import uuid

from django.conf import settings
from django.db import models


class Question(models.Model):
    class Track(models.TextChoices):
        BEGINNER = "beginner", "入门"
        STANDARD = "standard", "标准"
        ADVANCED = "advanced", "进阶"
        OPEN = "open", "Open"

    slug = models.SlugField(unique=True)
    track = models.CharField(max_length=16, choices=Track.choices)
    tags = models.JSONField(default=list, blank=True)
    is_active = models.BooleanField(default=True)

    def __str__(self):
        return self.slug


class QuestionVersion(models.Model):
    question = models.ForeignKey(Question, on_delete=models.CASCADE, related_name="versions")
    version = models.PositiveIntegerField()
    prompt = models.TextField()
    answer = models.CharField(max_length=200)
    explanation = models.TextField(blank=True)
    metadata = models.JSONField(default=dict, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        constraints = [
            models.UniqueConstraint(fields=("question", "version"), name="unique_question_version")
        ]

    def __str__(self):
        return f"{self.question.slug} v{self.version}"


class Contest(models.Model):
    class Kind(models.TextChoices):
        REALTIME = "realtime", "实时 1v1"
        DAILY = "daily", "今日挑战"
        PRACTICE = "practice", "单人闯关"
        WEEKLY = "weekly", "主题周赛"

    class Status(models.TextChoices):
        DRAFT = "draft", "草稿"
        PUBLISHED = "published", "已发布"
        CLOSED = "closed", "已结束"

    slug = models.SlugField(unique=True)
    title = models.CharField(max_length=120)
    kind = models.CharField(max_length=16, choices=Kind.choices)
    track = models.CharField(max_length=16, choices=Question.Track.choices)
    status = models.CharField(max_length=16, choices=Status.choices, default=Status.DRAFT)
    duration_seconds = models.PositiveIntegerField(default=60)
    starts_at = models.DateTimeField(null=True, blank=True)
    ends_at = models.DateTimeField(null=True, blank=True)

    def __str__(self):
        return self.title


class ContestQuestion(models.Model):
    contest = models.ForeignKey(Contest, on_delete=models.CASCADE, related_name="contest_questions")
    question_version = models.ForeignKey(QuestionVersion, on_delete=models.PROTECT)
    order = models.PositiveIntegerField()
    points = models.PositiveIntegerField(default=100)

    class Meta:
        constraints = [
            models.UniqueConstraint(fields=("contest", "order"), name="unique_contest_question_order")
        ]
        ordering = ["order"]


class RealtimeMatch(models.Model):
    class Status(models.TextChoices):
        WAITING = "waiting", "等待对手"
        ACTIVE = "active", "进行中"
        COMPLETED = "completed", "已完成"
        CANCELLED = "cancelled", "已取消"

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    contest = models.ForeignKey(Contest, on_delete=models.PROTECT)
    player_one = models.ForeignKey(
        settings.AUTH_USER_MODEL, on_delete=models.PROTECT, related_name="matches_as_player_one"
    )
    player_two = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.PROTECT,
        related_name="matches_as_player_two",
    )
    status = models.CharField(max_length=16, choices=Status.choices, default=Status.WAITING)
    player_one_rating = models.PositiveIntegerField()
    player_two_rating = models.PositiveIntegerField(null=True, blank=True)
    winner = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.PROTECT,
        related_name="won_matches",
    )
    created_at = models.DateTimeField(auto_now_add=True)
    started_at = models.DateTimeField(null=True, blank=True)
    completed_at = models.DateTimeField(null=True, blank=True)

    class Meta:
        indexes = [
            models.Index(
                fields=("contest", "status", "player_one_rating", "created_at"),
                name="matchmaking_lookup_idx",
            )
        ]


class ContestAttempt(models.Model):
    class Status(models.TextChoices):
        ACTIVE = "active", "进行中"
        SUBMITTED = "submitted", "已提交"
        EXPIRED = "expired", "已超时"

