
	Verdict       rd.Verdict `json:"verdict"`
	ExpectedRoute string     `json:"expected_route"`
	Factual       bool       `json:"factual"` // a checkable-fact query that MUST ground
}

func main() {
	goldenPath := flag.String("golden", "cmd/routereval/golden_sample.json", "path to the golden-set JSON")
	paranoid := flag.Bool("paranoid", true, "apply the WEB_PARANOID classifier-driven web arms")
	webFloor := flag.Float64("web-floor", rd.WebNeedsWebFloor, "needs_web confidence floor to sweep")
	trivialFloor := flag.Float64("trivial-floor", rd.TrivialFloor, "trivial confidence floor")
	verbose := flag.Bool("v", false, "print every item, not just the mismatches")
	flag.Parse()

	raw, err := os.ReadFile(*goldenPath)
	if err != nil {
		fmt.Fprintf(os.Stderr, "read golden set: %v\n", err)
		os.Exit(2)
	}
	var items []goldenItem
	if err := json.Unmarshal(raw, &items); err != nil {
		fmt.Fprintf(os.Stderr, "parse golden set: %v\n", err)
		os.Exit(2)
	}
	if len(items) == 0 {
		fmt.Fprintln(os.Stderr, "golden set is empty")
		os.Exit(2)
	}

	floors := rd.Floors{WebNeedsWeb: *webFloor, Trivial: *trivialFloor}
	fmt.Printf("routereval: %d items | paranoid=%v web-floor=%.2f trivial-floor=%.2f\n\n",
		len(items), *paranoid, *webFloor, *trivialFloor)

	var (
		correct                         int
		factualWeb, factualWebMissed    int // denominator/numerator of false-grok-on-factual
		nonWebExpected, falseWeb        int
		nonTrivialExpected, trivialLeak int
	)
	roadHouseSeen := false
	roadHousePass := true
	for _, it := range items {
		l0 := rd.ClassifyLayer0(it.Message)
		got := rd.CombineWithFloors(l0, it.Verdict, *paranoid, floors).Route
		ok := got == it.ExpectedRoute
		if ok {
			correct++
		}
		if it.Factual && it.ExpectedRoute == rd.RouteWeb {
			factualWeb++
			if got == rd.RouteGrokDirect {
				factualWebMissed++ // a confident-lie risk: a checkable fact answered from memory
			}
		}
		if it.ExpectedRoute != rd.RouteWeb {
			nonWebExpected++
			if got == rd.RouteWeb {
				falseWeb++
			}
		}
		if it.ExpectedRoute != rd.RouteTrivial {
			nonTrivialExpected++
			if got == rd.RouteTrivial {
				trivialLeak++
			}
		}
		// The Road House regression pair must pass (its name carries "road house").
		if contains(it.Name, "road house") {
			roadHouseSeen = true
			if !ok {
				roadHousePass = false
			}
		}
		if *verbose || !ok {
			flag := "ok "
			if !ok {
				flag = "MISS"
			}
			fmt.Printf("  [%s] %-40s want=%-16s got=%-16s\n", flag, trunc(it.Name, 40), it.ExpectedRoute, got)
		}
	}

	rate := func(num, den int) float64 {
		if den == 0 {
			return 0
		}
		return float64(num) / float64(den)
	}
	misroute := 1 - rate(correct, len(items))
	lie := rate(factualWebMissed, factualWeb)
	fw := rate(falseWeb, nonWebExpected)
	leak := rate(trivialLeak, nonTrivialExpected)

	fmt.Printf("\n— metrics (§11 P1 gates) —\n")
	fmt.Printf("  false-grok-on-FACTUAL : %5.1f%%  (%d/%d)   gate < 5%%   %s\n", lie*100, factualWebMissed, factualWeb, pass(lie < 0.05))
	fmt.Printf("  false-web             : %5.1f%%  (%d/%d)   gate ≤ 15%%  %s\n", fw*100, falseWeb, nonWebExpected, pass(fw <= 0.15))
	fmt.Printf("  trivial-leak          : %5.1f%%  (%d/%d)   gate ~ 0%%   %s\n", leak*100, trivialLeak, nonTrivialExpected, pass(leak == 0))
	fmt.Printf("  misroute              : %5.1f%%  (%d/%d)   gate < 3%%   %s\n", misroute*100, len(items)-correct, len(items), pass(misroute < 0.03))
	if roadHouseSeen {
		fmt.Printf("  road-house pair       : %s\n", pass(roadHousePass))
	}

	// Exit non-zero if any gate fails, so the harness is CI/owner-runnable as a go/no-go.
	if lie >= 0.05 || fw > 0.15 || leak > 0 || misroute >= 0.03 || (roadHouseSeen && !roadHousePass) {
		fmt.Println("\nRESULT: NO-GO (a P1 gate failed)")
		os.Exit(1)
	}
	fmt.Println("\nRESULT: GO")
}

func pass(ok bool) string {
	if ok {
		return "PASS"
	}
	return "FAIL"
}

func contains(s, sub string) bool {
	return len(sub) == 0 || indexFold(s, sub) >= 0
}

// indexFold is a tiny case-insensitive substring search (avoids importing strings just
// for ToLower+Index in this small tool).
func indexFold(s, sub string) int {
	ls, lsub := toLower(s), toLower(sub)
	for i := 0; i+len(lsub) <= len(ls); i++ {
		if ls[i:i+len(lsub)] == lsub {
			return i
		}
	}
	return -1
}

func toLower(s string) string {
	b := []byte(s)
	for i, c := range b {
		if 'A' <= c && c <= 'Z' {
			b[i] = c + ('a' - 'A')
		}
	}
	return string(b)
}

func trunc(s string, n int) string {
	r := []rune(s)
	if len(r) <= n {
		return s
	}
	return string(r[:n-1]) + "…"
}