from __future__ import annotations
from typing import Dict, List, Tuple, Any, Optional
import uuid
import time
import logging
from pathlib import Path

INTERFACE_VERSION = "1.0"

logger = logging.getLogger(__name__)


def load_gx(path: str) -> Tuple[dict, List[dict], bytes]:
    """Load a .gx file and return (manifest, segments, payload).

    Thin wrapper around runtime_executor.gx_loader.load_gx().
    Reconstructs segments list from manifest['codex_lineage']['segments'].

    Args:
        path: Path to .gx file

    Returns:
        Tuple of (manifest, segments_list, payload_bytes)

    Raises:
        FileNotFoundError: If .gx file doesn't exist
        RuntimeError: If manifest is malformed
    """
    from runtime_executor.gx_loader import load_gx as loader_load_gx

    manifest, payload = loader_load_gx(path)

    # Extract segments from manifest['codex_lineage']['segments']
    codex_lineage = manifest.get("codex_lineage", {})
    segments = codex_lineage.get("segments", [])

    if not segments:
        logger.warning(f"No segments found in {path}, continuing with empty list")

    return manifest, segments, payload


def normalize_segments(
    manifest: dict,
    raw_segments: List[dict],
    payload: bytes,
) -> List[dict]:
    """Normalize raw segments into canonical Segment schema.

    Converts raw segment metadata from codex_lineage.segments into normalized form
    with required keys: id, start_line, end_line, text, symbolic_lane, semantic_role.

    Assumptions:
    - Raw segments have: id, start, end (0-based line indices)
    - Optional: lane, role metadata
    - Text extraction is stubbed (reserved for future payload analysis)

    Args:
        manifest: GX manifest dict
        raw_segments: List of raw segment dicts from codex_lineage
        payload: Compressed payload bytes (reserved for text extraction)

    Returns:
        List of normalized segment dicts conforming to Segment schema
    """
    normalized = []

    for raw_seg in raw_segments:
        seg_id = str(raw_seg.get("id", "unknown"))
        start_line = int(raw_seg.get("start", 0))
        end_line = int(raw_seg.get("end", 0))

        # Explicit lane from metadata, or infer
        explicit_lane = raw_seg.get("lane")
        if explicit_lane is not None:
            symbolic_lane = int(explicit_lane)
        else:
            symbolic_lane = _infer_lane(raw_seg)

        # Clamp to valid range [0, 7]
        symbolic_lane = max(0, min(7, symbolic_lane))

        # Semantic role: infer from segment metadata
        semantic_role = _infer_semantic_role(raw_seg)

        # Text: stub for now; in production extract from payload via byte ranges
        text = f"[segment {seg_id}: lines {start_line}–{end_line}]"

        normalized_seg = {
            "id": seg_id,
            "start_line": start_line,
            "end_line": end_line,
            "text": text,
            "symbolic_lane": symbolic_lane,
            "semantic_role": semantic_role,
            "_raw": raw_seg,  # preserve original for debugging
        }

        normalized.append(normalized_seg)

    return normalized


def _infer_lane(segment: dict) -> int:
    """Infer lane assignment from segment metadata (heuristic).

    Rules (minimum viable):
    - Structural markers → lane 0
    - Main content → lane 1 (default)
    - Comments/annotations → lane 3
    - Hints → lane 4
    - Author/meta → lane 6
    - Time/epoch → lane 7

    Args:
        segment: Raw segment dict

    Returns:
        Lane id 0–7
    """
    seg_id = str(segment.get("id", "")).lower()

    # Structural
    if any(x in seg_id for x in ["struct", "class", "def", "header", "header"]):
        return 0

    # Annotations/comments
    if any(x in seg_id for x in ["comment", "annotation", "tag"]):
        return 3

    # Hints
    if any(x in seg_id for x in ["hint", "note", "tip", "warn"]):
        return 4

    # Author/meta
    if any(x in seg_id for x in ["meta", "author", "signature"]):
        return 6

    # Time/epoch
    if any(x in seg_id for x in ["epoch", "time", "date", "version"]):
        return 7

    # Default: semantic flow
    return 1


def _infer_semantic_role(segment: dict) -> str:
    """Infer semantic role from segment metadata (heuristic).

