from __future__ import annotations

from typing import Any

import django
from django.contrib.auth import get_user_model
from guardian.models import GroupObjectPermissionBase, UserObjectPermissionBase

from opencontractserver.annotations.models import Annotation
from opencontractserver.documents.models import Document
from opencontractserver.shared.defaults import jsonfield_default_value
from opencontractserver.shared.fields import NullableJSONField
from opencontractserver.shared.Models import BaseOCModel

User = get_user_model()

# Define metadata data types
METADATA_DATA_TYPES = [
    ("STRING", "String"),
    ("TEXT", "Text (Multiline)"),
    ("BOOLEAN", "Boolean"),
    ("INTEGER", "Integer"),
    ("FLOAT", "Float"),
    ("DATE", "Date"),
    ("DATETIME", "DateTime"),
    ("URL", "URL"),
    ("EMAIL", "Email"),
    ("CHOICE", "Choice (Select)"),
    ("MULTI_CHOICE", "Multiple Choice"),
    ("JSON", "JSON Object"),
]


class Fieldset(BaseOCModel):
    name = django.db.models.CharField(max_length=256, null=False, blank=False)
    description = django.db.models.TextField(null=False, blank=False)

    # NEW: Optional corpus link for metadata schemas
    corpus = django.db.models.OneToOneField(
        "corpuses.Corpus",
        null=True,
        blank=True,
        on_delete=django.db.models.CASCADE,
        related_name="metadata_schema",
        help_text="If set, this fieldset defines the metadata schema for the corpus",
    )

    class Meta:
        permissions = (
            ("permission_fieldset", "permission fieldset"),
            ("create_fieldset", "create fieldset"),
            ("read_fieldset", "read fieldset"),
            ("update_fieldset", "update fieldset"),
            ("remove_fieldset", "delete fieldset"),
            ("comment_fieldset", "comment fieldset"),
            ("publish_fieldset", "publish fieldset"),
        )


class FieldsetUserObjectPermission(UserObjectPermissionBase):
    content_object = django.db.models.ForeignKey(
        "Fieldset", on_delete=django.db.models.CASCADE
    )


class FieldsetGroupObjectPermission(GroupObjectPermissionBase):
    content_object = django.db.models.ForeignKey(
        "Fieldset", on_delete=django.db.models.CASCADE
    )


class Column(BaseOCModel):
    name = django.db.models.CharField(
        max_length=256, null=False, blank=False, default=""
    )
    fieldset = django.db.models.ForeignKey(
        "Fieldset", related_name="columns", on_delete=django.db.models.CASCADE
    )

    # NOTE(deferred): At least one of `query` or `match_text` should be non-null,
    # but enforcing at the model level is deferred because existing extract
    # pipelines may create Columns in stages. Validation lives in the mutation
    # layer instead.
    query = django.db.models.TextField(null=True, blank=True)
    match_text = django.db.models.TextField(null=True, blank=True)
    must_contain_text = django.db.models.TextField(null=True, blank=True)

    output_type = django.db.models.TextField(null=False, blank=False)
    limit_to_label = django.db.models.CharField(max_length=512, null=True, blank=True)
    instructions = django.db.models.TextField(null=True, blank=True)
    extract_is_list = django.db.models.BooleanField(default=False)
    task_name = django.db.models.CharField(
        max_length=1024,
        null=False,
        blank=False,
        default="opencontractserver.tasks.data_extract_tasks.doc_extract_query_task",
    )

    # NEW: Metadata-specific fields
    data_type = django.db.models.CharField(
        max_length=32,
        choices=METADATA_DATA_TYPES,
        null=True,
        blank=True,
        help_text="Structured data type for manual entry fields",
    )
    validation_config = NullableJSONField(
        default=jsonfield_default_value,
        null=True,
        blank=True,
        help_text="Validation rules for manual entry",
    )
    is_manual_entry = django.db.models.BooleanField(
        default=False, help_text="True for manual metadata, False for extraction"
    )
    default_value = NullableJSONField(
        default=None,
        null=True,
        blank=True,
        help_text="Default value for manual entry fields",
    )
    help_text = django.db.models.TextField(
        null=True, blank=True, help_text="Help text to display for manual entry fields"
    )
    display_order = django.db.models.IntegerField(
        default=0, help_text="Order in which to display manual entry fields"
    )

