const std = @import("std");
const Allocator = std.mem.Allocator;
const input = @import("../../input.zig");
const CircBuf = @import("../../datastruct/main.zig").CircBuf;
const cimgui = @import("dcimgui");

/// Circular buffer of key events.
pub const EventRing = CircBuf(Event, undefined);

/// Represents a recorded keyboard event.
pub const Event = struct {
    /// The input event.
    event: input.KeyEvent,

    /// The binding that was triggered as a result of this event.
    /// Multiple bindings are possible if they are chained.
    binding: []const input.Binding.Action = &.{},

    /// The data sent to the pty as a result of this keyboard event.
    /// This is allocated using the inspector allocator.
    pty: []const u8 = "",

    /// State for the inspector GUI. Do not set this unless you're the inspector.
    imgui_state: struct {
        selected: bool = false,
    } = .{},

    pub fn init(alloc: Allocator, ev: input.KeyEvent) !Event {
        var copy = ev;
        copy.utf8 = "";
        if (ev.utf8.len > 0) copy.utf8 = try alloc.dupe(u8, ev.utf8);
        return .{ .event = copy };
    }

    pub fn deinit(self: *const Event, alloc: Allocator) void {
        alloc.free(self.binding);
        if (self.event.utf8.len > 0) alloc.free(self.event.utf8);
        if (self.pty.len > 0) alloc.free(self.pty);
    }

    /// Returns a label that can be used for this event. This is null-terminated
    /// so it can be easily used with C APIs.
    pub fn label(self: *const Event, buf: []u8) ![:0]const u8 {
        var buf_stream = std.io.fixedBufferStream(buf);
        const writer = buf_stream.writer();

        switch (self.event.action) {
            .press => try writer.writeAll("Press: "),
            .release => try writer.writeAll("Release: "),
            .repeat => try writer.writeAll("Repeat: "),
        }

        if (self.event.mods.shift) try writer.writeAll("Shift+");
        if (self.event.mods.ctrl) try writer.writeAll("Ctrl+");
        if (self.event.mods.alt) try writer.writeAll("Alt+");
        if (self.event.mods.super) try writer.writeAll("Super+");

        // Write our key. If we have an invalid key we attempt to write
        // the utf8 associated with it if we have it to handle non-ascii.
        try writer.writeAll(switch (self.event.key) {
            .unidentified => if (self.event.utf8.len > 0) self.event.utf8 else @tagName(self.event.key),
            else => @tagName(self.event.key),
        });

        // Deadkey
        if (self.event.composing) try writer.writeAll(" (composing)");

        // Null-terminator
        try writer.writeByte(0);
        return buf[0..(buf_stream.getWritten().len - 1) :0];
    }

    /// Render this event in the inspector GUI.
    pub fn render(self: *const Event) void {
        _ = cimgui.c.ImGui_BeginTable(
            "##event",
            2,
            cimgui.c.ImGuiTableFlags_None,
        );
        defer cimgui.c.ImGui_EndTable();

        if (self.binding.len > 0) {
            cimgui.c.ImGui_TableNextRow();
            _ = cimgui.c.ImGui_TableSetColumnIndex(0);
            cimgui.c.ImGui_Text("Triggered Binding");
            _ = cimgui.c.ImGui_TableSetColumnIndex(1);

            const height: f32 = height: {
                const item_count: f32 = @floatFromInt(@min(self.binding.len, 5));
                const padding = cimgui.c.ImGui_GetStyle().*.FramePadding.y * 2;
                break :height cimgui.c.ImGui_GetTextLineHeightWithSpacing() * item_count + padding;
            };
            if (cimgui.c.ImGui_BeginListBox("##bindings", .{ .x = 0, .y = height })) {
                defer cimgui.c.ImGui_EndListBox();
                for (self.binding) |action| {
                    _ = cimgui.c.ImGui_SelectableEx(
                        @tagName(action).ptr,
                        false,
                        cimgui.c.ImGuiSelectableFlags_None,
                        .{ .x = 0, .y = 0 },
                    );
                }
            }
        }

        pty: {
            cimgui.c.ImGui_TableNextRow();
            _ = cimgui.c.ImGui_TableSetColumnIndex(0);
            cimgui.c.ImGui_Text("Encoding to Pty");
            _ = cimgui.c.ImGui_TableSetColumnIndex(1);
            if (self.pty.len == 0) {
                cimgui.c.ImGui_TextDisabled("(no data)");
                break :pty;
            }

            self.renderPty() catch {
                cimgui.c.ImGui_TextDisabled("(error rendering pty data)");
                break :pty;
            };
        }

