const std = @import("std");
const Api = @import("artifacts-api");
const Allocator = std.mem.Allocator;

pub const Brain = @import("./brain.zig");
pub const TaskGraph = @import("./task_graph.zig");

const Artificer = @This();

const expiration_margin: u64 = 100 * std.time.ns_per_ms; // 100ms
const server_down_retry_interval = 5; // minutes

server: Api.Server,
characters: std.ArrayList(Brain),
task_graph: TaskGraph,

paused_until: ?i64 = null,

pub fn init(allocator: Allocator, token: []const u8) !Artificer {
    var server = try Api.Server.init(allocator);
    errdefer server.deinit();

    try server.setToken(token);

    var characters = std.ArrayList(Brain).init(allocator);
    errdefer characters.deinit(); // TODO: Add character deinit

    const chars = try server.listMyCharacters();
    defer chars.deinit();

    for (chars.items) |char| {
        try characters.append(try Brain.init(allocator, char.name));
    }

    return Artificer{
        .server = server,
        .characters = characters,
        .task_graph = TaskGraph.init(allocator)
    };
}

pub fn deinit(self: *Artificer) void {
    for (self.characters.items) |brain| {
        brain.deinit();
    }
    self.characters.deinit();
    self.server.deinit();
}

pub fn step(self: *Artificer) !void {
    if (self.paused_until) |paused_until| {
        if (std.time.timestamp() < paused_until) {
            return;
        }
        self.paused_until = null;
    }

    runNextActions(self.characters.items, &self.server) catch |err| switch (err) {
        Api.FetchError.ServerUnavailable => {
            self.paused_until = std.time.timestamp() + std.time.ns_per_min * server_down_retry_interval;
            std.log.warn("Server is down, retrying in {}min", .{ server_down_retry_interval });
            return;
        },
        else => return err
    };

    for (self.characters.items) |*brain| {
        if (brain.task == null) {
            const character = self.server.store.getCharacter(brain.name).?;
            if (character.task == null) {
                brain.task = .{ .accept_task = .{} };
            }
        }

        try brain.step(&self.server);
    }
}

pub fn nextStepAt(self: *Artificer) i64 {
    if (self.paused_until) |paused_until| {
        return paused_until;
    }

    return earliestCooldown(self.characters.items, &self.server) orelse 0;
}

fn earliestCooldown(characters: []Brain, api: *Api.Server) ?i64 {
    var earliest_cooldown: ?i64 = null;
    for (characters) |*brain| {
        if (brain.action_queue.items.len == 0) continue;

        const cooldown = brain.cooldown(api);
        if (earliest_cooldown == null or earliest_cooldown.? > cooldown) {
            earliest_cooldown = cooldown;
        }
    }

    return earliest_cooldown;
}

fn runNextActions(characters: []Brain, api: *Api.Server) !void {
    const maybe_earliest_cooldown = earliestCooldown(characters, api);
    if (maybe_earliest_cooldown == null) return;

    const earliest_cooldown = maybe_earliest_cooldown.?;
    if (earliest_cooldown < std.time.timestamp()) return;

    for (characters) |*brain| {
        if (brain.action_queue.items.len == 0) continue;

        const cooldown = brain.cooldown(api);
        if (earliest_cooldown > cooldown) {
            try brain.performNextAction(api);
        }
    }
}