package tests

import "core:testing"
import assets "../src/assets"
import decks "../src/decks"
import card "../src/card"
import memory "../src/memory"
import themes "../src/themes"

// Runs the game logic forward in small steps, like frames
@(private)
advance :: proc(seconds: f32) {
    dt: f32 = 1.0 / 60
    for t: f32 = 0; t < seconds; t += dt {
        memory.update(dt)
    }
}

// Finds the card index holding the other half of card i's pair
@(private)
partner_of :: proc(i: int) -> int {
    for c, j in memory.active_cards() {
        if j != i && c.pair_id == memory.cards[i].pair_id { return j }
    }
    return -1
}

// Finds a card index that does not pair with card i
@(private)
non_partner_of :: proc(i: int) -> int {
    for c, j in memory.active_cards() {
        if j != i && c.pair_id != memory.cards[i].pair_id { return j }
    }
    return -1
}

@(test)
deck_sizes :: proc(t: ^testing.T) {
    testing.expect_value(t, len(decks.entries(.HIRAGANA)), 46)
    testing.expect_value(t, len(decks.entries(.KATAKANA)), 46)
    testing.expect_value(t, len(decks.entries(.HANGUL)), 24)
    testing.expect_value(t, len(decks.entries(.THAI_CONSONANTS)), 42)
}

@(test)
decks_have_unique_symbols_and_readings :: proc(t: ^testing.T) {
    for deck in decks.Deck_Id {
        entries := decks.entries(deck)
        for a, i in entries {
            for b, j in entries {
                if i == j { continue }
                testing.expectf(t, a.symbol != b.symbol, "%v: duplicate symbol %s", deck, a.symbol)
                // Readings may repeat (e.g. Thai "kh") only when the hint tells them apart
                same_reading := a.reading == b.reading && a.hint == b.hint
                testing.expectf(t, !same_reading, "%v: %s and %s read the same", deck, a.symbol, b.symbol)
            }
        }
    }
}

@(private)
covers :: proc(codepoints: []rune, text: cstring) -> (missing: rune, ok: bool) {
    outer: for r in string(text) {
        for c in codepoints {
            if c == r { continue outer }
        }
        return r, false
    }
    return 0, true
}

// raylib renders "?" for any glyph that wasn't baked into the font
@(test)
fonts_cover_every_deck_character :: proc(t: ^testing.T) {
    for deck in decks.Deck_Id {
        symbol_points := assets.codepoints_for(decks.language_of(deck).symbol_style)
        defer delete(symbol_points)
        ui_points := assets.codepoints_for(.BOLD)
        defer delete(ui_points)
        for entry in decks.entries(deck) {
            if r, ok := covers(symbol_points[:], entry.symbol); !ok {
                testing.expectf(t, false, "%v: %s needs %r in the symbol font", deck, entry.symbol, r)
            }
            if r, ok := covers(ui_points[:], entry.reading); !ok {
                testing.expectf(t, false, "%v: %s needs %r in the UI font", deck, entry.reading, r)
            }
            if entry.hint == nil { continue }
            if r, ok := covers(ui_points[:], entry.hint); !ok {
                testing.expectf(t, false, "%v: %s needs %r in the UI font", deck, entry.hint, r)
            }
        }
        info := decks.DECKS[deck]
        if r, ok := covers(symbol_points[:], info.native); !ok {
            testing.expectf(t, false, "%v: deck name %s needs %r", deck, info.native, r)
        }
    }
    for language in decks.Language {
        info := decks.LANGUAGES[language]
        points := assets.codepoints_for(info.congrats_style)
        defer delete(points)
        if r, ok := covers(points[:], info.congrats); !ok {
            testing.expectf(t, false, "%v: %s needs %r", language, info.congrats, r)
        }
        native_points := assets.codepoints_for(info.symbol_style)
        defer delete(native_points)
        if r, ok := covers(native_points[:], info.native); !ok {
            testing.expectf(t, false, "%v: %s needs %r", language, info.native, r)
        }
    }
}

@(test)
deal_creates_symbol_reading_pairs :: proc(t: ^testing.T) {
    for deck in decks.Deck_Id {
        for difficulty in memory.Difficulty {
            memory.deal(deck, difficulty)
            layout := memory.LAYOUTS[difficulty]
            testing.expect_value(t, memory.card_count, layout.rows * layout.cols)
            testing.expect_value(t, memory.pair_count, memory.card_count / 2)
            testing.expect_value(t, memory.state, memory.State.WAITING)
            testing.expect_value(t, memory.moves, 0)
            testing.expect_value(t, memory.matches, 0)

            for pair in 0 ..< memory.pair_count {
                symbol_count, reading_count := 0, 0
                symbol, reading, hint: cstring
                for c in memory.active_cards() {
                    if c.pair_id != pair { continue }
                    testing.expect(t, !c.face_up && !c.matched)
                    if c.is_symbol {
                        symbol_count += 1
                        symbol = c.text
                    } else {
                        reading_count += 1
                        reading = c.text
                        hint = c.hint
                    }
                }
                testing.expect_value(t, symbol_count, 1)
                testing.expect_value(t, reading_count, 1)

                // The two halves must belong to the same deck entry
                found := false
                for entry in decks.entries(deck) {
                    if entry.symbol == symbol && entry.reading == reading && entry.hint == hint { found = true }
                }
                testing.expectf(t, found, "%v pair %d is %s/%s, which is not in the deck", deck, pair, symbol, reading)
            }
        }
    }
}

