import enum
import uuid
from datetime import datetime
from sqlalchemy import Column, String, Integer, BigInteger, Boolean, Enum as SQLEnum, Text, JSON, DateTime, ForeignKey
from sqlalchemy.orm import relationship
from app.core.database.db_session import Base

def generate_uuid():
    return str(uuid.uuid4())

class BatchTypeEnum(str, enum.Enum):
    PRODUCTS = "PRODUCTS"
    VARIANTS = "VARIANTS"
    MEDIA = "MEDIA"
    INVENTORY = "INVENTORY"
    CRM_LEADS = "CRM_LEADS"
    REPAIR_CATALOG = "REPAIR_CATALOG"
    CUSTOMERS = "CUSTOMERS"
    WAREHOUSES = "WAREHOUSES"

class ImportModeEnum(str, enum.Enum):
    CREATE_ONLY = "CREATE_ONLY"
    UPDATE_EXISTING = "UPDATE_EXISTING"
    UPSERT = "UPSERT"
    SKIP_EXISTING = "SKIP_EXISTING"

class BatchStatusEnum(str, enum.Enum):
    PENDING = "PENDING"
    VALIDATING = "VALIDATING"
    READY = "READY"
    PROCESSING = "PROCESSING"
    COMPLETED = "COMPLETED"
    FAILED = "FAILED"
    ROLLED_BACK = "ROLLED_BACK"

class JobStatusEnum(str, enum.Enum):
    QUEUED = "QUEUED"
    VALIDATING = "VALIDATING"
    RUNNING = "RUNNING"
    CANCELLING = "CANCELLING"
    CANCELLED = "CANCELLED"
    FAILED = "FAILED"
    COMPLETED = "COMPLETED"

class PhaseEnum(str, enum.Enum):
    UPLOAD = "UPLOAD"
    VALIDATE = "VALIDATE"
    DRY_RUN = "DRY_RUN"
    MASTER_DATA = "MASTER_DATA"
    PRODUCTS = "PRODUCTS"
    VARIANTS = "VARIANTS"
    MEDIA_PROCESS = "MEDIA_PROCESS"
    MEDIA_LINK = "MEDIA_LINK"
    VERIFY = "VERIFY"
    COMPLETED = "COMPLETED"

class MediaItemStatusEnum(str, enum.Enum):
    PENDING = "PENDING"
    PROCESSING = "PROCESSING"
    STORED = "STORED"
    REGISTERED = "REGISTERED"
    FAILED = "FAILED"

class RetryStatusEnum(str, enum.Enum):
    UNRESOLVED = "UNRESOLVED"
    RETRYING = "RETRYING"
    RETRIED = "RETRIED"
    RESOLVED = "RESOLVED"
    SKIPPED = "SKIPPED"
    PERMANENT_FAILURE = "PERMANENT_FAILURE"

class ErrorSeverityEnum(str, enum.Enum):
    ERROR = "ERROR"
    WARNING = "WARNING"

class MediaSourceTypeEnum(str, enum.Enum):
    MEDIA_JSON = "MEDIA_JSON"
    FOLDER_PATH = "FOLDER_PATH"

class MigrationBatch(Base):
    __tablename__ = "migration_batches"

    id = Column(String(36), primary_key=True, default=generate_uuid)
    batch_type = Column(SQLEnum(BatchTypeEnum), nullable=False, default=BatchTypeEnum.PRODUCTS)
    user_id = Column(String(36), nullable=False)
    import_mode = Column(SQLEnum(ImportModeEnum), nullable=False, default=ImportModeEnum.UPSERT)
    status = Column(SQLEnum(BatchStatusEnum), nullable=False, default=BatchStatusEnum.PENDING)
    created_at = Column(DateTime, default=datetime.utcnow)
    completed_at = Column(DateTime, nullable=True)

    jobs = relationship("MigrationJob", back_populates="batch", cascade="all, delete-orphan")
    snapshots = relationship("MigrationSnapshot", back_populates="batch", cascade="all, delete-orphan")

class MappingConfig(Base):
    __tablename__ = "mapping_configs"

