// TesseractOCR: three packages, a temp file, and manual byte conversion
// just to OCR one PDF page — before any preprocessing
// dotnet add package TesseractOCR
// dotnet add package Docnet.Core
// dotnet add package SixLabors.ImageSharp   (preprocessing)

using var library = DocLib.Instance;
using var docReader = library.GetDocReader(pdfPath, new PageDimensions(200, 200));
using var pageReader = docReader.GetPageReader(0);
var bytes = pageReader.GetImage(); // BGRA — not a format Pix.Image accepts directly

string tempPath = Path.GetTempFileName() + ".png";
SaveBgraAsPng(bytes, pageReader.GetPageWidth(), pageReader.GetPageHeight(), tempPath);
// ^ 30+ line helper method needed here

using var engine = new Engine(@"./tessdata", Language.English, EngineMode.Default);
using var image = TesseractOCR.Pix.Image.LoadFromFile(tempPath);
using var page = engine.Process(image);
string text = page.Text;
File.Delete(tempPath); // hope this succeeds

// TesseractOCR: three packages, a temp file, and manual byte conversion
// just to OCR one PDF page — before any preprocessing
// dotnet add package TesseractOCR
// dotnet add package Docnet.Core
// dotnet add package SixLabors.ImageSharp   (preprocessing)

using var library = DocLib.Instance;
using var docReader = library.GetDocReader(pdfPath, new PageDimensions(200, 200));
using var pageReader = docReader.GetPageReader(0);
var bytes = pageReader.GetImage(); // BGRA — not a format Pix.Image accepts directly

string tempPath = Path.GetTempFileName() + ".png";
SaveBgraAsPng(bytes, pageReader.GetPageWidth(), pageReader.GetPageHeight(), tempPath);
// ^ 30+ line helper method needed here

using var engine = new Engine(@"./tessdata", Language.English, EngineMode.Default);
using var image = TesseractOCR.Pix.Image.LoadFromFile(tempPath);
using var page = engine.Process(image);
string text = page.Text;
File.Delete(tempPath); // hope this succeeds

// IronOCR: one package, three lines, preprocessing automatic
// dotnet add package IronOcr

var ocr = new IronTesseract();
using var input = new OcrInput();
input.LoadPdf(pdfPath);
string text = ocr.Read(input).Text;

// IronOCR: one package, three lines, preprocessing automatic
// dotnet add package IronOcr

var ocr = new IronTesseract();
using var input = new OcrInput();
input.LoadPdf(pdfPath);
string text = ocr.Read(input).Text;

dotnet remove package TesseractOCR
dotnet remove package Docnet.Core
dotnet remove package SixLabors.ImageSharp

dotnet remove package TesseractOCR
dotnet remove package Docnet.Core
dotnet remove package SixLabors.ImageSharp

// Before (TesseractOCR)
using TesseractOCR;
using TesseractOCR.Enums;

// After (IronOCR)
using IronOcr;

// Before (TesseractOCR)
using TesseractOCR;
using TesseractOCR.Enums;

// After (IronOCR)
using IronOcr;

// Requires: dotnet add package SixLabors.ImageSharp
// Manual preprocessing — parameters must be tuned per document type
// Deskew is NOT in ImageSharp — requires custom Hough transform (~50-100 lines)

using SixLabors.ImageSharp;
using SixLabors.ImageSharp.Processing;
using TesseractOCR;
using TesseractOCR.Enums;

public string ExtractFromLowQualityScan(string imagePath)
{
    using var image = Image.Load(imagePath);

    image.Mutate(x => x.Grayscale());
    image.Mutate(x => x.Contrast(1.5f));          // manual tuning required
    image.Mutate(x => x.GaussianBlur(0.5f));      // noise reduction approximation
    image.Mutate(x => x.BinaryThreshold(0.5f));   // threshold requires per-doc adjustment

