const std = @import("std");
const vaxis = @import("vaxis");
const zfin = @import("../root.zig");
const fmt = @import("../format.zig");
const theme = @import("theme.zig");
const tui = @import("../tui.zig");

const App = tui.App;
const StyledLine = tui.StyledLine;

// ── Data loading ──────────────────────────────────────────────

pub fn loadData(app: *App) void {
    app.options_loaded = true;
    app.freeOptions();

    const result = app.svc.getOptions(app.symbol) catch |err| {
        switch (err) {
            zfin.DataError.FetchFailed => app.setStatus("CBOE fetch failed (network error)"),
            else => app.setStatus("Error loading options"),
        }
        return;
    };
    app.options_data = result.data;
    app.options_timestamp = result.timestamp;
    app.options_cursor = 0;
    app.options_expanded = @splat(false);
    app.options_calls_collapsed = @splat(false);
    app.options_puts_collapsed = @splat(false);
    app.rebuildOptionsRows();
    app.setStatus(if (result.source == .cached) "Cached (1hr TTL) | r/F5 to refresh" else "Fetched | r/F5 to refresh");
}

// ── Rendering ─────────────────────────────────────────────────

pub fn buildStyledLines(app: *App, arena: std.mem.Allocator) ![]const StyledLine {
    const th = app.theme;
    var lines: std.ArrayList(StyledLine) = .empty;

    try lines.append(arena, .{ .text = "", .style = th.contentStyle() });

    if (app.symbol.len == 0) {
        try lines.append(arena, .{ .text = "  No symbol selected. Press / to enter a symbol.", .style = th.mutedStyle() });
        return lines.toOwnedSlice(arena);
    }

    const chains = app.options_data orelse {
        try lines.append(arena, .{ .text = "  Loading options data...", .style = th.mutedStyle() });
        return lines.toOwnedSlice(arena);
    };

    if (chains.len == 0) {
        try lines.append(arena, .{ .text = "  No options data found.", .style = th.mutedStyle() });
        return lines.toOwnedSlice(arena);
    }

    var opt_ago_buf: [16]u8 = undefined;
    // wall-clock required: per-frame "now" for the "refreshed Xs ago"
    // readout. Captured here rather than on `app` so it refreshes every
    // time this tab renders.
    const now_s = std.Io.Timestamp.now(app.io, .real).toSeconds();
    const opt_ago = fmt.fmtTimeAgo(&opt_ago_buf, app.options_timestamp, now_s);
    if (opt_ago.len > 0) {
        try lines.append(arena, .{ .text = try std.fmt.allocPrint(arena, "  Options: {s}  (data {s}, 15 min delay)", .{ app.symbol, opt_ago }), .style = th.headerStyle() });
    } else {
        try lines.append(arena, .{ .text = try std.fmt.allocPrint(arena, "  Options: {s}", .{app.symbol}), .style = th.headerStyle() });
    }

    if (chains[0].underlying_price) |price| {
        var price_buf: [24]u8 = undefined;
        try lines.append(arena, .{ .text = try std.fmt.allocPrint(arena, "  Underlying: {s}    {d} expiration(s)    +/- {d} strikes NTM (Ctrl+1-9 to change)", .{ fmt.fmtMoneyAbs(&price_buf, price), chains.len, app.options_near_the_money }), .style = th.contentStyle() });
    }

    try lines.append(arena, .{ .text = "", .style = th.contentStyle() });

    // Track header line count for mouse click mapping (after all non-data lines)
    app.options_header_lines = lines.items.len;

    // Flat list of options rows with inline expand/collapse
    for (app.options_rows.items, 0..) |row, ri| {
        const is_cursor = ri == app.options_cursor;
        switch (row.kind) {
            .expiration => {
                if (row.exp_idx < chains.len) {
                    const chain = chains[row.exp_idx];
                    var db: [10]u8 = undefined;
                    const is_expanded = row.exp_idx < app.options_expanded.len and app.options_expanded[row.exp_idx];
                    const is_monthly = fmt.isMonthlyExpiration(chain.expiration);
                    const arrow: []const u8 = if (is_expanded) "v " else "> ";
                    const text = try std.fmt.allocPrint(arena, "  {s}{s}  ({d} calls, {d} puts)", .{
                        arrow,
                        chain.expiration.format(&db),
                        chain.calls.len,
                        chain.puts.len,
                    });
                    const style = if (is_cursor) th.selectStyle() else if (is_monthly) th.contentStyle() else th.mutedStyle();
                    try lines.append(arena, .{ .text = text, .style = style });
                }
            },
            .calls_header => {
                const calls_collapsed = row.exp_idx < app.options_calls_collapsed.len and app.options_calls_collapsed[row.exp_idx];
                const arrow: []const u8 = if (calls_collapsed) "    > " else "    v ";
                const style = if (is_cursor) th.selectStyle() else th.headerStyle();
                try lines.append(arena, .{ .text = try std.fmt.allocPrint(arena, "{s}{s:>10} {s:>10} {s:>10} {s:>10} {s:>10} {s:>8} {s:>8}  Calls", .{
                    arrow, "Strike", "Last", "Bid", "Ask", "Volume", "OI", "IV",
                }), .style = style });
            },
            .puts_header => {
                const puts_collapsed = row.exp_idx < app.options_puts_collapsed.len and app.options_puts_collapsed[row.exp_idx];
                const arrow: []const u8 = if (puts_collapsed) "    > " else "    v ";
                try lines.append(arena, .{ .text = "", .style = th.contentStyle() });
                const style = if (is_cursor) th.selectStyle() else th.headerStyle();
                try lines.append(arena, .{ .text = try std.fmt.allocPrint(arena, "{s}{s:>10} {s:>10} {s:>10} {s:>10} {s:>10} {s:>8} {s:>8}  Puts", .{
                    arrow, "Strike", "Last", "Bid", "Ask", "Volume", "OI", "IV",
                }), .style = style });
            },
            .call => {
                if (row.contract) |cc| {
                    const atm_price = chains[0].underlying_price orelse 0;
                    const itm = cc.strike <= atm_price;
                    const prefix: []const u8 = if (itm) "      |" else "       ";
                    var contract_buf: [128]u8 = undefined;
                    const text = try arena.dupe(u8, fmt.fmtContractLine(&contract_buf, prefix, cc));
                    const style = if (is_cursor) th.selectStyle() else th.contentStyle();
                    try lines.append(arena, .{ .text = text, .style = style });
                }
            },
            .put => {
                if (row.contract) |p| {
                    const atm_price = chains[0].underlying_price orelse 0;
                    const itm = p.strike >= atm_price;
                    const prefix: []const u8 = if (itm) "      |" else "       ";
                    var contract_buf: [128]u8 = undefined;
                    const text = try arena.dupe(u8, fmt.fmtContractLine(&contract_buf, prefix, p));
                    const style = if (is_cursor) th.selectStyle() else th.contentStyle();
                    try lines.append(arena, .{ .text = text, .style = style });
                }
            },
        }
    }

    return lines.toOwnedSlice(arena);
}