"""Validated schemas for the prompt-faithful GAP reproduction path."""

from __future__ import annotations

import re
from datetime import datetime, timezone
from typing import Any, Literal

from pydantic import BaseModel, ConfigDict, Field, model_validator


SCHEMA_VERSION = "gap-prompt-faithful-v1"


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


class CanonicalItem(StrictModel):
    item_id: str
    problem: str
    solution: str
    problem_type: Literal["proof", "calculation"] | str = "proof"
    variables: list[str] = Field(default_factory=list)
    parameters: list[str] = Field(default_factory=list)
    scientific_constants: list[str] = Field(default_factory=list)
    metadata: dict[str, Any] = Field(default_factory=dict)

    @classmethod
    def from_public_record(cls, record: dict[str, Any]) -> "CanonicalItem":
        excluded = {
            "index",
            "question",
            "solution",
            "problem_type",
            "vars",
            "params",
            "sci_consts",
            "variants",
        }
        return cls(
            item_id=str(record["index"]),
            problem=str(record["question"]),
            solution=str(record["solution"]),
            problem_type=str(record.get("problem_type", "proof")),
            variables=list(record.get("vars", [])),
            parameters=list(record.get("params", [])),
            scientific_constants=list(record.get("sci_consts", [])),
            metadata={key: value for key, value in record.items() if key not in excluded},
        )


class MutableSlot(StrictModel):
    description: str
    original: str


class KernelPlan(StrictModel):
    core_steps: list[str] = Field(min_length=1, max_length=5)
    mutable_slots: dict[str, MutableSlot]

    @model_validator(mode="after")
    def validate_content(self) -> "KernelPlan":
        if any(not step.strip() for step in self.core_steps):
            raise ValueError("core steps must be non-empty")
        if not self.mutable_slots:
            raise ValueError("at least one mutable slot is required")
        return self


class ProofPlanNode(StrictModel):
    node_id: str
    method_label: str
    dependencies: list[str] = Field(default_factory=list)

    @model_validator(mode="after")
    def validate_content(self) -> "ProofPlanNode":
        if not self.node_id.strip():
            raise ValueError("proof-plan node ID must be non-empty")
        if not self.method_label.strip():
            raise ValueError("proof-plan method label must be non-empty")
        return self


class ProofPlanDAG(StrictModel):
    """Typed path-DAG induced by Prompt-A's ordered proof-plan steps."""

    nodes: list[ProofPlanNode] = Field(min_length=1)
    terminal_node_id: str
    structure: Literal["path"] = "path"

    @classmethod
    def from_plan(cls, plan: KernelPlan) -> "ProofPlanDAG":
        nodes = [
            ProofPlanNode(
                node_id=f"n{index}",
                method_label=step,
                dependencies=[] if index == 1 else [f"n{index - 1}"],
            )
            for index, step in enumerate(plan.core_steps, start=1)
        ]
        return cls(nodes=nodes, terminal_node_id=nodes[-1].node_id)

    def method_labels_payload(self) -> list[str]:
        """Keep the judge input a sequence while making node coverage auditable."""

        return [f"{node.node_id}: {node.method_label}" for node in self.nodes]

    def validate_plan(self, plan: KernelPlan) -> "ProofPlanDAG":
        labels = [node.method_label for node in self.nodes]
        if labels != plan.core_steps:
            raise ValueError(
                "proof-plan DAG labels must equal Prompt-A core_steps in order"
            )
        return self

    @model_validator(mode="after")
    def validate_graph(self) -> "ProofPlanDAG":
        node_ids = [node.node_id for node in self.nodes]
        if len(node_ids) != len(set(node_ids)):
            raise ValueError("proof-plan DAG node IDs must be unique")

        known = set(node_ids)
        if self.terminal_node_id not in known:
            raise ValueError("proof-plan DAG terminal node is unknown")

        dependents: dict[str, list[str]] = {node_id: [] for node_id in node_ids}
        indegree = {node.node_id: len(node.dependencies) for node in self.nodes}
        for node in self.nodes:
            if len(node.dependencies) != len(set(node.dependencies)):
                raise ValueError(f"{node.node_id} has duplicate dependencies")
            for dependency in node.dependencies:
                if dependency not in known:
                    raise ValueError(
                        f"{node.node_id} depends on unknown node {dependency}"
                    )
                if dependency == node.node_id:
                    raise ValueError(f"{node.node_id} cannot depend on itself")
                dependents[dependency].append(node.node_id)

