from django.db import models
import secrets

from tracker import constants as C


def short_public_id() -> str:
    return "site_" + secrets.token_urlsafe(12)[:16]


class Site(models.Model):
    name = models.CharField(max_length=100)
    site_id = models.CharField(max_length=32, unique=True, default=short_public_id)
    domains = models.JSONField(default=list)          # 域名白名单 ["www.example.com"]
    allow_no_origin = models.BooleanField(default=False)  # 本地/demo 调试用
    is_active = models.BooleanField(default=True)
    timezone = models.CharField(max_length=64, default="Asia/Shanghai")
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        db_table = "site"


class Visitor(models.Model):
    site = models.ForeignKey(Site, on_delete=models.CASCADE, related_name="visitors")
    visitor_id = models.CharField(max_length=64)
    first_seen_at = models.DateTimeField(auto_now_add=True)
    last_seen_at = models.DateTimeField(auto_now_add=True)
    first_referrer_domain = models.CharField(max_length=200, blank=True, default="")
    first_utm = models.JSONField(default=dict, blank=True)
    first_landing_path = models.CharField(max_length=500, blank=True, default="")
    device_type = models.CharField(max_length=16, blank=True, default="")
    os = models.CharField(max_length=64, blank=True, default="")
    browser = models.CharField(max_length=64, blank=True, default="")
    language = models.CharField(max_length=32, blank=True, default="")
    timezone_name = models.CharField(max_length=64, blank=True, default="")
    screen = models.CharField(max_length=32, blank=True, default="")
    device_model = models.CharField(max_length=64, blank=True, default="")  # UA-CH model（如 Pixel 7；晚到 hints 允许补填一次）
    env_extra = models.JSONField(default=dict, blank=True)   # 扩展环境快照（constants.EXTENDED_ENV_KEYS 白名单，首触快照）
    last_ip = models.GenericIPAddressField(null=True, blank=True)
    country = models.CharField(max_length=64, blank=True, default="")
    province = models.CharField(max_length=64, blank=True, default="")
    city = models.CharField(max_length=64, blank=True, default="")
    visit_count = models.PositiveIntegerField(default=0)   # 会话数（服务端按新会话递增）
    active_days = models.PositiveIntegerField(default=0)   # 活跃天数
    last_active_date = models.DateField(null=True, blank=True)
    is_bot = models.BooleanField(default=False)      # UA 爬虫标记，报表默认排除

    class Meta:
        db_table = "visitor"
        constraints = [models.UniqueConstraint(fields=["site", "visitor_id"], name="uq_site_visitor")]
        indexes = [
            models.Index(fields=["site", "-last_seen_at"]),
            models.Index(fields=["site", "country"]),
        ]


class VisitSession(models.Model):
    # db_index=False：单列 FK 索引冗余——site 由 (site, started_at)、visitor 由 (visitor, -started_at) 复合索引前缀覆盖
    site = models.ForeignKey(Site, on_delete=models.CASCADE, related_name="sessions", db_index=False)
    visitor = models.ForeignKey(Visitor, on_delete=models.CASCADE, related_name="sessions", db_index=False)
    session_id = models.CharField(max_length=64)
    started_at = models.DateTimeField()
    ended_at = models.DateTimeField()
    referrer_domain = models.CharField(max_length=200, blank=True, default="")
    utm = models.JSONField(default=dict, blank=True)
    landing_path = models.CharField(max_length=500, blank=True, default="")
    event_count = models.PositiveIntegerField(default=0)
    duration_ms = models.PositiveBigIntegerField(default=0)   # 会话内事件时间跨度
    stay_ms = models.PositiveBigIntegerField(default=0)       # 有效停留累计（page_stay active_ms 之和）

    class Meta:
        db_table = "visit_session"
        constraints = [models.UniqueConstraint(fields=["site", "session_id"], name="uq_site_session")]
        indexes = [
            models.Index(fields=["visitor", "-started_at"]),
            models.Index(fields=["site", "started_at"]),   # 按日聚合/时间线查询
        ]


class Event(models.Model):
    # site/session 的单列 FK 索引冗余：site 由 (site, visitor/-occurred_at)、(site, event_name, -occurred_at)、
    # (site, occurred_at) 前缀覆盖，session 由 (session, occurred_at) 前缀覆盖，故 db_index=False。
    # visitor 保留默认索引：无其他以 visitor 打头的索引，级联删除（visitor 反向删 events）需要它。
    site = models.ForeignKey(Site, on_delete=models.CASCADE, related_name="events", db_index=False)
    visitor = models.ForeignKey(Visitor, on_delete=models.CASCADE, related_name="events")
    session = models.ForeignKey(VisitSession, on_delete=models.CASCADE, related_name="events", null=True, db_index=False)
    event_id = models.CharField(max_length=64)
    event_name = models.CharField(max_length=50)
    occurred_at = models.DateTimeField()
    received_at = models.DateTimeField(auto_now_add=True)
    path = models.CharField(max_length=500, blank=True, default="")
    title = models.CharField(max_length=200, blank=True, default="")
    properties = models.JSONField(default=dict, blank=True)
    ip = models.GenericIPAddressField(null=True, blank=True)
    country = models.CharField(max_length=64, blank=True, default="")
    province = models.CharField(max_length=64, blank=True, default="")
    city = models.CharField(max_length=64, blank=True, default="")
    late = models.BooleanField(default=False)
    is_bot = models.BooleanField(default=False)

