Lumacs/include/lumacs/buffer.hpp

#pragma once

#include <string>
#include <vector>
#include <optional>
#include <filesystem>
#include <memory>

namespace lumacs {

/// Represents a cursor position in a buffer
struct Position {
    size_t line;
    size_t column;

    auto operator<=>(const Position&) const = default;
};

/// Represents a range in the buffer
struct Range {
    Position start;
    Position end;

    auto operator<=>(const Range&) const = default;
};

/// A text buffer that manages the content of a file or scratch buffer
class Buffer {
public:
    /// Create an empty buffer
    Buffer();

    /// Create a buffer with a name (for scratch buffers)
    explicit Buffer(std::string name);

    /// Create a buffer from a file
    static std::optional<Buffer> from_file(const std::filesystem::path& path);

    // Disable copy, allow move
    Buffer(const Buffer&) = delete;
    Buffer& operator=(const Buffer&) = delete;
    Buffer(Buffer&&) noexcept = default;
    Buffer& operator=(Buffer&&) noexcept = default;

    ~Buffer() = default;

    // === Content Access ===

    /// Get the number of lines in the buffer
    [[nodiscard]] size_t line_count() const noexcept;

    /// Get a line by index (0-based)
    [[nodiscard]] const std::string& line(size_t index) const;

    /// Get all lines
    [[nodiscard]] const std::vector<std::string>& lines() const noexcept;

    /// Get the entire buffer content as a single string
    [[nodiscard]] std::string content() const;

    // === Modification ===

    /// Insert text at a position
    void insert(Position pos, std::string_view text);

    /// Insert a character at a position
    void insert_char(Position pos, char c);

    /// Insert a newline at a position
    void insert_newline(Position pos);

    /// Delete a range of text
    void erase(Range range);

    /// Delete a character at a position (backspace)
    void erase_char(Position pos);

    /// Replace text in a range
    void replace(Range range, std::string_view text);

    /// Clear the entire buffer
    void clear();

    // === File Operations ===

    /// Save the buffer to its associated file
    bool save();

    /// Save the buffer to a specific file
    bool save_as(const std::filesystem::path& path);

    /// Check if the buffer has been modified since last save
    [[nodiscard]] bool is_modified() const noexcept;

    /// Get the file path associated with this buffer (if any)
    [[nodiscard]] std::optional<std::filesystem::path> file_path() const noexcept;

    // === Buffer Properties ===

    /// Get the buffer name
    [[nodiscard]] const std::string& name() const noexcept;

    /// Set the buffer name
    void set_name(std::string name);

    /// Check if position is valid
    [[nodiscard]] bool is_valid_position(Position pos) const noexcept;

    /// Clamp a position to valid bounds
    [[nodiscard]] Position clamp_position(Position pos) const noexcept;

private:
    std::string name_;
    std::vector<std::string> lines_;
    std::optional<std::filesystem::path> file_path_;
    bool modified_;

    /// Ensure the buffer has at least one line
    void ensure_min_lines();

    /// Mark the buffer as modified
    void mark_modified();
};

} // namespace lumacs