"""Pydantic models for the resource manifest and experiment defaults.

These models are the runtime source of truth for ``configs/resources.yaml`` and
``configs/experiment.yaml``. They enforce the research invariants that
``scripts/validate_spec.py`` checks statically, so a config that loads here is
safe to use in a run. Floating revisions, MathVista in training, invented MMK12
licenses, and a malformed run matrix all fail at load time.
"""

from __future__ import annotations

import math
from pathlib import Path
from typing import Any

import yaml
from pydantic import BaseModel, ConfigDict, Field, ValidationError, model_validator

from .hashing import canonical_config_hash, is_git_revision

# Revision policy: every HF/Git resource must resolve to an exact 40-hex commit.
# ADR-0002: gold authority is a machine-checkable executor certificate; no
# per-example human edit/label/review/adjudication is permitted.
EXPECTED_MAIN_RUNS = 9
EXPECTED_RUN_COUNTS: dict[tuple[str, str], int] = {
    ("qwen35_2b", "answer_grpo"): 1,
    ("qwen35_2b", "papo_controlled"): 2,
    ("qwen35_2b", "defacto_controlled"): 2,
    ("qwen35_2b", "intervention_grpo"): 2,
    ("qwen35_2b", "evi_po"): 2,
}
# Core ingredient isolation: remove each EVI-PO auxiliary loss once. Broader
# target/PAPO/margin sweeps remain opt-in rather than an automatic GPU queue.
EXPECTED_ABLATION_RUNS = 2
EXPECTED_ABLATION_ARMS: tuple[str, ...] = (
    "evi_po_no_direction",
    "evi_po_no_evidence",
)


class ConfigError(ValueError):
    """Raised when a config file violates a research invariant."""


def _load_yaml(path: str | Path) -> dict[str, Any]:
    text = Path(path).read_text(encoding="utf-8")
    data = yaml.safe_load(text)
    if not isinstance(data, dict):
        raise ConfigError(f"{path} must contain a top-level mapping")
    return data


class ResourceModel(BaseModel):
    model_config = ConfigDict(extra="allow")

    role: str
    provider: str
    repo_id: str
    revision: str
    url: str
    license: str | None = None
    access: str = "public"
    estimated_size_bytes: int | None = None
    use: str | None = None

    @model_validator(mode="after")
    def _check_revision(self) -> ResourceModel:
        if not is_git_revision(self.revision):
            raise ConfigError(
                f"models.{self.repo_id}.revision must be a 40-hex commit, got {self.revision!r}"
            )
        return self


class ResourceDataset(BaseModel):
    model_config = ConfigDict(extra="allow")

    role: str
    provider: str
    repo_id: str
    revision: str
    url: str
    declared_license: str | None = None
    policy: str = ""
    configs: list[str] | None = None
    # Split metadata is heterogeneous across sources (flat counts for most,
    # per-config counts for MMMU), so values are left loosely typed; specific
    # guards in validate_against_resources check exact values where it matters.
    splits: dict[str, Any] | None = None
    splits_per_config: dict[str, Any] | None = None
    notes: list[str] | None = None

    @model_validator(mode="after")
    def _check_revision(self) -> ResourceDataset:
        if not is_git_revision(self.revision):
            raise ConfigError(
                f"datasets.{self.repo_id}.revision must be a 40-hex commit, got {self.revision!r}"
            )
        return self


class ResourceCheckpoint(BaseModel):
    model_config = ConfigDict(extra="allow")

    role: str
    provider: str
    repo_id: str
    revision: str
    url: str
    policy: str = ""

    @model_validator(mode="after")
    def _check_revision(self) -> ResourceCheckpoint:
        if not is_git_revision(self.revision):
            raise ConfigError(
                f"checkpoints.{self.repo_id}.revision must be a 40-hex commit, "
                f"got {self.revision!r}"
            )
        return self


class ResourceRepository(BaseModel):
    model_config = ConfigDict(extra="allow")

    url: str
    revision: str
    role: str

    @model_validator(mode="after")
    def _check_revision(self) -> ResourceRepository:
        if not is_git_revision(self.revision):
            raise ConfigError(
                f"repositories.{self.url}.revision must be a 40-hex commit, got {self.revision!r}"
            )
        return self


class ResourcesManifest(BaseModel):
    model_config = ConfigDict(extra="allow")

    manifest_version: int
    models: dict[str, ResourceModel] = Field(default_factory=dict)
    datasets: dict[str, ResourceDataset] = Field(default_factory=dict)
    checkpoints: dict[str, ResourceCheckpoint] = Field(default_factory=dict)
    repositories: dict[str, ResourceRepository] = Field(default_factory=dict)
    # C1 source-native structured worlds (PlotQA, Geometry3K) live outside the HF
    # ``datasets`` map: they are fetched from pinned GitHub revisions and feed the
    # certificate pipeline directly (docs/02 §4-6). Kept loosely typed here; the
    # adapter layer owns their detailed schema.
    structured_sources: dict[str, Any] = Field(default_factory=dict)

