const std = @import("std");
const zfin = @import("../root.zig");
const cli = @import("common.zig");
const fmt = cli.fmt;

pub fn run(allocator: std.mem.Allocator, svc: *zfin.DataService, symbol: []const u8, ntm: usize, color: bool, out: *std.Io.Writer) !void {
    const result = svc.getOptions(symbol) catch |err| switch (err) {
        zfin.DataError.FetchFailed => {
            try cli.stderrPrint("Error fetching options data from CBOE.\n");
            return;
        },
        else => {
            try cli.stderrPrint("Error loading options data.\n");
            return;
        },
    };
    const ch = result.data;
    defer {
        for (ch) |chain| {
            allocator.free(chain.underlying_symbol);
            allocator.free(chain.calls);
            allocator.free(chain.puts);
        }
        allocator.free(ch);
    }

    if (result.source == .cached) try cli.stderrPrint("(using cached options data)\n");

    if (ch.len == 0) {
        try cli.stderrPrint("No options data found.\n");
        return;
    }

    try display(out, allocator, ch, symbol, ntm, color);
}

pub fn display(out: *std.Io.Writer, allocator: std.mem.Allocator, chains: []const zfin.OptionsChain, symbol: []const u8, ntm: usize, color: bool) !void {
    if (chains.len == 0) return;

    try cli.setBold(out, color);
    try out.print("\nOptions Chain for {s}\n", .{symbol});
    try cli.reset(out, color);
    try out.print("========================================\n", .{});
    if (chains[0].underlying_price) |price| {
        var price_buf: [24]u8 = undefined;
        try out.print("Underlying: {s}    {d} expiration(s)    +/- {d} strikes NTM\n", .{ fmt.fmtMoney(&price_buf, price), chains.len, ntm });
    } else {
        try out.print("{d} expiration(s) available\n", .{chains.len});
    }

    // Find nearest monthly expiration to auto-expand
    var auto_expand_idx: ?usize = null;
    for (chains, 0..) |chain, ci| {
        if (fmt.isMonthlyExpiration(chain.expiration)) {
            auto_expand_idx = ci;
            break;
        }
    }
    // If no monthly found, expand the first one
    if (auto_expand_idx == null and chains.len > 0) auto_expand_idx = 0;

    const atm_price = if (chains[0].underlying_price) |p| p else @as(f64, 0);

    // List all expirations, expanding the nearest monthly
    for (chains, 0..) |chain, ci| {
        var db: [10]u8 = undefined;
        const is_monthly = fmt.isMonthlyExpiration(chain.expiration);
        const is_expanded = auto_expand_idx != null and ci == auto_expand_idx.?;

        try out.print("\n", .{});
        if (is_expanded) {
            try cli.setBold(out, color);
            try out.print("{s}  ({d} calls, {d} puts)", .{
                chain.expiration.format(&db), chain.calls.len, chain.puts.len,
            });
            if (is_monthly) try out.print("  [monthly]", .{});
            try cli.reset(out, color);
            try out.print("\n", .{});

            // Print calls
            try printSection(out, allocator, "CALLS", chain.calls, atm_price, ntm, true, color);
            try out.print("\n", .{});
            // Print puts
            try printSection(out, allocator, "PUTS", chain.puts, atm_price, ntm, false, color);
        } else {
            try cli.setFg(out, color, if (is_monthly) cli.CLR_HEADER else cli.CLR_MUTED);
            try out.print("{s}  ({d} calls, {d} puts)", .{
                chain.expiration.format(&db), chain.calls.len, chain.puts.len,
            });
            if (is_monthly) try out.print("  [monthly]", .{});
            try cli.reset(out, color);
            try out.print("\n", .{});
        }
    }

    try out.print("\n", .{});
}

pub fn printSection(
    out: *std.Io.Writer,
    allocator: std.mem.Allocator,
    label: []const u8,
    contracts: []const zfin.OptionContract,
    atm_price: f64,
    ntm: usize,
    is_calls: bool,
    color: bool,
) !void {
    try cli.setBold(out, color);
    try out.print("    {s}\n", .{label});
    try cli.reset(out, color);
    try cli.setFg(out, color, cli.CLR_MUTED);
    try out.print("    {s:>10} {s:>10} {s:>10} {s:>10} {s:>10} {s:>8} {s:>8}\n", .{
        "Strike", "Last", "Bid", "Ask", "Volume", "OI", "IV",
    });
    try out.print("    {s:->10} {s:->10} {s:->10} {s:->10} {s:->10} {s:->8} {s:->8}\n", .{
        "", "", "", "", "", "", "",
    });
    try cli.reset(out, color);

    const filtered = fmt.filterNearMoney(contracts, atm_price, ntm);
    for (filtered) |c| {
        const itm = if (is_calls) c.strike <= atm_price else c.strike >= atm_price;
        const prefix: []const u8 = if (itm) "    |" else "     ";
        const line = try fmt.fmtContractLine(allocator, prefix, c);
        defer allocator.free(line);
        try out.print("{s}\n", .{line});
    }
}

// ── Tests ────────────────────────────────────────────────────

test "printSection shows header and contracts" {
    var buf: [8192]u8 = undefined;
    var w: std.Io.Writer = .fixed(&buf);
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    defer _ = gpa.deinit();
    const calls = [_]zfin.OptionContract{
        .{ .contract_type = .call, .strike = 150.0, .expiration = .{ .days = 20100 }, .bid = 5.0, .ask = 5.50, .last_price = 5.25 },
        .{ .contract_type = .call, .strike = 155.0, .expiration = .{ .days = 20100 }, .bid = 2.0, .ask = 2.50, .last_price = 2.25 },
    };
    try printSection(&w, gpa.allocator(), "CALLS", &calls, 152.0, 8, true, false);
    const out = w.buffered();
    try std.testing.expect(std.mem.indexOf(u8, out, "CALLS") != null);
    try std.testing.expect(std.mem.indexOf(u8, out, "Strike") != null);
    try std.testing.expect(std.mem.indexOf(u8, out, "\x1b[") == null);
}

test "display shows chain header no color" {
    var buf: [8192]u8 = undefined;
    var w: std.Io.Writer = .fixed(&buf);
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    defer _ = gpa.deinit();
    const calls = [_]zfin.OptionContract{};
    const puts = [_]zfin.OptionContract{};
    const chains = [_]zfin.OptionsChain{
        .{ .underlying_symbol = "SPY", .underlying_price = 500.0, .expiration = .{ .days = 20100 }, .calls = &calls, .puts = &puts },
    };
    try display(&w, gpa.allocator(), &chains, "SPY", 8, false);
    const out = w.buffered();
    try std.testing.expect(std.mem.indexOf(u8, out, "Options Chain for SPY") != null);
    try std.testing.expect(std.mem.indexOf(u8, out, "1 expiration(s)") != null);
    try std.testing.expect(std.mem.indexOf(u8, out, "\x1b[") == null);
}