    // Deskew omitted — no built-in support, ~80 lines of additional code

    string tempPath = Path.GetTempFileName() + ".png";
    try
    {
        image.Save(tempPath);

        using var engine = new Engine(@"./tessdata", Language.English, EngineMode.Default);
        using var pix = TesseractOCR.Pix.Image.LoadFromFile(tempPath);
        using var page = engine.Process(pix);

        return page.Text;
    }
    finally
    {
        File.Delete(tempPath);
    }
}

// Requires: dotnet add package SixLabors.ImageSharp
// Manual preprocessing — parameters must be tuned per document type
// Deskew is NOT in ImageSharp — requires custom Hough transform (~50-100 lines)

using SixLabors.ImageSharp;
using SixLabors.ImageSharp.Processing;
using TesseractOCR;
using TesseractOCR.Enums;

public string ExtractFromLowQualityScan(string imagePath)
{
    using var image = Image.Load(imagePath);

    image.Mutate(x => x.Grayscale());
    image.Mutate(x => x.Contrast(1.5f));          // manual tuning required
    image.Mutate(x => x.GaussianBlur(0.5f));      // noise reduction approximation
    image.Mutate(x => x.BinaryThreshold(0.5f));   // threshold requires per-doc adjustment

    // Deskew omitted — no built-in support, ~80 lines of additional code

    string tempPath = Path.GetTempFileName() + ".png";
    try
    {
        image.Save(tempPath);

        using var engine = new Engine(@"./tessdata", Language.English, EngineMode.Default);
        using var pix = TesseractOCR.Pix.Image.LoadFromFile(tempPath);
        using var page = engine.Process(pix);

        return page.Text;
    }
    finally
    {
        File.Delete(tempPath);
    }
}

// Non external imaging library
// Non temp file — OcrInput accepts a path, stream, or byte array directly
// Deskew is built in — automatic angle detection and correction

using IronOcr;

public string ExtractFromLowQualityScan(string imagePath)
{
    using var input = new OcrInput();
    input.LoadImage(imagePath);
    input.Deskew();           // automatic angle correction
    input.DeNoise();          // intelligent noise removal
    input.Contrast();         // automatic contrast enhancement
    input.Binarize();         // clean black-and-white conversion

    var ocr = new IronTesseract();
    return ocr.Read(input).Text;
}

// Non external imaging library
// Non temp file — OcrInput accepts a path, stream, or byte array directly
// Deskew is built in — automatic angle detection and correction

using IronOcr;

public string ExtractFromLowQualityScan(string imagePath)
{
    using var input = new OcrInput();
    input.LoadImage(imagePath);
    input.Deskew();           // automatic angle correction
    input.DeNoise();          // intelligent noise removal
    input.Contrast();         // automatic contrast enhancement
    input.Binarize();         // clean black-and-white conversion

    var ocr = new IronTesseract();
    return ocr.Read(input).Text;
}

// Requires: dotnet add package SixLabors.ImageSharp
// Manual frame extraction — every frame becomes a temp file on disk

using SixLabors.ImageSharp;
using SixLabors.ImageSharp.Formats.Tiff;
using TesseractOCR;
using TesseractOCR.Enums;

public string ExtractFromMultiPageTiff(string tiffPath)
{
    var allText = new System.Text.StringBuilder();
    var tempFiles = new List<string>();

    try
    {
        using var image = Image.Load(tiffPath);
        using var engine = new Engine(@"./tessdata", Language.English, EngineMode.Default);

        for (int frameIndex = 0; frameIndex < image.Frames.Count; frameIndex++)
        {
            // Clone frame and save to temp file — no in-memory path
            using var frameImage = image.Frames.CloneFrame(frameIndex);
            string tempPath = Path.GetTempFileName() + ".png";
            tempFiles.Add(tempPath);
            frameImage.SaveAsPng(tempPath);

            using var pix = TesseractOCR.Pix.Image.LoadFromFile(tempPath);
            using var page = engine.Process(pix);

            allText.AppendLine($"=== Frame {frameIndex + 1} ===");
            allText.AppendLine(page.Text);
        }
    }
    finally
    {
        foreach (var f in tempFiles)
            try { File.Delete(f); } catch { }
    }