    Args:
        segment: Raw segment dict

    Returns:
        One of: "definition", "constraint", "example", "meta", "unknown"
    """
    seg_id = str(segment.get("id", "")).lower()

    if any(x in seg_id for x in ["def", "class", "function", "declaration"]):
        return "definition"

    if any(x in seg_id for x in ["constraint", "rule", "assertion", "require"]):
        return "constraint"

    if any(x in seg_id for x in ["example", "test", "sample", "demo"]):
        return "example"

    if any(x in seg_id for x in ["meta", "note", "comment", "annotation", "tag"]):
        return "meta"

    return "unknown"


def map_lanes(segments: List[dict]) -> Dict[int, List[dict]]:
    """Map normalized segments into 0–7 lane model.

    Organizes segments by symbolic_lane into a dict where:
    - Keys: lane numbers 0–7
    - Values: lists of segments assigned to that lane

    Lane semantics (from spec):
    - 0: structural_logic
    - 1: semantic_flow
    - 2: compression_residue
    - 3: symbolic_metadata
    - 4: execution_hints
    - 5: predictive_scaffolding
    - 6: contributor_imprint
    - 7: epoch_resonance

    Args:
        segments: List of normalized segment dicts

    Returns:
        Dict[int, List[dict]] where keys are 0–7
    """
    lanes: Dict[int, List[dict]] = {i: [] for i in range(8)}

    for seg in segments:
        lane = seg.get("symbolic_lane", 1)
        # Safety clamp
        lane = max(0, min(7, lane))
        lanes[lane].append(seg)

    return lanes


def build_envelope(
    manifest: dict,
    lanes: Dict[int, List[dict]],
    payload: bytes,
    context: Optional[dict] = None,
) -> dict:
    """Build ExecutionEnvelope for LAIN from components.

    Constructs the envelope that LAIN will consume. The envelope is immutable
    from LAIN's perspective and includes all necessary context.

    Args:
        manifest: GX manifest dict
        lanes: Dict[int, List[dict]] where keys are lane ids 0–7
        payload: Compressed payload bytes
        context: Optional context overrides (runtime_flags, epoch, cognitive_mode, invocation_id)

    Returns:
        ExecutionEnvelope dict ready for LAIN.execute()
    """
    if context is None:
        context = {}

    base_context = {
        "runtime_flags": context.get("runtime_flags", {}),
        "contributor": manifest.get("contributor", "unknown"),
        "epoch": context.get("epoch"),
        "cognitive_mode": context.get("cognitive_mode", "analyze"),
        "invocation_id": context.get("invocation_id", str(uuid.uuid4())),
        "interface_version": INTERFACE_VERSION,
    }

    envelope = {
        "manifest": manifest,
        "lanes": lanes,
        "payload": payload,
        "context": base_context,
    }

    return envelope


def fuse_lanes(lane_results: Dict[int, dict]) -> dict:
    """Fuse lane results into final fused_symbol.

    Merges summaries, key_points, constraints, and open_questions
    from all lanes into a single coherent representation.