    def clean(self) -> None:
        """Validate configuration based on entry mode."""
        super().clean()

        if self.is_manual_entry:
            # Manual entry requires data_type
            if not self.data_type:
                raise django.core.exceptions.ValidationError(
                    {"data_type": "Manual entry columns require data_type"}
                )
            # Validate validation_config structure
            if self.data_type in ["CHOICE", "MULTI_CHOICE"] and self.validation_config:
                if not self.validation_config.get("choices") or not isinstance(
                    self.validation_config["choices"], list
                ):
                    raise django.core.exceptions.ValidationError(
                        {
                            "validation_config": "Choice fields require choices list in validation_config"
                        }
                    )
        else:
            # Extraction requires query or match_text
            if not (self.query or self.match_text):
                raise django.core.exceptions.ValidationError(
                    "Extraction columns require query or match_text"
                )

    class Meta:
        permissions = (
            ("permission_column", "permission column"),
            ("create_column", "create column"),
            ("read_column", "read column"),
            ("update_column", "update column"),
            ("remove_column", "delete column"),
            ("comment_column", "comment column"),
            ("publish_column", "publish column"),
        )
        indexes = [
            django.db.models.Index(fields=["fieldset", "display_order"]),
            django.db.models.Index(fields=["is_manual_entry"]),
        ]


class ColumnUserObjectPermission(UserObjectPermissionBase):
    content_object = django.db.models.ForeignKey(
        "Column", on_delete=django.db.models.CASCADE
    )


class ColumnGroupObjectPermission(GroupObjectPermissionBase):
    content_object = django.db.models.ForeignKey(
        "Column", on_delete=django.db.models.CASCADE
    )


class Extract(BaseOCModel):
    corpus = django.db.models.ForeignKey(
        "corpuses.Corpus",  # Using string reference instead of direct import
        related_name="extracts",
        on_delete=django.db.models.SET_NULL,
        null=True,
        blank=True,
    )
    documents = django.db.models.ManyToManyField(
        Document,
        related_name="extracts",
        related_query_name="extract",
        blank=True,
    )
    name = django.db.models.CharField(max_length=512, null=False, blank=False)
    fieldset = django.db.models.ForeignKey(
        "Fieldset",
        related_name="extracts",
        on_delete=django.db.models.PROTECT,
        null=False,
    )
    created = django.db.models.DateTimeField(auto_now_add=True)
    started = django.db.models.DateTimeField(null=True, blank=True)
    finished = django.db.models.DateTimeField(null=True, blank=True)
    error = django.db.models.TextField(null=True, blank=True)

    # If applicable, what CorpusAction ran?
    corpus_action = django.db.models.ForeignKey(
        "corpuses.CorpusAction",  # Using string reference instead of direct import
        related_name="extracts",
        blank=True,
        null=True,
        on_delete=django.db.models.SET_NULL,
    )

    # Iteration / lineage support. ``parent_extract`` chains an extract to the
    # iteration it was forked from so the UI can render an "Iterations" tab and
    # diff successive runs (model drift, doc-version drift, fieldset tweaks).
    # The full series is reachable by walking ``parent_extract`` upwards or
    # ``iterations`` downwards.
    parent_extract = django.db.models.ForeignKey(
        "self",
        related_name="iterations",
        on_delete=django.db.models.SET_NULL,
        null=True,
        blank=True,
        db_index=True,
        help_text=(
            "Extract this iteration was forked from. Null for the root of an "
            "iteration series."
        ),
    )
    # Run-time model configuration captured at iteration time. Forwarded as
    # ``model_override`` to ``doc_extract_query_task`` and surfaced in the UI
    # so that two iterations sharing a fieldset can be compared on model drift.
    # Schema (all keys optional): {"model": str, "temperature": float,
    # "similarity_top_k": int, "notes": str}.
    model_config = NullableJSONField(
        default=jsonfield_default_value,
        null=True,
        blank=True,
        help_text="Model/run configuration captured for this iteration.",
    )

    class Meta:
        permissions = (
            ("permission_extract", "permission extract"),
            ("create_extract", "create extract"),
            ("read_extract", "read extract"),
            ("update_extract", "update extract"),
            ("remove_extract", "delete extract"),
            ("comment_extract", "comment extract"),
            ("publish_extract", "publish extract"),
        )


