from datetime import datetime, timezone

from pgvector.sqlalchemy import Vector
from sqlalchemy import JSON, Boolean, Column, DateTime, Float, ForeignKey, Integer, LargeBinary, String, Text, UniqueConstraint
from sqlalchemy.types import TypeDecorator

from .db import Base


def now():
    return datetime.now(timezone.utc)


class Embedding(TypeDecorator):
    impl = JSON
    cache_ok = True

    def load_dialect_impl(self, dialect):
        return dialect.type_descriptor(Vector(1024) if dialect.name == "postgresql" else JSON())


class Course(Base):
    __tablename__ = "courses"
    id = Column(Integer, primary_key=True)
    name = Column(String(200), unique=True, nullable=False)
    code = Column(String(100), unique=True, nullable=False)
    created_at = Column(DateTime(timezone=True), default=now)


class CourseVersion(Base):
    __tablename__ = "course_versions"
    id = Column(Integer, primary_key=True)
    course_id = Column(Integer, ForeignKey("courses.id"), nullable=False)
    version = Column(Integer, nullable=False)
    title = Column(String(200), nullable=False)
    objectives = Column(JSON, default=list, nullable=False)
    indicators = Column(JSON, default=list, nullable=False)
    directions = Column(JSON, default=list, nullable=False)
    prompts = Column(JSON, default=dict, nullable=False)
    templates = Column(JSON, default=list, nullable=False)
    published = Column(Boolean, default=False, nullable=False)
    created_at = Column(DateTime(timezone=True), default=now)
    __table_args__ = (UniqueConstraint("course_id", "version"),)


class CourseObjective(Base):
    __tablename__ = "course_objectives"
    id = Column(Integer, primary_key=True)
    course_version_id = Column(Integer, ForeignKey("course_versions.id"), nullable=False)
    code = Column(String(50), nullable=False)
    name = Column(String(300), nullable=False)
    description = Column(Text, default="")
    indicator_codes = Column(JSON, default=list)
    __table_args__ = (UniqueConstraint("course_version_id", "code"),)


class GraduationIndicator(Base):
    __tablename__ = "graduation_indicators"
    id = Column(Integer, primary_key=True)
    course_version_id = Column(Integer, ForeignKey("course_versions.id"), nullable=False)
    code = Column(String(50), nullable=False)
    description = Column(Text, nullable=False)
    __table_args__ = (UniqueConstraint("course_version_id", "code"),)


class TopicDirection(Base):
    __tablename__ = "topic_directions"
    id = Column(Integer, primary_key=True)
    course_version_id = Column(Integer, ForeignKey("course_versions.id"), nullable=False)
    name = Column(String(200), nullable=False)
    examples = Column(JSON, default=list)
    __table_args__ = (UniqueConstraint("course_version_id", "name"),)


class RubricVersion(Base):
    __tablename__ = "rubric_versions"
    id = Column(Integer, primary_key=True)
    course_version_id = Column(Integer, ForeignKey("course_versions.id"), nullable=False)
    version = Column(Integer, nullable=False)
    criteria = Column(JSON, default=list, nullable=False)
    weights = Column(JSON, default=dict, nullable=False)
    published = Column(Boolean, default=False, nullable=False)
    created_at = Column(DateTime(timezone=True), default=now)
    __table_args__ = (UniqueConstraint("course_version_id", "version"),)


class RubricCriterion(Base):
    __tablename__ = "rubric_criteria"
    id = Column(Integer, primary_key=True)
    rubric_version_id = Column(Integer, ForeignKey("rubric_versions.id"), nullable=False)
    criterion_id = Column(String(100), nullable=False)
    category = Column(String(50), nullable=False)
    name = Column(String(300), nullable=False)
    description = Column(Text, nullable=False)
    max_score = Column(Float, nullable=False)
    linked_objectives = Column(JSON, default=list)
    linked_outcomes = Column(JSON, default=list)
    required_evidence = Column(JSON, default=list)
    __table_args__ = (UniqueConstraint("rubric_version_id", "criterion_id"),)