        {
            cimgui.c.ImGui_TableNextRow();
            _ = cimgui.c.ImGui_TableSetColumnIndex(0);
            cimgui.c.ImGui_Text("Action");
            _ = cimgui.c.ImGui_TableSetColumnIndex(1);
            cimgui.c.ImGui_Text("%s", @tagName(self.event.action).ptr);
        }
        {
            cimgui.c.ImGui_TableNextRow();
            _ = cimgui.c.ImGui_TableSetColumnIndex(0);
            cimgui.c.ImGui_Text("Key");
            _ = cimgui.c.ImGui_TableSetColumnIndex(1);
            cimgui.c.ImGui_Text("%s", @tagName(self.event.key).ptr);
        }
        if (!self.event.mods.empty()) {
            cimgui.c.ImGui_TableNextRow();
            _ = cimgui.c.ImGui_TableSetColumnIndex(0);
            cimgui.c.ImGui_Text("Mods");
            _ = cimgui.c.ImGui_TableSetColumnIndex(1);
            if (self.event.mods.shift) cimgui.c.ImGui_Text("shift ");
            if (self.event.mods.ctrl) cimgui.c.ImGui_Text("ctrl ");
            if (self.event.mods.alt) cimgui.c.ImGui_Text("alt ");
            if (self.event.mods.super) cimgui.c.ImGui_Text("super ");
        }
        if (self.event.composing) {
            cimgui.c.ImGui_TableNextRow();
            _ = cimgui.c.ImGui_TableSetColumnIndex(0);
            cimgui.c.ImGui_Text("Composing");
            _ = cimgui.c.ImGui_TableSetColumnIndex(1);
            cimgui.c.ImGui_Text("true");
        }
        utf8: {
            cimgui.c.ImGui_TableNextRow();
            _ = cimgui.c.ImGui_TableSetColumnIndex(0);
            cimgui.c.ImGui_Text("UTF-8");
            _ = cimgui.c.ImGui_TableSetColumnIndex(1);
            if (self.event.utf8.len == 0) {
                cimgui.c.ImGui_TextDisabled("(empty)");
                break :utf8;
            }

            self.renderUtf8(self.event.utf8) catch {
                cimgui.c.ImGui_TextDisabled("(error rendering utf-8)");
                break :utf8;
            };
        }
    }

    fn renderUtf8(self: *const Event, utf8: []const u8) !void {
        _ = self;

        // Format the codepoint sequence
        var buf: [1024]u8 = undefined;
        var buf_stream = std.io.fixedBufferStream(&buf);
        const writer = buf_stream.writer();
        if (std.unicode.Utf8View.init(utf8)) |view| {
            var it = view.iterator();
            while (it.nextCodepoint()) |cp| {
                try writer.print("U+{X} ", .{cp});
            }
        } else |_| {
            try writer.writeAll("(invalid utf-8)");
        }
        try writer.writeByte(0);

        // Render as a textbox
        _ = cimgui.c.ImGui_InputText(
            "##utf8",
            &buf,
            buf_stream.getWritten().len - 1,
            cimgui.c.ImGuiInputTextFlags_ReadOnly,
        );
    }

    fn renderPty(self: *const Event) !void {
        // Format the codepoint sequence
        var buf: [1024]u8 = undefined;
        var buf_stream = std.io.fixedBufferStream(&buf);
        const writer = buf_stream.writer();

        for (self.pty) |byte| {
            // Print ESC special because its so common
            if (byte == 0x1B) {
                try writer.writeAll("ESC ");
                continue;
            }

            // Print ASCII as-is
            if (byte > 0x20 and byte < 0x7F) {
                try writer.writeByte(byte);
                continue;
            }

            // Everything else as a hex byte
            try writer.print("0x{X} ", .{byte});
        }

        try writer.writeByte(0);