    id = Column(String(36), primary_key=True, default=generate_uuid)
    name = Column(String(100), nullable=False)
    entity_type = Column(String(50), nullable=False)
    column_maps = Column(JSON, nullable=False)
    created_by = Column(String(36), nullable=False)
    created_at = Column(DateTime, default=datetime.utcnow)

class MediaGroup(Base):
    __tablename__ = "media_groups"

    id = Column(String(36), primary_key=True, default=generate_uuid)
    media_key = Column(String(255), unique=True, nullable=False, index=True)
    source_type = Column(SQLEnum(MediaSourceTypeEnum), nullable=False, default=MediaSourceTypeEnum.FOLDER_PATH)
    brand_name = Column(String(100), nullable=True)
    model_name = Column(String(100), nullable=True)
    variant_tag = Column(String(100), nullable=True)
    created_at = Column(DateTime, default=datetime.utcnow)

    media_assets = relationship("MediaAsset", back_populates="group", cascade="all, delete-orphan")

class MediaAsset(Base):
    __tablename__ = "media_library"

    id = Column(String(36), primary_key=True, default=generate_uuid)
    media_group_id = Column(String(36), ForeignKey("media_groups.id", ondelete="CASCADE"), nullable=False)
    original_filename = Column(String(255), nullable=False)
    stored_filename = Column(String(255), nullable=False)
    mime_type = Column(String(50), nullable=False)
    file_size_bytes = Column(BigInteger, nullable=False)
    width = Column(Integer, nullable=False, default=0)
    height = Column(Integer, nullable=False, default=0)
    sha256_checksum = Column(String(64), unique=True, nullable=False, index=True)  # Global unique SHA-256 asset
    cdn_url = Column(String(512), nullable=False)
    thumbnail_url = Column(String(512), nullable=False)
    storage_path = Column(String(512), nullable=True)
    exif_metadata = Column(JSON, nullable=True)
    created_at = Column(DateTime, default=datetime.utcnow)

    group = relationship("MediaGroup", back_populates="media_assets")

class MigrationJob(Base):
    __tablename__ = "migration_jobs"

    id = Column(String(36), primary_key=True, default=generate_uuid)
    batch_id = Column(String(36), ForeignKey("migration_batches.id", ondelete="CASCADE"), nullable=False)
    job_type = Column(String(50), nullable=False, default="PRODUCTS")
    is_dry_run = Column(Boolean, nullable=False, default=False)
    file_name = Column(String(255), nullable=False, default="")
    file_format = Column(String(10), nullable=False, default="CSV")

    status = Column(SQLEnum(JobStatusEnum), nullable=False, default=JobStatusEnum.QUEUED, index=True)
    current_phase = Column(SQLEnum(PhaseEnum), nullable=False, default=PhaseEnum.UPLOAD, index=True)

    # Worker Lease & Lock
    worker_id = Column(String(64), nullable=True, index=True)
    locked_at = Column(DateTime, nullable=True)
    heartbeat_at = Column(DateTime, nullable=True)
    lease_version = Column(BigInteger, nullable=False, default=1)

    # Cancellation
    cancel_requested_at = Column(DateTime, nullable=True)

    # Phase Progress
    current_batch = Column(Integer, nullable=False, default=0)
    total_batches = Column(Integer, nullable=False, default=0)
    last_successful_batch = Column(Integer, nullable=False, default=0)

    # Overall Progress
    processed_records = Column(Integer, nullable=False, default=0)
    total_records = Column(Integer, nullable=False, default=0)
    successful_records = Column(Integer, nullable=False, default=0)
    failed_records = Column(Integer, nullable=False, default=0)
    warning_records = Column(Integer, nullable=False, default=0)
    retry_count = Column(Integer, nullable=False, default=0)

    # Baseline Expectations (recorded during validation phase)
    expected_products = Column(Integer, nullable=False, default=0)
    expected_variants = Column(Integer, nullable=False, default=0)
    expected_media_items = Column(Integer, nullable=False, default=0)
    expected_media_links = Column(Integer, nullable=False, default=0)