class RubricScoreLevel(Base):
    __tablename__ = "rubric_score_levels"
    id = Column(Integer, primary_key=True)
    rubric_criterion_id = Column(Integer, ForeignKey("rubric_criteria.id"), nullable=False)
    min_score = Column(Float, nullable=False)
    max_score = Column(Float, nullable=False)
    description = Column(Text, nullable=False)


class Student(Base):
    __tablename__ = "students"
    id = Column(Integer, primary_key=True)
    student_no = Column(String(80), unique=True, nullable=False)
    name = Column(String(100), nullable=False)


class Project(Base):
    __tablename__ = "projects"
    id = Column(Integer, primary_key=True)
    course_version_id = Column(Integer, ForeignKey("course_versions.id"), nullable=False)
    student_id = Column(Integer, ForeignKey("students.id"), nullable=False)
    topic = Column(String(500), nullable=False)
    direction = Column(String(200), default="")
    source_dir = Column(String(1000), nullable=False)
    status = Column(String(40), default="imported")
    facts = Column(JSON, default=dict, nullable=False)
    created_at = Column(DateTime(timezone=True), default=now)
    __table_args__ = (UniqueConstraint("course_version_id", "source_dir"),)


class Submission(Base):
    __tablename__ = "submissions"
    id = Column(Integer, primary_key=True)
    project_id = Column(Integer, ForeignKey("projects.id"), nullable=False)
    category = Column(String(50), nullable=False)
    status = Column(String(40), nullable=False)
    __table_args__ = (UniqueConstraint("project_id", "category"),)


class SubmissionFile(Base):
    __tablename__ = "submission_files"
    id = Column(Integer, primary_key=True)
    project_id = Column(Integer, ForeignKey("projects.id"), nullable=False)
    submission_id = Column(Integer, ForeignKey("submissions.id"), nullable=True)
    category = Column(String(40), nullable=False)
    relative_path = Column(String(1200), nullable=False)
    mime_type = Column(String(100), nullable=False)
    size = Column(Integer, nullable=False)
    mtime = Column(Float, nullable=False)
    sha256 = Column(String(64), nullable=False)
    recognition_status = Column(String(40), nullable=False)
    parse_status = Column(String(40), default="pending")
    parse_error = Column(Text, default="")
    parsed = Column(JSON, default=dict, nullable=False)
    __table_args__ = (UniqueConstraint("project_id", "relative_path"),)


class KnowledgeDocument(Base):
    __tablename__ = "knowledge_documents"
    id = Column(Integer, primary_key=True)
    course_version_id = Column(Integer, ForeignKey("course_versions.id"), nullable=False)
    project_id = Column(Integer, ForeignKey("projects.id"), nullable=True)
    submission_file_id = Column(Integer, ForeignKey("submission_files.id"), nullable=True)
    title = Column(String(500), nullable=False)
    document_type = Column(String(80), nullable=False)
    source_hash = Column(String(64), nullable=False)
    index_version = Column(Integer, nullable=False, default=5, server_default="5")
    revision = Column(Integer, nullable=False, default=1, server_default="1")
    status = Column(String(40), default="ready")
    __table_args__ = (UniqueConstraint("course_version_id", "project_id", "submission_file_id", "source_hash", "revision",
                                     name="uq_knowledge_document_revision"),)


class KnowledgePage(Base):
    __tablename__ = "knowledge_pages"
    document_id = Column(Integer, ForeignKey("knowledge_documents.id", ondelete="CASCADE"), primary_key=True)
    page = Column(Integer, primary_key=True)
    text = Column(Text, nullable=False, default="")
    image_path = Column(String(1200), nullable=True)  # Relative to processed_path.
    # Page-level classification: cover, abstract, toc, body, references or unknown.
    page_type = Column(String(20), nullable=False, default="unknown", server_default="unknown")
    mixed = Column(Boolean, nullable=False, default=False, server_default="false")
    section = Column(String(500), default="")
    chapter = Column(String(500), default="")
    confidence = Column(Float, nullable=True)
    # Bounded classifier evidence: which signals decided the type, kept for audit.
    classification = Column(JSON, default=dict, nullable=False)