        // Render as a textbox
        _ = cimgui.c.ImGui_InputText(
            "##pty",
            &buf,
            buf_stream.getWritten().len - 1,
            cimgui.c.ImGuiInputTextFlags_ReadOnly,
        );
    }
};

fn modsTooltip(
    mods: *const input.Mods,
    buf: []u8,
) ![:0]const u8 {
    var writer: std.Io.Writer = .fixed(buf);
    var first = true;
    if (mods.shift) {
        try writer.writeAll("Shift");
        first = false;
    }
    if (mods.ctrl) {
        if (!first) try writer.writeAll("+");
        try writer.writeAll("Ctrl");
        first = false;
    }
    if (mods.alt) {
        if (!first) try writer.writeAll("+");
        try writer.writeAll("Alt");
        first = false;
    }
    if (mods.super) {
        if (!first) try writer.writeAll("+");
        try writer.writeAll("Super");
    }
    try writer.writeByte(0);
    const written = writer.buffered();
    return written[0 .. written.len - 1 :0];
}

/// Keyboard event stream inspector widget.
pub const Stream = struct {
    events: EventRing,

    pub fn init(alloc: Allocator) !Stream {
        var events: EventRing = try .init(alloc, 2);
        errdefer events.deinit(alloc);
        return .{ .events = events };
    }

    pub fn deinit(self: *Stream, alloc: Allocator) void {
        var it = self.events.iterator(.forward);
        while (it.next()) |v| v.deinit(alloc);
        self.events.deinit(alloc);
    }

    pub fn draw(
        self: *Stream,
        open: bool,
        alloc: Allocator,
    ) void {
        if (!open) return;

        if (self.events.empty()) {
            cimgui.c.ImGui_Text("No recorded key events. Press a key with the " ++
                "terminal focused to record it.");
            return;
        }

        if (cimgui.c.ImGui_Button("Clear")) {
            var it = self.events.iterator(.forward);
            while (it.next()) |v| v.deinit(alloc);
            self.events.clear();
        }

        cimgui.c.ImGui_Separator();

        const table_flags = cimgui.c.ImGuiTableFlags_Borders |
            cimgui.c.ImGuiTableFlags_Resizable |
            cimgui.c.ImGuiTableFlags_ScrollY |
            cimgui.c.ImGuiTableFlags_SizingFixedFit;

        if (!cimgui.c.ImGui_BeginTable("table_key_events", 6, table_flags)) return;
        defer cimgui.c.ImGui_EndTable();

        cimgui.c.ImGui_TableSetupScrollFreeze(0, 1);
        cimgui.c.ImGui_TableSetupColumnEx("Action", cimgui.c.ImGuiTableColumnFlags_WidthFixed, 80, 0);
        cimgui.c.ImGui_TableSetupColumnEx("Key", cimgui.c.ImGuiTableColumnFlags_WidthFixed, 160, 0);
        cimgui.c.ImGui_TableSetupColumnEx("Mods", cimgui.c.ImGuiTableColumnFlags_WidthFixed, 150, 0);
        cimgui.c.ImGui_TableSetupColumnEx("UTF-8", cimgui.c.ImGuiTableColumnFlags_WidthFixed, 80, 0);
        cimgui.c.ImGui_TableSetupColumnEx("PTY Encoding", cimgui.c.ImGuiTableColumnFlags_WidthStretch, 0, 0);
        cimgui.c.ImGui_TableSetupColumnEx("Binding", cimgui.c.ImGuiTableColumnFlags_WidthStretch, 0, 0);
        cimgui.c.ImGui_TableHeadersRow();

        var it = self.events.iterator(.reverse);
        while (it.next()) |ev| {
            cimgui.c.ImGui_PushIDPtr(ev);
            defer cimgui.c.ImGui_PopID();

            cimgui.c.ImGui_TableNextRow();
            const row_min_y = cimgui.c.ImGui_GetCursorScreenPos().y;

            // Set row background color based on action
            cimgui.c.ImGui_TableSetBgColor(cimgui.c.ImGuiTableBgTarget_RowBg0, actionColor(ev.event.action), -1);