@(test)
deal_lays_out_cards_on_screen_without_overlap :: proc(t: ^testing.T) {
    for difficulty in memory.Difficulty {
        memory.deal(.HIRAGANA, difficulty)
        for a, i in memory.active_cards() {
            testing.expect(t, a.rect.x >= 0 && a.rect.x + a.rect.width <= themes.SCREEN_WIDTH)
            testing.expect(t, a.rect.y >= themes.GRID_TOP && a.rect.y + a.rect.height <= themes.SCREEN_HEIGHT)
            for b, j in memory.active_cards() {
                if i == j { continue }
                overlap := a.rect.x < b.rect.x + b.rect.width && b.rect.x < a.rect.x + a.rect.width &&
                           a.rect.y < b.rect.y + b.rect.height && b.rect.y < a.rect.y + a.rect.height
                testing.expectf(t, !overlap, "cards %d and %d overlap", i, j)
            }
        }
    }
}

@(test)
matching_pair_stays_up :: proc(t: ^testing.T) {
    memory.deal(.HIRAGANA, .NORMAL)
    a := 0
    b := partner_of(a)

    testing.expect(t, memory.select_card(a))
    testing.expect_value(t, memory.state, memory.State.FIRST)
    testing.expect(t, memory.select_card(b))
    testing.expect_value(t, memory.state, memory.State.RESOLVING)
    testing.expect_value(t, memory.moves, 1)

    advance(2)
    testing.expect_value(t, memory.state, memory.State.WAITING)
    testing.expect_value(t, memory.matches, 1)
    testing.expect(t, memory.cards[a].matched && memory.cards[b].matched)
    testing.expect(t, memory.cards[a].face_up && memory.cards[b].face_up)
}

@(test)
mismatched_pair_flips_back :: proc(t: ^testing.T) {
    memory.deal(.HIRAGANA, .NORMAL)
    a := 0
    b := non_partner_of(a)

    memory.select_card(a)
    memory.select_card(b)
    advance(3)
    testing.expect_value(t, memory.state, memory.State.WAITING)
    testing.expect_value(t, memory.matches, 0)
    testing.expect_value(t, memory.moves, 1)
    testing.expect(t, !memory.cards[a].face_up && !memory.cards[b].face_up)
    testing.expect_value(t, memory.cards[a].flip_t, 0)
}

@(test)
invalid_picks_are_rejected :: proc(t: ^testing.T) {
    memory.deal(.HIRAGANA, .NORMAL)
    a := 0
    testing.expect(t, memory.select_card(a))
    testing.expect(t, !memory.select_card(a)) // same card twice

    b := non_partner_of(a)
    memory.select_card(b)
    c := non_partner_of(b)
    for c == a { c += 1 }
    testing.expect(t, !memory.select_card(c)) // a third card while resolving
    testing.expect_value(t, memory.moves, 1)

    memory.deal(.HIRAGANA, .NORMAL)
    p := partner_of(0)
    memory.select_card(0)
    memory.select_card(p)
    advance(2)
    testing.expect(t, !memory.select_card(0)) // already matched
}

@(test)
finding_all_pairs_wins :: proc(t: ^testing.T) {
    memory.deal(.HIRAGANA, .NORMAL)
    for i in 0 ..< memory.card_count {
        if memory.cards[i].matched { continue }
        memory.select_card(i)
        memory.select_card(partner_of(i))
        advance(2)
    }
    testing.expect_value(t, memory.state, memory.State.OVER)
    testing.expect_value(t, memory.matches, memory.pair_count)
    testing.expect_value(t, memory.moves, memory.pair_count)
    for &c in memory.active_cards() { testing.expect(t, c.matched) }

    // The clock stops once the game is over
    elapsed := memory.elapsed
    advance(1)
    testing.expect_value(t, memory.elapsed, elapsed)
}

@(test)
card_flip_animation_reaches_target :: proc(t: ^testing.T) {
    c := card.Card{}
    testing.expect(t, !card.is_animating(&c))

    c.face_up = true
    testing.expect(t, card.is_animating(&c))
    card.update(&c, 0.1)
    testing.expect(t, c.flip_t > 0 && c.flip_t < 1)
    for _ in 0 ..< 60 { card.update(&c, 1.0 / 60) }
    testing.expect_value(t, c.flip_t, 1)
    testing.expect(t, !card.is_animating(&c))

    c.face_up = false
    for _ in 0 ..< 60 { card.update(&c, 1.0 / 60) }
    testing.expect_value(t, c.flip_t, 0)
}

@(test)
card_pulse_counts_down :: proc(t: ^testing.T) {
    c := card.Card{}
    card.start_pulse(&c)
    testing.expect_value(t, c.pulse_t, card.PULSE_DURATION)
    card.update(&c, 1)
    testing.expect_value(t, c.pulse_t, 0)
}

@(test)
keyboard_focus_stays_inside_grid :: proc(t: ^testing.T) {
    memory.deal(.HIRAGANA, .NORMAL) // 4 rows x 6 columns
    testing.expect_value(t, memory.focus, 0)

    memory.move_focus(-1, -1) // already top-left
    testing.expect_value(t, memory.focus, 0)
    memory.move_focus(1, 0)
    testing.expect_value(t, memory.focus, 1)
    memory.move_focus(0, 1)
    testing.expect_value(t, memory.focus, 7)
    memory.move_focus(100, 100) // clamps to bottom-right
    testing.expect_value(t, memory.focus, memory.card_count - 1)

    memory.deal(.HIRAGANA, .HARD) // dealing resets focus
    testing.expect_value(t, memory.focus, 0)
    memory.move_focus(0, 3)
    testing.expect_value(t, memory.focus, 24) // 4 rows x 8 columns
}