"""Lightweight schema helpers for micro-trend JSON validation and summarization."""

from __future__ import annotations

from typing import Any, Dict, List

REQUIRED_TOP_LEVEL_KEYS = {"meta", "global_scene", "garments", "image_level_micro_trends"}


class ValidationError(Exception):
    pass


def validate_trend_payload(payload: Any) -> Dict[str, Any]:
    """Basic structural validation to ensure expected keys/types exist."""
    if not isinstance(payload, dict):
        raise ValidationError("Payload is not a JSON object")

    missing = REQUIRED_TOP_LEVEL_KEYS - payload.keys()
    if missing:
        raise ValidationError(f"Missing top-level keys: {', '.join(sorted(missing))}")

    if not isinstance(payload.get("garments"), list):
        raise ValidationError("`garments` must be a list")

    for i, garment in enumerate(payload["garments"]):
        if not isinstance(garment, dict):
            raise ValidationError(f"garments[{i}] is not an object")
        if "category" not in garment:
            raise ValidationError(f"garments[{i}] missing `category`")
        if "print_overview" in garment and not isinstance(garment["print_overview"], dict):
            raise ValidationError(f"garments[{i}].print_overview must be an object")
        if "print_placement" in garment and not isinstance(garment["print_placement"], list):
            raise ValidationError(f"garments[{i}].print_placement must be a list")

    return payload  # type: ignore[return-value]


def _fmt_list(vals: List[str]) -> str:
    vals = [v for v in vals if v]
    if not vals:
        return ""
    if len(vals) == 1:
        return vals[0]
    return ", ".join(vals[:-1]) + f" and {vals[-1]}"


def _summarize_placement(placements: List[Dict[str, Any]]) -> str:
    if not placements:
        return "placement not specified"
    parts = []
    for p in placements[:3]:
        zone = p.get("zone") or "zone unknown"
        side = p.get("side") or "side n/a"
        coverage = p.get("coverage_percent_of_zone")
        orientation = p.get("orientation")
        note = p.get("notes")
        chunk = f"{zone} ({side}"
        if coverage is not None:
            chunk += f", ~{coverage}% coverage"
        if orientation:
            chunk += f", {orientation.lower()} orientation"
        chunk += ")"
        if note:
            chunk += f" [{note}]"
        parts.append(chunk)
    if len(placements) > 3:
        parts.append("additional placements not shown")
    return "; ".join(parts)


def _summarize_motifs(motifs: List[Dict[str, Any]]) -> str:
    if not motifs:
        return "motifs not specified"
    parts = []
    for m in motifs[:3]:
        motif = m.get("motif_type") or "motif"
        desc = m.get("motif_description")
        scale = m.get("scale")
        density = m.get("density")
        spacing = m.get("spacing_pattern")
        colors = m.get("colorways")
        chunk = motif
        if desc:
            chunk += f" ({desc})"
        details = _fmt_list([scale, density, spacing])
        if details:
            chunk += f" | {details}"
        if colors:
            chunk += f" | colors: {colors}"
        parts.append(chunk)
    if len(motifs) > 3:
        parts.append("additional motif atoms not shown")
    return "; ".join(parts)


def build_summary(payload: Dict[str, Any], max_garments: int = 3) -> List[str]:
    """Derive structured bullet points (Markdown-friendly) that narrate the JSON contents."""
    bullets: List[str] = []

    meta = payload.get("meta") or {}
    scene = payload.get("global_scene") or {}
    meta_bits = _fmt_list(
        [
            f"image quality {meta.get('image_quality')}" if meta.get("image_quality") else "",
            meta.get("image_type"),
            meta.get("view_type"),
            f"{meta.get('num_visible_garments')} garment(s)" if meta.get("num_visible_garments") is not None else "",
        ]
    )
    scene_bits = _fmt_list(
        [
            scene.get("setting"),
            "model present" if scene.get("model_present") else "",
            f"occlusions: {scene.get('occlusions_or_crops')}" if scene.get("occlusions_or_crops") else "",
        ]
    )
    bullets.append(f"**Scene:** {meta_bits or 'n/a'}; {scene_bits or 'setting n/a'}.")

    garments: List[Dict[str, Any]] = payload.get("garments", [])[:max_garments]
    for idx, g in enumerate(garments, start=1):
        cat = g.get("category") or g.get("sub_category") or "garment"
        role = g.get("role") or "primary"
        base_color = g.get("base_color_main") or "color n/a"
        secondary = _fmt_list(g.get("base_color_secondary") or [])
        fabric = g.get("base_fabric_impression")
        presence = g.get("print_presence")
        overview = g.get("print_overview") or {}
        primary_family = overview.get("primary_print_family")
        secondary_families = _fmt_list(overview.get("secondary_print_families") or [])
        style_tags = _fmt_list(overview.get("print_style_tags") or [])
        technique = overview.get("print_technique_estimate")
        placement = _summarize_placement(g.get("print_placement") or [])
        motifs = _summarize_motifs(g.get("motif_atoms") or [])
        color_story = g.get("color_story") or {}
        contrast = color_story.get("contrast_behavior")
        print_colors = _fmt_list(color_story.get("print_colors") or [])
        text_logo = g.get("text_and_logo_details") or {}
        has_text = text_logo.get("has_text_or_logo")
        text_samples = _fmt_list(text_logo.get("text_samples") or [])
        tags = g.get("micro_trend_inferences") or {}
        trend_tags = _fmt_list(
            (tags.get("print_micro_trend_tags") or [])
            + (tags.get("placement_micro_trend_tags") or [])
            + (tags.get("color_micro_trend_tags") or [])
            + (tags.get("other_detail_micro_trend_tags") or [])
        )
        confidence = g.get("confidence") or {}

        bullet = (
            f"**Garment {idx} ({role}) — {cat}:** base color {base_color}"
            f"{' with ' + secondary if secondary else ''}"
            f"{' | fabric ' + fabric if fabric else ''}"
            f"; print presence {presence or 'n/a'}"
        )
        if primary_family:
            bullet += f"; primary print family {primary_family}"
        if secondary_families:
            bullet += f"; secondary {secondary_families}"
        if style_tags:
            bullet += f"; style {style_tags}"
        if technique:
            bullet += f"; technique {technique}"
        bullet += f"; placement: {placement}"
        bullet += f"; motifs: {motifs}"
        if print_colors or contrast:
            bullet += f"; colors: ground={color_story.get('ground_color') or 'n/a'}, print={print_colors or 'n/a'}, contrast={contrast or 'n/a'}"
        if has_text:
            placements = _fmt_list(text_logo.get("placement") or [])
            style = text_logo.get("style")
            bullet += f"; text/logo present ({placements or 'placement n/a'}, style {style or 'n/a'}, samples: {text_samples or 'n/a'})"
        if trend_tags:
            bullet += f"; micro-trend tags: {trend_tags}"
        if confidence.get("overall"):
            bullet += f"; confidence overall {confidence.get('overall')}"
        bullets.append(bullet + ".")

    tags = (payload.get("image_level_micro_trends") or {}).get("deduplicated_tags") or []
    if isinstance(tags, list) and tags:
        bullets.append("**Image-level micro-trend tags:** " + ", ".join(tags) + ".")

    summary_comment = (payload.get("image_level_micro_trends") or {}).get("summary_comment")
    if isinstance(summary_comment, str) and summary_comment.strip():
        bullets.append("**Image-level summary:** " + summary_comment.strip())

    return bullets