package sync

// Manual repro harness for the CRE→CFI highlight conversion defects found in
// "Clean" (Rosser K Powitzky): 28 device highlights whose stored web CFIs are
// structurally inconsistent (mismatched start/end base paths, backwards
// ranges). This test mirrors handlers.convertHighlightPositions exactly —
// pos0 converted WITH the selection text as context, pos1 WITHOUT any — then
// reports the result alongside the CFIs stored at ingest time and a
// ground-truth oracle computed by locating the selection text in the document
// itself. Skips silently when the book/export are not on this machine, like
// cfi_verify_manual_test.go.

import (
	"fmt"
	"encoding/json"
	"os"
	"strings"
	"testing"

	"golang.org/x/net/html"
)

const (
	reproExport = "/home/nymusicman/Code/bookhoard/export/media_highlights.json"
	reproEpub   = "/home/nymusicman/Code/bookhoard/uploads/Ebooks/Rosser K Powitzky/Clean_ How the Jewish Roots of Atone (77)/Clean_ How the Jewish Roots of - Rosser K Powitzky.epub"
)

type reproRow struct {
	ID            string  `json:"id"`
	StartPosition string  `json:"start_position"`
	EndPosition   string  `json:"end_position"`
	StoredStart   string  `json:"epubcfi_start"`
	StoredEnd     string  `json:"epubcfi_end"`
	SelectionText string  `json:"selection_text"`
	PctStart      float64 `json:"percentage_start"`
}

// webUsable mirrors handlers.webUsableCFI (unexported there; cannot import
// the handlers package from here without a cycle).
func webUsable(precision, cfi string) string {
	if precision != "structural" && precision != "exact" {
		return ""
	}
	if !strings.HasPrefix(cfi, "epubcfi(") || !strings.HasSuffix(cfi, ")") {
		return ""
	}
	return cfi
}

// reproExtendCFIByLength mirrors handlers.extendCFIByLength: advance the
// trailing character offset of a point CFI by the UTF-16 length of text.
func reproExtendCFIByLength(cfi, text string) string {
	if cfi == "" || text == "" {
		return ""
	}
	if !strings.HasSuffix(cfi, ")") {
		return ""
	}
	inner := cfi[:len(cfi)-1]
	idx := strings.LastIndex(inner, ":")
	if idx < 0 {
		return cfi
	}
	var off int
	if _, err := fmtSscanInt(inner[idx+1:], &off); err != nil {
		return cfi
	}
	return inner[:idx+1] + itoa(off+utf16Len(text)) + ")"
}

// cfiBase splits "epubcfi(...)" into (base, offset): base is everything
// before the final ":N" character-offset terminator.
func cfiBase(cfi string) (string, int, bool) {
	if !strings.HasSuffix(cfi, ")") {
		return "", 0, false
	}
	inner := cfi[:len(cfi)-1]
	idx := strings.LastIndex(inner, ":")
	if idx < 0 {
		return inner, 0, true
	}
	off := 0
	if _, err := fmtSscanInt(inner[idx+1:], &off); err != nil {
		return inner, 0, true
	}
	return inner[:idx], off, true
}

func fmtSscanInt(s string, out *int) (int, error) {
	n := 0
	ok := false
	for _, r := range s {
		if r < '0' || r > '9' {
			break
		}
		n = n*10 + int(r-'0')
		ok = true
	}
	if !ok {
		return 0, errReproNoInt
	}
	*out = n
	return len(s), nil
}

var errReproNoInt = errReproNoIntErr{}

type errReproNoIntErr struct{}

func (errReproNoIntErr) Error() string { return "no integer" }

func itoa(n int) string {
	if n == 0 {
		return "0"
	}
	neg := n < 0
	if neg {
		n = -n
	}
	var b [20]byte
	i := len(b)
	for n > 0 {
		i--
		b[i] = byte('0' + n%10)
		n /= 10
	}
	if neg {
		i--
		b[i] = '-'
	}
	return string(b[i:])
}

