//! Interactive list demo for zcatui.
//!
//! Demonstrates a navigable list with keyboard controls.
//! - Up/Down or j/k: Navigate items
//! - Enter: Select item
//! - q/ESC: Quit
//!
//! Run with: zig build list-demo

const std = @import("std");
const zcatui = @import("zcatui");

const Terminal = zcatui.Terminal;
const Buffer = zcatui.Buffer;
const Rect = zcatui.Rect;
const Style = zcatui.Style;
const Color = zcatui.Color;
const Event = zcatui.Event;
const KeyCode = zcatui.KeyCode;
const Layout = zcatui.Layout;
const Constraint = zcatui.Constraint;
const Block = zcatui.widgets.Block;
const Borders = zcatui.widgets.Borders;
const List = zcatui.widgets.List;
const ListItem = zcatui.widgets.ListItem;
const ListState = zcatui.widgets.ListState;

const items = [_][]const u8{
    "Item 1 - First item in the list",
    "Item 2 - Second item",
    "Item 3 - Third item",
    "Item 4 - Fourth item",
    "Item 5 - Fifth item",
    "Item 6 - Sixth item",
    "Item 7 - Seventh item",
    "Item 8 - Eighth item",
    "Item 9 - Ninth item",
    "Item 10 - Tenth item",
};

const AppState = struct {
    list_state: ListState,
    selected_item: ?usize = null,
    running: bool = true,

    fn init() AppState {
        return .{
            .list_state = ListState.default,
        };
    }

    fn nextItem(self: *AppState) void {
        const current = self.list_state.selected orelse 0;
        if (current < items.len - 1) {
            self.list_state.selected = current + 1;
        }
    }

    fn prevItem(self: *AppState) void {
        const current = self.list_state.selected orelse 0;
        if (current > 0) {
            self.list_state.selected = current - 1;
        }
    }

    fn selectCurrent(self: *AppState) void {
        self.selected_item = self.list_state.selected;
    }
};

pub fn main() !void {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    defer _ = gpa.deinit();
    const allocator = gpa.allocator();

    var term = try Terminal.init(allocator);
    defer term.deinit();

    var state = AppState.init();
    state.list_state.selected = 0; // Start with first item selected

    while (state.running) {
        try term.drawWithContext(&state, render);

        if (try term.pollEvent(100)) |event| {
            handleEvent(&state, event);
        }
    }
}

fn handleEvent(state: *AppState, event: Event) void {
    switch (event) {
        .key => |key| {
            switch (key.code) {
                .esc => state.running = false,
                .char => |c| {
                    switch (c) {
                        'q', 'Q' => state.running = false,
                        'j' => state.nextItem(),
                        'k' => state.prevItem(),
                        else => {},
                    }
                },
                .down => state.nextItem(),
                .up => state.prevItem(),
                .enter => state.selectCurrent(),
                else => {},
            }
        },
        else => {},
    }
}

fn render(state: *AppState, area: Rect, buf: *Buffer) void {
    // Layout: list on left, info on right
    const chunks = Layout.horizontal(&.{
        Constraint.percentage(60),
        Constraint.percentage(40),
    }).split(area);

    // Render list
    renderList(state, chunks.get(0), buf);

    // Render info panel
    renderInfo(state, chunks.get(1), buf);
}

fn renderList(state: *AppState, area: Rect, buf: *Buffer) void {
    // Create list items
    var list_items: [items.len]ListItem = undefined;
    for (items, 0..) |item, i| {
        list_items[i] = ListItem.raw(item);
    }

    const list = List.init(&list_items)
        .setBlock(Block.init()
        .title(" Items (j/k or arrows) ")
        .setBorders(Borders.all)
        .style(Style.default.fg(Color.cyan)))
        .highlightStyle(Style.default.fg(Color.black).bg(Color.cyan))
        .highlightSymbol("> ");

    list.renderStateful(area, buf, &state.list_state);
}

fn renderInfo(state: *AppState, area: Rect, buf: *Buffer) void {
    const info_block = Block.init()
        .title(" Info ")
        .setBorders(Borders.all)
        .style(Style.default.fg(Color.yellow));
    info_block.render(area, buf);

    const inner = info_block.inner(area);
    var y = inner.top();

    // Selected index
    var idx_buf: [32]u8 = undefined;
    const idx_str = if (state.list_state.selected) |sel|
        std.fmt.bufPrint(&idx_buf, "Index: {d}", .{sel}) catch "?"
    else
        "Index: none";
    _ = buf.setString(inner.left(), y, idx_str, Style.default);
    y += 2;

    // Last selected item
    _ = buf.setString(inner.left(), y, "Last selected:", Style.default.bold());
    y += 1;

    if (state.selected_item) |sel| {
        if (sel < items.len) {
            _ = buf.setString(inner.left(), y, items[sel], Style.default.fg(Color.green));
        }
    } else {
        _ = buf.setString(inner.left(), y, "(press Enter)", Style.default.fg(Color.white));
    }
    y += 3;

    // Help
    _ = buf.setString(inner.left(), y, "Controls:", Style.default.bold());
    y += 1;
    _ = buf.setString(inner.left(), y, "Up/k   - Previous", Style.default);
    y += 1;
    _ = buf.setString(inner.left(), y, "Down/j - Next", Style.default);
    y += 1;
    _ = buf.setString(inner.left(), y, "Enter  - Select", Style.default);
    y += 1;
    _ = buf.setString(inner.left(), y, "q/ESC  - Quit", Style.default);
}