package main

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"testing"
	"time"

	"textmachine/backend/internal/pipeline"
)

// rebill_cli_test.go closes the D20.4 «parsed but silently ignored» regression class for
// --accept-rebill: parsing the flag correctly is worthless if the value never reaches the runner. The
// invocation tests cover the parse; this one drives the REAL `translate` entry point end-to-end against
// a mock provider, so the wiring itself is executed, not asserted about.

// writeCLIFile writes a fixture file, creating parents.
func writeCLIFile(t *testing.T, path, content string) {
	t.Helper()
	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(path, []byte(content), 0o644); err != nil {
		t.Fatal(err)
	}
}

// setupCLIProject builds the smallest runnable project (one draft stage) pointed at providerURL and
// returns the path of its book.yaml.
func setupCLIProject(t *testing.T, providerURL string) string {
	t.Helper()
	dir := t.TempDir()
	writeCLIFile(t, filepath.Join(dir, "prompts", "translator.md"),
		"Переводи с {{source_lang}} на {{target_lang}}.\n---USER---\n{{text}}")
	writeCLIFile(t, filepath.Join(dir, "models.yaml"), fmt.Sprintf(`
prices_checked: %q
default_model: fake-model
providers:
  fake:
    kind: openai
    base_url: %q
    timeouts: { attempt_s: 5, max_attempts: 2, backoff_cap_s: 1 }
models:
  fake-model:
    provider: fake
    price: { input_per_m: 1.0, cached_per_m: 0.1, cache_write_per_m: 0, output_per_m: 2.0 }
`, time.Now().UTC().Format("2006-01-02"), providerURL))
	writeCLIFile(t, filepath.Join(dir, "pipeline.yaml"), `
core: C1
version: 1
defaults: { max_output_ratio: 2.0, min_max_tokens: 512 }
retries: { regenerate_before_escalate: 0 }
context: { glossary_injection: selective, glossary_token_budget: 800 }
stages:
  - { name: draft, role: translator, model: fake-model, prompt_override: prompts/translator.md, prompt_version: v-cli, temperature: 0.3, reasoning: "off" }
`)
	writeCLIFile(t, filepath.Join(dir, "source.txt"), "静かな図書館の朝。")
	writeCLIFile(t, filepath.Join(dir, "book.yaml"), `
book_id: cli-book
title: Тест
source_lang: ja
target_lang: ru
genre: ранобэ
audience: тест
venuti: 0.5
honorifics: keep
transcription: polivanov
footnotes: minimal
pipeline: pipeline.yaml
models: models.yaml
source_file: source.txt
ceilings: { book_usd: 1.0, day_usd: 2.0 }
`)
	return filepath.Join(dir, "book.yaml")
}

// TestTranslateWiresAcceptRebill: after a config drift, `translate --resnapshot` alone must be REFUSED
// with the projected sum, and the same call carrying the consent must go through. Dropping
// `r.AcceptRebill = acceptRebill` in main.go makes the second half fail here — which is the whole point:
// the flag exists to change what the run does, not what the parser returns.
func TestTranslateWiresAcceptRebill(t *testing.T) {
	calls := 0
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_, _ = io.ReadAll(r.Body)
		calls++
		tb, _ := json.Marshal("ЧЕРНОВИК ПЕРЕВОДА")
		fmt.Fprintf(w, `{"id":"fake","model":"fake-model","choices":[{"message":{"content":%s},"finish_reason":"stop"}],
			"usage":{"prompt_tokens":1000,"completion_tokens":500,"prompt_tokens_details":{"cached_tokens":200}}}`, tb)
	}))
	defer srv.Close()
	bookPath := setupCLIProject(t, srv.URL)
	ctx := context.Background()

	if err := translate(ctx, bookPath, false, pipeline.RebillConsent{}, false, 0, 0); err != nil {
		t.Fatalf("first run: %v", err)
	}
	if calls != 1 {
		t.Fatalf("setup: the first run must bill one call, got %d", calls)
	}

