"""
Pipeline controller - DAG-based pipeline execution.

The Pipeline class orchestrates stages in dependency order, handling
the complete render cycle from source to display.
"""

from dataclasses import dataclass, field
from typing import Any

from engine.pipeline.core import PipelineContext, Stage, StageError, StageResult
from engine.pipeline.params import PipelineParams
from engine.pipeline.registry import StageRegistry


@dataclass
class PipelineConfig:
    """Configuration for a pipeline instance."""

    source: str = "headlines"
    display: str = "terminal"
    camera: str = "vertical"
    effects: list[str] = field(default_factory=list)


class Pipeline:
    """Main pipeline orchestrator.

    Manages the execution of all stages in dependency order,
    handling initialization, processing, and cleanup.
    """

    def __init__(
        self,
        config: PipelineConfig | None = None,
        context: PipelineContext | None = None,
    ):
        self.config = config or PipelineConfig()
        self.context = context or PipelineContext()
        self._stages: dict[str, Stage] = {}
        self._execution_order: list[str] = []
        self._initialized = False

    def add_stage(self, name: str, stage: Stage) -> "Pipeline":
        """Add a stage to the pipeline."""
        self._stages[name] = stage
        return self

    def remove_stage(self, name: str) -> None:
        """Remove a stage from the pipeline."""
        if name in self._stages:
            del self._stages[name]

    def get_stage(self, name: str) -> Stage | None:
        """Get a stage by name."""
        return self._stages.get(name)

    def build(self) -> "Pipeline":
        """Build execution order based on dependencies."""
        self._execution_order = self._resolve_dependencies()
        self._initialized = True
        return self

    def _resolve_dependencies(self) -> list[str]:
        """Resolve stage execution order using topological sort."""
        ordered = []
        visited = set()
        temp_mark = set()

        def visit(name: str) -> None:
            if name in temp_mark:
                raise StageError(name, "Circular dependency detected")
            if name in visited:
                return

            temp_mark.add(name)
            stage = self._stages.get(name)
            if stage:
                for dep in stage.dependencies:
                    dep_stage = self._stages.get(dep)
                    if dep_stage:
                        visit(dep)

            temp_mark.remove(name)
            visited.add(name)
            ordered.append(name)

        for name in self._stages:
            if name not in visited:
                visit(name)

        return ordered

    def initialize(self) -> bool:
        """Initialize all stages in execution order."""
        for name in self._execution_order:
            stage = self._stages.get(name)
            if stage and not stage.init(self.context) and not stage.optional:
                return False
        return True

    def execute(self, data: Any | None = None) -> StageResult:
        """Execute the pipeline with the given input data."""
        if not self._initialized:
            self.build()

        if not self._initialized:
            return StageResult(
                success=False,
                data=None,
                error="Pipeline not initialized",
            )

        current_data = data

        for name in self._execution_order:
            stage = self._stages.get(name)
            if not stage or not stage.is_enabled():
                continue

            try:
                current_data = stage.process(current_data, self.context)
            except Exception as e:
                if not stage.optional:
                    return StageResult(
                        success=False,
                        data=current_data,
                        error=str(e),
                        stage_name=name,
                    )
                # Skip optional stage on error
                continue

        return StageResult(success=True, data=current_data)

    def cleanup(self) -> None:
        """Clean up all stages in reverse order."""
        for name in reversed(self._execution_order):
            stage = self._stages.get(name)
            if stage:
                try:
                    stage.cleanup()
                except Exception:
                    pass
        self._stages.clear()
        self._initialized = False

    @property
    def stages(self) -> dict[str, Stage]:
        """Get all stages."""
        return self._stages.copy()

    @property
    def execution_order(self) -> list[str]:
        """Get execution order."""
        return self._execution_order.copy()

    def get_stage_names(self) -> list[str]:
        """Get list of stage names."""
        return list(self._stages.keys())


class PipelineRunner:
    """High-level pipeline runner with animation support."""

    def __init__(
        self,
        pipeline: Pipeline,
        params: PipelineParams | None = None,
    ):
        self.pipeline = pipeline
        self.params = params or PipelineParams()
        self._running = False

    def start(self) -> bool:
        """Start the pipeline."""
        self._running = True
        return self.pipeline.initialize()

    def step(self, input_data: Any | None = None) -> Any:
        """Execute one pipeline step."""
        self.params.frame_number += 1
        self.context.params = self.params
        result = self.pipeline.execute(input_data)
        return result.data if result.success else None

    def stop(self) -> None:
        """Stop and clean up the pipeline."""
        self._running = False
        self.pipeline.cleanup()

    @property
    def is_running(self) -> bool:
        """Check if runner is active."""
        return self._running


def create_pipeline_from_params(params: PipelineParams) -> Pipeline:
    """Create a pipeline from PipelineParams."""
    config = PipelineConfig(
        source=params.source,
        display=params.display,
        camera=params.camera_mode,
        effects=params.effect_order,
    )
    return Pipeline(config=config)


def create_default_pipeline() -> Pipeline:
    """Create a default pipeline with all standard components."""
    pipeline = Pipeline()

    # Add source stage
    source = StageRegistry.create("source", "headlines")
    if source:
        pipeline.add_stage("source", source)

    # Add effect stages
    for effect_name in ["noise", "fade", "glitch", "firehose", "hud"]:
        effect = StageRegistry.create("effect", effect_name)
        if effect:
            pipeline.add_stage(f"effect_{effect_name}", effect)

    # Add display stage
    display = StageRegistry.create("display", "terminal")
    if display:
        pipeline.add_stage("display", display)

    return pipeline.build()