package wing_test

import (
	"context"
	"errors"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"github.com/mathiasbq/hyperguild/ingestion/internal/wing"
)

type fakeClassifier struct {
	s     wing.Suggestion
	err   error
	calls int
}

func (f *fakeClassifier) Classify(_ context.Context, _ string, _ []string) (wing.Suggestion, error) {
	f.calls++
	return f.s, f.err
}

type fakeScorer map[string]float64

func (f fakeScorer) Score(string) map[string]float64 { return f }

// eligibleExcept allows every name except the listed ones. Being permissive on
// names it has never heard of means only the "known wing" check can stop an
// invented wing, so a test of that check cannot pass by accident.
func eligibleExcept(names ...string) func(string) bool {
	deny := map[string]bool{}
	for _, n := range names {
		deny[n] = true
	}
	return func(w string) bool { return !deny[w] }
}

func newResolver(c wing.Classifier, s wing.Scorer) wing.Resolver {
	return wing.Resolver{
		Known:      []string{"homelab", "hyperguild", "tapir", "rikatillsammans"},
		Eligible:   eligibleExcept("rikatillsammans"), // a client wing: known, never auto
		Classifier: c,
		Scorer:     s,
		Threshold:  0.8,
	}
}

func TestResolve_ExplicitSignal(t *testing.T) {
	tests := []struct {
		name     string
		note     wing.Note
		want     wing.Source
		wantWing string
	}{
		{"subfolder of a known eligible wing", wing.Note{Dir: "homelab"}, wing.Explicit, "homelab"},
		{"frontmatter of a known eligible wing", wing.Note{FrontmatterWing: "tapir"}, wing.Explicit, "tapir"},
		{"subfolder and frontmatter agree", wing.Note{Dir: "tapir", FrontmatterWing: "tapir"}, wing.Explicit, "tapir"},
		{"subfolder and frontmatter disagree", wing.Note{Dir: "tapir", FrontmatterWing: "homelab"}, wing.Exception, ""},
		{"unknown wing is never created", wing.Note{Dir: "hoemlab"}, wing.Exception, "hoemlab"},
		{"known but not eligible (client) wing is never auto-assigned", wing.Note{Dir: "rikatillsammans"}, wing.Exception, "rikatillsammans"},
		{"subfolder is case-insensitive", wing.Note{Dir: "HomeLab"}, wing.Explicit, "homelab"},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			c := &fakeClassifier{}
			d := newResolver(c, fakeScorer{}).Resolve(context.Background(), tt.note)
			assert.Equal(t, tt.want, d.Source)
			assert.Equal(t, tt.wantWing, d.Wing)
			assert.Zero(t, c.calls, "an explicit signal must not spend an LLM call")
			assert.NotEmpty(t, d.Reason)
		})
	}
}

func TestResolve_Classified(t *testing.T) {
	tests := []struct {
		name     string
		sugg     wing.Suggestion
		err      error
		scores   fakeScorer
		want     wing.Source
		wantWing string
	}{
		{"confident and scorer agrees", wing.Suggestion{Wing: "tapir", Confidence: 0.9}, nil, fakeScorer{"tapir": 3, "homelab": 1}, wing.Classified, "tapir"},
		{"confidence exactly at threshold passes", wing.Suggestion{Wing: "tapir", Confidence: 0.8}, nil, fakeScorer{"tapir": 3}, wing.Classified, "tapir"},
		{"below threshold is an exception, proposal kept", wing.Suggestion{Wing: "tapir", Confidence: 0.79}, nil, fakeScorer{"tapir": 3}, wing.Exception, "tapir"},
		{"scorer disagrees", wing.Suggestion{Wing: "tapir", Confidence: 0.95}, nil, fakeScorer{"homelab": 5, "tapir": 1}, wing.Exception, "tapir"},
		{"scorer has no opinion also needs review", wing.Suggestion{Wing: "tapir", Confidence: 0.95}, nil, fakeScorer{}, wing.Exception, "tapir"},
		{"classifier proposes a client wing", wing.Suggestion{Wing: "rikatillsammans", Confidence: 0.99}, nil, fakeScorer{"rikatillsammans": 9}, wing.Exception, "rikatillsammans"},
		{"classifier invents a wing", wing.Suggestion{Wing: "brand-new-wing", Confidence: 0.99}, nil, fakeScorer{"brand-new-wing": 9}, wing.Exception, "brand-new-wing"},
		{"classifier abstains", wing.Suggestion{Wing: "", Confidence: 0}, nil, fakeScorer{"tapir": 3}, wing.Exception, ""},
		{"classifier error", wing.Suggestion{}, errors.New("llm down"), fakeScorer{"tapir": 3}, wing.Exception, ""},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			c := &fakeClassifier{s: tt.sugg, err: tt.err}
			d := newResolver(c, tt.scores).Resolve(context.Background(), wing.Note{Text: "some note"})
			assert.Equal(t, tt.want, d.Source)
			assert.Equal(t, tt.wantWing, d.Wing)
			assert.NotEmpty(t, d.Reason, "every decision says why, so a spot-check can judge it")
			assert.Equal(t, 1, c.calls)
		})
	}
}

func TestResolve_NilDependenciesFailClosed(t *testing.T) {
	r := wing.Resolver{Known: []string{"tapir"}, Eligible: eligibleExcept(), Threshold: 0.8}
	d := r.Resolve(context.Background(), wing.Note{Text: "x"})
	require.Equal(t, wing.Exception, d.Source, "no classifier configured must route to review, not panic or guess")
}