// oracleCFIs locates the selection text in the document named by the start
// xpointer's fragment and returns ground-truth (startCFI, endCFI, spineIndex).
// Whitespace runs are collapsed on both sides before matching, so device
// text with reflowed newlines still lands.
func oracleCFIs(t *testing.T, conv *CFIConverter, row reproRow) (string, string, string) {
	xp, err := ParseCREXPointer(row.StartPosition)
	if err != nil {
		return "", "", "unparseable start xpointer"
	}
	doc, href, err := conv.getContentDoc(xp.FragmentIndex)
	if err != nil {
		return "", "", "content doc missing: " + err.Error()
	}
	body := findBody(doc)
	if body == nil {
		return "", "", "no body"
	}

	// Flatten every text node in document order.
	var segs []textSegment
	var walk func(*html.Node)
	walk = func(n *html.Node) {
		if n.Type == html.TextNode {
			segs = append(segs, textSegment{node: n, runes: []rune(n.Data)})
		}
		for c := n.FirstChild; c != nil; c = c.NextSibling {
			walk(c)
		}
	}
	walk(body)

	var flat []rune
	for _, s := range segs {
		flat = append(flat, s.runes...)
	}

	needle := []rune(normalizeWhitespace(row.SelectionText))
	if len(needle) == 0 {
		return "", "", "empty selection text"
	}
	// Collapse whitespace in `flat` while mapping each kept rune back to a
	// flat index.
	var norm []rune
	var normToFlat []int
	lastWS := false
	for i, r := range flat {
		isWS := r == ' ' || r == '\t' || r == '\n' || r == '\r' || r == ' ' || r == '​'
		if isWS {
			if lastWS {
				continue
			}
			norm = append(norm, ' ')
			normToFlat = append(normToFlat, i)
			lastWS = true
			continue
		}
		norm = append(norm, r)
		normToFlat = append(normToFlat, i)
		lastWS = false
	}

	// Trim wrapped-quote artifacts KOReader adds to partial-paragraph text.
	trimmed := needle
	for len(trimmed) > 0 && (trimmed[0] == '{' || trimmed[0] == '}') {
		trimmed = trimmed[1:]
	}
	for len(trimmed) > 0 && (trimmed[len(trimmed)-1] == '{' || trimmed[len(trimmed)-1] == '}') {
		trimmed = trimmed[:len(trimmed)-1]
	}

	pos := indexRunes(norm, trimmed)
	if pos < 0 {
		return "", "", "selection text not found in doc " + href
	}

	flatStart := normToFlat[pos]
	flatEnd := normToFlat[pos+len(trimmed)-1] + 1 // end is exclusive

	nodeAt := func(flatIdx int) (*html.Node, int) {
		acc := 0
		for _, s := range segs {
			n := len(s.runes)
			if flatIdx < acc+n {
				return s.node, flatIdx - acc
			}
			acc += n
		}
		return nil, 0
	}

	startNode, startOff := nodeAt(flatStart)
	endNode, endOff := nodeAt(flatEnd)
	if startNode == nil || endNode == nil {
		return "", "", "flat index out of range"
	}

	spineIndex := xp.FragmentIndex - 1
	startCFI, err := buildCFI(spineIndex, startNode, startOff)
	if err != nil {
		return "", "", "buildCFI start: " + err.Error()
	}
	endCFI, err := buildCFI(spineIndex, endNode, endOff)
	if err != nil {
		return "", "", "buildCFI end: " + err.Error()
	}
	return startCFI, endCFI, ""
}

func indexRunes(hay, needle []rune) int {
	if len(needle) == 0 || len(needle) > len(hay) {
		return -1
	}
	for i := 0; i+len(needle) <= len(hay); i++ {
		match := true
		for j := range needle {
			if hay[i+j] != needle[j] {
				match = false
				break
			}
		}
		if match {
			return i
		}
	}
	return -1
}

func TestManualCleanRepro(t *testing.T) {
	raw, err := os.ReadFile(reproExport)
	if err != nil {
		t.Skipf("export json not present: %v", err)
	}
	if _, err := os.Stat(reproEpub); err != nil {
		t.Skipf("book epub not present: %v", err)
	}
	var rows []reproRow
	if err := json.Unmarshal(raw, &rows); err != nil {
		t.Fatalf("unmarshal export: %v", err)
	}

	conv := cachedConverter(reproEpub)