    return allText.ToString();
}

// Requires: dotnet add package SixLabors.ImageSharp
// Manual frame extraction — every frame becomes a temp file on disk

using SixLabors.ImageSharp;
using SixLabors.ImageSharp.Formats.Tiff;
using TesseractOCR;
using TesseractOCR.Enums;

public string ExtractFromMultiPageTiff(string tiffPath)
{
    var allText = new System.Text.StringBuilder();
    var tempFiles = new List<string>();

    try
    {
        using var image = Image.Load(tiffPath);
        using var engine = new Engine(@"./tessdata", Language.English, EngineMode.Default);

        for (int frameIndex = 0; frameIndex < image.Frames.Count; frameIndex++)
        {
            // Clone frame and save to temp file — no in-memory path
            using var frameImage = image.Frames.CloneFrame(frameIndex);
            string tempPath = Path.GetTempFileName() + ".png";
            tempFiles.Add(tempPath);
            frameImage.SaveAsPng(tempPath);

            using var pix = TesseractOCR.Pix.Image.LoadFromFile(tempPath);
            using var page = engine.Process(pix);

            allText.AppendLine($"=== Frame {frameIndex + 1} ===");
            allText.AppendLine(page.Text);
        }
    }
    finally
    {
        foreach (var f in tempFiles)
            try { File.Delete(f); } catch { }
    }

    return allText.ToString();
}

// Non external library for frame extraction
// All frames processed in one Read() call — no manual loop required

using IronOcr;

public string ExtractFromMultiPageTiff(string tiffPath)
{
    var ocr = new IronTesseract();
    using var input = new OcrInput();
    input.LoadImageFrames(tiffPath);   // loads all frames automatically
    var result = ocr.Read(input);

    // Access per-page text if needed
    foreach (var page in result.Pages)
        Console.WriteLine($"Frame {page.PageNumber}: {page.Text}");

    return result.Text;
}

// Non external library for frame extraction
// All frames processed in one Read() call — no manual loop required

using IronOcr;

public string ExtractFromMultiPageTiff(string tiffPath)
{
    var ocr = new IronTesseract();
    using var input = new OcrInput();
    input.LoadImageFrames(tiffPath);   // loads all frames automatically
    var result = ocr.Read(input);

    // Access per-page text if needed
    foreach (var page in result.Pages)
        Console.WriteLine($"Frame {page.PageNumber}: {page.Text}");

    return result.Text;
}

// Non path available — TesseractOCRcannot produce any PDF output.
// The closest workaround requires a separate PDF library (iTextSharp AGPL,
// or similar) to overlay extracted text onto the original PDF manually.
// This is 150-300 lines of additional code and introduces AGPL license concerns.

// The best available output from TesseractOCR:
using var engine = new Engine(@"./tessdata", Language.English, EngineMode.Default);
using var pix = TesseractOCR.Pix.Image.LoadFromFile("scanned-page.png");
using var page = engine.Process(pix);

string extractedText = page.Text; // flat string — no PDF output possible
File.WriteAllText("output.txt", extractedText);
// Cannot produce a searchable PDF — no API exists for this

// Non path available — TesseractOCRcannot produce any PDF output.
// The closest workaround requires a separate PDF library (iTextSharp AGPL,
// or similar) to overlay extracted text onto the original PDF manually.
// This is 150-300 lines of additional code and introduces AGPL license concerns.