    Args:
        lane_results: Dict[lane_id, lane_result]

    Returns:
        Fused symbol dict with summary, key_points, constraints, open_questions
    """
    summaries = []
    all_key_points = []
    all_constraints = []
    all_questions = []

    for lane_id in sorted(lane_results.keys()):
        result = lane_results[lane_id]

        # Collect summaries
        if result.get("summary"):
            summaries.append(result["summary"])

        # Collect key points
        all_key_points.extend(result.get("key_points", []))

        # Collect constraints
        all_constraints.extend(result.get("constraints", []))

        # Collect open questions
        all_questions.extend(result.get("open_questions", []))

    # Merge summary
    if summaries:
        combined_summary = " | ".join(summaries)
    else:
        combined_summary = "No lanes processed"

    # Deduplicate and limit key points
    unique_key_points = list(dict.fromkeys(all_key_points))[:10]

    # Deduplicate constraints
    unique_constraints = list(dict.fromkeys(all_constraints))

    # Deduplicate questions
    unique_questions = list(dict.fromkeys(all_questions))

    return {
        "summary": combined_summary,
        "key_points": unique_key_points,
        "constraints": unique_constraints,
        "open_questions": unique_questions,
    }


def compute_resonance(lane_results: Dict[int, dict], context: Dict[str, Any]) -> dict:
    """Compute resonance metrics for lanes.

    Simple rule: resonance[lane] = 1.0 if lane produced content, else 0.0

    Args:
        lane_results: Dict[lane_id, lane_result]
        context: Execution context

    Returns:
        Dict[str, float] with resonance metrics
    """
    resonance = {}

    for lane_id in sorted(lane_results.keys()):
        result = lane_results[lane_id]

        # Lane has content if it produced a non-empty summary
        has_content = bool(result.get("summary", "").strip())
        resonance[f"lane_{lane_id}"] = 1.0 if has_content else 0.0

    return resonance


def render_output_text(fused_symbol: dict, context: Dict[str, Any]) -> str:
    """Render human-facing output text from fused_symbol.

    Format varies by cognitive_mode.

    Args:
        fused_symbol: Fused symbol dict
        context: Execution context

    Returns:
        Human-readable output string
    """
    mode = context.get("cognitive_mode", "analyze")

    mode_label = mode.upper()
    summary = fused_symbol.get("summary", "No summary")

    lines = [
        f"[{mode_label}]",
        f"{summary}",
    ]

    key_points = fused_symbol.get("key_points", [])
    if key_points:
        lines.append("")
        lines.append("Key Points:")
        for point in key_points[:5]:
            lines.append(f"  • {point}")

    constraints = fused_symbol.get("constraints", [])
    if constraints:
        lines.append("")
        lines.append("Constraints:")
        for constraint in constraints[:5]:
            lines.append(f"  • {constraint}")

    questions = fused_symbol.get("open_questions", [])
    if questions:
        lines.append("")
        lines.append("Open Questions:")
        for question in questions[:5]:
            lines.append(f"  ? {question}")

    return "\n".join(lines)


def execute_with_lain(envelope: dict) -> dict:
    """Execute ExecutionEnvelope through LAIN cognition engine.

    Real implementation: iterate through lanes, process each via lane processors,
    fuse results, and return full ExecutionResult.

    Contract:
    - Does not mutate input envelope
    - Deterministic for a given envelope
    - Errors are returned in result['diagnostics']['errors'], not raised

    Args:
        envelope: ExecutionEnvelope dict from build_envelope()

    Returns:
        ExecutionResult dict with cognition_trace, fused_symbol, output_text, diagnostics
    """
    from .lane_processors import process_lane

    start_time = time.time()

    manifest = envelope.get("manifest", {})
    lanes = envelope.get("lanes", {})
    payload = envelope.get("payload", b"")
    context = envelope.get("context", {})

    # Initialize tracking
    lane_timings: Dict[int, float] = {}
    lane_results: Dict[int, dict] = {}
    errors: List[dict] = []
    cognition_trace = []

    # Step 0: Load envelope
    cognition_trace.append({
        "step": 0,
        "lane": -1,
        "segment_id": None,
        "operation": "load_envelope",
        "input": {
            "lanes": sorted(lanes.keys()),
            "num_segments": sum(len(segs) for segs in lanes.values()),
            "manifest_version": manifest.get("version"),
        },
        "output": {},
        "note": "Loaded ExecutionEnvelope into LAIN cognition engine.",
    })

