// Reimplementations of the following tests from Flecs:
// https://github.com/SanderMertens/flecs/blob/master/test/api/src/World.c

const std = @import("std");
const alloc = std.testing.allocator;
const expect = @import("../src/expect.zig");

const util = @import("./util.zig");
const flecs = @import("../src/main.zig");
const c = flecs.c;

const context = flecs.Context(void);
const World = context.World;
const Iter = context.Iter;
const Entity = context.Entity;

const Position = struct { x: f32, y: f32 };
const Velocity = struct { x: f32, y: f32 };

fn move(it: Iter) void {
    var pos = it.field(Position, 1);
    var vel = it.field(Velocity, 2);
    util.Probe.probeIter(it) catch unreachable;

    for (pos, vel) |*p, *v| {
        p.x += v.x * it.getDeltaTime();
        p.y += v.y * it.getDeltaTime();
    }
}

fn lookup(comptime T: type) c.ecs_entity_t {
    return flecs.Lookup(void, T).id;
}

test "World_progress_w_0" {
    flecs.init(std.testing.allocator);
    var world = try World.init();
    defer world.deinit();

    _ = try world.component(Position);
    _ = try world.component(Velocity);

    const e1 = try world.entity(.{}, .{ Position, Velocity });

    const move_system = try world.system("move", move, c.EcsOnUpdate, "Position, Velocity");

    var ctx = util.Probe.init();
    c.ecs_set_context(world.raw, &ctx);

    e1.set(Position, .{ .x = 0, .y = 0 });
    e1.set(Velocity, .{ .x = 1, .y = 2 });

    _ = world.progress(0);

    try expect.equal(1, ctx.count);
    try expect.equal(1, ctx.invoked);
    try expect.equal(move_system.raw, ctx.system);
    try expect.equal(2, ctx.termCount);
    try expect.equal(null, ctx.param);

    try expect.equal(e1.raw, ctx.e[0]);
    try expect.equal(lookup(Position), ctx.c[0][0]);
    try expect.equal(lookup(Velocity), ctx.c[0][1]);
    try expect.equal(0, ctx.s[0][0]);
    try expect.equal(0, ctx.s[0][1]);

    const p = e1.get(Position).?;
    try expect.true(p.x != 0);
    try expect.true(p.y != 0);
}

test "World_progress_w_t" {
    flecs.init(std.testing.allocator);
    var world = try World.init();
    defer world.deinit();

    _ = try world.component(Position);
    _ = try world.component(Velocity);

    const e1 = try world.entity(.{}, .{ Position, Velocity });

    const move_system = try world.system("move", move, c.EcsOnUpdate, "Position, Velocity");

    var ctx = util.Probe.init();
    c.ecs_set_context(world.raw, &ctx);

    e1.set(Position, .{ .x = 0, .y = 0 });
    e1.set(Velocity, .{ .x = 1, .y = 2 });

    _ = world.progress(2);

    try expect.equal(1, ctx.count);
    try expect.equal(1, ctx.invoked);
    try expect.equal(move_system.raw, ctx.system);
    try expect.equal(2, ctx.termCount);
    try expect.equal(null, ctx.param);

    try expect.equal(e1.raw, ctx.e[0]);
    try expect.equal(lookup(Position), ctx.c[0][0]);
    try expect.equal(lookup(Velocity), ctx.c[0][1]);
    try expect.equal(0, ctx.s[0][0]);
    try expect.equal(0, ctx.s[0][1]);

    const p = e1.get(Position).?;
    try expect.equal(2, p.x);
    try expect.equal(4, p.y);
}