            // Action column with colored text
            _ = cimgui.c.ImGui_TableSetColumnIndex(0);
            const action_text_color: cimgui.c.ImVec4 = switch (ev.event.action) {
                .press => .{ .x = 0.4, .y = 1.0, .z = 0.4, .w = 1.0 }, // Green
                .release => .{ .x = 0.6, .y = 0.6, .z = 1.0, .w = 1.0 }, // Blue
                .repeat => .{ .x = 1.0, .y = 1.0, .z = 0.4, .w = 1.0 }, // Yellow
            };
            cimgui.c.ImGui_TextColored(action_text_color, "%s", @tagName(ev.event.action).ptr);

            // Key column with consistent key coloring
            _ = cimgui.c.ImGui_TableSetColumnIndex(1);
            const key_name = switch (ev.event.key) {
                .unidentified => if (ev.event.utf8.len > 0) ev.event.utf8 else @tagName(ev.event.key),
                else => @tagName(ev.event.key),
            };
            const key_rgba = keyColor(ev.event.key);
            const key_color: cimgui.c.ImVec4 = .{
                .x = @as(f32, @floatFromInt(key_rgba & 0xFF)) / 255.0,
                .y = @as(f32, @floatFromInt((key_rgba >> 8) & 0xFF)) / 255.0,
                .z = @as(f32, @floatFromInt((key_rgba >> 16) & 0xFF)) / 255.0,
                .w = 1.0,
            };
            cimgui.c.ImGui_TextColored(key_color, "%s", key_name.ptr);

            // Composing indicator
            if (ev.event.composing) {
                cimgui.c.ImGui_SameLine();
                cimgui.c.ImGui_TextColored(.{ .x = 1.0, .y = 0.6, .z = 0.0, .w = 1.0 }, "*");
                if (cimgui.c.ImGui_IsItemHovered(cimgui.c.ImGuiHoveredFlags_None)) {
                    cimgui.c.ImGui_SetTooltip("Composing (dead key)");
                }
            }

            // Mods
            _ = cimgui.c.ImGui_TableSetColumnIndex(2);
            mods: {
                if (ev.event.mods.empty()) {
                    cimgui.c.ImGui_TextDisabled("-");
                    break :mods;
                }

                var any_hovered = false;
                if (ev.event.mods.shift) {
                    _ = cimgui.c.ImGui_SmallButton("S");
                    any_hovered = any_hovered or cimgui.c.ImGui_IsItemHovered(cimgui.c.ImGuiHoveredFlags_None);
                    cimgui.c.ImGui_SameLine();
                }
                if (ev.event.mods.ctrl) {
                    _ = cimgui.c.ImGui_SmallButton("C");
                    any_hovered = any_hovered or cimgui.c.ImGui_IsItemHovered(cimgui.c.ImGuiHoveredFlags_None);
                    cimgui.c.ImGui_SameLine();
                }
                if (ev.event.mods.alt) {
                    _ = cimgui.c.ImGui_SmallButton("A");
                    any_hovered = any_hovered or cimgui.c.ImGui_IsItemHovered(cimgui.c.ImGuiHoveredFlags_None);
                    cimgui.c.ImGui_SameLine();
                }
                if (ev.event.mods.super) {
                    _ = cimgui.c.ImGui_SmallButton("M");
                    any_hovered = any_hovered or cimgui.c.ImGui_IsItemHovered(cimgui.c.ImGuiHoveredFlags_None);
                    cimgui.c.ImGui_SameLine();
                }
                cimgui.c.ImGui_NewLine();

                if (any_hovered) tooltip: {
                    var tooltip_buf: [64]u8 = undefined;
                    const tooltip = modsTooltip(
                        &ev.event.mods,
                        &tooltip_buf,
                    ) catch break :tooltip;
                    cimgui.c.ImGui_SetTooltip("%s", tooltip.ptr);
                }
            }

            // UTF-8
            _ = cimgui.c.ImGui_TableSetColumnIndex(3);
            if (ev.event.utf8.len == 0) {
                cimgui.c.ImGui_TextDisabled("-");
            } else {
                var utf8_buf: [128]u8 = undefined;
                var utf8_writer: std.Io.Writer = .fixed(&utf8_buf);
                if (std.unicode.Utf8View.init(ev.event.utf8)) |view| {
                    var utf8_it = view.iterator();
                    while (utf8_it.nextCodepoint()) |cp| {
                        utf8_writer.print("U+{X} ", .{cp}) catch break;
                    }
                } else |_| {
                    utf8_writer.writeAll("?") catch {};
                }
                utf8_writer.writeByte(0) catch {};
                cimgui.c.ImGui_Text("%s", &utf8_buf);
            }