    # Process each lane
    step_num = 1
    for lane_id in sorted(lanes.keys()):
        lane_start = time.time()
        lane_segments = lanes.get(lane_id, [])

        try:
            # Call lane processor
            lane_result = process_lane(
                lane_id,
                lane_segments,
                context,
                manifest,
            )
            lane_results[lane_id] = lane_result

            # Record timing
            lane_elapsed = time.time() - lane_start
            lane_timings[lane_id] = lane_elapsed

            # Trace entry
            cognition_trace.append({
                "step": step_num,
                "lane": lane_id,
                "segment_id": None,
                "operation": f"process_lane_{lane_id}",
                "input": {"segments": len(lane_segments)},
                "output": {
                    "summary_length": len(lane_result.get("summary", "")),
                    "key_points": len(lane_result.get("key_points", [])),
                },
                "note": f"Processed lane {lane_id} with {len(lane_segments)} segments in {lane_elapsed:.4f}s.",
            })

        except Exception as e:
            lane_elapsed = time.time() - lane_start
            lane_timings[lane_id] = lane_elapsed

            err = make_error(
                "LaneProcessorError",
                f"Lane {lane_id} processing failed: {e}",
                lane=lane_id,
                recoverable=True,
            )
            errors.append(err)

            lane_results[lane_id] = {
                "summary": f"Error processing lane {lane_id}",
                "key_points": [],
                "constraints": [],
                "open_questions": [],
            }

            cognition_trace.append({
                "step": step_num,
                "lane": lane_id,
                "segment_id": None,
                "operation": f"process_lane_{lane_id}",
                "input": {"segments": len(lane_segments)},
                "output": {"error": str(e)},
                "note": f"Lane {lane_id} processing failed (recoverable).",
            })

        step_num += 1

    # Fuse lane results
    fused_symbol = fuse_lanes(lane_results)

    # Compute resonance
    resonance = compute_resonance(lane_results, context)

    # Render output text
    output_text = render_output_text(fused_symbol, context)

    elapsed = time.time() - start_time

    # Build diagnostics
    diagnostics = {
        "lane_timings": lane_timings,
        "errors": errors,
        "resonance": resonance,
        "interface_version": INTERFACE_VERSION,
        "elapsed": elapsed,
    }

    # Return ExecutionResult
    result = {
        "cognition_trace": cognition_trace,
        "fused_symbol": fused_symbol,
        "output_text": output_text,
        "diagnostics": diagnostics,
    }

    return result


def execute_gx_path(
    gx_path: str,
    context: Optional[dict] = None,
) -> dict:
    """Main entry point: load .gx file and execute through LAIN.

    Pipeline: load → normalize → map_lanes → build_envelope → execute

    Args:
        gx_path: Path to .gx file
        context: Optional context overrides

    Returns:
        ExecutionResult dict

    Raises:
        Exceptions from load_gx() if file is invalid or missing
    """
    # Load
    manifest, raw_segments, payload = load_gx(gx_path)

    # Normalize
    segments = normalize_segments(manifest, raw_segments, payload)

    # Map to lanes
    lanes = map_lanes(segments)

    # Build envelope
    envelope = build_envelope(manifest, lanes, payload, context)

    # Execute
    result = execute_with_lain(envelope)

    return result


def make_error(
    error_type: str,
    message: str,
    segment_id: Optional[str] = None,
    lane: Optional[int] = None,
    recoverable: bool = True,
) -> dict:
    """Construct a structured GXRuntimeError dict.

    Args:
        error_type: Error class (e.g. "DecodeError", "LaneError", "SegmentError")
        message: Human-readable message
        segment_id: Optional segment id if segment-specific
        lane: Optional lane id if lane-specific
        recoverable: Whether error is recoverable

    Returns:
        GXRuntimeError dict
    """
    return {
        "type": error_type,
        "message": message,
        "segment_id": segment_id,
        "lane": lane,
        "recoverable": recoverable,
    }