// Package lexicon_meta holds the project-wide lexicon firewall meta-test
// (REQ-012, G-004, G-009). It is the durable firewall created in v0.2 P1
// Wave 3; P5-01-01 EXTENDS it rather than recreating it.
//
// The meta-test scans every .go file under x/ (production + test) for the 9
// banned financial terms and fails on any hit. It includes a self-test table
// (G-009) of synthetic strings — one per banned term — asserted to each
// trigger detection, so the meta-test's own detection coverage is durably
// verified without manual spikes.
//
// The meta-test file itself is excluded from the scan (it must reference the
// banned terms via the shared lexicon package, whose source assembles terms
// from fragments so no banned term appears as a literal substring anywhere
// in the firewall's own code — the standard lexicon-test bootstrapping
// pattern).
package lexicon_meta

import (
	"os"
	"path/filepath"
	"runtime"
	"strings"
	"testing"

	"github.com/oy/openyield/lexicon"
)

// TestLexiconMetaNoBannedTermsInX is the project-wide firewall (G-004).
// It walks every .go file under x/ (production + test), reads its source,
// and asserts no banned term is present (word-boundary, case-insensitive).
// The meta-test file itself is excluded (it is the firewall's own code and
// references the banned terms via the lexicon package, whose source uses
// fragments).
//
// Passes at P1: the v0.1 baseline (15 modules) plus the 3 new P1 modules
// (window, stand, guild) are all lexicon-clean.
func TestLexiconMetaNoBannedTermsInX(t *testing.T) {
	xRoot := repoXRoot(t)
	thisFile := thisFile(t)
	hits := []string{}
	err := filepath.Walk(xRoot, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		if info.IsDir() {
			return nil
		}
		if !strings.HasSuffix(path, ".go") {
			return nil
		}
		// Exclude the meta-test file itself (the firewall's own code).
		if path == thisFile {
			return nil
		}
		bz, rerr := os.ReadFile(path)
		if rerr != nil {
			return rerr
		}
		if found, ok := lexicon.FindBannedTerm(string(bz)); ok {
			rel, _ := filepath.Rel(xRoot, path)
			hits = append(hits, rel+" contains banned term "+found)
		}
		return nil
	})
	if err != nil {
		t.Fatalf("walk: %v", err)
	}
	if len(hits) > 0 {
		t.Errorf("REQ-012 lexicon firewall violations:\n  %s",
			strings.Join(hits, "\n  "))
	}
}

// TestLexiconMetaSelfTestTable (G-009) is the meta-test's own coverage
// firewall. Each synthetic string is asserted to trigger detection so the
// firewall's detection logic is durably verified — if detection ever breaks,
// this test fails before the firewall silently passes a real violation.
//
// The synthetic strings are assembled from fragments so this file does not
// contain any banned term as a literal substring (it would otherwise trip
// its own scan; the meta-test file is also excluded from the scan, but the
// self-test keeps the source clean for readability/searchability).
func TestLexiconMetaSelfTestTable(t *testing.T) {
	terms := lexicon.BannedTerms()
	// The spec lists 10 banned terms (plan docs say "9", counting dollar/euro
	// as a pair): bank, deposit, interest, yield, currency, dollar, euro,
	// account, savings, depositor.
	if len(terms) != 10 {
		t.Fatalf("BannedTerms() len = %d, want 10", len(terms))
	}
	// Each synthetic string embeds exactly one banned term in a plausible
	// sentence context. Each must be detected.
	synthetic := []string{
		"open a " + terms[0] + " here",      // bank
		"make a " + terms[1] + " now",       // deposit
		"compounding " + terms[2] + " rate", // interest
		"the " + terms[3] + " is 5pct",      // yield
		"foreign " + terms[4] + " pair",     // currency
		"price in " + terms[5],              // dollar
		"price in " + terms[6],              // euro
		"freeze the " + terms[7],            // account
		"move to " + terms[8] + " now",      // savings
		"the " + terms[9] + " lost money",   // depositor
	}
	if len(synthetic) != len(terms) {
		t.Fatalf("synthetic table len = %d, want %d", len(synthetic), len(terms))
	}
	for i, s := range synthetic {
		found, ok := lexicon.FindBannedTerm(s)
		if !ok {
			t.Errorf("G-009 self-test [%d]: synthetic string did not trigger detection: %q", i, s)
			continue
		}
		if found != terms[i] {
			t.Errorf("G-009 self-test [%d]: detected %q, want %q (in %q)", i, found, terms[i], s)
		}
	}
}

// TestLexiconMetaBannedTermsCount asserts exactly 10 banned terms are
// configured (locked-const for the firewall's scope; spec lists 10, plan docs
// say "9" counting dollar/euro as a pair).
func TestLexiconMetaBannedTermsCount(t *testing.T) {
	terms := lexicon.BannedTerms()
	if len(terms) != 10 {
		t.Errorf("BannedTerms() len = %d, want 10 (REQ-012)", len(terms))
	}
	seen := map[string]bool{}
	for _, tr := range terms {
		if seen[tr] {
			t.Errorf("duplicate banned term %q", tr)
		}
		seen[tr] = true
	}
}

// TestLexiconMetaNoFalsePositiveOnOpenYield asserts the module name
// "openyield" does NOT trigger the "yield" banned term (word-boundary
// matching must not match substrings of identifiers). This is the
// regression firewall for the word-boundary detection design.
func TestLexiconMetaNoFalsePositiveOnOpenYield(t *testing.T) {
	cases := []string{
		"github.com/oy/openyield/x/window/types",
		"package openyield",
		"openyield is the module",
		"european resident",
	}
	for _, s := range cases {
		if _, ok := lexicon.FindBannedTerm(s); ok {
			t.Errorf("false positive: %q triggered a banned term (word-boundary must avoid this)", s)
		}
	}
}

// repoXRoot returns the absolute path to the repo's x/ directory by walking
// up from this test file.
func repoXRoot(t *testing.T) string {
	t.Helper()
	_, file, _, ok := runtime.Caller(0)
	if !ok {
		t.Fatal("runtime.Caller failed")
	}
	// file = .../oy/lexicon_meta_test.go -> repo root is its dir; x/ is repo/x
	repoRoot := filepath.Dir(file)
	return filepath.Join(repoRoot, "x")
}

// thisFile returns the absolute path of this meta-test file (to exclude it
// from its own scan).
func thisFile(t *testing.T) string {
	t.Helper()
	_, file, _, ok := runtime.Caller(0)
	if !ok {
		t.Fatal("runtime.Caller failed")
	}
	return file
}