// The best available output from TesseractOCR:
using var engine = new Engine(@"./tessdata", Language.English, EngineMode.Default);
using var pix = TesseractOCR.Pix.Image.LoadFromFile("scanned-page.png");
using var page = engine.Process(pix);

string extractedText = page.Text; // flat string — no PDF output possible
File.WriteAllText("output.txt", extractedText);
// Cannot produce a searchable PDF — no API exists for this

// Native searchable PDF output — no additional library required
// Input can be a scanned image, a scanned PDF, or a multi-page TIFF

using IronOcr;

public void CreateSearchablePdf(string scannedPdfPath, string outputPath)
{
    var ocr = new IronTesseract();
    using var input = new OcrInput();
    input.LoadPdf(scannedPdfPath);
    input.Deskew();     // improve accuracy before generating the output
    input.DeNoise();

    var result = ocr.Read(input);
    result.SaveAsSearchablePdf(outputPath);   // searchable, text-selectable PDF
}

// Native searchable PDF output — no additional library required
// Input can be a scanned image, a scanned PDF, or a multi-page TIFF

using IronOcr;

public void CreateSearchablePdf(string scannedPdfPath, string outputPath)
{
    var ocr = new IronTesseract();
    using var input = new OcrInput();
    input.LoadPdf(scannedPdfPath);
    input.Deskew();     // improve accuracy before generating the output
    input.DeNoise();

    var result = ocr.Read(input);
    result.SaveAsSearchablePdf(outputPath);   // searchable, text-selectable PDF
}

// TesseractOCR.Pix.Image has no byte[] or Stream overload
// Every in-memory image must be written to disk before processing

using TesseractOCR;
using TesseractOCR.Enums;

public string ExtractFromBytes(byte[] imageBytes)
{
    // Force a disk write just to satisfy the file-path API
    string tempPath = Path.GetTempFileName() + ".png";

    try
    {
        File.WriteAllBytes(tempPath, imageBytes);

        using var engine = new Engine(@"./tessdata", Language.English, EngineMode.Default);
        using var pix = TesseractOCR.Pix.Image.LoadFromFile(tempPath);
        using var page = engine.Process(pix);

        return page.Text;
    }
    finally
    {
        // Risk: if an exception fires between WriteAllBytes and Delete,
        // temp files accumulate on the server disk
        if (File.Exists(tempPath))
            File.Delete(tempPath);
    }
}

// TesseractOCR.Pix.Image has no byte[] or Stream overload
// Every in-memory image must be written to disk before processing

using TesseractOCR;
using TesseractOCR.Enums;

public string ExtractFromBytes(byte[] imageBytes)
{
    // Force a disk write just to satisfy the file-path API
    string tempPath = Path.GetTempFileName() + ".png";

    try
    {
        File.WriteAllBytes(tempPath, imageBytes);

        using var engine = new Engine(@"./tessdata", Language.English, EngineMode.Default);
        using var pix = TesseractOCR.Pix.Image.LoadFromFile(tempPath);
        using var page = engine.Process(pix);

        return page.Text;
    }
    finally
    {
        // Risk: if an exception fires between WriteAllBytes and Delete,
        // temp files accumulate on the server disk
        if (File.Exists(tempPath))
            File.Delete(tempPath);
    }
}

// OcrInput accepts byte arrays and streams natively
// Non disk write, no temp file cleanup, no cleanup failure risk

using IronOcr;

public string ExtractFromBytes(byte[] imageBytes)
{
    var ocr = new IronTesseract();
    using var input = new OcrInput();
    input.LoadImage(imageBytes);   // direct byte array — no temp file
    return ocr.Read(input).Text;
}

public string ExtractFromStream(Stream imageStream)
{
    var ocr = new IronTesseract();
    using var input = new OcrInput();
    input.LoadImage(imageStream);  // direct stream — no intermediate buffer
    return ocr.Read(input).Text;
}

// OcrInput accepts byte arrays and streams natively
// Non disk write, no temp file cleanup, no cleanup failure risk

using IronOcr;

public string ExtractFromBytes(byte[] imageBytes)
{
    var ocr = new IronTesseract();
    using var input = new OcrInput();
    input.LoadImage(imageBytes);   // direct byte array — no temp file
    return ocr.Read(input).Text;
}

public string ExtractFromStream(Stream imageStream)
{
    var ocr = new IronTesseract();
    using var input = new OcrInput();
    input.LoadImage(imageStream);  // direct stream — no intermediate buffer
    return ocr.Read(input).Text;
}