class KnowledgeChunk(Base):
    __tablename__ = "knowledge_chunks"
    id = Column(Integer, primary_key=True)
    document_id = Column(Integer, ForeignKey("knowledge_documents.id"), nullable=False)
    course_version_id = Column(Integer, nullable=False)
    project_id = Column(Integer, nullable=True)
    document_type = Column(String(80), nullable=False)
    page = Column(Integer, nullable=False)
    section = Column(String(500), default="")
    chapter = Column(String(500), default="")
    page_type = Column(String(20), nullable=False, default="unknown", server_default="unknown")
    block_type = Column(String(20), nullable=False, default="body", server_default="body")
    text = Column(Text, nullable=False)
    embedding = Column(Embedding, nullable=True)


class ScoringBatch(Base):
    __tablename__ = "scoring_batches"
    id = Column(Integer, primary_key=True)
    course_version_id = Column(Integer, ForeignKey("course_versions.id"), nullable=False)
    rubric_version_id = Column(Integer, ForeignKey("rubric_versions.id"), nullable=False)
    course_snapshot = Column(JSON, nullable=False)
    rubric_snapshot = Column(JSON, nullable=False)
    model_config_snapshot = Column(JSON, nullable=False)
    embedding_model_name = Column(String(200), nullable=False)
    embedding_model_version = Column(String(100), nullable=False)
    status = Column(String(40), default="created")
    project_ids = Column(JSON, nullable=True)  # NULL identifies a legacy batch with unknown original membership.
    progress_done = Column(Integer, default=0)
    progress_total = Column(Integer, default=0)
    error = Column(Text, default="")
    created_at = Column(DateTime(timezone=True), default=now)
    finished_at = Column(DateTime(timezone=True), nullable=True)


class CriterionScore(Base):
    __tablename__ = "criterion_scores"
    id = Column(Integer, primary_key=True)
    batch_id = Column(Integer, ForeignKey("scoring_batches.id"), nullable=False)
    project_id = Column(Integer, ForeignKey("projects.id"), nullable=False)
    criterion_id = Column(String(100), nullable=False)
    model_score = Column(Float, nullable=True)
    teacher_score = Column(Float, nullable=True)
    model_comment = Column(Text, default="")
    teacher_comment = Column(Text, nullable=True)
    confidence = Column(Float, nullable=True)
    missing_evidence = Column(JSON, default=list)
    suggestion = Column(Text, default="")
    status = Column(String(40), default="pending")
    error = Column(Text, default="")
    #: Content targets that still lacked body evidence, with the search that was run.
    #: Kept after teacher review so the original retrieval problem stays auditable.
    evidence_gaps = Column(JSON, default=list)
    __table_args__ = (UniqueConstraint("batch_id", "project_id", "criterion_id"),)

    @property
    def final_score(self):
        return self.teacher_score if self.teacher_score is not None else self.model_score


class ScoreEvidence(Base):
    __tablename__ = "score_evidences"
    id = Column(Integer, primary_key=True)
    score_id = Column(Integer, ForeignKey("criterion_scores.id"), nullable=False)
    document_id = Column(Integer, ForeignKey("knowledge_documents.id"), nullable=True)
    submission_file_id = Column(Integer, ForeignKey("submission_files.id"), nullable=True)
    page = Column(Integer, nullable=False)
    quote = Column(Text, nullable=False)
    image_path = Column(String(1200), nullable=True)
    # Which required-evidence target this quotation is offered to support.
    target_id = Column(String(50), default="", server_default="")
    target_label = Column(String(300), default="", server_default="")
    # Page type of the source passage, and its role in the judgement.
    page_type = Column(String(20), default="unknown", server_default="unknown")
    source_role = Column(String(20), default="content", server_default="content")
    # True when the quotation was written before this retrieval policy existed.
    historical = Column(Boolean, default=False, nullable=False, server_default="false")


class TeacherRevision(Base):
    __tablename__ = "teacher_revisions"
    id = Column(Integer, primary_key=True)
    score_id = Column(Integer, ForeignKey("criterion_scores.id"), nullable=False)
    old_score = Column(Float, nullable=True)
    new_score = Column(Float, nullable=True)
    old_comment = Column(Text, nullable=True)
    new_comment = Column(Text, nullable=True)
    reason = Column(Text, default="")
    created_at = Column(DateTime(timezone=True), default=now)