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    contest = models.ForeignKey(Contest, on_delete=models.PROTECT, related_name="attempts")
    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="contest_attempts")
    match = models.ForeignKey(
        RealtimeMatch, null=True, blank=True, on_delete=models.PROTECT, related_name="attempts"
    )
    status = models.CharField(max_length=16, choices=Status.choices, default=Status.ACTIVE)
    score = models.PositiveIntegerField(default=0)
    correct_count = models.PositiveIntegerField(default=0)
    answer_count = models.PositiveIntegerField(default=0)
    duration_ms = models.PositiveIntegerField(default=0)
    submission_key = models.CharField(max_length=80, null=True, blank=True)
    started_at = models.DateTimeField(auto_now_add=True)
    submitted_at = models.DateTimeField(null=True, blank=True)

    class Meta:
        constraints = [
            models.UniqueConstraint(
                fields=("user", "submission_key"), name="unique_user_contest_submission"
            )
        ]
        ordering = ["-started_at"]


class ContestAnswer(models.Model):
    attempt = models.ForeignKey(ContestAttempt, on_delete=models.CASCADE, related_name="answers")
    contest_question = models.ForeignKey(ContestQuestion, on_delete=models.PROTECT)
    submitted_answer = models.CharField(max_length=200)
    is_correct = models.BooleanField()
    elapsed_ms = models.PositiveIntegerField()
    answered_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        constraints = [
            models.UniqueConstraint(
                fields=("attempt", "contest_question"), name="unique_attempt_question_answer"
            )
        ]


class RatingHistory(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="rating_history")
    match = models.ForeignKey(RealtimeMatch, on_delete=models.PROTECT, related_name="rating_changes")
    rating_before = models.PositiveIntegerField()
    rating_after = models.PositiveIntegerField()
    delta = models.SmallIntegerField()
    created_at = models.DateTimeField(auto_now_add=True)


class LeaderboardSnapshot(models.Model):
    contest = models.ForeignKey(Contest, on_delete=models.CASCADE)
    track = models.CharField(max_length=16, choices=Question.Track.choices)
    period = models.CharField(max_length=40)
    rankings = models.JSONField(default=list)
    generated_at = models.DateTimeField(auto_now_add=True)


class CheatFlag(models.Model):
    class Status(models.TextChoices):
        OPEN = "open", "待处理"
        DISMISSED = "dismissed", "已忽略"
        CONFIRMED = "confirmed", "已确认"

    attempt = models.ForeignKey(ContestAttempt, on_delete=models.CASCADE, related_name="cheat_flags")
    reason = models.CharField(max_length=120)
    evidence = models.JSONField(default=dict)
    status = models.CharField(max_length=16, choices=Status.choices, default=Status.OPEN)
    created_at = models.DateTimeField(auto_now_add=True)


class MathGameAttempt(models.Model):
    class Kind(models.TextChoices):
        SUDOKU = "sudoku", "数独"
        TWENTY_FOUR = "twenty_four", "24 点"

    class Difficulty(models.TextChoices):
        EASY = "easy", "入门"
        STANDARD = "standard", "标准"
        HARD = "hard", "进阶"

    class Status(models.TextChoices):
        ACTIVE = "active", "进行中"
        COMPLETED = "completed", "已完成"
        FAILED = "failed", "未通过"

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name="math_game_attempts",
    )
    kind = models.CharField(max_length=20, choices=Kind.choices)
    difficulty = models.CharField(
        max_length=16,
        choices=Difficulty.choices,
        default=Difficulty.STANDARD,
    )
    puzzle = models.JSONField(default=dict)
    solution = models.JSONField(default=dict)
    submission = models.JSONField(default=dict, blank=True)
    status = models.CharField(max_length=16, choices=Status.choices, default=Status.ACTIVE)
    score = models.PositiveIntegerField(default=0)
    duration_ms = models.PositiveIntegerField(default=0)
    hints_used = models.PositiveSmallIntegerField(default=0)
    submission_key = models.CharField(max_length=80, null=True, blank=True)
    started_at = models.DateTimeField(auto_now_add=True)
    submitted_at = models.DateTimeField(null=True, blank=True)

    class Meta:
        constraints = [
            models.UniqueConstraint(
                fields=("user", "submission_key"),
                name="unique_user_math_game_submission",
            )
        ]
        indexes = [
            models.Index(
                fields=("kind", "status", "-score", "duration_ms"),
                name="math_game_ranking_idx",
            )
        ]
        ordering = ["-started_at"]