    # Timestamps & Errors
    started_at = Column(DateTime, nullable=True)
    completed_at = Column(DateTime, nullable=True)
    failed_at = Column(DateTime, nullable=True)
    finished_at = Column(DateTime, nullable=True)
    error_message = Column(Text, nullable=True)

    batch = relationship("MigrationBatch", back_populates="jobs")
    checkpoints = relationship("MigrationJobCheckpoint", back_populates="job", cascade="all, delete-orphan")
    media_items = relationship("MigrationMediaItem", back_populates="job", cascade="all, delete-orphan")
    errors = relationship("MigrationError", back_populates="job", cascade="all, delete-orphan")

class MigrationJobCheckpoint(Base):
    __tablename__ = "migration_job_checkpoints"

    id = Column(String(36), primary_key=True, default=generate_uuid)
    job_id = Column(String(36), ForeignKey("migration_jobs.id", ondelete="CASCADE"), nullable=False, index=True)
    phase = Column(SQLEnum(PhaseEnum), nullable=False, index=True)
    last_successful_batch = Column(Integer, nullable=False, default=0)
    total_batches = Column(Integer, nullable=False, default=0)
    processed_records = Column(Integer, nullable=False, default=0)
    failed_records = Column(Integer, nullable=False, default=0)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

    job = relationship("MigrationJob", back_populates="checkpoints")

class MigrationMediaItem(Base):
    __tablename__ = "migration_media_items"

    id = Column(String(36), primary_key=True, default=generate_uuid)
    job_id = Column(String(36), ForeignKey("migration_jobs.id", ondelete="CASCADE"), nullable=False, index=True)
    batch_number = Column(Integer, nullable=False, default=0)
    file_name = Column(String(255), nullable=False)
    archive_name = Column(String(255), nullable=True)
    zip_entry_path = Column(String(512), nullable=True)
    media_key = Column(String(255), nullable=False, index=True)
    sha256 = Column(String(64), nullable=True, index=True)  # NOT unique (allows multiple source references to map to 1 MediaAsset)
    storage_path = Column(String(512), nullable=True)
    status = Column(SQLEnum(MediaItemStatusEnum), nullable=False, default=MediaItemStatusEnum.PENDING, index=True)
    error = Column(Text, nullable=True)
    created_at = Column(DateTime, default=datetime.utcnow)

    job = relationship("MigrationJob", back_populates="media_items")

class MigrationError(Base):
    __tablename__ = "migration_errors"

    id = Column(String(36), primary_key=True, default=generate_uuid)
    job_id = Column(String(36), ForeignKey("migration_jobs.id", ondelete="CASCADE"), nullable=False, index=True)
    batch_number = Column(Integer, nullable=False, default=0)
    row_number = Column(Integer, nullable=False)
    sku = Column(String(100), nullable=True)
    product_name = Column(String(255), nullable=True)
    file_name = Column(String(255), nullable=True)
    entity_type = Column(String(50), nullable=True)
    entity_id = Column(String(36), nullable=True)
    phase = Column(String(50), nullable=False, default="VALIDATE")
    error_type = Column(String(100), nullable=False, default="DATA_ERROR")
    severity = Column(SQLEnum(ErrorSeverityEnum), nullable=False, default=ErrorSeverityEnum.ERROR)
    field_name = Column(String(100), nullable=True)
    error_message = Column(Text, nullable=False)
    suggested_fix = Column(Text, nullable=True)
    retry_status = Column(SQLEnum(RetryStatusEnum), nullable=False, default=RetryStatusEnum.UNRESOLVED)
    attempt_count = Column(Integer, nullable=False, default=1)
    raw_row_data = Column(JSON, nullable=True)
    created_at = Column(DateTime, default=datetime.utcnow)
    resolved_at = Column(DateTime, nullable=True)

    job = relationship("MigrationJob", back_populates="errors")

class MigrationSnapshot(Base):
    __tablename__ = "migration_snapshots"

    id = Column(String(36), primary_key=True, default=generate_uuid)
    batch_id = Column(String(36), ForeignKey("migration_batches.id", ondelete="CASCADE"), nullable=False)
    entity_table = Column(String(50), nullable=False)
    entity_id = Column(String(36), nullable=False)
    action_taken = Column(String(20), nullable=False)
    previous_state = Column(JSON, nullable=True)
    created_at = Column(DateTime, default=datetime.utcnow)

    batch = relationship("MigrationBatch", back_populates="snapshots")