    def model(self, name: str) -> ResourceModel:
        if name not in self.models:
            raise ConfigError(f"unknown model resource {name!r}")
        return self.models[name]

    def dataset(self, name: str) -> ResourceDataset:
        if name not in self.datasets:
            raise ConfigError(f"unknown dataset resource {name!r}")
        return self.datasets[name]


class ExperimentRun(BaseModel):
    model_config = ConfigDict(extra="forbid")

    run_id: str
    model: str
    arm: str
    seed: int


class CommonStudent(BaseModel):
    model_config = ConfigDict(extra="allow")

    # One trainable 2B student. The v1 C1 release uses no teacher/verifier model.
    model_resource: str
    precision: str = "bf16"
    attention_implementation: str = "flash_attention_2"


class ExperimentData(BaseModel):
    model_config = ConfigDict(extra="allow")

    train_sources: dict[str, Any] = Field(default_factory=dict)
    evaluation: dict[str, Any] = Field(default_factory=dict)


class ExperimentConfig(BaseModel):
    model_config = ConfigDict(extra="allow")

    experiment_schema_version: int
    study_name: str
    reproducibility: dict[str, Any] = Field(default_factory=dict)
    labels: dict[str, Any] = Field(default_factory=dict)
    data: ExperimentData = Field(default_factory=ExperimentData)
    # Automated release/audit contract. V1 requires zero per-example model calls;
    # Terra/Luna are one-time diagnostics and never admission/gold authorities.
    automated_compilation_and_audit: dict[str, Any]
    common_student: CommonStudent
    rewards: dict[str, Any] = Field(default_factory=dict)
    main_rl_runs: list[ExperimentRun]
    # Ingredient-isolation suite (see EXPECTED_ABLATION_ARMS). Numeric knobs
    # (lambda_direction, mask_ratio, ...) live in code (rewards.ABLATION_ARM_KNOBS);
    # the manifest only pins identities.
    ablation_rl_runs: list[ExperimentRun] = Field(default_factory=list)
    sft_ablation_runs: list[dict[str, Any]] = Field(default_factory=list)

    @model_validator(mode="after")
    def _validate_run_matrix(self) -> ExperimentConfig:
        runs = self.main_rl_runs
        if len(runs) != EXPECTED_MAIN_RUNS:
            raise ConfigError(
                f"main_rl_runs must contain {EXPECTED_MAIN_RUNS} runs, found {len(runs)}"
            )
        run_ids = [run.run_id for run in runs]
        if len(run_ids) != len(set(run_ids)):
            duplicates = sorted({rid for rid in run_ids if run_ids.count(rid) > 1})
            raise ConfigError(f"duplicate run_id in main_rl_runs: {duplicates}")
        counts: dict[tuple[str, str], int] = {}
        for run in runs:
            key = (run.model, run.arm)
            counts[key] = counts.get(key, 0) + 1
        if counts != EXPECTED_RUN_COUNTS:
            raise ConfigError(f"unexpected main RL run matrix: {counts}")
        evi_po = self.rewards.get("evi_po")
        if not isinstance(evi_po, dict):
            raise ConfigError("rewards.evi_po must be an object")
        if evi_po.get("required_relationships") != ["FULL", "CONTROL", "MISSING"]:
            raise ConfigError("EVI-PO requires FULL, CONTROL, and MISSING relationships")
        if evi_po.get("optional_relationships") != ["SUBSTITUTE"]:
            raise ConfigError("EVI-PO SUBSTITUTE relationship must remain optional")
        for name in ("lambda_direction", "lambda_evidence", "margin"):
            value = evi_po.get(name)
            if (
                isinstance(value, bool)
                or not isinstance(value, int | float)
                or not math.isfinite(float(value))
                or value < 0
            ):
                raise ConfigError(f"rewards.evi_po.{name} must be non-negative")
        if evi_po.get("require_usable_response_to_image_attention") is not True:
            raise ConfigError("EVI-PO must require usable response-to-image attention")
        self._validate_ablation_matrix()
        return self

