// TODO: Change this to proper TOML in the future :)

const es = @import("root");
const std = @import("std");

const Allocator = std.mem.Allocator;
const BufMap = std.BufMap;
const Config = @This();

const config_path = "arkta/es/es.ini";

hard_tabs: bool = es.conf.default_hard_tabs,
line_limit: usize = es.conf.default_line_limit,
page_overlap: usize = es.conf.default_page_overlap,
tab_stop: usize = es.conf.default_tab_stop,

pub fn readConfig(allocator: Allocator) !Config {
    var config = Config{};

    var env_map = try std.process.getEnvMap(allocator);
    defer env_map.deinit();

    if (env_map.get("XDG_CONFIG_DIRS")) |base_dirs| {
        var it = std.mem.split(u8, base_dirs, ":");
        while (it.next()) |base_dir| {
            try readConfigInBaseDir(allocator, &config, base_dir);
        }
    } else {
        try readConfigInBaseDir(allocator, &config, "/etc/xdg");
    }

    if (env_map.get("XDG_CONFIG_HOME")) |base_dir| {
        try readConfigInBaseDir(allocator, &config, base_dir);
    } else if (env_map.get("HOME")) |home| {
        const home_config = try std.fs.path.join(allocator, &.{ home, ".config" });
        defer allocator.free(home_config);

        try readConfigInBaseDir(allocator, &config, home_config);
    } else {
        std.log.err("No $HOME environment variable available!", .{});
    }

    return config;
}

fn parseBool(str: []const u8) !bool {
    if (std.mem.eql(u8, str, "true")) {
        return true;
    } else if (std.mem.eql(u8, str, "false")) {
        return false;
    } else {
        std.log.err("How to interpret '{s}' as a bool?", .{str});
        return error.MalformedConfig;
    }
}

fn readConfigInBaseDir(allocator: Allocator, config: *Config, base_dir: []const u8) !void {
    const filename = try std.fs.path.join(allocator, &.{ base_dir, config_path });
    defer allocator.free(filename);

    const file = std.fs.openFileAbsolute(filename, .{ .mode = .read_only }) catch |err| switch (err) {
        error.FileNotFound => return,
        else => return err,
    };
    defer file.close();

    const reader = file.reader();
    while (try reader.readUntilDelimiterOrEofAlloc(allocator, '\n', 4096)) |line_buf| {
        defer allocator.free(line_buf);

        var line = std.mem.trim(u8, line_buf, &std.ascii.whitespace);
        if (line.len == 0 or line[0] == '#') {
            continue;
        }

        const split = if (std.mem.indexOfScalar(u8, line, '=')) |idx| idx else {
            return error.MalformedConfig;
        };

        const key = std.mem.trimRight(u8, line[0..split], &std.ascii.whitespace);
        const value = std.mem.trimLeft(u8, line[(split + 1)..], &std.ascii.whitespace);
        if (std.mem.eql(u8, key, "hard-tabs")) {
            config.hard_tabs = try parseBool(value);
        } else if (std.mem.eql(u8, key, "line-limit")) {
            config.line_limit = try std.fmt.parseUnsigned(usize, value, 0);
        } else if (std.mem.eql(u8, key, "page-overlap")) {
            config.page_overlap = try std.fmt.parseUnsigned(usize, value, 0);
        } else if (std.mem.eql(u8, key, "tab-stop")) {
            config.tab_stop = try std.fmt.parseUnsigned(usize, value, 0);
        }
        // TODO: else ??
    }
}