	// Drift the config so the stored row's snapshot is superseded.
	pipePath := filepath.Join(filepath.Dir(bookPath), "pipeline.yaml")
	raw, err := os.ReadFile(pipePath)
	if err != nil {
		t.Fatal(err)
	}
	writeCLIFile(t, pipePath, strings.Replace(string(raw), "prompt_version: v-cli", "prompt_version: v-cli-drift", 1))

	// --resnapshot WITHOUT consent → refused, nothing called.
	err = translate(ctx, bookPath, true, pipeline.RebillConsent{}, false, 0, 0)
	if err == nil {
		t.Fatal("`translate --resnapshot` without --accept-rebill must be refused over the threshold")
	}
	if !strings.Contains(err.Error(), "--accept-rebill") {
		t.Errorf("the refusal must name the flag; got: %v", err)
	}
	if calls != 1 {
		t.Fatalf("a refused translate must reach no provider, calls=%d", calls)
	}

	// A ceiling BELOW the projection is still a refusal — proving the CAPPED value is wired, not just
	// the boolean.
	if err := translate(ctx, bookPath, true, pipeline.RebillConsent{Given: true, Capped: true, CapUSD: 0.0001}, false, 0, 0); err == nil {
		t.Fatal("a ceiling below the projection must be refused through the CLI entry point too")
	}
	if calls != 1 {
		t.Fatalf("a cap-refused translate must reach no provider, calls=%d", calls)
	}

	// Consent given → the run proceeds and really re-pays.
	if err := translate(ctx, bookPath, true, pipeline.RebillConsent{Given: true}, false, 0, 0); err != nil {
		t.Fatalf("`translate --resnapshot --accept-rebill` must proceed: %v", err)
	}
	if calls != 2 {
		t.Fatalf("the consented run must re-call the provider, calls=%d", calls)
	}
}

// TestRedriveWiresAcceptRebill is the same wiring check for the OTHER money-spending command: redrive
// carries --resnapshot too, so it carries the consent too. A redrive refused for want of consent must
// also leave the flagged row it was about to reset intact.
func TestRedriveWiresAcceptRebill(t *testing.T) {
	calls := 0
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_, _ = io.ReadAll(r.Body)
		calls++
		tb, _ := json.Marshal("Извините, я не могу перевести это.")
		fmt.Fprintf(w, `{"id":"fake","model":"fake-model","choices":[{"message":{"content":%s},"finish_reason":"stop"}],
			"usage":{"prompt_tokens":1000,"completion_tokens":500,"prompt_tokens_details":{"cached_tokens":200}}}`, tb)
	}))
	defer srv.Close()
	bookPath := setupCLIProject(t, srv.URL)
	ctx := context.Background()

	// The refusal text flags the only chunk (exit 2 is a sentinel, not an infra failure).
	if err := translate(ctx, bookPath, false, pipeline.RebillConsent{}, false, 0, 0); exitCode(err) != 2 {
		t.Fatalf("setup: the refusal fixture must complete with flags (exit 2), got %v", err)
	}
	callsAfterRun1 := calls

	pipePath := filepath.Join(filepath.Dir(bookPath), "pipeline.yaml")
	raw, err := os.ReadFile(pipePath)
	if err != nil {
		t.Fatal(err)
	}
	writeCLIFile(t, pipePath, strings.Replace(string(raw), "prompt_version: v-cli", "prompt_version: v-cli-drift", 1))

	sel := pipeline.RedriveSelector{Chapter: -1, ChunkIdx: -1}
	if err := redrive(ctx, bookPath, true, pipeline.RebillConsent{}, sel, false, 0); err == nil {
		t.Fatal("`redrive --resnapshot` without consent must be refused over the threshold")
	} else if !strings.Contains(err.Error(), "--accept-rebill") {
		t.Errorf("the redrive refusal must name the flag; got: %v", err)
	}
	if calls != callsAfterRun1 {
		t.Fatalf("a refused redrive must reach no provider, calls=%d", calls)
	}