            // PTY
            _ = cimgui.c.ImGui_TableSetColumnIndex(4);
            if (ev.pty.len == 0) {
                cimgui.c.ImGui_TextDisabled("-");
            } else {
                var pty_buf: [256]u8 = undefined;
                var pty_writer: std.Io.Writer = .fixed(&pty_buf);
                for (ev.pty) |byte| {
                    if (byte == 0x1B) {
                        pty_writer.writeAll("ESC ") catch break;
                    } else if (byte > 0x20 and byte < 0x7F) {
                        pty_writer.writeByte(byte) catch break;
                    } else {
                        pty_writer.print("0x{X} ", .{byte}) catch break;
                    }
                }
                pty_writer.writeByte(0) catch {};
                cimgui.c.ImGui_Text("%s", &pty_buf);
            }

            // Binding
            _ = cimgui.c.ImGui_TableSetColumnIndex(5);
            if (ev.binding.len == 0) {
                cimgui.c.ImGui_TextDisabled("-");
            } else {
                var binding_buf: [256]u8 = undefined;
                var binding_writer: std.Io.Writer = .fixed(&binding_buf);
                for (ev.binding, 0..) |action, i| {
                    if (i > 0) binding_writer.writeAll(", ") catch break;
                    binding_writer.writeAll(@tagName(action)) catch break;
                }
                binding_writer.writeByte(0) catch {};
                cimgui.c.ImGui_Text("%s", &binding_buf);
            }

            // Row hover highlight
            const row_max_y = cimgui.c.ImGui_GetCursorScreenPos().y;
            const mouse_pos = cimgui.c.ImGui_GetMousePos();
            if (mouse_pos.y >= row_min_y and mouse_pos.y < row_max_y) {
                cimgui.c.ImGui_TableSetBgColor(cimgui.c.ImGuiTableBgTarget_RowBg1, 0x1AFFFFFF, -1);
            }
        }
    }
};

/// Returns row background color for an action (ABGR format for ImGui)
fn actionColor(action: input.Action) u32 {
    return switch (action) {
        .press => 0x1A4A6F4A, // Muted sage green
        .release => 0x1A6A5A5A, // Muted slate gray
        .repeat => 0x1A4A5A6F, // Muted warm brown
    };
}

/// Generate a consistent color for a key based on its enum value.
/// Uses HSV color space with fixed saturation and value for pleasing colors.
fn keyColor(key: input.Key) u32 {
    const key_int: u32 = @intCast(@intFromEnum(key));
    const hue: f32 = @as(f32, @floatFromInt(key_int *% 47)) / 256.0;
    return hsvToRgba(hue, 0.5, 0.9, 1.0);
}

/// Convert HSV (hue 0-1, saturation 0-1, value 0-1) to RGBA u32.
fn hsvToRgba(h: f32, s: f32, v: f32, a: f32) u32 {
    var r: f32 = undefined;
    var g: f32 = undefined;
    var b: f32 = undefined;

    const i: u32 = @intFromFloat(h * 6.0);
    const f = h * 6.0 - @as(f32, @floatFromInt(i));
    const p = v * (1.0 - s);
    const q = v * (1.0 - f * s);
    const t = v * (1.0 - (1.0 - f) * s);

    switch (i % 6) {
        0 => {
            r = v;
            g = t;
            b = p;
        },
        1 => {
            r = q;
            g = v;
            b = p;
        },
        2 => {
            r = p;
            g = v;
            b = t;
        },
        3 => {
            r = p;
            g = q;
            b = v;
        },
        4 => {
            r = t;
            g = p;
            b = v;
        },
        else => {
            r = v;
            g = p;
            b = q;
        },
    }

    const ri: u32 = @intFromFloat(r * 255.0);
    const gi: u32 = @intFromFloat(g * 255.0);
    const bi: u32 = @intFromFloat(b * 255.0);
    const ai: u32 = @intFromFloat(a * 255.0);

    return (ai << 24) | (bi << 16) | (gi << 8) | ri;
}
