const std = @import("std");

// Source-patched coding symbol rail table.
// req: input/003, governance/001, testing/001, testing/002, testing/003, testing/004

test {
    _ = lookup;
}

pub const Symbol = enum {
    parens,
    brackets,
    braces,
    slash,
    line_comment,
    star,
    ampersand,
    hash,
    dollar,
    at,
    pipe,
    double_quote,
    single_quote,
    backtick,
    underscore,
};

pub const Entry = struct {
    key: []const u8,
    symbol: Symbol,
    label: []const u8,
    protocol_command: []const u8,
};

pub const entries = [_]Entry{
    .{ .key = "p", .symbol = .parens, .label = "()", .protocol_command = "command pair parens" },
    .{ .key = "b", .symbol = .brackets, .label = "[]", .protocol_command = "command pair brackets" },
    .{ .key = "c", .symbol = .braces, .label = "{}", .protocol_command = "command pair braces" },
    .{ .key = "s", .symbol = .slash, .label = "/", .protocol_command = "command insert /" },
    .{ .key = "f", .symbol = .line_comment, .label = "//", .protocol_command = "command insert //" },
    .{ .key = "x", .symbol = .star, .label = "*", .protocol_command = "command insert *" },
    .{ .key = "a", .symbol = .ampersand, .label = "&", .protocol_command = "command insert &" },
    .{ .key = "h", .symbol = .hash, .label = "#", .protocol_command = "command insert #" },
    .{ .key = "d", .symbol = .dollar, .label = "$", .protocol_command = "command insert $" },
    .{ .key = "r", .symbol = .at, .label = "@", .protocol_command = "command insert @" },
    .{ .key = "v", .symbol = .pipe, .label = "|", .protocol_command = "command insert |" },
    .{ .key = "q", .symbol = .double_quote, .label = "\"\"", .protocol_command = "command pair double_quote" },
    .{ .key = "e", .symbol = .single_quote, .label = "''", .protocol_command = "command pair single_quote" },
    .{ .key = "t", .symbol = .backtick, .label = "``", .protocol_command = "command pair backtick" },
    .{ .key = "u", .symbol = .underscore, .label = "_", .protocol_command = "command insert _" },
};

pub const rail_status = "symbols: p ()  b []  c {}  s /  f //  x *  a &  h #  d $  r @  v |  q \"\"  e ''  t ``  u _";

pub fn lookup(key: []const u8) ?Entry {
    for (entries) |entry| {
        if (std.mem.eql(u8, key, entry.key)) return entry;
    }
    return null;
}

pub fn protocolCommand(symbol: Symbol) []const u8 {
    for (entries) |entry| {
        if (entry.symbol == symbol) return entry.protocol_command;
    }
    unreachable;
}

test "regular: symbol rail maps mobile-friendly letters to coding punctuation" {
    try std.testing.expectEqual(Symbol.parens, lookup("p").?.symbol);
    try std.testing.expectEqual(Symbol.brackets, lookup("b").?.symbol);
    try std.testing.expectEqual(Symbol.braces, lookup("c").?.symbol);
    try std.testing.expectEqual(Symbol.slash, lookup("s").?.symbol);
    try std.testing.expectEqual(Symbol.line_comment, lookup("f").?.symbol);
    try std.testing.expectEqual(Symbol.star, lookup("x").?.symbol);
    try std.testing.expectEqual(Symbol.ampersand, lookup("a").?.symbol);
    try std.testing.expectEqual(Symbol.hash, lookup("h").?.symbol);
    try std.testing.expectEqual(Symbol.dollar, lookup("d").?.symbol);
    try std.testing.expectEqual(Symbol.at, lookup("r").?.symbol);
    try std.testing.expectEqual(Symbol.pipe, lookup("v").?.symbol);
    try std.testing.expectEqual(Symbol.double_quote, lookup("q").?.symbol);
    try std.testing.expectEqual(Symbol.single_quote, lookup("e").?.symbol);
    try std.testing.expectEqual(Symbol.backtick, lookup("t").?.symbol);
    try std.testing.expectEqual(Symbol.underscore, lookup("u").?.symbol);
}

test "regular: symbol rail protocol commands stay tiny and explicit" {
    try std.testing.expectEqualStrings("command pair parens", protocolCommand(.parens));
    try std.testing.expectEqualStrings("command pair brackets", protocolCommand(.brackets));
    try std.testing.expectEqualStrings("command pair braces", protocolCommand(.braces));
    try std.testing.expectEqualStrings("command insert /", protocolCommand(.slash));
    try std.testing.expectEqualStrings("command insert //", protocolCommand(.line_comment));
    try std.testing.expectEqualStrings("command insert *", protocolCommand(.star));
    try std.testing.expectEqualStrings("command insert &", protocolCommand(.ampersand));
    try std.testing.expectEqualStrings("command insert #", protocolCommand(.hash));
    try std.testing.expectEqualStrings("command insert $", protocolCommand(.dollar));
    try std.testing.expectEqualStrings("command insert @", protocolCommand(.at));
    try std.testing.expectEqualStrings("command insert |", protocolCommand(.pipe));
    try std.testing.expectEqualStrings("command pair double_quote", protocolCommand(.double_quote));
    try std.testing.expectEqualStrings("command pair single_quote", protocolCommand(.single_quote));
    try std.testing.expectEqualStrings("command pair backtick", protocolCommand(.backtick));
    try std.testing.expectEqualStrings("command insert _", protocolCommand(.underscore));
}

test "adversarial: unknown symbol key does not map to a symbol" {
    try std.testing.expectEqual(@as(?Entry, null), lookup("z"));
    try std.testing.expectEqual(@as(?Entry, null), lookup("/"));
    try std.testing.expectEqual(@as(?Entry, null), lookup(""));
}