	// Consent given → the redrive resets and re-attacks (the mock still refuses, so it ends flagged again
	// — what matters is that it RAN and billed).
	if err := redrive(ctx, bookPath, true, pipeline.RebillConsent{Given: true}, sel, false, 0); exitCode(err) != 2 {
		t.Fatalf("`redrive --resnapshot --accept-rebill` must run (and end flagged), got %v", err)
	}
	if calls <= callsAfterRun1 {
		t.Fatalf("the consented redrive must re-call the provider, calls=%d", calls)
	}
}

// TestTranslateAndRedriveWireTheRunCeiling is the same class as TestTranslateWiresAcceptRebill, for the
// flag row 145 added: it exists to change what the RUN does, not what the parser returns.
//
// It closes an audit finding — deleting `r.CeilingUSD = ceilingUSD` from either command left the whole
// backend suite green, because TestParseCeilingUSD stops at the parsed invocation and the pipeline-level
// ceiling tests set the field on the Runner directly. Neither of them touches the wire between the two.
func TestTranslateAndRedriveWireTheRunCeiling(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_, _ = io.ReadAll(r.Body)
		tb, _ := json.Marshal("ЧЕРНОВИК ПЕРЕВОДА")
		fmt.Fprintf(w, `{"id":"fake","model":"fake-model","choices":[{"message":{"content":%s},"finish_reason":"stop"}],
			"usage":{"prompt_tokens":1000,"completion_tokens":500,"prompt_tokens_details":{"cached_tokens":200}}}`, tb)
	}))
	defer srv.Close()
	ctx := context.Background()

	// A ceiling far below anything the book can cost. The book's own ceiling is comfortable, so ONLY the
	// argument can produce this stop — and only if the command actually hands it to the runner.
	const tiny = 0.000001
	err := translate(ctx, setupCLIProject(t, srv.URL), false, pipeline.RebillConsent{}, false, tiny, 0)
	if err == nil || !strings.Contains(err.Error(), "ceiling reached") {
		t.Fatalf("translate must carry --ceiling-usd into the run; got %v", err)
	}
	if !strings.Contains(err.Error(), "--ceiling-usd") {
		t.Fatalf("the stop must name the ceiling in force: %v", err)
	}

	// Same for redrive: it re-attacks with real provider calls, so an unwired flag there is a hole in
	// exactly the surface the row closes. A redrive with no targets never reserves and therefore could not
	// show a ceiling at all — so the book is first driven to a FLAGGED chunk, which gives the redrive
	// something to re-attack and makes the reservation (and the ceiling) reachable.
	refuse := true
	srv2 := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		body, _ := io.ReadAll(r.Body)
		text := "ЧЕРНОВИК ПЕРЕВОДА"
		if refuse && !strings.Contains(string(body), "Черновик перевода для редактуры") {
			text = "Извините, я не могу перевести это." // soft refusal → the chunk is flagged
		}
		tb, _ := json.Marshal(text)
		fmt.Fprintf(w, `{"id":"fake","model":"fake-model","choices":[{"message":{"content":%s},"finish_reason":"stop"}],
			"usage":{"prompt_tokens":1000,"completion_tokens":500,"prompt_tokens_details":{"cached_tokens":200}}}`, tb)
	}))
	defer srv2.Close()
	bookPath := setupCLIProject(t, srv2.URL)
	if err := translate(ctx, bookPath, false, pipeline.RebillConsent{}, false, 0, 0); exitCode(err) != 2 {
		t.Fatalf("setup: the run must finish WITH a flagged chunk (exit 2), got %v", err)
	}
	refuse = false
	sel := pipeline.RedriveSelector{Chapter: -1, ChunkIdx: -1}
	err = redrive(ctx, bookPath, false, pipeline.RebillConsent{}, sel, false, tiny)
	if err == nil || !strings.Contains(err.Error(), "ceiling reached") {
		t.Fatalf("redrive must carry --ceiling-usd into the re-attack; got %v", err)
	}
}

