#ifndef CHAT_BLOCK_MODEL_H
#define CHAT_BLOCK_MODEL_H

#include <QAbstractListModel>
#include <QList>
#include <QString>

// A single block in the chat output
struct ChatBlock {
    enum Type {
        User,       // [user] markdown
        Assistant,  // [assistant] markdown
        Reasoning,  // [reasoning] content
        Call,       // [call:name] args
        Tool,       // [tool:name] output
        Error,      // [error] text
        Info        // [info] text
    };

    Type type;
    QString name;       // tool/call name, empty for others
    QString responseId; // stable assistant response ID
    QString reaction;   // emoji reaction text (empty if not reacted)
    QString content;    // raw text content
    mutable QVariantList cachedSubBlocks; // cached parseSubBlocks result
    mutable QString cachedContent;        // content when subBlocks were cached
};

// A sub-block within a markdown block (prose, code fence, diff)
struct ContentBlock {
    enum Type {
        Prose,      // regular markdown text
        Code,       // fenced code block
        Diff,       // unified diff (detected by content pattern)
        Diagram     // mermaid/plantuml rendered as image
    };

    Type type;
    QString language; // for Code and Diagram blocks
    QString content;
};

class ChatBlockModel : public QAbstractListModel
{
    Q_OBJECT
    Q_PROPERTY(QString rawText READ rawText WRITE setRawText NOTIFY rawTextChanged)
    Q_PROPERTY(QString filterText READ filterText WRITE setFilterText NOTIFY filterTextChanged)
    Q_PROPERTY(bool filtering READ filtering NOTIFY filterTextChanged)

public:
    enum Roles {
        BlockTypeRole = Qt::UserRole + 1,
        NameRole,
        ContentRole,
        SubBlocksRole,  // QVariantList of sub-block maps
        FormattedContentRole, // pre-formatted HTML for call/tool expanded view
        ResponseIdRole,
        ReactionRole,
    };

    explicit ChatBlockModel(QObject *parent = nullptr);

    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
    QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
    QHash<int, QByteArray> roleNames() const override;

    QString rawText() const { return m_rawText; }
    void setRawText(const QString &text);

    QString filterText() const { return m_filterText; }
    void setFilterText(const QString &text);
    bool filtering() const { return !m_filterText.isEmpty(); }

    Q_INVOKABLE QString highlightedHtml(const QString &code, const QString &language) const;
    Q_INVOKABLE QString prettyJson(const QString &text) const;
    Q_INVOKABLE void copyToClipboard(const QString &text) const;
    Q_INVOKABLE QString linkifyFilePaths(const QString &markdown) const;
    Q_INVOKABLE void openLink(const QString &link) const;
    Q_INVOKABLE bool executeInTerminal(const QString &code, const QString &language,
                                       const QString &workingDirectory = QString()) const;
    Q_INVOKABLE bool loadEarlier(); // returns true if more blocks were loaded
    Q_INVOKABLE void setReactions(const QVariantMap &reactions);
    Q_INVOKABLE QString diagramUrl(const QString &source, const QString &language) const;
    Q_INVOKABLE bool invalidateDiagram(const QString &source, const QString &language) const;

signals:
    void rawTextChanged();
    void filterTextChanged();

private:
    void reparse();
    void updateVisibleWindow();
    void applyFilter();
    QList<ChatBlock> parseBlocks(const QString &text) const;
    QVariantList parseSubBlocks(const QString &content) const;

    QString m_rawText;
    QString m_filterText;
    QList<ChatBlock> m_allBlocks;   // all parsed blocks
    QList<ChatBlock> m_blocks;      // visible window (tail of m_allBlocks)
    QList<ChatBlock> m_filteredBlocks; // filtered subset when filterText is active
    int m_visibleStart = 0;         // index into m_allBlocks where visible window starts
    mutable QHash<QString, QString> m_highlightCache;
};

#endif // CHAT_BLOCK_MODEL_H