from __future__ import annotations

import math
from datetime import datetime
from typing import Any, Literal

from pydantic import BaseModel, Field, field_validator


WorkflowDefinitionStatus = Literal["draft", "active", "archived"]
DefinitionScopeType = Literal["system", "tenant", "group", "user"]
DefinitionKind = Literal["flow", "template"]


class WorkflowPosition(BaseModel):
    x: float = 0
    y: float = 0

    @field_validator("x", "y")
    @classmethod
    def finite_coordinate(cls, value: float) -> float:
        if not math.isfinite(value):
            raise ValueError("Graph coordinates must be finite.")
        return value


class WorkflowNode(BaseModel):
    id: str = Field(min_length=1, max_length=120)
    type: str = Field(min_length=1, max_length=120)
    label: str = Field(default="", max_length=300)
    position: WorkflowPosition = Field(default_factory=WorkflowPosition)
    config: dict[str, Any] = Field(default_factory=dict)


class WorkflowEdge(BaseModel):
    id: str = Field(min_length=1, max_length=120)
    source: str = Field(min_length=1, max_length=120)
    target: str = Field(min_length=1, max_length=120)
    source_port: str = Field(default="output", min_length=1, max_length=120)
    target_port: str = Field(default="input", min_length=1, max_length=120)


class WorkflowGraph(BaseModel):
    schema_version: Literal[1] = 1
    nodes: list[WorkflowNode] = Field(default_factory=list, max_length=150)
    edges: list[WorkflowEdge] = Field(default_factory=list, max_length=300)


class WorkflowGraphValidationRequest(BaseModel):
    graph: WorkflowGraph


class WorkflowDiagnosticResponse(BaseModel):
    severity: Literal["error", "warning"]
    code: str
    message: str
    node_id: str | None = None
    field: str | None = None


class WorkflowGraphValidationResponse(BaseModel):
    valid: bool
    diagnostics: list[WorkflowDiagnosticResponse]


class WorkflowPortResponse(BaseModel):
    id: str
    label: str
    required: bool
    multiple: bool
    minimum_connections: int


class WorkflowConfigFieldResponse(BaseModel):
    id: str
    label: str
    kind: str
    required: bool
    description: str | None
    options: list[tuple[str, str]]


class WorkflowNodeTypeResponse(BaseModel):
    type: str
    category: str
    category_label: str
    label: str
    description: str
    icon: str
    input_ports: list[WorkflowPortResponse]
    output_ports: list[WorkflowPortResponse]
    config_fields: list[WorkflowConfigFieldResponse]
    default_config: dict[str, Any]


class WorkflowNodeLibraryResponse(BaseModel):
    id: str
    version: str
    allows_cycles: bool
    nodes: list[WorkflowNodeTypeResponse]


class WorkflowDefinitionRevisionResponse(BaseModel):
    id: str
    revision: int
    schema_version: int
    graph: WorkflowGraph
    content_hash: str
    library_id: str
    library_version: str
    created_by: str | None
    created_at: datetime


class WorkflowActionDecisionResponse(BaseModel):
    allowed: bool
    reason: str | None = None
    source_path: list[dict[str, Any]] = Field(default_factory=list)
    requirements: list[str] = Field(default_factory=list)
    details: dict[str, Any] = Field(default_factory=dict)


class WorkflowGovernanceResponse(BaseModel):
    scope_type: DefinitionScopeType
    scope_id: str | None
    definition_kind: DefinitionKind
    inherit_to_lower_scopes: bool
    allow_start: bool
    allow_reuse: bool
    allow_automation: bool
    derived_from_definition_id: str | None
    derived_from_revision: int | None
    derived_from_hash: str | None
    derivation_provenance: dict[str, Any] = Field(default_factory=dict)
    actions: dict[str, WorkflowActionDecisionResponse]
    automation_runtime_available: bool = False
    automation_runtime_reason: str | None = None


class WorkflowDefinitionResponse(BaseModel):
    id: str
    tenant_id: str | None
    key: str
    name: str
    description: str | None
    status: WorkflowDefinitionStatus
    current_revision: int
    active_revision: int | None
    metadata: dict[str, Any]
    created_by: str | None
    updated_by: str | None
    created_at: datetime
    updated_at: datetime
    revision: WorkflowDefinitionRevisionResponse
    governance: WorkflowGovernanceResponse


class WorkflowDefinitionListResponse(BaseModel):
    definitions: list[WorkflowDefinitionResponse]


class WorkflowDefinitionRevisionListResponse(BaseModel):
    revisions: list[WorkflowDefinitionRevisionResponse]


class WorkflowDefinitionCreateRequest(BaseModel):
    key: str | None = Field(
        default=None,
        min_length=1,
        max_length=120,
        pattern=r"^[A-Za-z0-9][A-Za-z0-9_-]*$",
    )
    name: str = Field(min_length=1, max_length=300)
    description: str | None = Field(default=None, max_length=4_000)
    graph: WorkflowGraph
    metadata: dict[str, Any] = Field(default_factory=dict)
    scope_type: DefinitionScopeType = "tenant"
    scope_id: str | None = Field(default=None, max_length=36)
    definition_kind: DefinitionKind = "flow"
    inherit_to_lower_scopes: bool = False
    allow_start: bool = True
    allow_reuse: bool = False
    allow_automation: bool = False


class WorkflowDefinitionUpdateRequest(BaseModel):
    name: str = Field(min_length=1, max_length=300)
    description: str | None = Field(default=None, max_length=4_000)
    graph: WorkflowGraph
    metadata: dict[str, Any] = Field(default_factory=dict)
    expected_revision: int = Field(ge=1)
    scope_type: DefinitionScopeType = "tenant"
    scope_id: str | None = Field(default=None, max_length=36)
    definition_kind: DefinitionKind = "flow"
    inherit_to_lower_scopes: bool = False
    allow_start: bool = True
    allow_reuse: bool = False
    allow_automation: bool = False


class WorkflowDefinitionDeriveRequest(BaseModel):
    key: str | None = Field(
        default=None,
        min_length=1,
        max_length=120,
        pattern=r"^[A-Za-z0-9][A-Za-z0-9_-]*$",
    )
    name: str = Field(min_length=1, max_length=300)
    description: str | None = Field(default=None, max_length=4_000)
    source_revision: int | None = Field(default=None, ge=1)
    metadata: dict[str, Any] = Field(default_factory=dict)
    scope_type: DefinitionScopeType = "tenant"
    scope_id: str | None = Field(default=None, max_length=36)
    definition_kind: DefinitionKind = "flow"
    inherit_to_lower_scopes: bool = False
    allow_start: bool = True
    allow_reuse: bool = False
    allow_automation: bool = False


class WorkflowDefinitionActivateRequest(BaseModel):
    revision: int | None = Field(default=None, ge=1)


class WorkflowDefinitionDeleteResponse(BaseModel):
    deleted: bool
    definition_id: str