// Only document-level confidence available
// Non word coordinates, no structural hierarchy

using TesseractOCR;
using TesseractOCR.Enums;

public void ProcessWithConfidence(string imagePath)
{
    using var engine = new Engine(@"./tessdata", Language.English, EngineMode.Default);
    using var pix = TesseractOCR.Pix.Image.LoadFromFile(imagePath);
    using var page = engine.Process(pix);

    float docConfidence = page.MeanConfidence; // 0.0 to 1.0 for the whole document

    if (docConfidence >= 0.7f)
        Console.WriteLine($"Accepted ({docConfidence:P0}): {page.Text}");
    else
        Console.WriteLine($"Rejected ({docConfidence:P0}): document needs preprocessing");

    // Non way to identify WHICH words are uncertain
    // Non word coordinates available
}

// Only document-level confidence available
// Non word coordinates, no structural hierarchy

using TesseractOCR;
using TesseractOCR.Enums;

public void ProcessWithConfidence(string imagePath)
{
    using var engine = new Engine(@"./tessdata", Language.English, EngineMode.Default);
    using var pix = TesseractOCR.Pix.Image.LoadFromFile(imagePath);
    using var page = engine.Process(pix);

    float docConfidence = page.MeanConfidence; // 0.0 to 1.0 for the whole document

    if (docConfidence >= 0.7f)
        Console.WriteLine($"Accepted ({docConfidence:P0}): {page.Text}");
    else
        Console.WriteLine($"Rejected ({docConfidence:P0}): document needs preprocessing");

    // Non way to identify WHICH words are uncertain
    // Non word coordinates available
}

// Per-word confidence and coordinate data
// Filter individual uncertain words without discarding the whole document

using IronOcr;

public void ProcessWithWordLevelConfidence(string imagePath)
{
    var ocr = new IronTesseract();
    using var input = new OcrInput();
    input.LoadImage(imagePath);
    var result = ocr.Read(input);

    Console.WriteLine($"Document confidence: {result.Confidence}%");

    // Iterate words and flag those below threshold
    foreach (var page in result.Pages)
    {
        foreach (var word in page.Words)
        {
            if (word.Confidence < 70)
            {
                // Low-confidence word — log position for review
                Console.WriteLine(
                    $"Low confidence word '{word.Text}' ({word.Confidence}%) " +
                    $"at X:{word.X} Y:{word.Y}");
            }
        }
    }

    // Extract only high-confidence text
    var reliableWords = result.Pages
        .SelectMany(p => p.Words)
        .Where(w => w.Confidence >= 70)
        .Select(w => w.Text);

    Console.WriteLine(string.Join(" ", reliableWords));
}

// Per-word confidence and coordinate data
// Filter individual uncertain words without discarding the whole document

using IronOcr;

public void ProcessWithWordLevelConfidence(string imagePath)
{
    var ocr = new IronTesseract();
    using var input = new OcrInput();
    input.LoadImage(imagePath);
    var result = ocr.Read(input);

    Console.WriteLine($"Document confidence: {result.Confidence}%");

    // Iterate words and flag those below threshold
    foreach (var page in result.Pages)
    {
        foreach (var word in page.Words)
        {
            if (word.Confidence < 70)
            {
                // Low-confidence word — log position for review
                Console.WriteLine(
                    $"Low confidence word '{word.Text}' ({word.Confidence}%) " +
                    $"at X:{word.X} Y:{word.Y}");
            }
        }
    }

    // Extract only high-confidence text
    var reliableWords = result.Pages
        .SelectMany(p => p.Words)
        .Where(w => w.Confidence >= 70)
        .Select(w => w.Text);

    Console.WriteLine(string.Join(" ", reliableWords));
}

// Before (TesseractOCR): page.MeanConfidence >= 0.7f
// After (IronOCR):
var result = new IronTesseract().Read("document.png");
if (result.Confidence >= 70.0)
{
    Console.WriteLine(result.Text);
}

// Before (TesseractOCR): page.MeanConfidence >= 0.7f
// After (IronOCR):
var result = new IronTesseract().Read("document.png");
if (result.Confidence >= 70.0)
{
    Console.WriteLine(result.Text);
}

grep -rn "GetTempFileName\|GetTempPath\|SaveBgraAsPng" --include="*.cs" .

grep -rn "GetTempFileName\|GetTempPath\|SaveBgraAsPng" --include="*.cs" .