        ready = [node_id for node_id in node_ids if indegree[node_id] == 0]
        visited = 0
        while ready:
            node_id = ready.pop()
            visited += 1
            for dependent in dependents[node_id]:
                indegree[dependent] -= 1
                if indegree[dependent] == 0:
                    ready.append(dependent)
        if visited != len(node_ids):
            raise ValueError("proof-plan graph contains a cycle")

        by_id = {node.node_id: node for node in self.nodes}
        ancestors: set[str] = set()
        pending = [self.terminal_node_id]
        while pending:
            node_id = pending.pop()
            if node_id in ancestors:
                continue
            ancestors.add(node_id)
            pending.extend(by_id[node_id].dependencies)
        if ancestors != known:
            raise ValueError("every proof-plan node must lead to the terminal node")

        expected_ids = [f"n{index}" for index in range(1, len(self.nodes) + 1)]
        if node_ids != expected_ids:
            raise ValueError("path-DAG nodes must be ordered n1 through nN")
        for index, node in enumerate(self.nodes):
            expected_dependencies = [] if index == 0 else [node_ids[index - 1]]
            if node.dependencies != expected_dependencies:
                raise ValueError(
                    f"{node.node_id} must depend exactly on "
                    f"{expected_dependencies or 'no prior node'}"
                )
        if self.terminal_node_id != node_ids[-1]:
            raise ValueError("path-DAG terminal must be the final ordered node")
        return self


class KernelCandidate(StrictModel):
    question: str
    solution: str

    @model_validator(mode="after")
    def validate_content(self) -> "KernelCandidate":
        if not self.question.strip() or not self.solution.strip():
            raise ValueError("kernel question and solution must be non-empty")
        return self


class JudgeVerdict(StrictModel):
    verdict: Literal["accept", "reject"]
    step_by_step_check: str
    blocking_issues: str = ""
    patch_suggestion: str = ""

    @model_validator(mode="after")
    def validate_verdict(self) -> "JudgeVerdict":
        if self.verdict == "accept" and self.blocking_issues.strip():
            raise ValueError("accept verdict cannot contain blocking issues")
        if self.verdict == "reject" and not self.blocking_issues.strip():
            raise ValueError("reject verdict must identify a blocking issue")
        return self

    def validate_coverage(self, dag: ProofPlanDAG) -> "JudgeVerdict":
        missing = [
            node.node_id
            for node in dag.nodes
            if re.search(
                rf"(?<![A-Za-z0-9_]){re.escape(node.node_id)}(?![A-Za-z0-9_])",
                self.step_by_step_check,
            )
            is None
        ]
        if missing:
            raise ValueError(f"judge check does not cover DAG nodes: {missing}")
        return self


class IterationRecord(StrictModel):
    iteration: int
    candidate_sha256: str
    verdicts: list[JudgeVerdict]
    unanimous: bool
    pass_streak_after: int


class KernelRunResult(StrictModel):
    item_id: str
    status: Literal["accepted", "rejected"]
    plan: KernelPlan
    proof_dag: ProofPlanDAG
    accepted_candidate: KernelCandidate | None = None
    iterations: list[IterationRecord]
    rejection_reason: str = ""
    accepted_candidate_sha256: str | None = None
    schema_version: str = SCHEMA_VERSION

    @model_validator(mode="after")
    def validate_terminal_state(self) -> "KernelRunResult":
        self.proof_dag.validate_plan(self.plan)
        if self.status == "accepted" and self.accepted_candidate is None:
            raise ValueError("accepted run must include its candidate")
        if self.status == "rejected" and not self.rejection_reason:
            raise ValueError("rejected run must state a reason")
        return self


class ModelCallRecord(StrictModel):
    request_id: str
    model: str
    system_prompt: str
    user_prompt: str
    response_data: dict[str, Any]
    raw_text: str
    provider_response_id: str | None = None
    usage: dict[str, Any] = Field(default_factory=dict)
    created_at: str = Field(
        default_factory=lambda: datetime.now(timezone.utc).isoformat()
    )


class StageArtifact(StrictModel):
    item_id: str
    stage: str
    payload_sha256: str
    payload: dict[str, Any]
    request_id: str | None = None
    schema_version: str = SCHEMA_VERSION
    created_at: str = Field(
        default_factory=lambda: datetime.now(timezone.utc).isoformat()
    )