#pragma once

#include "core/result.h"
#include "ui/macro_expander.h"

#include <cstdint>
#include <filesystem>
#include <optional>
#include <string>
#include <unordered_set>
#include <vector>

struct ImDrawList;
struct ImFont;

namespace Hsdbg
{
    class Debugger;

    // one coloured run inside a source line; start and length index into the
    // line's own string so the spans stay valid as long as the line does
    enum class SyntaxKind : uint8_t
    {
        Default,
        Keyword,
        Type,
        String,
        Number,
        Comment,
        Preprocessor,
        Macro,
    };

    struct SourceSpan
    {
        uint32_t start;
        uint32_t length;
        SyntaxKind kind;
    };

    class SourceView
    {
    public:
        auto open(const std::filesystem::path& file_path) -> Result<void>;
        auto close() -> void;

        auto draw(Debugger& debugger) -> void;

        auto set_highlighted_line(uint32_t line) -> void;

        // the lines of the function the selected frame is in (zero for unknown):
        // live values are only annotated inside it
        auto set_frame_extent(uint32_t first, uint32_t last) -> void;

        // names of locals that moved since the previous stop; their annotations
        // take the accent. the set is owned by the caller and read each frame
        auto set_changed_locals(const std::unordered_set<std::string>* names) -> void { m_changed_locals = names; }
        auto set_highlighting(bool enabled) -> void { m_highlighting_enabled = enabled; }
        auto set_line_numbers(bool enabled) -> void { m_line_numbers = enabled; }
        auto set_highlight_current_line(bool enabled) -> void { m_highlight_current_line = enabled; }

        // packed ImU32 (0xAABBGGRR) colours, one per SyntaxKind, index 0 unused
        auto set_syntax_color(size_t kind, unsigned int color) -> void { m_syntax_colors[kind] = color; }
        auto set_current_line_color(unsigned int color) -> void { m_current_line_color = color; }

        // the monospace face the code (and its gutter) is rendered in, and its
        // size in px before ui scaling: cmd/ctrl + wheel over the code nudges the
        // size, and the ui reads it back to persist it
        auto set_mono_font(ImFont* font) -> void { m_mono_font = font; }
        auto set_font_size(float size) -> void { m_font_size = size; }
        auto font_size() const -> float { return m_font_size; }

        auto path() const -> const std::filesystem::path& { return m_path; }
        auto line_count() const -> size_t { return m_lines.size(); }
        auto is_open() const -> bool { return !m_lines.empty(); }

        // the #defines visible in the open file, so a panel can expand the same
        // macros the source view is highlighting
        auto macros() const -> const MacroTable& { return m_macros; }

        // when the user clicks a highlighted macro, the invocation as written
        // (name plus any argument list) is stashed here for the ui to pick up and
        // hand to the macros panel; cleared once taken
        auto take_macro_request() -> std::optional<std::string>;

        // right-clicking a name in the source stashes it here for the ui to add to
        // the watch list; cleared once taken
        auto take_watch_request() -> std::optional<std::string>;

    private:
        auto draw_open_bar() -> void;
        auto draw_lines(Debugger& debugger) -> void;
        auto handle_zoom() -> void;

        // renders a highlighted macro name: hovering previews its expansion,
        // clicking records the invocation for the macros panel to open
        auto draw_macro_span(ImDrawList* draw_list, const std::string& line,
                             const SourceSpan& span) -> void;

        ImFont* m_mono_font = nullptr;
        std::filesystem::path m_path;
        std::vector<std::string> m_lines;
        std::vector<std::vector<SourceSpan>> m_spans;
        MacroTable m_macros;
        std::optional<std::string> m_macro_request;
        std::optional<std::string> m_watch_request;
        bool m_highlight = false;
        bool m_highlighting_enabled = true;
        bool m_line_numbers = true;
        bool m_highlight_current_line = true;

        // indexed by SyntaxKind; the defaults match the built-in dark palette.
        // the macro colour (last) is warm on purpose so expandable names read as
        // clickable against the rest of the syntax
        unsigned int m_syntax_colors[8] = {
            0, 0xFFD69C56, 0xFFB0C94E, 0xFF7891CE, 0xFFA8CEB5, 0xFF55996A, 0xFFC086C5,
            0xFF4FA3E0,
        };
        unsigned int m_current_line_color = 0xFF2E483A;
        std::string m_path_input;
        std::string m_error;
        uint32_t m_highlighted_line = 0;
        bool m_scroll_to_highlight = false;

        // the location bar shows the open path as a breadcrumb; a click swaps in
        // the text field (and asks for its focus) until a file opens or it loses focus
        bool m_editing_path = false;
        bool m_focus_path = false;

        float m_font_size = 16.0f;
        float m_zoom_accumulator = 0.0f; // wheel travel not yet turned into a step
        double m_zoom_badge_until = 0.0; // the "NN px" badge shows until this time

        uint32_t m_frame_first_line = 0;
        uint32_t m_frame_last_line = 0;
        const std::unordered_set<std::string>* m_changed_locals = nullptr;
    };
}