class ExtractUserObjectPermission(UserObjectPermissionBase):
    content_object = django.db.models.ForeignKey(
        "Extract", on_delete=django.db.models.CASCADE
    )


class ExtractGroupObjectPermission(GroupObjectPermissionBase):
    content_object = django.db.models.ForeignKey(
        "Extract", on_delete=django.db.models.CASCADE
    )


class Datacell(BaseOCModel):
    extract = django.db.models.ForeignKey(
        "Extract",
        related_name="extracted_datacells",
        on_delete=django.db.models.CASCADE,
        null=True,  # NEW: Make nullable for manual metadata
        blank=True,
    )
    column = django.db.models.ForeignKey(
        "Column", related_name="extracted_datacells", on_delete=django.db.models.CASCADE
    )
    document = django.db.models.ForeignKey(
        Document, related_name="extracted_datacells", on_delete=django.db.models.CASCADE
    )
    sources = django.db.models.ManyToManyField(
        Annotation,
        blank=True,
        related_name="referencing_cells",
        related_query_name="referencing_cell",
    )
    data = NullableJSONField(default=jsonfield_default_value, null=True, blank=True)
    data_definition = django.db.models.TextField(null=False, blank=False)
    started = django.db.models.DateTimeField(null=True, blank=True)
    completed = django.db.models.DateTimeField(null=True, blank=True)
    failed = django.db.models.DateTimeField(null=True, blank=True)
    stacktrace = django.db.models.TextField(null=True, blank=True)

    approved_by = django.db.models.ForeignKey(
        get_user_model(),
        on_delete=django.db.models.CASCADE,
        null=True,
        blank=True,
        related_name="approved_cells",
    )
    rejected_by = django.db.models.ForeignKey(
        get_user_model(),
        on_delete=django.db.models.CASCADE,
        null=True,
        blank=True,
        related_name="rejected_cells",
    )
    corrected_data = NullableJSONField(default=None, null=True, blank=True)

    # LLM call logging for debugging/visibility
    llm_call_log = django.db.models.TextField(
        null=True,
        blank=True,
        help_text="Captured LLM message history for debugging extraction issues",
    )

    def clean(self) -> None:
        """Validate data against column configuration."""
        super().clean()

        if self.column.is_manual_entry:
            # Apply validation for manual entries based on data type and validation config
            self._validate_manual_entry()

    def _validate_manual_entry(self) -> None:
        """Validate manual entry data."""
        if not self.data:
            self.data = {}

        if "value" not in self.data:
            if self.column.validation_config.get("required"):
                raise django.core.exceptions.ValidationError(
                    f"{self.column.name} is required"
                )
            return

        value = self.data["value"]
        data_type = self.column.data_type
        config = self.column.validation_config or {}

        # Skip further validation if value is None
        if value is None:
            if config.get("required", False):
                raise django.core.exceptions.ValidationError(
                    f"{self.column.name} is required"
                )
            return

        # Type-specific validation
        if data_type == "BOOLEAN":
            if not isinstance(value, bool):
                raise django.core.exceptions.ValidationError(
                    f"{self.column.name} must be a boolean"
                )

        elif data_type == "INTEGER":
            if not isinstance(value, int) or isinstance(value, bool):
                raise django.core.exceptions.ValidationError(
                    f"{self.column.name} must be an integer"
                )
            self._validate_numeric_range(value, config, self.column.name)

        elif data_type == "FLOAT":
            if not isinstance(value, (int, float)) or isinstance(value, bool):
                raise django.core.exceptions.ValidationError(
                    f"{self.column.name} must be a number"
                )
            self._validate_numeric_range(value, config, self.column.name)

        elif data_type in ["STRING", "TEXT", "URL", "EMAIL"]:
            if not isinstance(value, str):
                raise django.core.exceptions.ValidationError(
                    f"{self.column.name} must be a string"
                )
            self._validate_string_constraints(
                value, config, data_type, self.column.name
            )

        elif data_type == "DATE":
            if not isinstance(value, str):
                raise django.core.exceptions.ValidationError(
                    f"{self.column.name} must be a date string"
                )
            try:
                from datetime import datetime

                datetime.strptime(value, "%Y-%m-%d")
            except ValueError:
                raise django.core.exceptions.ValidationError(
                    f"{self.column.name} must be in YYYY-MM-DD format"
                )