class ExportTask(Base):
    __tablename__ = "export_tasks"
    id = Column(Integer, primary_key=True)
    batch_id = Column(Integer, ForeignKey("scoring_batches.id"), nullable=False)
    project_id = Column(Integer, ForeignKey("projects.id"), nullable=True)
    kind = Column(String(20), nullable=False)
    path = Column(String(1200), nullable=True)
    status = Column(String(40), default="queued")
    error = Column(Text, default="")
    created_at = Column(DateTime(timezone=True), default=now)


class AppSetting(Base):
    __tablename__ = "app_settings"
    key = Column(String(100), primary_key=True)
    encrypted_value = Column(LargeBinary, nullable=False)
    updated_at = Column(DateTime(timezone=True), default=now)


class AuditLog(Base):
    __tablename__ = "audit_logs"
    id = Column(Integer, primary_key=True)
    action = Column(String(100), nullable=False)
    entity_type = Column(String(100), nullable=False)
    entity_id = Column(Integer, nullable=True)
    details = Column(JSON, default=dict)
    created_at = Column(DateTime(timezone=True), default=now)


class IndexTask(Base):
    __tablename__ = "index_tasks"
    id = Column(Integer, primary_key=True)
    course_version_id = Column(Integer, ForeignKey("course_versions.id"), nullable=False)
    submission_file_id = Column(Integer, ForeignKey("submission_files.id"), nullable=True)
    kind = Column(String(30), nullable=False)
    status = Column(String(30), nullable=False, default="queued")
    result = Column(JSON, nullable=False, default=dict)
    error = Column(Text, default="")
    created_at = Column(DateTime(timezone=True), default=now)
    updated_at = Column(DateTime(timezone=True), default=now, onupdate=now)


class Conversation(Base):
    __tablename__ = "conversations"
    id = Column(Integer, primary_key=True)
    title = Column(String(200), nullable=False, default="新会话")
    first_request_id = Column(String(36), nullable=True, unique=True)
    course_version_id = Column(Integer, ForeignKey("course_versions.id"), nullable=True)
    batch_id = Column(Integer, ForeignKey("scoring_batches.id"), nullable=True)
    project_id = Column(Integer, ForeignKey("projects.id"), nullable=True)
    created_at = Column(DateTime(timezone=True), default=now)
    updated_at = Column(DateTime(timezone=True), default=now, onupdate=now)


class ChatMessage(Base):
    __tablename__ = "chat_messages"
    id = Column(Integer, primary_key=True)
    conversation_id = Column(Integer, ForeignKey("conversations.id"), nullable=False)
    role = Column(String(20), nullable=False)
    content = Column(Text, nullable=False, default="")
    citations = Column(JSON, nullable=False, default=list)
    tool_calls = Column(JSON, nullable=False, default=list)
    created_at = Column(DateTime(timezone=True), default=now)


class AgentRun(Base):
    __tablename__ = "agent_runs"
    id = Column(Integer, primary_key=True)
    conversation_id = Column(Integer, ForeignKey("conversations.id"), nullable=False)
    status = Column(String(30), nullable=False, default="running")
    error = Column(Text, default="")
    tool_calls = Column(JSON, nullable=False, default=list)
    events = Column(JSON, nullable=False, default=list)
    created_at = Column(DateTime(timezone=True), default=now)
    finished_at = Column(DateTime(timezone=True), nullable=True)


class PendingAction(Base):
    __tablename__ = "pending_actions"
    id = Column(Integer, primary_key=True)
    conversation_id = Column(Integer, ForeignKey("conversations.id"), nullable=False)
    kind = Column(String(40), nullable=False)
    payload = Column(JSON, nullable=False)
    preview = Column(JSON, nullable=False)
    expected = Column(JSON, nullable=False)
    idempotency_key = Column(String(64), nullable=False, unique=True)
    status = Column(String(30), nullable=False, default="pending")
    result = Column(JSON, nullable=True)
    created_at = Column(DateTime(timezone=True), default=now)
    expires_at = Column(DateTime(timezone=True), nullable=False)