// setupCLIProjectMulti is setupCLIProject with a source long enough — and a draft cut fine enough — to
// produce SEVERAL output units, which is what a volume ceiling needs in order to bite at all.
func setupCLIProjectMulti(t *testing.T, providerURL string) string {
	t.Helper()
	bookPath := setupCLIProject(t, providerURL)
	dir := filepath.Dir(bookPath)
	writeCLIFile(t, filepath.Join(dir, "source.txt"),
		"静かな図書館の朝。鈴木は本を読んだ。外では雨が降っていた。彼は窓を見た。時間は静かに過ぎた。夜になった。")
	writeCLIFile(t, filepath.Join(dir, "pipeline.yaml"), `
core: C1
version: 1
defaults: { max_output_ratio: 2.0, min_max_tokens: 512 }
retries: { regenerate_before_escalate: 0 }
context: { glossary_injection: selective, glossary_token_budget: 800 }
segmentation:
  draft_budget_out: 24
  edit_ceiling_out: 48
  fertility: { cjk: 1.1978, other: 0.3852 }
stages:
  - { name: draft, role: translator, model: fake-model, prompt_override: prompts/translator.md, prompt_version: v-cli, temperature: 0.3, reasoning: "off" }
`)
	return bookPath
}

// TestTranslateWiresMaxUnits is the same kind of pin as TestTranslateWiresAcceptRebill above, for the
// other run ceiling: it proves the flag changes what the RUN DOES, not merely what the parser returns.
//
// Every other proof of the volume ceiling sets Runner.MaxUnits directly, which leaves exactly one line
// unverified — `r.MaxUnits = maxUnits` in main.go's translate(). That line is the entire seam between the
// flag a platform passes and the engine that honours it; dropping it would leave every volume test in the
// pipeline package green while `tmctl translate --max-units 2` translated the whole book.
func TestTranslateWiresMaxUnits(t *testing.T) {
	var mu sync.Mutex
	calls := 0
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_, _ = io.ReadAll(r.Body)
		mu.Lock()
		calls++
		mu.Unlock()
		tb, _ := json.Marshal("ЧЕРНОВИК ПЕРЕВОДА")
		fmt.Fprintf(w, `{"id":"fake","model":"fake-model","choices":[{"message":{"content":%s},"finish_reason":"stop"}],
			"usage":{"prompt_tokens":1000,"completion_tokens":500,"prompt_tokens_details":{"cached_tokens":200}}}`, tb)
	}))
	defer srv.Close()
	bookPath := setupCLIProjectMulti(t, srv.URL)
	ctx := context.Background()

	// Unbounded first, on a throwaway copy of the project, to learn how many units this book really has —
	// so the bounded assertion below is against a measured number rather than a guessed one.
	fullPath := setupCLIProjectMulti(t, srv.URL)
	if err := translate(ctx, fullPath, false, pipeline.RebillConsent{}, false, 0, 0); err != nil {
		t.Fatalf("the unbounded baseline must complete: %v", err)
	}
	mu.Lock()
	total := calls
	calls = 0
	mu.Unlock()
	if total < 3 {
		t.Fatalf("fixture is too thin to bound: the whole book took %d call(s), so a ceiling of 2 proves nothing", total)
	}

	// Now the same book through the CLI entry point WITH the flag.
	if err := translate(ctx, bookPath, false, pipeline.RebillConsent{}, false, 0, 2); err != nil {
		t.Fatalf("a volume-bounded run is a completion, not an error: %v", err)
	}
	mu.Lock()
	bounded := calls
	mu.Unlock()
	if bounded != 2 {
		t.Fatalf("`translate --max-units 2` made %d provider call(s) on a %d-unit book: the flag did not reach the engine (main.go's `r.MaxUnits = maxUnits`)", bounded, total)
	}
}