//! OpenFIGI API provider -- maps CUSIPs (and other identifiers) to ticker symbols.
//! API docs: https://www.openfigi.com/api/documentation
//!
//! Free tier: 25 requests/minute with API key (each request can contain up to 100 jobs).
//! No API key required for basic use (lower rate limits).
//!
//! Note: OpenFIGI does NOT cover most mutual funds (especially institutional/401(k) share
//! classes). For those, use the `ticker::` alias field in the portfolio SRF file.

const std = @import("std");

const api_url = "https://api.openfigi.com/v3/mapping";

/// Result of a CUSIP lookup.
pub const FigiResult = struct {
    ticker: ?[]const u8,
    name: ?[]const u8,
    security_type: ?[]const u8,
    /// Whether the API returned a valid response (even if no match was found)
    found: bool,
};

/// Look up a single CUSIP via OpenFIGI. Caller must free returned strings.
/// Returns null ticker if not found. Uses system curl for the POST request.
pub fn lookupCusip(
    allocator: std.mem.Allocator,
    cusip: []const u8,
    api_key: ?[]const u8,
) !FigiResult {
    const results = try lookupCusips(allocator, &.{cusip}, api_key);
    defer {
        for (results) |r| {
            if (r.ticker) |t| allocator.free(t);
            if (r.name) |n| allocator.free(n);
            if (r.security_type) |s| allocator.free(s);
        }
        allocator.free(results);
    }
    if (results.len == 0) return .{ .ticker = null, .name = null, .security_type = null, .found = false };

    // Copy results since we're freeing the batch
    const r = results[0];
    return .{
        .ticker = if (r.ticker) |t| try allocator.dupe(u8, t) else null,
        .name = if (r.name) |n| try allocator.dupe(u8, n) else null,
        .security_type = if (r.security_type) |s| try allocator.dupe(u8, s) else null,
        .found = r.found,
    };
}

/// Look up multiple CUSIPs in a single batch request. Caller owns all returned slices.
/// Results array is parallel to the input cusips array (same length, same order).
pub fn lookupCusips(
    allocator: std.mem.Allocator,
    cusips: []const []const u8,
    api_key: ?[]const u8,
) ![]FigiResult {
    if (cusips.len == 0) return try allocator.alloc(FigiResult, 0);

    // Build JSON request body: [{"idType":"ID_CUSIP","idValue":"..."},...]
    var body_buf: std.ArrayList(u8) = .empty;
    defer body_buf.deinit(allocator);

    try body_buf.append(allocator, '[');
    for (cusips, 0..) |cusip, i| {
        if (i > 0) try body_buf.append(allocator, ',');
        try body_buf.appendSlice(allocator, "{\"idType\":\"ID_CUSIP\",\"idValue\":\"");
        try body_buf.appendSlice(allocator, cusip);
        try body_buf.appendSlice(allocator, "\"}");
    }
    try body_buf.append(allocator, ']');

    const body_str = body_buf.items;

    // Build curl command
    var argv_buf: [12][]const u8 = undefined;
    var argc: usize = 0;
    argv_buf[argc] = "curl";
    argc += 1;
    argv_buf[argc] = "-sS";
    argc += 1;
    argv_buf[argc] = "-f";
    argc += 1;
    argv_buf[argc] = "--max-time";
    argc += 1;
    argv_buf[argc] = "30";
    argc += 1;
    argv_buf[argc] = "-X";
    argc += 1;
    argv_buf[argc] = "POST";
    argc += 1;
    argv_buf[argc] = "-H";
    argc += 1;
    argv_buf[argc] = "Content-Type: application/json";
    argc += 1;
    if (api_key) |key| {
        // Build header string: "X-OPENFIGI-APIKEY: <key>"
        const hdr = try std.fmt.allocPrint(allocator, "X-OPENFIGI-APIKEY: {s}", .{key});
        defer allocator.free(hdr);
        argv_buf[argc] = "-H";
        argc += 1;
        argv_buf[argc] = hdr;
        argc += 1;
        argv_buf[argc] = "-d";
        argc += 1;