    class Meta:
        db_table = "event"
        constraints = [models.UniqueConstraint(fields=["site", "event_id"], name="uq_site_event")]
        indexes = [
            models.Index(fields=["site", "visitor", "-occurred_at"]),
            models.Index(fields=["session", "occurred_at"]),
            models.Index(fields=["site", "event_name", "-occurred_at"]),
            models.Index(fields=["site", "occurred_at"]),   # refresh_daily 按日聚合扫描
        ]


class RawBatch(models.Model):
    """原始上报批次存档：每次 collect/batch 接收都落一行（含被拒批次）。

    用途：排查"事件为何没进报表"——原始 JSON 与入库结果（event_count/rejected_count/status）
    并排可对照白名单/超批/幂等拒绝原因。body 是脱敏后快照（敏感键值 → [FILTERED]，结构保留）；
    被拒批次截断 4KB。保留期 30 天由 cleanup_raw 命令管理（生产 cron 每日执行）。
    写入是 best-effort：失败不影响主采集流程（见 collect.py）。
    """
    site = models.ForeignKey(Site, on_delete=models.CASCADE, related_name="raw_batches")
    visitor = models.ForeignKey(Visitor, on_delete=models.CASCADE, related_name="raw_batches", null=True)
    batch_id = models.CharField(max_length=64, blank=True, default="")
    body = models.TextField()               # 脱敏后的整包 JSON 文本
    event_count = models.PositiveIntegerField(default=0)
    rejected_count = models.PositiveIntegerField(default=0)
    status = models.CharField(max_length=16, default="accepted")  # accepted/partial/rejected
    received_at = models.DateTimeField(auto_now_add=True)
    ip = models.GenericIPAddressField(null=True, blank=True)

    class Meta:
        db_table = "raw_batch"
        indexes = [models.Index(fields=["visitor", "-received_at"]),
                   models.Index(fields=["site", "-received_at"])]


class SourceClassification(models.Model):
    """来源分类结果（attribution 规则引擎的派生存储）。

    每访客两行 scope：first_touch（首访来源，session=None）/ session_entry（每次新会话入口）。
    写入两路：ingest 增量（新访客/新会话时 best-effort）+ recompute_attribution 全量重算
    （幂等 upsert）。resolution 表达证据可信度：resolved/combined/conflict/label_only/unknown——
    观察到的 referrer 与 UTM 自述矛盾时并列存 detail，不武断取一边。
    rule_version 关联 constants.ATTRIBUTION_RULE_VERSION：规则升级后可识别存量行需重算。
    """
    site = models.ForeignKey(Site, on_delete=models.CASCADE, related_name="source_classifications")
    visitor = models.ForeignKey(Visitor, on_delete=models.CASCADE, related_name="source_classifications", null=True)
    session = models.ForeignKey(VisitSession, on_delete=models.CASCADE, related_name="source_classifications", null=True)
    scope = models.CharField(max_length=16)             # first_touch / session_entry
    channel = models.CharField(max_length=32, blank=True, default="")
    platform = models.CharField(max_length=64, blank=True, default="")
    variant = models.CharField(max_length=64, blank=True, default="")
    search_term = models.CharField(max_length=200, blank=True, default="")
    evidence_kind = models.CharField(max_length=32, blank=True, default="")
    resolution = models.CharField(max_length=16, blank=True, default="")
    detail = models.JSONField(default=dict, blank=True)
    rule_version = models.CharField(max_length=16, default=C.ATTRIBUTION_RULE_VERSION)
    computed_at = models.DateTimeField(auto_now=True)

    class Meta:
        db_table = "source_classification"
        indexes = [models.Index(fields=["site", "visitor", "scope"]),
                   models.Index(fields=["site", "channel"])]


class DailyStat(models.Model):
    site = models.ForeignKey(Site, on_delete=models.CASCADE, related_name="daily_stats", db_index=False)   # uq_site_date 前缀覆盖
    date = models.DateField()
    pv = models.PositiveIntegerField(default=0)
    uv = models.PositiveIntegerField(default=0)
    sessions = models.PositiveIntegerField(default=0)
    new_visitors = models.PositiveIntegerField(default=0)

    class Meta:
        db_table = "daily_stat"
        constraints = [models.UniqueConstraint(fields=["site", "date"], name="uq_site_date")]