package phraser

import (
	"context"
	"math/rand"
	"strings"
	"testing"
	"time"

	"github.com/kami/maven/internal/loop"
	"github.com/kami/maven/internal/store"
)

// cand builds a candidate the way a tick would.
func cand(rule string, sinceMin int, factKey string) loop.Candidate {
	now := time.Date(2026, 7, 31, 21, 40, 0, 0, time.UTC)
	st := loop.State{Now: now, Facts: map[string]store.Fact{}}
	if sinceMin > 0 || factKey != "" {
		key := rule
		if factKey != "" {
			key = factKey
		}
		st.Facts[rule] = store.Fact{Key: key, Ts: now.Add(-time.Duration(sinceMin) * time.Minute)}
	}
	return loop.Candidate{Rule: loop.Rule{Name: rule, Severity: loop.Sev1}, Severity: loop.Sev1, State: st}
}

func newTestTemplates(t *testing.T, seed int64) *NudgeTemplates {
	t.Helper()
	nt, err := NewNudgeTemplates(rand.NewSource(seed))
	if err != nil {
		t.Fatalf("NewNudgeTemplates: %v", err)
	}
	return nt
}

func TestNudgeTemplatesLoad(t *testing.T) {
	nt := newTestTemplates(t, 1)
	for _, rule := range []string{"water", "meal", "break", "service_down", "netdata_critical", "routine", "morning", "default"} {
		set, ok := nt.file.Rules[rule]
		if !ok {
			t.Errorf("no templates for %q", rule)
			continue
		}
		if len(set.Variants) < 5 {
			t.Errorf("%s: only %d variants", rule, len(set.Variants))
		}
		// Every rule needs one variant that needs no value, or a candidate
		// without context has nothing to say. routine and morning are exempt:
		// they always carry a name and must always say it.
		plain := 0
		seen := map[string]bool{}
		for _, v := range set.Variants {
			if !placeholderRE.MatchString(v) {
				plain++
			}
			if seen[v] {
				t.Errorf("%s: duplicate variant %q", rule, v)
			}
			seen[v] = true
		}
		if plain == 0 && rule != "routine" && rule != "morning" {
			t.Errorf("%s: every variant needs a placeholder value", rule)
		}
	}
}

// The whole point of the picker: never the same words twice in a row.
func TestNudgeNoImmediateRepeat(t *testing.T) {
	nt := newTestTemplates(t, 7)
	prev := ""
	for i := 0; i < 200; i++ {
		body, _ := nt.Nudge(cand("water", 200, ""))
		if body == prev {
			t.Fatalf("repeat at %d: %q", i, body)
		}
		prev = body
	}
}

// Same seed, same sequence — otherwise the fixture score would drift run to run.
func TestNudgeDeterministicWithSeed(t *testing.T) {
	var runs [2][]string
	for r := range runs {
		nt := newTestTemplates(t, 42)
		for i := 0; i < 20; i++ {
			body, _ := nt.Nudge(cand("break", 100, ""))
			runs[r] = append(runs[r], body)
		}
	}
	for i := range runs[0] {
		if runs[0][i] != runs[1][i] {
			t.Fatalf("run %d differs: %q vs %q", i, runs[0][i], runs[1][i])
		}
	}
}

// A variant is only used when its value exists, and nothing half-filled ships.
func TestNudgeNoLeftoverPlaceholders(t *testing.T) {
	nt := newTestTemplates(t, 3)
	cases := []loop.Candidate{
		cand("water", 0, ""),   // no duration
		cand("water", 30, ""),  // under an hour
		cand("water", 200, ""), // hours
		cand("service_down", 3, "vaultwarden"),
		cand("service_down", 3, ""), // no service name
		cand("routine:таблетки", 0, ""),
		cand("morning:утро", 0, ""),
		cand("unknown_rule", 0, ""),
	}
	for _, c := range cases {
		for i := 0; i < 40; i++ {
			body, mood := nt.Nudge(c)
			if body == "" {
				t.Fatalf("%s: empty body", c.Rule.Name)
			}
			if strings.ContainsAny(body, "{}%") {
				t.Fatalf("%s: unfilled template %q", c.Rule.Name, body)
			}
			if mood != "neutral" {
				t.Fatalf("%s: mood %q", c.Rule.Name, mood)
			}
		}
	}
}

// The routine name must actually land in the text.
func TestNudgeSubstitutesWhat(t *testing.T) {
	nt := newTestTemplates(t, 11)
	for i := 0; i < 40; i++ {
		body, _ := nt.Nudge(cand("routine:таблетки", 0, ""))
		if !strings.Contains(strings.ToLower(body), "таблетки") {
			t.Fatalf("routine text lost the name: %q", body)
		}
	}
}

func TestRuSinceWords(t *testing.T) {
	cases := []struct {
		min  int
		want string
	}{
		{30, ""},
		{60, "час"},
		{95, "полтора часа"},
		{150, "два с половиной часа"},
		{190, "три часа"},
		{240, "четыре часа"},
		{430, "семь часов"},
		{660, "одиннадцать часов"},
		{60 * 30, "больше суток"},
	}
	for _, c := range cases {
		got := ruSinceWords(time.Duration(c.min) * time.Minute)
		if got != c.want {
			t.Errorf("%d min: got %q want %q", c.min, got, c.want)
		}
	}
}

// Templates are the default: a nudge must not reach the model at all.
func TestLLMPhraserUsesTemplatesByDefault(t *testing.T) {
	spy := newGrammarSpy(t)
	p := NewLLMPhraserAt(spy.srv.URL, Config{})
	pn, err := p.PhraseNudge(context.Background(), cand("water", 200, ""))
	if err != nil {
		t.Fatalf("PhraseNudge: %v", err)
	}
	if len(spy.grammars) != 0 {
		t.Errorf("nudge hit the model %d times, want 0", len(spy.grammars))
	}
	if !strings.Contains(strings.ToLower(pn.Body), "вод") {
		t.Errorf("nudge is not the water template: %q", pn.Body)
	}
}

// ...and the flag brings the model back.
func TestLLMNudgesFlagRestoresTheModel(t *testing.T) {
	spy := newGrammarSpy(t)
	p := NewLLMPhraserAt(spy.srv.URL, Config{LLMNudges: true})
	pn, err := p.PhraseNudge(context.Background(), cand("water", 200, ""))
	if err != nil {
		t.Fatalf("PhraseNudge: %v", err)
	}
	if len(spy.grammars) != 1 {
		t.Fatalf("nudge hit the model %d times, want 1", len(spy.grammars))
	}
	if pn.Body != "ага" {
		t.Errorf("body = %q, want the model's reply", pn.Body)
	}
}

func TestNudgeTemplatesPhraseNudge(t *testing.T) {
	nt := newTestTemplates(t, 5)
	pn, err := nt.PhraseNudge(context.Background(), cand("water", 200, ""))
	if err != nil {
		t.Fatalf("PhraseNudge: %v", err)
	}
	if pn.Body == "" || pn.Summary != pn.Body || pn.Mood != "neutral" {
		t.Fatalf("bad nudge: %+v", pn)
	}
}