package processing

import (
	"context"
	"strings"
	"testing"
)

func TestHashEnhanceInput_stableAndSensitive(t *testing.T) {
	attrs := map[string]any{"brand": "Acme", "color": "Red"}
	a := HashEnhanceInput("Shoes", "Runner", "A shoe", "", "", "", "", attrs)
	b := HashEnhanceInput("Shoes", "Runner", "A shoe", "", "", "", "", attrs)
	if a == "" || a != b {
		t.Fatalf("expected stable hash, got %q vs %q", a, b)
	}
	if HashEnhanceInput("Shoes", "Runner X", "A shoe", "", "", "", "", attrs) == a {
		t.Fatal("name change must change hash")
	}
	if HashEnhanceInput("Shoes", "Runner", "A shoe", "Brand:\n- tone: bold", "", "", "", attrs) == a {
		t.Fatal("brand prompt must change hash")
	}
	if HashEnhanceInput("Shoes", "Runner", "A shoe", "", "", "sys-a", "user-a", attrs) == a {
		t.Fatal("prompt template change must change hash")
	}
	if HashEnhanceInput("Shoes", "Runner", "A shoe", "", "fr", "", "", attrs) == a {
		t.Fatal("language change must change hash")
	}
	// Attr key order must not matter (CompactAttrs + json map sort).
	attrs2 := map[string]any{"color": "Red", "brand": "Acme"}
	if HashEnhanceInput("Shoes", "Runner", "A shoe", "", "", "", "", attrs2) != a {
		t.Fatal("attr key order must not change hash")
	}
}

func TestRunSteps_skipsEnhanceWhenInputHashUnchanged(t *testing.T) {
	calls := 0
	e := &Engine{
		Completer: stubCompleter{fn: func(system, user string) (Completion, error) {
			calls++
			return Completion{Text: `{"name":"ShouldNotRun","description":"Nope"}`, TotalTokens: 9}, nil
		}},
		Vector: NoopVectorCategorizer{},
	}
	in := ProductInput{
		Name:                      "Widget",
		Description:               "A widget",
		Mapped:                    map[string]any{"name": "Widget", "description": "A widget"},
		PriorProcessedName:        "Cached Widget",
		PriorProcessedDescription: "Cached description.",
	}
	// First pass without prior hash to compute the hash shape via enhance path is awkward;
	// compute the same hash RunSteps will see after normalize (name/desc from mapped).
	// enhance_only: normalize then enhance with out.Name from normalized.
	normName := "Widget"
	normDesc := "A widget"
	sysTpl, userTpl := resolveProductPromptTemplates(ProductInput{})
	in.PriorEnhanceHash = HashEnhanceInput("", normName, normDesc, "", "", sysTpl, userTpl, map[string]any{})

	out, err := e.RunSteps(context.Background(), "co", in, "enhance_only", nil, StepPolicy{AllowAI: true, AllowEPREL: true})
	if err != nil {
		t.Fatal(err)
	}
	if calls != 0 {
		t.Fatalf("expected LLM skip, calls=%d", calls)
	}
	if out.ProcessedName != "Cached Widget" {
		t.Fatalf("name=%q", out.ProcessedName)
	}
	if out.ProcessedDescription != "Cached description." {
		t.Fatalf("desc=%q", out.ProcessedDescription)
	}
	if out.TotalTokens != 0 {
		t.Fatalf("tokens=%d want 0", out.TotalTokens)
	}
	if out.FieldSources[FieldEnhanceInputHash] != in.PriorEnhanceHash {
		t.Fatalf("hash field=%v", out.FieldSources[FieldEnhanceInputHash])
	}
	if src, _ := out.FieldSources["name"].(string); src != "ai_enhance_unchanged" {
		t.Fatalf("name source=%v", out.FieldSources["name"])
	}
	if !out.SkipCreditDebit {
		t.Fatal("expected SkipCreditDebit when enhance hash unchanged")
	}
	if shouldDebitProductProcessing(false, out) {
		t.Fatal("processOne must not debit when enhance unchanged")
	}
	joined := strings.Join(out.Notes, ";")
	if !strings.Contains(joined, "unchanged") {
		t.Fatalf("notes=%v", out.Notes)
	}
}

func TestRunSteps_callsEnhanceWhenInputHashDiffers(t *testing.T) {
	calls := 0
	e := &Engine{
		Completer: stubCompleter{fn: func(system, user string) (Completion, error) {
			calls++
			return Completion{Text: `{"name":"Fresh","description":"New copy."}`, TotalTokens: 3}, nil
		}},
		Vector: NoopVectorCategorizer{},
	}
	out, err := e.RunSteps(context.Background(), "co", ProductInput{
		Mapped:                    map[string]any{"name": "Widget", "description": "A widget"},
		PriorEnhanceHash:          "deadbeef",
		PriorProcessedName:        "Old",
		PriorProcessedDescription: "Old desc",
	}, "enhance_only", nil, StepPolicy{AllowAI: true, AllowEPREL: true})
	if err != nil {
		t.Fatal(err)
	}
	if calls != 1 {
		t.Fatalf("calls=%d", calls)
	}
	if out.ProcessedName != "Fresh" {
		t.Fatalf("name=%q", out.ProcessedName)
	}
	if out.TotalTokens != 3 {
		t.Fatalf("tokens=%d", out.TotalTokens)
	}
	if out.SkipCreditDebit {
		t.Fatal("hash miss must still debit")
	}
	if !shouldDebitProductProcessing(false, out) {
		t.Fatal("expected debit when enhance ran")
	}
	h, _ := out.FieldSources[FieldEnhanceInputHash].(string)
	if h == "" || h == "deadbeef" {
		t.Fatalf("expected new hash in field_sources, got %q", h)
	}
}