        elif data_type == "DATETIME":
            if not isinstance(value, str):
                raise django.core.exceptions.ValidationError(
                    f"{self.column.name} must be a datetime string"
                )
            try:
                from datetime import datetime

                datetime.fromisoformat(value.replace("Z", "+00:00"))
            except ValueError:
                raise django.core.exceptions.ValidationError(
                    f"{self.column.name} must be in ISO datetime format"
                )

        elif data_type == "CHOICE":
            choices = config.get("choices", [])
            if value not in choices:
                raise django.core.exceptions.ValidationError(
                    f"{self.column.name} must be one of: {', '.join(choices)}"
                )

        elif data_type == "MULTI_CHOICE":
            if not isinstance(value, list):
                raise django.core.exceptions.ValidationError(
                    f"{self.column.name} must be a list"
                )
            choices = config.get("choices", [])
            for v in value:
                if v not in choices:
                    raise django.core.exceptions.ValidationError(
                        f"{self.column.name} values must be from: {', '.join(choices)}"
                    )

        elif data_type == "JSON":
            if not isinstance(value, (dict, list)):
                raise django.core.exceptions.ValidationError(
                    f"{self.column.name} must be a JSON object or array"
                )

    def _validate_numeric_range(
        self,
        value: int | float,
        config: dict[str, Any],
        field_name: str,
    ) -> None:
        """Validate numeric constraints."""
        if "min_value" in config and value < config["min_value"]:
            raise django.core.exceptions.ValidationError(
                f"{field_name} must be at least {config['min_value']}"
            )
        if "max_value" in config and value > config["max_value"]:
            raise django.core.exceptions.ValidationError(
                f"{field_name} must be at most {config['max_value']}"
            )

    def _validate_string_constraints(
        self,
        value: str,
        config: dict[str, Any],
        data_type: str,
        field_name: str,
    ) -> None:
        """Validate string constraints."""
        if "min_length" in config and len(value) < config["min_length"]:
            raise django.core.exceptions.ValidationError(
                f"{field_name} must be at least {config['min_length']} characters"
            )
        if "max_length" in config and len(value) > config["max_length"]:
            raise django.core.exceptions.ValidationError(
                f"{field_name} must be at most {config['max_length']} characters"
            )

        if data_type == "EMAIL":
            import re

            email_pattern = r"^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$"
            if not re.match(email_pattern, value):
                raise django.core.exceptions.ValidationError(
                    f"{field_name} must be a valid email address"
                )

        elif data_type == "URL":
            import re

            url_pattern = r"^https?://[^\s/$.?#].[^\s]*$"
            if not re.match(url_pattern, value):
                raise django.core.exceptions.ValidationError(
                    f"{field_name} must be a valid URL"
                )

        if "regex_pattern" in config and config["regex_pattern"]:
            import re

            if not re.match(config["regex_pattern"], value):
                raise django.core.exceptions.ValidationError(
                    f"{field_name} format is invalid"
                )

    def save(self, *args: Any, **kwargs: Any) -> None:
        """Override save to validate manual entry data."""
        if self.column.is_manual_entry:
            self.full_clean()
        return super().save(*args, **kwargs)

    class Meta:
        permissions = (
            ("permission_datacell", "permission datacell"),
            ("create_datacell", "create datacell"),
            ("read_datacell", "read datacell"),
            ("update_datacell", "update datacell"),
            ("remove_datacell", "delete datacell"),
            ("comment_datacell", "comment datacell"),
            ("publish_datacell", "publish datacell"),
        )
        indexes = [
            # Index for batch metadata queries (filtering by document)
            django.db.models.Index(fields=["document"]),
            # Composite index for document + column lookups
            django.db.models.Index(fields=["document", "column"]),
        ]
        constraints = [
            django.db.models.UniqueConstraint(
                fields=["document", "column"],
                condition=django.db.models.Q(extract__isnull=True),
                name="unique_manual_metadata_per_doc_column",
            )
        ]


class DatacellUserObjectPermission(UserObjectPermissionBase):
    content_object = django.db.models.ForeignKey(
        "Datacell", on_delete=django.db.models.CASCADE
    )


class DatacellGroupObjectPermission(GroupObjectPermissionBase):
    content_object = django.db.models.ForeignKey(
        "Datacell", on_delete=django.db.models.CASCADE
    )