    def _validate_ablation_matrix(self) -> None:
        """Enforce the two direct EVI objective-removal runs."""
        runs = self.ablation_rl_runs
        if len(runs) != EXPECTED_ABLATION_RUNS:
            raise ConfigError(
                f"ablation_rl_runs must contain {EXPECTED_ABLATION_RUNS} runs, "
                f"found {len(runs)}"
            )
        run_ids = [run.run_id for run in runs]
        if len(run_ids) != len(set(run_ids)):
            duplicates = sorted({rid for rid in run_ids if run_ids.count(rid) > 1})
            raise ConfigError(f"duplicate run_id in ablation_rl_runs: {duplicates}")
        identities = {(run.model, run.arm, run.seed) for run in runs}
        expected = {(model, arm, seed) for arm in EXPECTED_ABLATION_ARMS
                    for model in ("qwen35_2b",) for seed in (1,)}
        if identities != expected:
            raise ConfigError(f"unexpected ablation RL run matrix: {sorted(identities)}")

    def validate_against_resources(self, resources: ResourcesManifest) -> None:
        """Enforce cross-file invariants between experiment and resources."""
        name = self.common_student.model_resource
        if name not in resources.models:
            raise ConfigError(f"common_student.model_resource references unknown model {name!r}")
        aca = self.automated_compilation_and_audit
        if aca.get("total_reasoning_vlm_calls_for_data_generation") != 0:
            raise ConfigError("v1 data generation must use exactly zero reasoning VLM calls")
        if aca.get("total_ocr_vlm_calls_for_data_generation") != 0:
            raise ConfigError("v1 data generation must use exactly zero OCR VLM calls")
        if aca.get("gold_authority") != (
            "deterministic_primary_and_reference_executor_certificates"
        ):
            raise ConfigError("v1 gold authority must be deterministic executor certificates")
        # Train sources may be HF datasets (C2) or GitHub structured worlds (C1,
        # e.g. PlotQA/Geometry3K); either is acceptable.
        for name in self.data.train_sources:
            if name not in resources.datasets and name not in resources.structured_sources:
                raise ConfigError(f"train source {name!r} is absent from resources")
        if "mathvista" in self.data.train_sources:
            raise ConfigError("MathVista must never appear in train_sources")
        for name in self.data.evaluation.get("certified_intervention", {}):
            if name not in resources.datasets and name not in resources.structured_sources:
                raise ConfigError(
                    f"certified_intervention source {name!r} is absent from resources"
                )
        for name in self.data.evaluation.get("untouched", []):
            if name not in resources.datasets:
                raise ConfigError(f"untouched source {name!r} is absent from resources.yaml")

        # Dataset-specific guards mirrored from validate_spec.py.
        mv = resources.datasets.get("mathvista")
        if mv and mv.policy != "strict_evaluation_only_training_prohibited_by_card":
            raise ConfigError("MathVista policy must remain strict evaluation-only")
        mmk = resources.datasets.get("mmk12")
        if mmk and mmk.declared_license is not None:
            raise ConfigError("MMK12 must not be assigned an invented license")
        chart = resources.datasets.get("chartqa")
        if chart:
            splits = chart.splits or {}
            if splits.get("val") != 1920 or "validation" in splits:
                raise ConfigError("ChartQA must use its actual split name 'val'")
        mmmu_pro = resources.datasets.get("mmmu_pro")
        if mmmu_pro and mmmu_pro.configs != [
            "standard (10 options)",
            "standard (4 options)",
            "vision",
        ]:
            raise ConfigError("MMMU-Pro config names must match Hugging Face metadata exactly")

    def canonical_hash(self) -> str:
        """Machine/path-independent hash of this experiment config."""
        return canonical_config_hash(self.model_dump(mode="python"))


def _format_validation_error(exc: ValidationError) -> str:
    """Render a pydantic ``ValidationError`` as a compact, human-readable string.

    Validators raise :class:`ConfigError` (a ``ValueError``), which pydantic
    wraps into a ``ValidationError``; we surface the original messages here so
    callers see the research-invariant reason rather than pydantic's envelope.
    """
    parts: list[str] = []
    for err in exc.errors():
        loc = ".".join(str(part) for part in err.get("loc", ()))
        msg = err.get("msg", "")
        if msg.startswith("Value error, "):
            msg = msg[len("Value error, ") :]
        parts.append(f"{loc}: {msg}" if loc else msg)
    return "; ".join(parts) or str(exc)


def load_resources(path: str | Path) -> ResourcesManifest:
    try:
        return ResourcesManifest.model_validate(_load_yaml(path))
    except ValidationError as exc:
        raise ConfigError(_format_validation_error(exc)) from exc


def load_experiment(path: str | Path) -> ExperimentConfig:
    try:
        return ExperimentConfig.model_validate(_load_yaml(path))
    except ValidationError as exc:
        raise ConfigError(_format_validation_error(exc)) from exc


def load_config_pair(
    resources_path: str | Path,
    experiment_path: str | Path,
) -> tuple[ResourcesManifest, ExperimentConfig]:
    """Load both configs and enforce their cross-file invariants."""
    resources = load_resources(resources_path)
    experiment = load_experiment(experiment_path)
    experiment.validate_against_resources(resources)
    return resources, experiment