	stats := map[string]int{}
	for _, row := range rows {
		// Mirror handlers.convertHighlightPositions (text-anchored primary
		// path, legacy per-endpoint fallback).
		startLoc := ConvertHighlightRangeToCanonical(reproEpub, "reflowable", row.StartPosition, row.EndPosition, row.SelectionText, row.PctStart)
		startCFI := webUsable(startLoc.Precision, startLoc.CFI)
		endCFI := ""
		if startCFI != "" && startLoc.EndCFI != "" {
			endCFI = webUsable(startLoc.Precision, startLoc.EndCFI)
		}
		if startCFI == "" {
			startLoc = ConvertToCanonical(LocatorSourceKOReader, row.StartPosition, row.PctStart, row.SelectionText, "reflowable", reproEpub, "")
			startCFI = webUsable(startLoc.Precision, startLoc.CFI)
			endCFI = ""
			if startCFI != "" && startLoc.EndCFI != "" {
				endCFI = startLoc.EndCFI
			}
			if endCFI == "" && row.EndPosition != "" {
				endLoc := ConvertToCanonical(LocatorSourceKOReader, row.EndPosition, row.PctStart, "", "reflowable", reproEpub, "")
				endCFI = webUsable(endLoc.Precision, endLoc.CFI)
			}
			if endCFI == "" && startCFI != "" && row.SelectionText != "" {
				endCFI = reproExtendCFIByLength(startCFI, row.SelectionText)
			}
		}

		oracleStart, oracleEnd, oracleNote := oracleCFIs(t, conv, row)
		stats["oracleMiss:"+statusOr(oracleNote)]++

		cls := func(a, b string) string {
			ba, oa, okA := cfiBase(a)
			bb, ob, okB := cfiBase(b)
			switch {
			case !okA || !okB || a == "" || b == "":
				return "missing"
			case ba != bb:
				return "diff-base"
			case ob <= oa:
				return "backwards"
			default:
				return "healthy"
			}
		}
		cur := cls(startCFI, endCFI)
		sto := cls(row.StoredStart, row.StoredEnd)
		ora := cls(oracleStart, oracleEnd)
		stats["current:"+cur]++
		stats["stored:"+sto]++
		stats["oracle:"+ora]++

		if os.Getenv("REPRO_VERBOSE") != "" || cur != "healthy" || sto != "healthy" {
			t.Logf("row %s", row.ID[:8])
			t.Logf("   raw:  %s  ->  %s", row.StartPosition, row.EndPosition)
			t.Logf("   ctx:  %q", truncateRunes(row.SelectionText, 60))
			t.Logf("   stored:   %-38s %-38s [%s]", row.StoredStart, row.StoredEnd, sto)
			t.Logf("   current:  %-38s %-38s [%s]", startCFI, endCFI, cur)
			t.Logf("   oracle:   %-38s %-38s [%s] %s", oracleStart, oracleEnd, ora, oracleNote)
		}
	}

	t.Logf("summary: %v", stats)

	// REPRO_EMIT_SQL=<path>: emit UPDATE statements carrying the NEW
	// converter output into the database rows this export came from
	// (one-off healing of rows written by the broken converter).
	if out := os.Getenv("REPRO_EMIT_SQL"); out != "" {
		var b strings.Builder
		b.WriteString("BEGIN;\n")
		for _, row := range rows {
			startLoc := ConvertHighlightRangeToCanonical(reproEpub, "reflowable", row.StartPosition, row.EndPosition, row.SelectionText, row.PctStart)
			startCFI := webUsable(startLoc.Precision, startLoc.CFI)
			endCFI := ""
			if startCFI != "" && startLoc.EndCFI != "" {
				endCFI = webUsable(startLoc.Precision, startLoc.EndCFI)
			}
			if startCFI == "" {
				continue // leave untouched; legacy fallback rows keep old CFIs
			}
			b.WriteString(fmt.Sprintf(
				"UPDATE media_highlights SET epubcfi_start=%s, epubcfi_end=%s WHERE id='%s';\n",
				pgQuote(startCFI), pgQuote(endCFI), row.ID,
			))
		}
		b.WriteString("COMMIT;\n")
		if err := os.WriteFile(out, []byte(b.String()), 0o600); err != nil {
			t.Fatalf("write sql: %v", err)
		}
		t.Logf("wrote %s", out)
	}
}

func pgQuote(s string) string {
	if s == "" {
		return "''"
	}
	return "'" + strings.ReplaceAll(s, "'", "''") + "'"
}

func statusOr(s string) string {
	if s == "" {
		return "found"
	}
	return s
}