        // Need to add body and URL — but we've used all slots for the -H key header.
        // Restructure: use a dynamic list.
        var argv_list: std.ArrayList([]const u8) = .empty;
        defer argv_list.deinit(allocator);
        try argv_list.appendSlice(allocator, &.{
            "curl", "-sS", "--max-time", "30",
            "-X",   "POST",
            "-H",   "Content-Type: application/json",
            "-H",   hdr,
            "-d",   body_str,
            api_url,
        });

        const result = std.process.Child.run(.{
            .allocator = allocator,
            .argv = argv_list.items,
            .max_output_bytes = 1 * 1024 * 1024,
        }) catch return error.RequestFailed;
        defer allocator.free(result.stderr);

        const success = switch (result.term) {
            .Exited => |code| code == 0,
            else => false,
        };
        if (!success) {
            allocator.free(result.stdout);
            return error.RequestFailed;
        }
        return parseResponse(allocator, result.stdout, cusips.len);
    } else {
        // No API key
        var argv_list: std.ArrayList([]const u8) = .empty;
        defer argv_list.deinit(allocator);
        try argv_list.appendSlice(allocator, &.{
            "curl", "-sS", "--max-time", "30",
            "-X",   "POST",
            "-H",   "Content-Type: application/json",
            "-d",   body_str,
            api_url,
        });

        const result = std.process.Child.run(.{
            .allocator = allocator,
            .argv = argv_list.items,
            .max_output_bytes = 1 * 1024 * 1024,
        }) catch return error.RequestFailed;
        defer allocator.free(result.stderr);

        const success = switch (result.term) {
            .Exited => |code| code == 0,
            else => false,
        };
        if (!success) {
            allocator.free(result.stdout);
            return error.RequestFailed;
        }
        return parseResponse(allocator, result.stdout, cusips.len);
    }
}

fn parseResponse(allocator: std.mem.Allocator, body: []const u8, expected_count: usize) ![]FigiResult {
    defer allocator.free(body);

    const parsed = std.json.parseFromSlice(std.json.Value, allocator, body, .{}) catch
        return error.ParseError;
    defer parsed.deinit();

    const root = parsed.value;
    const arr = switch (root) {
        .array => |a| a,
        else => return error.ParseError,
    };

    var results = try allocator.alloc(FigiResult, expected_count);
    for (results) |*r| r.* = .{ .ticker = null, .name = null, .security_type = null, .found = false };

    for (arr.items, 0..) |item, i| {
        if (i >= expected_count) break;

        const obj = switch (item) {
            .object => |o| o,
            else => continue,
        };

        // Check for error/warning (no match)
        if (obj.get("warning") != null or obj.get("error") != null) {
            results[i].found = true; // API responded, just no match
            continue;
        }

        // Get the data array
        const data = switch (obj.get("data") orelse continue) {
            .array => |a| a,
            else => continue,
        };

        if (data.items.len == 0) {
            results[i].found = true;
            continue;
        }

        // Use the first result, preferring exchCode "US" if available
        var best: ?std.json.ObjectMap = null;
        for (data.items) |entry| {
            const entry_obj = switch (entry) {
                .object => |o| o,
                else => continue,
            };
            if (best == null) best = entry_obj;
            // Prefer US exchange
            if (entry_obj.get("exchCode")) |ec| {
                if (ec == .string and std.mem.eql(u8, ec.string, "US")) {
                    best = entry_obj;
                    break;
                }
            }
        }

        if (best) |b| {
            results[i].found = true;
            if (b.get("ticker")) |t| {
                if (t == .string and t.string.len > 0) {
                    results[i].ticker = try allocator.dupe(u8, t.string);
                }
            }
            if (b.get("name")) |n| {
                if (n == .string and n.string.len > 0) {
                    results[i].name = try allocator.dupe(u8, n.string);
                }
            }
            if (b.get("securityType")) |st| {
                if (st == .string and st.string.len > 0) {
                    results[i].security_type = try allocator.dupe(u8, st.string);
                }
            }
        }
    }

    return results;
}

/// Check if a string looks like a CUSIP (9 alphanumeric characters).
/// CUSIPs have 6 alphanumeric issuer chars + 2 issue chars + 1 check digit.
/// This is a heuristic — it won't catch all CUSIPs and may have false positives.
pub fn isCusipLike(s: []const u8) bool {
    if (s.len != 9) return false;
    // Must contain at least one digit (all-alpha would be a ticker)
    var has_digit = false;
    for (s) |c| {
        if (!std.ascii.isAlphanumeric(c)) return false;
        if (std.ascii.isDigit(c)) has_digit = true;
    }
    return has_digit;
}

test "isCusipLike" {
    try std.testing.expect(isCusipLike("02315N600")); // Vanguard Target 2035
    try std.testing.expect(isCusipLike("02315N709")); // Vanguard Target 2040
    try std.testing.expect(isCusipLike("459200101")); // IBM
    try std.testing.expect(isCusipLike("06051XJ45")); // CD CUSIP
    try std.testing.expect(!isCusipLike("AAPL")); // Too short
    try std.testing.expect(!isCusipLike("ABCDEFGHI")); // No digits
    try std.testing.expect(isCusipLike("NON40OR52")); // Looks cusip-like (has digits, 9 chars)
    try std.testing.expect(!isCusipLike("12345")); // Too short
}