// Before: byte[] → temp file → Pix.Image.LoadFromFile
// After: byte[] → OcrInput directly
using var input = new OcrInput();
input.LoadImage(imageBytes);   // no disk write
var result = ocr.Read(input);

// Before: byte[] → temp file → Pix.Image.LoadFromFile
// After: byte[] → OcrInput directly
using var input = new OcrInput();
input.LoadImage(imageBytes);   // no disk write
var result = ocr.Read(input);

// Before (TesseractOCR):
var engine = new Engine(@"./tessdata",
    Language.English | Language.French | Language.German,
    EngineMode.Default);

// After (IronOCR):
var ocr = new IronTesseract();
ocr.Language = OcrLanguage.English + OcrLanguage.French + OcrLanguage.German;

// Before (TesseractOCR):
var engine = new Engine(@"./tessdata",
    Language.English | Language.French | Language.German,
    EngineMode.Default);

// After (IronOCR):
var ocr = new IronTesseract();
ocr.Language = OcrLanguage.English + OcrLanguage.French + OcrLanguage.German;

grep -rn "using Docnet\|using SixLabors\|using SkiaSharp" --include="*.cs" .

grep -rn "using Docnet\|using SixLabors\|using SkiaSharp" --include="*.cs" .

# Remove these lines after migration:
# RUN apt-get install -y tesseract-ocr tesseract-ocr-eng tesseract-ocr-fra
# COPY ./tessdata /app/tessdata

# Remove these lines after migration:
# RUN apt-get install -y tesseract-ocr tesseract-ocr-eng tesseract-ocr-fra
# COPY ./tessdata /app/tessdata

// Before: five exception types to handle
catch (TesseractOCR.Exceptions.TesseractException ex) { ... }
catch (DllNotFoundException ex) { ... }
catch (BadImageFormatException ex) { ... }
catch (OutOfMemoryException ex) { ... }

// After: two exception types
catch (IronOcr.Exceptions.OcrException ex) { ... }
catch (IOException ex) { ... }

// Before: five exception types to handle
catch (TesseractOCR.Exceptions.TesseractException ex) { ... }
catch (DllNotFoundException ex) { ... }
catch (BadImageFormatException ex) { ... }
catch (OutOfMemoryException ex) { ... }

// After: two exception types
catch (IronOcr.Exceptions.OcrException ex) { ... }
catch (IOException ex) { ... }

grep -rn "using TesseractOCR" --include="*.cs" .
grep -rn "new Engine(" --include="*.cs" .
grep -rn "Pix\.Image\.LoadFromFile\|engine\.Process\|page\.Text\|MeanConfidence" --include="*.cs" .
grep -rn "Language\." --include="*.cs" .

grep -rn "using TesseractOCR" --include="*.cs" .
grep -rn "new Engine(" --include="*.cs" .
grep -rn "Pix\.Image\.LoadFromFile\|engine\.Process\|page\.Text\|MeanConfidence" --include="*.cs" .
grep -rn "Language\." --include="*.cs" .

grep -rn "using Docnet\|using SixLabors\|GetTempFileName\|SaveBgraAsPng" --include="*.cs" .
grep -rn "tessdata" --include="*.cs" .
grep -rn "tessdata" --include="*.csproj" .
grep -rn "tessdata" Dockerfile 2>/dev/null || true

grep -rn "using Docnet\|using SixLabors\|GetTempFileName\|SaveBgraAsPng" --include="*.cs" .
grep -rn "tessdata" --include="*.cs" .
grep -rn "tessdata" --include="*.csproj" .
grep -rn "tessdata" Dockerfile 2>/dev/null || true